Final Organismal Biology Exam (Part I)

Front 1

Mouth

Back 1

Mouth: Amylase, enzyme responsible for starch digestion in the mouth, initiates the digestion of carbohydrates. Cells in the tongue secret lipase, which begins the digestion of lipids. Begins breaking triglycerides into fatty acids and monoglycerides. Salivary glands = water and glycoproteins called mucins.

Front 2

Esophagus

Back 2

Connects the mouth and the stomach. A wave of muscular contractions called peristalsis propels food down the esophagus. Upper third: skeletal muscle, lower third: smooth, middle third: mix of both muscles. In response to nerve signals the muscles relax or contract, it's a reflex- an automatic reaction to a stimulus.

Front 3

Ruminant stomach

Back 3

In cattle, sheep, goats, deer, antelope, giraffe, and pronghorn- species that are collectively called ruminants- the stomach is specialized for digesting cellulose-not proteins. Ruminant mammals have four chambered stomachs that are folded in complex ways

Front 4

Ruminant Stomach: Rumen

Back 4

Food initially enters the largest chamber, the rumen, which serves as a fermentation vat. The rumen is packed with symbiotic bacteria and protist. These organisms have enzymes capable of breaking apart the chemical bonds in cellulose, yielding glucose. The rumen is an oxygen-free environment, and the symbiotic organisms produce ATP from this glucose via fermentation, releasing fatty acids as by-product

Front 5

Ruminant stomach: Reticulum

Back 5

The chamber adjacent to the rumen, called the reticulum, is similar in function. After plant material has been partially digested in the rumen and the reticulum, the animal regurgitates portions of that material into its mouth, forming a cud. The ruminant chews that regurgitate material further to enhance mechanical breakdown, then re-swallows it.

Front 6

Ruminant stomach: Omasum

Back 6

Processed food that moves out of the rumen enters the third chamber, or omasum, where water is removed.

Front 7

Ruminant stomach: Abomasum

Back 7

The final chamber is the abomasum, which contains the ruminant's own digestive enzymes and corresponds to a true stomach.

Front 8

Stomach

Back 8

Physical: Muscle contractions
Chemical: The stomach produces 3 substances. 1. HCL - Strong acid that begins denaturing of proteins. It also activates the major enzyme pepsin to digest protein. In addition, it also tells salivary amylase to stop mouth digestion and kills bacteria and foodborne illness. 2. Pepsin is released to denature protein. 3. Gastric lipase enters the picture and takes over lingual lipase's job, by also minimally digesting fats.
THE RESULT OF ALL THIS IS CHYME, which then gradually moves into the s. intestine via the pyloric sphinctor. The purpose of this sphinctor is to neutralized the stomach acid befre it reaches the s. intestine.

Front 9

Small intestine

Back 9

Physical: Muscle contractions
Chemical: The s. intestine is the DIGESTION TERMINATOR. At the end, we have peptids, free AA, fatty acids, monoglycerides, glycerol, and malthose. The s. intestine does its job through many secretions. Those 5 killers or secretions are: 1. bicarbonate - which neutralized the acidic chyme to provide neutral or basic environment for other enzymes, 2. proteases-enzymes that digest proteins into smaller peptids and single AA, 3. bile-emussifies triglycerides for digestion, 4.pancreatic lipase-breaks down triglycerides into fatty acids, monoglycerides, or free glycerol, and 5. pancreatic amylase-completes the process of starch digestion all the way to maltose. IN ADDITION, brush border disaccharidases and peptidases digest disacharrides into monosacharrides and proteins into AA and few di and tripeptides.

Front 10

Gall bladder

Back 10

Bile is stored here and released in the presense of fat. In case you forgot, bile helps to emulsify fats. It is released in the small intestine and helps digestion

Front 11

Parietal, mucous, & gastric chief cells

Back 11

Parietal cells located in pits that communicate with the lumen of the stomach. Parietal cells are the source of the HCl in gastric juice.
Mucous cell, secretes the mucus that is found in gastric juice. Mucus lines the gastric epithelium and protects the stomach from by HCl.
Gastric chief cells secrete pepsinogen. Pepsinogen is converted to active pepsin by contact with the acidic environment of the stomach. Pepsin is an enzyme responsible for digesting proteins in the stomach

Front 12

Large intestine

Back 12

- Reabsorption of water and mineral ions such as sodium and chloride.
- Formation and temporary storage of feces.
- No fermentation.
- Aquaporin : protein found in large intestin, formes pores in cells to allow faster water movement, found in the kidneys, water retention of kidneys.
- Appendix: Produce and protect/store god germs for your gut. Inflamed appendix sometimes caused by faucal blockage.
absorb water from the remaining indigestible food matter and transmit the useless waste material from the body.
Helps absorb vitamins. commensal bacteria : polysaccharides -> fatty acids, flatus (gas )