Anatomy Final

Question 1

Digestive system functions

Answer 1

Ingestions
Motility
Secretion
Digestion (chemical and mechanical)
Absorption
Elimination

Question 2

Accessory organs

Answer 2

Teeth, Tongue, Salivary glands, Liver, Gallbladder, and Pancreas

Question 3

alimentary canal

Answer 3

oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anal canal

Question 4

Tunic layers ( In to out)

Answer 4

Mucosa, Submucosa, Muscularis, and Serosa

Question 5

Enteric nervous system

Answer 5

Baroreceptors and chemoreceptors detect changes in tract wall and chemical makeup of lumen content
Has: submucosal and myenteric plexus and sensory and motor neurons

Question 6

Sphincters

Answer 6

Close off lumen
controls movement of material into next section

Question 7

Oral cavity and Salivary Glands

Answer 7

mechanical digestion begins here
the saliva secreted in response to food
Contains salivary amylase: iniciates digestion of starch
Mixes with ingested materials to form bolus

Question 8

Pharynx

Answer 8

Bolus moves here for swallowing
- mucus secreted to facilitate swallowing

Question 9

Esophagus

Answer 9

Blus transported from Pharnyx into the stomach
- lubricated by mucus

Question 10

Stomach

Answer 10

Bolus mixes with gastric secretions during smooth muscle contractions
Secretions produced by stomach epithelial cells

Question 11

Saliva

Answer 11

99.5% made of water and solute mixture
Amylase, mucin, and lysozyme added
Iniciates chemical breakdown of starch
- lysosome antibodies inhibit bacteria growth
1-1.5 L secreted daily

Question 12

Mastication

Answer 12

Chewing; increases the surface area of food to expose ti more digestive enzymes
- coordinated activity within teeth, jaw, lips, tongue, and cheeks
- controlled by nuclei in medulla and pons: Mastication center

Question 13

Phases of swallowing

Answer 13

Voluntary: Food is pushed by the tongue against the hard palate to the oropharynx
Pharyngeal: Soft palate and uvula close off nasopharynx
- Larynx elevates so the epiglottis closes over laryngeal opening
Esophageal: Soft palate, uvula, and epiglottis return to the original position and the esophageal sphincter closes
- Bolus passes through the esophagus and enters into the stomach as the inferior esophageal sphincter opens. ( peristaltic contractions of esophageal muscle push bolus toward the stomach)

Question 14

Stomach

Answer 14

Resides in the left abdominal quadrant under the diaphragm
Chemical and Mechanical digestion take place
Digestion of fat and protein begins
ingested materials spend 2-6 hours here
Absorption of only small nonpolar substances

Question 15

Gastric secretions

Answer 15

5 types: 4 produce gastric juice; 1 secretes hormone
Surface Mucous cells
Mucous Neck cells
Parietal cells
Chief cells
G- cells

Question 16

Surface Mucous cells

Answer 16

Line stomach lumen and extends into gastric pits, secrete alkaline product containing mucous
- mucous helps to prevent ulceration of stomach lining
- protects from gastric enzymes and high acidity

Question 17

Mucous neck cells

Answer 17

immediately deep to the gastric pit
produce acidic mucin and helps to maintain acidic conditions
- protect stomach lining from abrasions and injuries

Question 18

Parietal cells

Answer 18

add insintric factor and hydrochloric acid
Insintric factor: essential for the absorption of B12 and production of normal erythrocytes
Hydrochloric acid: Responsible for low pH

Question 19

Hydrochloric acid functions

Answer 19

Converts inactive pepsinogen to active pepsin
Denatures proteins
Kills most organisms entering the stomach
Helps break down plant cell walls and animal CT

Question 20

Chief cells

Answer 20

most numerous secretory cells in the gastric gland
Produce and secrete zymogen granules
Produce gastric lipase: limited role in fat digestion

Question 21

G- cells

Answer 21

Enteroendocrine cells widely distributed in gastric glands
Secrete gastrin hormone which stimulates secretions and motility

