Chapter 14 Flashcards

1
Q

How does the digestive system contribute to homeostasis?

A

Ingesting food, digesting food into nutrients that cells can use, absorbing nutrients, and eliminating indigestible remains.

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2
Q

What are the 2 processes digestion involves?

A

Mechanical and chemical digestion.

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3
Q

Describe mechanical digestion.

A

Begins with the chewing of food in the mouth, continues with the churning and mixing of food in the stomach.

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4
Q

Describe chemical digestion.

A

Enzymes break down macromolecules into smaller molecules that can be absorbed.

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5
Q

Describe the hard palate.

A

Contains several bones.

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6
Q

Describe the soft palate.

A

Made of muscle, uvula, and tonsils.

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7
Q

What do salivary glands do?

A

Produce saliva.

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8
Q

How many different glands are located in the mouth?

A

3.

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9
Q

What does saliva do?

A

Keeps the mouth moist, and contains enzyme salivary amylase which begins the process of digesting starch.

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10
Q

What do teeth do?

A

Used to chew food into pieces suitable for swallowing.

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11
Q

What is a tooth divided into?

A

Crown, root, and gingiva (gums).

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12
Q

Describe the crown of a tooth.

A

Enamel, dentin, pulp.

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13
Q

Describe the root of a tooth.

A

Dentin, pulp.

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14
Q

Describe swallowing.

A

Reflex action. Soft palate closes off the nasopharynx, trachea moves up causing the epiglottis to cover the glottis. As a result, food can enter esophagus only.

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15
Q

Describe the esophagus.

A

Muscular tube that extends from the pharynx to the stomach. Usually collapsed.

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16
Q

What is peristalsis?

A

Rhythmic muscular contractions, pushes food along digestive tract.

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17
Q

What does the sphincter muscle do?

A

Closes the esophagus from the stomach. Relaxation of the sphincter allows food to enter the stomach.

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18
Q

What are the 4 layers of the digestive tract?

A

Mucosa, submucosa, muscularis, and serosa.

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19
Q

Describe mucosa.

A

Glandular epithelial cells secrete enzymes. Goblet cells secrete mucus.

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20
Q

Describe submucosa.

A

Loose connective tissue that contains blood vessels. Peyer’s patches-lymph nodules.

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21
Q

Describe muscularis.

A

Two layers of smooth muscle, circular: inner layer encircles tube, and longitudinal: outer layer runs perpendicular.

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22
Q

Describe serosa.

A

Secretes serous fluid to moisten surface so that organs can slide against each other.

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23
Q

Describe the stomach.

A

Thick-walled, J-shaped organ. Continuous with esophagus and duodenum of small intestine. Receives food from the esophagus, starts the digestion of proteins, and moves food into the small intestine.

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24
Q

What lines the stomach?

A

The columnar epithelium which contains gastric pits which lead into gastric glands.

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25
Q

What do gastric glands produce?

A

Gastric juice.

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26
Q

What does hydrochloric acid do in the stomach?

A

Lowers pH to make optimum environment for enzymes.

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27
Q

What is pepsinogen?

A

Becomes pepsin when mixed with HCl, then breaks down proteins.

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28
Q

What is mucus needed for?

A

To move food along.

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29
Q

Which ways does the stomach act on food?

A

Mechanically and chemically. Has 3 layers of muscles. Churns food and mixes it with gastric juice.

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30
Q

Is most food absorbed by the stomach?

A

No. Alcohol and other lipids are.

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31
Q

What is chyme?

A

Food leaving the substance. Enters small intestine through pyloric sphincter.

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32
Q

Describe the small intestine.

A

Smaller in diameter compared to large intestine.

33
Q

What is the duodenum?

A

The first 25 cm of the small intestine. Receives bile from the liver.

34
Q

What does bile do?

A

emulsifies fats.

35
Q

What does the duodenum do?

A

Receives pancreatic juice from the pancreas. Many enzymes for digestion of nutrients. Bicarbonate to neutralize acidic pH of chyme.

36
Q

What are other parts of the small intestine?

A

Jejunum: middle section.
Ileum: remainder leading to large intestine, contains peyer’s patches-immune response to intestinal pathogens.

37
Q

What are villi?

A

Finger-like projections. carries sugars and amino acids.

38
Q

What are lacteals?

A

Inside villi- lymph capillary. Interacts with nearby blood capillaries at site. Carries digested fats.

39
Q

What are microvilli?

A

Microscopic extensions on surface of epithelial cells of villi. Many small areas of absorption.

40
Q

How are digestive secretions regulated?

A

By the nervous system and by hormones.

41
Q

What is a hormone?

A

Substance produced by a group of cells that affects a different group of cells.

42
Q

What are the two other hormones that regulate digestion?

A

Secretin, and CCK.

43
Q

Describe secretin.

A

Produced by duodenal wall. Release stimulated by entrance of HCl in chyme. Then stimulates bicarbonate production in pancreas to take out H+. Stimulate bile production in liver.

