Brainscape's Knowledge GenomeTM

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


See full index

Structure & Function 2 > GI tract physiology > Flashcards

GI tract physiology Flashcards

1
Q

What is prehension?

A

The act of moving food into the mouth
- Directly controlled by CNS

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

Which nerves are involved in prehension?

A
  • facial nerve
  • glossopharyngeal nerve
  • motor branch of trigeminal nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is mastication?

A

The first act of digestion
- Breaks food into particles; increase SA for digestion
- Moisten and lubricate food
- Involves stratified squamous epithelial cells & terminal branches of sensory neurons

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

Types of saliva

A
  • Mucous saliva; thicker, for binding food into a bolus
    ZYGOMATIC & SUBLINGUAL
  • Serous saliva; watery, contains amylase
    PAROTID
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What gland/s produce mucous saliva?

A

ZYGOMATIC & SUBLINGUAL

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

What gland/s produce serous saliva?

A

PAROTID

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Control of salivary glands

A
  • Mainly regulated by parasympathetic NS
  • Nerve fibres end on the acini
  • Stimulation causes increase saliva production
  • Salivary secretory cells; B-adrenergic receptors activated by sympathetic NS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the main components of saliva?

A
  • Mucins (glycoproteins)
  • Hydrogencarbonate ions (HCO3-)
  • Lysozyme & antibodies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Function of mucins in saliva

A

LUBRICATION; mix with water to form mucous

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

Function of HCO3- in saliva

A

pH REGULATION; neutralisation

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

Function of lysozyme & antibodies in saliva

A

ANTIBACTERIAL; keep number of bacteria in check

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

SPECIES SPECIALISATION; starch digestion

A

WHO? omnivores, single stomached herbivores & some birds
HOW? amylase

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

SPECIES SPECIALISATION; fat digestion

A

WHO? young calves
how? lingual lipase

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

SPECIES SPECIALISATION; theromoregulation

A

WHO? dogs and rodents
HOW? panting and spreading saliva

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

SPECIES SPECIALISATION; binding of tanins

A

WHO? leaf-eaters
HOW? binding proteins

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

SPECIES SPECIALISATION; providing urea

A

WHO? animals with forestomachs
HOW? urea diffuses from blood into saliva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

RUMINAT SPECIALISATIONS

A
  • Bicarbonate phosphate makes saliva alkaline
  • needed for neutralising fermentation products
  • cows can become easily dehydrated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the two phases of deglutition?

A

VOLUNTARY; chewed food is moulded into a bolus and moved to pharynx
INVOLUNTARY

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

The involuntary phase of deglutition

A

1) Breathing pauses
2) Soft palate elevates
3) Tongue pressed on hard palate
4) Glottis pulled under the epiglottis
5) When openings to pharynx are closed muscular contraction
passes over
6) upper oesophageal sphincter relaxes

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

Control of deglutition

A

Involuntary phase; by motor neurons in centres of the brainstem
- efferent nerve fibres travel in facial, hypoglossal and glossopharyngeal nerves

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

Differences in oesophageal muscle between species

A
  • Dogs, cattle & sheep; entire length is striated muscle
  • In horses, primates & cats; portion is smooth muscle
  • striated muscle; vagus nerve
  • smooth muscle; ENS
22
Q

Sphincters of oesophagus

A

Upper and lower; when deglutition NOT taking place body of oesophagus is relaxed but sphincters are closed

23
Q

3 main tasks of the stomach

A

1) Temporary food store
2) Some degradation of protein and starch
3) HCl kills bacteria in food

24
Q

Proximal stomach

A
  • mainly refers to fundus and cardia
  • stomach= empty; remains contracted (tonic contraction)
  • when animal eats; receptive relaxation which is regulated by vagal fibres
  • this aids food storage function
25
Q

Distal stomach

A
  • refers mainly to the pyloric area
  • more active digestion; stronger peristalsis
  • large part of wall contract forcing chyme through sphincter
  • large particles held back
26
Q

