Brainscape's Knowledge GenomeTM

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


See full index

Physiology 2001 > Gastrointestinal Physiology > Flashcards

Gastrointestinal Physiology Flashcards

1
Q

What are the functions of gut nerves and hormones?

A
  • Coordinate motility to deliver food to the appropriate area at a rate readily handled by the small intestine
  • Stimulate secretion when food is in the right place
  • Turn off secretion when food is absent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Digestion is controlled extrinsicly by the …………..

A

Autonomic nervous system via the Parasympathetics and Sympathetics

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

Digestion is controlled intrinsicly by the ……………

A

Enteric Nervous system via the Myenteric plexus and Submucous plexus

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

What are the phases of digestion?

A

Interdigestive
Cephalic
Gastric
Intestinal

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

What are the functions of Gastrointestinal system?

A

Secretion
Mixing and metering of food
Absorption
Excretion

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

Describe digestion in the mouth:

A
  • Teeth mechanically digest food
  • Salivary glands secrete mucous, lysozymes and salivary amylase
  • Amylase begins starch digestion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Salivary glands are activated by the __________ and chewing

A

Parasympathetics and Chewing

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

Sympathetic stimulation of the salivary glands _______________________________

A

Changes the composition of saliva

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

Ring-like __________ contractions move the bolus of food down the oesophagus

A

Peristaltic

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

The stomach is a _____________ of the alimentary canal and it is involved in ________, _______ and ________ of food

A

Muscular dilation

Digestion, Metering and Mixing

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

What does the stomach produce?

A

HCl
Pepsinogen
Mucous
Intrinsic Factor

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

Irrittations of the stomach can lead to ________, an increase in ________ pressure ejects food out of the stomach

A

Retropulsion aka vomiting

Abdominal

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

In the body region of the stomach there are glands that contain ________, _________, ______________ and ____________.

A

Chief Cells
Parietal Cells
Enterochromaffin-like cells ECL cells
Mucous Surface Cells

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

What do Chief Cells do?

A
  • Release pepsinogen, a proteolytic pro-enzyme
  • Pepsinogen is converted to pepsin when exposed to acid
  • pepsin begins protein digestion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do Parietal Cells do?

A
  • Produce HCl
  • Acid is produced by a proton pump (K+ is pumped into the cell, H+ and Cl- are pumped out into the stomach)
  • Secrete intrinsic factor which is needed for vitamin B12 absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What do Mucous Surface cells do?

A
  • Produce mucous rich in HCO3 to protect the stomach wall from damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do Enterochromaffin-like Cells do?

A

Produce histamine to stimulate acid production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do G cells do?

A

Producen gastrin to stimulare acid production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

During the cephalic stage of digestion ____________ stimulate Gastric secretion.

A

Parasympathetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Explain the factors that affect acid secretion during the cephalic phase:

A
  1. Sight/Smell/Taste stimulates the parasympathetics
  2. G cells are activated by Ach released from parasympathetic nerves
  3. ECL cells release histamine in response to Ach from parasympathetics and Gastrin
  4. Gastrin, Ach and Histamine (most important factor) bind to the parietal cell and cause acid secretion

This accounts for 30% of acid secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The stomach is usually collapsed during the __________, but when food enters the stomach it expands. This prevents ____________

A

Interdigestive phase

Pressure build up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Explain the factors that affect acid secretion during the gastric phase:

A
  1. Stretch receptors detect stomach distension and activate the parasympathetics
  2. G cells are activated by AAs/peptides detected by the villi on G-cells and Ach released from parasympathetic nerves
  3. ECL cells release histamine in response to Ach from parasympathetics and Gastrin
  4. Gastrin, Ach and Histamine (most important factor) bind to the parietal cell and cause acid secretion

This accounts for 60% of acid secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Coffee, Beer and Wine can ________ Gastrin secretion

A

Increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

H2 receptors in the parietal cells respond to _________

A

Histamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Muscarinic receptors in the parietal cells respond to _________

A

Ach from parasympathetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Gastrin receptors in the parietal cells respond to _________

A

Gastrin

DUH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How are chief cells activated to secrete pepsinogen?

A

In the same was as parietal cells are activated to secrete HCl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the function of an Antral Somatostatin cell?

A
  • Chemoreceptors on the villi on this cell detect changes in pH
  • When pH decreases it releases a localised dose of somatostatin to the G-cell and decrease Gastrin secretion
  • Decreased Gastrin = decreased acid production
29
Q

The gel like structure of the __________ layer __________ the rate of H+ diffusion

A

Mucous layer

Decreases

30
Q

To eject food, the _____ of the stomach pinches off and _________________ forces the chyme through the _______ sphincter

A

Antrum
A wave of peristaltic contraction
Pyloric Sphincter

31
Q

When the first dose of chyme enters the duodenum we get the final _________________, However as more chyme leaves the stomach this quickly become _________

A

10% of acid secretion

Inhibitory

32
Q

What are the sections of the small intestines?

