Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

RUSVM Physiology II > GI 4 > Flashcards

GI 4 Flashcards

(64 cards)

Start Studying
1
Q

What type of digestion occurs in the forestomach of ruminants or in the cecum/colon of horses

A

Fermentative digestion

Digestive enzymes of microbial origin

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

The forestomach of the ruminant is lined with _____________________ epithelium

A

Stratified squamous epithelium

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

What is the true stomach in ruminants?

A

Abomasum

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

What is the largest compartment of the newborn ruminant stomach?

A

Abomasum

Enlargement of the forestomach occurs after birth

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

What type of protozoa in the forestomach are _________ and belong to genus _______ and _______________

A

Ciliated; isotricha or entodinium

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

Describe the ruminal environment

A

Substrate availability : food intake regulates by volume, structure, energy, palatability

Temperature: 0.5 to 1 C above body temp

Fluid: drink water and saliva

pH: 5.5–7

Osmolarity: 260bis>400mOsm/L

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

What is an example of symbiosis of the ruminant stomach?

A

Waste products of one species serve as a substrate for another

Eg
R.albus digests cellulose –> hexose, but not protein
B.rumincola detests protein –>fatty acid and ammonia

R.albus requires ammonia and fatty acid for growth
R.rumincola requires hexose for growth

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

What are the layers of the ruminal contents?

A

Gas
Fiber mat
Intermediate zone
Liquid zone

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

Rumen microbes intake carbohydrates, protein,and lipids to form ?

A

Volatile fatty acid

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

What enzyme hydrolyzes cellulose, hemicellulose, and pectin?

A

Cellulase (in the rumen)

Polysaccharide to monosaccharide

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

What must occur in the fore stomach for glucose, monosaccharides, and short chain polysaccharides to be absorbed by the animal

A

Microbe uptake
Glucose- glycolytic pathway -> 2pyruvate, 2NADH, and 2ATP

Anaerobic fermentation digestion to produce volatile fatty acids AKA short chain fatty acid (SCFA)

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

What are the primary volatile fatty acids

A 
Acetic acid (acetate)
Propionic acid (propionate) 
Butyric acid (butyrate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What component of plants, that increase with age and ambient temperature of the plant is not digestible?

A

Lignin

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

________ on the surface of microbes generate peptides

A

Protease

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

What is the fate of short chain peptides in the microbial cell?

A

Hydrolyzed to amino acids

  • > synthesis of microbes protein
  • > metabolized to VFA and ammonia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Microbes used _______ and __________ to synthesize amino acids

A

Ammonia (NH3) and volatile fatty acids (VFA)

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

What is required for an amino acid to enter the VFA pathway?

A

Deamination

amino acid –> NH3 + carbon skeleton

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

Most amino acids following deamination can enter directly into the VFA pathway except for?

A

Branch-chain aa (BCAA)

Eg valine
Leucine
Isoleucine

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

Most dietary protein undergoes fermentation in the microbes within the rumen. How does the animal meet its protein needs?

A

Microbial proteins

Microbes are washed out of the rumen with rumen fluids to the abomasum and small intestine -> digestion of microbes

Other sources
Ammonia, nitrates, and urea synthesized to protein within rumen

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

Urea can be recycled to the rumen to produce proteins for the host, what are the two sources of urea?

A

Deamination of endogenous amino acids -> ammonia
Nitrogen absorbed as ammonia from rumen

Liver turns ammonia back to urea which is returned back to the rumen

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

What enzymes do microorganisms produce for lipid digestion

A

Lipase and phospholipids

Usually rare in plants, but fats are added to diets to increase energy density

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

What major type of lipid is found in cereal grains, oilseeds, animal fats, and byproduct feeds?

A

Triglycerides

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

What major lipid if found in forages?

A

Glycolipids

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

What minor components of most feeds forms cell membranes of animal cells and the surface of milk fat globules

