Ch. 9: The Digestive System

Question 1

what are the starting and ending points of the alimentary canal

Answer 1

the mouth and the anus

Question 2

what occurs during mechanical digestion

Answer 2

large food particles are physically broken down into smaller food particles

no chemical bond breaking

Question 3

what occurs during chemical digestion

Answer 3

enzymatic cleavage of chemical bonds

Question 4

path of the digestive tract

Answer 4

oral cavity –> pharynx –> esophagus –> stomach –> small intestine –> large intestine –> rectum

Question 5

which branch of the nervous system governs digestion

Answer 5

parasympathetic –> enteric nervous system

peristalsis and secretions

Question 6

what enzymes are in saliva

Answer 6

salivary amylase and lipase

Question 7

what does salivary amylase do

Answer 7

hydrolyzes starch into smaller sugars

Question 8

what does lipase do

Answer 8

hydrolyzes lipids

Question 9

where is the nasopharynx located

Answer 9

behind the nasal cavity

Question 10

where is the oropharynx located

Answer 10

in the back of the mouth

Question 11

where is the laryngopharynx located

Answer 11

above the vocal cords

Question 12

what does the epiglottis cover

Answer 12

the larynx during swallowing

Question 13

what division of the nervous system controls the esophagus

Answer 13

somatic (voluntary) - upper aspect with skeletal muscle

autonomic (involuntary) - lower aspect with smooth muscle

Question 14

what occurs when peristalsis is reversed

Answer 14

vomiting

Question 15

what does the lower esophageal sphincter divide

Answer 15

cardiac sphincter

esophagus and stomach

Question 16

how are the gastric gland governed

Answer 16

• glands in the upper stomach (fungus/body)
• sight/taste/smell activate PNS to send signals to the vagus nerve which prompts glands
• mucous, chief, and parietal cells

Question 17

what do mucous cells produce

Answer 17

bicarbonate-rich mucus that protects muscular wall from harsh acidic environment

Question 18

what do chief cells produce

Answer 18

pepsinogen (inactive form of pepsin)

proteolytic enzyme

Question 19

what do parietal cells produce

Answer 19

hydrochloric acid –> H+ ions cleave pepsinogen to pepsin

intrinsic factor –> absorbs vitamin B12

Question 20

what does pepsin do

Answer 20

cleaves peptide bonds near aromatic amino acids, resulting in short, peptide fragments

Question 21

what do the pyloric glands contain

Answer 21

G-cells

Question 22

what do G-cells produce

Answer 22

gastrin –> induces parietal cell secretion of HCl and stomach contraction

Question 23

chyme

Answer 23

acidic, semifluid mixture of partially digested food

Question 24

what are the segments of the small intestine

Answer 24

the duodenum, the jejunum, and the ileum

Question 25

what does the pyloric sphincter divide

Answer 25

stomach and the small intestine

Question 26

brush-border enzymes

Answer 26

- luminal surface of duodenum - secreted in presence of chyme - disaccharidases and peptidases --> break down dimers and trimers into absorbable monomers

Question 27

what occurs when disaccharides aren't broken down in the small intestine

Answer 27

- osmotic effect, water pulled into stool, diarrhea, | - bacteria hydrolyzes disaccharide, producing methane gas

Question 28

what does enteropeptidase do

Answer 28

activates trypsinogen to trypsin

Question 29

what does secretin do

Answer 29

- peptide hormone - causes release of pancreatic enzymes into duodenum - regulates digestive tract pH by reducing HCl secretions - slows motility of digestive tract

Question 30

what does cholecystokinin (CCK) do

Answer 30

- peptide hormone - simulates release of bile and pancreatic juices - promotes satiety in the brain

Question 31

what do bile salts do

Answer 31

- hydrophobic and hydrophilic regions | - emulsify fats and cholesterol into micelles

Question 32

are pancreatic juices acidic or basic

Answer 32

basic | - neutralize chyme, provide ideal pH for enzymes

Question 33

what are the secondary organs of digestion

Answer 33

pancreas, gallbladder, liver

Question 34

what do the acinar cells produce

Answer 34

pancreatic juices

Question 35

what are the pancreatic peptidases

Answer 35

trypsinogen, chymotrypsinogen, carboxypeptidases A and B --> ZYMOGEN FORMS Enteropeptidase (duodenum) converts trypsinogen to trypsin, which then converts the other zymogens

Question 36

what occurs in the hepatic portal vein

Answer 36

receives all blood from the abdominal portion of the digestive tract and allows the liver to process it before it is returned to the heart for oxygenation

Question 37

what is stored in the liver

Answer 37

triacylglycerols (fats)

Question 38

what is produced in the liver

Answer 38

- bile - glucose via glycogenolysis and gluconeogeneis - albumin (osmotic regulator) and clotting factor

Question 39

how is bile pigmented

Answer 39

bilirubin hemoglobin --> bilirubin --> conjugated to proteins in bile --> excreted, preventing jaundice

Question 40

what structures line the small intestine

Answer 40

villi with microvilli --> increased surface area

Question 41

what is a lacteal

Answer 41

lymphatic channel that takes up fats for transport to the lymphatic system

Question 42

how are simple carbs and amino acids absorbed into the blood from the small intestine

Answer 42

small intestine --> secondary (complementary) active transport and facilitated diffusion --> epithelium --> diffuse due to lower concentration gradient of monosaccharides and amino acids --> enter blood stream and go to liver

Question 43

how are small fatty acids absorbed into the blood from the small intestine

Answer 43

small intestine --> small fatty acids diffuse into capillaries d/t nonpolar

Question 44

how are larger fatty acids absorbed into the blood from the small intestine

Answer 44

move into intestinal cells --> modified into triglycerides and esterified cholesterol --> packaged into chylomicrons --> enter lymphatic system through lacteals

Question 45

how are vitamins absorbed

Answer 45

fat soluble --> chylomicrons --> lymphatic system water soluble --> absorbed with water by endothelial cells

Question 46

how does water exit the intestines

Answer 46

transcellularly through cell membranes and paracellularly between cells to reach the blood

Question 47

what are the divisions of the large intestine

Answer 47

the cecum, the colon, and the rectum

Question 48

what does the cecum do

Answer 48

accepts fluid exiting small intestines from through the ileocecal valve

Question 49

where does the appendix attach to the digestive system

Answer 49

the cecum

Question 50

what does the colon do

Answer 50

absorb water and salt from undigested material to concentrate it into feces

Question 51

what are the two structures that form the anus

Answer 51

internal sphincter (autonomic/involuntary control) external sphincter (somatic/voluntary control)