quiz 9 Flashcards
1
Q
what causes swelling/edema?
A
- swelling/edema caused by extra fluid in interstitial space
- common reasons:
- vascular damage (leaking)
- increased hydrostatic pressure (damage to area causes greater flow)
2
Q
where and what is the lymphatic system?
A
- follows along cardiovascular system; “second circulatory system”
- delivers excess water in interstitial space back to circulatory system
3
Q
what is the primary driver of water movement across capillaries?
A
- vascular hydrostatic/osmotic pressure is main driver (high hydrostatic at start; high osmotic at end)
- interstitial pressures have only slight impact
4
Q
classification of digestive systems based on what organisms eat
A
- herbivore
- carnivore
- omnivore
5
Q
monogastric vs polygastric
A
- carnivores and omnivores (and a few herbivores) are monogastric
- one “true stomach” with acid and pepsin enzymes for digestion
- herbivores are polygastric
- highly specialized stomach components
6
Q
role of true stomach, small intestine, and large intestine
A
true stomach: secretes enzymes for digestion
small intestine: absorption of nutrients
large intestine: absorption of water; some nutrients
7
Q
what organisms can digest cellulose?
A
- no carnivores
- some omnivores
- all herbivores
8
Q
herbivore digestive tract
A
- herbivores have the longest digestive tracts because they are ruminant animals
- the materials they consume take longer to digest before they can be assimilated
9
Q
differences in dentition between animals
A
- herbivores have flat teeth for grinding
- carnivores have large/sharp teeth for ripping/tearing/cutting
- omnivores have “leatherman” teeth that are multipurpose
10
Q
how do we prevent food from being inhaled
A
- epiglottis is a flap of tissue that closes the trachea while we swallow, preventing aspiration
11
Q
role of salivary glands
A
- salivary glands release saliva to lubricate food during mastication
- contain amylase to begin digesting carbs but overall little enzymatic activity
12
Q
peristalsis
A
enteric nervous system controls peristalsis movement of bolus down the esophagus
- circular muscles contract behind food mass
- longitudinal muscles contract ahead of food mass, shortening the tube in front of the mass
- circular muscles contract to move bolus forward
13
Q
*** esophageal problems with age
A
upper esophageal sphincter: trouble swallowing (opening/closing epiglottis)
lower esophageal sphincter: GERD
14
Q
what is GERD? what problems does it cause? solutions?
A
- gastroesophageal reflux disease
- lower esophageal sphincter gets acidic as stomach acid sloshes up
- continued acid washing increases risk of esophageal cancer
- solution: proton pump inhibitors reduce stomach acidity, but reduces pepsin (it needs low pH to activate)
15
Q
stomach anatomy
A
- fundus at the top
- body in the middle
- antrum and them pylorus at the bottom
- lumen is made up of gastric glands which have many cell types!
16
Q
cells in gastric glands
A
- goblet cells: at top; bicarbonate-rich mucus protects stomach lining from acid
- parietal cells: gastric acid production by proton pumps (active)
- chief cells: produce pepsinogen (protease precursor)
- D cells and G cells: regular acid secretion
17
Q
importance of acid production in the stomach
A
- kills bacteria
- gastric juice pH in humans is 2, in some carnivores like vultures it’s 1
- carnivorous birds spit up acidic stomach contents onto talons before feeding on decaying flash, pre-sterilizing them from bacteria
18
Q
protein digestion in the stomach
A
- chief cells produce pepsinogen, an inactive protease precursor
- pH in stomach turns pepsinogen into pepsin, which partially digests proteins into small peptide fragments
- important to use inactive precursors because they can be stored/secreted without breaking down proteins in the secretory cell
19
Q
what is food called in the esophagus vs stomach
A
esophagus: bolus
stomach: chyme
20
Q
functions of the pancreas
A
endocrine functions:
- release insulin from beta cells
- release glucagon from alpha cells
exocrine functions:
- acinar cells release bicarbonate and proteases to duodenum
21
Q
endocrine vs exocrine
A
endocrine: release hormones to the bloodstream
exocrine: release material to small intestine lumen via a duct
22
Q
exocrine role of the pancreas
A
acidic chyme from the stomach must be neutralized in the duodenum
- low pH stimulates secretin from duodenum cells, which signals acinar cells in pancreas release bicarbonate (base) to neutralize pH
- lipids/fats induce release of cholecystokin (CCK) from duodenum cells which signals release of digestive enzymes (including trypsinogen)
23
Q
role of trypsinogen
A
- inactive precursor to a protease released by acinar cells (in response to CCK)
- enzymes in duodenum lining convert it to trypsin
- trypsin activates other inactive precursors for protein digestion (cascade)
*important because more gut absorption is in the duodenum!
