Unit 4: The Rat Flashcards
term referring to both rats and mice
Murine (both from subfamily muridae)
rats and mice belong to which order
rodentia (comes from latin word Rodere meaning to gnaw)
rats reach sexual maturity at ab what age
2 months
why rats are unable to vomit
ridge covering opening of esophagus
define teratology
study of abnormal development/ birth defects
when does epiphysus (epiphyseal plates) in rats close?
never, constantly growing
__ digits on front feet
__ digits on back
4 front
5 back
rats are hypsodontic meaning
their teeth are constantly growing
gland behind eyes in rats that contains porphyrin
Harderian gland
what causes rat tears to be red
porphyrin (red pigment) excreted by harderian gland
purpose of porphyrin in rat tears
pheromone and lubricant
a rat that stops grooming is a sign that
the rat is unhealthy in some way
which is longer in rats, bottom or top incisors
bottom
define chromodacryorrhea and possible causes
excessive flow of pigmented tears
stress or disease
rats are monogastric and ferment where
cecum (hind-gut fermenters)
rats are coprophagic, meaning
they eat their own feces to regain nutrients
t or f, male and female rats have 6 pairs of nipples
F; male rats do not have nipples (females do have 6 pairs)
rats are prone to what kind of tumors
mammary tumors; bc they have extensive mammary tissue going from over the shoulders to the caudal perianal region
how to sex rats
observe anogenital distance (males is twice as long)
females develop teats (5-15 days)
female rats can be bred how long after parturition
24 hrs (have postpartum estrus)
define an inbreeding scheme
related members of specific strain bred for minimal genetic variation
define outbreeding scheme
unrelated animals of same stock are bred
the outbred stock we have
Long-Evans
define malocclusion
overgrowth of teeth
low humidity can cause
ringtail
resp infection that causes thick mucopurulent nasal/occular discharge
mycoplasma
causal agents of rat pneumonia
pasteurella or streptococcus
signs of otitis externa following mycoplasm infection
tortocolis (wry-neck/head tilt), circling, sweet-foul smelling drainage
advanced= facial nerve paralysis or eye blinking
a kind of tumor usually benign in rats and will most likely grow back if removed
mammary fibroadenoma
how tyzzer’s disease is spread
fecal-oral route, caused by poor sanitation
causal agent of tyzzers disease
clostridium piliforme
tyzzers disease produces disease in ____ and ____
what species are susceptible?
liver and heart
all species of lab animal susceptible
virus that compromises immune system, is seriously contagious, and usually subclinical
Sendai virus
how to measure gavage length
tip of nose to last rib
what is an IP injection
Intraperitoneal injection; in abdomen
needle size for rat venipuncture
26-27g
most lab rats are related to what species of rat
rattus norvegicus
rats have a fusiform body meaning that
they have a spindle-shaped body
define an inbred strain
group of descendants of at least 20 brother-sister or parent-sibling matings
what the SHR strain is usful for
Spontaneous hypertensive rat; good for studying high blood pressure
list the 3 outbred stocks
Sprague-Dawley(SD), Long-Evans(LE), Wistar (WI)
which outbred stocks are albinos, how to distinguish
SD and WI, WI have wider heads and longer ears
list uses of rats in research
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
rat dental formula
I 1/1, C 0/0, M3/3 (6 on top, 6 on bottom)
rat lungs have __ lobes in the right and __ lobes in the left
4 lobes right (larger), and only 1 on the left
how long is gestation in rats
20-22 days
list the 2 mating systems
monogamous (1 male 1 female) and polygamous (1 male many females)
what age female rats develop nipples
5-15 days
what are pinworms and how to identify
internal parasite, commonly LI, inspect anus and fecal float (also causes severe itching)
genus species of rat lice
Polyplax serrata
how to restrain rat
grab by base of tail, may “barrel-hold” by encircling thorax with index and middle finger
difference between IP injection in rats and mice
rats- give in lower left quadrant to avoid cecum
mice- give in right side to avoid spleen
what may happen if we hit the sciatic nerve causing lameness
rat may begin to self mutilate
how to draw blood from rat saphenous vein
nick w 23g needle, drip into container 1/4-1/2cc at most (syringe would flatten vein)
most human method of euthanizing a rat
isoflurane overflow until death
other than an overflow of isoflurane, what other ways do we euthanize rats
barbiturate overdose followed by CO2 chamber to asphixiate
can also decapitate if tissue or body fluid must be uncontaminated for research (approved by iacuc)
Nearly ___ % of mammals are rodents
40%
Rat tails make up __% of their body in length
85%
