Digestive system

Created by jacqui00 

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155 terms

Digestion

the process by which food substances are changed into forms that can be absorbed through cell membranes

organs of alimentray canal or GI tract

mouth(oral cavity); pharynx;esophagus;stomach;small intestines; large intestines

accessory organs

lips; teeth; tongue; salivary glands; liver; gallbladder; pancreas

layers of wall of GI tract

mucosa; submucosa; muscular layer; serosa;

mucosa

innerlining, made of mucosus membrane and thin layer of smooth muscle functions as protection underlying tissue and carrying on the processes of absorption and secretion

submucosa

made of loose connecctive tissue and many blood vessels, lymph vessels, nerves; functions of transporting newly-absorbed nutrients

muscular layer

inner layer encircles the GI tract and is responsible for the action of mixing the outer layer runs lengthwise along the GI tract and is responsible for the action of peristalsis

serosa

outer layer of the GI tract makes up the visceral peritoneum functions as lubrication so visceral organs can slide freely against one another

mixing movements and propelling movements

the motor functions of the alimentary canal

segmentation

a type of movement that aids mixing by alternately contracting and relaxing the smooth muscle in nonadjacent segments of the organ

peristalis

propelling movement that includes a wavelike motion in which a ring of contraction occures in the wall of the tube

submuscosal plexus

postaganglionic fibers located in the wall of the canal is important in controlling secretions by the GI tract

myenteric plexus

musclcular layer controls the GI motility inclued sensory neurons

parasympathetic impluses

these nerve impluses increase the activities of the digestive system

sympathetic impulses

these nerve impluses decrease the activites of the digestive system

mouth

first portion of the alimentary canal that recieves food and begins digestion

mastication

mechanically breakin up solid particles into smaller pieces and mixing them with saliva

lips

judge temperature and texture of foods

tongue

a thick muscular organ that occupies the floor of the mouth and nearly fills the oral cavity when mouth is closed

lingual frenulum

mucous membrane covers the tongue and a membranous fold

papillae

rough projections that are on the surface of the tongue, some that contain taste buds

lingual tonsils

cover with rounded masses of lymphatic tissue

hyoid bone

where is the tongue anchored to

palate

forms the roof of the oral cavity and consists of hard anterior part and a soft posterior part

uvula

the soft palate forms a muscular arch which extends posteriorly and downward as a cone shaped projection

palatine tonsils

in the back of the mouth on either side of the tongue and closely associated with the palate are masses of lymphatic tissue

pharynegeal tonsils or adenoid

on the posterior wall of the pharynx above the border of the soft palate if enlarged may block the passage between the nasal cavity and pharynx

teeth

the hardest structure in the body

primary or deciduos teeth

first set usually erupts througth the gums between 6 mth and 24 month or 2 1/2 years

gingiva

gums

what happens to the root of the decidous teeth

the roots are absorbed and then the tooth is pushed out of its socket by a permant tooth

when do permant tooth come in

starts about 6 yrs old

20

the amount of decidous teeth there is

incisors

2 in each quater of the upper and lower jaw= 8

canines

1 in each quater of the upper and lower jaw=4

permolars

2 in each quater of the upper and lower jaw=8

molars

3 in each half of upper and lower jaws=12

32

the total amount of permant teeth

crown

covered with enamel, superior to the gum

root

anchored b periodontal ligament; cementum encloses root and anchors bone to the jaw

dentine

the layer beneath enamel

pulp cavity

surrounded by dentine; containg blood vessels, nerves connective tissue

cavities

prodeced by bacteria that convert carbohydrate to acid

gingivitis nd peridontitis

gum disease or inflammation of the gums

neck

portion of where the gum comes and meets the tooth

root

below the gum

layers of the tooth

enamel ; dentine ; cementum; periodontal membrane or ligament

salivary glands

parotid (2), submandibular (2), sublingual glands(2)

parotid glands

anteior to each ear; largest salivary gland

mumps

enlargement of the parotid caused a virus

serous cells

the cells that secret salivary amylase which begins digestion of carbohydrates

submandibular glands

located in the floor of the mouth on the inside surface of the lower jaw....contains mostly serous cells which secrete amylase and a few mucous cells which secrete muscus

sublingual glands

the smallest of the major salivary glands located on the floor of the mouth inferior to the tongue. primarly serect muscus cells

