Biology 1120

Exercises 26 & 27 Lab notes

Dissection of the Male and Female Rats & Fetal Pigs

wikipedia on anatomical terms

n In performing dissections it is important to become familiar with directional terms to understand the placement of various incisions made on the animals and the location of various body parts.

n Directional terms:

· Dividing Planes

Þ Frontal Plane - divides the animal’s body along its central axis into dorsal and ventral halves

Þ Saggittal Plane - divides the animal’s body along the central axis into right and left halves

Þ Transverse Plane - divides the animal’s body into anterior and posterior ends or, superior and inferior ends or, cranial and caudal ends (in 4-footed animals) or, cranial and pedal ends (in biped animals e.g. humans)

· Other directional terms:

Þ Proximal - near to

Þ Distal - far from

Þ Lateral - toward the side

Þ Medial - toward the middle

n The two major cavities of the body are the thoracic and abdominopelvic cavities which are separated by the diaphragm which runs transversely across the body.

n Thoracic organs to be familiar with:

· Trachea

· Larynx

· Esophagus

· Thymus gland (particularly in fetal pigs)

· Thyroid gland

· Heart - with pericardial sac

· Lungs - with pleural membranes

n Abdominopelvic organs to be familiar with:

· Liver

· Gall bladder (pigs only - rats don’t have gall bladders)

· Stomach

· Pancreas

· Small intestine

· Large intestine

· Mesenteries

· Cecum (rats only)

· Spleen

· Kidneys

· Umbilical cord with Allentoic bladder (fetal pigs only)

· Urogenital system of the male rat:

Þ Scrotum

Þ Testis

Þ Epididymis

Þ Inguinal canal

Þ Spermatic cord

Þ Vas deferens

Þ Seminal vesicles

Þ Prostate gland

Þ Penis

· Urogenital system of the female rat:

Þ Vagina

Þ Uterine horns

Þ Ovaries

Þ Oviducts