Unit 2: Chapter 36

Question 1

Function of the GI Tract

Answer 1

Digest food and absorb nutrients into the blood stream by motility, secretion, digestion and absorption.

Question 2

Upper Part

Answer 2

Mouth
Espophagus
Stomach
Acts as an intake source and receptacle through which food passes and in with digestion princess takes place

Question 3

Middle Portion

Answer 3

Duodenum
Jejunum
Ileum
Is where most digestive and abortion take place

Question 4

Lower Segment

Answer 4

Cecum
Colon
Rectum
Serves as a storage channel for the efficient elimination of waster

Question 5

Accessory Organs

Answer 5

Salivary glands
Liver
Pancreas
Produce secretions that aid in digestion

Question 6

First Layer of GI Wall Structure

Answer 6

Inner layer
Made up of a lining epithelium, an underlying CT called lamina propria
Muscular is mucosal composed of smooth muscle cells that can contract and change shape and surface area of the muscular layer

Question 7

Mucosal Layer of Inner Layer

Answer 7

Production of the mucus that lubricates and protects the inner surface of the alimentary canal
Secretion of the digestive enzymes and substances that break down food
Absorption of the breakdown products of digestion
Maintenance of a barrier to prevent the entry of noxious substances and pathogenic organisms

Question 8

Second Layer of GI Wall Structure

Answer 8

Submucosal layer
Consits of dense CT and aggregates of adipose tissue
Contains blood vessel, nerves and structures responsible for secreting digestive enzymes

Question 9

Third Layer of GI Wall Structure

Answer 9

Muscularis externa
Consists of an inner later of circularly arranges smooth muscle cells
An outer later of longitudinally arranges smooth muslce layers which facilitate movement of contents of the GI tract.

Question 10

Fourth Layer of GI Wall Structure

Answer 10

Outer most layer
Serosal layer
Serous membrane consisting of the mesothelium which is composed of a layer of simple squamous epithelium and underlying CT.

Question 11

Peritoneum

Answer 11

Largest serous membrane int he body having a surface area aprox equal to that of the skin
Consists of 2 continuous layers
1. Visceral
2. Parietal

Question 12

Enteric NS Motility

Answer 12

GI has own nervous system
Composed mainly of 2 plexuses:
1. Outer myenteric (Auerbach) plexus that is located beterrn the longitudinal and circular layers of smooth muscle cells
Controls mainly intestinal movements along hte length of the gut

2. Inner submucosal (Meissen) plexus that lies between the mucosal and circular muscle layers
   Concerned mainly with controlling the function within each segment of the intestine

Question 13

Autonomic NS Motility

Answer 13

Intestine is innvertated by the PNS and SNS branches of the ANS.
PNS is supplied mainly by the vagus nerve with postganglionic nervous located primarily in the myenteric and submucosal plexuses. Increased intestinal motility and secretory activity.
SNS is supplied by nerves that run between the spinal cord and the pre vertebral ganglia and between these ganglia and the intestine

Question 14

Intestinal Smoot Muscle GI Motility

Answer 14

Has its own intrinsic slow wave activity which varies from about 12 per minute int he duodenum to 8 or 9 mins int he ileum
Detemined the rate of smooth muscle contractions

Question 15

Swallowing Center

Answer 15

Medulla and the lower pons

Question 16

Colonic Motility

Answer 16

2 types of
1. Segmental mixing movements
Called austral churning because they occur within compartments called haustral
Involve filling and expelling
2. Propulsive mass movements
Large segments of hte colon contacts an a unit moving the fecal contents forward
Last 30 second followed by 2-3 min relaxation

Question 17

Normal Colonic Transit

Answer 17

Time 24 to 48 hours and normal stool is composed of 75% water and 25% solid matter

Question 18

Defection

Answer 18

Controlled by action of 2 sphincters
1. Internal: several cm long, circular thickening of smooth muscle that lies inside the anus
2. external: composed of striated voluntary muscle, surrounds the internal sphincter
Controlled by punenal nerve

Question 19

Cholecystokinin

Answer 19

Duodenum, jejunum
Products of protein digestion and long chain fatty acids
Stimulates contraction of gallbladder and secretion of pancreatic enzymes
Slows gastric melting
Inhibits food intake

