Term
| What are the 7 functions of the respiratory system? |
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Definition
1. Provides oxygen
2. Eliminates carbon dioxide
3. Regulates blood pH
4. Forms speech sounds
5. Defends against microbes
6. Modifies chemical messengers
7. Traps and dissolves clots |
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Term
| What are the 3 conducting zones of respiratory system and what constitutes each one? (8) |
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Definition
Upper Conducting Zone
Nasal Cavity (also important for sense of smell)
Pharynx
Larynx (also allows speech and helps to protect airway when swallowing
--
Lower Conducting zone: area from the trachea to the bronchioles that forms a branching network of tubes leading into the respiratory zone
As the tubes become smaller, the amount of cartilage decreases, the epithelium flattens (pseudostratified to simple columnar to simple cuboidal) and the amount of smooth muscle increases.
Trachea: flexible tube with C-rings of cartilage
Bronchi: Primary bronchi are similar to trachea, but secondary and tertiary bronchi have incomplete plates of cartilage. Epithelium is ciliated and there are lots of mucus secreting cells
Bronchioles: tubes that lack cartilage and contain smooth muscle that is regulated by the autonomic nervous system to change the radius of the bronchioles and the resistance to airflow. Cilia and mucus secreting cells are fewer compared with the bronchi and disappear entirely in the smaller bronchioles.
--
Respiratory zone: includes respiratory bronchioles alveolar ducts and alveoli
Alveoli are air sacs with simple squamous epithelium and a thin layer of connective tissue that fuses with the connective tissue of tightly associated pulmonary capillaries to form the respiratory membrane. Some of the epithelia lining the alveoli are surfactant secreting (type II) cells, and alveolar macrophages are also present. |
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Term
| What are the 5 stages of respiration? |
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Definition
1. Ventilation (by bulk flow that results from a pressure gradient)
2. Exchange of oxygen and carbon dioxide between lung and blood (by diffusion)
3. Transport of gases to tissues via blood (by bulk flow that results from a pressure gradient but is also dependent on the gas content of blood))
4. Exchange of oxygen and carbon dioxide between blood and tissues (by diffusion)
5. Cellular utilization of oxygen and production of carbon dioxide |
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Term
| What is the formula for airflow? |
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Definition
| Airflow = (alveolar pressure –atmospheric pressure) /airway resistance |
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Term
| What are the three pulmonary pressures? |
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Definition
Alveolar (intrapulmonary) pressure
Intrapleural pressure: pressure in the intrapleural fluid surrounding the lungs
(normally ~-4mmhg compared with atmospheric between breaths)
Transpulmonary pressure: pressure difference between alveoli and pleural fluid. |
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Term
| Define inspiration and expiration |
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Definition
Inspiration: an active process that increases thoracic cavity volume and decreases the intra-alveolar pressure below atmospheric pressure
Expiration: process that decreases thoracic cavity volume and increases the intra-alveolar pressure above atmospheric pressure |
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Term
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Definition
| The lung contains connective tissues with a large number of elastic fibers. The presence of these fibers explains the tendency of the lung to passively recoil to a smaller volume when it is inflated. These elastic fibers increase the work required to expand the lungs during inspiration but aid in expiration |
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Term
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Definition
| a complex disease characterized, in part, by a loss of elastic tissue in the lungs such that expiration becomes difficult due to a loss of elastic recoil. |
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Term
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Definition
compliance describes the ease with which the tissues of the lung expand with muscle effort ( compliance is inversely related to elasticity).
