Midterm Flashcards
What is the order, suborder, family, and genus of rats
rodentia
myomorpha
muridae
rattus
what is the most common rat you will see in practice
Rattus norvegicus (the norway rat)
What is the order, suborder, family, genus and species of mice
rodentia
myomorpha
muridae
mus
musculus
t/f: rodent incisors grow continuously throughout life
true. if maloccluded, they won’t wear normally and will need to be trimmed
what is the purpose of brown fat deposits in rats and mice? what are they sometimes called?
used to generate heat (“non-shivering” thermogenesis)
also called the hibernating gland, although they do not hibernate
what is unique about the rat and mouse brain
it lacks gyri and sulci
don’t confuse this for edema on necropsy
what does the harderian gland produce? when might it over-produce?
secretes porphyrin, an iron containing reddish pigment
stress causes hypersecretion (“red tears”)
t/f: rats and mice lack a gallbladder
false. the rat lacks a gallbladder, but the mouse has one
t/f: rodents cannot vomit
true
what is unique about the rat/mouse GIT
they have a large cecum which is important to digestion of plant materials
where is the opening of the urethra in female rats/mice? males?
in the genital papilla near the base of the clitoris (not in the vagina like with other animals. important for catheterization)
in the penis for males
what animals have a harderian gland?
rats, mice, and gerbils
what is a sperm plug and what is its purpose
secretions from the sex glands of male rats and mice form this plug in the vagina after mating to prevent rebreeding. it is also useful for tracking pregnancy. day 1 = the day the plug forms
you can’t find the testicles on a male rat. does this mean he has been neutered or is cryptorchid?
no. rats have open inguinal rings that allow the testes to be withdrawn into the abdomen when cold or fighting
how is the female rat’s repro system different from other rodents?
she has 2 cervices. others also have a bicornuate uterus, but with only one cervix
when is the vaginal closure membrane present in rats and mice? guinea pigs?
in rats and mice, it is present in immature females and disappears prior to sexual maturity.
in guinea pigs, it is present all the time, except when receptive to breeding or near parturition
how can you differentiate between sexes in rats and mice
anogenital distance is shorter in females than males
how many pairs of nipples do rats and mice have?
6 in rats. 5 in mice
describe the distribution of mammary tissue in rats and mice. what is the clinical relevance
widely distributed and may extend onto the lateral and dorsal areas of the abdomen and thorax. tumors on the dorsolateral aspect of the animal could be a mammary tumor
how long do rats and mice live
2-3 years for rats
1.5-3 years for mice
how much urine do rats and mice produce
3.3 mL/100g BW/day for rats
0.5-1 mL/day for mice
when are rats and mice most active
at night. nocturnal
are male or female rats/mice more aggressive
males
t/f: group housed female rats and mice often fight
false. rarely fight
describe barbering in mice. how can it be managed
social dominance may be manifested by excessive grooming of the lower mice. the dominant mouse (the one without bald spots) can be treated with N-Acetylcysteine or housed alone
how should rats and mice be fed
food provided ad libitum
good practice to measure feed consumption
standard is pelleted feed
what are the downsides to powdered/mash feed for rats and mice
may lead to incisor tooth overgrowth
may dig food out of feeder, making consumption measurement difficult
