Kinesiology 11

Front 1

GI tract

Back 1

digestive system - functions to break food down and absorb it. mouth--> pharynx--> esophagus --> stomach --> small intestine (duodenum, jejunum, ileum) -->large intestine (ascending colon, transverse colon, descending colon) --> rectum --> anal canal --> toilet.

Front 2

Accessory organs to GI tract?

Back 2

pancreas, liver, gall bladder.

Front 3

mucosa

Back 3

innermost layer of digestive tract.
thin epithelial cell layer which is generally highly folded, creating more available surface area for absorption. The thin epithelium is supported by the submucosa - (both by muscle and connective tissue, which also supplies it with blood and contains the necessary lymph tissue) to assist the mucosa in warding off disease.

Front 4

lumen

Back 4

space within the GI tract tube

Front 5

muscularis

Back 5

Two or three layers of smooth muscle below the mucosa and submucosa, also contains nerve cells - is responsible for the localized contraction of the muscles, moves food along the GI tract.

Front 6

DIGESTION

Back 6

breaking food into smaller pieces so that it can be absorbed

Front 7

absorption

Back 7

final products of digestion cross the mucosal layer and enter the body via the bloodstream.

Front 8

motility

Back 8

controlled by hormones and nerves, this is the movement of food and food particles down the GI tract.

Front 9

secretion

Back 9

production of enzymes and hormones to assist in digestion and absorption. These are both exocrine (into lumen of GI tract, i.e. saliva, stomach acid, bile, pancreatic juice) and endocrine, i.e. hormones which regulate exocrine secretions. (Gastrin)

Front 10

peristalsis

Back 10

A pattern of muscle contractions which occur in sequential waves in order to move the contents of hollow organs around. Examples of peristalsis occuring in the body are in the esophagus to move food, in the ureters to move urine, and in the uterus to move a baby towards parturition. A co-ordinated muscular activity, it is controlled by nerves.

Front 11

mouth

Back 11

primary role is to break down food into smaller chunks. includes substructures of teeth and tongue.

Front 12

salivary glands

Back 12

three sets (parotid, sublingual and submandibular) empty saliva into mouth via ducts.

Front 13

amylase

Back 13

enzyme found in saliva that breaks starch into disaccharides and tri-saccharides

Front 14

lipase

Back 14

contributes to digestion of triglycerides in mouth and GI tract.

Front 15

lysozome

Back 15

an enzyme in saliva that kills bacteria in the mouth

Front 16

saliva

Back 16

contains bicarbonate, enzymes and mucus
1. lubricates and moistens food
2. assist in digestion of starch
3. protects against tooth decay and gum disease by removing acid conditions and bacteria.

Front 17

glottis

Back 17

airway opening between vocal cords

Front 18

sphincter

Back 18

ringlike band of muscle that allows for partial or full closure of an orifice or passage.

Front 19

laryngopharynx

Back 19

area directly before the esophagus

Front 20

esophagus

Back 20

moves bolus of food quickly to the stomach by peristalsis.

Front 21

chyme

Back 21

watery fluid of gastric juices and partially digested food in the pyloris.

Front 22

pyloric sphincter

Back 22

at junction of stomach and small intestine

Front 23

fundus

Back 23

rounded portion of the stomach that functions mainly in food storage. muscles not as thick here as in pyloris area of stomach.

Front 24

gastric glands

Back 24

Deep pits within the mucosal layer of the stomach wall, gastric glands contain several different cell types, each secreting glandular substances which carry out important functions within the stomach.

Front 25

mucous cells of gastric gland

Back 25

secrete mucous to protect the cells lining the stomach from being digested by the gastric juices. These cells are located in the upper level of the gastric glands and on the mucosa surface.

Front 26

parietal cells of gastric gland

Back 26

secrete strong hydrochloric stomach acid and an absorption factor for vitamin B 12, called intrinsic factor.

Front 27

chief cells of gastric glands

Back 27

produce pepsinogen, an inactive form of the enzyme pepsin, which degrades protein.

Front 28

G cells of gastric glands

Back 28

secrete a hormone, gastrin, directly into the bloodstream (ENDOCRINE), which aids in gastric juice secretion and gastric motility.

Front 29

rugae

Back 29

many ridges that the empty stomach folds into, but expand out when full.

