Term
| why do essential physiological processes of life require energy and raw materials? |
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Definition
for homeostasis, movement, growth, repair, reproduction, electrochemical activity, etc
Autotrophs can live on inorganic nutrients alone whereas heterotrophs require complex organic compounds from other organisms in their diet. |
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Term
carbohydrates provide 17kj/g of energy.
how much do proteins and lipids provide? |
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Definition
lipids 22kj/g for membranes, energy storage, heat insulation
proteins 39kj/g for structural components, enzymes |
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Term
| whta do vitamins mainly needed for? |
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Definition
they are mainly co-factors for enzymes
inorganic salts are required for bones, respiratory pigments etc
water is required to act as a solvent, a transport medium and lubricant etc |
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Term
| list some fucntions of water (5) |
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Definition
solvent
transportation
hydrostatic support (eg eyeball)
evaporative cooling
cleaning agent (eg for eyes) |
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Term
out of the 20 amino acids, 8 are essential amino acids. this means they must be obtained from food in a pre fabricated form. name these 8 essential amino acids
neumonic Tymothy Took Mega PILL Viagra |
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Definition
Trytophan
Methionine
Valine
Threonine
Phenylalanine
Leucine
Isoleucine
Lysine |
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Term
| how many calories is 1 joule? |
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Definition
0.239 calories
woman who does light work requires 8.8 x 106 J/day
man light work = 10.5
man moderate work = 14.3
man heavy work = 18.9
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Term
the average water intake is 2500mls
how is this intake accounted for (3) |
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Definition
Drinks 1,400ml
Food 800ml
cellular respiration 300ml
a little water is produced as a by product of cellular respiration |
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Term
| the average total water loss is also 2,500 ml. how is this accounted for? (3) |
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Definition
Urine 1500ml
faeces 350 ml
Sweat 550ml |
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Term
| name the 4 basic digestive processes |
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Definition
- Digestion
- Absorbtion
- Motility
- Secretion
Digestion, absorbtion and motility done by GI Tract
Secretion done by Accessory glands |
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Term
what am i? i am a tube essentially 4.5 metres in length and my job invoves the physical and chemical breakdown of food.
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Definition
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Term
| the accessory glands secrete digestive fluids into the GI Tact. what makes up the accessory glands? |
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Definition
salivary glands
pancreas
liver
gall bladder |
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Term
| between the pharynx and the esophagus which sphincter would you find? |
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Definition
| the upper esophageal sphincter |
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Term
| which sphincter would you find between the esophagus and the stomach? |
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Definition
| the lower esophageal sphuncter |
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Term
| which sphincter would you find between the small intestine and the colon? |
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Definition
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Term
match the function with the organ:
im involved in mechanical breakdown of food with saliva, initiation of chemical digestion of carbs by salivary amylase |
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Definition
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Term
| which part of the body is involved in conduction of food to the esophagus? |
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Definition
the pharynx
the esophagus is involved in food conduction to the stomach |
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Term
| the stomach is involved in mechanical breakdown of food, secretion of acid, pepsinogen and intrinsic factor. What does intrinsic factor do? |
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Definition
Intrinsic factor helps with the absorbtion of Vitamin B12 across the wall of the stomach
the stomach initiates the chemical digestion of proteins by pepsin, secretion of gastrin into bloodstream and the transformation of food into chyme. |
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Term
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Definition
gastrin is a peptide hormone that stimulates secretion of HCL (gastric acid) by the parietal cells of the stomach. it aids in gastric motility
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Term
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Definition
| Chyme is the semifluid mass of partly digested food expelled by the stomach into the duodenum |
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Term
| where does absorbtion of digestion end-products, water, ions and vitamins occur? |
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Definition
the small intestine
also the secretion of enterogastrones into blood stream and secretion of bicarbonate rich fluid. |
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Term
| what are enterogastrones - give some examples of enterogastrones |
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Definition
an enterogastrone is any hormone secreted by the mucosa of the duodenum in the lower GI tract in response to dietary lipids that inhibits the forward motion of contents of chyme.
