Download Human Anatomy and Physiology

Human Anatomy and Physiology
Name:
Date:
Study Guide for Digestion and Nutrition
1. What is digestion?
a. Mechanical and chemical breakdown of foods into nutrients that cell membranes can
absorb
2. Name all of the major components of the digestive system, including all accessory organs.
a. Alimentary canal: mouth, pharynx, esophagus, stomach, small intestine, large intestine
and anal canal; accessory: salivary glands, liver, gallbladder, pancreas
3. What are the four layers of the walls of the alimentary canal? Give specifics.
a. Mucosa
i. Surface epithelium, underlying connective tissue, small amount of smooth muscle
ii. Folds or projections extend into passageway (lumen)
iii. Glands that are tubular invaginations into which lining cells secrete mucus and
digestive enzymes
iv. Secretes, absorbs, protects the tissues beneath it
b. Submucosa
i. Considerable loose connective tissue
ii. Glands, blood vessels, nerves = network called plexus
iii. Nourishes and carries away absorbed materials
c. Muscular layer
i. Two coats of smooth muscle tissue and plexus
ii. Circular fibers (inner)
iii. Longitudinal fibers (outer)
d. Serosa
i. Visceral peritoneum (outer covering of tube)
ii. Protects underlying tissues
iii. Secretes serous fluid to moisten and lubricate out surface so canal slides freely
against the organs of the abdominal cavity
4. How does peristalsis occur? Draw a series of diagrams and describe the motions.
Wavelike motion: a ring of contraction appears in the wall of the tube; wall ahead of ring
relaxes; peristaltic wave moves along and pushes the contents of the tube ahead of it
5. Where does mechanical digestion occur? How?
a. Mechanical digestion begins with mastication in the mouth, which reduces the size of
solid particles and mixes them with saliva, and continues in the stomach with mixing
movements (waves of muscular contractions that move along its walls from one end to
another)
6. What are the three types of salivary glands and where are they located? What are the contents of
their secretions and what do they do?
a. Parotid
i. Lies in front of and somewhat below each ear, between skin of cheek and
masseter muscle
ii. Secretes serous fluid, rich in amylase
b. Submandibular
i. In floor of mouth on inside surface of lower jaw
1. Mostly serous, a few mucous cells that make fluid more viscous than
parotid secretions
c. Sublingual
i. Smallest of major salivary glands, on floor of mouth under tongue
1. Secretions mostly mucous type (thick and stringy)
7. What are the physical features of the esophagus? (length, location, sphincters)
a. Straight, collapsible tube, 25 cm long
b. Connects pharynx to stomach
c. Goes through diaphragm through the esophageal hiatus
d. Lower esophageal sphincter (cardiac sphincter) joins esophagus to stomach
8. How does peristaltic action occur in the esophagus?
a. See above
9. What are the physical features of the stomach? (size, components, sphincters)
a. Shaped like a “J”
b. Capacity of 1 liter+
c. Rugae are folds of mucosal and submucosal layers
d. Regios are fundic, cardiac, body, pyloric
e. Pyloric sphincter: controls gastric emptying of stomach contents into duodenum (entrance
of small intestine)
10. What are the gastric secretions of the stomach?
a. Pepsinogen
i. Secreted by chief cells as precursor to pepsin
b. Pepsin
i. Formed from pepsinogen in the presence of hydrochloric acid
ii. Digests nearly all types of protein
c. HCl
i. Secreted by parietal cells of gastric glands
d. Mucus
i. Goblet cells and mucous glands
ii. Provides an alkaline protective layer on inside of stomach wall
e. Intrinsic factor
i. Secreted by parietal cells of the gastric glands
ii. Aids in vitamin B12 absorption
11. What are the three types of cells in the stomach lining and what does each secrete?
a. Gastric pits are lined with the following types of cells
i. Goblet (mucous)
ii. Parietal (HCl; intrinsic factor)
iii. Chief (pepsinogen)
12. What mechanisms does the stomach use to protect itself?
a. Mucous cells secrete mucus and alkaline secretion to neutralize acid at the stomach wall