Front 30

intrinsic factor

Back 30

B12 absorption substance secreted from parietal cells

Front 31

pepsinogen

Back 31

inactive form of pepsin

Front 32

pepsin

Back 32

protein degrading enzyme is released by gastric glands in inactive form. When in contact with acid activates. pepsin itself can make more pepsin when contacting pepsinogen.

Front 33

gastric juice

Back 33

watery fluid created by the combination of secretions of parietal and chief cells, contains hydrochloric acid, intrinsic factor and pepsinogen/pepsin.

Front 34

gastrin

Back 34

hormone that controls gastric motility & secretion of gastric juices.

Front 35

secretin

Back 35

intestinal hormone which inhibits gastric motility

Front 36

cholecystokinin

Back 36

Secreted from the duodenum, cholecystokinin (or CCK) is a hormone which is secreted into the bloodstream when proteins and fats are present in the duodenum. CCK works with secretin (also from the small intestine) to increase the rate of secretion of bicarbonates by the pancreas, and also works to contract the gall bladder while relaxing the sphincter of Oddi. These two actions together deliver bile into the small intestine. Cholecystokinin enables the small intestine to continue its work of breaking down of food into constituent parts.

Front 37

STOMACH

Back 37

large J shaped organ important in storage, mixing of foo, and digestion of fat and proteins. the stomach does NOT function in ABSORPTION. composed of three parts: fundus, body, and pyloris.

Front 38

pancreas

Back 38

functions to neutralize chyme and add digestive enzymes to the stomach.elongated lobular organ below pyloris of stomach, connected to the small intestine via the pancreatic duct.

Front 39

pancreatic secretions

Back 39

bicarbonate pancreatic juice
pancreatic amylase
pancreatic lipase

Front 40

gallbladder

Back 40

stores and concentrates bile when no food is present. reabsorbs watter and sodium chloridefrom bile, concentrating it 8 - 10 times.

Front 41

liver

Back 41

synthesizes bile and bile salts req'd for fat digestion/absorption. processes and stores nutrients absorbed by intestines. helps control blood glucose concentration and stores glycogen, fats, vitamins and minerals. removes and destroys waste products and foreign particles. synthesizes plasma proteins: albumin and fibrinogen - important in clotting.

Front 42

duodenum

Back 42

first portion of the small intestine where bile and pancreati ducts empthy. Adjoins the pyloric sphincter.

Front 43

exocrine gland

Back 43

gland which empties its contents outside of the body (i.e. skin, GI tract, mouth, etc.)

Front 44

pancreatic juice

Back 44

watery solution containing bicarbonate and digestive enzymes secreted from the pancreas into the pancreatic and accessory exocrine ducts.

Front 45

acinar cells

Back 45

produce enzymes within the pancreas

Front 46

bile

Back 46

watery fluid contining bicarbonate, bile salts, cholesterol and bilirubin, synthesized by liver and stored in gallbladder. secretion control is by Cholecystokinin (CCK)

Front 47

bile salts

Back 47

synthesized in liver, cholesterol derivatives which facilitate digestion and absorption of fat, bicarbonate in bile neutralizes chyme to allow enzymes to work.

Front 48

sphincter of Oddi

Back 48

at the junction of the common bile duct and the small intestine, this sphincter prevents newly secreted bile from entering the small intestine if food is not present.

Front 49

hepatic portal vein

Back 49

takes venous blood to the liver from the entire GI tract.

Front 50

gallstones

Back 50

caused by the ability of the gallbaldder to concentrate bile through water removal (or if there is excessive bilirubin or cholesterol) this causes layers of cholesterol or bilirubin to be concentrated over time, forming large hard stones which can block the outflow of bile. (painful.)

Front 51

bilirubin

Back 51

secreted into the bile in a form which can not be absorbed by the intestine and is therefore disposed of. when the liver metabolizes hemoglobin molecules of destroyed red blood cells, bilirubin is one of the end products. excess bilirubin can cause jaundice: High levels of bile pigment are deposited in the mouth, nose and skin, causing yellowing discolouration. can occur because of health disorders such as sickle cell anemia, which causes too much bilirubin to be released to the blood, or impairment of the liver to remove bilirubin.

Front 52

jejunum

Back 52

most of the length of small intestine and therefore where most of the absorption occurs.

Front 53

ileum

Back 53

3rd part of the small intestine, empties into the large intestine at the ileocaecal sphincter. reabsorbs much of the bile salts, returned to the liver via the hepatic portal vein. absorbs B12.

Front 54

villi

Back 54

microscopic projections on surface of the folds of the small intestine, increases the surface area. layer of cells surrounding a central cavity with blood and lymph cells. gives intestine a HUGE absorptive surface.

