Brainscape's Knowledge GenomeTM

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


See full index

Physiology III > Lecture 29: Hindgut Fermentative Digestion > Flashcards

Lecture 29: Hindgut Fermentative Digestion Flashcards

1
Q

ruminants digest fiber prior to ___digestion

A

Glandular/autoenzymatic digestion

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

Almost all vertebrates facilitate bacterial digestion when

A

After auto-enzymatic digestion

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

What are the main productions of fiber digestion and autoenzymatic digestion

A

VFA’s, lactate, gas

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

Where does autoenzymatic digestion occur

A

Small intestine

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

What are some advantages of fiber digestion prior to autoenzymatic digestion (foregut fermenters)

A
  1. Use of bacterial biomass
  2. Detoxification of bacteria
  3. Upgrade of NPN
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a consequence of fiber digestion prior to autoenzymatic digestion/foregut fermenters

A

Downgrade high quality protein, loss of carb, malfermentation is possible

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

__ helps with detoxification in foregut fermentation

A

Bacteria

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

Bacterial digestion after autoenzymatic digestion allows more efficient use of ___

A

Substrates

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

__treatment helps breakdown and readily available carbohydrates are partly digested/absorbed

A

Acid

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

What is a disadvantage to hindgut fermentation

A

Loss of microbial protein because it does not pass stomach and SI

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

What are some nutritional advantages of hindgut fermentation

A
  1. Fermentation after enzymatic digestion and absorption
  2. Use of easily digestible substrates
  3. Diet shifts are less problematic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How can the loss of bacterial protein, bacterial products (B-vitamins) be avoid

A

Coprophagy- eating of cecotropes that are high in protein

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

Compare energy contribution of VFA in ruminants and monogastric species

A

Ruminants get energy from VFA through fermentation in the foregut whereas monogastric species get energy from VFA via fermentation in the hindgut

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

What are the two classifications of hindgut fermenters

A

Colon and cecum

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

What species are Cecal fermenters

A

Rabbits, guinea pigs, chinchillas and rats

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

Which species are colon fermenters

A

Horses, gorillas, elephants, rhinos

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

What species have barely any cecal capacity and an unsacculated colon

A

Dogs and cats

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

What species has a sacculated colon where a good deal of digestion takes place

A

Pigs

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

What role does the stomach play in preparing for hindgut fermentation

A

Prepares fibers for fermentation by first exposing to HCl

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

Where are easily digestible carbs, proteins and lipids handled in hindgut fermenters

A

SI

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

Where is cellulose and fiber handled in monogastric animals

A

LI

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

Why is water required for hindgut fermentation

A
  1. Provides flow of materials
  2. digestion/fermentation, and water reabsorption
  3. Electrolytes and buffers
  4. Optimal conditions for microbial growth/VFA production and absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where is the majority of water absorbed in large intestine

A

Cecum

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

What transporter does water utilize in the large intestine to be secreted into LI

A

Cystic fibrosis transmembrane receptor (CFTR) chloride channel

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

How does the CFTR channel work

A
  1. Secretes Cl- into lumen
  2. Na+ follows
  3. Water follows solutes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How is the CFTR channel activated

A

Food activates G protein receptors within LI where AC phosphorylates ATP to cAMP which activates pKa and opens CFTR channel

27
Q

What is the major anion in LI

A

VFA

28
Q

What mechanism is utilized to absorbed water in LI

A
  1. VFA utilizes HCO3-/Cl- exchanger and Na+/H+ exchanger
  2. Water will follow solutes
29
Q

What channel is used for water secretion in LI vs water absorption in LI

A

Secretion: CFRT
Absorption: VFA/bicarb exchanger

30
Q

Optimal conditions for microbial growth/VFA production and absorption require what 4 things

A
  1. Substrate
  2. Appropriate pH, osmolality, anaerobiosis
  3. Removal of waste
  4. Space and time (retention of fermenting material, mixing)
31
Q

What substrates supply LI for fermentation

A
  1. Carbohydrates in forms of fiber and non-structural material that don’t become available unless microbial activity breaks down cell wall
  2. Protein and NPN, urea recycled into colon and cecum
32
Q

