Term
| Subdivisions of the Digestive System |
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Definition
Digestive Ttact (g.i)
Accessory organs |
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Term
| Digestive tract (GI tract |
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Definition
Alimentary Canal
30 foot long tube extending from mouth to anus
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine |
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Definition
| teeth, tongue, liver, gallbladder, pancreas, salivary glands |
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Term
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Definition
| Most digestive organs are in peritoneal cavity, Only duodenum, pancreas and part of the large intestine are retroperitoneal |
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Definition
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| suspends GI tract and forms serosa (visceral peritoneum) of stomach and intestines |
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Definition
forms lesser and greater omentum
lacy layer of connective tissue that contains lymph nodes, lymphatic vessels, blood vessels |
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Term
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Definition
ingestion = selective intake of food
digestion = breakdown of food into smaller molecules
absorption = uptake of nutrients into blood or lymph
defacation = elimination of undigested material |
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Definition
motility = muscular contractions that break up food, mix it with enzymes & move it along
secretion = digestive enzymes & hormones
membrane transport = absorption of nutrients |
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Definition
physical breakdown of food into smaller particles
cutting & grinding of teeth
churning action of stomach & intestines |
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Term
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Definition
hydrolysis reactions
enzymes from saliva, stomach, pancreas & intestines break macromolecules into their monomers polysaccharides into monosaccharides proteins into amino acids fats into glycerol and fatty acids nucleic acids into nucleotides |
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Term
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Definition
| Anterior opening of mouth |
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Term
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Definition
| Posterior opening to throat |
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Term
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Definition
keep food between teeth for chewing
essential for speech & suckling in infants |
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Definition
| is sensitive, muscular manipulator of food |
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Definition
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Term
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Definition
| secrete saliva, tonsils in root |
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Definition
| allows breathing and chewing at the same time |
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Term
| Periodontal ligament (tooth structure) |
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Definition
is modified periosteum
anchors into bone |
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Definition
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Term
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Definition
| is noncellular secretion formed during development |
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Term
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Definition
leads into pulp cavity
nerves and blood vessels |
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Term
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Definition
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Term
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Definition
Ingestion
Taste
Mastication - chewing
breaks food into smaller pieces to be swallowed
mixes more easily with digestive enzymes
Begins chemical digestion of startch
deglutition - swallowing
Speech
Respiration |
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Term
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Definition
| Total of 1 to 1.5 Lof saliva per day |
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Term
| Hypotonic solutions of 99.5% water and solutes: |
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Definition
amylase = begins starch digestion Lingual
lipase = digests fat after reaches the stomach must be activated by HCl in stomach
Mucus = aids swallowing by lubricating & binding food
lysozyme = enzyme that kills bacteria
IgA = antibodies to inhibit bacterial growth electrolytes = Na+, K+, Cl-, phosphate & bicarbonate |
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Definition
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Term
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Definition
Moistens Mouth Partially digests starch -
salivary amylase Inhibits bacterial growth Dissolves molecules to stimulate taste buds Moistens food
Aids swallowing by binding food together into bolus |
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Term
| Intrinsic Salivary Glands |
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Definition
Indefinite number dispersed throughout oral tissue
Buccal - cheeks
Labial - lips
Lingual - tongue
Secrete continuously at a constant rate
Contains lysozyme & lingual lipase |
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Term
| 3 pairs extrinsic glands connected to oral cavity by ducts (salivilary glands) |
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Definition
parotid, submandibuluar and sublingual mucous glands
secrete mucous serous glands secrete amylase & electrolytes |
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Term
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Definition
throat - skeletal muscle
Longitudinal and circular
Superior, middle & inferior constrictors
Force food downward while swallowing
Inferior constrictor remains constricted when food is NOT being swallowed
Excludes air from the esophagus |
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Term
| Tissue Layers of the GI Tract |
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Definition
mucosa
epithelium
lamina propria - loose connective tissue muscularis mucosae - thin layer of smooth muscle
submucosa
muscularis externa
inner circular layer
outer longitudinal layer
adventitia or Serosa
areolar tissue or mesothelium |
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Term
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Definition
Dorsal to trachea
Straight muscular tube 25-30 cm long skeletal muscle in upper part & smooth in bottom
Extends from pharynx to cardiac stomach
Passes through esophageal hiatus in the diaphragm
Opening in the diaphragm
Lower esophageal sphincter closes orifice to reflux
Enters stomach at the cardiac oriface |
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Term
| Swallowing or Deglutition |
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Definition
Series of muscular contractions coordinated by swallowing center in medulla & pons
Buccal phase tongue collects food & pushes it back into oropharynx
Pharyngeal-esophageal phase |
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Term
| Pharyngeal-esophageal phase |
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Definition
| soft palate rises & blocks nasopharynx infrahyoid muscles lift larynx & epiglottis is folded back pharyngeal constrictors push bolus down esophagus liquids reach stomach in 2 seconds food bolus may take 8 seconds |
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Term
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Definition
Muscular sac in upper left abdominal cavity Below the diaphragm