4 types of cells in the pits of the stomach wall

A
  • mucin-producing
  • parietal
  • chief
    -endocrine
27
Q

Gastric Secretions

A
  • produced in glands of fundus and corpus
  • glands in cardia region ONLY secrete mucus
  • gastric juice= HCl and pepsinogen
28
Q

Hydrochloric acid

A
  • Secreted from parietal cells
  • pepsinogen to pepsin
  • kills microorganisms
29
Q

Pepsinogen

A
  • synthesised by chief cells
  • inactive form of pepsin
  • pepsin degrades proteins into peptides
30
Q

Three substances involved in regulation of gastric sectretion

A
  • ACH
  • Gastrin
  • Histamine
31
Q

Regulation of gastric sectretion

A
  • production of HCl after a meal requires parietal cells to be stimulated by all 3 substances
  • gastrin; into blood to stimulate HCl secretion & pepsinogen
  • histamine; acts as a paracrine hormone; HCl secretion
32
Q

Inhibition of gastric secretion

A

-signals from duodenum if pH drops too low; blocks further HCl secretion

33
Q

Degradation through stomach

A

Proximal; recently swallowed food
- enzymes act; amylase
Distal; food is well mixed
-HCl
-Pepsin

34
Q

Factors affecting stomach emptying

A
  • Expansion of stomach wall
  • gastrin
  • Distention of duodenum; as D fills pyloric sphincter closes slowing chyme from S to I
    -High fat and protein conc.
  • Reduced pH
35
Q

The Abomasum

A
  • Epithelial glands produce pepsinogen and HCl
  • Young ruminants also produce rennin for milk digestion
    -NOT storage organ
  • low pH
36
Q

What are the two types of small intestine contraction?

A

Segmentation
Peristalsis

37
Q

Segmentation (SI)

A

Mixing movements/contractions
Non-propulsive

38
Q

Peristalsis (SI)

A

Propulsive movements, moves chyme through intestines

39
Q

Movements during the interdigestive period

A

Propulsive movements
Sweeps the intestine clean between meals
Between periods of peristaltic contraction
gets rid of bacteria

40
Q

Pacemaker cells in the small intestine

A

INTERSTITIAL CELLS OF CAJAL (ICC)
- Modified smooth muscle cells
- Slow waves constantly
- Muscle contractions only occur at same or lesser frequency than slow waves

41
Q

What structures in the small intestine increase surface area?

A

1) Folds in the inner surface of intestine (mucosa)
2) Mucosa covered in villi
3) Villi have microvilli

42
Q

Enterocyte structure

A
  • Apical membrane; contact with intestinal lumen
  • Tight junctions (loose); connect adjacent enterocytes
43
Q

2 Mechanisms of absorption from SI

A

Transcellular; organic nutrients transported from intestine to interstitial fluid across enterocytes
Paracellular; inorganic ions & water can diffuse through tight junctions

44
Q

4 types of large intestine contraction

A
  • Segmentation
  • Peristalsis
  • Anti-peristalsis
  • Mass Movements
45
Q

Segmentation (LI)

A
  • Haustra formed
  • Movement of content back and forth
46
Q

Antiperistalsis

A

Increase transit time; delaying transit of chyme filling the caecum

47
Q

Pelvic flexure

A
  • narrow portion between ventral and dorsal colon in horses
  • Similar function to a sphincter
  • large particles cannot pass through
48
Q

Mass Movements

A

-Produce faeces
- Then peristaltic contractions of the rectum follow to defecate.

49
Q

Diarrhoea

A

An increase in defecation frequency or fecal volume
- results in disturbed balance between influx and efflux

50
Q

Malabsorptive diarrhoea

A

Occurs when absorption is inadequate to recover a sufficient amount of secreted water
- can be caused by infection
- causes loss of epithelium and aquaporins

51
Q

Hypersecretory diarrhoea

A
  • occurs when rate of intestinal secretion increases and overwhelms absorptive capacity
52
Q

How does E. coli and Salmonella cause diarrhoea?

A

Causes Hypersecretory diarrhoea
- produces enterotoxins
- bind to the epithelium and causes cAMP activity causing the opening of chloride channels
- causes water and electrolytes to be secreted from crypt epithelium

Structure & Function 2 (16 decks)

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