b. Prevents pepsin from digesting the proteins in the stomach lining itself
13. What hormones are involved in the production of stomach secretions?
a. Acetylcholine is released when food enters stomach
b. Stomach cells are stimulate to release gastrin (a hormone), which increases the secretory
activity of the gastric glands
c. Cholecystokinin (peptide hormone) is released when fats and proteins enter the small
intestine, which decreases gastric motility as small intestine fills with food
14. What does the stomach absorb?
a. Small quantities of
i. Water and certain salts
ii. Alcohol
iii. Some lipid-soluble drugs
15. What is chyme?
a. Semifluid paste of food particles and gastric juice (product of the mixing movements of
the stomach)
16. What is the structure and location of the pancreas?
a. Extends horizontally across the posterior abdomen wall in the C-shaped curve of the
duodenum
b. Made of pancreatic acinar cells which lead to pancreatic duct along its length
c. Pancreatic duct connects to duodenum when bile duct from liver and gallbladder connects
d. Hepatopancreatic sphincter controls movement of pancreatic juices into duodenum
17. What are the two types of functions of the pancreas?
a. Endocrine: insulin and glucagons
b. Exocrine: secretion of pancreatic juice
18. List the enzymes contained in pancreatic juice and explain what each enzyme does.
a. Pancreatic amylase
i. Splits starch into disaccharides
b. Pancreatic lipase
i. Breaks triglyceride molecules into fatty acids and glycerol
c. Nucleases
i. Break nucleic acids into nucleotides
d. Proteolytic enzymes: break bonds between particular amino acids in proteins; stored in
zymogen granules in inactive forms; pancreatic cells release inactive trypsinogen
i. Trypsin
ii. Chymotrypsin
iii. Carboxypeptidase
e. Enterokinase: secreted by the mucosa of the small intestine
i. Enzyme that activates trypsinogen to become trypsin
19. How are secretions of the pancreas regulated?
a. Secretin (peptide hormone) is released into the bloodstream as acidic chyme enters the
duodenum
b. Stimulates the secretion of pancreatic juice high in bicarbonate ions (to neutralize chyme
and provide favorable environment for digestive enzymes in the intestine)
20. Where is the liver located?
a. Upper right quadrant of the abdominal cavity, just below the diaphragm
21. Describe the structure of the liver.
a. Enclosed by a fibrous capsule
b. Divided into right and left lobes by connective tissue
c. Each lobe is separated into smaller hepatic lobules (functional units of liver)
d. One lobule = many hepatic cells radiating outward from a central vein
e. Hepatic sinusoids separate groups of hepatic cells from one another
f. Kuppfer cells remove bacteria and other foreign particles
g. Bile canals are in hepatic lobules and converge to become hepatic ducts
h. Hepatic ducts merge to become the common hepatic duct
22. What is the relationship of blood vessels to liver function? Explain, using a diagram.
a. Blood from the digestive tract (carried by portal vein) brings newly absorbed nutrients
into the sinusoids and nourishes hepatic cells
23. What are all the functions of the liver?
a. Carbohydrate metabolism
i. Polymerizes glucose to glycogen
ii. Breaks down glycogen to glucose
iii. Changes noncarbohydrates to glucose
b. Lipid metabolism
i. Oxidizes fatty acids
ii. Synthesizes lipoproteins, phospholipids and cholesterol
iii. Changes portions of carbohydrate and protein molecules into fats
c. Protein metabolism
i. Deaminates amino acids
ii. Forms urea
iii. Synthesizes plasma proteins
iv. Changes certain amino acids to other amino acids
d. Storage
i. Stores glycogen, iron and vitamins A, D and B12
e. Blood filtering
i. Removes damaged red blood cells and foreign substances by phagocytosis
f. Detoxification
i. Removes toxins from blood
g. Secretion
i. Secretes bile, which enters duodenum when cholecystikinin stimulate gall bladder
to contract
ii. Bile is a yellowish green liquid which contains:
1. bile salts: emulsification of fat globules, which increases surface area and
allows lipases to work more effectively
2. bile pigments: bilirubin and biliverdin (products of r.b.c. breakdown)
3. cholesterol
4. electrolytes
24. What is the structure and location of the gall bladder? Explain its function and the function of
bile salts.