J - shaped organ with lesser & greater curvatures Rugae - wrinkles 50 ml when empty 1 to 1.5 Lafter a typical meal Maximum of 4 L When extremely full, the stomach will extend into the pelvis |
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Term
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Definition
| mechanically breaks up food particles liquifies the food resulting soupy mixture is called chyme Begins chemical digestion of protein & fat Stomach does not absorb any significant amount of nutrients does absorb aspirin & some lipid-soluble drugs All blood drained from stomach is filtered through the liver before returning to heart |
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Term
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Definition
cardiac region - just inside cardiac orifice
fundus - domed portion superior to esophageal opening
body - main portion of organ also called the gastric region
pyloric region - narrow inferior end
- antrum – funnel
- pyloric canal – terminates at pyloris
pylorus is opening to duodenum thick ring of smooth muscle forms a pyloric sphincter |
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Term
| Cells of the Gastric Glands |
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Definition
mucous cells – produce mucus
regenerative cells - divide rapidly to produce new cells that migrate upwards towards surface parietal cells - secrete HCl acid & intrinsic factor chief cells- secrete rennin & lipase in infancy secrete pepsinogen throughout life Enteroendocrine (G) cells- secrete hormones & paracrine messengers |
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Term
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Definition
2 to 3 L of gastric juice per day
Mostly H2O, HCl & pepsin |
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Term
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Definition
Stomach acid with pH as low as 0.8
Activates enzymes - pepsin & lingual lipase
Breaks up connective tissues & plant cell walls
Liquifies food to form chyme
Converts iron to usable forms
ingested ferric ions (Fe+3) to ferrous ions (Fe+2) that can be absorbed & utilized for hemoglobin synthesis
destroys ingested bacteria & pathogens |
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Term
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Definition
3 ml of chyme enters the duodenum of the small intestine at one time
Typical meal is emptied from stomach in 4 hours
A liquid meal is emptied much sooner
A meal high in fat leaves the stomach in ~6 hours |
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Term
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Definition
Induced by
excessive stretching of stomach
psychological stimuli
chemical irritants (bacterial toxins) |
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Term
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Definition
in medulla causes lower esophageal sphincter to relax as diaphragm & abdominal muscles contract
contents forced up the esophagus
may even expel contents of small intestine |
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Term
| Protection of the Stomach |
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Definition
Mucous coat – alkaline
Epithelial cell replacement
Cells live just 3 to 6 days
tight junctions
Prevent gastric juices from seeping between epithelial cells |
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Term
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Definition
HCl and pepsin erode stomach wall
Can occur in duodenum and esophagus as well
Sometimes caused by - smoking, aspirin
Treatment – reduce acidity
Now know that many ulcers are caused by bacteria |
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Term
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Definition
Acid-resistant bacterium that invades the mucosa
Treatment: antibiotics |
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Term
| Regulation of Gastric Function (Phase 1) |
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Definition
cephalic phase
Stomach is being controlled by the brain
Sight, smell taste or thought of food
Hypothalamus sends signal to medulla
Medulla signals vagus nerves
Vagus nerves stimulates enteric nervous system of the stomach
enteric nerves stimulate gastric secretions prior to swallowing |
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Term
| Regulation of Gastric Function (Phase 1) |
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Definition
cephalic phase
Stomach is being controlled by the brain
Sight, smell taste or thought of food
Hypothalamus sends signal to medulla
Medulla signals vagus nerves
Vagus nerves stimulates enteric nervous system of the stomach
enteric nerves stimulate gastric secretions prior to swallowing |
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Term
| Regulation of Gastric Function (Phase 2) |
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Definition
Gastric phase
stomach controls itself
stretches as food arrives
activated by presence of food or semidigested protein
secretion stimulated by acetylcholine, histamine & gastrin |
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Term
| Regulation of Gastric Function (Phase 3) |
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Definition
intestinal phase
duodenum regulates gastric activity through hormones & nervous reflexes
gastric activity increases if duodenum is stretched or amino acids in chyme cause gastrin release |
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Term
| Enterogastric reflex (stage 3) |
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Definition
| duodenum inhibits stomach |
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Term
Chyme stimulates duodenal cells to release
(phase 3) |
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Definition
Secretin
Cholecystokinin (CCK)
gastric inhibitory peptide
all 3 suppress gastric secretion & motility |
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Term
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Definition
3 lb. organ located inferior to the diaphragm
4 lobes - right, left, quadrate, caudate
falciform ligament separates left and right
round ligament is remnant of umbilical vein
gallbladder adheres to ventral surface between right and quadrate lobes |
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Term
| Microscopic Anatomy of Liver |
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Definition
Tiny cylinders called hepatic lobules (2mm by 1mm)
Central vein surrounded by sheets of hepatocyte cells separated by sinusoids lined with fenestrated epithelium
Blood filtered by hepatocytes on way to central vein
nutrients, toxins, bile pigments, drugs, bacteria & debris filtered |
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Term
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Definition
bile secreted into bile canaliculi
Bile ductules
right & left hepatic ducts join outside the liver
form common hepatic duct
joins cystic duct from gallbladder
forms common bile duct
joins pancreatic duct
forms hepatopancreatic ampulla
empties into duodenum at major duodenal papilla
hepatopancreatic sphincter - regulates release of bile & pancreatic juice |
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Term
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Definition
Synthesized from cholesterol
Most reabsorbed in the small intestine & recycled
Some modified in the large intestine
Become promoters of colon cancer
Less fat in the diet = less bile release |
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Term
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Definition
High fat and low fiber content
Associated with colon cancer
High incidence: US, Germany, Austria, Sweden
Countries with low fat and high fiber diets have less incidence of colon cancer
Studies show that Asian men in US eating high fat/low fiber diet have colon cancer incidence comparable to Caucasian men
Fiber binds bile acids!