44
Q

Describe CCK.

A

Produced by duodenal wall. Release stimulated by proteins and fat in chyme. Stimulates gall bladder to release bile in order to deal with fats.

45
Q

What do secretin and CCK act on?

A

Three organs: pancreas to increase pancreatic juice output.
Liver to increase bile output.
Gallbladder to contract to release bile.

46
Q

Describe the large intestine.

A

Includes cecum, colon, rectum, and anal canal. Larger in diameter than small intestine but shorter in length.

47
Q

What are the functions of the large intestine?

A

Absorbs water, salts, and some vitamins. Stores indigestible materials until eliminated as feces.

48
Q

What is the cecum?

A

Lies below junction with small intestine. Small pouch that forms first part of the large intestine.

49
Q

Where is the appendix?

A

Projection on the cecum.

50
Q

What does the appendix do?

A

Role in fighting infection, but subject to inflammation.

51
Q

Describe the colon.

A

Part of large intestine. Ascends, transverse, and descends.

52
Q

Describe the rectum.

A

Last 20 cm of large intestine. Opens to anus.

53
Q

Describe the anus.

A

Where defecation occurs. Reflex triggered as feces is forced into the rectum.

54
Q

What is feces?

A

Typically 3/4 water and 1/4 solids. Bacteria, plant fiber, and indigestible materials are in the solid portion.

55
Q

What is bilirubin?

A

Brown colour of feces comes from this. Is from broken down and aged red blood cells.

56
Q

What are the accessory organs of digestion?

A

Pancreas, liver, gallbladder, 3 salivary gland types.

57
Q

Describe the pancreas.

A

Endocrine function. Insulin promotes absorption of glucose from blood to fat, liver, and skeletal muscle cells. Absorbed glucose becomes glucagon in these cells. Insulin helps with protein synthesis in some cells. Control release of glucose from liver and other cells.

58
Q

What does gastric juice contain?

A

Sodium bicarbonate: neutralizes the stomach acid.
Pancreatic amylase: digests starch.
Trypsin: digests protein.
Lipase: digests fats.

59
Q

Describe the liver.

A

Largest gland in the body. Lobules are structural and functional units.

60
Q

What does the liver do?

A

Acts as a gatekeeper for the blood. Detoxifies and removes poisonous substances. Removes and stores iron and vitamins. Makes plasma proteins. Regulates cholesterol. Regulates blood glucose. Produces bile.

61
Q

Describe the gallbladder.

A

Gallbladder stores excess bile. Water is reabsorbed so that bile is thickened. Bile is secreted through the common bile duct into the duodenum.

62
Q

What are some proteins that speed up specific chemical reactions?

A

Carbohydrates, proteins, nucleic acids, and fats.

63
Q

Describe salivary amylase.

A

Starch to maltose in the mouth.

64
Q

Describe pepsin.

A

Proteins to peptides in the stomach.

65
Q

What is pancreatic juice pH?

A

Basic to neutralize acidic stomach chyme. and optimum for enzymes.

66
Q

What is lipase?

A

A third pancreatic enzyme, digests fats.

67
Q

What also produces enzymes?

A

Small intestine villi cells.

68
Q

What enzymes do small intestine villi cells produce?

A

Peptidases: peptides to amino acids
Maltase: maltose sugar to glucose.

69
Q

What is nutrition?

A

The intake of nutrients.

70
Q

What is a nutrient?

A

A component of food utilized by the body as it performs physiological function.

71
Q

What does water have to do with nutrients?

A

All bio-chemical reactions occur in water. Fills spaces between cells. Essential for digestion and excretion.

72
Q

What do vitamins have to do with nutrients?

A

Organic compound needed in limited amounts. Help with numerous bio-chemical reactions.

73
Q

What do minerals have to do with nutrients?

A

Inorganic nutrients. Support bio-chemical processes as well as electrolytes for nervous system.

74
Q

What is diet?

A

Made up of the food choices that fulfill nutrient needs.

75
Q

What are some factors contributing to obesity?

A

Sedentary life style, processed foods, higher number of fat cells in obese individuals, and reduced levels of leptin- the hormone that inhibits hunger.

76
Q

Describe complex carbohydrates.

A

Recommended. Slowly digested to sugars. Also contain fiber, insoluble fiber: undigestible plant material. Soluble fiber: fiber derived from peas, beans, nuts, fruits, and vegetables.

77
Q

Describe cholesterol

A

Waxy, fat like substance found in all of our cells. Makes cells resistant to water soluble molecules; helps cell membrane maintain proper firmness. Helps make hormones and vitamin D and help make bile salts for digestion.

78
Q

What is LDL?

A

Low density lipoprotein. Bad cholesterol. Transports cholesterol from the liver to cells. Can cause fatty buildup in arteries or plaque.

79
Q

What is HDL?

A

High density lipoprotein. transports cholesterol to the liver. Liver can then use to make bile salts. Liver can also get rid of excess cholesterol.