Digestion, Absorption, And Transport

Front 1

Identify the physical and chemical aspects of digestion that takes place at each of the folowing sites along the digestive tract: MOUTH

Back 1

Physical: Chewing
Chemical(4): 1. The fluid portion of the saliva moistens the food. 2. The mucus that is produced helps to protect GI lining. 3. Lysozyme helps kill bacteria. 4. The salivary glands secrete enzymes (2). The first one is salivary amylase which starts starch digestion. The second enzyme is lingual lipase, which begins fat digestion, but not significantly.

Front 2

Identify the physical and chemical aspects of digestion that takes place at each of the folowing sites along the digestive tract: ESOPHAGUS

Back 2

Physical: After the food is chewed up and becomes bolus, it is swallowed into the esophagus. Entry into the stomach is controlled by the esophageal sphincter, that relaxed to move food, but quickly contracts to prevent upward flow of acid. This happens via muscle contractions.
Chemical: None

Front 3

Identify the physical and chemical aspects of digestion that takes place at each of the folowing sites along the digestive tract: STOMACH

Back 3

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 4

Identify the physical and chemical aspects of digestion that takes place at each of the folowing sites along the digestive tract: SMALL INTESTINE

Back 4

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 5

Identify the physical and chemical aspects of digestion that takes place at each of the folowing sites along the digestive tract: LARGE INTESTINE

Back 5

Look in book.

Front 6

What is peristalsis?

Back 6

This is muscle movement that causes wave-like contractions to move food. It also helps mix food with secretions of the Gi tract.

Front 7

What is segmentation?

Back 7

Like peristalsis, segmentations are muscle contractions that not only mix food with secretions and movies it, it also tears the food apart.

Front 8

What are sphincters and where are they located?

Back 8

Sphinctors are collections of muscle that prevent the contents of one organ from carrying over to another. Ex: esophageal and pyloric

Front 9

List four mechanisms by which nutrients are absorbed. How are these mechanisms different?

Back 9

1. Diffusion - simple movement acors area of h. concentration to l. concentration to balance it out
2. Faciliated Diffusion-same process, but this one requires a carrier molecule
3. Active Transport-requires not only a carrier, but also an input of energy
4. Endocytosis-the cell engulfes, or drinks, the sbstance and brings in it. This is done by the membrane.

Front 10

How does the structure of the small intestine aid in absorption?

Back 10

Additional cells produced by epitheial cells, called villi and microvilli assist in this process. They have a tremondous surface area. Look in book.

Front 11

Also important to the function of the Gi tract, describe how each of the following organs participates in the digestive process: SALIVARY GLANDS

Back 11

Look in book.

Front 12

Describe how each of the following organs participates in the digestive process: LIVER

Back 12

It synthesizes bile.

Front 13

Describe how each of the following organs participates in the digestive process: GALLBLADDER

Back 13

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

Front 14

Describe how each of the following organs participates in the digestive process: BILE DUCT

Back 14

This connects the gallbladder to the s. intestine along with the pancreas.

Front 15

Describe how each of the following organs participates in the digestive process: PANCREAS

Back 15

This organ releases bicarbonate and digestive enzymes.

Front 16

What are villi and microvilli?

Back 16

Villi are small projections all along the surface of the s. intestine and aid in absorption by increasing the surface area. Microvilli, located on the villi or the epitheial cells, are classified as brush-border absorptions. The other B-B enzymes come here.

Front 17

What is a lacteal?

Back 17

Look in book.

Front 18

What products of digestion are transported by the lymphatic system?

Back 18

One of the two circulatory systems, the lymphatic system initial carries fat-soluble nutrients(which are the resisting fats). The nutrients go from lacteal in intestinal villi to lymphatic system which then merges with blood steam at juglar vein. By this time, the nutrients are part of the general blood circulation.

Front 19

What products are directly absorbed into the blood?

Back 19

After absorption, the blood stream, one of the two circulatory systems, picks up the water-soluble nutrients where they are taken to the intestinal capillaries, then the portal vein, and evetually to the liver to be stored.

Front 20

Identify potential problems along the digestive tract and possible diet-related solutions.

Back 20

There are many problems.
1. Heartburn - Tx is eating smaller meals, avoid lying down
2. Gas - Occurs when we swallow air or chewing gum, eating too fast, or a product of bacterial digestion of fiber and other indigestibles
3. Ulcers-occur on duodenum or pyloric sphinctor that is caused by helicobactger pylori bacteria, chronic use of anti-inflammatory medication. Tx-is mainly meds and avoiding foods that cause pain because they will irritate to sores(ulcers).
4. Constipation-refers to difficult and infrequent defecatin of hard dry stool that are hard to move along l. intestine. Tx is increasing fiber and water inake along w/ exercise
5. Diarrhea-the opposite of constipation, this is the frequent release of loose stools. It's usually a sympton of other problem. Tx-is resolving the illness and replacing the electrolyes and fluid