Less fat absorbed
Bile acids in large intestine are unavailable for modification
Low colon cancer rate in Finland despite a high fat diet
Finish eat lots of brown bread |
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Term
| Gall Stones (biliary calculi) |
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Definition
Composed of cholesterol, calcium carbonate, bilirubin
Up to 1 cm in diameter
Cause great pain
Block bile flow
jaundice
poor fat digestion
Impaired fat-soluble vitamin absorption (ie Vitamin E)
Treatments
Surgical removal, stone-dissolving drugs, lithotripsy
Stent – tube in bile duct that increases diameter thus allowing small stones to pass |
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Term
| Hormonal Control of Secretion |
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Definition
cholecystokinin - released from duodenum in response to arrival of acid and fat causes contraction of gallbladder secretion of pancreatic enzymes relaxes hepatopancreatic sphincter
secretin - released from duodenum in response to acidic chyme stimulates all ducts to secrete sodium bicarbonate
gastrin – secreted from stomach & duodenum weakly stimulates gallbladder contraction & pancreatic enzyme secretion |
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Term
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Definition
Most chemical digestion and nutrient absorption
6-7 m long in cadaver
2 m long in live person due to muscle tone
Highly folded
Villi & microvilli increase surface area |
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Term
| Gross Anatomy of Small Intestine |
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Definition
duodenum
jejunum is next 8 ft. (in upper abdomen) absorption of nutrients
ileum is last 12 ft. (in lower abdomen) ends at ileocecal junction with large intestine |
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Term
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Definition
curves around head of pancreas
retroperitoneal along with pancreas (~10 in.)
receives stomach contents, pancreatic juice & bile
neutralizes stomach acids
emulsifies fats
inactivates pepsin by pH increase
pancreatic enzymes present |
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Term
| Large Surface Area of Small Intestine |
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Definition
Circular folds - in mucosa and submucosa chyme flows in spiral path causing more contact slows chyme for maximum digestion and absorption
villi - blood vessels & lymphatics (lacteal) nutrient absorption
microvilli - 1 micron tall brush border on cells brush border enzymes for final stages of digestion |
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Term
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Definition
Pores opening between villi lead to intestinal crypts
- absorptive cells, goblet cells & at base, rapidly dividing cells life span of 3-6 days as migrate up to surface & get sloughed off & digested paneth cells with unknown function
Brunner’s glands in submucosa secrete bicarbonate mucus
Peyer patches are populations of lymphocytes to fight pathogens Secrete 1-2L of intestinal juice/day water & mucus, pH 7.4-7.8 |
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Term
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Definition
Mixes chyme with intestinal juice, bile & pancreatic juice
Churns chyme to increase contact with mucosa for absorption & digestion
Moves residue towards large intestine segmentation random ringlike constrictions mix & churn contents 12 times per minute in duodenum
Peristaltic waves begin in duodenum but each one moves further down suppressed by refilling of stomach
Food in stomach causes gastroileal reflex relaxing of valve & filling of cecum |
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Term
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Definition
Gradual movement of contents towards the colon
Migrating motor complex controls waves of contraction
second wave begins distal to where first wave began |
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Term
| Carbohydrate Digestion in Small Intestine |
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Definition
act upon oligosaccharides
Maltose
Sucrose
Lactose
Fructose
lactose indigestible after age 4 in most humans
due to a lack of lactose |
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Term
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Definition
Sodium-glucose transport proteins (SGLT) in membrane help absorb glucose and galactose
Fructose absorbed by facilitated diffusion then converted to glucose inside the cell |
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Term
| Protein Digestion and Absorption |
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Definition
Pepsin has optimal pH of 1.5 to 3.5
inactivated when passes into duodenum and mixes with alkaline pancreatic juice ________
Pancreatic enzymes take over protein digestion
hydrolyze polypeptides into shorter oligopeptides
Brush border enzymes finish task, producing amino acids that are absorbed into intestinal epithelial cells
amino acid cotransporters move into epithelial cells
facilitated diffusion moves amino acids out into blood stream
Infants absorb proteins by pinocytosis (maternal IgA enters blood) |
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Term
| Nucleic Acids, Vitamins, and Minerals |
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Definition
Nucleases hydrolyze DNA & RNA to nucleotides
brush border enzymes split them into phosphate ions, ribose or deoxyribose sugar & nitrogenous bases
Vitamins are absorbed unchanged A, D, E & K with other lipids B complex & C by simple diffusion B12 if bound to intrinsic factor
Minerals are absorbed all along small intestine Na+ cotransported with sugars & amino acids Cl- exchanged for bicarbonate reversing stomach Iron & calcium absorbed as needed |
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Term
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Definition
Digestive tract receives about 9 L of water/day
Water is absorbed by osmosis following the absorption of salts & organic nutrients
Diarrhea occurs when too little water is absorbed feces pass through too quickly if irritated feces contains high concentrations of a solute (lactose) |
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Term
| Gross Anatomy of Large Intestine |
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Definition
5 feet long and 2.5 inches in diameter in cadaver
Called “large” because of diameter, not length
Haustra (pleural)/ Haustrum (singular)
pouches due to strips of longitudinal muscle
Begins as cecum & appendix
Ascending, transverse and descending colon
sigmoid colon leading down into pelvis
rectum – 3 folds/valves
allow retention of feces while passing gas
Anal canal(3 cm) Anus (opening) |
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Term
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Definition
Cecum – large pouch located inferior to iliocecal junction
Appendix – located at the lower end of the cecum
rich in lymphocytes to collect pathogens
may become infected |
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Term
| Bacterial Flora & Intestinal Gas |
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Definition
Bacterial flora populate large intestine
diet dictates what type of bacteria thrive
ferment cellulose & other undigested carbohydrates synthesize vitamins B and K humans don’t get enough from diet alone!
