Lecture 11

Question 1

What are the 2 things essential physiological processes require?

Answer 1

Energy, raw materials.

Question 2

What can autotrophs and heterotrophs subsist on?

Answer 2

Aututrophs - inorganic nutrients alone.

Heterotrophs - complex organic compounds from other organisms.

Question 3

What 6 nutrients are required?

Answer 3

Carbohydrates, lipids, proteins, vitamins, inorganic salts, water.

Question 4

How much energy is released by protein, lipids and carbohydrates per gram?

Answer 4

Carbohydrates: 17kJ/g.
Lipids: 22 kJ/g.
Proteins: 39kJ/g.

Question 5

5 functions of water?

Answer 5

Solvent, transportation, hydrostatic support (e.g. eyeball), evaporative cooling, cleaning agent (e.g. eyes).

Question 6

What are the 8 essential amino acids that must be obtained from food?

Answer 6

Trp, Met, Val, Thr, Phe, Leu, Ile, Lys.

Question 7

How much energy (x10^6J/day) is required for light work (woman), light work (man), medium work (man) and heavy work (man)?

Answer 7

8. 5,
9. 5
10. 3
11. 9

Question 8

How many calories is 1 joule?

Answer 8

0.239 calories.

Question 9

How much water is lost per day? (and therefore must be consumed)

Answer 9

2.5l.

Question 10

How long is the GI tract?

Answer 10

4.5m.

Question 11

What 3 basic digestive processes occur in the GI tract?

Answer 11

digestion, absorption, motility.

Question 12

What word describes the way muscle moves food along GI tract?

Answer 12

Peristaltic.

Question 13

What digestive process occurs in Accessory glands?

Answer 13

Secretion.

Question 14

What 4 glands make up accessory glands?

Answer 14

Salivary glands, pancreas, liver, gall bladder.

Question 15

What are the 8 digestive organs that food passes through in the digestive system?

Answer 15

Mouth, pharynx, oesophagus, stomach, small intestine, colon, rectum, anus.

Question 16

Three functions of the mouth in digestion?

Answer 16

Mechanical breakdown,
Mixing food with saliva,
Initiation of chemical digestion of carbohydrates by salivary amylase.

Question 17

4 layers of GI tract surrounding the lumen, from inside to outside.

Answer 17

Mucosa, submucosa, muscularis(circular layer, longitudinal layer), serosa.

Question 18

What 3 layers is the mucosa made of?

Answer 18

Mucous membrane,
Lamina propria, (CT, capillaries, nerves, lymphoid tissue),
Muscularis mucosae.

Question 19

What is the submucosa made of?

Answer 19

connective tissue, blood, lymphatic vessels.

Question 20

What is the series made up of?

Answer 20

Connective tissue.

Question 21

What layers of the GI tract does the nerve plexus span?

Answer 21

Submucosa to serosa.

Question 22

What are the epithelial cells in mucous membrane of mucosa called?

Answer 22

Absorptive cells, exocrine cells, goblet cells, endocrine cells.

Question 23

What are the 3 salivary glands?

Answer 23

parotid gland, sublingual gland, submandibular gland.

Question 24

How much saliva is secreted by salivary glands per minute?

Answer 24

0.5ml/min.

Question 25

What 2 enzymes are secreted by the salivary glands?

Answer 25

Salivary amylase, lingual lipase.

Question 26

What does salivary amylase digest?

Answer 26

Glycogen and starch.

Question 27

What are the 6 other functions of saliva (apart from digestion)?

Answer 27

``` Lubrication, Buffering and diluting noxious substances, Antibiotic action, Taste, Clean teeth, Fluoride, calcium uptake into teeth. ```

Question 28

How long is the oesophagus, and what type of muscle does it consist of?

Answer 28

25cm long. | Upper 1/3rd skeletal muscle, lower 2/3rds smooth muscle.

Question 29

What does the oesophagus connect?

Answer 29

Pharynx to stomach.

Question 30

Which sphincters are usually closed in the oesophagus?

Answer 30

Upper and lower oesophageal sphincters.

Question 31

What causes heartburn?

Answer 31

Back flow up oesophageal sphincters.

Question 32

What is the stomach's minimum and maximum volumes roughly?

Answer 32

~50mls to 1-2 litres.

Question 33

What cells do gastric glands in the stomach contain, and what do they secrete?

Answer 33

Parietal cells, (secrete HCl) | Chief cells, (secrete pepsinogen).

Question 34

How much HCl can be secreted in the stomach in one day, and at what concentration/pH?

Answer 34

2 litres HCl/day. | 10mM A.K.A pH2.

Question 35

What is a zymogen?

Answer 35

An inactive substance converted into an enzyme when activated by another enzyme.

Question 36

What's secreted from the neck cells in the stomach?

Answer 36

Mucus.

Question 37

What coagulates milk and is found in the stomach?

Answer 37

Rennin.

Question 38

What is the mechanism for gastric acid secretion?

Answer 38

H+ ions made from CO2 and water from carbonic anhydrase, actively transported into lumen in exchange for K+. Bicarbonate ions exchanged for chloride ions, diffuse into lumen. Causes accumulation of HCl in lumen.

Question 39

How is chymotripsinogen activated?

Answer 39

Tripsin converts it into π-Chymotripsin. | Chymotrypsin then converts π-chymotripsin into α-chymotrypsin, removing 2 dipeptides in the process.

Question 40

What activates pepsinogen?

Answer 40

HCl and a current pepsin, creating pepsin.

Question 41

What does pepsin do?

Answer 41

Degrade proteins into smaller polypeptides.