Lect. 17/18 - Digestive system Part 2 (from liver) Flashcards
Heaviest gland in the body
Liver
Second largest organ in the body
liver
what divides the right and left lobes of the liver
falciform ligament
name the 4 lobes of hte liver
right, left, quadrate, caudate
functional cells of the liver
hepatocytes
contain fixed phagocytes, which destroy worn out leukocytes, RBC, bacteria and other foreign matter from the GI tract venous blood
sinusoids
bile is secreted by what
hepatocytes
the bile enters the ___ ___ which empty into small ___ ___
bile canaliculi, bile ductules
the ductules pass bile into ___ ___
bile ducts
eventually merge into R/L __ ___
hepatic ducts
R/L hepatic ducts unite to form the ___ ___ ___
common hepatic duct
common hepatic duct joins the ___ and they form the ___ __ __
cystic duct, common bile duct
ligaments of the liver (3)
falciform ligament
ligamentum teres (round)
R/L coronary ligaments
is a remnant of the umbilical vein of the fetus
ligamentum teres (round ligament)
suspends the liver from the diaphragm
R/L coronary ligaments
blood supply of the liver
hepatic artery and hepatic portal vein
what is the portal triad
hepatic portal vein, hepatic artery and bile duct
liver - parasympathetic innervation
vagus nerve
liver - sympathetic innervation
celiac ganglia
pear shaped sac located in a depression on the posterior surface of the liver
Gall bladder
3 parts of the gall bladder
fundus
body
neck
function of the gallbladder
store and concentrate bile until it is needed by the S.I
blood supply of gall bladder
cystic artery
innervation of gallbladder
branches of the celiac plexus and vagus nerve
plays a key role in emulsification
bile salts
between meals, the __ ___ ___ closes off and bile flows into the gallbladder for storage
greater duodenal papillae
after a meal, _____ impulses along the vagus nerve stimulate the liver to ___ bile production
parasympathetic
increase
fatty acids and amino-acids in chyme stimulate duodenal enteroendocrine cells to secrete ____ in the blood
cholecystokinin (CCK)
role of CCK (2)
- contraction of the gall bladder, squeezing stored bile into the cystic duct and through the common bile duct
- relaxation of the sphincter around the greater duodenal papilla allowing bile to flow into the duodenum
other vital functions of the liver (9)
- carbohydrate metabolism
- lipid metabolism
- protein metabolism
- processing drugs and hormones
- excretion of bilirubin
- synthesis of bile salts
- storage
- phagocytosis
- activation of vitamin D
where the majority of digestion and absorption occurs
Small intestine
S.I divided in three regions
duodenum
jejunum
ileum
permanent ridges in the mucosa
being in the duodenum and end in the mid-portion of the ileum
circular folds
role of circular folds in the SI
enhance absorption by increasing surface area and causing chyme to spiral through the SI
arterial supply of SI
superior mesenteric and gastroduodenal
innervation of SI
superior mesenteric plexus and vagus nerve
two autonomic plexuses are found within the wall of the SI
- myenteric plexus
2. meissner’s plexus
layers of the small intestines
- mucosa
- submucosa
- muscularis
- serosa
greatly increase the SA of the epithelium available for absorption and digestion (in the mucosa)
villi
each villi contains 5 things
lamina propria central lacteal arteriole venule blood capillary
mucosa of SI - the epithelium consists of (4)
absorptive cells
goblet cells
enteroendocrine cells
paneth cells
mucosa of SI - digest and absorb nutrients
absorptive cells
mucosa of SI - secrete mucous
goblet cells
mucosa of SI - secrete secretin, CCK or GIP
enteroendocrine cells
mucosa of SI - secrete the bacterial enzyme lysozyme and has some phagocytotic functions
paneth cells
mucosa of SI - lamina propria has many MALT (2)
solitary lymphatic nodules (distal ileum)
peyer’s patches (distal ileum)
submucosa of SI content
duodenal glands (Brunner’s)
role of Brunner’s gland (duodenal)
secrete an alkaline mucous which helps neutralize gastric acid in chyme
why is Brunner’s gland role important
because the gastric juice is acidic but the farther you go down the GI tract, the less mucous you need as it is less and less acidic
muscularis layer of SI (2)
longitudinal and circular layers
serosa layer of SI
most superficial
slightly alkaline
contains mucous and water
aids with the absorption of substances as they come in contact with the villi
clear yellow fluid (1-2L/day)
intestinal juice
absorptive epithelial cells synthesize many digestive enzymes and insert them into the microvilli
brush-border enzymes
two types of movement occur in the small intestine
segmentation
migrating motility complex (a form of peristalsis)
localized, mixing contractions that occur in portions occupied by large volumes of chyme
mixes chyme with digestive juices
brings food particles in contact with the mucosa for absorption
Segmentation
segmentation starts with the contraction of what
circular muscle
where does MMC begins
lower portion of the stomach
when does absorption occurs in the SI
once food has been changed into forms that can pass through the epithelial cells lining the mucous into blood and lymphatic vessels
about __% of the absorption occurs in the SI
90%
10% of absorption occurs in __ and ___
stomach and large intestine
terminal portion of the GI tract
large intestine
LI is divided into 4 main regions
cecum
colon
rectum
anal canal
functions of the large intestine (4)
complete absorption, produce certain vitamins, form feces, and expulse feces from the body
attached to posterior wall by the mesocolon
large intestine
LI - hangs from ileocecal sphincter
cecum
LI - twisted, coiled tube attached to the cecum
appendix
divisions of the colon
ascending, descending, transvers and sigmoid
LI - abrupt turn inferior to the liver
right colic flexure
LI - abrupt turn inferior to the spleen
left colic flexure
LI - begins near L. iliac crest and ends at the level of 3rd sacral vertebrae
sigmoid
LI - guarded by an internal sphincter of smooth muscle and an external sphincter of skeletal muscle
anus
arterial supply of LI
sup/inf mesenteric aa.
sup, middle, and inf. rectal aa.
sympathetic innervation of large intestine
celiac, superior and inferior mesenteric ganglia
parasympathetic innervation of large intestine
vagus and pelvic splanchnic nerves
t/f there are villi and circular folds in the large intestine
false
layers of large intestine
mucosa, submucosa, muscularis, serosa
muscularis layer of LI - some portions of the longitudinal muscle are thickened forming 3 bands called
taenia coli
muscularis layer of LI - tonic contractions of the bands form a series of pouches called
haustrae
passage of chyme from the ileum into the cecum is controlled by what
ileocecal sphincter
what is haustral churning
haustrae remain relaxed until they fill up
after a certain distension, the wall contracts and pushes the contents into the next haustrae
2 functions of the LI
peristalsis and mass peristalsis
t/f peristalsis occurs at a slow rate
true
mass peristalsis
strong peristaltic wave that begins in the middle of the transverse colon and rapidly drives the contents into the rectum
the final stage of digestion occurs through the activity of bacteria in the lumen
anything remaining after will not be absorbed (sent to urine for excretion)
