Bio Final Exam Ii

Front 1

Define Ingestion.

Back 1

Taking food into the mouth, swallowing it, and moving it through the gastrointestinal tract.

Front 2

Digestion

Back 2

breaking down complex biomolecules into small ones mechanically (with teeth) and chemically (with enzymes and other biomolecules).

Front 3

Absorption

Back 3

The passing of small enough broken down food particles through the membranes of the epithelial cells of the digestive tract.

Front 4

Elimination

Back 4

Getting rid of waste from the blood and the intestine. Blood: waste made in the liver is eliminated through bile.
Intestine: indigestible parts of the food are removed from the body with as little waste as possible (water and bile acids are reabsorbed).

Front 5

What are the GI track organs? Accessory organs?

Back 5

Mouth >> pharynx >> esophagus >> stomach >> small intestine >> large intestine >> rectum >> anus
Accessory organs: salivary glands, liver, gall bladder, pancreas

Front 6

Mucosa

Back 6

1st innermost layer of tissue in GI track.
- Epithelial cell layer (of endothelial cell)
- Secretes necessary biomolecules for digestion
- absorbs digested particles
- epithelial cell function changes along the GI track

Front 7

Submucosa

Back 7

Connective tissue supporting the overlying epithelium.
Contains blood vessels which supply GI track with oxygen and nutrients and transports nutrients.
Contains nervous tissue with sensory and secretory functions.

Front 8

Muscularis

Back 8

Mostly smooth muscle arranged circularly and longitudinally.
Contraction causes movement of food (peristalsis)
Muscular sphincters can stop movement.
Has nervous tissue (ENS) that help control contractions and can act independently from CNS

Front 9

Peritoneum

Back 9

Outermost CT layer which attached the GI to the rest of the body.
Has epithelial tissue as well which secretes fluid that results in friction.

Front 10

Describe surface area of GI tissue

Back 10

Has villa and folding because it needs increased surface area for its function of absorption.

Front 11

Define peristalsis

Back 11

The movement of the GI due to longitudinal muscles (shorten and extend) and circular muscles (compress lumen).

Front 12

Enteric Nervous System

Back 12

Nerves entirely within a nerve net.
Acts independently of CNS.
Smooth muscles can contract and secrete.

Front 13

Describe the mouth.

Back 13

Mechanical and chemical breakdown of food.
Mechanical = by differentiated teeth and by tongue.
Chemical = Salivary Amylase (enzyme, starts in mouth to digests sugars), bicarbonate (neutralizes acids in food), mucins (bind food together)

Front 14

Describe the pharynx

Back 14

The throat.
Food in mouth goes down into pharynx where swallowing occurs.

Front 15

Describe Swallowing. What is the epiglottis.

Back 15

A reflex action that propels food into the esophagus.
Action rises throat which closes larynx.
Epiglottis = covering for the glottis (opening of the wind pipe) that prevents food going into the trachea.

Front 16

Esophagus

Back 16

Muscular tube through which food moves to stomach, propelled by peristaltic contractions (series of waves)

Front 17

Stomach Structure

Back 17

J-shaped stomach.
- gastroesophageal sphincter (aka cardiac sphincter)
- pyloric sphincter

Front 18

Describe the gastroesophageal sphincter

Back 18

Muscular ring that controls movement into and out of stomach.
Relaxes when stomach fills with food.
Contracts when stomach is full (limits input)

Front 19

Pyloric sphincter

Back 19

2nd muscular ring of stomach.
Relaxes as stomach fills with food.
Contracts when a strong peristaltic wave moves toward it. (limits the amount of food entering the small intestine at once)

Front 20

Stomach Function

Back 20

Storage site for food (stretches)
Mixes food into chyme.
Continues digestive process.
- protein digestion begins
- carbohydrate digestion continues

Front 21

define chyme

Back 21

a semi-solid paste from bolus and gastric juices

Front 22

What is absorbed in the stomach?

Back 22

no absorption takes place in the stomach except for alcohol.

Front 23

Three main gastric secretions of the stomach

Back 23

-Hydrochloric Acid (HCl)
-Pepsinogen
-Muscus

Front 24

Describe HCl in stomach

Back 24

- hydrolyzes chemical bonds and activates pepsinogen
- secreted by parietal cells of the mucosa
- Acidity requires stomach lining to be replaced about every three days.

Front 25

What causes ulcers?

