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Flashcards in Intestine 2 (test 1) Deck (35):
1

Where does enterocyte proliferation occur?

In the Crypts

2

What are 2 compensatory reaction to enterocyte loss?

1. Flattening of remaining enterocytes 

2. Increased Mitotic rate of crypt epithelial cells 

3

The mucosal phase of digestion is mediated by WHAT?

ENTEROCYTES 

4

The delivery phase of digestion involves what?

Lymphatics and Blood 

5

The mucosal phase of digestion involves what?

Surface (microvilli) and Cellular (enterocytes)

6

The intraluminal phase of digestion involves what?

Pancreatic and Biliary: break down food 

7

What are some causes of secretory diarrhea?

Bacterial Exotoxins, Inflammatory Mediators (prostaglandins, eiconsinoids, histamine, kinins, cytokines-->influence enteric nerve reflexes)

8

How does bacterial exotoxins cause secretory diarrhea?

They affect secretion/ absorption (active cAMP and gAMP) of Na+, Cl- and therefore water

9

What is the most common cause of diarrhea in neonatal calves?

ETEC!

10

T or F

ETEC destroys enterocytes while it causes disease

FALSE, ETEC uses pili (fimbrae) to attach to the enterocytes (apical) and secrete exotoxins that cause secretory diarrhea 

11

Why does ETEC only infect neonates in the first week of their lives?

Because ETEC needs the receptors involved in colostrum absorption (FcRN) in order to attach to the enterocytes and these receptors go away quickly after the neonate is born. 

12

Why do animals die from ETEC infection?

Because of the HYPERsecretory diarrhea which results in DEHYDRATION, electorlyte imbalances, and acidosis. 

13

Where does ETEC attach or infect?

ON the apical portion of the microvilli at the FcRN receptors (think passive transfer receptors)

14

What are two effects of enterotoxins from ETEC? 

1. inhibits coupled Na-CL uptake and water absorption in the villi-cGMP pathway

2. Stimulates secretion of Cl- in crypts-cAMP pathway 

15

Where does rotavirus and coronavirus set up shop?

they infect, proliferate in, and DESTROY Mature Villous enterocytes

Leads to villous atrophy-->malabsorptive (osmotic) diarrhea 

Enterocyte damage-->exudative diarrhea 

16

How does Rota and Corona viruss cause diarrhea? What type of diarrhea is it?

Villi become denuded, contracted, and may fuse (villous atrophy)-->malabsorption (osmotic diarrhea)

Enterocyte Damage-->exudative diarrhea 

17

How do villi compensate for enterocyte damage from rota and corona viruses?

Crypt (immature) enterocytes proliferate in response-->villi will be normal again in ~7 days

18

When would you see Rotavirus in calves?

Between 0-2 weeks of age

19

When would see coronavirus in calves?

Between 0-3 weeks

20

T or F

Coronavirus and Rotavirus desrupt the crypts in the small intestine

FALSE, They attack mature enterocytes on the apical portion of the villi, thus the crypt cells remain intact 

A image thumb
21

What cells does rotavirus and coronavirus attack and where?

They attack MATURE enterocytes in the Small intestine leading to osmotic (loss of absorptive surface area)  and exudative diarrhea (mucosal damage)

22

What is specific to rotavirus that corona virus does not do?

Rotavirus additionally impairs disaccharidases in the brush border-->leading to maldigestion of carbohydrates 

23

T or F

Cats can be infected with parvovirus

TRUE, but it is called panleukopenia, cat distemper, or feline enteritis. 

24

What are clinical signs of parvo infection?

Diarrhea-Bloody, Fetid (FOUL smelling)

Vomiting

Fever

Depression

Dehydration 

25

Define fetid

Something smelling extremely unpleasant

26

What cells does parvovirus infect?

Rapidly DIVIDING cells 

Intestinal crypts-->diarrhea

Bone Marrow-->panleukopenia 

Lymphoid follicles-->lymphopenia 

27

Where does parvovirus first repicate?

In the lymphoid tissue of the oropharynx-->viremia-->dissemination to rapidly dividing cells of GI tract, bone marrow

28

Parvo infection leads to loss of enterocytes. What three events occur because of this damage?

1. loss of absorptive surface area-->malabsorption--> osmotic diarrhea

2. loss of fluid, electrolytes, plasma proteins into the lumen--> exudative diarrhea

3. loss of mucosal barrier (ulceration)-->secondary bacteremia, endotoxemia 

29

Parvo infections in young animals can lead to additional lesions, what are they?

Puppies infected at <2week old: Myocarditis (+/- lesions in the liver, kidney, lung, blood vessels

Kittens infected in Utero: congenital cerebellar hypoplasia 

30

T or F

With parvo infection you will see defined crypts

False, parvo attacks the rapidly dividing cells found in the crypts leading to diffuse villous atrophy and crypt dropout 

A image thumb
31

What will you see grossly with parvo infection?

The small intestine will be segmentally dark red

32

what will you see microscopically with parvo infection?

Severe villous atrophy

crypt dropout 

33

Coccidiosis is an intracellular or extracellular parasite?

Intracellular 

34

What type of enterocolitis do you see in calves, kittens, puppies, lambs, kids, piglets and poultry with coccidiosis?

Calves, Kittens, puppies-->hemorrhagic enterocolitis

Lambs, kids-->proliferative enterocolitis 

Piglets-->fibronecrotic enterocolitis 

Poultry-->hemorrhagic/fibrinonerotic enterocolitis 

RARE in horses 

35

What 3 things help determine the severity of coccidiosis disease?

1. Infective dose

2. Host immune status

3. site of development (species virulence)

-villi vs. crypts 

Lyse enteroctyes