unit 15 learning objectives

mouth

alimentary canal (GI tract)

pharynx

alimentary canal (GI tract)

esophagus

alimentary canal (GI tract)

stomach

alimentary canal (GI tract)

small and large intestine

alimentary canal (GI tract)

salivary glands

accessory organs

pancreas

accessory organs

liver

accessory organs

gall bladder

accessory organs

mouth function

mechanically breaks down food and begins chemical digestion of carbohydrates

pharynx function

connects mouth w/ esophagus

esophagus function

peristalis pushes food to stomach

stomach function

secretes acid and enzymes that mix with food to begin enzymatic digestion of proteins

small intestine function

mixes food with bile and pancreatic juice, final enxyatic breakdown of food and main site of nutrient absorption

large intestine function

absorbs water and electrolytes to form feces

salivary glands function

secretes saliva which contains enzymes that initiate breakdown of carbohydrates

liver function

produces bile which emulsifies fat

gallbladder function

stores bile and introduces it into small intestine

pancreas

produces and secretes pancreatic juice containing digestive enzymes and bicarbonate ions into small intestine

mucosa

innermost layer of alimentary canal which contains simple columnar epithelium that protects tissue beneath itself, secretes into lumen and absorbs substances from the diet

submucosa

layer beneath mucosa that contains loose connective tissue and blood vessels that nourishes surrounding tissue and carry away absorbed materials

muscularis

layer beneath submucosa with circular and longitudinal smooth muscle that provides movement of the tube

serosa

outermost layer that compromises the visceral peritoneum and moistens and lubricates the tubes outer surface

parasympathetic

promotes motility and enzyme secretion through the vagus nerve

sympathetic

inhibits mixing and propelling movements but stimulates contraction of sphincter muscles

peristalsis

rhythmic waves of muscular contraction in the walls of certain tubular organs

segmentation(mixing)

alternating contraction and relaxation of circular muscle fibers that mix intestinal contents

lips

vestibule

hard palate

soft palate

cheek function

lateral walls of mouth lined with stratified squamous columnar

lips function

contain skeletal muscle and sensory receptors that judge temperature and texture of foods

tongue function

helps to mix food together

soft palate function

helps prevent food from entering nasal cavity

lingual tonsils

palatine tonsils

pharyngeal tonsils

saliva function

moistens food particles which helps bind them and it begins chemical digestion of carbohydrates

parotid gland

subllingual gland

submandibular gland

salivary glands secrete

amylase that breaks down carbohydrates

stomach secretes

pepsinogen and hydrochloric acid (inactive) and pepsin (active) that breaks down proteins

pancreas secretes

amylase, lipase which breaks down lipids

(pancreas) prolease

breaks down proteins

(pancreas) nuclease

breaks down nucleic acids

(pancreas) trysinogen

breaks down proteins

small intestine secretes

peptidose which breaks down proteins

nasopharynx

oropharhynx

laryngopharynx

first stage of swallowing

(voluntary) food is mixed w/ saliva and tongue rolls it into a bolus and forces it down the oropharynx

second stage of swallowing

food stimulates receptors around the pharyngeal opening and soft palate prevents food from entering nasal cavity, then epiglottis closes off the trachea, then tongue presses against soft palate to close off oral and nasal cavity, then longitudinal muscles pulls the pharynx toward food, the lower inferior constrictor muscles relax and open esophagus, the superior constrictor muscles contract and stimulate peristaltic wave that forces food into the esophagus.

third stage of swallowing

peristalsis transports food from esophagus to stomach

what happens to respiration during swallowing?

momentarily breathing is paused

esophageal hiatus which is the opening in the diaphragm that the esophagus passes through

cardiac region of stomach

fundic region of stomach

body region of stomach

pyloric region of stomach

pyloric sphincter

lower esophageal function

ring of smooth muscle at the end of the esophagus that joins the stomach and prevents food from re-entering the esophagus when the stomach contracts

greater omentum which is a double fold of peritoneal membrane that seals of the peritoneal cavity to prevent infection

mesentery which suspends and attaches jejunum and ileum to the posterior abdominal wall

HCI (hydrochloric acid) function in stomach

provides the acid enviornments needed for production and action of pepsin

mucus function in the stomach

provides alkaline mucus that protects the inner surface from HCI and enzymes

pancreas

pancreatic and common bile duct relation

joined together by the hepatopancreatic ampulla which surrounds the sphincter that controls movement of pancreatic juice and bile to the small intestine

pancreas function

produces glycogen and insulin

name and function

liver and it detoxifies blood, produces and secretes bile, stores glycogen,vitamins A, D, B12, iron and blood

gallbladder anatomy

pear shaped sac in a depression on the inferior surface of the liver

gallbladder functions

stores bile b/w meals and concentrates it by reabsorbing water, when it contracts it releases bile into small intestine through cystic and common bile ducts

gallbladder process step 1

chyme w/ fat enters the duodenum

gallbladder process step 2

cells of intestinal mucosa secrete hormones chloecystokinin(cck) into the bloodstream

gallbladder process step 3

cck stimulates the muscular layer of the gallbladder wall to contract

gallbladder process step 4

bile passes down cystic duct and bile duct to the duodenum

gallbladder process step 5

hepatopancreatic sphincter relaxes and bile enters the duodenum

duodenum

duodenum function

connects stomach and jejunum, site of nutrient absorption and chemical digestion

jejunum

jejunum function

b/w duodenum and the ileum and rapidly absorbs nutrients, water,and electrolytes from chyme

ileum

ileum function

b/w the jejunum and the cecum

movement of small intestine

mixing occurs through segmentation where smaller regions contract at different times moving chyme back and fourth breaking food down into smaller pieces

peristaltic waves

propel chyme down small intestine

how does the ileocecal sphincter open?

gastroileal reflex relaxes the ileocecal sphincter

cecum

appendix

ascending colon

transverse colon

descending colon

sigmoid colon

rectum

anal canal

what does the large intestine absorb/vitamins synthesized?

water, electrolytes, vitamins k, b12, thiamine, ribofalavin,

valsalva maneuver

a breathing technique performed by attempting to exhale forcibly against a closed airway (pinched nose/closed mouth), similar to bearing down for a bowel movement, for 10–15 seconds