Lab 6 - Digestion

Question 1

Avg. BP at: systemic circulation

1. Left ventricle
2. Aorta
3. Large arteries
4. End of arteries
5. Arterial end of capillarries
6. Venous end of capillaries
7. Large veins
8. Right atrium

Answer 1

1. Left ventricle: 120/8 mmHg
2. Aorta: 120/75 mmHg
3. Large arteries: 135/68 mmHg
4. End of arteries: 98/68 mmHg
5. Arterial end of capillaries: 32 mmHg
6. Venous end of capillaries: 10 mmHg
7. Large veins: 2-5 mmHg
8. Right atrium: 3 mmHg

Question 2

Avg. BP at: pulmonary circulation

1. Right ventricle
2. Pulmonary artery
3. Lung capillaries
4. Left atrium

Answer 2

Avg. BP at: pulmonary circulation

1. Right ventricle: 25/0 mmHg
2. Pulmonary artery: 23/9 mmHg
3. Lung capillaries: 8mmHg
4. Left atrium: 6 mmHg

Question 3

Pulse wave velocity

Answer 3

7 m/sec

Question 4

Blood flow velocity

1. Aorta
2. Large veins
3. Capillaries

Answer 4

1. Aorta: 30-40 cm/sec
2. Large veins: 15-20 cm/sec
3. Capillaries: 0.05 cm/sec

Question 5

What is the mixed content of the stomach called?

Answer 5

Chymus

Question 6

What substances taste salty?

Answer 6

neutral salts of strong acids and bases

Question 7

Histamine acts on which receptors?

Answer 7

H2 receptors

Question 8

What effect has verapamil?

Answer 8

Ca2+ channel inhibitor

Question 9

What is involved in the taste pathway?

Answer 9

Fascial (VII), glossopharyngeal (IX) and vagus (X)

Question 10

The mixture of food structure resembles what?

Answer 10

onion

Question 11

Where in gastrointestinal tract does ptyalin act?

Answer 11

in the stomach

Question 12

What substance act on parietal cells?

Answer 12

Acetylcholine, Histamine and Gastrin

Question 13

In which way does verapamil inhibit muscle contraction?

Answer 13

Ca2+ channel inhibition

Question 14

Which cells does gastrin have effect on?

Answer 14

parietal cells

Question 15

Where can you find the food eaten last?

Answer 15

in the cardia

Question 16

How to measure the basal HCl cons.?

Answer 16

by titrating 0.01 M NaOH, after adding phenolphtalein

Question 17

What dissociates the actomyosin complex?

Answer 17

myosin phosphatase (MP) enzyme

Question 18

Examples of sour taste?

Answer 18

hydrogen ion dissociating molecules – buffers of saliva alters sensation

Question 19

Examples of bitter taste?

Answer 19

several alkaloids: strychnine, quinine, several glycosides, ethers, some Mg2+ and Ca2+ salts, ammonium compound and sulphates

Question 20

What is ED50?

Answer 20

Active ingredient concentration needed for half maximal muscle contraction

Question 21

What pathway does muscarinic Ach receptors activate?

Answer 21

G-protein phospholipase C pathway

Question 22

What enzyme initiates SM contraction?

Answer 22

MLCK = Myosin Light Chain Kinase

Question 23

Which gastric juice producing cells are influenced by Acetycholine?

Answer 23

Parietal Cells

Question 24

Effects of acetylcholine is mediated by which type of receptors?

Answer 24

Type M(3) muscarinic Ach receptors

Question 25

Which effect has acetylcholine on gastric SM?

Answer 25

stimulating

Question 26

By which cells and where is gastric juice secreted?

Answer 26

By chief (peptic) and parietal cells in the fundus region of the gastric mucosa

Question 27

What does the gastric juice cells produce?

Answer 27

- Parietal cells: HCl | - Chief cells: pepsinogen

Question 28

What does the acetylcholine released from cholinergic postganglionic neurons stimulate?

Answer 28

Parietal, ECL cells and furthermore G cells

Question 29

What is histamine produced from?

Answer 29

ECL cells

Question 30

What is histamine production regulated by?

Answer 30

Gastrin and vagus nerve

Question 31

What and where is Gastrin secreted by?

Answer 31

G cells in the antrum region

Question 32

What does Gastin increase the secretion of?

Answer 32

HCl secretion

Question 33

What is the function of G cells regulated by?

Answer 33

Vagus nerve and gastric pH

Question 34

What effect has acetylcholine?

Answer 34

Parasympathicomyemetic - stimulating

Question 35

Which effect has atropine?

Answer 35

Parasympathicolytic - inhibition

Question 36

Which effect has norepinephrine?

Answer 36

Sympaticomymetic - sphincter: constriction, elsewhere: relaxation

Question 37

Which effect has verapamil?

Answer 37

Ca2+ channel inhibition - inhibition

Question 38

What is spike potentials?

Answer 38

Action potentials in the smooth muscle cells

Question 39

What is the frequency of contractions of GI tract determined by?

Answer 39

Slow waves (continuous change in the membrane potential of smooth muscle cells)

Question 40

What is competitive antagonism?

Answer 40

The transmitter (agonist) and the antagonist compete for the same binding sites

Question 41

How can the binding of the antagonist be eliminated?

Answer 41

By increasing the concentration of the agonist

Question 42

Which receptor does atropine inhibit?

Answer 42

Muscarinic Ach receptors

Question 43

Which roles does the sensation of taste have?

Answer 43

Food checking, inducing saliva and gastric juice production, etc.

Question 44

Examples of sweet taste?

Answer 44

Sugars, e.g. saccharine, saccharose