Rat Dissection Lab

What is unique about rat incisors?

they grow continuously throughout life

Why do rat incisors remain sharp?

no enamel on the posterior surface

What shape are rat incisors?

chisel shaped for gnawing

Do rats have canines?

no

Do rats have a gall bladder?

no

Where does bile go in rats?

directly from liver to the duodenum

What does the human gall bladder do?

stores and concentrates bile

Describe the female rat uterus.

y shaped with two uterine horns

Why is the rat uterus Y-shaped?

allows multiple embryos to develop during pregnancy

Where is the rat penis located?

mostly inside abdominal wall

What covers the rat penis?

prepuce

What is the function of a rat's tail?

balance

What happens to the human embryonic tail?

disappears before birth

Where is the male rat scrotum located?

close to the anus

Where are the testes located?

inside scrotum

Is the rat penis mostly internal or external?

internal

How many external openings does a female rat have?

three

Name the three openings in a female rat.

urethral, vaginal, anus

Do both male and female rats have nipples?

yes

What organs are found in the thoracic cavity?

heart and lungs

What separates the thoracic cavity from the abdominal cavity?

diaphragm

What organs are found in the abdominal cavity?

stomach, liver, pancreas, small intestine, large intestine, spleen, kidneys

Name the four ventral body cavities.

right pleural cavity, left pleural cavity, pericardial cavity, peritoneal cavity

What is a serous membrane?

thin membrane that lines body cavities and covers organs.

What cells form serous membranes?

mesothelial cells

What do serous membranes secrete?

serous fluid

What is the function of serous fluid?

reduce friction between organs

What is the peritoneum?

serous membrane lining the abdominal cavity

What is the parietal peritoneum?

lines the abdominal wall

What is the visceral peritoneum?

covers abdominal organs

What is the mesentery?

double layer of peritoneum

What are the functions of the mesentery?

suspends intestines, carries blood vessels, nerves and lymphatics

What is the pleura?

membrane surrounding the lungs

What is the parietal pleura?

lines the thoracic wall

What is the visceral pleura?

covers the lung surface

What is the pericardium?

membrane surrounding the heart

What is found inside the pericardial cavity?

heart and small amount of lubricating fluid

What do healthy lungs look like?

bright pink and spongy

hy are lab rat lungs dark red?

filled with blood due to co2 euthanasia

Where is the thymus located?

over anterior surface of heart

What type of organ is the thymus?

lymphoid organ

What are the functions of the thymus?

produce hormones, mature t lymphocytes

List the digestive tract in order.

mouth, pharynx, oesophagus, stomach, duodenum, jejunum, ileum, caecum, colon, rectum, anus

What is the food pathway?

mouth, pharynx, oesophagus

What is the air pathway?

nose, pharynx, oesophagus

What is the hard palate?

bony roof separating mouth from nasal cavity

What is the soft palate?

posterior part of the palate with no bone

What is the glottis?

opening of trachea

What is the epiglottis?

small flap above glottis

What happens to the epiglottis during swallowing?

closes over the glottis to stop food entering the trachea

What happens to the epiglottis during breathing?

remains open

Is the oesophagus dorsal or ventral to the trachea?

dorsal

What does the oesophagus carry?

food to stomach

What does the oesophagus pass through before reaching the stomach?

diaphragm

Where is the rat stomach located?

mostly left side

What are the two stomach regions?

transparent and opaque

What is the function of the transparent stomach?

food storage

What epithelium lines the transparent stomach?

stratified squamous epithelium

Does the transparent stomach contain glands?

no

What is the function of the opaque stomach?

chemical digestion

What does the opaque stomach produce?

acid, digestive enzymes, pancreatic juice

Where does most stomach digestion occur?

opaque area

What is chyme?

partially digested food

What does the pyloric sphincter do?

controls movement of chyme into the duodenum

What is the main function of the small intestine?

absorb nutrients

Name the three regions of the small intestine

duodenum, jejunum, ileum

What attaches the small intestine to the body wall?

mesentery

Which arteries supply the small intestine?

coeliac artery, superior mesenteric artery

Which vein drains nutrient-rich blood from the gut?

hepatic portal vein

Where does blood from the hepatic portal vein go?

liver

What are the exocrine functions of the pancreas?

produce digestive enzymes

Name three pancreatic digestive enzymes.

lipase, amylase, protease

Where are pancreatic digestive enzymes released?

duodenum

What is the endocrine function of the pancreas?

produce hormones

Name the main pancreatic hormone.

insulin

Where are pancreatic hormones released?

bloodstream

What is the largest gland in the body?

liver

List four liver functions.

produces bile, metabolism, detoxification, nutrient storage

What is the function of bile?

emulsify fats

Is the spleen part of the digestive system?

no, part of lymphatic system

Describe the spleen.

dark red, leaf-shaped, left side beneath stomach

Functions of the spleen?

immune response, blood filtration

Name the parts of the large intestine.

caecum, colon, rectum, anus

Main functions of the large intestine?

water reabsorption, faeces formation

What is the caecum?

large thin-walled sac

Function of the caecum?

bacterial fermentation, breaks down cellulose

What is a major difference between humans and rats regarding the caecum?

humans have an appendix, rats do not

Function of the colon?

water reabsorption, forms firmer faeces

Function of the rectum?

stores faeces before defecation

What surrounds the anus?

anal sphincter

Is the anal sphincter under voluntary control?

partially

Functions of the kidneys?

filter blood, produce urine

Where are the kidneys located?

dorsal abdominal wall

What does retroperitoneal mean?

covered only anteriorly by peritoneum.

What is the hilus?

entry and exit point of the kidney

Where are the adrenal glands located?

above the kidneys

What does the adrenal cortex produce?

steroid hormones