Rat Practical: Internal Organs

Question 1

*Submaxillary salivary gland

Answer 1

appearance: roughly oval, large, elongate
function: secrete saliva that lubricates food and contains amylase

Question 2

*Thyroid gland

Answer 2

appearance: two lobes of gray or brown swelling on either side of the trachea; lays beneath the sternohyoid muscles
function: secretes thyroxin that regulates the metabolic rate of the body. The two lobes are connected by a narrow band of tissue known as the isthmus of the thyroid.

Question 3

*Trachea

Answer 3

appearance: composed of a series of incomplete rings of cartilage forming a tube.
function: conducts air to and from the lungs

Question 4

*Esophagus

Answer 4

location: pierces the diaphragm
function: conducts food from the mouth to a muscular enlargement of the digestive tract (called the stomach)

Question 5

*Thymus gland

Answer 5

location: lies directly over the upper part of the heart
function: functions in the developing immune system and is larger in young rats than in old rats.

Question 6

*Right/Left atrium

Answer 6

function: receives blood from the veins

Question 7

*Ventricles

Answer 7

function: pumping chambers of the heart

Question 8

*Diaphragm

Answer 8

function: thin layer of muscle, separates the thoracic cavity from the abdominal cavity.

Normal contraction of the diaphragm helps breathing and avoid abnormal twitching

Question 9

*Right/Left lungs

Answer 9

function: where air enters from the bronchial tubes branching from the trachea

Question 10

alveoli

Answer 10

function: thin-walled air sacs where gas exchange occurs

Question 11

coelom

Answer 11

body cavity where viscera is suspended

Question 12

viscera

Answer 12

internal organs

Question 13

peritoneum:

what is it? In what 4 regions does it occur?

Answer 13

membranous tissue that covers the abdominal cavity and viscera; occurs in 4 regions:

1. parietal peritoneum
2. visceral peritoneum
3. mesenteries
4. Omentia

Question 14

Parietal peritoneum

Answer 14

covers the walls of the abdominal cavity

Question 15

visceral peritoneum

Answer 15

covers the internal organs

Question 16

mesenteries

Answer 16

thin membranes continuous between the parietal and viscera peritoneum. They attach the internal organs to the dorsal body wall.

Question 17

omentia

Answer 17

are thin membranes extending from the visceral peritoneums and connect organ to organ.

Question 18

*Liver

Answer 18

location/appearance: dark-colored organ suspended just under the diaphragm.

functions:
- produces bile to help digeszt fat
- storing glycogen
- transforming nitrogenous wastes into less harmful substances
- transforming digested nutrients into various molecules needed for the body

Question 19

What are the four parts of the liver?

Answer 19

1. Median/ cystic lobe
2. Left lateral lobe
3. Right lateral lobe
4. Caudate lobe

Question 20

Median/cystic lobe

Answer 20

located atop the organ. There is a cleft in its central part.

Question 21

Right lateral lobe

Answer 21

is partially divided into an anterior and posterior lobule, is smaller than the left lateral lobe

Question 22

Caudate lobe

Answer 22

is small, folds around the esophagus and stomach, and appears to be in two small sections seen most easily when the liver is raised.

Question 23

*Stomach

Answer 23

location: left side just under the diaphragm

function:

• food storage
• physical breakdown of food
• initial enzymatic digestion of protein

Question 24

cardiac sphincter

Answer 24

entrance of the esophagus to the stomach

Question 25

pyloric sphincter

Answer 25

attachment of stomach to intestines

Question 26

*spleen

Answer 26

location: attached to the greater curvature of the stomach
function: formation, storage, and destruction of blood cells.

Question 27

pancreas

Answer 27

• produces digestive enzymes conducted to the intestinal tract through small ducts.
• secretes and releases insulin into the bloodstream to regulate glucose metabolism.