Digestive System Flashcards
general characteristics of the digestive system
extends? what is involved? aka? how are muscles involved?
extends about 5-7 meters from mouth to anus
Gastrointestinal (GI) Tract
-aka alimentary canal
muscles are in sustained contraction along tract
Digestive System Basic Processes (6)
1) Ingestion
2) Secretion (enzymes break down food)
3) Mixing & Propulsion (why stomach gurgles (peristalsis))
4) Digestion (takes place mainly in small intestine)
5) Absorption (also in small intestine, why it’s so long)
6) Defecation (pooping)
Peritoneum
def? parts? (4)
largest serous membrane in body in abdominal cavity
- mesentary
- parietal peritoneum
- visceral peritoneum
- peritoneal cavity
Mesentary
def?
binds small intestine to abdominal wall
Parietal Peritoneum
def?
lines wall of abdominopelvic cavity
Visceral Peritoneum
def?
covers some organs in digestive system
Peritoneal Cavity
location? filled w/?
btwn 2 layers
filled w/ serous fluid
Accessory Organs of the Digestive System
what are they? all connected by…?
Pancreas Liver Gallbladder Salivary Glands ALL connected by ducts
Pancreas
also what? produces how much per day? duct involved? function?
also an endocrine gland
produces 1200-1500 mL/day
pancreatic duct connects w/ small intestine
FUNCTION: secretes pancreatic juice
what are all the enzymes/pancreatic juices the pancreas produces? what do they help with? (7)
pancreatic amylase- carbohydrate digestion
pancreatic lipase- fat digestion
trypsin- protein digestion
nuclease- break down nucleic acids
also: water, sodium, bicarbonate (neutralize intestine, base)
Liver
known as? description? functions in general? (5)
largest internal organ divided into left & right lobes functions: 1.maintains 2.storage 3.blood filteration 4.detoxification 5.produces bile
Liver Function
Maintains what?
1) Maintains carbohydrate, lipid, & protein metabolisms
Liver Function
storage of what?
2) Storage- glycogen, iron, & vitamin A, D, K, & B12
Liver Function
blood filteration of what?
3) Blood filteration- phagocytizes RBC, WBC, some bacteria
Liver Function
Detoxification of what?
4) Detoxification of blood (alcohol & drugs)
Liver Function
produces what?
5) Produces Bile (bile salts)
Bile
description? how much produced per day? includes (4)? function?
Yellowish-green liquid secreted by hepatic cells (liver) 800-1000mL/day produced Includes: -bile salts -cholesterol -electrolytes (ions) -water aid in fat digestion (breaks fat into smaller globules)
Gallbladder
function? duct involved?
Function: -stores bile
-releases bile into small intestine through common bile duct
which organ stores bile and which makes it?
gallbladder stores bile
liver makes bile
Small Intestine
description? contains? purpose of these?
18-20 ft. long, 1 in. diameter
contains circular folds- increase surface area for absorption
Small Intestine
Functions? (4)
1) Receives secretions from pancreas & liver (like enzymes & bile)
2) Completes digestion of nutrients in chyme (using enzymes & bile)
3) Absorption of nutrients & water from digestion
4) Transports remaining residue to large intestine
Small Intestine Regions (3)
Duodenum
Jejunum
Ileum
Small Intestine Region- DUODENUM
description/length?
10 in. long, (shortest & fixed portion) (doesn’t move!)
Small Intestine Region-JEJUNUM
description/length? known to be?
Larger & thicker region
3 ft. long
More active in absorption than ileum
(really folded)
Small Intestine Region-ILEUM
location? length? contains (2)?
Before large intestine
6 ft. long
Contains more lymph vessels, nerves, & blood vessels (absorption as well)
Ileocecal sphincter- joins small & large intestine
Small Intestine Structures (2)
Intestinal Villi
Intestinal Glands
Small Intestine Structure - INTESTINAL VILLI
description? what other structure is involved? function of them?
fingerlike projections of mucosa covered w/ MICROVILLI -absorptive cells w/ enzymes in them Function: increase surface area of intestine for absorption -contains blood & lymph vessels
Small Intestine Structure - INTESTINAL VILLI
function? contains?