Back 25

usually caused by bacterial infections in the stomach and not HCl

Front 26

Pepsinogen in Stomach

Back 26

pepsin=active form
enzyme that digests protein

Front 27

Mucus in stomach

Back 27

Lubricates stomach lining, protecting it from acid.

Front 28

Intestine structure

Back 28

duodenum
Jejunum
Ileum

Front 29

Duodenum

Back 29

-beginning of small intestine
-site of secretion of pancreatic juices and bile from GB
-part of the small intestine that is hit by gastric juices (acidity causes damage>>common peptic ulcer)

Front 30

Jejunum

Back 30

Upper 40% of the small intestine below the duodenum.

Front 31

Ileum

Back 31

Lower part of the small intestine.

Front 32

Function of the intestine

Back 32

- Primary site of absorption.
- where the accessory organs secrete their products
- where lipid digestion begins
- where most digestion is completed

Front 33

Describe the mucosal lining of the intestine.

Back 33

- highly folded villi
- epithelial cells have projections called microvilli
- Cholecystokinin (CCK) hormone is released from the intestinal mucosal cells and stimulates the release of bile and pancreatic juices.

Front 34

Villi

Back 34

Highly folded tissue that increases the surface area for absorbtion found on the mucosa tissue layer.

Front 35

Microvilli

Back 35

Projections of the epithelial cells of the mucosa tissue layer that increase surface area.

Front 36

Digestive Juices in the lining of the small intestine

Back 36

- disaccharidase
- aminopeptidase
- intestinal nucleases

Front 37

pancreas

Back 37

gland surrounding the small intestine

Front 38

digestive juices of the pancreas

Back 38

- secretes bicarbonate which reduced gastric acidity
- makes hormones (insulin and glucagon)
- secretes enzymes including pancreatic amylase, trypsin and chymotrypsin, carboxypeptidase, pancreatic nucleases and lipase.

Front 39

Does digestion occur in the pancreas?

Back 39

NO!

Front 40

define bile

Back 40

- yellowish brown or green material
- helps break down lipids (fats) into small enough molecules for absorption
- made by the liver and stored in the gall bladder

Front 41

Where does fat absorption and digestion occur?

Back 41

intestine

Front 42

How is fat digested?

Back 42

- occurs in the intestine
- bile dissolves fat droplets into micelles which can be digested into fatty acids and monoglyceride by pancreatic lipase.
(emulsifies fat into micelles making it easier to breakdown by lipases)

Front 43

What does it mean to say that bile is hydrophobic?

Back 43

- repels water
- can dissolve lipids (also hydrophobic) because "like dissolves like"

Front 44

Structure of the large intestine

Back 44

- cecum: pouch at the beginning of the large intestine
- ascending, transversing and descending colon (aka rectum).
- appendix: slender projection from pouch (no known digestive function)

Front 45

Function of the large intestine

Back 45

- absorbs almost all water, sodium and bile (recycles)
- concentrates and stores fecal material (unwanted or undigestable waste)

Front 46

Describe gastrin

Back 46

- gastrin is secreted from the mucosal cells into the blood
- stretching of the stomach stimulates secretion
- gastrin stimulates the release of pepsin and HCl and an increase in stomach contractions (negative feedback)

Front 47

Describe Cholecystokinin (CCK)

Back 47

- released from the intestinal mucosa
- stimulates the release of bile and pancreatic enzymes
- decreases churning (negative feedback)

Front 48

Describe Secretin

Back 48

- released by the intestinal mucosa
- stimulates the release of pancreatic bicarbonate which neutralizes HCl
- decreases churning (negative feedback)

Front 49

What is heartburn?

Back 49

- gastric jucies break up into esophagus and causes damage

Front 50

How do tums work?

Back 50

- Tums is made of calcium carbonate that breaks down into ions when it gets into stomach. (Ca2+ and CO3-)
- CO3- binds to the H+ (that's creating the acidity)
- creates more water molecules and CO2 which decreases acidity
H2CO3 --> H20 + CO2

Front 51

How does Prilosec OTC work?

Back 51

- Parietal cells in stomach release HCl and protein pumps build up acidity
- Prilosec OTC is a pump inhibitor (stops the pumps to reduce acidity

Front 52

Hydrolytic enzymes

Back 52

- break down protein, carbohydrate, and fat macromolecules into their simplest monomeric units.