Compliance = change in volume/change in (Palv- Pip) Decreased compliance increases the muscle effort required during inspiration
Lung compliance is reduced by fibrosis of the lung in response to chronic inhalation of particulate matter |
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Term
| What are the two normal determinants of lung compliance? |
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Definition
Stretchability of lung tissues (inversely related to amount of elastic tissue)
Surface tension of fluid lining alveoli (decreased by surfactant) |
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Term
| What two functions does surfactant serve, and what cells secrete it? |
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Definition
Lowers alveolar surface tension of the alveoli and maintains normal lung compliance
Contains phospholipids bound to protein that decreases hydrogen bonding between water molecules
Secreted by type II epithelia cells in alveoli |
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Term
| Define Respiratory Distress Syndrome |
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Definition
| a disease in newborns due to a deficiency in surfactant |
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Term
| What are the three determinants of airflow resistance? |
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Definition
Viscosity of air
Length of airway
Radius of airway (most important!) Resistance is proportional to 1/(radius)4 |
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Term
|
Definition
measurement of the volumes of air moved into and out of the lungs
Use: assessment of the changes in ventilation with disease |
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Term
| Dr. Golden's definition of vital capacity |
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Definition
| maximum volume of air that can be expired after a maximal inspiration |
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Term
| Minute Ventilation (total ventilation/pulmonary ventilation) |
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Definition
Air moved into the lungs per minute
= tidal volume x respiratory rate |
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Term
|
Definition
volume of air unavailable for gas exchange
= anatomic dead space + alveolar dead space
air in conducting zone + air in nonfunctional alveoli
(generally estimated to be approximately 150 mls) |
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Term
|
Definition
| the airways of the mouth, nose, pharynx, larynx, trachea, bronchi, and bronchioles |
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Term
| Alveolar Ventilation Rate Formula |
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Definition
| = (tidal volume – dead space) x respiratory rate |
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Term
| Three determinants of alveolar gas exchange |
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Definition
Alveolar ventilation determines the concentration of a gas in the lung
Blood perfusion of lungs: brings blood from tissues to the respiratory membrane
Diffusion between lungs and blood: depends on the concentration gradient between the alveoli and the blood and the resistance of the respiratory membrane. The resistance is normally very small due to the thinness of the respiratory membrane and the presence of a large surface area for exchange. |
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Term
| Atmospheric Pressure Formula (4) |
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Definition
| H2O vapor pressure + PO2 + PC02 + PN2 |
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Term
| What is the vapor pressure of water at body temperature? (37*C) |
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Definition
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Term
| What are the 4 factors that affect the alveolar concentration/partial pressures of O2 and CO2? |
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Definition
Atmospheric pressure: partial pressure changes in proportion to atmospheric pressure. For example the partial pressure of oxygen decreases as atmospheric pressure decreases with altitude.
Gas content of air: For example the partial pressure of oxygen in the alveoli can be increased by increasing the fraction of oxygen in air.
Alveolar ventilation: increasing alveolar ventilation increases the alveolar partial pressure of O2 and decreases the alveolar partial pressure of CO2
Rate of cellular O2 consumption/ CO2 production affects the alveolar partial pressure of these gases by changing the O2 and CO2 in venous blood and the gradient for diffusion from the alveoli into the blood |
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Term
| What percentage of O2 is dissolved in blood plasma and what percentage is attached to hemoglobin? |
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Definition
O2 Dissolved in plasma: 1.5%
Bound to hemoglobin: 98.5% |
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Term
Deoxyhemoglobin
vs
Oxyhemoglobin |
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Definition
| Deoxyhemoglobin + 4 O2 = Oxyhemoglobin |
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Term
| ~ Hemoglobin Dissociation Curve (figure 22.20) |
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Definition
| as the partial pressure of oxygen in blood plasma increases, the amount of O2 bound to HB increases, but the relationship is not linear (see the Hb saturation curve) |
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Term
| What are the three factors that affect the O2 affinity of Hgb? |
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Definition
PCO2: as carbon dioxide binds to amino acids in Hgb, the affinity of Hgb for O2 decreases
[H+]: as H+ binds to amino acids in Hgb, the affinity of Hgb for O2 decreases
Temperature: as temperature increases the affinity of Hgb for O2 decreases |
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Term
| In what percentages of what forms is CO2 found in the blood as? |
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Definition
Dissolved CO2 in plasma: 7%
Bound to hgb: 15-25%
As bicarbonate ion (HCO-3): ~70% |
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Term
| Three control factors for ventilation |
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Definition
1. Arterial PCO2
2. Arterial [H+]
3. Arterial PO2 (much less important!) |
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Term
| 2 Sensors that help to regulate breathing |
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Definition
1. Chemosensitive areas in the brain (respond to CO2 and H+)
2. Chemoreceptors in the aorta and carotid arteries (respond primarily to CO2 , H+ and O2)
* note that 02 is much less important as a regulator of breathing than CO2 and H+ |