movements of the GI tubes

mixing and propelling by peristalsis

pharynx

located behind mouth ; connects nasal aond oral cavities

masopharynx

pharyngeal tonsils , openings of internal nares and eustachian tubes

oropharynx

palatien tonsils

laryngopharynx

lingual tonsils and larynx

swallowing mechanism

sesory receptors in teh pharynx ssend impulses over vagus nerve, triggering this reflex

tonge in swallowing mechanism

raised against palate; noves blous of food into pharynx

soft palate

raises to close the internal nares

epiglottis

cove glottis to prevent food from entering trachea

esophagus

opens

peristalitc wave

forces the food into the esophagus

esophagus

lies posterior to the trachea

esophagus

enters stomach via esophageal sphincter whch prevent regurgiatation

reflux heart burn

occurs if the the esophageal sphincter doesn't close and allow reflux of gastric juices into esophagus

stomach

J-shaped organ that lies under the diaphragm

rugae

innter lining of stomach that has fold allow for expansion

function of stomach

mix food with gastric juices (chyme) to initiate protein digestion

cardiac

part of the stomach that surround the lower esophageal sphincter

fundus

rounded portion above and to the left of teh cardiac

body

large central portion of the stomach

pylorus

inferior region which leads into the pyloric sphincter

cells produced by gastric glands

mucous cells; chief cells; parietal cells

mucous

the cells of the gastric glands that secrete protective coating of mucus

chief cells

the cells of the gastric gland that secrete pepsinogen

parietal cells

the cells of the gastric gland that secrete HCl

pepsin

pepsinogen plus HCl form

pepsin

initates protein digestion

regulation of gastric secretion

cephalic, gastric, intestinal, and inhibition of gastric secretion

cephalic phase

this is initated by tase, smell or thought of food. Causing the reflex center in the Medulla Oblongata to initiate nerve impluses that travel on the PNS whick innervate the stomach

cells involed in the cephalic phase

gastric cells that secrete pepsin for protein digestion and endocrine cells of the stomach that secrete hormones

gastrin

secreted by the endocrine cells in the stomach, which stimulates the gastric glands

gastric phase

initiated by the presence of food in the stomach. Distetnsion stiumlated the stoamch mechanoreceptor. Impulse sare sent to ethe medulla Oblongata to stimulate the release of gastrin for mteh stomach

what controls the release of gastrin

the medulla Oblongata

intestinal phase

intiated by the presence of acidic chyme entering the duodenum

gastrin

this is secreted by duodenum to travels to the stomach and stimulate the gastric glands

secretion

secreted by duodenum which inhibits gastric juice secretion

inhibition of gastric secretion

duodenum release secretion, secretin inhibits gastric glands of stomach , fatty acids in teh duodenum case the relase of cholecystokinin

cholecystokinin

release by the duodenum by fatty acids causing the inhibition of gastric juices

location of ulcers in the stomach

gastric and duodenal

causes of ulcer

stress, H.pylori, drugs

mixing and emptying action of the stomach

1. food mixed with gastric juice called chyme 2 fluid pass more readily than soilds, carbohydrates pass more readily than proteins which pass more readily thant fats

vomiting

initiated from reflex in the medulla oblongota, triggered by irritation or distension in the stomach, some drugs, toxins and sometimes rapid change in body motion

pancreas

an exocrine and endocrine gland

where doese the pancrease secret substances

as and exocrine gland it secrets pancreatic juices into the duodenum

pancreatic amylase

breaks down starches and glycogent into disaccharides

pancreatic lipase

breasks down fats into fatty acids and glycerol

trysin, chymotrypsin

breaks down proteins or partially disgested proteins into peptiedes

carboxypeptdiase

breaks down peptides into amino acids

nucleases

breaks down nucleica acids into nucloetides

pancreatic juice

from outline: pancreatic amlases, lipase, proteinase, nucleases

regluation of the pacreatic secretions

PNS by impluses that stimulate release pancreatic juice and the endocrine system with secretin a hormone tha release of pancreatic juices in response to acid chyme entering the duodenum

mouth

this is where the digestion of carbohydrates begin, with the amylase secretions

stomach

this is where the digestion of proteins begin with the secretion of pepsin

how is pepsin made

the chief cells in stomach secrete pepsinogen and the parietral cells of the stomach secrete HCl and the two combine and form pepsin