Flatus/Flatulence (gas)- average person produces 500 mL per day most is swallowed air can contain methane, hydrogen sulfide, indole & skatole that produce the odor |
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Term
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Definition
Transit time is 12 to 24 hours reabsorbs water and electrolytes
Feces consist of water & solids bacteria, mucus, undigested fiber, fat & sloughed epithelial cells
Haustral contractions occur every 30 minutes distension of a haustrum stimulates it to contract
triggered by gastrocolic and duodenocolic reflexes filling of the stomach & duodenum stimulates motility moves residue for several centimeters with each contraction |
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Term
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Definition
Anal canal is 3 cm total length
Anal columns are longitudinal ridges separated by mucus secreting anal sinuses |
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Term
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Definition
Stretching of the rectum stimulates defecation
intrinsic defecation reflex via the myenteric plexus
causes muscularis to contract & internal sphincter to relax
relatively weak contractions
defecation occurs only if external anal sphincter is voluntarily relaxed
parasympathetic defecation reflex involves spinal cord
stretching of rectum sends sensory signals to spinal cord
splanchnic nerves return signals intensifying peristalsis
Abdominal contractions increase abdominal pressure as levator ani lifts anal canal upwards
feces will fall away |
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Term
| Neural Control of Defecation |
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Definition
1. Filling of the rectum
2. Reflex contraction of rectum & relaxation of internal anal sphincter
3. Voluntary relaxation of external sphincter |
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Term
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Definition
3rd leading cause of cancer deaths in US
Always begins as a benign polyp
1st colonoscopy recommended at 50 years of age
earlier if there is a family history
Some are genetically predisposed to certain types of colon cancer
Majority of cases are caused by environmental factors |
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Term
| Female Reproductive System |
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Definition
•Produce and deliver gametes
•Provide nutrition and space for fetal development
•Give birth
•Nourish infant |
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Term
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Definition
•Primary sex organ
•Ovaries produce
–Eggs (ova) – 2 million!
–female hormones
•Almond-shaped organ
•3 cm by 1.5 cm by 1 cm
•Each egg develops in its own fluid-filled folliclethat changes as the egg matures
•Ovum is released by ovulation
–bursting of the follicle
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Term
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Definition
•Ligaments
–attached to uterus by ovarian ligament
–attached to pelvic wall by suspensory ligament
•contains ovarian artery, vein and nerves
–anchored to broad ligament by mesovarium |
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Term
| Secondary Sex Organs (Genitalia) |
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Definition
•Internal genitalia
–duct system consisting of
•uterine tubes
•Uterus
•Vagina
•External genitalia
–clitoris, labia minora, and labia majora
–occupy the perineum
–accessory glands beneath the skin provide lubrication |
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Term
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Definition
•10 cm long, muscular tube from ovary to uterus
•Major portions of tube
–near uterus forms a narrow isthmus
–middle portion is the body (ampulla)
–flared distally into infundibulum
with fimbriae (feathery end)
•cilia beat toward uterus
•Smooth muscle contractions toward uterus |
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Term
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Definition
•Thick-walled, pear-shaped muscular chamber
•3 areas: fundus, body, cervix |
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Term
| Layers of the Uterine Wall |
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Definition
•perimetrium is external serosa layer
•myometrium is middle muscular layer
–1 cm thick in nonpregnant uterus
–smooth muscle running in all directions
•produces labor contractions to expel fetus during delivery
•endometrium is simple columnar epithelium with thick layer compound tubular glands
•stratum functionalis is superficial 1/2 shed with each period
•stratum basalis is deeper layer that regenerates a new stratum functionalis with each menstrual cycle
•embryo attachment
•rich in white blood cells (WBCs) |
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Term
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Definition
•Scrape cervix and look at cells under microscope
•Class I – no abnormalities
•Class II – inflammation, infection, irritability
•Class III – dysplasia à abnormal cell growth
•Class IV – localized malignancy
•Class V – invasive malignancy |
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Term
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Definition
•8-10 cm long, distensible muscular tube
–allows for discharge of menstrual fluid, receipt of semen and birth of baby
•hymen – mucosal membrane that is broken at first intercourse or before
•Vaginal rugae – wrinkles in muscular wall
•Acidic pH (3.5-4) – bacteria ferment glycogen to lactic acid à prevents growth of pathogenic organisms
•Acidic pH is neutralized by the alkaline pH of semen, so that sperm are not killed
•Balance between bacteria and yeast residing in vagina
