Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Nutritional physiology > 2. Anticipation to a meal > Flashcards

2. Anticipation to a meal Flashcards

1
Q

What defines the cephalic phase?

A

= When the food is not yet in your mouth. Anticipation of a meal, visual, olfactory (smell) and auditory senses activate several gastrointestinal organs.

NOT TASTE!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What monitors the GI responses during the cephalic phase?

A

The vagus (dorsal vagal complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mention the stimuli, transmission pathways and effector responses of during the cephalic phase.

A

Stimulus:

  1. Auditory
  2. Cognitive
  3. Visual
  4. Olfactory (smell)

Transmission pathway:
Higher brain centers -> dorsal vagal complex > increase parasympathetic outflow

Effector response
- Salivary secretion
- Gastric secretion (acid, inactive pepsinogen, intrinsic factor)
- Pancreatic enzyme secretion
- Gallbladder contraction
- Relaxation sphincter of Oddi
- Relaxation stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cephalic phase gastric acid secretory responses are dependent of..

A

Meal (self selected, regular, bland)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Gastric secretion during cephalic phase: what happens?

A
  1. DVS: release of Ach (Acetylcholine: neurotransmitter) > 1. binds chief cells of the stomach:

> release of pepsinogen in the stomach.

  1. AND: binds to receptor of other (parietial) cells,

> HCL released.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Gastric secretion during cephalic phase: what happens when there are protein that get digested by pepsin?

A
  1. Secretion GRP (Gastrin releasing peptide or just gastrin) by GRC (“ “cells) (because of oligopeptides) > released in the blood >
    back to cells on the stomach > more pepsinogen + HCL
    (positive feedback)
    see p. 11
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is pepsinogen already converted to pepsin. in the cephalic phase?

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is ghrelin and what does it do?

A

It is a hormone. The only one that stimulates the CNS to get more food intake.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When food is in the saliva, we call it..

A

bolus. When eating, we are now in the gastric phase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name some constituents in saliva and their functions

A

Mucins: lubrication
Amylase: starch digestion
Lipase: lipid digestion
Lysoenzyme: antibacterial
IgA: immune protection
Nerve growth factor: ? protective
Epidermal growth factor: ? protective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Enzymes are always measured in..

A

Enzymatic activity, NOT mol NOT grams. They always have an optimal pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is salivary amylase activity maintained in the stomach?

A

by buffers and substrate protection. Inside the ‘sphere’ that is created (by the starch?), the pH is not so low as in the stomach. Therefore, the amylase is protected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What borders the oesophagus?

A

UES = Upper oesophageal sphincter
LES = Lower oesophageal sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does swallow-induced oesophageal peristalsis work?

A

> 

Ach (acetylcholine: neurotransmitter) stimulates contraction
NO (nitric oxide) + VIP (Vasoactive intestinal peptide) stimulate relaxation.

Secreted very close to each other.
Swallowing induces relaxation of LES and proximal stomach.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Mention the stomach parts in decending order of the bolus

A

Cardia: first part of stomach
Fundus: Upper part stomach
Body: big part
Antrum: lower part
Pylorus: final part
Pyloric sphincter: ending
p. 13

claus f bo als pen pie

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of LES + cardia?

A

Prevention of reflux
Entry of food
Regulation of belching (boeren)

17
Q

What is the function of antrum + pylorus?

A

Mixing
Grinding
Sieving
Regulation of emptying

18
Q

What happened during the cephalic phase is still happening during the gastric phase, however..

A

now the stomach is communicating back to the brain.
Mechanic receptors based on the stretching of the stomach > signal back to vagal system. “Digestion started, amplify the signal”.

19
Q

Receptive relaxation in the proximal (cardia, fundus, body) is dependent on..

A

The vagus nerve.

20
Q

What 2 things stimulate acid and pepsinogen secretion during the gastric phace?

A

Both vago-vagal reflex + endocrine release of gastrin
p.14

21
Q

Oligopeptides = ?

