Download Liver Functions

Human Digestion and
Nutrition
LIVER – ORGAN OF MANY FUNCTIONS
Liver Overview
• Football-sized in upper right abdomen
• Largest organ by weight (~3 lbs.)
• “Swiss Army Knife”
• Performs functions related to:
oDigestion
oExcretion
oMetabolism
Carbohydrates
Fats
Proteins
Liver and Blood
Blood enters liver from two sources
◦ From intestines through portal vein
◦ Includes all absorbed nutrients
◦ Some are processed/altered
◦ Some are released directly
◦ From heart through hepatic artery
◦ Includes oxygen/nutrients for liver cells to
perform their functions
Liver Functions – Digestion
Liver makes/
secretes bile
• To gall
bladder
Gall bladder
makes/secretes
bile salts
• To small
intestine
Bile salts break
up large fat
globules
• Mechanical
Digestion
Lipase breaks up
small fat globules
• Chemical
Digestion
Glycerol and fatty
acids
• Absorbed to
blood
Liver Functions – Carbohydrate Metabolism
High glucose – Glucose converted to
glycogen
Low glucose - Glycogen converted to
glucose
High glycogen – glucose stored as fat
Low glycogen – fat and protein
converted to glucose
Regulated by hormones
Used primarily for cell respiration/energy production in all cells
Liver Function – Lipid/Fat Metabolism
oFatty acids converted to molecules
used in cell respiration
oGlycerol converted to molecules
used in cell respiration
oFatty acid and glycerol are put
together to make fat molecules for
energy storage
oFatty acid and glycerol are put
together to make fat molecules used
in cell membranes
Used primarily for cell respiration and cell membranes in all cells
Liver Function – Protein Metabolism
Amino acids go directly to cells for protein
synthesis
Amino acids used by liver to make proteins for
blood
Amino acids converted to different amino acids
as needed by cells
Amino acids converted to molecules for energy
Amino acids broken down for nitrogen to build
DNA/RNA
Used primarily for protein synthesis in all cells
Liver Function - Excretion
Removes nitrogen compounds from
amino acids and converts to urea
Removes and breaks down
old/damaged red blood cells from
blood
Removes toxins from blood –
including alcohol and drugs (legal
and illegal)
All of these products are filtered
from blood by the kidneys and
excreted in urine
Liver Functions
Liver Functions Video
Liver Ted Talk