Function: increase surface area of intestine for absorption
-contains blood & lymph vessels
Small Intestine Structure - INTESTINAL GLANDS
location? function? how often does it occur? helps what?
btwn bases of villi
Function: secrete large volume of intestinal juice (water & mucous)
-secretes 1-2 L/day
-helps villi absorb digestive products
intestinal juice is made up of what? (2)
water & mucous
constipated w/o water
Intestinal Enzymes
secreted by what?
secreted by epithelial cells in villi
Intestinal Enzymes - PEPTIDASE
what does it do?
breaks peptides into amino acids
Intestinal Enzymes - Sucrase, Maltase, Lactase
what does it do?
breaks down disaccharides into monosaccharides
break down sugar enzymes, lactase- milk sugar
Intestinal Enzymes - Intestinal Lipase
what does it do?
splits fats into fatty acids & glycerol
Large Intestine
length/description? contains what?
5 ft. long, 2.5 cm. in diameter - no villi
Haustra
Large Intestine
Functions? (4)
1) Haustral churning & peristalsis to move contents into rectum
2) Absorbs some water, electrolytes, & vitamins
3) Forms & stores feces
4) Defecating- emptying rectum
Large Intestine- HAUSTRA
def?
pouches of colon caused by contraction of colon muscles
Parts of Large Intestine
what are they (5)?
1) Cecum
2) Colon
3) Rectum
4) Anal Canal
5) Anus
Parts of Large Intestine - CECUM
location? description? what’s attached @ the end of it?
beginning of large intestine
pouch-like
appendix attached @ end
Parts of Large Intestine - COLON
4 parts & location? (another name for the colon is..?)
ascending- right side transverse- longest, most moveable descending- left side sigmoid- S shaped curve @ end (another name for large intestine)
Parts of Large Intestine - Anal Canal
length?
8 in. long
Parts of Large Intestine - Anus
def? aided by?
opening to outside of body
-aided by: Internal & External anal sphincters
what color is the gallbladder?
green
key word for the digestive system?
peri
Final Digestion
what is it? what is produces and what is fermented? what’s released?
Activity of bacteria called intestinal flora
- produces some B & K vitamins
- ferment remaining carbs
- release hydrogen, carbon dioxide, & methane gases
Feces
def? contains (6)?
product of chyme after 3-10 hrs in colon after water absorption
contains:
-undigested food, water, electrolytes, mucus, shed intestinal cells, bacteria
Mouth is aka?
Oral Cavity
Mouth (Oral Cavity)
Functions (2)? what is involved in each? purpose of them?
Function: 1. Mainly mechanical digestion (starts mechanical)
- tongue & teeth reduce food to soft, flexible mass- BOLUS
2. Begins chemical digestion - salivary amylase in saliva
- breaks down carbs (starch) into disaccharides
Salivary Glands
Function:
Secrete saliva (99.5% water, 0.5% solutes)
-secretion increases w/ food
Salivary Glands
what are the 3 sets/pairs?
Parotid glands
Submandibular glands
Sublingual glands
Salivary Glands- PAROTID GLANDS
location? description?
largest, anterior to ears
watery fluid w/ amylase
Salivary Glands- SUBMANDIBULAR GLANDS
location? description?
floor of mouth
thicker fluid w/ mucous
Salivary Glands- SUBLINGUAL GLANDS
location? description?
smallest, beneath tongue
thickest fluid
Pharynx
function? connects what? contains?
Function: passageway for food (& air)
connects nasal & oral cavities w/ larynx and esophagus
contains sense receptors for swallowing
Esophagus
length? functions (2)? contains?
about 25 cm. long
Function: -move food -moisten & lubricate food (mucous)
contains esophageal sphincter (aka cardiac sphincter)
Esophagus- esophageal sphincter (aka cardiac sphincter)
btwn what? muscle fibers description? what does the sphincter prevent?
btwn esophagus and stomach
group of circular muscle fibers that remain contracted
prevents regurgitation into esophagus
Deglutition (Swallowing)
bolus movement/location? what happens? (2 different locations of bolus description)
Bolus moves from mouth to pharynx
-triggers sense receptors in medulla oblongata and pons to swallow
Bolus moves from pharynx to esophagus
-peristalsis occurs
Peristalsis
what is it? describe (2)
coordinated contractions of muscularis layer of GI tract
moves food through GI tract
(wave-like motion of muscle contraction, all along GI tract, arhythmic contractions, constant)
Stomach
shape? capacity/length? size when empty? inner lining thick folds are called what? can they be seen?
