chapter 23 - digestion

Question 1

primary organs

Answer 1

alimentary canal::

• mouth, pharynx, esophagus
• stomach, small intestine, large intestine

Question 2

accessory digestive organs

Answer 2

• teeth and tongue

- gallbladder, salivary glands, liver, pancreas

Question 3

ventral mesenteries

Answer 3

falciform ligament -> binds anterior part of liver to anterior abdominal wall
lesser omentum -> attaches liver to lesser curvature of the stomach

Question 4

dorsal mesenteries

Answer 4

greater omentum -> connects greater curvature or stomach to posterior abdominal wall
transverse mesocolon -> holds transverse colon in place
sigmoid mesocolon -> connects sigmoid colon to posterior pelvic wall

Question 5

intraperitoneal and secondarily retroperitoneal digestive organs

Answer 5

see diagram

Question 6

digestion processes

Answer 6

INGESTION –> PROPULSION –> MECHANICAL BREAKDOWN –> CHEMICAL DIGESTION –> ABSORPTION –> DEFECATION

Question 7

deciduous v permanent teeth

Answer 7

deciduous : ~20 teeth; first appear at 6 months

permanent: 32 teeth; most erupt by end of adolesence

Question 8

tooth structure

Answer 8

Crown –exposed surface
Root –in tooth socket
Enamel –outer translucent layer
Dentin –yellow that underlies enamel
Cementum –surrounds dentin in socket and connects to periodontal ligaments
Pulp cavity –center of tooth which holds blood vessels and nerves

Question 9

chief cells secretions

Answer 9

pepsin(ogen) –digests proteins

gastric lipase –digests fats

Question 10

parietal cells secretions

Answer 10

gastric acid (HCl) –activates pepsin; kills bacteria
intrinsic factor –complexes with vitamin B12 to permit absorption

Question 11

mucous cells secretions

Answer 11

mucus (surface cell) –physical barrier between lumen and epithelium
bicarbonate (neck cell) –buffers gastric acid to prevent damage to epithelium

Question 12

liver functions

Answer 12

largest gland in body w/ over 500 functions

digestive function –> bile production + many metabolic functions

Question 13

liver anatomy

Answer 13

each lobule is centered around a central vein that drains blood into hepatic vein
hepatocyte -> functional cells of liver

Question 14

hepatic portal system

Answer 14

• specialized part of vascular circuit
• picks up digested nutrients
• delivers nutrients to the liver for processing
• two capillary beds in small intestine + liver sinusoids

Question 15

gallbladder

Answer 15

• stores and concentrates bile (steroid acids: cholic, chenodeoxycholic and deoxycholic acids _ bilirubin and biliverdin)
• expels bile into duodenum
• ->bile emulsifies fats
• ->cholecystokinin (CCK) is released from enteroendocrine cells in response to fatty chime CCK

Question 16

pancreas functions

Answer 16

endocrine functions –> insulin and glucagon from islet cells; major regulatory hormones for energy metabolism
exocrine functions –? duct cells secrete majority of NaHCO3 needed to neutralize stomach acids + acinar cells make several digestive enzymes