Digestive System Study Guide Flashcards
Hard outer protective layer of the teeth
Enamel
Bone-like material that surrounds the pulp
Dentin
Houses the nerves and blood vessels of teeth
Pulp
Anchor the teeth to the jawbone
Periodontal membranes
Taste food; aids in the mechanical digestion of food; pushes bolus to pharynx
Tongue: Taste buds
Closes off nasopharynx when swallowing
Soft palate
Covers glottis during swallowing to prevent choking
Epiglottis
Space for the food bolus to travel through
Lumen
Nonkeratinized stratified squamous epithelium provides a protective lining
Mucosa
Contains blood vessels, lymphatic vessels, nerves, and glands; the glands secrete mucus into the lumen to aid in the transport of food
submucosa
Moves the food via peristalsis
Muscularis
(two layers of smooth muscle)
Relaxes to allow the bolus into the stomach and then contracts to close; prevents acid from entering the esophagus
Lower esophageal sphincter
Produces gastric juice composed of pepsinogen and hydrochloric acid (pH 2; kills bacteria and converts pepsinogen to pepsin); the semiliquid food is now called chyme
Mucosa
(gastric pits)
Mechanical digestion of food via peristalsis
Muscularis
(three layers of smooth muscle)
Controls the movement of chyme into the small intestine
Pyloric Sphincter
Produces brush border enzymes (e.g., maltase, sucrase, lactase, peptidases, and lipases) for chemical digestion of the chyme; absorbs nutrients; goblet cells produce mucus
Mucosa
(simple columnar epithelium forms folds called villi; cells contain microvilli)
Absorbs and transports chylomicrons (contains fat in the form of triglycerides)
Villus
Absorb and transport glucose and amino acids
Villus: Blood capillaries
Receives bile from liver and gallbladder and pancreatic juice from pancreas for chemical digestion of the chyme; absorbs nutrients
Duodenum
(the first part of the small intestine)
Produce bile that contains bile salts, bicarbonate ions (neutralizes the acidic chyme), and bilirubin (makes bile green)
Liver
Collects the bile produced by the hepatocytes
Bile canaliculi
Collects the bile from the bile canaliculi
bile duct
Brings oxygenated blood to the liver
Hepatic artery
Transports nutrient-rich blood from the GI tract to the liver
Hepatic portal vein
Stores bile produced by the liver; releases stored bile into the common bile duct
Gallbladder
Secretes pancreatic juice (bicarbonate ions (neutralize the acidic chyme) and digestive enzymes (e.g., pancreatic amylase, trypsin, and lipase)) into the small intestine via the pancreatic duct; secretes insulin into the bloodstream so cells can utilize glucose
Pancreas
Receives contents from the small intestine; has a projection called the appendix
cecum
Absorbs vitamins, such as B vitamins and vitamin K, produced by the intestinal flora; absorbs water
Colon
(ascending, transverse, descending)
Stretching of the rectal wall initiates nerve impulses to the spinal cord, which results in the rectal muscles contracting for defection
Rectum
Stool/feces/poop exits; the external anal sphincter is made of skeletal muscle so we can control defecation
anus
What enzymes are needed to break down carbs?
amylase
maltase
lactase
What enzymes are needed to break down proteins?
pepsin
trypsin
peptidase
What enzymes are needed to break down fats?
bile salts
lipase
What horomone does this describe?
when chyme enters the duodenum, the duodenum secretes this to stimulate the liver to produce bile and the pancreas to produce pancreatic juice; the bicarbonate ions neutralize the acidic chyme
Secretin
What horomone does this describe?
secreted by the stomach in response to a meal rich in protein, which causes the stomach to produce more gastric juice (contains hydrochloric acid and pepsin)
Gastrin
What horomone does this describe?
a meal rich in proteins and fats stimulates the duodenum to secrete this, which causes the liver to increase bile production, the gallbladder to contract and release stored bile, and the pancreas to secrete pancreatic juice
CCK
needed for nerve impulses, muscle contraction, and blood clotting
Calcium
converted to calcitriol to promote the absorption of calcium by the intestines; helps prevent osteoporosis and rickets
Vitamin D
necessary for blood volume, nerve impulses, and muscle contraction; too much can cause or worsen hypertension
Sodium
allows erythrocytes to transport oxygen and carbon dioxide; deficiency can result in anemia
Iron
is required for making collagen; prevents scurvy
Vitamin C
greatly decreases the risk of having a baby with spina bifida if taken by the mother before and during pregnancy
Folate (Vit. B9)
