unit 4 study guide

Question 1

describe the main functions of the digestive system

Answer 1

1. take in food
2. breaking it down into nutrient molecules
3. absorbing molecules into the bloodstream
4. ridding the body of any indigestible remains

Question 2

describe the difference between mechanical and chemical digestion

Answer 2

mechanical - chewing, mixing food with saliva, chumming food in stomach, and segmentation

Question 3

segmentation

Answer 3

local constriction of intestine that mixes food with digestive juices

Question 4

1st layer of the digestive tract

Answer 4

1. mucosa: tunic layer that lines lumen
   - secretes mucus, digestive enzymes, and hormones
   - absorbs end products of digestion
   - protects against infectious disease

Question 5

2nd layer of the digestive tract

Answer 5

2. submucosa
   - consists of areolar connective tissue
   - contains blood and lymphatic vessels
   - has an abundant amount of elastic tissues

Question 6

3rd layer of the digestive tract

Answer 6

3. muscularis externa
   - muscle layer responsible for segmentation and peristalsis
   - circular, longitudinal muscle

Question 7

4th layer of the digestive tract

Answer 7

4. serosa
   - outermost layer
   - made up of visceral peritoneum

Question 8

mesentery

Answer 8

double layer of peritoneum

Question 9

splanchnic circulation

Answer 9

arteries that branch off aorta to serve digestive organs

Question 10

hepatic portal circulation

Answer 10

drains nutrient-rich blood from digestive organs
delivers blood to liver for processing

Question 11

mouth

Answer 11

food is chewed and mixed with enzyme-containing saliva that begins process of digestion, and swallowing process is initiated
-soft and hard palate

Question 12

tongue

Answer 12

occupies the floor of the mouth
- gripping, repositioning, and mixing of food during chewing
- formation of bolus, mixture of food and saliva

Question 13

lingual frenulum

Answer 13

attachment to floor of mouth

Question 14

ankyloglossia

Answer 14

congenital condition in which children are born with an extremely short lingual frenulum (tongue tied)

Question 15

saliva

Answer 15

-cleanses mouth
- dissolves food chemicals for taste
- begins breakdown of starch with enzyme amylase

Question 16

salivary glands

Answer 16

parotid
submandibular
sublingual

Question 17

salivary glands composed of what cells

Answer 17

1. serous cells: produce watery secretion, enzymes, ions, bit of mucin
2. mucous cells: produce mucus

Question 18

composition of saliva

Answer 18

• mostly water
• slightly acidic
• electrolytes
• contains enzymes salivary amylase and lingual lipase
• proteins
  -metabolic wastes: urea, igA
  -lysozyme`

Question 19

teeth

Answer 19

lie in sockets in gum covered margins
-mastication

Question 20

pharynx

Answer 20

allows passage of food, fluids, and air

Question 21

esophagus

Answer 21

flat muscular tube that runs from laryngopharynx to stomach

Question 22

heartburn

Answer 22

cause by stomach acid regulating into esophagus

Question 23

deglutition

Answer 23

1. buccal phase - voluntary contraction of tongue
2. pharyngeal-esophageal phase - involuntary contraction

Question 24

stomach

Answer 24

temporary storage tank that starts chemical breakdown of protein digestion

Question 25

chyme

Answer 25

bolus of food to paste

Question 26

types of gland cells of the stomach

Answer 26

1. mucous neck cells secrete thin, acid mucus 2. parietal cells secrete hydrochloric acid (HCL) - denatures protein, activates pepsin intrinsic factor - required for absorption of vitamin B12 2. chief cells secrete pepsinogen , that is activated by pepsin pepsin lipase 4. enteroendocrine cells paracrine: serotonin & histamine Hormones: somatostatin & gastrin

Question 27

gastrin

Answer 27

stimulates HCI secretion in stomach

Question 28

somatostatin

Answer 28

inhibits GI activity and the secretion of insulin and glucagon

Question 29

bile

Answer 29

fat emulsifier

Question 30

galbladder

Answer 30

storage of bile

Question 31

liver

Answer 31

digestive function is production of bile - detoxifies blood - removes and stores nutrients - stores iron and vitamins A,D,E, and K - produces urea after breaking down amino acids

Question 32

hepatic artery

Answer 32

supplies oxygen

Question 33

hepocytes

Answer 33

increased rough and smooth ER, Golgi apparatus, peroxisomes, and mitochondria

Question 34

jaundice

Answer 34

can be cause by liver failure - blockage can cause bile salts and pigments to build up in blood

Question 35

exocrine

Answer 35

produce pancreatic juice

Question 36

endocrine

Answer 36

secretion of insulin and glucagon `

Question 37

amylase

Answer 37

digest starch (carbs)

Question 38

lipase

Answer 38

digest fat

Question 39

nucleases

Answer 39

break down nucleic acids

Question 40

protease enzymes

Answer 40

for protein digestion

Question 41

secretin

Answer 41

secreted by duodenum

Question 42

secretin

Answer 42

secreted by duodenum when secreted by HCI and chyme, the gall bladder is stimulated to release bile and pancreatic juice

Question 43

cholecystokinin (CCK)

Answer 43

release by the duodenum when proteins and fats are present stimulates output of pancreatic juice

Question 44

small intestine

Answer 44

the major organ of digestion and absorption

Question 45

ileocecal valve

Answer 45

point at which it joins large intestine.

Question 46

villi

Answer 46

fingerlike projections of mucosa lymphatic capillary- lacteal for absorption

Question 47

microvilli

Answer 47

cytoplasmic extensions of mucosal cell that give fuzzy appearance brush border- final carbohydrate and protein digestion

Question 48

intestinal crypts

Answer 48

tubular glands scattered between villi

Question 49

villi

Answer 49

absorbs nutrients and electrolytes

Question 50

crypts

Answer 50

produce intestinal juice, carrier fluid for chyme

Question 51

peyers patches

Answer 51

aggregated lymphoid nodules

Question 52

lamina propria

Answer 52

also contains large numbers of plasma cells that secrete igA

Question 53

large intestine

Answer 53

- propulsion of feces to anus and defecation - vitamins, water, and electrolytes are reclaimed

Question 54

digestion

Answer 54

catabolic process that breaks macromolecules down into monomers small enough for absorption

Question 55

hydrolysis

Answer 55

water is added to break chemical bonds

Question 56

absorption

Answer 56

is the process of moving substances from lumen of gut into body

Question 57

emulsification

Answer 57

triglycerides and their breakdown products are insoluble in water

Question 58

diffusion

Answer 58

lipid products leave micelles and cross epithelial membrane via diffusion

Question 59

anabolism

Answer 59

synthesis of large molecules from small ones

Question 60

catabolism

Answer 60

hydrolysis of complex structures to simpler ones

Question 61

post absorptive state

Answer 61

- catabolism of fat, glycogen, and proteins exceeds anabolism

Question 62

insulin

Answer 62

hormone that stimulates glucose uptake

Question 63

glucacon

Answer 63

hormone that stimulates a rise in blood glucose levels

Question 64

metabolic role of the liver

Answer 64

- process nearly every class of nutrient - maintains blood glucose levels -primary site of fat metabolism - site of plasma protein metabolism - regulating plasma cholesterol levels - store vitamins and minerals - metabolize alcohol, drugs, hormones, and bilirubin

Question 65

glycolysis

Answer 65

converts glucose to pyruvic acid

Question 66

glycogenesis

Answer 66

polymerizes glucose to form glycogen

Question 67

glycogenolysis

Answer 67

hydrolyzes glycogen to glucose monomers

Question 68

gluconeogenesis

Answer 68

forms glucose from noncarbohydrate precursors