Question 20

Gastric

Answer 20

Antrum of stomach, duodenum
Vagal stimulation, epinephrine, calcium containing foods, alcohol

Stimulates secretion of gastric acid and pepsinogen; increases gastric blood flow; stimulates gastric smooth muscle contractions; stimulates growth of gastric and intestinal mucosal cells

Question 21

Sti

Question 22

Ghrelin

Answer 22

Fundus of stomach
Nutritional fasting and hormonal

Stimulates secretion of growth hormone; acts as an appetite-stimulating signal from stomach when an increase in metabolic efficiency is necessary

Question 23

Glucagon Like Peptide 1

Answer 23

Distal small intestine
High carb foods
Augments insulin releases
Suppresses glucagon releases
Slows gastric emptying decreased appetite and bloody weight

Question 24

Glucose Dependent Insulinotropic Polypeptide

Answer 24

Small intestine, mainly jejunum
High carb meal
Augments insulin releases

Question 25

Gastrointestinal Secretions

Answer 25

Secretory glands have 2 basic functions 1. Production of mucus to lubricate and protect the mucosal layer of the GI tract wall 2. Secretion of fluids and enzymes to aid in the digestion and absorption of nutrients Each day, 7000mL of fluid is secreted into the GI tract 100 to 200 mL of this fluid will leave the body in stool Remainder is absorbed into small/large intestine

Question 26

Secretin

Answer 26

Duodenum Acid pH or chyme entering duodenum pH < 3.0

Question 27

Salivary Secretions

Answer 27

Glands consit of parotid, submaxillary, sublingual and baccal glands Saliva 3 functions 1. Protection and lubrication 2. Protective antimicrobial actions 3. Contains ptyalin and amylase which initiate the digestion of dietary starches

Question 28

Nerve Systems that Regulate Salivary Secretions

Answer 28

ANS primarily regualted secretions from salivary glands PNS stimulation increase flow SNS decreased flow

Question 29

Mucosal Barrier

Answer 29

Implantation characteristics of gastric mucosa is resistance to the highly acidic secretions that it produces .

Question 30

Mucosal Barrier and NSAIDS

Answer 30

When taking NSAIDS, it damages the barrier causing disruption causing hydrogen ions to move into the tissue where they accumulate. Intracellular oh decreased enzymatic reactions become impaired and cellular structure are distrusted

Question 31

Intestinal Secretions

Answer 31

Small intestine secretes digestive juices and reviews secretions from the liver and pancreas

Question 32

Bruner Glands

Answer 32

Extensive array of mucous producing glands Are concentratated at the site where they accumulate contents fromt he stomach and secretions from the liver and pancreas enter the duodenum. Secrete large amounts of alkaline mucus that protects the duodenum from the acid contents in the gastric chyme and from the action of the digestive enzymes.

Question 33

Bruner Glands and the ANS

Answer 33

Strongly influenced by ANS activity This stimulation causes a marked decreased in mucous production leaving the area more susceptible to irritation

Question 34

Intestinal Flora

Answer 34

Functions of mucrolfora include metabolic activities that salvage energy and absorbable nutrients, tropic effects on intestinal epithelial cells and protection of the colonized host against invasion by pathogenic organism

Question 35

Colonic Microflora

Answer 35

Fermentation of indigestible dietary reside and endogenous mucus produced by the epithelial cells

Question 36

Digestion

Answer 36

Process of dismantling foods into their constituent parts Requires hydrolysis, enzyme cleavage and fat emulsification Akthough Carbs and proteins diction begins in the stomach, digestion takes place mainly in small intestine

Question 37

Absorption

Answer 37

Process of moving until rents and other material from the external environment in the lumen of the GI tract into the internal environment. Accomplished by active transport and diffusion.

Question 38

Vitamin B12

Answer 38

Not absorbed in the a sense of intrinsic factor, which is secreted by the parietal cells of the stomach.

Question 39

Pyloric Sphincter in Relation to Intestinal Secretions

Answer 39

Critical gate keeper between the stomach and small intestines Controling the rate at which highly acidic chyme enters the duodenum. Prevents regulations of internal contents back into the stomach

Question 40

Mastication

Answer 40

Begin the digestive process Breaks down food into smaller pieces that can be easily swallowed. Food is lubricated with saliva and exposed to salivary amylase which breaks down starch containing foods Voluntary act

Question 41

GERD