Seminar - Anatomy and Physiology Flashcards
What is the vertebral formula of mice and rats?
C7, T13, L6, S4, Cocc. 28 (mice) 27-31 (rats)
How many ribs? How many sternal, asternal, and floating?
7 sternal, 6 asternal, 3 floating.
Why is the rat commonly used to model rotator cuff tears?
Well-formed clavicular brace with shoulder anatomy similar to humans.
Describe bone maturation and growth plate fusion in rats. In mice.
Rat bone maturation rate slower than most mammals, ossification not complete until >1 year of age. Growth plates do not fuse in rats. Fusion is variable and incomplete in mice, depending on strain and genotype
Which animals lack haversian systems? (3)
Mice, rats, and hamsters
Dental formula of mice and rats
2 (I 1/1, M 3/3) = 16 teeth total
Describe teeth in rodents.
No deciduous teeth. Incisors are open rooted. Enamel layer on rostral surface of incisors, gives teeth pigment.
Where is the incisive foramina?
Communicates between mouth and nose.
Do rodents have tonsils?
No, have nasal-associated lymphoid tissue.
Name the three salivary glands, their products, and where they open. Why is this important to disease?
Parotid - Serous, diffuse, drains opposite lower molars.
Submaxillary - Mixed, drains posterior lower incisors.
Sublingual - Mucous, drains near submaxillary.
Sendai only infects serous glands.
Describe the sexual dimorphism of the salivary glands.
Male submaxillary gland has more prominent secretory granules. Female has fewer secretory granules in ductal epithelial cells. Submandibular and parotid salivary glands are larger in males as well.
Describe the structure of the esophagus
Entire esophagus composed of striated muscles with keratinized/cornified surface
Describe gastric juice secretion
Continuous, not dependent on food intake. Rate is slower in mice than rats, takes longer to induce gastric ulcers in mice than rats.
What are Paneth cells? What are Brunner’s glands? Which one differs between mice and rats?
Paneth cells produce lysozyme, which may regulate flora. Brunner’s glands produce mucin and bicarbonate to protect the mucosa. Paneth cell granules in SI crypts are large in mice and humans but small in rats.
Describe the cecum in rats.
Rats have no internal septae, have inner constriction dividing cecum into apical and basilar sections. Apical portion only contains lymphoid tissue, like vermiform appendix of man.
Why are mice prone to rectal prolpase?
Short rectum
When are thickened bowel walls normal?
Pregnant and lactating females due to physiological mucosal hyperplasia.
Describe lobation of mouse and rat liver.
Mouse: Median, left, right, and caudate lobe. Gallbladder in cleft of median lobe.
Rat: Median, right lateral, left, and caudate lobe. Bile ducts from each lobe come together to form common bile duct, which drains into descending duodenum. Cannot concentrate or store bile.
Describe common findings in mouse livers. How does this differ from the rat liver?
Anisokaryosis, polykarya, and karyomegaly present at all ages, but increase with age and disease. Extra-medullary hematopoiesis commonly seen, especially in younger mice. Fat vacuoles common.
Rat hepatocytes are more uniform.
Describe the pancreas in mice and rats. Where does the pancreatic duct open in mice and rats? How can pancreatic juice be collected in rats?
More diffuse than in most other mammals.
Rats: Pancreatic duct opens into lower part of common bile duct. Collection via ligation of common bile duct near origin with cannulation near orifice.
Mouse: Pancreatic duct drains into duodenum at greater duodenal papilla.
Where are Islets of Langerhans found in the pancreas? When do their numbers increase?
Scattered irregularly throughout pancreas. Increase in number during pregnancy.
What is Steno’s gland, where is it found, what is its function, and hos is it regulated?
Lateral nasal gland, the largest nasal gland in rats. Surrounds maxillary sinuses and extends into the lateral wall. Glands empty into nasal vestibule. Regulates viscosity of mucus and humidifies inspired air. Homologous to salt gland in marine birds. May be regulated by nervous system so that rapid adjustment of secretory activity in response to inspired air is possible.
What are the two divisions of the olfactory system?
Main: Nasal cavity olfactory system
Accessory: Vomeronasal. Receptors for pheromones, prominent in rodents.
Describe lung lobation
Four right lobes, one left lobe.
Where is cartilage present in the airways?
Only in extrapulmonary airways.
What is the pulmonary branching patten in mice and rats?
Monopodial (branch forms one smaller daughter segment at an angle) as opposed to dichotomous in humans (two equal daughter segments)
What is unique about the respiratory epithelium of rats? How does this impact disease presentation?
Rats have serous cells in their respiratory epithelium. Sendai can be found in trachea.
What is unique about the epithelial lining of the bronchioles in the rat?
Epithelial lining in bronchioles remains high cuboidal on side adjacent to arteriole, opposite side progressively decreases in height.
What is unique about submucosal/bronchial glands in the mouse?
They are rare or absent in the mouse. Epithelial surface cell produces a secretion of lower viscosity of than that of the mucus cell.
Describe the lungs of neonates.
Lungs are immature with no alveoli nor alveolar ducts. Restructuring and development occurs post-natally. Gas exchange occurs in smooth-walled channels and alveolar sacs.
What is unique about the pulmonary vein?
Contains cardiac muscle, not to be confused with medial hypertrophy.
What lab species have precapillary anastomoses between bronchial and pulmonary arteries in the hilar region?
Rats, GPs, opposums, man