Front 55

segmentation

Back 55

muscular contration that, with peristalsis, mixes intestinal contents with pancreatic juice and bile and moves contents towards the large intestine. <--PRIMARY purpose.

Front 56

gastroileal reflex

Back 56

increased contractile intestinal activity after eating - probably mediated by gastrin and parasympathetic nervous activity.

Front 57

amino acids

Back 57

small enough to be transported by "regular" cell transport methods, thes cross into the mucosal cells and then diffuse out into the blood.

Front 58

carbohydrates

Back 58

complex carbohydrates, tri and disaccharides, mostly broken down by salivary amylase, even in the stomach, then more in the intestine by pancreatic amylase. are broken into monosaccharides which can then cross into the mucosal cells.

Front 59

monosaccharides

Back 59

into mucous cells via secondary active transport. then diffuse out into blood.

Front 60

micelles

Back 60

small droplets of cholesterol and bile salts which are transported into the intestine from the liver & gallbladder. Free fatty acids enter micelles once broken down and are carried by them to the mucosal cells.

Front 61

emulsify

Back 61

break down large fat droplets into smaller fat droplets without changing the chemical composition of the fat.

Front 62

chylomicron

Back 62

carry monoglycerides and free fatty acids that have entered the mucosal cells via diffusion. Inside the ER of the mucosal cell, triglycerides are created from the monoglycerides and free fatty acids. these then have a protein coat them in the golgi apparatus, when they become a chylomicron. They are then packaged into secretory vessicles and are released into the lymph via the villus, as they are too large to go directly into the blood.

Front 63

lipase

Back 63

enzyme which reduces fat to free fatty acids and monoglycerides that can then enter the mucosal layer to be absorbed.

Front 64

lymphatic system

Back 64

system of lymph vessels that carry excess tissue fluid back to the circulatory system. Also aid in body defense.

Front 65

water

Back 65

small enough to enter the intestine and be absorbed without digestion, intestines can absorb ALL the water that you can drink. It diffuses easily, following the osmotic gradient.

Front 66

ions

Back 66

absorbed usually by facilitated diffusion or active transport (Na+ transports LOTS into mucosal layer.)

Front 67

Vitamin B12

Back 67

cannot be absorbed unless attached to intrinsic factor. Absorbed in terminal ileum. If not enough intrinsic factor, not enough B12 and person can become anaemic as B12 required for RBC erythropoesis.

Front 68

ileocecal valve

Back 68

valve through which unabsorbed chyme enters large intestine (prevents backflow) also called ileocecal sphincter.

Front 69

appendix

Back 69

small outpouching of cecum - blind pouch at proximal end of large intestine. No digestive function but does contain lymph nodes.

Front 70

haustra

Back 70

series of sac-like pouches that join together to form the colon, the interior mucosal layer of each haustrum is smooth. Haustra function not in absorption, but as a food storage site. Food is moved around and mixed in the haustra by a process called haustral shuffling, and is acted upon, being broken down by bacteria present within the haustra.

Front 71

bacteria

Back 71

400+ species live in the large intestine. Digest substances not easily digestible by pancreatic fluids (i.e. fibre and fats.) produce gas in the large intestine and synthesize K vitamins.

Front 72

K vitamins

Back 72

synthesized by bacteria of large intestine, also absorbed from food by small intestine. important in production of clotting factora, and to metabolism. Fat soluble vitamin.

Front 73

defecation

Back 73

rectal distension leads to the defecation reflex which is the relaxation of the anal sphincters which allows the feces to be ejected out of the anus.

Front 74

mass movements

Back 74

sustained contractions of the colon in which one section contracts at a time, to drive colonic contents towards the rectum.

Front 75

gastrocolic reflex

Back 75

occurring after a meal, this is the increased motility of the colon which increases colonic movement towards the rectum.

Front 76

external anal sphincter

Back 76

can be voluntarily relaxed to allow defecation.

Front 77

small intestine - structure facilitates function how?

Back 77

The small intestine is segmented, allowing for contractions which allow the chyme to be moved along. Internally, it is highly folded, allowing for a greatly increased surface area, and therefore greatly increased absorption of materials. Each mucosal fold inside the small intestine is covered with finger-like villi, which in turn are covered with microvilli. Each villi has an internal area of blood vessels and lymph cells, into which the food products can be immediately absorbed, transported, and any harmful foreign particles destroyed. The chemical makeup of the material in the small intestine reflects its main purpose of breaking down food into the smallest possible parts, and tehn absorbing those parts into the bloodstream. The bile duct and pancreatic ducts empty into the small intestine, and other enzymes and lipases accompany the bile salts and residual acids to enable digestion and eventual absorption within this structure.