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Term
| where does absorption of ions and water, transformation of chyme into poop and storage of poop occur? |
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Definition
in the colon.
the poop is stored in the rectum prior to elimination
the anus controld defacation
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Term
| what does saliva contain? (4) |
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Definition
amylase
lysozyme
mucus
bicarbonate |
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Term
| which nervous system helps regulate perostalsis in the GI tract? |
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Definition
| Nervus plexus - enteric nervous sytem |
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Term
name the 4 layers of the GI tract starting from the middle outwards
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Definition
1. Mucosa - made from 3 layers of epithelium
2. Submucosa - made from connective tissue, blood and lymphatic vessels. This part has a very rich blood supply
3. Muscalaris is made from a circular and a longitudinal layer
4. Serosa - outermost layer made from connective tissue that supports the intestines |
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Term
| Name the 3 layers of the mucosa? |
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Definition
Mucous membrane
lamina propria
muscalaris mucosae
the lamina propria is made from connective tissue, capillaries, nerves and lymphoid tissue
the mucous membrane is composed of epithelial cells known as enterocytes which include absorptive cells, exocrine cells, goblet cells & endocrine cells |
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Term
| which layer of the mucosa is made from epithelial enterocytes including absorptive, exocrine, goblet and endocrine cells? |
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Definition
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Term
| name the 3 main mouth and salivary glands? |
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Definition
Sublingual gland
Submandibular gland
Parotid gland |
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Term
saliva is secreted at 0.5ml/min. it contains salivary amylase that digests glycogen and start and lingual lipase
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Definition
Lubrication (mucus)
Buffering and diluting noxiou substances
Antibiotic action through lysozyme & lactoferrin
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Term
| which muuscular tube ~25cm long connect the pharynx to the stomach? |
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Definition
the esophagus
its upper and lower esophageal sphincters are usually closed but backflow can occur leading to heartburn |
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Term
| which type of muscle would you find in the upper 1/3 of the esophagus? |
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Definition
in the upper 1/3 you would find skeletal muscle
in the lower 2/3 you would find smooth muscle |
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Term
| which organ can expand from 50ml to 1-2 litres? |
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Definition
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Term
| where are parietal cells contained? what do they secrete? |
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Definition
they are contained in the mucosa of the gastric glands.
upto 2 litres of HCL can be secreted per day!
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Term
| which cells secrete pepsinogen? |
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Definition
cheif cells
pepsinogen is the inactive zymogen to pepsin
pepsinogen is activated when it encounters the acidic environment of the stomach |
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Term
true or false?
mucus (neck cells), gastric lipases, intrinsic factor and rennin are also secreted into the stomach? |
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Definition
this is true
Intrinsic factor is required for the absorbtion of vitamin B12
and rennin coagulates milk. |
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Term
| describe the mechanism of gastric acid secretion |
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Definition
H+ ions made from CO2 and H20 by carbonic anhydrase (CA) are actively transported into the lumen in exchange for K+
Bicarbonate ions are exchanged for chloride ions, which diffuse into the lumen.
The nett result is accumulation of HCL in the lumen |
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Term
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Definition
it is an inactive enzyme precursor
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Term
| name the zymogen synthesised in the stomach which gives rise to pepsin |
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Definition
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Term
| what is the zymogen to the active enzyme Chymotrypsin produced in the pancreas? |
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Definition
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Term
name the zymogens for Trypsin, Carboxypeptidase and Elastase, all of which are synthesised in the pancreas
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Definition
Trypsinogen - Trypsin
Procarboxypeptidase - Carboxypeptidase
Proelastase - Elastase |
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Term
| in the first stage of the activation of Chymotrypsinogen, Trypsin cuts between which amino acid numbers? |
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Definition
between 15 and 16
the final Chymotrypsin has 3 subunits: A, B and C linked by interchain disulphide bonds |
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Term
| pepsinogen is not activated until it encounters what? |
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Definition
HCL in the stomach.
Once activated, it becomes pepsin. Pepsin can activate more pepsinogen.
Pepsin then starts to degrade proteins into smaller polypeptides |
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