A

Phospholipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What minor component of diary feeds is a major component of fat supplements
Free fatty acids
26
How are fats hydrolyzed in the ruminant?
Microbial lipase Anaerovibrio lipolytica -> triglycerides Buyrivibrio fibrisovlens -> phospholipid and glycolpids
27
Microbial lipase hydrolyze fats to ?
Glycerol, sugars, and free fatty acids
28
Glycerol and sugars are formed into ______in the rumen microbes
Volatile fatty acids
29
Fatty acids released from fatty acids undergo ____________
Hydrogenation Unsaturated fatty acid -> saturated fatty acid Absorbed in the small intestine
30
What is the ratio of VFA in ruminants
Acetic/propionic/butyric acid High forage (fiber) diet-> 70:20:10 High grain (starch) diets -> 60:30:10 The ratio of acetate is lower in the starch diet but the total about produced is greater than the fiber diet
31
Microbes can synthesize what vitamins
C, K , B
32
A ____________ deficiency can be observed when a ruminants diet is suddenly changed from roughage to concentrate
B1 (thyamin)
33
A ________ deficiency can be observed in cobalt poor solids or with diets too high in grain
B12 (cobalamin)
34
What are the two main mechanisms that VFA are absorbed in the rumen
Ionized- require carrier (HCO3-/Ac-antiport) Non-ionized - diffuse through apical membrane
35
What is rumen acidosis ?
Fast-fermentable carbohydrates (starch rich) can lead to increased VFA production --> acids decrease the pH of rumen VFA have pka of 4.8 => more acid will be in HAc form than Ac- HAc can diffuse direct through membrane Less Ac- antiport with HCO3- (less HCO3- to rumen => pH increases) Acidic pH -> proliferation of lactate-producing bacteria --> lactic acid -> more acidic
36
How is sodium absorbed in the rumen?
Na+ channel- Apical (electrochemical gradient) Na/N exchanger -apical Na/K ATPase- basolaterally
37
How is chloride reabsorbed into the rumen?
Cl-/HCO3- exchanger -apical Basolateral channel
38
How is potassium absorbed in the rumen?
Apical and basolateral channels - high luminal K+ concentration (transepithelial potential difference)
39
How is magnesium absorbed in the rumen?
Mg2+ channel Affected by K+ concentrations
40
How is calcium reabsorbed int he rumen?
Not well understood Apical- probably Ca/H exchanger Basolateral - Na/Ca exchanger and Ca ATPase
41
What are the functions of the omasum?
Concentrate ingesta (absorb water) VFA (SCFA) absorption - diffusion Na and Cl absorption (cotransporter) HCO3- reabsorbed (antiport with Cl-)
42
What are the two mobility patters on the rumen?
Mixing (primary) Erutation (secondary)
43
What are the steps of the mixing/primary contractions of the rumen?
Bolus enter rumen to cardia Biphasic contraction of rumen - weak followed by forceful to push larger particles to dorsal sac Caudal-moving contraction of dorsal sac pushes ingesta farther back Cainial-moving contraction of dorsal sac- > mix ingesta and start bacteria fermentation Smaller particles decant to ventral sac separates big and small material Ventral sac contraction- smaller particles to over crainial pillar to the crainial sac Cranial sac contracts -further separates to small and large particles Recticulum contract, recticulum-omasal orfice relax and small particle go omasum
44
What is the main function of primary contractions of the rumen?
Reduce particle size
45
What the the function of secondary contractions of the rumen?
Force gas toward the cranial portion of rumen Occurs at end of primary contraction cycle
46
What are the secondary contractions of the rumen?
Cranial-moving contraction staring in cardio-dorsal blind sac Contraction moves toward cardia forcing gas to esophagus
47
How many recticular-rumen contractions occur per minute
1-3 Rate and strength depend on structure of diet
48
What are the main gases produced during rumination?
CO2 | Methane
49
the ________________center is located in the medulla and receives afferent fibers from mechanoreceptor in the dorsal sac where gas accumulates
Eructation
50
What can occur in cattle when the eructation mechanism fails ?
Tympanism or bloating
51
What is legume bloat?
Cattle eat fast growing clover/alfalfa Gas trapped in plant material and doesnt rise to dorsal sac Mechanoreceptor do not detect gas Eructation mechanism fails
52
When cattle do not have enough oxaloacetate or an excessive amount of acetylCoA, often seen in high-producing dairy cattle, what condition develops?
Ruminant ketosis Acetyl CoA -> acetoacetyl CoA -> ketone bodies (acetoacetate, betahydroxybutyrate, and acetone)
53
What controls reticulorumen motility
ENS and vagus nerve Stretch receptors/chemoreceptor-> afferent to brainstem (dorsal vagus nucelus)->vagus nerve
54
What invagination of the wall of the reticulum spans from the cardia to the recticulo-omasal orfice; it diverts milk away from developing rumen, directly into abomasum
Recticular groove (esophageal groove)
55
What closes the reticular groove, so milk bypasss the rumen and directly enters the abomasum
Reflex Anticipate suckling and suckling -> CNS -> brainstem -> vagus nerve -> groove contracts forming a tube
56
Horses and rabbits are ___________ fermenters
Hindgut
57
What are the substrates required for hindgut fermentation?
Carbohydrates and proteins
58
What is the product of hindgut fermentation
Volatile fatty acids
59
What must be controlled to maintain fermentation in the hindgut
``` Substrate supply Control of pH Osmolarity Anaerobiosis Retain fermentation material Remove wastes ```
60
What is the predominant motility pattern of the cecum? How does this differ from the ventral colon?
Cecum: Low-amplitude contractions move ingesta from haustra to haustra (mixing) Ventral colon: haustra segmentation and retropulsive peristalsis (mixing) and propulsive peristalsis (movement)
61
Carbohydrates digestion in ruminants takes place mostly in the?
Forestomach Almost no digestible carbohydrate enters intestine
62
All the glucose available to ruminants is formed by ________________
Gluconeogenesis
63
What volatile fatty acid is the most important precursor for gluconeogenesis of ruminants
Propionate | Will enter Krebs cycle as succinate
64
Proprionate is absorbed from the portal blood supply by the _________
Liver Never enters systemic circulation

RUSVM Physiology II (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions