Zoo_logy_1576

snail. 1. (Science: zoology) Any one of numerous species of terrestrial air–breathing gastropods belonging to the genus helix and many allied genera of the family Helicidae. They are abundant in nearly all parts of the world except the arctic regions, and feed almost entirely on vegetation; a land sanil.

Procedure: Exposing the bones of the leg
Carefully tease away the biceps femoris and gastrocnemius to expose the 3 leg bones: Tibia, Fibula, and Femur and the small patella (kneecap). You can also see the ligaments around the knee that attach the bones of the lower leg to the femur and the achilles tendon which attaches the gastrocnemius to the ankle.

Note that the joint of the hip is called a ball and socket joint. Examine how the bones fit into the pelvis.

Structures of the Head and Neck

Locate the salivary glands, which on the sides of the neck, between muscles. Carefully remove the skin of the neck and face to reveal these glands. Salivary glands are soft spongy tissue that secrete saliva and amylase (an enzyme that helps break down food). There are three salivary glands - the sublingual, submaxillary, and parotid.

Find the lymph glands which lie anterior to the salivary glands. Lymph glands are circular and are pressed against the jaw muscles. They are not always visible in the rat.

Tease away the muscles of the neck to reveal the trachea. The trachea is identifiable by its ringed cartilage which provides support. The esophagus lies underneath the trachea, though it is easier to locate in the abdominal cavity where it enters the stomach.

Locate the larynx, which is just anterior to the trachea. The larynx is the voice box, and it allows rats to making squeaking noises.

Identify the following muscles and place a different colored pin in each.

1. Biceps brachii - located on the anterior surface of the humerus.
2. Triceps brachii - located on the sides and back of the upper arm.
3. Spinotrapezius - located across the dorsal thoracic region of the rat.
4. Latissimus dorsi - located posterior (and partially covered) by the spinotrapezius.
5. Biceps femoris - located on the side of the thigh, in two bundles
6. Tibialis Anterior - located on the front of the leg.
7. Gastrocnemius - located on lower leg, bulk of the calf muscle. Attaches to heel by the Achilles Tendon.
8. External Oblique - located on the sides of the abdomen.
9. Gluteus Maximus - located on the lower back and rear.
10. Pectoralis Major/Minor - located in chest

The Mouth

Vomerine Teeth: Used for holding prey, located at the roof of the mouth

Maxillary Teeth: Used for holding prey, located around the edge of the mouth

Internal Nares (nostrils) breathing, connect to lungs

Eustachian Tubes: equalize pressure in inner ear

Glottis : Tube leading to the lungs

Esophagus: Tube leading to the stomach

Tongue: Front attached, aids in grabbing prey

Tympanic Membrane: eardrum, located behind eyes

Nictitating Membrane: clear eyelid, protects the eye

The Organs of the Abdominal Cavity

Peritoneum: Spiderweb like membrane that covers organs

Stomach: First site of chemical digestion, breaks down food

Pyloric Sphincter - valve between stomach and small intestine

Liver: Makes bile (aids in digestion)

Gall bladder: Stores bile

Esophagus: Tube that leads to the stomach

Pancreas: Makes insulin (aids in digestion)

Small Intestine(duodenum, jejunum and ileum): absorb nutrients from food

Mesentery: Holds coils of the small intestine together

Large Intestine: Collects waste, absorbs water

Cloaca: "Sewer": eggs, s***m, urine and f***s enter this area

Spleen: Part of circulatory system, stores blood

The Urogenital System
urogenital system

Kidneys (D): Filter Blood

Ureters (G): Carry urine from kidneys to bladder

Te**es (C): Make s***m

Oviducts (B): eggs travel through these

O***y: makes eggs (A) - o***y is often too small to see, but eggs are visible

Urinary Bladder (F): Stores Urine

Cloaca (E): Where s***m, eggs, urine, and f***s exit.