Comparative Anatomy

Procuring and manipulating food (cut and pierce) vs. processing of the food (grind and shear).

Incisors (I): Canines (C): Premolars (P): Molars (M)Teeth in upper jaw/teeth in lower jaw. Only one half of the jaw.

Temporalis: moves the jaw up and down necessary for biting.Masseter and pterygoideus: move the jaw from side to side and are important in mastication

Teeth that are covered in ridges in order to grind vegetation.

Fermentation occurs in the rumen and reticulum, which both absorb the main products of bacterial fermenation. Omasum separates and absorbs water from the food.Abomasum secretes the acid that kills microorganisms and begins the process of protein digestion. An example is a deer.

Long small intestine and colon, caecum present vs. relatively short intestines, small or absent caecum.

Consists of the alimentary canal, salivary glands, pancreas, liver and gall bladder. It is concerned with the breakdown of ingested food and its absorption into the bloodstream.

Mouth: food masticated, salivary amylase secreted, bolus_passes down pharynx into oesophagus_peristalsis moves food into stomach_gastric glands secrete enzymes, water and HCl_chyme passes through pyloric sphincter into S.I._digestion in duodenum, absorption in jejunum and ileum_L.I. helps reclaim more than 90% of water_faeces passed through rectum and anus.

Dogfish three liver lobes, a gall bladder, short segment of intestine and a long, leaf-like spleen.Frog three liver lobes, a gall bladder, relatively long intestine and a small, round, red spleen.Rat four liver lobes, no gall bladder, long intestine and an oblong, c-shaped, maroon spleen.

Kidneys and their ducts; paired testes or ovaries and their associated ducts.

Testes are abdominal, except in mammals where they are scrotal. Ovaries are always abdominal, served by the oviducts. Cloaca common chamber into which the kidney, intestinal and sometimes genital products are passed.

Dogfish one, brown, elongate kidney, no bladder.Frog two long, flat kidneys, and a bi-lobed bladder. Ureters open into the cloaca, urine is then forced into the bladder where it is stored.Rat two, kidney bean shaped kidneys, one small sac-like bladder.

Only the right ovary is present. The oviducts are large tubes suspended in the mesotubaria. Fertilization takes place in the upper oviduct. The zygote passes into the shell gland, which secretes a tough heavy capsule about the zygote. Oviduct narrows and proceeds to the cloaca.

Testes attached by the mesochium, coiled vas deferens that straigtens and dilates near the cloaca to form the seminal vesicle which leads through the urinogenital sinus.

The ovaries are black and white masses, the oviducts are translucent, coiled tubes that open at the base of the lung. Before opening into the cloaca, the oviduct swells into the egg sac.