–when bacteria are killed, a yeast infection can develop
•Tilted posteriorly between rectum & urethra |
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Term
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Definition
• labia majora
–thick folds of skin with pubic hair
• labia minora
–inner, thin, hairless folds
–form vestibule containing urethral & vaginal openings
–form hoodlike prepuce over clitoris
•Clitoris
–erotic, sensory organ
–homologous to male penis |
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Term
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Definition
•Vestibular bulbs
–erectile tissue that fills with blood during arousal
–tightens around penis
•Paraurethral and greater vestibular glands
–open into vestibule for lubrication |
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Term
| Seconday Sex Characteristics |
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Definition
•Breasts
•Distribution of body fat
•Flair of pelvis
•Fine body hair
•High voice |
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Term
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Definition
•Mound of tissue overlying the pectoralis major
–conical body of breast has nipple at its apex
–Axillary tail in armpit contains many lymphatic vessels
•Nipple is surrounded by areola (colored zone)
–dermal blood vessels are closer to surface
–melanocytes darken during pregnancy for infant recognition
–rich in nerves
–smooth muscle contracts wrinkling the skin & erecting the nipple in response to cold, touch & arousal
–sparse hairs
–Areolar glands – visible bumps that secrete an oily substance
•Protect against chapping during nursing
•If nonlactating, contains little glandular tissue just a system of branching ducts and fat tissue |
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Term
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Definition
•1 out of every 8 American women
•Tumors begin with cells from mammary ducts
–may metastasize by way of lymphatics
•Symptoms include
–palpable lump
– skin puckering
–changes in skin texture
–drainage from the nipple
•Most breast cancer is nonhereditary
–some stimulated by estrogen
•Risk factors include aging, ionizing radiation, carcinogenic chemicals, alcohol, smoking & fat intake
–70% lack risk factors
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Term
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Definition
•Begins at age 9 or 10 for most girls in the U.S.
•Triggered by rising levels of GnRH which stimulate anterior pituitary to produce FSH & LH
–FSH stimulates follicles to secrete estrogen & progesterone
•secondary sex organs maturation, in height & width of pelvis
•prepares uterus for pregnancy
•thelarche = development of breasts
•pubarche = growth of pubic & axillary hair
–apocrine & sebaceous gland secretion
•menarche = first menstrual period (age 12)
–requires at least 17% body fat in teenager, 22% in adult, in order to sustain pregnancy and lactation
–in 1860 avg. age was 16.5 (difference due mainly to nutrition) |
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Term
| Climacteric and Menopause |
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Definition
•Midlife change in hormone secretion accompanied by menopause (cessation of menstruation)
–Occurs at 45-55 years; average age of 52
•Age related depletion of follicles (>1000) means less ovarian secretion of estrogen & progesterone
–Atrophy of uterus, vagina & breasts
–skin becomes thinner, bone mass declines, cholesterol levels rise and risks of cardiovascular disease increase
–Hot flashes (sudden dilation of cutaneous arteries) due to hormone fluctuations; occur several times a day
•HRT = low dose estrogen & progesterone therapy |
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Term
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Definition
•Averages 28 days but ranges from 20 to 45
•Hormone cycle produces hierarchy of control
–hypothalamus® pituitary ® ovaries ® uterus
•follicular phase (2 weeks)
–menstruation occurs during first 3 to 5 days
–uterus replaces lost endometrium & follicles grow
•Postovulatory or luteal phase (2 weeks)
–Corpus luteum stimulates endometrial thickening
–endometrium lost again if pregnancy does not occur |
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Term
| Ovarian Cycle - Follicular Phase |
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Definition
•From beginning of menstruation(1) to ovulation(14)
–most variable part of cycle
•Contains menstrual and preovulatory phases |
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Term
| Ovarian Cycle - Menstrual Phase |
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Definition
•During discharge of menstrual fluid (days 1-5)
•The primary oocytes that began developing on day 25 of previous cycle have been transformed into secondary follicles by day 5 |
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Term
| Ovarian Cycle - Preovulatory Phase |
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Definition
•From days 6 to 14, one follicle has advanced to the graafian stage & protrudes from surface of ovary
•Egg stopped at meiosis II metaphase II stage |
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Term
| Ovarian Cycle - Ovulation |
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Definition
•High estrogen levels cause anterior pituitary to secrete LH
– increased blood flow causes follicle to swell rapidly
–collagenase weakens ovarian wall
–fluid oozes out with oocyte |
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Term
| Ovarian Cycle - Postovulatory Phase |
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Definition
•LH directs empty follicle in ovary to form corpus luteum
–secretes androgens that are converted to progesterone
–progesterone stimulates changes in the uterine lining
– if pregnancy occurs, corpus luteum acts on uterus for ~? months
