Lab 1: Rat dissection

Question 1

what are the main differences between the rat and humans?

Answer 1

rats lack gallbladder, lack vermiform appendix( have caecum), lack canine teeth
reproductive system: female rats’ uterus is “Y” shaped with 2 “arms” or horns in which embryos implant. In males, the penis is mostly WITHIN (Not outside) the abdominal wall.

Question 2

where do absorption and secretion occur?

Answer 2

everywhere downstream of the oesophagus

Question 3

where does the esophagus enter the stomach?

Answer 3

part-way along the lesser curvature

Question 3

where does the esophagus enter the stomach?

Answer 3

part-way along the lesser curvature

Question 4

what is the position of the esophagus in relation to the heart and lungs?

Answer 4

dorsal

Question 5

what is the position of the translucent part of the rat’s stomach?

Answer 5

anterior and lateral

Question 6

what is the function of the translucent part of the rat’s stomach?

Answer 6

food storage. Its lining resembles the esophagus with no glands and a protective stratified squamous epithelium.

Question 7

does the human stomach have a transparent glandless portion like the one in the rat?

Answer 7

NO

Question 8

what is the name of the opaque region of the stomach?

Answer 8

pyloric region

Question 9

what is the position of the pyloric region?

Answer 9

medial and posterior

Question 10

what is the function of the pyloric region of the stomach?

Answer 10

has numerous tubular glands that release acid and enzymes which break large molecules down into small ones- digestion

Question 11

what is the name of the stomach outlet?

Answer 11

pyloric sphincter. A collar of smooth muscle which controls the flow of stomach contents (chyme) into the duodenum

Question 12

what is the main function of the small intestine?

Answer 12

absorption of small molecules resulting from digestion

Question 13

what are the 3 regions of the small intestine

Answer 13

DJ Ileum
Duodenum Jejunum and ileum

Question 14

what are the arteries supplying the intestinal wall with oxygenated blood?

Answer 14

2 branches of the dorsal aorta: coeliac artery and superior mesenteric artery

Question 15

what are the veins draining deoxygenated nutrient-laden blood from the wall of the small intestine?

Answer 15

tributaries of the hepatic portal vein which leads to liver( NOT directly back to the right heart as most systemic veins do)

Question 16

what is the differences and similarities between human and rat pancreas?

Answer 16

in both humans and rats, the pancreas sits close to the greater curvature of the stomach, with the pancreatic duct extending from the medial end of the gland towards the duodenum

the rat pancreas is more diffuse than the human.
the pancreas is made of small scattered pink lobules suspended by mesentery.

Question 17

what is the largest gland in the body?

Answer 17

liver

Question 18

what organs are both exocrine and endocrine( “dual purpose”)?

Answer 18

liver and pancreas

Question 19

what does bile contain?

Answer 19

mainly excretory products

Question 20

how is bile delivered to the duodenum in the rat vs human?

Answer 20

RAT: the pancreatic ducts join the hepatic duct to discharge through a common duct into the duodenum
HUMAN: bile is stored in the gallbladder whose duct( cystic duct) joins the bile duct to discharge into the duodenum

Question 21

what organ has a thin CT capsule and is very vulnerable?

Answer 21

liver
(spleen as well)

Question 22

what organs have a rich blood supply?

Answer 22

spleen, liver, kidneys

Question 23

what blood supply does the liver have?

Answer 23

dual
receives venous blood from the gut wall(via the hepatic portal vein)
also receives oxygenated blood from the aorta( via the hepatic artery, a branch of the coeliac artery)

Question 23

what blood supply does the liver have?

Answer 23

dual
receives venous blood from the gut wall(via the hepatic portal vein)
also receives oxygenated blood from the aorta( via the hepatic artery, a branch of the coeliac artery)

Question 24

what role does the pancreas play in the digestive system?

Answer 24

releases alkaline digestive juice containing enzymes( lipases, amylases, proteases) Aid digestion of proteins, fats, and carbs

Question 25

is the spleen part of the digestive system?

Answer 25

NO

Question 26

difference in the shape of the spleen in human vs rat?

Answer 26

human- more compact, fist-shaped
rat- leaf-shaped

Both sit in the same position beneath the greater curvature of the stomach on the extreme left side of the abdominal cavity

Question 27

what are the 4 parts of the large intestine?

Answer 27

caecum, colon, rectum, and anus

Question 28

the main function of the large intestine

Answer 28

reabsorption of water and formation of feces from undigested food residue. Resident bacteria contribute to the purification of this material. Faeces are retained in the rectum and voided periodically though the anus

Question 29

caecum humans vs rats

Answer 29

flabby thin-walled bag within which the brown intestinal contents are easily seen. Here bacteria act on the gut contents while they are slow-moving. The human caecum terminates in a vermiform appendix, which contains lymphoid tissue BUT RATS LACK vermiform appendix

Question 30

where are kidneys located?

Answer 30

dorsal wall of the abdominal cavity

Question 31

why are kidneys said to be “retroperitoneal”?

Answer 31

“behind the peritoneum”
the ventral surface of each kidney is covered with the parietal peritoneum, the dorsal surface is attached to the body wall.

Question 32

what is the colour of the urinary bladder?

Answer 32

pale cream or yellow

Question 33

what is the position of the nasal passages in the rat?

Answer 33

in the head dorsal

Question 34

what is the position of the trachea in the rat?

Answer 34

in the neck - ventral

Question 35

position of epiglottis relative to the glottis

Answer 35

ventral