GI System

Question 1

Desribe the gi tract

Answer 1

Assembly line

Question 2

List the 6 essential activities in GI

Answer 2

Ingestion
Propulsion
Mechanical digestion
Chemical digestion
Absorption
Defecation

Question 3

List the GI primary organs

Answer 3

Mouth
Pharynx
Oesophagi
Stomach
Small intestine
Large intestine

Question 4

List The GI secondary accessory

Answer 4

Teeth
Tongue
Salivary glans
Gallbladder
Liver
Pancreas

Question 5

What does an adequate diet include

Answer 5

Lipids
Carbs
Proteins
Vitamins
Minerals
Water

Question 6

Largest gland in the mouth

Answer 6

Salivary gland located anterior to ears

Question 7

Basic composition of saliva

Answer 7

Water
Salivary amylase
Muffins
Ions
Buffers

Question 8

Role of Saliva

Answer 8

Salivary amylase breaks down starch
Mucin - lubricating mouth
Moistens and converts into bouls to be easily swallowed

Question 9

What are the 3 modifications of stomach wall

Answer 9

Circular
Longitudinal
Oblique

Question 10

Role of stomach

Answer 10

Greater churning/ mixing ability
Mechanical breakdown if foodstuff into smaller pieces

Question 11

Define mucus

Answer 11

Glycoprotein in stomach used for lubrication

Question 12

Explain role of bicatbonate

Answer 12

Generates ph gradient to protect stomach wall from digestion by gastric acid

Question 13

Recall:
Where is mucus secreted, stimulus release and function

Answer 13

Source: mucous neck cell
Sfr- tonic secretion, increasing with stomach irritation
Function- physical barrier between lumen and epithelium

Question 14

Recall-
Source of secretion for bicarbonate with stimuli for release and function

Answer 14

Source- mucous neck cell
Sfr- secreted with mucous
Function- buffers gastric acid to prevent damage to epithelium

Question 15

Recall-
Source of secretion for HCl, stimuli for release and function

Answer 15

Source - parietal cells
Sfr- ACh, gastrin, histamine
Function- activates pepsin and kills bacteria

Question 16

Recall-
Source of secretion for intrinsic factor, stimulus for release and function

Answer 16

Source- parietal cells
Sfr- ACH, Gastrin, Histamine
Function- binds to b12 to permit absorption

Question 17

Recall
Source of histamin
/ Stimulus for Release
and function of histamine

Answer 17

Source- enterochromaffin like cells
Sfr- ACH/gastrin
Function - Stimulate gastric acid secretion

Question 18

Recalle source of pepsinogen/gastric lipase , stimuli for release and function

Answer 18

Both released by chief cells
Both stimulates byACh, acid, secretin
Pespin- proteins
Gastric lipase - fats

Question 19

Recalls source stimulation for release and function of somastatin

Answer 19

D cells source
Sfr- acind in stomach
Function- stops gastric acid secretion

Question 20

Recalls source stimulation for release and function of gastrin

Answer 20

Source - G cells
Stimuli for release a ACh peptides and amino acids
Function- stimulate gastric acid secretion

Question 21

List 3 reasons to why gastric juice does not digest stomach wall

Answer 21

Mucous barrier by epithelial cells
Alkaline mucous barrier
Tight junction between epi cells prevent acid leaking

Question 22

State turnover for GI epi cells

Answer 22

Every 3 days

Question 23

How is the Stomach Surface Area increased

Answer 23

Finger like projections called villi & invaginations called crypts

Question 24

Describe relationship between surface area and absorption

Answer 24

Increased SA= Increased absorption

Question 25

Where does absorption take place

Answer 25

Small Intest

Question 26

State what happens in the duodenum

Answer 26

Enteroendocrine cells secrete peptide bile added to chyme

Question 27

Role of the liver

Answer 27

Synthesis and secretion if bile

Question 28

What are bile salts composed of

Answer 28

Cholesterol

Question 29

Role of bile/liver

Answer 29

Emulsification of fat globules Decrease size of droplet= increase sa

Question 30

Role of gallbladder

Answer 30

Concentrates and stores bile

Question 31

When will bile be stored in gallbladder

Answer 31

When sphincter of oddi closes bile cannot enter duodenum

Question 32

Role of pancreas

Answer 32

Have acinar cells which secrete pancreatic juice into pancreatic duct containing HC03

Question 33

What is pancreatic juice made of

Answer 33

Water Organic subs Enzymes Inorganic subs

Question 34

Describe the intestinal juice

Answer 34

Neutral PH Medium for digestion and absorption Contains digestive enzymes made from epi cells in si

Question 35

How is glucose absorbed

Answer 35

Active transport

Question 36

What cannot be digestedin stomach

Answer 36

Cellulose also known as fibre

Question 37

Explain what happens to proteins

Answer 37

Broken down to dipeptides and single amino acids and join with sodium for transport

Question 38

Explain the role of emulsification in lipid digestion

Answer 38

Bile increases lipid droplets solubility and digestibility by breaking them down to smaller pieces

Question 39

What does pancreatic lipase break TAGs down into

Answer 39

2 fatty acids 1 monoglyceride

Question 40

Where do FAs rapidly absorb into

Answer 40

Portal vein

Question 41

Steps in lipid absorption

Answer 41

Emulsification Micelle formation Hydrolysis Absorption Restedification Lipoprotein formation/transport

Question 42

How do lipids reach blood stream

Answer 42

Absorbed by intestinal mucosa Broken down into chylomicrons Moved into lymphatic system Emptied in venous blood

Question 43

How and where are vitamins absorbed

Answer 43

Jejenum and ileum Passive diffusion

Question 44

What happens to vitamins once absorbed

Answer 44

Transported ti liver and fatty tissue by chylo/lips

Question 45

Explain the difference between absorption of vitamins and b12

Answer 45

Watee soluble vitamins diffuse into blood B12 remains with intrinsic factor

Question 46

Recall how b12 is absorbed

Answer 46

Remains with intrinsic factor Absorbed via endocytosis