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Term
| What are the three components to the integrating center from respiration? |
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Definition
I. Respiratory center in medulla: primary integrating center for control of respiration.
II. Regulatory centers in the pons (communicates with medulla for fine tuning of ventilation).
III. Conscious control of ventilation is possible via descending pathways to the medulla and pons |
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Term
| What are the two kinds of mechanical digestion that occur? |
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Definition
Chewing breaks food into smaller pieces
Contraction of smooth muscle functions to mix, break into smaller pieces, and propel |
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Term
| Describe chemical digestion (4) |
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Definition
Breakdown of Polymers to Monomers by Hydrolysis
Secretions necessary for chemical digestion (Enzymes; bile, HCl; HCO3-)
Absorption into Blood/Lymph
Elimination of Wastes |
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Term
| What are the 5 components of the alimentary canal? |
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Definition
Mouth
Esophagus
Stomach
Small Intestine
Large Intestine |
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Term
| What are the 4 accessory organs to digestion? |
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Definition
Salivary Glands
Pancreas
Gall Bladder
Liver |
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Term
| What are the two major components of the digestive system? |
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Definition
Alimentary Canal
Accessory Organs |
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Term
| What are the three roles of intestinal mucosa? |
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Definition
| Protection Absorption and Secretion |
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Term
| Describe the 4 layers of the alimentary canal and the features of each (15) |
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Definition
Mucosa (Protection Absorption and Secretion).
Inner Layer: Epithelium, Lamina Propria, Muscularis Mucosa.
Submucosa: Contains Blood Vessels And Nerves, Glands And Lymphatic Tissue
Muscular Layer (muscularis externa):
Circular Fibers (Change Tube Radius)
Longitudinal Layers (Shorten Tube)
Serous Layer:
Visceral Peritoneum (Protective) |
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Term
| What type of epithelium would you expect to find in the mucosa of the esophagus and small intestine? |
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Definition
Esophagus – stratified squamous
Small intestine – simple columnar |
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Term
| Why is smooth muscle better for GI function? |
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Definition
| Smooth Muscle can contract even when stretched excessively due to organization and longer myosin filaments and irregular overlapping arrangement of the actin and myosin; Functions as a Single Unit Sheet of Muscle |
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Term
| Four general aspects of smooth muscle sheets |
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Definition
Smooth Muscle Cells are linked by gap junctions
Cells are activated by pacemaker cells that control the rate of contraction and stimulate contraction automatically
Contractions are graded
Hormonal, local, and neural signals affect the force of contractions |
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Term
| What are the sensors integrating centers, and effectors of the GI process? (6) |
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Definition
Sensors monitor conditions inside the lumen of the digestive tract:
Chemoreceptors (activated by chemicals)
Mechanoreceptors (activated by stretch)
Integrating Centers are most often also found within the digestive tract; although the brain also has integrating function
Effectors include smooth muscle or glands that are part of the digestive tract or accessory organs |
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Term
| What are the three neural controls of the GI process? |
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Definition
Enteric Nervous System (most important).
Parasympathetic (Generally Excitatory).
Sympathetic (Generally Inhibitory but less important) |
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Term
| Describe hormonal control of the GI process (3) |
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Definition
Hormones are released into the blood in response to mechanical and chemical stimuli from within the lumen of the GI tract.
The hormones may act to stimulate or inhibit activity within a compartment or between different compartments (e.g. stomach vs. small intestines)
Paracrine Agents: signals released locally (e.g. histamine) |
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Term
| Distinguish between the cephalic, gastric and intestinal phases with respect to regulation of digestion. (6) |
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Definition
All, overlap
Cephalic Phase : (Initiated By CNS). Priming phase. Sensors are complex, do not sense things in GI tract, such as being hungry, stimulating digestivie tract: growling of stomach. Smelling food and becoming hungry, or chewing gum and becoming hungry.
