Exam 3 – Dr. Brashier Equine GI Flashcards Preview

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Flashcards in Exam 3 – Dr. Brashier Equine GI Deck (100)
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1
Q

Do herbivores have grinding or shearing teeth?

A

Grinding

2
Q

What happens when herbivores grind high silica content feed?

A

Wears away teeth

3
Q

What are hypsodont teeth?

A

Teeth which have a limited growth period, but prolonged eruption

4
Q

What happens to odontoblasts in horses?

A

They remain active throughout the life of the tooth synthesizing regular secondary dentin and also irregular secondary dentin on the periphery of the pulp horn throughout most of the life of the tooth

5
Q

What does the synthesizing of secondary dentin do?

A

Gradually reduces the size of the pulp cavity and thus of the pulp and eventually fully occludes the pulp horn

6
Q

What are the 3 main types of dentin?

A

Primary dentin
Secondary dentin
Tertiary dentin

7
Q

What is primary dentin?

A

Laid down as the tooth forms before it erupts and is in wear

8
Q

What is secondary dentin?

A

Continues to form as the occlusal surfaces worn away and the pulp cavity retracts so that the secondary dentin seals off the pulp cavity so that it is not exposed as the tooth wears away

9
Q

When is tertiary dentin formed?

A

In response to local insults

10
Q

Where do odontoblasts reside?

A

At the periphery of the pulp cavity, but their odontoblast processes extend through the dental tubules

11
Q

What is the bulk of the tooth composed of?

A

Dentin

12
Q

What is dentin?

A

A cream colored, calcified tissue composed of approximately 70% minerals and 30% organic components

13
Q

What happens to the pulp cavity?

A

It is constantly retracting

14
Q

What is secondary dentin doing?

A

Constantly being laid down to seal pulp cavity

15
Q

When do the permanent premolars erupt?

A

06s: 2.5 years
07s: 3 years
08s: 4 years

16
Q

When do the molars erupt?

A

1, 2, and 3.5 years, respectively

17
Q

When do the incisors erupt?

A

2.5, 3.5, and 4.5 years

18
Q

What should the teeth be like by 5 years?

A

All caps should be gone and all teeth fully in wear against the opposite member

19
Q

How much do teeth wear away?

A

2-3 mm/yr

20
Q

What happens at 7 years of age with teeth?

A

The root development slows and overall length of all teeth begins to become shorter

21
Q

When does tooth development stop?

A

12-15 years

22
Q

What is anisognathic?

A

Upper arcade 25-30% wider than lower

23
Q

What does anisognathic teeth lead to?

A

Naturally leads to sloped occlusal surface, which increases feed efficiency

24
Q

What happens since incisors meet?

A

Cheek teeth do not meet

25
Q

What are points?

A

Where teeth do not meet

26
Q

What is the consequence of hypsodont teeth?

A

Any malocclusion lead to dental overgrowth, which can lead to poor feed utilization and loss of body condition

27
Q

What are ulcers created by points prevented by?

A

Rasping sharp edges

28
Q

What is the most common malocclusion?

A

Points

29
Q

What is the second most common malocclusion?

A

Hooks
Having the upper arcade set relative to the lower arcade, which results in the rostral aspect of the upper first cheek tooth having nothing to wear against and subsequently getting overly long

30
Q

What is the rostral 2/3 of the esophagus made of?

A

Striated muscle

31
Q

What is the causal 1/3 of the esophagus made of?

A

Smooth muscle

32
Q

What is the lower esophageal sphincter of the esophagus like?

A

Very well developed

33
Q

Horses do not like vomiting. What will they do before regurgitating or vomiting?

A

They will rupture their stomach

34
Q

What can be lifesaving with colic?

A

Passing a stomach tube

35
Q

Which GI tract tends to be more complex, herbivores or carnivores?

A

Herbivores

36
Q

What is the nervous control of the GI tract through?

A

Enteric nervous system

37
Q

What is the volume of the stomach?

A

8-15 L

38
Q

What percentage of the GI tract is the stomach?

A

8%

39
Q

What is the length of the small intestine?

A

70 ft.

40
Q

What is the volume of the small intestine?

A

40-60 L

41
Q

What percentage of the GI tract is the small intestine?

A

30%

42
Q

What is the length of the cecum?

A

4 ft.

43
Q

What is the volume of the cecum?

A

28-36 L

44
Q

What percentage of the GI tract is the cecum?

A

15%

45
Q

What is the length of the large colon?

A

10-12 ft

46
Q

What is the volume of the large colon?

A

80-90 L

47
Q

What percentage of the GI tract is the large colon?

A

38%

48
Q

What is the length of the small colon?

A

10-12 ft

49
Q

What is the volume of the small colon?

A

16 L

50
Q

What percentage of the GI tract is the small colon?

A

9%

51
Q

Look at GI tract

A

Look at GI tract

52
Q

What kind of non-ruminant herbivores are horses?

A

Hind-gut fermenter

53
Q

What is the stomach of a horse like?