A

Sequence of 20-40 amino acids
Work as second messenger during the gastric phase

22
Q

Gastric pH= ? Of which enzyme is this the optimal pH?

A
  1. pH optimum for pepsin
23
Q

Why are acids already secreted in the cephalic phase?

A

Acids are already secreted in the cephalic phase, because it takes about 2 hr for the stomach to arrive at the optimum pepsinogen pH.

24
Q

How is pepsinogen activated? What kind of proteolytic activity does it have?

A

Pepsinogen -> cut into pepsin
Pepsin = endopeptidase, which cuts into the non-terimal amino acids. Specific for aromatic amino acids, leucine and methionine.
(exopeptidase cuts terminal amino acids)

25
Q

Vagal efferent outflow: Ach to target cells (also gastrin releasing cells). What do parietal/chief cells secrete? What do the endocrine gastric cells do?What do ECL cells do?

A

Parietal: H+, intrinsic factor (protein digestion, binding B12)
Chief cells: pepsinoge, gastric lipase (protein digestion, triglyceride digestion)
Endocrine: regulation of acid secretion
ECL: secrete histamine locally (lamina propria)

26
Q

Vit B12 is shielded through digestion. How does this work?

A
  • Salivary haptocorrin: acts as a shield around B12. Carries it until the stomach.
  • At the stomach: proteases secreted by the pancreas
  • Haptocorrin is a protein and will therefore be destroyed at the stomach. But, stomach also secretes IF (intrinsic factor).
  • Intrinsic factor: will shield B12 from this point on. > terminal ileum > reabsorbed to liver
    p.16
27
Q

See p.15 for figure of the cells of foldings of mucosa and lamina propria

A

ok

28
Q

What receptors does the parietal cells have? Or in other words, what can activate the parietal cells?

A

Gastrin (G-cells), histamine (enteroendocrine), acetylcholine (neurotr)

29
Q

During a meal, when you have a lot of secretory rate in your stomach, H+ goes up and ….. , to compensate

A

H+ goes up and sodium (Na+) goes down, to compensate.

30
Q

What happens as a feedback regulation when there is a lot of H+ secretion in the stomach when you eat a meal? Which agents are involved?

A

Feed-back via somatostatin

D cells: somatostatin producing cells. Located in antrum of stomach.
> When there is a lot of H+ secretion (pH going down), D cell notices this. Somatostatin is released, which inhibits the production of gastrin by the G cells.

31
Q

Stomach alters the physical and chemical characteristics of the meal. How much of protein and fat is digested in the stomach.?

A

10%

32
Q

What happens upon mixing and triglyceride digestion in the stomach concerning the release of a certain agent ?

A

Gastric mixing and triglyceride digestion liberate free fatty acids which are potent stimulants of CCK release.

33
Q

What does the hormone CCK do?

A

CCK :

Gall bladder contraction
Relax sphincter of Oddi
Decreased acid secretion
Decreased gastric emptying
Increased pancreatic enzyme

Released in the duodenum (?)

34
Q

A meal initiates three gastric motor responses during the gastric phase. What are these phases + what happens?

A
  1. Receptive relaxation
    Receptive relaxation of the fundus and body to accommodate the volume of the meal
  2. Mixing + grinding
    Antral peristalsis to grind the meal into small particles and mix with secretions
  3. Emptying
    Coordination of antro-pyloro-duodenal motor activity for regulation of gastric emptying. In addition, the reservoir function participates in emptying by regulation of fundus tone.
35
Q

What are requirements for the food before it can enter the duodenum?

A

Particle size: <2 mm (other wise sphincter wont open)
Osmolarity: mainly hypoerosmotic
Energy: ca. 8.5 kJ/min

36
Q

Slowest to fastest through the stomach?

A

Liquids quickest.

Or:
Hypertonic least, hypotonic (Water) medium, isotonic fastest

Nutritional physiology (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions