Lecture 22 Flashcards

1
Q

Large intestine: Smooth muscle =

A

mechanical digestion

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2
Q

Mechanical: Peristaltic waves:

A

haustral churning
gastroilial reflex
gastrocolic reflex

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3
Q

haustral churning-

A

relaxed pouches are filled from below by muscular contractions

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4
Q

gastroilial reflex =

A

when stomach is full, gastrin hormone relaxes ileocecal sphincter so small intestine will empty and make room

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5
Q

gastrocolic reflex =

A

when stomach fills, a strong peristaltic wave moves contents of transverse colon into rectum

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6
Q

Chemical Digestion in Large Intestine:

A
  1. No enzymes are secreted only mucous
  2. Bacteria ferment
  3. Bacteria produce vitamin K and B in colon
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7
Q

Bacteria ferment: 1st step

A
  1. undigested carbohydrates into carbon dioxide & methane gas
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8
Q

Bacteria ferment: 2nd step

A
  1. undigested proteins into simpler substances (indoles)—-odor
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9
Q

Bacteria ferment: 3rd step

A
  1. turn bilirubin into simpler substances that produce color
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10
Q

Absorption in the Large Intestine:

A
  1. Some electrolytes—Na+ and Cl-

2. After 3 to 10 hours, 90% of H2O has been removed from chyme

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11
Q

Feces are

A

semisolid by time reaches transverse colon

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12
Q

Feces =

A

dead epithelial cells, undigested food such as cellulose, bacteria

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13
Q

Defecation: What moves feces into the rectum?

A

Gastrocolic reflex

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14
Q

Defecation: What signals the sacral spinal cord?

A

stretch receptors

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15
Q

Defecation: What contracts muscles of the rectum and relax the internal anal sphincter?

A

parasympathetic nerves

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16
Q

Defecation: What is voluntarily controlled?

A

external sphincter

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17
Q

Diarrhea =

A

chyme passes too quickly through intestine

H2O not absorbed

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18
Q

Constipation–

A

decreased intestinal motility

too much water reabsorbed

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19
Q

Dietary fiber- Insoluble fiber:

A
  • woody parts of plants

- speeds up transit time & reduces colon cancer

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20
Q

Dietary fiber- Soluble fiber:

A
  • gel-like consistency = beans, oats, citrus white parts, apples
  • lowers blood cholesterol
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21
Q

How does soluble fiber lower blood cholesterol?

A

by preventing reabsorption of bile salts so liver has to use cholesterol to make more

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22
Q

Functions of food:

A

source of energy
essential nutrients
stored for future use

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23
Q

Metabolism is

A

all the chemical reactions of the body

24
Q

Absorptive state:

A
  1. nutrients entering the bloodstream
  2. glucose readily available for ATP production
  3. 4 hours for absorption of each meal
25
Q

Postabsorptive state:

A
  1. absorption of nutrients from GI tract is complete
  2. body must meet its needs without outside nutrients
  3. maintaining a steady blood glucose level is critical
26
Q

Body cells use glucose for

A

ATP production

27
Q

Storage of excess fuels occur in

A

hepatocytes, adipocytes & skeletal muscle

28
Q

most glucose entering liver cells is converted to

A

glycogen (10%) or triglycerides (40%)

29
Q

dietary lipids are stored in

A

adipose tissue

30
Q

amino acids are

A

deaminated to enter Krebs cycle or are converted to glucose or fatty acids

31
Q

amino acids not taken up by

A

hepatocytes used by other cells for synthesis of proteins

32
Q

Beta cells of pancreas release

A

insulin

33
Q

Insulin’s functions:

A
  1. increases anabolism & synthesis of storage molecules
  2. decreases catabolic
  3. promotes entry of glucose & amino acids into cells
  4. stimulates phosphorylation of glucose
  5. enhances synthesis of triglycerides
  6. stimulates protein synthesis along with thyroid & growth hormone
34
Q

Maintaining normal blood glucose level

A

(70 to 110 mg/100 ml of blood) is major challenge

35
Q

glucose enters blood from 3 major sources:

A
  1. glycogen breakdown in liver produces glucose
  2. glycerol from adipose converted by liver into glucose
  3. gluconeogenesis using amino acids produces glucose
36
Q

alternative fuel sources are

A
  1. fatty acids
  2. lactic acid
  3. oxidation of ketone bodies by heart & kidney
37
Q

Most body tissue switch to

A

utilizing fatty acids, except brain still need glucose

38
Q

As blood glucose level declines

A

pancreatic alpha cells release glucagon

39
Q

glucagon stimulates

A

gluconeogenesis & glycogenolysis within the liver

40
Q

Hypothalamus detects

A

low blood sugar

41
Q

sympathetic neurons release

A

norepinephrine

42
Q

adrenal medulla releases

A

norepinephrine & epinephrine

43
Q

determining factor of starvation;

A

amount of adipose tissue

44
Q

Nutritional needs:

A
  1. nervous tissue & RBC need glucose

2. increase in formation of ketone bodies by liver cells

45
Q

Catabolic reactions breakdown

A

complex organic compounds

-providing energy

46
Q

Anabolic reactions synthesize

A

complex molecules from small molecules

-requiring energy

47
Q

Each cell has about 1 billion ATP molecules that last for

A

less than one minute

48
Q

Over half of the energy released from ATP is converted to

A

heat

49
Q

Energy is found in the

A

bonds between atoms

50
Q

Oxidation is a

A

decrease in the energy content

51
Q

Reduction is the

A

increase in the energy content

52
Q

Oxidation-reduction reactions are always coupled within

A

the body

53
Q

Phosphorylation is

A

ADP + P = ATP

3rd phosphate group

54
Q

Mechanisms of phosphorylation:

A

within animals

55
Q

Gluconeogenesis:

A

Liver glycogen runs low if fasting, starving forcing formation from other substances

56
Q

Gluconeogenesis stimulated by

A

cortisol (adrenal) & glucagon (pancreas)