what is the puprose for pepsin

itinates the digestion of protein in the stomach

liver

this is the largest gland of the body located in the right hypochondriac and epigastric regions

how many and what are the lobes of the liver

4 lobes, right lobe , left lobe , caudate and quadrate lobes

hepatic lobules

the unctionsl units of the liver

hepatic sinusoids

instead of typical capillaries these are the vascular channels that get nutrients and oxygen form the hepatic portal vein and heaptic artery

kupffer cells

these are the cells that are located in the hepatic sinusoids that pagocytize bateria from the blood

jaundice

if the hepatic duct or the common bile duct become obstructed this occurs

liver

this functions to manufactor bile salt,breaks down toxic substances from the blood, manufactures plasma proteins and heparin, stores substances such a iron, copper, and vitamins A,D,E,K and B12

hepatic cells

the cells of the liver that secreted bile

7.6- 8.6

alkaline pH of bile

1 quart

the amount of bile made daily

bile

contains emulsified fats, pigment for the breakdown of RBC's cholesterol and electorlytes

cholerterol

remains in the bile solution and can precipitate and crystalize to form gallstones, if wedged in the bile duct the gallbladder may need to be removed

kupffer cells

cells in liver phagoctyize blood cell debris and bacteria

gallbladder

a pear shaped sac, connected to hte posterior side of teh liver by the cystic duct..

hepatic and cystic ducts

the ducts tha combine to forn teh common bile duct

funciton of the GB

stores and concentrates bile; release the bile inot small intestine to emulsify fats

cholecystokinin

when fatty acied are in the small intestines this is released by the small intestines , it stimulate the gallbladder to relase bile which helps emulsify fats

gallstones

when cholesterol in teh bile precipitates out and forms cyrstals

jaundice and pain

if stones leave the gallbladder and get lodged in the bile duct

part of the small intestines

duodenum, jejunum and ileum

duodenum

the smallest portion of the small intestines, that has numerous villi and contain mucus secreting glands whic form a pretective coating to protect the linging from gastric acids

ileum

extens for the jejunum to the ileocceal sphincter, has numerous lymph nodes called Peyer's patches

mesentery

the supportive tissue that suspends the duodenum and the ileum

Villi

1 mm finger like progjections of the mucose layer of teh small intestinal wall to enlarge surface space to amplify intestines absorption function

lacteal

the lumphatic vessels that is contained in the villi capillaries for nutrient absorption for fat

microvilli

cilia like projections on the villi that contain intestinal digestive enzymes

carboydrate digestion

begins in the mouth with salivary amylase and is completed in the small intestines with pancratic amylasea nd intestinal enzymes maltase, sucrase, and lactase

what happens to simple sugars in the small intestins

glucose and fructose are basorbed by e facilitated diffusion or active transport

protein digestion

begins in the stomach with pepsin, and is completed in the small intestines with the pancreatic proteinases, and peptidases, and intestial peptidase that break proteins down into amino acids

AMINO ACIDS

after protein is broken down this is absorbed into the villi via active transport into capillaries of villi where they are carried way by the blood

small intestines

where does fat digestion begin

fat digesion

beginning in the small intestion with the enzyme pancratic lipase, and completed with intestinal enzyme intestinal lipase producing fatty acids (FA)

short chain

the fatty acid chain that is absorbed by the villi via diffusion

long chain of FA

the fatty acid chain that is reorganized into triglcerides,

lipoprotein

the triglycerides become incased in the portein to produce this, the protein help transport the lipid...it get transported to the tissues for membrane and hormone synthesis

atherosclerosis

if cholesterol gets deposited in arteries in route to tissue memberanes it leads to

movement of the small intestines

weak peristalic contraction of movement that takes chyme 3-5 hours to move through the intesines

large intestinal movement

massive movement of peristalitc waves that occure only 2-3 times per day and pushes resiude toward the

patrs of teh large intestine

begin where ileum joint the cecum (ileocecall valve): colon asending, transverse, desending, sigmoid, rectum

rectum

contain the anal canal, internal sphincter that is under involuntary control, external sphincter that is under voluntary control and anus

large intestine

very little digestive function, some rsidue is digested by baceria to produc some vitamins, absorbs much of the water and electorlytes, mucus and bacteria

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