–no pregnancy à corpus luteum atrophies & loss of progesterone brings on |
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Term
| Menstrual Cycle -Proliferative Phase |
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Definition
•Time of rebuilding of endometrial tissue lost at last menstruation -- mitosis occurs in stratum basalis
•Result of estrogen from developing follicles
•Reaches 2-3 mm in thickness |
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Term
| Menstrual Cycle - Secretory Phase |
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Definition
•Further thickening of endometrium due to secretion & fluid accumulation -- not mitosis
•Due to progesterone stimulation of glands
•Reaches 5-6 mm in thickness |
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Term
| Menstrual Cycle-Premenstrual Phase |
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Definition
•Progesterone level falls due to atrophy of corpus luteum
•Spiral arteries constrict causing endometrial ischemia
•Pools of blood accumulate in stratum functionalis |
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Term
| Menstrual Cycle - Menstrual Phase |
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Definition
•Blood, serous fluid and endometrial tissue are discharged
•Average woman loses 40 mL of blood & 35 mL of serous fluid --- contains fibrinolysin so it does not clot |
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Term
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Definition
•Excitement and Plateau
–vasocongestion –myotonia –hyperemia -
–serous fluid (vaginal transudate) seeps into vagina
–lower 1/3 of vagina constricts
•narrowing forms orgasmic platform
–uterus stands erect
•Orgasm
–1-2 seconds of “paralysis” just prior to orgasm
–3-5 strong contractions
–cervix plunges into the vagina
–Uterus exhibits peristalsis
–Tachycardia
–Hyperventilation
–Flush on chest, neck & face
•Resolution
–Cardiovascular and respiratory responses return to normal
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Term
|
Definition
•Behavorial methods
•Barrier or spermacidal methods
•Hormonal methods
•Surgical sterilization
•Prevention of implantation |
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Term
|
Definition
•Cutting and tying or clamping the genital ducts
•Blocks passage of sperm/eggs
•Reversal is expensive and often unsuccessful
•vasectomy - males
–Sever ductus (Vas) deferens
–Small incision in scrotum
•Tubal ligation – females
–Sever uterine tubes
–Can be done laproscopically
•Small incisions with a laproscope inserted for viewing |
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Term
| Prevention of Implantation |
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Definition
•Intrauterine Device (IUD)
–Inserted through the cervix
–Embedded into the uterine wall
–Prevents implantation of a developing zygote
•Emergency Contraceptive Pills (ECPs)
–“morning after” pill
–Most states require a prescription
–High doses of female hormones
–Taken within 72 hours following intercourse
–Induces menstruation in 2 weeks
–Can work via
•inhibiting ovulation
•inhibiting sperm or egg transport
•prevent implantation |
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Term
| Reproductive System Overview |
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Definition
•Primary sex organs
–organs that produce the gametes -
•Secondary sex organs - essential for reproduction
–male – testes, penis
•Storage, survival and transportation of sperm
–female – uterine tubes, uterus, vagina
•receive the sperm, zygote development & nourishment of the developing fetus
•Secondary sex characteristics
–features that develop at puberty to attract a mate
•pubic, axillary & facial hair, scent glands, body morphology and low-pitched voice in males |
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Term
| Role of the Sex Chromosomes |
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Definition
•Our cells contain 23 pairs of chromosomes
–22 pairs of autosomes
–1 pair of sex chromosomes (XY males: XX females)
•males produce 50% Y carrying sperm and 50% X carrying
•all eggs carry the X sex chromosome
•Sex of the child is
determined by the type
of sperm that fertilizes
the mother’s egg |
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Term
| Hormones and Sex Differentiation |
|
Definition
•Gonads begin to develop at 6 weeks as gonadal ridges
•2 sets of ducts exist at that time
–Mesonephric ducts develop into reproductive system in males (paramesonephric ducts degenerate)
–paramesonephric ducts develop into reproductive tract in females (mesonephric ducts degenerate)
•SRY gene (sex-determining region of Y gene)
–in males, codes for a protein that causes testis to secrete testosterone and mullerian-inhibiting factor
•these hormones bind to receptors on target cells and determine which ducts degenerate, thus determining development of genitalia
•Female development due to absence of male hormones & not presence of estrogen (at levels due to pregnancy) |
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Term
| Androgen-Insensitivity Syndrome (AIS) |
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Definition
•XY embryo
•Produces testosterone
•Target cells are missing the receptors
•Testosterone cannot bind to target cells
•External female genitalia develops
•At puberty, breasts & other feminine secondary sex characteristic develop
•Detected in puberty due to lack of menstruation
•No ovaries,uterus or vagina, but testes in abdomen
•High risk for testicular cancer if testes are not removed |
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Term
| Development of External Genitalia |
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Definition
•All 8 week old fetuses have same 3 structures
–by end of week 9, begin to show sexual differentiation
–distinctly male or female by end of week 12 |