24
Q
role of bile in the duodenum
A
- bile produced by the liver, stored by the gall bladder
- emulsifies fats (with the help of pancreatic lipase)
- CCK secretion by duodenum (response to fats in chyme) induces release of bile by causing the gall bladder to contract
25
upper GI tract anatomy
- uvula: blocks off nasopharynx
- nasopharynx
- oropharynx
- laryngopharynx
- epiglottis: covers trachea when swallowing
- salivary glands: parotid, submandibular, sublingual
- upper esophageal sphincter
26
esophageal anatomy
- circular and longitudinal muscles
- enteric nervous system controls peristalsis
- lower esophageal sphincter
27
how does bile work on fats?
- bile emulsifies fats with the help of pancreatic lipase
- fats enter duodenum as triglycerides, broken down into monoglycerides and fatty acids
- mix of fats form small droplets called micelles to be absorbed
28
functions of the large intestine
- absorb water and salts
- produce and absorb vitamins
- form/propel feces
29
how are different substances absorbed in the small intestine?
- fatty acids and micelles: simple diffusion
- water: osmosis; through aquaporins
- glucose and fructose: SGLT (with sodium) or GluT transporters; both facilitated diffusion
- amino acids or di/tripeptides: active transport
30
problems with long-term asprin use
- asprin increases acid production from parietal cells and decreases bicarbonate production in mucus layer
- stomach relies on bicarbonate-rich mucus to keep pH 2 away from stomach lining
- long-term asprin use erodes the mucus layer, leading to gastric ulcers
31
how do our carbohydrate levels fluctuate?
- blood glucose levels vary, but the body attempts to maintain a stable blood glucose level between meals
- absorption of glucose from food raises it, glucose must exit the bloodstream and enter cells to lower it
32
role of insulin
- high blood glucose after meals promotes the release of insulin
- beta cells in pancreas are always sensing glucose levels; in response to high blood glucose they release insulin which has 2 roles:
* stimulate glucose uptake from blood to cells (triggers reservoir of glucose channels to be put in cell membranes)
* triggers glycogen formation in the liver
33
binding of insulin ***
- binds to tyrosine kinase receptors, causing them to dimerize (pair)
- dimerization triggers auto-phosphorylation of kinases (using ATP) which can then phosphorylate more receptors or protein targets (kinase activity)
34
what are kinases?
enzymes that allow you to phosphorylate a target
35
what does insulin binding do to the cell? (pathway) ***
- insulin binds to tyrosine kinase receptors, activating them to phosphorylate things
- phosphorylation leads to activation of many signaling molecules, which cause different processes
* anabolic events like protein synthesis
* GLUT4 transporters sent to membrane to bring in glucose
36
what happens to glucose after entering the cell?
- can be burned or stored as glycogen
- osmotic load of cell is reduced when its stored as glycogen compared to glucose (only 1 molecule); stored this way so the cell isn't fighting the inward movement of water
37
role of glucagon
- helps regulate blood glucose between meals
- produced by alpha cells in the pancreas; induces glucose release from glycogen stores in the liver
- liver is the only organ that can release glucose into the blood!!
- small amount of insulin also released (needed for glucose uptake into cells)
