Exercise 47- External Features & Rat Skeletal System
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Created by:
Kenzie_Davis on November 19, 2011
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56 terms
Terms | Definitions |
|---|---|
 What features of rats make them a good experimental model to learn about factors that affect humans? | small, familiar, and easily bred for experiments |
| Dorsal | toward the upper surface (back) |
| Ventral | toward the lower surface (belly) |
| Anterior | toward the head |
| Posterior | toward the tail |
| Medial | toward the midline of the body |
| Proximal | toward the end of the appendage nearest the body |
| Lateral | toward the midline of the body; toward the side |
| Distal | toward the end of the appendage farthest from the body |
| Frontal plane | divides body into dorsal & ventral halves; 2 dimensional plane parallel to the anterior-posterior axis & perpendicular to the dorsal-ventral axis |
| Transverse plane | a cross section; 2 dimensional plane perpendicular to the anterior-posterior axis of the body |
| Sagittal plane | divides body into left & right halves; 2 dimensional plane parallel to the anterior-posterior axis & parallel to the dorsal-ventral axis |
| cranial region | head |
| cervical region | neck |
| pectoral region | area where forelegs attach |
| thorax | chest region |
| abdomen | belly |
| pelvic region | area where hind legs attach |
| pelage | hairy coat that covers most of the rat's body |
| vibrissae | tactilely (related to touch) sensitive "whiskers" on the face |
| nares | nostrils; located at anterior end of head |
| incisors | subterminal mouth has a cleft that exposes large front teeth |
| large pupils | adaptation to nocturnal life; eyes bulge from head and enable the rat to see in almost all directions |
| nictitating membrane | located at inside corner of the eye; this translucent membrane may be drawn across the eyeball for protection |
| eyelids | similar to those found in humans |
| pinna | external ear |
| auditory meatus | ear canal |
| teats | 6 pairs of these located on ventral surface |
| tail | located posteriorly (caudally) and is covered w/ hair & scales |
| anus | ventral to the base of the tail |
| clitoris | a small protuberance from which the urinary aperture opens lies just caudal to the last pair of teats in a female |
| vaginal orifice | just caudal to the clitoris; located in a small depression called the vulva |
| scrotal sacs | in males; lie on each side of the anus & contain testes, which produce sperm cells |
| prepuce | a bulge of skin surrounding the penis |
| preputial orifice | where penis can be extended from the prepuce |
| urogenital orifice | located at the end of the penis; where both urine & sperm cells exit the body |
| quadruped | rat has 4 legs w/ 4 digits and a vestigial thumb on each foot |
| plantigrade | a stance in which both the sole & heel of a rat's foot contact the ground as indicated by the lack of hair from the toes to the heel |
| digitigrade | animals that walk on their toes |
| mandible (part of skull) | lower jaw; contains a broad, flat surface for muscle attachment |
| maxilla (part of skull) | upper jaw |
| zygomatic arch (part of skull) | place where some jaw muscles pass under and attach to the lateral surface of the cranium |
| cranium (part of skull) | braincase |
| axial skeleton | formed by the skull & vertebral column |
| 5 groups of vertebral column | cervical, thoracic, lumbar, sacral, caudal vertebrae |
| atlas & axis | 2 cervical vertebrae; form a versatile joint and allow for a variety of head movements |
| ribs | extend from thoracic vertebrae; form an enclosure (rib cage) |
| caudal vertebrae | form a long tail |
| pectoral girdle | where bones of anterior appendages (forelegs) attach |
| pelvic girdle | where bones of the posterior appendages (hind legs) attach |
| appendicular skeleton | bones of forelegs & hind legs |
| integument | skin |
| genitals | external sex organs |
| fascia | connective tissue that is tough yet flexible |
| cutaneous trunci | thin sheets of muscle that attach to the skin |
| brown fat | a deposit of fat between the shoulder blades that is specialized for heat production if the animal is stressed by low temperatures |
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