A

Simple stomach that digests simple CHO sources, but can utilize fibrous sources

54
Q

Where does all true enzymatic digestion occur in the horse?

A

In the fore gut ahead of the cecum

55
Q

What does the enzymatic digestion in the fore gut account for?

A

52-58% of the crude protein digestion, all protein absorption, all long chain lipid absorption, and virtually all soluble CHO digestion and absorption

56
Q

Where does bacterial or microbial digestion of fiber CHO occur?

A

In the cecum and colon where large quantities of VFAs are produced through fermentation and absorbed

57
Q

What happens since there is no enzymatic digestion in the large intestine?

A

All other products of microbial proliferation are lost to the horse

58
Q

What are the 4 major regions of the stomach?

A

Stratified squamous epithelium, cardiac, fundic, and pyloric

59
Q

What is the stratified squamous epithelium of the stomach like?

A

Does not contain any glands or mucus producing cell and ends abruptly at the margo plicatus

60
Q

What does the cardiac mucosa contain?

A

Mainly mucus and bicarbonate producing glands

61
Q

What are the glands in the fundic region responsible for?

A

Produce some mucus, but primarily responsible for acid and protease production

62
Q

What do the pyloric glands do?

A

Mucus production (rich in mucus producing glands)
Some bicarbonate production
Some protease production

63
Q

What breaks down food in the stomach?

A

Acids and the enzyme pepsin

64
Q

What does pepsin do?

A

Causes the breakdown of proteins into amino acid chains

65
Q

What is the end product of the stomach?

A

Food broken down into chyme

66
Q

How much of the digestive system is made up by the stomach?

A

8-10%

67
Q

How long does it take fluid to move through the stomach?

A

20-30 minutes

68
Q

How long does it take grain, pellets, and short grass to move through the stomach?

A

0.5 to 5 hours

69
Q

How long does it take long stem dry hay to move through the stomach?

A

16 hours

70
Q

When will the stomach empty?

A

When it is 2/3 full regardless whether full digestion has taken place or not

71
Q

Horses are continuous grazers. What are facts about the horse that pertain to this fact?

A

Produce acid 24 hours/day regardless
No gall bladder
Often fed once or twice a day

72
Q

How much of their body weight can horses consume of dry matter?

A

2 to 2.5%

73
Q

What is the pH of an empty stomach of a horse?

A

1.5

74
Q

What does forage act as?

A

Buffer

75
Q

What is the pH of an empty stomach of a carnivore?

A

6

76
Q

What assists with small intestine with digestion?

A

Pancreas and liver

77
Q

What does the liver produce?

A

Bile, which assist with fat absorption by the small intestine

78
Q

How frequently is bile secreted in a horse?

A

Constantly because there is no gall bladder

79
Q

What does the pancreas secrete?

A

A mixture containing enzymes and bicarb into the small intestine, which his in breaking down protein and AA chains into individual AA and soluble CHOs into simple sugars

80
Q

What percentage of fat in a diet can horses digest?

A

15-20%

81
Q

What is the small intestine responsible for?

A

Secretory H2O
Nutrient absorption
Rapid transit

82
Q

What are the difference of the small intestine in horses compared to small animals?

A

The proximal half is more secretory than absorptive for water
Even though the SI is long, the rate of passage is relatively fast

83
Q

How much of the horses total body water circulates through the GI tract on a daily basis?

A

1/2

84
Q

What is cellulase?

A

Microbial enzyme to break down fermentable fiber into simple sugars

85
Q

What is acetic acid?

A

Can be used directly by mammalian cells or used by the liver for synthesis of longer chain fatty acids for formation of triglycerides
Directly accounts for 30% of energy needs

86
Q

What happens with propionic acid?

A

Goes to liver for glucose synthesis

87
Q

What is butyric acid used by/?

A

Colonic cells

88
Q

What do proteases do?

A

Breakdown plant protein into peptides

Take in and converted into microbial protein

89
Q

What is within the anaerobic fermentation vat?

A

VFAs

Some water soluble vitamins

90
Q

How much do VFAs account for energy needs?

A

50-80%: 30% from colon, 50% from cecum

91
Q

What is the cecum?

A

Inlet and outlet near the top of the large intestine

Microbial fermentation vat

92
Q

What does grain overload cause?

A

An increase in lactic acid which can cause damage to the cecal wall
So much lactic acid can be produced that microbes eventually die off

93
Q

What happens in the cecum and colon for every 24 hours off feed?

A

Microbial populations drop by 50%

94
Q

How bog is the colon?

A

100-140 L

95
Q

What is the colon?

A

H2O reservoir

96
Q

What does the colon have an effect on during exercise?

A

Respiratory rate

97
Q

What does the large colon do?

A

Provides an additional location for fermentation of fibrous digesta and a site where absorption of the products of fermentation can occur

98
Q

How much water does an average horse at rest consume?

A

About 7 gallons

99
Q

What is the function of the small colon?

A

To absorb water and form fecal balls

100
Q

What does the rectum do?

A

Excrete feces

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