Front 78

large intestine - structure facilitates function how?

Back 78

The large intestine is more suited to slow, prolonged contractions (haustral shuttling, mentioned earlier) which mix its contents. It does not contain many folds, like the small intestine, but rather is smooth on the inside, with not much surface area. This, as well as its shorter length reflect its main purpose as a food storage area. Additionally, digestion aids are not emptied into the large intestine. Rather, it contains bacteria which enable further breakdown of the feces. It functions mainly to drive its contents towards the rectum for defecation, however does absorb any remaining ions and water.

Front 79

breakdown of piece of bread from entry into mouth to absorption in small intestine.

Back 79

mouth -> secretion of salivary amylase and mechanical breakdown -> larynx-> esophagus -> stomach- continued digestion through salivary amylase -> intestine -> pancreatic amylase added
-> break down into starch, glycogen, disaccharides/trisaccharides. -> intestinal mucosal cells secrete enzymes which break down into monosaccharides, into mucosal cells via secondary active transport --> blood.

Front 80

pancreatic lipase vs. bile salts - function?

Back 80

digestion versus emulsification.

Bile salts arrive as micelles or droplets in the small intestine and function to emulsify fats, breaking the size of fat droplets down into smaller droplets, without altering the molecular structure of those fats.

pancreatic lipases act to actually digest the emulsified (smaller) droplets, changing their chemical make-up by making them into fatty acids and monoglycerides that are then small enough to be absorbed by the intestine.

Front 81

structural design of esophagus and stomach which ensure food only goes one way in GI system.

Back 81

MUSCLE - movement and structure:

sphincters - prohibit backflow
peristalsis and segmentation muscle movements move products FORWARD only.

Front 82

Gastrin secretion stimulated how?

Back 82

stomach distension and presence of proteins in stomach. Increases motility by stimulating parietal and chief cells of mucosa to secrete more HCl and pepsinogen.

Front 83

Three hormones of small intestine and their functions?

Back 83

secretin - stimulates pancreatic juice secretion

choleocystokinin - stimulates pancreatic amylase, causes gall contraction and sphincter of Oddi relaxation causing bile and bile salts to flow into small intestine.

gastric inhibitory peptide - secreted by small intestine into the bloodstream to inhibit gastric motility (causing chief and parietal cells to inhibit secretion of their enzymes.)

Front 84

exocrine substances of mouth, stomach, small intestine. source, functions and regulation.

Back 84

mouth: saliva and mucous in esophagus. lubricates food. nervous system control.
stomach: mucous, acid, pancreatic juice. protects stomach, breaks down food, kills bacteria.
intestine: mucous, pancreatic juices, bile, acids. lubricates and protects, neutralizes and digests, breaks fats down, breaks foods down.

Front 85

breakdown of proteins

Back 85

travel to the stomach where they are met with pepsin that has been secreted from the pancreas, which begins the protein breakdown. They become small enough that they can enter the mucosal cells, where they are further degraded by enzymes within those cells, to become small peptide chains. These are then transported through the mucosal cells by secondary active transport. They are further digested to amino acids by enzymes and can finally diffuse out to capillaries.

Front 86

breakdown of carbohydrates.

Back 86

digestion begins in the mouth by the enzymes there – salivary amylase. In the stomach, digestion continues via salivary amylase which is then joined by pancreatic amylase to continue carbohydrate breakdown from starches and glycogen (sugars) to di and tri-saccharides. These are then transported to the luminal cells in the intestinal membrane via secondary active transport, and after final break-down are transported as monosaccharides directly into the blood.

Front 87

breakdown of fats

Back 87

Stomach and intestinal peristalsis breaks fats into smaller droplets which are then further broken down (emulsified) by the bile salts from the liver and gall. Pancreatic lipases then break the fats down into monoglycerides and fatty acids. These can enter micelles, where they are transported by diffusion as they are soluble in the cell membrane. They are resynthesized there into triglycerides in the Endoplasmic reticulum, are coated with a protein layer by the golgi body, (now called chylomicrons) and enter lymph vessels where they are returned to blood, as they’re too large at this point to move directly into the blood through the vessels.