rat lab Flashcards
Give the dissection process
we pinch the layer of belly skin, then make a short deep cut through the muscle layers of the anatomic wall
Then you cut up until you hit the diaphragm, where you feel some resistance
N.b that the rat has fur layer, skin layer and muscle layer,
and its important to point your scissors upwards to prevent
The mesentery
is a double layer of peritoneum, continuous with the visceral peritoneum
What are some of the obvious differences between a rat and a human
1) Gall bladder is absent in rats
2) Teeth, incisors, described as chisel shape
3)Reproductive system- uterus is Y shaped with 2 horns.
In males there is a prepuce
some shapes like the leaf shaped spleen and stuff
Some external features of rats
Rats are pentadactyl
They use their tail as a balancing organ
Nostrils can close under walter
Their vibrissae are tactile and allow the rat to navigate through confined spaces in the dark
How to identify males
prepuce,
Scrotumn
How to identify females
UVA Anterior to caudal, uva urethra vagina anus
Appearance of Lungs
CO2 poisoning
causes lungs to be dark red
and there would be hemmorhage of small blood vessels
it is usually a bright, pink colour
The stomach
mostly lies to the left
The anterior lateral has a think translucent so you can see what is visible in it
It is primarily used for food storage
The second part of the heart is medial and posterior and is glandular and opaque, being used to release acid and enzymes which break large molecules down into small ones
pyloric sphincter
Difference between human stomach and rat stomach
The human stomach does not have a glandless portion that would be covered with protective stratified, squamous epithelium
Small interstines
When you lift up the coils, you may note that they are attached to the dorsal body wall by a transparentmesentery which is actually a double layer of peritoneum
Blood vessels are associated with the mesentery
Arteries include two branches of dorsa aorta( coeliac a and superior mesenteric a), the veins draining deoxygenated, nutrient-laden blood from the wall are tributaries of the hepatic portal vein which leads to liver
Pancreas
the gland releases an alkaline juice
has endocrine and exocrine
secretes into the duodenum 1) lipase 2) amylase 3) protease and hormones like insulin
if you lift the greater curvation of the stomach, in the rat you get to lift up the stomach a look for a small pink lobules suspended in mesentery
Liver
largest exocrine and endocrine gland
1) Metabolic
2) Bile
Bile salts aid in digestion/absorption of fats/vitamins
Pacreatic ducts join the hepatic ducts into the duodenum
Hepatic artery and hepatic portal vein
Spleen
found beneath the greater curvature of the left side of the abdominal cavity
The rat one is fist shaped
the human one is leaf shaped
Caecum
bag thatcontains bacteria and shit
human ones are vermiform and contain lymphoid
Colon
1) ascending
2) transverse
3) descending