Gastric Phase: (Initiated By Presence Of Food In Stomach). Stimulated by chemoreceptors, and mechanoreceptors.
Intestinal Phase : (Initiated By Presence Of Food In Intestine).
Motility is decreased during the intestinal phase by neural and hormonal (e.g. Secretin and CCK) reflexes in response to activation of stretch and chemoreceptors in the small intestine
Parasympathetic Stimulation promotes some release of acid by parietal cells during the cephalic phase and local enteric stimulation in response to stomach stretching during the gastric phase |
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Term
| What are the 4 functions of the mouth? |
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Definition
| Ingestion, Mastication, Lubrication, Spreads saliva throughout food |
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Term
| What are the 4 functions of saliva |
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Definition
| Moistens Food, Amylase Begins Digestion of Starch; HCO3- Regulates pH, Antimicrobial |
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Term
| What are the three salivary glands? |
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Definition
| Parotid, submandibular and sublingual |
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Term
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Definition
| A complex reflex stimulated by sensors in the oropharynx. The integrating center is in the medulla and effectors include muscles in the pharynx and esophagus. |
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Term
| What are the 4 regions of the stomach? |
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Definition
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Term
| Functions of the stomach (5) |
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Definition
Mechanical Digestion (churning) is an important function of the stomach
Storage (has the ability to stretch)
Begins protein digestion (requires acid and pepsin): not an essential function since protein digestion also takes place in the small intestine
Secretion of Intrinsic Factor that is required for absorption of vitamin B12
Some absorption of glucose and many drugs occurs, but the stomach is not specialized for absorption |
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Term
| What 4 things do the gastric glands secrete? |
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Definition
Pepsinogen: (Chief Cells) that is converted to the proteolytic enzyme Pepsin by HCL
HCl: Acidifies pH/Activates Pepsin (Parietal Cells).
Mucus: Protective Alkaline Secretion (Goblet Cells).
Intrinsic Factor: Aids In B12 Absorption (Parietal Cells). |
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Term
| Describe the regulation of gastric secretions (4) |
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Definition
Parasympathetic Stimulation promotes some release of acid by parietal cells during the cephalic phase and local enteric stimulation in response to stomach stretching during the gastric phase
Gastrin (more important): Stimulates secretion of pepsinogen and HCl in response to protein and low [H+].
Histamine: Stimulates Gastric Secretion in response to gastrin.
Parietal cell response is greatest when gastrin and histamine and neural stimulation occur together |
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Term
| What three features make for the resistance of gastric mucosa to HCl? |
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Definition
1. Stomach Epithelium Is Covered By Alkaline Mucus.
2. Epithelial Cells Of The Mucosa Are Connected By Tight Junctions.
3. Epithelial Cells Are Replaced Very Rapidly. |
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Term
| What two things will mucosal damage cause? |
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Definition
| Acute Gastritis and Peptic Ulcers |
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Term
| Define and describe gastric motility (5) |
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Definition
Waves of activity that create a churning type motion towards the pyloric sphincter. Very important for mechanical digestion, and the force of contraction determines the rate of gastric emptying.
Contractions occur at a constant rate that is dependent on Pacemakers in the smooth muscle.
Contraction force is regulated by neural and hormonal reflexes.
Gastric Motility is increased by the Parasympathetic Nervous System and local enteric neural response to stretch (cephalic and gastric phases)
Motility is decreased during the intestinal phase by neural and hormonal (e.g. Secretin and CCK) reflexes in response to activation of stretch and chemoreceptors in the small intestine |
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Term
| What are three segments and three functions of the small intestine? |
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Definition
Duodenum: short uncoiled segment
Jejunum
Ileum
Functions:
