Digestive Dystem 2 Flashcards
what is the breadth and length of the small intestine
-3cm width
-6m long
nam the 3 major segments of the small intestine and and their measurments
-duodenum (25cm)
-jejunum (2.5m)
-ileum (3.5m)
list the functions of small intestine
-major site for digestion of food
-absorption of nutrients and vitamins
-removal of water from ingested fluids
why does the mucosa of SI produce secretions
-primarily water, electrolytes and mucus
-lubrication
-protect SI walls from acidic chyme and digestiv enzymes
describe the duodenum
curves to the left
-head of pancreas sits in curve
2/3 way down descending part are 2 small mounds
-major and minor duodenal papillae
-opening to ducts from liver and pancreas
folds and projections in mucousa/sunmucousa
-increase surface area 600 fold for better digestion/absorption
describe the jejunum and ileum
-similar structure to duodenum
-decreased diameter, thickness of intestinal wall and number of folds & projections farther away from stomach
-jejunum major site of nutrient absoprtion…illium less so
describe the lymph nodes in ileum mucosa/submucoa
=peyers patches
-defend against microorganism ingested
describe lleocecal junction
where SI meet LI
-sphincter and valve preset to ensure 1 way flow
list the functions of the liver
produce and secrete bile
-600-1000ml/day
-neutralise and dilutes stomach and emulsifies fats
storage
-glycogen, fat, vitamins, copper and iron from blood
removes
worn out blood cells and other debris
inter-converts nutrients
- ingested nutrients not always in form need; liver can convert excess proteins and lipids from blood from GI into what it needs
detoxifies
-drugs/poisin/toxins
list the properties of the liver
-largest internal organ
-weighs 1.4kg
-in upper right abdomen, directly under diaphragm
-covered in visceral petronium
list the 4 lobes of the liver
major-right and left
minor-caudate and quadrate
-seen from inferor
-right and left seperated by falciform ligament
-fold of petronium
discuss the hepatic porta (area on inf surface)
-hepatic portal vein, hepatic artery and hepatic nerve plexus enter liver
-lymphatic vessel exit liver
-two hepatic ducts exit
discuss hepartic ducts
-drain bile from liver
-R and L unite=common hepatic
-joins cystic duct from gallbladder=common bile duct
discuss the hepatic portal circulation
hepatic artery- 02 blood from aorta (supplies hepatocytes with 02)
hepatic vein- returns deoxygentated blood into vena cava
hepatic portal vein- carries nutrients rich in deoxygenated blood from intestine to liver
-supplies hepatocytes
-substances absorbed in SI processed in liver before continuing to heart and rest of body
what happens to drugs absorbed through GI tract
they are metabolized by liver before reaching general circulation
-the first pass effect
-certain drugs can only be taken via certain routes to avoid or go through liver
list the possible liver diseases and describe them
liver renowal
-most mature hepatocytes can proliferate and replace lost part of liver
-if severly damaged hepatocytes dont have enough power to replace lost parts
-liver transplant required
hepatitis
-inflammation of liver caused by alcohol consumption or viral
-if untreated hepatocytes die and replaced by scar tissue-liver function loss
cirrhosis
-death of hepatocytes and replaced by fibrous tissue
-liver becomes paler and colour firmer
-build up of fibrous tissue impeded blood flow through liver
-loss of hepatocytes reduces liver function
-result in jaundice (yellow skin) due to build up of bile
-caused by alocoholism, hepatitis or nutrient deficiencies
describe the gall bladder
pear shaped muscular sack on post inferior surface of liver
-8x4cm
-stores 50-70ml bile from liver
-also concentrates bile by absorbing water from it
after meals, gallbladder contracts and bile exits into duodenum
describe gallstones
bile pigments and/or cholesterol from liver precipitates in GB if their concerntrations are too high
-can have no symptoms if stone less than 1cm
-if larger, can block cystic duct causing pain , nausea and jaundice
-can be due to excess cholesterol in diet
list th ebillary ducts
cystic duct/common hepatic duct/bile duct/descending part of duodenum
describe the pancreas
-large glands (endocrine/exocrine)
-retroperitonial
head-located in C shaped curve of duodenum
tail-tapers towards spleen
list the functions of the pancreas (glands)
endocrine- pancreatic islets produce insulin to regulate blood glucose levels
exocrine-groups acini from lobules and secretes digestiv enzymes (pancreatic juice) into the duodenum through pancreatic duct
-pancreatic duct joins common bile duct and enters duodenum
what 2 ducts can gallstones block
bile ducts
pancreatic duct
discuss how the liver, gallbladder, pancreas and bile ducts work
1.the hepatic duct, whic carries bile from liver lobes, combine to form common hepatic ducts
2.the common hepatic duct combines with cystic duct frim gallbladder to form commmon bile duct
3.the common bile duct and pancretic duct combine to form hepatopancreatic ampulia
4.the hepatopancreatic ampulla empties bile and pancreatic secretions into duodenum and major duodenal paila
5.the accessory pancreatic ducts empties pancreatic secretions into duodenum at minor duodenal papilla
describe the large intestines
wider but shorted
-1.5m (than SI)
six major segments
-cecum
-ascending, transverse, descending and sigmoid colon
-rectum
converts chyme—feces in colon
-absorb water/salts and secretion of mucus
-action of microorganism
discuss the movement throughout large intestine
movement is sluggish throughout
-18-24hrs
-1500ml/day chyme enters cecum
-90% reabsorbed
-produces 80-150ml o ffeces
discuss the cecum of large intestine
-proximal blind sac where meets SI
-ileocecal junction
-extends-6cm inferiorly
veriform appendix attatched to cecum
-small blind tube
-contain numerous lymph nodules
-immune function
discuss the colon of large intestine
-ascending, transverse, descending, sigmoid
-1.5-1.8m long
-mucosa no folds/villki (unlike SI)
-instead has numerous straight tubular glands=crypts
discuss rectum or large intestine
-straight muscular tube
-connects sigmoid colon to anus
-thick muscular tunic, compared to rest of digestive tract
discuss anal canal of large intestine
-last 2-3cm digestive tract
-ends at anus
-very thick muscular tunic
-forms internal anal sphincter (smooth muscle)
-skeletal muscl external anal sphincter inf
describe hemorrhoids
rectal vein enlargement or inflammation
-pain, bleeding or ithcing
-treated by changing diet or medication
state which components of the liver are in the
i)intraperitonial segments
ii)retroperitonial segments
i) cerum/appendix
transverse colon
sigmoid
ii)ascending colon
descending colon
rectum
discuss appendicitis including symptoms and treatment
Inflammation of vermiform appendix
-Usually due to obstruction in appendix
-Secretions cant pass so accumulate
-Appendix swells
Symptoms:
Pain
Loss appetite
Fever
Nausea
Vomiting
Diarrhoea or constipation
Treatment – appendectomy
-If appendix bursts, infect spreads throughout peritoneal cavity
-Peritonitis
what is the difference in rectal positioning in males and females
male-straighter
females-more forward and curved and lies higher
stat ethe diseases that can evolve in the digestive system and describe them.
Peptic ulcer – lesions in lining of stomach or SI, usually due to bacterial infection
IBS – unknown causes, results in constipation alternating with diarrhoea
-High familial incidence
Constipation – slow movement faeces through LI so increased fluid absorption & faeces become hard & dry
-Can be cause by irritation in sigmoid colon
-Prevented by high fibre diet