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Term
|
Definition
•Begin development near the kidney
–gubernaculum (cordlike structure containing muscle) extends from the gonad to the abdominopelvic floor
–it shortens and guides the testes to the scrotum
–create inguinal canal, pass through abdominal wall
•Descent begins in weeks 6-10 & is finished by 28
•Location outside the pelvic cavity is essential for low temperatures needed for sperm production
•cryporchidism – 1 or both testes don’t descend prior to birth
–Occurs in 3% of males
–May descend on their own within first year of life
–Treat with hormone therapy or surgery |
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Term
|
Definition
•2 oval organs, 4 cm long & 2.5 cm in diameter
•Covered anteriorly (tunica vaginalis) that descended into the scrotum with the testes
•Tunica albuginea = white fibrous capsule
–septa divide the organ into compartments containing seminiferous tubules where sperm are produced
•each tubule is lined with a thick germinal epithelium composed of germ cells in the process of becoming sperm
–sustentacular cells promote sperm cell development
•blood-testis barrier is formed by tight junctions between sustentacular cells -- separating sperm from immune system
–interstitial cells between tubules - testosterone |
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Term
| Testis and Associated Structures |
|
Definition
•Low BP of testicular artery results in poor O2 supply
–sperm develop very large mitochondria helping them survive the hypoxic environment of the female reproductive tract |
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Term
|
Definition
•Pendulous pouch holding the testes
–divided into 2 compartments by median septum
–left testicle is lower
•Skin contains sebaceous glands, nerves and hair
•Testicular thermoregulation is necessary since sperm are not produced at core body temp (2C cooler)
–cremaster muscle and dartos muscle = contract or relax to move testes
•Cold – muscles contract to bring testes closer to body
–pampiniform plexus = veins ascend near testicular artery
•countercurrent heat exchange - cools arterial blood entering testis |
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Term
|
Definition
•Efferent ductules
•epididymis
•Ductus (vas) deferens
•ejaculatory duct |
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Term
|
Definition
Efferent ductules
Epididymis
Vas deferens
Ampulla
Duct of seminal vesicle
Ejaculatory duct
urethra |
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Term
|
Definition
•Regions of male urethra: prostatic, membranous and penile
–totals ~20 cm long |
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Term
|
Definition
•Seminal vesicles
–posterior to bladder
–empties into ampulla
•prostate gland
–below bladder
–Surrounds urethra & ejaculatory duct
•bulbourethral (Cowper) glands
–near bulb of penis
–empty into penile urethra
–lubricating fluid
–neutralizes acidity of urine |
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Term
|
Definition
•½ Internal root and ½ visible shaft and glans
–external portion is ~ 4 in. long when flaccid
–skin over shaft is loosely attached allowing expansion
•extends over glans as prepuce or foreskin
–glans – sebaceous glands à smegma
•Mycobacterium smegmatis |
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Term
|
Definition
•Reproductive system remains dormant for many years after birth
–surge of pituitary gonadotropins begins development
•10-12 in most boys; 8-10 in most girls
•puberty = period from onset of gonadotropin secretion until the ability to reproduce sexually is attained
–Females - first menstrual period
–Males - first ejaculation of viable sperm |
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Term
|
Definition
•Mature hypothalamus produces GnRH
•Stimulation of gonadotrope cells in anterior pituitary causes secretion of FSH and LH
–LH stimulates interstitial cells to produce testosterone
–FSH stimulates sustentacular cells to secrete androgen-binding protein
•interacts with testosterone to stimulate spermatogensis
•Effects of testosterone
–stimulates spermatogenesis & enlargement 2nd sexual organs
•penis, testes, scrotum, ducts, glands and muscle mass enlarge
•hair, scent and sebaceous glands develop
•stimulates erythropoiesis and libido
•During adulthood, testosterone sustains libido, spermatogenesis and reproductive tract |
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Term
| Aging and Sexual Function |
|
Definition
•Decline in testosterone secretion
–peak secretion at 7 mg/day at age 20
–declines to 1/5 of that by age 80
•Rise in FSH and LH secretion after age 50 produces male climacteric (menopause)
–mood changes, hot flashes & “illusions of suffocation”
•Impotence (erectile dysfunction)
–20% of those in 60s and 50% of those in 80s
–0ver 90% of impotent men remain able to ejaculate |
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Term
|
Definition
•head is pear-shaped front end
–4 to 5 microns long structure containing the nucleus, acrosome and basal body of the tail flagella
•nucleus contains haploid set of chromosomes
•acrosome contains enzymes that penetrate the egg
•tail is divided into 3 regions
–midpiece contains mitochondria around axoneme of the flagella (produce ATP for flagellar movement)
–principal piece is __________ surrounded by fibers
–endpiece is very narrow tip of flagella |
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Term
|
Definition
•2-5 mL of fluid expelled during orgasm
–60% seminal vesicle fluid
–30% prostate gland fluid
– 10% sperm
•normal sperm count is 50 – 120 million mL
•< 25 million/mL is associated with infertility
•Other components of semen
–fructose provide energy for sperm motility
–prostaglandins stimulate female peristaltic contractions
–seminogelin – sticky fibrin-like protein
–serine protease - liquefies semen 20-30 min after ejaculation
