Lecture 22

Question 1

Large intestine: Smooth muscle =

Answer 1

mechanical digestion

Question 2

Mechanical: Peristaltic waves:

Answer 2

haustral churning
gastroilial reflex
gastrocolic reflex

Question 3

haustral churning-

Answer 3

relaxed pouches are filled from below by muscular contractions

Question 4

gastroilial reflex =

Answer 4

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

Question 5

gastrocolic reflex =

Answer 5

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

Question 6

Chemical Digestion in Large Intestine:

Answer 6

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

Question 7

Bacteria ferment: 1st step

Answer 7

1. undigested carbohydrates into carbon dioxide & methane gas

Question 8

Bacteria ferment: 2nd step

Answer 8

2. undigested proteins into simpler substances (indoles)—-odor

Question 9

Bacteria ferment: 3rd step

Answer 9

3. turn bilirubin into simpler substances that produce color

Question 10

Absorption in the Large Intestine:

Answer 10

1. Some electrolytes—Na+ and Cl-

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

Question 11

Feces are

Answer 11

semisolid by time reaches transverse colon

Question 12

Feces =

Answer 12

dead epithelial cells, undigested food such as cellulose, bacteria

Question 13

Defecation: What moves feces into the rectum?

Answer 13

Gastrocolic reflex

Question 14

Defecation: What signals the sacral spinal cord?

Answer 14

stretch receptors

Question 15

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

Answer 15

parasympathetic nerves

Question 16

Defecation: What is voluntarily controlled?

Answer 16

external sphincter

Question 17

Diarrhea =

Answer 17

chyme passes too quickly through intestine

H2O not absorbed

Question 18

Constipation–

Answer 18

decreased intestinal motility

too much water reabsorbed

Question 19

Dietary fiber- Insoluble fiber:

Answer 19

• woody parts of plants

- speeds up transit time & reduces colon cancer

Question 20

Dietary fiber- Soluble fiber:

Answer 20

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

Question 21

How does soluble fiber lower blood cholesterol?

Answer 21

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

Question 22

Functions of food:

Answer 22

source of energy
essential nutrients
stored for future use

Question 23

Metabolism is

Answer 23

all the chemical reactions of the body

Question 24

Absorptive state:

Answer 24

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

Question 25

Postabsorptive state:

Answer 25

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

Question 26

Body cells use glucose for

Answer 26

ATP production

Question 27

Storage of excess fuels occur in

Answer 27

hepatocytes, adipocytes & skeletal muscle

Question 28

most glucose entering liver cells is converted to

Answer 28

glycogen (10%) or triglycerides (40%)

Question 29

dietary lipids are stored in

Answer 29

adipose tissue

Question 30

amino acids are

Answer 30

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

Question 31

amino acids not taken up by

Answer 31

hepatocytes used by other cells for synthesis of proteins

Question 32

Beta cells of pancreas release

Answer 32

insulin

Question 33

Insulin’s functions:

Answer 33

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

Question 34

Maintaining normal blood glucose level

Answer 34

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

Question 35

glucose enters blood from 3 major sources:

Answer 35

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

Question 36

alternative fuel sources are

Answer 36

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

Question 37

Most body tissue switch to

Answer 37

utilizing fatty acids, except brain still need glucose

Question 38

As blood glucose level declines

Answer 38

pancreatic alpha cells release glucagon

Question 39

glucagon stimulates

Answer 39

gluconeogenesis & glycogenolysis within the liver

Question 40

Hypothalamus detects

Answer 40

low blood sugar

Question 41

sympathetic neurons release

Answer 41

norepinephrine

Question 42

adrenal medulla releases

Answer 42

norepinephrine & epinephrine

Question 43

determining factor of starvation;

Answer 43

amount of adipose tissue

Question 44

Nutritional needs:

Answer 44

1. nervous tissue & RBC need glucose | 2. increase in formation of ketone bodies by liver cells

Question 45

Catabolic reactions breakdown

Answer 45

complex organic compounds | -providing energy

Question 46

Anabolic reactions synthesize

Answer 46

complex molecules from small molecules | -requiring energy

Question 47

Each cell has about 1 billion ATP molecules that last for

Answer 47

less than one minute

Question 48

Over half of the energy released from ATP is converted to

Answer 48

heat

Question 49

Energy is found in the

Answer 49

bonds between atoms

Question 50

Oxidation is a

Answer 50

decrease in the energy content

Question 51

Reduction is the

Answer 51

increase in the energy content

Question 52

Oxidation-reduction reactions are always coupled within

Answer 52

the body

Question 53

Phosphorylation is

Answer 53

ADP + P = ATP | 3rd phosphate group

Question 54

Mechanisms of phosphorylation:

Answer 54

within animals

Question 55

Gluconeogenesis:

Answer 55

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

Question 56

Gluconeogenesis stimulated by

Answer 56

cortisol (adrenal) & glucagon (pancreas)