Mice Intro Flashcards
Are rats of the genus Rattus and mice of the genus Mus bred for use in research covered by USDA regulation
No
Are rats of the genus Rattus and mice of the genus Mus bred for use in research covered by PHS policy
Yes
Do mice have a gallbaldder
Yes (unlike rats)
The red staining around a mouse’s mouth and nose is due to the accumulation of _____ produced by the _______ gland, a lacrimal gland
accumulation of porphyrins produced by the Harderian gland
A mouse in a recent shipment of animals appears dehydrated and you want to give SQ fluids. What is the max volume you can give to an average size mouse?
2-3 ml, up to 0.5 ml/site
Continent of origin for the lab mouse?
Asia (Old World)
The laboratory mouse genome is a mixture of what 2 species?
M. musculus and M. domesticus
What is the difference between axenic, gnotobiotic, SPF, and conventional mice?
Axenic- germ free
Gnotobiotic- only defined GI flora, no other bacteria
SPF- specific pathogen free, but normal commensal flora
Conventional- microbes not defined, can have pathogenic organisms
What is the origin of the C3H strain?
From a cross of a Bagg albino female and a DBA male by Strong in 1920.
What is the color of C3H mice?
Agouti
Typical adult mouse weight
20-40 grams
Daily water consumption (ml/d) for a mouse?
6-7 ml/day
Daily food consumption (g/d) for a mouse?
4-5 g/day
Unique traits of murine urine include?
Urine is highly concentrated with large amounts of protein (0.5-1.0 ml in 24 hours)
Diploid chromosome number of the lab mouse? (2n= ?)
40
Age of puberty for mice?
Puberty ~ 35 days (range 28-49 days)
Mice are polyestrous and cycle every ___ days
4-5
What is the significance of a vaginal plug in mice?
Denatured seminal fluid and sperm that signifies copulation has occurred.
80-90% of mice with vaginal plugs become pregnant
When does the first post partum estrus occur?
12-24 hours after parturition
When does the post-lactation estrus occur?
2-4 days post weaning
Mouse gestation period
17-21 days
Describe the number and location of mammary glands in the mouse.
5 pair of mammary fat pads just below the skin. 3 thoracic, 2 inguinal
Each has exterior nipple
Cohoused male mice may fight. Typical fight injuries occur on which parts of the body?
Scrotal area, base of tail
C57BL/6 mice are predisposed to what dermatological condition?
Idiopathic (ulcerative) dermatitis
Also barbering
What the genus and species anme of the two major fur mites seen in lab mice?
Myobia musculi and Myocoptes musculinus
Name the genuses of two common types of pinworms seen in mice.
Syphacia, Aspicularis
Ringtail is associated with what environmental condition?
Low relative humidity
Dental formula for mice
I 1/1 C 0/0 P 0/0 M 3/3
Describe the approach for an IP injection in mice.
Lower right abdomen, between midline and hind leg
Why are IM injections not recommended in mice?
Small muscle volume, injection can cause muscular atrophy, nerve damage
Name six sites for blood collection in mice.
Medial saphenous vein Lateral saphenous vein Lateral tail vein Submandibular Retroorbital Cardiac exsanguination
Name 4 sites that are acceptable for blood collection awake in mice
Medial saphenous vein
Lateral saphenous vein
Lateral tail vein
Submandibular
Ear punches or ear tags used for ID in mice should be placed where on the ear?
should be placed approximately 3 mm from the edge of the ear pinna.
What 2 anatomical sites are commonly tattooed for individual mouse identification?
Tails and footpads
When is toe clipping an acceptable means of identification in mice?
Only used when no other individual identification is feasible. 2011 Guide
At what age should tail ampuation for mouse genotyping occur?
2-3 weeks of age
What is the maximum amount of tail that should be amputated for genotyping?
2 mm
How allometric scaling of drug doses performed?
Based on estimation of basal metabolic rate (BMR)
BMR = k(Wkg0.75)
Wkg= body weight in kilograms
k= “species factor”
Which “old school” anesthetic is associated with peritonitis and a dynamic ileus?
Choral hydrate
Which “old school” anesthetic is carcinogenic and, thus, unsuitable for survival surgeries?
Urethane
This “old school” anesthetic was sold under the proprietary name Avertin and decomposes into irritating and toxic products if stored at room temperature and exposed to light?
Tribromoethanol
Major disadvantages of pentobarbital for anesthesia?
Controlled (CII), poor analgesia, risk of perivascular necrosis
According to ______’s Law a small change in airway diameter leads to big changes in airway resistence.
Poisseille’s Law
Reducing the airway diameter of a rodent by 1/2 by ET tube placement, increases the resistance by how much?
16x
What important consideration is essential for intubated small mammals?
Must be on ventilation
Define major surgery
Major –“penetrates and exposes a body cavity, produces substantial impairment of physical or physiologic function, or involves extensive tissue dissection or transection”
Define minor surgery
“does not expose a body cavity and causes little or no physical impairment”
True or false: aseptic techique in rodents requires the use of a sterile gown and gloves.
False, but tissue handling should be done with sterile istrument tips
What is the most appropriate method for monitoring depth of anesthesia in rodents?
Toe pinch test –firm pinch of the foot or toe should not elicit any movement in an adequately anesthetized animal
Which rodent spp should not have anesthetic depth assessed by the toe pinch method?
Guinea pigs, toe pinch reflex present at surgical planes of anesthesia
What is the grimace test in mice?
A pain assessment tool