A

Duodenum
Jejunum
Ileum

33
Q

Explain how gastric emptying is controlled:

A 
INTRINSICLY =  Plexus in the duodenal wall and antrum detect distension of the duodenum and this slows emptying
EXSTRINCLY = Vago-vagal nerve reflexes are also involved
34
Q

________ stimulate secretion from the pancreas

A

Hormones

35
Q

________ stimulate the contraction of the gall bladder

A

Hormones

36
Q

The ____________ prevents secretions from the _______ and _______ entering the duodenum when food is absent

A

Sphincter of Oddi
Pancreas
Bile Salts

37
Q

Acinar cells are _________ in structure that secrete into a _______

A

Grape-like

Lumen

38
Q

What do Acinar cells produce?

A

Proteases
Lipases
Amylases
Nucleic Acid enzymes

39
Q

Intercalated duct cells are found in the ducts leading from the ________ and secrete _________

A

Acinar Cells

HCO3-

40
Q

What factors control exocrine pancrease secretion?

A
  • Vagus (Parasympathetic) nerve controls enzyme and HCO3- secretion
  • Hormone Cholecystokinin (CCK) controls enzyme secretion
  • Hormone Secretin controls HCO3- secretion
41
Q

CCK RF and trypsin are ___________________ into the duodenal lumen. Trypsin _________ CCK RF and therefore CCK is _____________

A

Continuously released
Breaks down
Not release

42
Q

Trypsin has a greater affinity for ___________ rather than _________. Therefore the concentration of _____ increases and causes release of enzymes

A

Dietary proteins
CCK RF
CCK

43
Q

Explain how CCK stimulates Enzyme release:

A
  1. CCK activates the vagal afferent which causes an increase in parasympathetic stimulation
  2. Parasympathetics stimulate the acinar cells
44
Q

If you cut the ________ or apply _______ you get inhibition of enzyme secretion

A

Vagal efferent

Atropine

45
Q

Besides stimulating enzyme secretion, what are the other functions of CCK?

A
  • Stimulates gall bladder contraction
  • Induces relaxation of the Sphincter of Oddi
  • Inhibits gastric secretion and emptying
46
Q

Explain how Secretin causes secretion of the HCO3-:

A
  1. Secretin is released from eneterocytes in response to acid
  2. Secretin stimulates the vagal afferent like CCK which increases parasympathetic stimulation to the intercalated duct cells
  3. Directly stimulates secretion via the blood as, unlike acinar cells, intercalated duct cells have receptors for Secretin
47
Q

Bile is reabsroped in the ______ via the _______________. ___% of bile salts are reabsorped

A

Ileum
Portal Circulation
95%

48
Q

Hepatocytes absorb bile salts from the ________ and then transports them towards the _________

A

Capillaries

Bile Duct

49
Q

Bile salts are ______________ with a hydrophillic and hydrophobic region

A

Planar Amphipaths

50
Q

Bile salts _______ fats globules via _______. This increases the surface area for digestion by _______

A

Emulsify
Agitation
Lipases

51
Q

Lipases breaks down triglycerides into ___________ and __________.

A

Monoglycerides

Free Fatty Acids

52
Q

When micelles aproach the intestinal wall they ________. ____________ and __________ are then able to diffuse into the cells

A

Break apart
Monoglycerides
Free Fatty Acids

53
Q

Most absorption occurs in the ________

A

Jejunum

54
Q

________ and ______ are absorbed in the ______

A

Vitamin B12 and bile salts

Ileum

55
Q

On the microvill of ________ there are _________ and lots of membrane bound _________

A

Enterocytes
Glycocalyces
Enzymes

56
Q

Inside the enterocyte, _________ are reformed and coated with a _______ protein layer. They are then exocytosed into the interstitial fluid where they can be absorbed into ___________

A

Triacylglycerides
Chylomicron
Lymphatic vessels

57
Q

________ cuts at the α-1,4 linkages in starch and we get __________, __________ and ________.

A

α amylase
Maltose
Maltotriose
α-limit dextrans

58
Q

Membrane bound enzymes break down complex sugars into ________, _________ and ________.

A

Glucose
Fructose
Galactose

59
Q

_____ and _____ transport all simple sugars into the enterocyte. _____ transports fructose and _____ transports _______ and ______

A

GLUT5 and SGLT1
GLUT 5 transports fructose
SGLT1 transports glucose and galactose

60
Q

Isomaltase breaks down ________ into _______ and _______

A

α-limit dextrans
Maltotriose
Maltose

61
Q

Glycoamylase breaks down ______ and _________ into __________________.

A

Maltose
Maltotriose
Single glucose molecules

62
Q

Lactase breaks down _______ into ________ and _______

A

Lactose
Glucose
Galactose

63
Q

Sucrase breaks down _______ into ________ and _______

A

Sucrose
Glucose
Fructose

64
Q

______ transports Glucose and Fructose into the interstitial fluid where it can be ____________________

A

GLUT 2

Absorbed into the blood

65
Q

Enterocytes can absorbed peptides that are less than ___ AAs in length.

A

4

66
Q

Peptides that are absorbed into the enterocytes are broken down further by _________ into _________

A

Peptidases

Single amino acids

67
Q

Water in the intestines is absorbed in the same way as ____________. We absorbed about __% of water.

A

In the kidney

95%

68
Q

What are the main functions of the large intestines?

A
  • Digestion of dietary fibre by bacteria
  • Dessication, removal of more water
  • Formation and storage of faeces
69
Q

Faeces is made of:

A
  • Dead Cells
  • Indigestible material
  • Bacteria
  • Water

Physiology 2001 (7 decks)

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