J-shaped 1 L capacity, 20-30 cm. long Empty- size of large sausage Inner lining thick folds called rugae -disappear in full stomach
Stomach
Functions (4)
moves food w/ gastric juice (mix w/ food to break down)
initiates digestion of proteins
carries on limited absorption
bolus converted to chyme (paste bc mixed w/ gastric juice)
-liquid
Parts of the stomach (4 regions)
Cardia region
Fundus region
Body region
Pyloric region
Parts of the stomach- Cardia Region
location?
closest to esophagus
Parts of the stomach- Fundus Region
description (2)?
temporary storage area
sometimes fills w/ swallowed air
Parts of the stomach- Body Region
location?
Central portion
Parts of the stomach- Pyloric Region
location? becomes what? contains? functions of what is contains (2)?
Narrow portion at bottom Becomes the pyloric canal close to small intestine Pyloric sphincter -btwn stomach and small intestine -controls gastric emptying
Gastric juice
Contains: -pepsin (enzyme), mucous, HCL
-produce 2000-3000 mL per day
Function of Gastric Juice
break down proteins
Gastric Juice- Gastric Glands
what kind of cells does it contain? what are the 3 types?
contains 3 types of secretory cells
- mucous cell
- chief cells
- parietal cells
Gastric Glands- Mucous cell
secretes? why?
secrete mucous, protect stomach lining
Gastric Glands- Chief cells
secretes? why?
secretes pepsinogen that forms into enzyme pepsin- break down proteins
Gastric Glands- Parietal cells
secretes? why?
secretes HCl solution & intrinsic factor (aids in vitamin B12 absorption) (helps body absorb things)
sphincters in stomach… what is at beginning and what’s at the end?
beginning- cardiac
end- pyloric
general stomach characteristics
rate of emptying depends on what?
rate of emptying depends on type of food and fluidity of chyme
general stomach characteristics
what passes through quickly? longest? what happens when you’re more hungry?
liquids, proteins, and carbs pass through quickly (bc already being broken down by enzymes)
fatty foods- 3-6 hrs (take longest)
more hungry- more gastric juice secreted
how many layers does the GI tract have? what are they?
4 layers of the GI tract: serosa muscularis submucosa mucosa
Submucosa
type of tissue & purpose of it? contains and what do they do? what controls it? what else plays a role?
connective tissue that binds mucosa to muscularis
- contains: glands
- Neuronal networks from ENS and ANS control secretions into GI tract
- Blood & lymphatic vessels absorb food molecules
- Glands in submucosa secrete substances into GI tract
Muscularis
aka/what does it produce? def? type of muscle & purpose of it? contains different muscle like? controlled by?
(peristalsis) (muscularis produces movement)
thick layer of muscle (mostly smooth, but part skeletal in esophagus and anal sphincter muscles) that break down food, mix it, and move it through GI tract (smooth-intestines & stomach, skeletal- upper GI mouth, pharynx, upper eso.)
-inner sheet of circular muscle
-outer layer of longitudinal muscle
-ENS neurons control frequency and strength of muscle contractions
Mucosa
def? contains (2)? layers (4)?
Inner lining of digestive tract (SECRETES MUCOUS)
- contains: digestive enzyme secreting glands & mucous
- Epithelium -absorbs substances
- Lamina propria -is connective tissue
- Muscularis mucosae -thin layer of smooth muscle that creates folds in mucosa, which increases absorptive surface area.
- Lymphatic nodules -protect against pathogens
Serosa
aka? consists of (2)? function/purpose?
(Peritoneum)
outermost layer, which consists of:
connective tissue & epithelium
serosa secretes a watery fluid (serous) that lubricates GI tract, allowing it to slide against other organs
(In the stomach) Surface Mucous Cell
what does it secrete?
secretes mucus
(In the stomach) Mucous Neck Cell
what does it secrete?
secretes mucus
(In the stomach) Parietal Cell
what does it secrete?
secretes hydrochloric acid & intrinsic factor
(In the stomach) Chief Cell
what does it secrete?
secretes pepsinogen and gastric lipase
(In the stomach) Enteroendocrine Cell
what does it secrete?
secretes hormone gastrin
(In the Small Intestine) Absorptive Cell
function?
absorbs nutrients
(In the Small Intestine) Goblet Cell
function?
secretes mucus
(In the Small Intestine) Enteroendocrine Cell
function?
secretes hormones secretin or cholecystokinin
(In the Small Intestine) Paneth Cell
function?
secretes lysozyme and is capable of phagocytosis
