Biology Flashcards
Describe the appearance of the Black and Norway rat.
Black: Smaller, thick ears, tail 85% length of body.
Norway: Larger ears, tail longer than body.
Name the two hair classes and describe hair growth.
Long (sparse) and short hairs. Hair growth in the young is cyclic with resting and growing periods of 7 days
How many teats and where are they located.
6 pairs, three pectoral, three abdominal
Rank the size of SD, Wistar, and F-344
SD > Wistar > F-344
Rats have what type of eyes? How are they moistened? What is a special characteristic of this secretion?
Exophthalmic eyes. Moistened by secretions from lacrimal gland and medially located Harderian gland. Porphyrins fluoresce
What venous structure is present adjacent to the rat eye? How does this differ from the mouse?
Rat: Orbital venous plexus
Mouse: Orbital venous sinus
Describe vision in the rat. Number of colors, what spectrum they can see, and what spectrum they are insensitive to.
Dichromatic with 2 cones, 1 of which sees in UV. Insensitive to long wavelengths, i.e. dim red light at 625 nm, although it can affect photoperiod.
What is the hearing range of a rat? Where are they most sensitive? What is the ultrasonic range?
250Hz - 80 kHz.
Most sensitive at 8-32 kHz
Ultrasonic = 22 - 80kHz
Vertebrae formula
C7, T13, L6, S4, Caud 27-30
Costal cartilage?
No true costal cartilage
Tibia and fibula structure
Separate proximally, fused distally
Dental formula
2(I 1/1, M 3/3)
Name the three salivary glands, their products, and how one differs from the mouse.
Parotid: Serous
Submandibular: Mixed (seromuscular in mouse)
Sublingual: Mucous
Where is brown fat/multilocular adipose tissue found?
Ventral and lateral portions of the neck
What structures are present on each aspect of the colon?
Ascending colon = Oblique mucosal ridges
Transverse and descending = Longitudinal mucosa folds
What are the four liver lobes? Where are each visible on necropsy?
Right lateral, left (visible beneath median), median (visible on ‘top’), caudate (around esophagus)
Describe passage of bile and pancreatic products.
No gallbladder. Bile from each lobe forms a common bile duct. Pancreatic ducts empty into common bile duct.
Where is Steno’s gland located? What does it produce?
Maxillary recess/sinus between maxillary bone and lateral laminae of ethmoid bone contains lateral nasal gland (Steno’s). Similar to salivary gland, produces watery product discharged at rostral end of nasal turbinates to regulate viscosity of mucus layer overlying nasal epithelium.
Describe lung structure.
Single left lobe, four right lobes (cranial, middle, accessory, caudal)
Describe two unique features of the respiratory system.
Pulmonary vein contains cardiac muscle continuous with heart. No adrenergic supply to bronchial muscles - bronchoconstriction controlled by vagal tone.
Describe the male accessory sex glands.
Vesicular glands = seminal vesicles. Prostate = dorsocranial (coagulating), dorsolateral, and ventral.
Bulbourethral = Cowper’s. At base of penis
Describe uterus
Bicornuate, two horns and cervices
Describe kidney structure. What unique structure predisposes to what research use?
Unipapillate. Superficial nephrons in the renal cortex make rat kidney a model for investigating nephron transport in an in vivo micropuncture system.
Name four unique characteristics of the brain.
Lissencephalic
Large olfactory bulbs
Paraflocular lobes of cerebellum in deep sockets of the periotic capsule of skull
Ventricular system lacks foramen of Magendie
