Lecture 19

Question 1

What are the 4 basic process in digestion?

Answer 1

Digestion

Motility

Secretion

Absorption

Question 2

What occurs in digestion?

Answer 2

The break down of large food pieces into small molecules by mechanical or chemical methods

Question 3

What occurs during motility in digestion?

Answer 3

The mixing (churning) and movement through GI tract

Question 4

What is another term for moving food through the body?

Answer 4

Peristalsis

Question 5

What occurs during secretion in digestion?

Answer 5

Digestive juice into lumen of IG tract to break down molecules and kill bacteria

Question 6

What are the 2 enzymes in the mouth? And what do each break down?

Answer 6

Lingual lipase -> triglycerides to fatty acids

Salivary amylase -> carbs/glycogen/ starch to disaccharides

Question 7

Does absorption occur in the mouth?

Answer 7

No.

Maybe some drugs

Question 8

What are the 3 phases during swallowing?

Answer 8

Buccal phase - food into bolts and moved back of mouth while uvula prevents food going into nose (voluntary)

Pharyngeal phase - tongue does a body roll to throw it back while epiglottis covers trachea

Esophageal phase - bolus moves down esophagus by peristalsis

Question 9

What innervates each divisions of the esophagus?

Answer 9

Upper 1/3 somatic neurons - skeletal muscle

Middle 1/3 mix of skeletal and smooth muscle

Lower 1/3 PSNS neurons - smooth muscle

Question 10

What are the 2 sphincters to enter and exit the stomach?

Answer 10

Esophageal sphincter

Pyloric sphincter

Question 11

What occurs in the stomach during digestion?

Answer 11

Chemical digestion - Salivary amylase, lingual lipase, gastric lipase continues to break down till pH goes below 5- 6

Mechanical digestion - muscular, circular and oblique muscle layers churns food

Drugs and alcohol is absorbed

Question 12

How is chyme transitioned to small intestine?

Answer 12

By the pyloric sphincter letting small amount of chyme enter and neutralize acidity with secretin and Chloe from pancreas and gallbladder

Question 13

What proteins does the pancreas release?

Answer 13

Trypsin, chyme trypsin, carboxypeptidase

Question 14

What induces the secretion of Chloe from the pancreas?

Answer 14

Amino acids and fatty acids which will cause more secretion of pancreas enzyme -> more gallbladder -> lower gastric motiloity and secretion

Question 15

What enzyme are present in the intestine?

Answer 15

Sucrase, maltase, lactase, aminopeptidases

Question 16

What molecule is not digested in the intestine?

Answer 16

Lipids

Question 17

What is the small intestine known for?

Answer 17

The main site of absorption due to the folds in the villi making the surface area greater

Question 18

Where do the absorbed nutrients go after small intestine?

Answer 18

Liver via the hepatic vein

Lacteals/ lymphatic vessels (lipids)

Question 19

Where do lipids go after getting absorbed by the lymphatic system?

Answer 19

Via thoracic duct empties into leftsubclavian vein

Question 20

How is fat digested and absorbed?

Answer 20

Requires bile from the liver and gallbladder to travel through hepatopancreatic duct to duodenum and enter enterocytes to be packaged as chylomicrons -> go to lymphatic vessel

Question 21

What is the composition of bile?

Answer 21

Water

Bile salts

Bile pigments

Ions

Detoxified hormone/drugs

Question 22

How does bile work?

Answer 22

Emulsifies fat - break into small droplets (like soap)

Micelle formation - keeps fat in a bubble like solution

Question 23

What are the characteristics of micelles?

Answer 23

Composed of bile salts and phospholipids

Exterior is hydrophilic - interior is hydrophobic

Question 24

What are the phases of gastric motility?

Answer 24

Cephalic phase - prepare stomach from food triggered by sight, smell, thought

Gastric phase - stimulation of secretion and motility of stomach triggered by stretch and chemo receptors

Intestinal phase - prevents tonicity of chyme from overwhelming the intestine and slow absorption/ digest -> inhibitory signal to gastric secretion

Question 25

What are the different motility types in the large intestine?

Answer 25

Haustral contractions - slow and weak contractions to move material down but allows absorption and mixing

Mass movement/ parastolysis - food ingestion sends contraction waves to transverse colon to poo

Question 26

How is defecation reflex triggered?

Answer 26

Stimulating the stretch reflex in the rectum to the sacral (S1-3 -> smooth muscle/ visceral NS) spinal cord

Contract and relax in the anal canal by sphincters

Question 27

Do we have voluntary control over defecation reflex?

Answer 27

Yes by the external anal sphincter but it can be overridden

Question 28

What digestion and secretion occurs at the large intestine?

Answer 28

No digestion

Bacteria creates vitamins

K and HCO is secreated

Question 29

What is absorbed in the large intestine?

Answer 29

400 ml of water via osmosis/ day

Drugs

Question 30

How is glucose moved from the blood to the tissue cells?

Answer 30

Via facilitated diffusion

Question 31

What percent of body energy stores does glycogen serve as?

Answer 31

1%

Question 32

What is cholesterol used to make?

Answer 32

Steroid hormones, bile and cell membranes

Question 33

How are amino acids enter a cell?

Answer 33

Facilitated diffusion or secondary active transport

Question 34

Where are amino acids stored?

Answer 34

They’re not!

Excess is converted into fat

Question 35

What is the metabolic rate?

Answer 35

The body’s rate of energy use by chemical and mechanical work

Question 36

Why is basal rate important?

Answer 36

It is the energy your body needs to perform the bare minimum (breathing, HR, kidney function)

Question 37

What are the main hormones form the stomach?

Answer 37

Gastrin - high acid/gastric enzymes (lipase and pepsinogen)

Secretin - high alkaline secretion from pancreas and gall bladder
- low gastric secreation

CCK - high pancreatic enzymes secreted
- high gall bladder contraction
- low gastric motility and secretion