a. Pear-shaped sac in a depression on the inferior surface of the liver
b. Connects to the cystic duct, which joins the hepatic duct
c. Lined with epithelial tissue; strong, muscular layer in its wall
d. Stores bile between meals
e. Reabsorbs water to concentrate bile
f. Releases bile into small intestine
25. What is the structure and function of the small intestine?
a. Duodenum
b. Jejunum
c. Ileum
d. Intestinal villi: greatly increase surface area for absorption
e. Intestinal glands: lie at the base of villi
26. What enzymes are produced by the small intestine and what do they break down?
a. Peptidases
i. Split peptides into amino acids
b. Sucrase, maltase, lactase
i. Split disaccharides into glucose, fructose and galactose
c. Intestinal lipase
i. Splits fats into fatty acids and glycerol
27. How are secretions regulated in the small intestine?
a. Goblet cells and intestinal glands secrete products upon presence of chyme
28. How does absorption occur in the small intestine?
a. Villi absorb glucose, which enters blood capillaries
i. Active transport or facilitated diffusion
ii. Amino acids are actively transported into the villi and carried away by the blood
iii. Fatty acids and glycerol diffuse into villi epithelial cells; brought to lacteals as
chylomicrons, then to blood stream
iv. Short carbon chained fatty acids are absorbed directly into blood capillary of a
villus without being changed back into fat
29. What is the shape and function of the large intestine?
a. Cecum, colon, rectum, anal canal
b. No villi
c. Distinct bands of longitudinal muscle fibers
d. Mucus binds fecal matter
e. Alkalinity controls pH of large intestine contents
f. Absorbs water and electrolytes
g. Mass movements
h. Defecation reflex
30. What is nutrition?
a. Process by which the body takes in and utilizes food substances
31. Name some sources of carbohydrates and explain how they are used.
a. Organic compounds used primarily to supply energy for cellular processes
b. Starch from grains and vegetables
c. Glycogen from meats
d. Disaccharides from cane sugar, beet sugar, molasses
e. Monosaccharides from honey and fruits
f. Fructose, galactose and glucose are absorbed from digestive tract
g. Liver enzymes turn fructose and galactose to glucose, most common cellular fuel
32. What are the requirements for carbohydrates?
a. 125-175 grams of carbohydrates is necessary per day to avoid protein breakdown and to
avoid metabolic disorders from excess fat utilization
33. What are some sources of lipids?
a. Triglycerides from plant and animal based foods
i. Saturated fats
1. Meats
2. Eggs
3. Milk
4. Lard
ii. Unsaturated fats
1. Seeds
2. Nuts
3. Corn oil
4. Peanut oil
5. Olive oil
iii. Cholesterol
1. Liver
2. Egg yolk
3. Whole milk, butter, cheese, meats
34. How does the body utilize lipids?
a. Liver and adipose tissue control lipid metabolism
i. Liver synthesizes triglycerides, phospholipids, lipoproteins
ii. Controls level of cholesterol in the body
35. What are the requirements for lipids in the body?
a. Structural
b. Energy source
36. What are some sources of proteins?
a. Meats
b. Fish
c. Poultry
d. Cheese
e. Nuts
f. Milk
g. Eggs
h. Cereal
i. Legumes (beans and some peas)
37. What are the requirements for proteins in the body?
a. Enzymes to control metabolic rates
b. Clotting factors
c. Keratin of skin and hair
d. Elastin and collagen of connective tissue
e. Plasma proteins that regulate water balance
f. Muscle components actin and myosin
g. Certain hormones
h. Antibodies
i. Amino acids are potential sources of energy
i. Essential amino acids cannot be made by the body (8 or 20 in adults)
38. What are vitamins? Give some examples of both types.
a. Vitamins are organic compounds required in small amounts for normal metabolic
processes, but which body cells cannot synthesize in adequate amounts
b. Essential nutrients that food must supply
c. Fat soluble
i. Vitamin A
ii. Vitamin D
iii. Vitamin E
iv. Vitamin K
d. Water soluble
i. B vitamins
ii. Vitamin C (ascorbic acid)
39. What are the characteristics of minerals? Name some major minerals.
a. Minerals are elements other than carbon that are essential in human metabolism
b. Calcium
c. Phosphorus
d. Potassium
e. Sulfur
f. Sodium
g. Chlorine
h. Magnesium
40. What are some trace elements?
a. Iron
b. Manganese
c. Copper
d. Iodine
e. Cobalt
f. Zinc
g. Fluorine
h. Selenium
i. Chromium