Week 7 - Liver Anatomy & Portal Circulation Flashcards
where is the liver located
- in the RUQ below the diaphragm
what is the portal triad?
area of the liver containing:
- portal arteriole
- portal venule
- bile duct
what is the portal arteriole
- artery that carries O2 rich blood to the liver from the heart
what is the portal venule
aka the portal vein
- vein that carries nutrient rich blood from the GI tract, spleen, and pancreas
what is the bile duct
- drains bile from the liver into the gallbladder
- carries bile away from cells
what is the functional unit of the liver
- hepatic lobule
what are sinusoids
- fenestrated blood vessels that carry blood from the hepatic arteriole & portal vein into the central vein
what is the central vein
- the large vein found in the center of the hepatic lobeules
- it carries blood into the hepatic veins which then drains into the IVC
what are hepatocytes
- liver cells
what is the function of the fenestrations in the sinusoids
- allows O2 and nuterients to squeeze thru them and enter the hepatocytes
list the functions of the liver (9)
- produce bile salts
- excrete bilirubin in the the bile
- destroy bacteria in the portal blood
- maintain BG
- produce urea
- regulate lipid profile
- metabolize & detoxify drugs, hormones, and toxins
- produce proteins
- produce IGF
how does the liver help regulate BG
either:
- converst glucose into glycogen if BG is high
- or breaks down glycogen into glucose if its low
what types of proteins (or protein-like substances) does the liver produce (4)? what happens to these proteins after?
- coagulation factors/clotting proteins
- albumin
- angiotensinogen (glycoprotein)
- IGF –> insulin-like growth factors
- then released into the blood
how does the liver effect our lipid profile
produce
- FA
- triglycerides
- cholestrol
- lipoproteins (LDL, VLDL)
how does the liver produce urea
- detoxifies ammonium to create urea
how does the liver create bile salts?
- converts cholestrol into bile salts
how does the liver destroy bacteria in the portal blood
- thru kupffer cells
what are kupffer cells
- modified macrophages found in the sinusoids
what is the function of kupffer cells
- destroy old red & white blood cells, bacteria, and foreign substances that enter the sinusoids
what is bile
bile salts + water + bilirubin
what is bilirubin
- biproduct of the breakdown of Hgb
what is angiotensinogen
- a glycoprotein which renin acts on to convert it into angiotensin
- plays role in the stimulation of the adrenal gland & simulating vasoconstriction
what is the function of aldo
- tells us to keep water & Na, and get rid of K+
what is IGF
a peptide hormone that plays a role in stimulating growth
what are the superior & inferior mesenteric veins
- veins that drain the blood from the GI tract that contains the absorbed nutrients
- come together to drain to the Hepatic portal vein into the liver
when is bilirubin formed
- during the breakdown of Hgb
where does Hgb get broken down?
- within macrophages in the spleen & liver sinusoids
what does the globin portion of Hgb get broken into ?
- amino acids
what does the heme portion of Hgb get broken into
- iron
- bilirubin
how is bilirubin transported
- does not dissolve well in the blood
= must be transported bound to albumin
is bilirubin initially water soluble? what does this mean
- no
= cannot be excreted in the urine or bile
how does bilirubin become water soluble? what is this called?
conjugation:
- it is conjugated to glucuronic acid
where does conjugation take place?
- in the smooth ER of the hepatocytes
why does bilirubin need to be conjugated?
- so it can be excreted in the bile
what is another word for conjugated bilirubin? what about unconjugated bilirubin?
- conjugated = direct
- unconjugated = indirect or free