1. Completion of chyme digestion.
2. Absorption of Nutrients and H2O.
3. Transport of residue to the large Intestine. |
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Term
| What three structures increase the surface area of the small intestine? |
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Definition
Plicae Circularis (circular folds)
Villi
Microvilli on Simple Columnar Epithelium |
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Term
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Definition
| The lymphatic vessels (capillaries) of the small intestine that absorb digested fats |
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Term
| What are the two secretory structures of the small intestine wall? |
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Definition
| Mucus Glands And Goblet Cells |
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Term
| What two enzymes digest nucleic acids? |
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Definition
| Nucleosidases and Phosphatases |
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Term
| What two enzymes are responsible for glucose oligosaccharide digestion? |
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Definition
| Dextrinase and Glucoamylase |
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Term
| What things constitute pancreatic juice? (8) |
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Definition
1. HCO3- Neutralizes Chyme.
2. Pancreatic Enzymes (Digestion).
Amylase.
Lipase.
Proteases:
Trypsin.
Chymotrypsin.
Carboxypeptidase.
Nuclease. |
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Term
| Describe the roles of secretin and cholecystokinin |
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Definition
Secretin From The Duodenum; Stimulates The Release Of Pancreatic Juice That Is Mostly H2O and HCO3-
Cholecystokinin From The Intestinal Wall; Stimulates The Release Of Pancreatic Juice With A High Concentration Of Enzymes; Regulates Bile Release via Gall Bladder Contraction |
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Term
| What 4 things constitute bile salts? |
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Definition
| Bile Pigments, Cholesterol, H2O, and Electrolytes |
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Term
| How are monosaccharides absorbed? AAs? electrolytes (Na, Ca, Fe)? H2O? FAs? |
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Definition
Monosaccharides: Into Blood by Carrier Mediated Diffusion (Fructose) And Secondary Active Transport (Glucose and Galactose).
Amino Acids (fig 23.34): Transported into Blood by secondary active transport.
Electrolytes: Diffusion and Active Transport Into Blood.
Active Ca+2 absorption is regulated by vitamin D
Sodium Absorption can also be stimulated by hormones
Iron is actively transported and is stored in the epithelium bound to ferritin. Iron release into the blood from intestinal cells is regulated
H2O: Osmosis into Blood. Dependent on the active transport of nutrients and electrolytes (most importantly Na+)
Fatty Acids And Glycerol:
Diffuse Through Cell Membranes.
Short Chain Fatty Acids Are absorbed Into Blood.
Long Chain Fatty Acids Are Used To Re-synthesize Fats That Form Chylomicrons that Are absorbed Into Lymph via Lacteals. |
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Term
| Describe the absorption of vitamins (3) |
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Definition
Fat soluble vitamins become dissolved in dietary fat and are absorbed by diffusion
Most water soluble vitamins are also absorbed by carrier mediated transport
Vitamin B12 is large and requires intrinsic factor. When complexed with intrinsic factor, B12 is absorbed from the ileum by endocytosis |
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Term
| Where are bile salts reabsorbed? |
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Definition
| They are absorbed back into the blood in the ileum |
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Term
| Define segmentation contractions |
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Definition
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Term
| What are the segments of the large intestine? (6) |
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Definition
| Cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum |
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Term
| What are the three functions of the large intestine? |
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Definition
No Digestion!
1. Absorption of H2O And Electrolytes In The Proximal Half.
2. Forms and Stores Feces.
3. Contains Bacteria That Use Cellulose in The Feces For Energy And Produce Vitamins (e.g Vitamin K and B vitamins that are absorbed from the large intestines into the blood) |
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Term
| What is the structure of the walls of the large intestine? |
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Definition
| Lacks Villi and the Mucosa Appears Flat and contains a large number of glands that secrete mucus |
