Digestive system

epithelium lining opening/exit

stratified squamous

epithelium lining beyond esophagus and most part of the tract

simple columnar

Which layers of the stomach wall form rugae?

The mucosa and submucosa

which plexus supplies nerve impulses to glands in the submucosa?

Submucosal (meissner's) plexus

which plexus controls speed and rate of contraction in stomach?

Myenteric nerve plexus

what is the serosa called for the esophagus?

adventitia

how many layers of muscle are lining the stomach?

3 (longitudinal, circular, and oblique layer)

what is the sheet of peritoneum extending from the posterior wall to the intestines that act as an anchor?

mesentery

what is the uppermost region of the stomach?

fundus

what is the middle region of the stomach?

body

what is the sphincter connecting the stomach to the small intestine called?

pyloric sphincter

what is the sphincter connecting the esophagus to the stomach called?

gastroesophageal sphincter

what is the term for swallowing?

deglutition

what is the oblique layers purpose in the stomach?

maintain shape & create churning action

what is the term for chewing?

mastication

what makes up the muscularis externa of the esophagus?

1/3 skeletal muscle at beginning; 2/3 smooth muscle

which part of the stomach produces gastric juice?

fundus & body

which part produces the gastrin hormone?

pyloric

which salivary gland produces the most amylase?

Parotid; biggest gland

which salivary gland produces less amylase, more mucin?

submandibular gland

which salivary gland produces mostly mucin?

sublingual gland

what is the term for food after it has been chewed and mixed with saliva?

bolus

which enzyme breaks down carbohydrates in the salivary glands?

salivary amylase (ptyalin)

what is the entrance to the stomach called where food first enters?

cardia

what are the glands in the stomach called?

gastric pits

what are gastric pits made of?

simple columnar with goblet cells for mucous layer for protection

neck cells

secrete mucus

parietal cells

secrete HCl and intrinsic factor (B-12 ABSORPTION)

*fundus & body

chief cells

secret pepsinogen, prorennin, & gastric lipase

*fundus & body

pepsin

hci activated; digests proteins

rennin

hci activates; curdles milk

*only active in babies

gastric lipase

milk fats

*only active in babies

enteroendocrine cells (g cells)

secret gastrin into bloodstream; pyloric region

gastrin

hormone secreted in the stomach that stimulates secretion of HCl and increases gastric motility

which phase is prior to food entering; stimulating vagus to start making gastric juice?

cephalic phase

which phase begins stomach distension & gastrin release

gastric phase

intestinal phase

Stage in which the duodenum responds to arriving chyme and moderates gastric activity through hormones and nervous reflexes

enterogastrones

Secretin and cholecystokinin (CCK) are gastrin-inhibiting hormones released by small intestine to inhibit gastrin secretion & movement

enterogastric reflex

causes peristalsis in the stomach to decrease and less chyme leaves the stomach

ulcer

90% cause by h. pylori bacteria

sore/erosion in lining of the stomach

what are the big folds of mucosa and submucosa that make chyme slowly move through?

plicae circularis

what are the mucosa tiny folds in the small intestine called?

villi

lacteal

a lymph tubule located in the villus that absorbs fatty acids

intestinal crypt

the stem cell niche for intestinal epithelial cells

microvilli

projections that increase the cell's surface area; brush border enzymes here

amylase

breaks down carbs in small intestine

nucleases

breaks down dna & rna (nucleic acids) in small intestine

proteases

breaks down protein

enterokinase

activates trypsinogen (from the pancreas) to trypsin; a protease for breaking down protein

duodenum

-first part of the small intestine

-brunners gland (bicarbonate to balance pH)

-liver, pancreas, & gallbladder release enzymes here

primary movement of chyme/kneading action

segmentation

jejunum

most villi/most digestion occurs here

2nd part of intestine

ileum

-the last and longest portion of the small intestine

-peyer's patches (lymphatic tissue in wall)

which valve connects the large intestine to the small intestine?

ileocecal valve (sphincter)

peyer's patches

collections of lymphatic tissue found in the submucosa of the small intestine

appendix

blind pouch hanging from the cecum

entrance of large intestine

cecum

acinar cells

secrete digestive enzymes that enter the pancreatic duct to go to the duodenum

lobular duct cells

found in pancreas; secrete bicarbonate and water

how many lobes does the liver have?

4 right/left; caudate/quadrate

gallbladder

inferior edge of liver, stores and concentrates bile

hepatocytes

liver cells in lobules; produce bile, absorb and secrete nutrients like glucose, and secrete plasma proteins

bile salts

emulsify fats & form micelles

micelles

tiny spherical complexes of emulsified fat; contain bile salts wrapping the the products of lipid digestion to pass through mucous membranes

chylomicrons

fat droplets covered in protein that diffuse into capillaries in small intestine (lacteal)

cystic duct

Duct leading from the gallbladder to the common bile duct; carries bile

hepatic duct

passageway for bile from the liver

what is the term used to describe the huge/strong contraction of the large intestine?

mass movement

sections of the large intestine

cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum

tenia coli

3 bands of smooth muscle in the muscularis externa forming pouches called haustra

what are the bundles of fat that function as energy storage on the large intestine sticking to serosa called?

epiploic appendages

varicose veins in anal canal

hemorrhoids

internal sphincter of anal canal

smooth muscle, involuntary control

external sphincter of anal canal

skeletal muscle, voluntary

defecation reflex

activated by stretch receptors stimulated by filling of the rectum

absorption phase

regulated by insulin; mostly in small intestine; lasts up to 4 hours after eating

glucose

to liver by portal vein; primary source of atp; glycogen 10% (liver/skel. muscle) & triglyceride into adipose 40% storage (liver)

amine

-villi capillary to portal vein to build proteins (liver)

-triglycerides

fats

chylomicron > absorbed into lacteal > into blood > subclavian vein > deposited into adipose for storage

insulin

stimulus = high blood glucose; made from beta cells in pancreas

-enhances glucose conversion to ATP

-glycogen production & triglycerides for fat storage

-increase active transport into tissue cells to increase protein sytnhesis

beta cells_

secrete insulin (pancreas)

alpha cells

secrete glucagon (secret pancreas)

glucagon

produced by alpha cells in pancreas; stimulus = low blood glucose

triggers lipolysis to increase plasma fatty acid & glycogenolysis/gluconeogenesis for brain

post absorption phase

regulated by glucagon & epinephrine

gluconeogenesis

The formation of glucose from noncarbohydrate sources, such as amino acids.

glycogenolysis

breakdown of glycogen to glucose (for the brain to use as energy)

adipose lipolysis

break apart glycerol for gluconeogenesis (mainly liver) & fatty acid tail for most of the direct atp production ++++ liver turns ketogenesis for ketone bodies into bloodstream

epinephrine

stimulus low blood sugar

hypothalamus > adrenal medulla

triggers lipolysis & glycogenolysis

what happens during prolonged fasting?

fat is the primary fuel source; gluconeogenesis for the brain from the liver (can result in extensive muscle wasting)

~due to low blood sugar stress: glucocorticoids and growth hormone also trigger

what does glucocorticoids do for blood sugar?

increase blood sugar by breaking down fats & proteins (gluconeogenesis)

*suppresses immune system

what does the growth hormone do for blood sugar?

-stimulus: low blood sugar, day/night rhythm

-direct action: increase fat breakdown to increase blood sugar/energy source

-indirection action: targets liver & other tissue to insulin like growth factors (skeletal, cartilage, protein synthesis)