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Physiology Exam 3 > Lecture 54- Ruminant Digestive Physiology I > Flashcards

Lecture 54- Ruminant Digestive Physiology I Flashcards

1
Q

What is the gastric stomach?

A

Abomasum

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2
Q

What makes up the ruminant forestomachs? What type of cells?

A

Rumen, reticulum, omasum

Stratified squamous epithelium
No glands
Pillars and papillae

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3
Q

Describe the evolution of ruminants. What is the digestive strategy?

A

Ingest enormous quantities of forage in short time minimizing exposure in the open

Spend maximal time ruminating in the protection of trees and rocks

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4
Q

What is the ruminant GIT compartmentalized in:

A

Rumen, reticulum, omasum, abomasum

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5
Q

How is pre-gastric fermentation accomplished?

A

By microbes

Allows animals to more completely utilize products of fermentation

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6
Q

Pseudoruminats have no ______

A

Omasum

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7
Q

Where is the site of fermentation for ruminants?

A

Rumen

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8
Q

Where is the site of fermentation for non ruminants?

A

Cecum and large intestine

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9
Q

What are examples of ruminant species?

A

Cattle
Bison
Sheep
Antelope
Goats
Deer
Elk

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10
Q

How is food physically broken down?

A

*prehension-lips, tongues
*mastication during eating + rumination.
Rumination = regurgitation + remastication
*microbial fermentation (accomplished by bacteria, fungi, yeast, Protozoa)

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11
Q

What are the three major salivary glands?

A

Parotoid
Sublingual
Mandibular

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12
Q

What is the composition and function of saliva?

A

Composition: bicarbonate, urea, K, inorganic phosphate, Cl

**Buffering is the number 1 function, adding moisture and lipase

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13
Q

Which environmental conditions are needed to support fermentation?

A

Appropriate substrate
Temperature around 37
Osmolarity near 300 mOsm
Anaerobic conditions
Frequent mixing of ingesta
Particle size reduction
Indigestible material removal
Synchronized movement of fermented content to intestine
VFA must be buffered to maintain neutral pH

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14
Q

Where does 60-75% of digestion occur? Also the primary site of fermentation?

A

Rumen

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15
Q

What do amylolytic bacterial species consist of?

A

Starch and sugars

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16
Q

What do cellulolytic bacterial species consist of?

A

Cellulose, hemicellulose

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17
Q

What are the end products of fermentation?

A

Acetate, propionate, butyrate

*very important to remember: more acetate in high fiber and more propionate on high-grain**

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18
Q

What do papillae and extensive capillaries do in the rumen?

A

Increase surface area, absorb

*larger on high grain diets

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19
Q

What is the function of the reticulum?

A

Form bolus for regurgitation
Move particles to omasum
Move particles to rumen

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20
Q

How do materials from rumen pass into omasum?

A

Via the reticulo-omasum orfice

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21
Q

What does the omasum regulate?

A

Passage of digesta into lower tract

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22
Q

What is absorbed in the omasum?

A

Water and VFA

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23
Q

What do the gastric glands in the abomasum secrete?

A

HCl

Acidity kills microbes washing in from rumen—starts digestion
Major source of protein for animal essential AA -> digested and absorbed in SI

24
Q

What does the abomasum secrete? And why?

A

Pepsinogen

Hydrolysis microbial and dietary protein

25
Q

How many times do abomasal contractions occur?

A

2-3 per minute

Mixing, material exits to SI, and drive gas back into the rumen

26
Q

What do forages contain?

A

Cellulose, hemicellulose, sugars, starch, protein, lignin

27
Q

What do concentrates (grain) contain?

A

Starch, protein, sugar

28
Q

What are the layers of the rumen?

A

-small high density on bottom
-liquid
-fibermat (larger, low density) -> scratch fiber
-then gas layer

29
Q

What are examples of micro flora?

A

Bacteria, Protozoa, fungi

30
Q

Primarily feeding the ______—then the cow.

A

Flora

31
Q

What is the definition of fermentation?

A

Microorganism-mediated transformation from one nutrient compound to another

32
Q

Which products undergo fermentation in the rumen?

A

Monosaccharide
Disaccharide
Starch
Cellulose
Other Sugars

33
Q

Which carbohydrates are fermented in the rumen to VFA? and at what percent?

A

Acetate (60%)
Propionate (30%)
Butyrate (10%)

*acetate is higher with forage diets
*butyrate is higher with grain diets

34
Q

What does gluconeogenesis use to make glucose?

A

Propionate

35
Q

What does fat synthesis utilize?

A

Acetate

36
Q

What do ruminants use for energy?

A

VFA

37
Q

What is the blood glucose in most non-ruminants? Is this lower or higher than normal?

A

60 mg/dl

38
Q

What is the pathway for sugars, starch, cellulose, and lignin to turn into VFA?

A

Sugar -> VFA
Starch -> Glucose -> VFA
Cellulose -> Glucose -> VFA
Lignin -> Undigested

39
Q

What proteins fermented to?

A

Peptides
Amino acids
Ammonia
Branched-chain VFA

40
Q

What do microbes use in synthesizing cell walls and the cytoplasmic reticulum?

A

Protein components and metabolites

41
Q

Where are dead microflora digested?

A

Small intestine

42
Q

What provides the highest quality protein possible?

A

Microbes

43
Q

(TRUE/FALSE) If you feed low quality proteins or metabolites (urea) the cow absorbs lowest quality amino acids from small intestine.

A

FALSE

The cow absorbs the HIGHEST quality amino acids

44
Q

What is ammonia produced in rumen from?

A

Protein fermation

45
Q

What happens to the ammonia produced in the rumen?

A

Immediately utilized by microbes

Absorbed and converted to urea by the liver

46
Q

What are the three fates of urea?

A
  1. Excreted by kidney
  2. Recycled to saliva
  3. Recycled to rumen
47
Q

How do rumen primary contractions move?

A

Cranial to caudal

48
Q

How do rumen secondary contractions move?

A

Caudal to cranial primarily to erucatate gas

49
Q

What are reticular contractions associated with ?

A

Cud chewing

50
Q

What are the four steps of rumination?

A

Regurgitation, reinsalviation, remastication, reswallowing

51
Q

What is regurgitation initiated by?

A

Initiated by a reticular contraction AND relaxation of distal esophageal sphincter

52
Q

When does rumination occur?

A

30-90 minutes after eating
Occurs when animal is resting
Ruminate up to 10 hours a day

53
Q

What is the importance of rumination?

A

Rumination keeps food intake constant
Removes air and gas pockets from forage -> allows particles to sink

54
Q

What is rumination is initiated by?

A

“Extra” contraction of reticulum that pushes ingesta into area of cardia

55
Q

Which esophageal sphincter opens during rumination?

A

Distal esophageal sphincter

56
Q

What is the process of rumination?

A
  1. Initiated by extra contraction of reticulum that pushes ingesta into area of cardia
  2. Distal esophageal sphincter open
  3. Inspirator excursion with glottis closed causing negative pressure in in trat Horacio esophagus
  4. Bolus of ingesta moves into esophagus

Physiology Exam 3 (17 decks)

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