Question 22

Gastric mixing and emptying

Answer 22

contraction of smooth muscle mix bolus with gastric secretions to form chyme
peristalic waves result in pressure gradients that move stomach contents toward the pyloric region
the pressure gradient applies force against the pyloric sphincter
sphincter opens and a small amount enters Duodenum
sphincter closes and retropulsion occurs

Question 23

Small intestine

Answer 23

ingested nutrients reside here at least 12 hrs
absorbs most nutrients, water, vitamins, and electrolytes

Question 24

Duodenum

Answer 24

Continuous with the jejunum at duodenojejunal flexure
most retroperitoneal
receives accessory gland secretions from liver, gallbladder, pancreas, and chyme from stomach

Question 25

Jejunum

Answer 25

Primary region from chemical digestion and nutrient absorption intraperitoneal and suspended by mesentery

Question 26

Ileum

Answer 26

Distal end terminates at ileocecal valve which is the sphincter controlling entry into large intestine - intraperitoneal and suspended by mesentery - continues absorption of digested material

Question 27

Large intestine

Answer 27

Absorbs water and electrolytes from remianing digested material - absorbs vitamin B and K - watery chyme turns into feces and stores them until defecation - from ileocecal junction to termination at anus

Question 28

Liver

Answer 28

Right upper quadrant - largest internal organ - covered by CT capsule and layer layer of visceral peritoneum - production of bile is main function

Question 29

Bile

Answer 29

Secreted by liver Contains: water, bicarbonate ions, bile pigments, cholesterol, bile salts, lecithin, and mucin Bile salts and lecithin help ,mechanically digest lipids

Question 30

Gallbladder

Answer 30

Attached to the inferior surface of the liver - stores concentrates and releases bile connected to the common bile duct by the cystic duct sphincter valve ( hepatopancreatic sphincter) - controls bile into and out of gallbladder

Question 31

Pancreas

Answer 31

Endocrine function: produces and secretes insulin nd glucagon Exocrine function: produces pancreatic juice to assist with digestive activities Retroperitoneal organ - wide head, tail tapers as it approaches spleen

Question 32

Pancreatic Juice

Answer 32

Formed from secretions of acinar cells and pancreatic duct cells - alkaline fluid Mostly water, HCO3, digestive enzymes - pancreatic amylase to digest starch - pancreatic lipase to digest triglycerides - inactive proteases that digestions proteins when activated - nucleases for digestion for nucleic acids

Question 33

Hormones that control digestion

Answer 33

Gastrin: secreted bt G-cells; stimulated by bolus; Targets parietal cells: secretion of HCI chief cells: secretion of pepsinogen pyloric sphincter: stimulates contraction Cholecystokinin: secreted by Enteroendocrine; stimulated by chyme containing amino acids and fatty acids; Primary targets: Stomach: inhibits stomach motility and gastric secretion Pancreas: stimulation pancreatic juice Hepatopancreaic sphincter: Relaxation Secretin: secreted by enteroendocrine; stimulus is increase of acidity in chyme; Targets: Stomach: inhibits stomach motility and gastric secretion Pancreas: secretion of alkaline solution Liver:secretion of alkaline solution

Question 34

Carbohydrate digestion in small intestine

Answer 34

Pancreatic amylase produce and secreted into small intestine Pancreatic amylase continues digestion of strach that began in oral cavity by salivary amylase Brush border enzymes complete the breakdown of starch and are responsible for digestion of disaccharides

Question 35

Protein digestion in the small intestine

Answer 35

Proteolytic enzymes released from the pancreas Enteropeptidase to activates trypsinogen to trypsin and activates other proteolytic enzymes Activated pancreatic proteolytic enzymes break proteins into peptides and amino acids Brush border peptidases break peptides into single amino acids to be absorbed through epithelial cell into blood

Question 36

Lipid digestion and absorption in small intestine

Answer 36

Bile salts emulsify lipid droplets to form micelles Pancreatic lipase in micelles digest each triglyceride and two free fatty acids monoglycerides and free fatty acids enter an epithelial cell, bile salts remain in the intestinal lumen to be reabsorbed and recycled Triglycerides molecules reassembled within epithelial cells Lipids are then wrapped with protein to form a chylomicron. Chylomicrons are packaged within secretory vesicles and then exocytosed from the cells and absorbed into lacteals