What prevents limitation of microbial metabolism in hindgut fermentation

A

Recycling of urea into colon and cecum

33
Q

Microorganisms need___ for microbial protein synthesis

A

Nitrogen

34
Q

What maintains an optimal pH in LI

A

Secretion of bicarbonate and phosphate in ileum and removal of waste/absorption of VFA and lactate

35
Q

More grain leads to a build up of what

A

Proprionate—> gluconeogenesis—> lactic acid—> decrease pH, acidosis

36
Q

Where is VFA absorbed in hindgut fermenters

A

Cecum and colon

37
Q

___flow and specific ___ patterns of the LI facility the removal of waste

A

Water flow and specific motility patterns

38
Q

How is the dissociated/ionized form of VFA absorbed

A

Via VFA/bicarb exchanger

39
Q

How is the undissociated form of VFA absorbed

A

Lipophilic diffusion

40
Q

VFA and Na+ absorption in LI lead to osmotic absorption of ___

A

Water

41
Q

Why do we need two VFA absorption mechanisms for ionized and undissociated form

A

PH’s change

42
Q

What is the pK for VFA

A

4.8

43
Q

When is the ionized form of VFA favorably absorbed

A

PH>pK

44
Q

When is the pronated/undissociated form of VFA favorably absorbed

A

Ph=pk

45
Q

Fermenting material and residue are separated by particle and size in cecum and colon in a process called ___

A

Selective retention

46
Q

What are the three locations in which selective retention occurs

A
  1. Cecal constrictions
  2. Flexors pelvina
  3. Right dorsal colon
47
Q

How does cecal constriction work

A
  1. Contract at cecal body near apex
  2. Contractions move toward base creating pressure gradient
  3. Opening of cecocolic ostium (small so only small, fermented particles get through)
  4. Contraction of cranial compartment of cecal
48
Q

What does the flexura pelvina separate

A

Left ventral and dorsal colon

49
Q

How does the flexura pelvina selective retention work

A

Selective retention of coarse particles at the flexura pelvina and passage of fluid and small particles

50
Q

How does the right dorsal colon work in selective retention

A

Right dorsal colon has wide volume and subsequent transverse colon is narrow facilitating passage of fine particles and fluid and retaining large not fully fermented material

51
Q

In horses, what can disrupt the fermentation process in the right dorsal colon and explain how that works

A

Sand colic will increase diameter of R. Dorsal colon and pull it down this will not allow circular muscles and saccules to contract and move material into Transverse colon

This can result malfermentation, volvulus, or displacement

52
Q

Describe peristalsis in the ventral colon

A

Change from wide in the left ventral to narrow in left dorsal causing a squeezing only allowing small particles and liquid to pass

53
Q

Describe antiperstalsis in the left ventral colon

A

Reverse peristalsis that originates at mid colon, mixes ingesta and slows aboral digesta flow to allow fermentation to occur

54
Q

What structures in the ventral colon mix ingesta and thereby increase retention time for fermentation and VFA absorption

A

Hasutra and Tania coli

55
Q

Food particle __ determines retention time

A

Size

56
Q

Describe the results of grain over feeding in horses

A
  1. Capacity of stomach and SI are reached so ingesta is moved to LI
  2. Fermentation produces gas which interrupts motility and distends GI tract
57
Q

What is tympany

A

Distended GI tract

58
Q

Why does grain over feeding in horses cause discomfort/colic

A

Rapid production and accumulation of gas disrupts motility and distends GI tract

59
Q

During grain over feeding in horses some microorganisms produce __which increases the viscosity of the chyme and reduces peristalsis

A

Mucopolysaccharides

60
Q

How can tympany of LI cause gastrointestinal hyoperfusion and respiratory distress

A
  1. Blood vessels constricted causing decreased perfusion
  2. Respiratory distress due to gas compressing on diaphragm
61
Q

Grain over feeding promotes a low pH which results in the production of __acid and what is the result of that

A

Lactic acid as those microbes are favored by a decreased pH

62
Q

How does a lower pH impact mucosal barrier and endotoxin concentration

A

Damages mucosal barrier of cecum and colon causing ulceration and passage of endotoxins, enter circulation

63
Q

Circulation of endotoxins in horses can cause ___

A

Laminitis

Physiology III (34 decks)

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