Unit 4: The Rat

Question 1

term referring to both rats and mice

Answer 1

Murine (both from subfamily muridae)

Question 2

rats and mice belong to which order

Answer 2

rodentia (comes from latin word Rodere meaning to gnaw)

Question 3

rats reach sexual maturity at ab what age

Answer 3

2 months

Question 4

why rats are unable to vomit

Answer 4

ridge covering opening of esophagus

Question 5

define teratology

Answer 5

study of abnormal development/ birth defects

Question 6

when does epiphysus (epiphyseal plates) in rats close?

Answer 6

never, constantly growing

Question 7

__ digits on front feet

__ digits on back

Answer 7

4 front

5 back

Question 8

rats are hypsodontic meaning

Answer 8

their teeth are constantly growing

Question 9

gland behind eyes in rats that contains porphyrin

Answer 9

Harderian gland

Question 10

what causes rat tears to be red

Answer 10

porphyrin (red pigment) excreted by harderian gland

Question 11

purpose of porphyrin in rat tears

Answer 11

pheromone and lubricant

Question 12

a rat that stops grooming is a sign that

Answer 12

the rat is unhealthy in some way

Question 13

which is longer in rats, bottom or top incisors

Answer 13

bottom

Question 14

define chromodacryorrhea and possible causes

Answer 14

excessive flow of pigmented tears

stress or disease

Question 15

rats are monogastric and ferment where

Answer 15

cecum (hind-gut fermenters)

Question 16

rats are coprophagic, meaning

Answer 16

they eat their own feces to regain nutrients

Question 17

t or f, male and female rats have 6 pairs of nipples

Answer 17

F; male rats do not have nipples (females do have 6 pairs)

Question 18

rats are prone to what kind of tumors

Answer 18

mammary tumors; bc they have extensive mammary tissue going from over the shoulders to the caudal perianal region

Question 19

how to sex rats

Answer 19

observe anogenital distance (males is twice as long)

females develop teats (5-15 days)

Question 20

female rats can be bred how long after parturition

Answer 20

24 hrs (have postpartum estrus)

Question 21

define an inbreeding scheme

Answer 21

related members of specific strain bred for minimal genetic variation

Question 22

define outbreeding scheme

Answer 22

unrelated animals of same stock are bred

Question 23

the outbred stock we have

Answer 23

Long-Evans

Question 24

define malocclusion

Answer 24

overgrowth of teeth

Question 25

low humidity can cause

Answer 25

ringtail

Question 26

resp infection that causes thick mucopurulent nasal/occular discharge

Answer 26

mycoplasma

Question 27

causal agents of rat pneumonia

Answer 27

pasteurella or streptococcus

Question 28

signs of otitis externa following mycoplasm infection

Answer 28

tortocolis (wry-neck/head tilt), circling, sweet-foul smelling drainage advanced= facial nerve paralysis or eye blinking

Question 29

a kind of tumor usually benign in rats and will most likely grow back if removed

Answer 29

mammary fibroadenoma

Question 30

how tyzzer's disease is spread

Answer 30

fecal-oral route, caused by poor sanitation

Question 31

causal agent of tyzzers disease

Answer 31

clostridium piliforme

Question 32

tyzzers disease produces disease in ____ and ____ | what species are susceptible?

Answer 32

liver and heart | all species of lab animal susceptible

Question 33

virus that compromises immune system, is seriously contagious, and usually subclinical

Answer 33

Sendai virus

Question 34

how to measure gavage length

Answer 34

tip of nose to last rib

Question 35

what is an IP injection

Answer 35

Intraperitoneal injection; in abdomen

Question 36

needle size for rat venipuncture

Answer 36

26-27g

Question 37

most lab rats are related to what species of rat

Answer 37

rattus norvegicus

Question 38

rats have a fusiform body meaning that

Answer 38

they have a spindle-shaped body

Question 39

define an inbred strain

Answer 39

group of descendants of at least 20 brother-sister or parent-sibling matings

Question 40

what the SHR strain is usful for

Answer 40

Spontaneous hypertensive rat; good for studying high blood pressure

Question 41

list the 3 outbred stocks

Answer 41

Sprague-Dawley(SD), Long-Evans(LE), Wistar (WI)

Question 42

which outbred stocks are albinos, how to distinguish

Answer 42

SD and WI, WI have wider heads and longer ears

Question 43

list uses of rats in research

Answer 43

dental research (rat molars resemble humans), toxicology studies (cant vomit), bred to be susceptible to hypertension, diabetes, cataracts or obesity, behavioral studies (bc ability to adapt to new environments), also audiology oncology teratology gerontology endocrinology and immunology

Question 44

rat dental formula

Answer 44

I 1/1, C 0/0, M3/3 (6 on top, 6 on bottom)

Question 45

rat lungs have __ lobes in the right and __ lobes in the left

Answer 45

4 lobes right (larger), and only 1 on the left

Question 46

how long is gestation in rats

Answer 46

20-22 days

Question 47

list the 2 mating systems

Answer 47

monogamous (1 male 1 female) and polygamous (1 male many females)

Question 48

what age female rats develop nipples

Answer 48

5-15 days

Question 49

what are pinworms and how to identify

Answer 49

internal parasite, commonly LI, inspect anus and fecal float (also causes severe itching)

Question 50

genus species of rat lice

Answer 50

Polyplax serrata

Question 51

how to restrain rat

Answer 51

grab by base of tail, may "barrel-hold" by encircling thorax with index and middle finger

Question 52

difference between IP injection in rats and mice

Answer 52

rats- give in lower left quadrant to avoid cecum | mice- give in right side to avoid spleen

Question 53

what may happen if we hit the sciatic nerve causing lameness

Answer 53

rat may begin to self mutilate

Question 54

how to draw blood from rat saphenous vein

Answer 54

nick w 23g needle, drip into container 1/4-1/2cc at most (syringe would flatten vein)

Question 55

most human method of euthanizing a rat

Answer 55

isoflurane overflow until death

Question 56

other than an overflow of isoflurane, what other ways do we euthanize rats

Answer 56

barbiturate overdose followed by CO2 chamber to asphixiate | can also decapitate if tissue or body fluid must be uncontaminated for research (approved by iacuc)

Question 57

Nearly ___ % of mammals are rodents

Answer 57

40%

Question 58

Rat tails make up __% of their body in length

Answer 58

85%