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Term
| When does the large intestine secrete mucus? |
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Definition
| In Response To Mechanical Stimulation |
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Term
| How often does peristalsis occur? |
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Definition
|
|
Term
| Describe the defecation reflex (5) |
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Definition
1. Initiated By Passage Of Feces Into Rectum Increasing The Rectal Pressure.
2. Peristaltic Waves Are Initiated.
3. Internal Anal Sphincter Is Relaxed; Feces Enter Anal Canal.
4. Defecation Does Not Occur Until The External Anal Sphincter Is Relaxed Voluntarily.
5. Defecation Is Aided By Contraction Of Longitudinal Muscles; And Contraction Of Abdominal And Pelvic Muscles. |
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Term
| Anatomically describe the liver (6) |
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Definition
Liver lobules: six sided structure that consists of plates of hepatocytes
Central vein
Portal triad: branches of the hepatic artery, hepatic portal vein, and bile duct
Liver sinusoids: very permeable capillaries separating plates of hepatocytes
Kupffer cells (macrophages) line the sinusoids
Bile canaliculi: small channels for bile between hepatocytes |
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Term
| List the 7 functions of the liver we must know |
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Definition
1. Synthesis of Bile for Fat Digestion
2. Endocrine Functions
3. Synthesizes Clotting Factors and Plasma Proteins
4. Metabolic Functions Involving Carbohydrates, Fats and Proteins
5. Storage of Glycogen, Vitamins and Blood
6. Filters Blood; Removes Damaged Red Cells And Foreign Substances
7. Breaks Down Toxic Compounds |
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Term
| Describe the inverse relationship between changes in pressure and changes in volume (Boyles Law) |
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Definition
pV = k
p denotes the pressure of the system.
V denotes the volume of the gas.
k is a constant value representative of the pressure and volume of the system. |
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Term
| Describe the mechanism of creating pressure gradients for inflow and outflow of air (i.e. pulmonary ventilation) |
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Definition
Flexion of the diaphragm and intercostal muscles allows for inflow of air as the volume of the lungs increases causing a decrease in the volume.
Cartilaginous structure of the rib cage decreases volume, increasing pressure in the reverse direction of the inflow. |
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Term
| Define transpulmonary pressure |
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Definition
| Pressure difference between alveoli and pleural fluid |
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Term
| Describe the role of carbonic anhydrase in the bicarbonate/CO2 equilibrium |
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Definition
| Speeds up CO2 + H2O ←→ HCO3- + H+ |
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Term
| Describe the enteric nervous system and the significance of the enteric nervous system in local regulation of digestion (3) |
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Definition
Digestion will slow but still occur due to smooth muscle pacemaker cells (as part of local control), regulate contraction and prevent excessively quick movement of food through digestive system. (constitutes “belly brain”)
Gastric Motility is increased by the Parasympathetic Nervous System and local enteric neural response to stretch (cephalic and gastric phases)
Important to peristalsis |
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Term
| What are the functions of bile? (2) |
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Definition
Neutralize chyme from stomach
Emulsification of fats |
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Term
| What determines how much HCl is released in the stomach? |
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Definition
| HCl release is proportional to protein presence |
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Term
| What are the two pleural membranes? |
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Definition
| Visceral and parietal layer (P on inside, V on outside) |
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Term
Define intrapleural and intrapulmonary/alveolar pressure
How are these terms related? (2) |
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Definition
Alveolar (intrapulmonary) = pressure in the lungs
Intrapleural pressure= pressure outside the lungs.
If there is a difference between the alveolar and intraplearal there will be inflow or outflow.
The inverse relationship of these pressures keeps air in the lungs and thus keeps them from collapsing. |
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Term
| Distinguish the passive mechanism for expiration during normal breathing at rest and the mechanism for forced expiration |
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Definition
Normal breathing is the tidal volume.
Diaphragmatic relaxation leads to exhalation.
Elastic tissue→ elastic recoil→ exhale
Forced exhalation involves intercostals to exhale. |
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Term
| Describe the relationship between compliance and pulmonary ventilation |
|
Definition
Compliance - the ability of the lungs to stretch during a change in volume relative to an applied change in pressure
Decreased compliance increases the muscle effort required during inspiration (pulmonary ventilation) |
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Term
| Describe how alveolar ventilation is controlled (include the controlled variables, receptors, integrating center and effectors) |
|
Definition
Control variable CO2, H+
and less importantly O2
Receptors chemoreceptors
Integrating center= medulla/ pons
Effectors diaphragm, muscles, pulmonary respiration |
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