Gastrointestinal Tract & Motility

Question 1

describe the oropharyngeal stage of the swallow

Answer 1

1. at start of swallow, tongue presses bolus against hard palate
2. tongue propels bolus to pharynx
3. elevation of uvula prevents food from entering nasal
4. position of tongue prevents food from reeterning mouth
5. epiglottis folds over closed glottis
6. contraction of pharyngeal muscles pushes bolus through opened pharyngeosophageal sphincter into esophagus

Question 2

describe the oesophageal stage

Answer 2

1. pharyngeosophageal sphicter closes, oropharyngeal structures return to resting postition
2. peristalsis propels bolus down length of oesophagus
3. satroesophageal sphincter relaxes as peristalsis pushes bolus into stomach

Question 3

what are the layers of the digestive tract

Answer 3

1. serosa
2. muscularis externa (outer longitundinal muscle and inner circular muscle)
3. submucosa
4. mucosa (mucous membrane, lamina propia, muscularis mucosa)

Question 4

what is the intrinsic nervous system of the GI tract

Answer 4

the enteric nervous system

Question 5

where is the myenteric plexus

Answer 5

between the outer longitudinal and inner circular smooth muscle layers

Question 6

where is the submucosal plexus

Answer 6

between the circular muscle layer and the mucosa.

Question 7

what are the three sections of the stomach

Answer 7

fundus
body
antrum

Question 8

what secretory cells are in the oxynitic mucosa

Answer 8

mucous cells
chief cells
parietal cells
ECL cells

Question 9

what do muscous cells secret

Answer 9

alkaline mucous

Question 10

what do chief cells secret

Answer 10

pepsinogen (protien breakdown)

Question 11

what do parietal cells secret

Answer 11

hydrochloric acid
intrinstic factor

Question 12

what is the cardia

Answer 12

where. the oesophagus enters the stomach

Question 13

what endocrine cells are in the pyloric gland

Answer 13

G cells
D cells

Question 14

what do ECL cells secret

Answer 14

histamine (stimulates parietal cells)

Question 15

what do G cells secret

Answer 15

gastrin

Question 16

what do D cells secret

Answer 16

somatostatin (inhibits G cells, ECL and parietal cells)

Question 17

where are the two gastric glands

Answer 17

oxyntic mucosa - body of stomach
pyloric gland - antrum of stomach

Question 18

how is the mucosal barrier created

Answer 18

1. the luminal membranes of the gastric mucosal cells are impearmeable to H+ so that HCI (hydrochloric ions) cannot penetrate into cells
2. the cells are joined by tight junctions that prevent HCI from penetratig between them
3. the mucus coating over the gastric muscosa offers further protection

Question 19

what are the three parts of the small intestine

Answer 19

duodenum
jejunum
ileum

Question 20

what enzymes are bound in the villus membrane

Answer 20

Enteropeptidase
Disaccharidases
Aminopeptidases

Question 21

what is the function of the bound enzymes in the membrane of the villi

Answer 21

carbohydrate and protein digestion

Question 22

where is appendix

Answer 22

cecum

Question 23

what is the function of the sigmoid colon

Answer 23

to store fecal wastes until they are ready to leave the body

Question 24

what organ is a mixed gland

Answer 24

pancreas

Question 25

what cells in the pancreas are exocrine

Answer 25

duct cells (secret bicarbonate) and acinar cells

Question 26

what cells in the pancreas are endocrine

Answer 26

islets of lngerhans - secret insulin and glucagon

Question 27

what is the function of hepatic portal vein

Answer 27

carries nutrients from small intestine into liver

Question 28

where are interstitial cells of cajal

Answer 28

in inner circular muscle layer of the muiscularis externa

Question 29

what is the function of interstitial cells of cajal

Answer 29

produces wave like contractions to digestive systems

Question 30

how often does the entire stomach lining replace itself

Answer 30

every 3 days

Question 31

what is the border of the parotid gland

Answer 31

zygomatic arch, mandible, masseter muscle

Question 32

what does the parotid gland secrete

Answer 32

- amylase - saliva

Question 33

what type of gland is the parotid

Answer 33

serous

Question 34

where does the parotid duct drain

Answer 34

into cheek opposite maxillary 2nd molar (parotid papilla)

Question 35

where oe sthe submanidibular duct emerge

Answer 35

from deep part to open on sublingual papilla

Question 36

where does sublingual duct drain

Answer 36

*Drains into oral cavity via several minor ducts

Question 37

what type of gland is the sublingual

Answer 37

mixed serous and mucous gland

Question 38

what type of gland is the submandibular

Answer 38

seromucous gland

Question 39

what are the teniae coli

Answer 39

These are three longitudinal bands of muscle that run along the colon. They help in contracting the colon and forming haustra

Question 40

what are the haustra

Answer 40

These are pouches or sacs in the colon. They form due to the contraction of teniae coli and help in the slow movement of waste through the large intestine.

Question 41

what initiates contractions in the large intestine

Answer 41

BER (Basic Electrical Rhythm)

Question 42

what are the steps of the defaecation reflex

Answer 42

1. Feces move into and distend the rectum, stimulating strech receptors there. The receptors transmit signals along afferent fibers to spinal cord neurons 2. The spinal reflex is initiated in which parasympathetic motor fibers stimulate contraction of the rectum and sigmoid colon, and relaxation of the internal and sphincter 3. if it is convenient to defecate, voluntary motor neurons are inhibited, allowing the external anal sphincter to relax so feces may pass

Question 43

what permits defaecation

Answer 43

Voluntarily raising intra-abdominal pressure and relaxing external sphincter