A&P Digestive System

ingestion

eating and swallowing food

mechanical processing

physically breaking food apart

chemical digestion

breaking chemical bonds

motility

alternating muscle contractions

digestive tract organs

organs through which food material passes through

accessory organs

organs which does not have food pass through them but produces enzymes

oral cavity, esophagus, stomach, intestines

digestive tract organs include:

sakivary glands, liver, gall bladder, pancreas

accessory organs include:

mastication

chewing food

enzymes; break chemical bonds

water helps mix food with ______ and helps _________

maintain neutral mouth pH

mucus and buffers help…

Ig-A antibodies

immunogobins present in saliva

starch

salivary amylase breaks down ________

water, mucus/buffers, immunoglobins, amylase

4 components of saliva

neutral

What pH can amylase work in?

maltose

what does amylase break starch down into?

bolus

chewed, partially digested food

deglutition

swallowing

rises up to prevent bolus from entering nasal cavity

what happens to the soft palate when swallowing?

folds downward to prevent the bolus from entering the trachea and larynx

what happens to the epiglottis when swallowing?

esophagus

muscular tube that extends from the pharynx to the stomach

peristalsis

muscular contractions that move the bolus towards the stomach

esophagel hiatus

opening in the diaphragm that allows the esophagus to pass through from the thoracic cavity into the abdominal cavity

lower esophageal sphincter

band of smooth muscle between esophagus and stomach

lower esophageal sphincter

opens to allow the bolus in the esophagus to enter stomach and closes to prevent acidic material in the stomach from reentering the esophagus

rugae

folds of the inner lining of the stomach that allow the stomach to expand with food

mechanical digestion

mixing and churning due to smooth muscle contractions

chyme

soupy mixture of stomach secretions and further digestive bolus

duodenum

where does chyme move from the stomach to?

duodenum

first part of the small intestine

pyloric sphincter

band of smooth muscle between the stomach and the duodenum that opens and closes to regulate the movement of chyme into the duodenum

Absorption of nutrients

What does mucus inhibit?

pepsinogen

what do chief cells secrete?

intrinsic factor and HCl

what do parietal cells secrete?

intrinsic factor

a transporter needed for the absorption of vitamin B12

turn pepsinogen into pepsin

What does HCl do?

pepsin

active enzyme that breaks down proteins into polypeptides

small intestine

location of most chemical digestion and absorption

surface area

features in the small intestine increase what?

plicae

circular folds of the inner lining of the small intestine

chyme

slow down the movement of chyme

villi

fingerlike projections covering the plicae

blood capillaries

where does the absorption of glucose and amino acids take place in villi?

lacteals

in villi and absorbs fats and transports fats to the bloodstream

microvilli

microscopic extensions on the surface of epithelial cells of villi that appear as fuzzy edges

brush border enzymes

enzymes that are embedded in the cell membrane of epithelial cells that complete chemical digestion right before absorption

duodenim

first part of the small intestine

acidic chyme

the duodenum recieves _______ from the stomach

bile

the duodenum recieves _______ from the liver and or gallbladder

enzymes; buffers

the duodenum recieves _______ and __________ from the pancreas

jejunum

middle part of the small intestine

jejunum

place where most chemical digestion and absorption occurs in the small intestine

ileum

last part of the small intestine

large intestine

what is ileum connected to?

sodium bicarbonate

buffer that neutralizes acids in the duodenum from the stomach

pancreatic enzymes

aid in the chemical digestion ocuring in the lumen of the small intestine

pancreatic amylase

enzyme from the pancreas that breaks down starch into maltose

pancreatic lipase

enzyme from the pancreas that breaks lipids down into glycerol and fatty acids

pancreatic protease

enzyme from the pancreas that breaks down proteins and polypeptides

trypsin, chymotrypsin, carboxypeptidase

list the three pancreatic protease

liver

produces bile

gall bladder

stores and secretes bile into the duodenum

bile

emulsifies fats which increases the surface area for the action of pancreatic lipase

liver

synthesizes and releases blood plasma proteins

liver

stores glucose in the form of glycogen

liver

break down and eliminates metabolic wastes and toxins

liver

site of phagocytosis of damaged RBCs and bacteria

liver

synthesizes cholesterol

cells lining

where do brush border enzymes finish the breaking down of nutrients in the small intestine?

small intestine

where are brush border enzymes made?

peptidase

brush border enzymes that breaks down peptides into amino acids

maltose

brush border enzymes that breaks down maltose into two glucose molecules

sucrase

brush border enzymes that breaks down sucrose into a glucose and fructose molecule

lactase

brush border enzymes that breaks down lactose into glucose and galactose

ileum

cecum is connected to the_____

ileocecal valve

regulates the movement of chyme from the ileum into the cecum