–spermine is a base stabilizing sperm pH at 7.2 to 7.6 |
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Term
| Male Sexual Response - Anatomy |
|
Definition
•Arteries of penis
– dorsal and deep
•branches of internal pudendal artery
–deep artery supplies corpora cavernosa
•dilation causes an erection
–normal penile blood supply comes from dorsal artery
•Nerves of penis
–abundance of tactile, pressure and temperature receptors
–Dorsal nerve of penis and internal pudendal nerves lead to integrating center in sacral spinal cord
–both autonomic and somatic motor fibers carry impulses from integrating center to penis |
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Term
|
Definition
•Excitement is characterized by
–vasocongestion (blood engorgement) of genitals
–myotonia
–increases in heart rate, BP, and pulmonary ventilation
•Initiated by many different erotic stimuli
–sights, sounds, aromas, touch, thoughts
•Erection of penis is due to parasympathetic triggering of nitric oxide (NO) secretion
–dilation of deep arteries and filling of erectile bodies with blood
•Erection is maintained during plateau phase
–heart rate, BP, and pulmonary ventilation are maintained |
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Term
|
Definition
•Climax (orgasm) is 15 second reaction that includes the discharge of semen (ejaculation)
•Ejaculation
–emission = sympathetic nervous system propels sperm through ducts as glandular secretions are added
–expulsion = semen in urethra activates muscular contractions that lead to expulsion
•Ejaculation and orgasm are not the same
–can occur separately |
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Term
|
Definition
•Sympathetic signals constrict internal pudendal artery and reduce blood flow to penis
–penis becomes soft and flaccid (detumescence)
•Cardiovascular and respiratory responses return to normal
•Refractory period (10 minutes to few hours) |
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Term
| Bacterial Sexually Transmitted Diseases |
|
Definition
•Bacteria are a common cause of STDs
•Bacteria causing STDs survive poorly on inanimate objects and are thus transmitted via sexual intercourse
•Examples of bacterial STDs
– gonorrhea
– syphilis
– chlamydia |
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Term
|
Definition
•Neisseria gonorrhoeae
•Painful urination and pus-filled discharge
•20% of women are asymptomatic
•Can scar uterine tubes
– infertility
•Incubation period
–2 to 5 days |
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Term
|
Definition
•Treponema pallidum
•Can be passed sexually and through saliva
•incubation stage – organism multiplies
•Primary stage – chancre formation
–hard, painless nondischarging lesion
•Primary latent stage – no signs
•Secondary stage – rashes & skin eruptions
–on and off for ~ 5 years – highly contagious
•Secondary latent stage – no signs
–may even test negative
•Tertiary stage – permanent damage
–often to cardiovascular & nervous systems |
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Term
|
Definition
•Chlamydia trachomatis
•One of the most prevalent diseases in US
–contracted by 3 to 5 million Americans/year
•Signs and Symptoms
–Females-most are asymptomatic
–Males-painful urination, pus discharge from the penis
•Chlamydial infection in adolescence is associated with increased risk of cervical cancer]
•Lymphogranuloma
venereum
–severe form of disease
–characterized by a transient genital lesion and a bubo in the groin
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Term
|
Definition
•Herpes simplex virus type 2 (genital) – main cause
•Herpes simplex virus type 1 (oral)
•Virus can become latent in nerve cells
•Signs and Symptoms
–Small blisters on or around the genitals or rectum
•labia, vagina, cervix of women
•penis, foreskin of males
•prostate and seminal vesicles can be affected
•Treatment requires administration of acyclovir or other antiviral agents to lessen symptoms
– no cure!
•One out of five adolescents and adults, have had genital HSV infection |
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Term
|
Definition
• human papillomavirus (HPV)
•At least 50% of sexually active men and women acquire genital HPV infection at some point in their lives
•Direct contact with infected individuals or fomites
•Growths ranging from soft, small bumps to very large sites on the genitals
–external genitalia - penis, vulva, scrotum, perineum, and perianal skin
–uterine cervix, vagina, urethra, anus, and mouth
–intra-anal warts are observed predominantly in patients who have had receptive anal intercourse
•Incubation period - 3 to 4 months
•Treatment: Removal of warts
•vaccine - protects females from the four types of HPV that cause most cervical cancers and genital warts |
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Term
|
Definition
•protozoan STD
•Trichomonas vaginalis
•Signs and Symptoms
–Females-foul-smelling, yellow-green vaginal discharge and vaginal irritation
–Males-typically asymptomatic
•Transmission primarily via sexual intercourse
•Most common curable STD in women |
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Term
|
Definition
–12 tiny ciliated ducts collecting & transporting sperm to epididymis |
|
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Term
|
Definition
–18 ft long coiled duct adhering to the posterior of testis
–site of sperm maturation & storage
–Reabsorbs fluid and dead sperm
–Stored sperm are viable for 40-60 days |
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Term
|
Definition
peristalsis during orgasm
–muscular tube 45 cm long passing up from scrotum through inguinal canal to posterior surface of bladder |
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Term
|
Definition
| 2 cm duct passing through prostate gland to empty into urethra |
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