Structure And Digestive Properties

Question 0

Jejunum

Answer 0

Enzymatic digestion and absorption

Question 1

Duodenum

Answer 1

Site of entry of pancreatic and biliary secretions

Question 2

Ileum

Answer 2

Reabsorption of bile salts

Hormone production

Question 3

Digestion

Answer 3

Breakdown of food molecules by enzyme action

Question 4

3 spatial categories of digestive enzymes

Answer 4

Intraluminal: secreted, work in the SI lumen

Membrane associated: apical membrane of epithelial cells

Intracellular: enzymes within the cells

Question 5

Pancreas

Answer 5

Enzyme secretion : trysinogen, amylase,lipase

Bicarbonate secretion
Hormone secretion

Question 6

Acinar cells

Answer 6

Exocrine secretion

Enzymes ( amylase,lipase)

Question 7

Duct cells

Answer 7

Exocrine secretions

Bicarbonate

Question 8

Trypsin

Answer 8

Activate the pancreatic zymogens

Question 9

Liver

Answer 9

Produces bile

Question 10

Gallbladder

Answer 10

Storage organ for bile

Question 11

Bile salts

Answer 11

Made from cholesterol

Modified to have polar end

Non polar interacts with fat

Question 12

Endocrine regulation of bile secretion

Answer 12

CCK: relaxes Sphincter of Oddi, gallbladder contractions

Secretin: bicarbonate secretion

Question 13

Positive Feedback of bile secretion

Answer 13

Bile acids reabsorbed in ileum and return to liver

Increases bile production as long as CCK keeps gallbladder contracting and sphincter open

Question 14

Absorption

Answer 14

Must cross apical and basolateral membrane

Question 15

Monosaccharides, amino acids and water soluble vitamins absorption

Answer 15

Carrier-mediated transport (active or passive)

Question 16

Electrolytes and mineral absorption

Answer 16

Through channels

Carrier mediated transport (active or passive)

Question 17

Fats and fat soluble vitamins absorption

Answer 17

Lipid micelles diffuse through membrane

Chylomicron synthesis and release into lymph

Question 18

Cecum

Answer 18

Blind sac
   Paired in birds
   Enlarged in hind guy fermenters
Microbial fermentation (some species) and VFA absorption
Water and electrolyte absorption

Question 19

Colon

Answer 19

Microbial fermentation ( some species) and VFA absorption 
Water abs electrolyte absorption

Question 20

Rectum

Answer 20

Not in birds, cloaca instead

Storage if feces prior to defecation

Question 21

Microbes –>

Answer 21

Fiber (cellulose)–> glucose –>VFA

Question 22

What does VFA stand for?

Answer 22

Volatile Fatty Acid

Question 23

3 types of VFAs

Answer 23

Acetic
Propionic
Butyric

Question 24

2 types of neurons in the enteric nervous system

Answer 24

Receptor and sensory neurons: mechanoreceptors and chemoreceptors Motor neurons: innervate gut muscle, blood vessel muscle, glands Release neurocrines

Question 25

Neurocrines

Answer 25

Released from motor neurons in response to an action potential

Question 26

ENS communicates with the CNS through autonomic nervous system

Answer 26

Parasympathetic motor neurons: stimulatory Sympathetic motor neurons: inhibitory

Question 27

Motility

Answer 27

Movement of gut wall

Question 28

Roles of motility

Answer 28

Moves digesta along GIT Retains digesta for digestion,absorption,storage Physically breaks down food, mix it with secretions Bring digesta in contact with absorptive surface

Question 29

Peristalsis

Answer 29

Main propulsive motility pattern Occurs from the esophagus to the end of the large intestine Coordinated contraction of longitudinal and circular smooth muscles

Question 30

Peristalsis behind the bolus

Answer 30

Circular muscles-contracted | Longitudinal muscles- relaxed

Question 31

Peristalsis ahead of the bolus

Answer 31

Circular muscles-relaxed | Longitudinal muscles-contracted

Question 32

Net effect of peristalsis

Answer 32

Bolus pushed down the GIT

Question 33

Segmentation

Answer 33

``` Non propulsive motility pattern Allows digesta to be retained in a segment of the intestine Allows mixing with secretions Gives time for absorption to occur Small and large intestine ```

Question 34

How does segmentation work?

Answer 34

Contraction of short segments of circular muscles creates areas of constricted and displayed lumen

Question 35

Avian foregut digestion: Crop

Answer 35

Mucous secretion

Question 36

Avian foregut digestion: proventriculus

Answer 36

Glands secrete acid, mucous and pepsinogen | Similar gastric,cephalic and intestinal phases as in mammals

Question 37

Gizzard

Answer 37

Muscular contractions move digesta between proventriculus, gizzard and duodenum

Question 38

Motility in the stomach: proximal region

Answer 38

Adaptive relaxation: stomach expands to accommodate digesta: storage Keeps pressure in stomach constant

Question 39

Motility in the stomach: distal region

Answer 39

Peristalsis: pushes digesta towards the pyloric sphincter (which is constricted) =mixing and grinding Only small particles can leave the stomach

Question 40

Small intestine motility: during digestion:

Answer 40

Peristalsis moves digesta for short distances, followed by cycles of segmentation contractions Moves digesta down GIT Allows for mixing and absorption

Question 41

Small intestine motility: inter digestive phase:

Answer 41

Powerful waves of peristalsis Covers large distances Pushes remaining material out of SI

Question 42

Large intestinal motility: segmentation

Answer 42

Allows for mixing, fermentation, and absorption (cecum and colon)

Question 43

Large intestinal motility: retropulsion(antiperistalsis)

Answer 43

In the colon, waves of contraction that move in the direction of the cecum/small intestine Retains digesta for longer, mixing Opposed by the inflow of digesta from the ileum In birds, moves material from cloaca back into LI

Question 44

Cellulose

Answer 44

Fiber β 1-4 linkages of glucose Mammalians cannot digest

Question 45

Starch

Answer 45

α 1-4 linkage

Question 46

Ruminants

Answer 46

Herbivores that consume a high fiber diet

Question 47

Examples of ruminants:

Answer 47

Cows sheep goats deer giraffes bison antelope oxen

Question 48

Ruminants 4 chambers

Answer 48

Reticulum Rumen Omasum Abomasum

Question 49

Pseudo ruminants

Answer 49

Camels llamas and alpacas do not have omasum

Question 50

Foregut fermenters

Answer 50

Microbes found in reticulum and rumen

Question 51

What is the difference in non ruminants and ruminants?

Answer 51

Foregut

Question 52

Mouth of a ruminant

Answer 52

No upper incisors

Question 53

Chewing of a ruminant

Answer 53

Vertical and lateral motion