The Liver Flashcards
What is the liver responsible for?
-creating lipids that circulate through the body
- converting excess carbohydrates and proteins into lipids(fats) for energy storage
What does the hepatic vein carry?
deoxygenated, filtered blood
Where does the hepatic vein flow?
To the heart
What does the hepatic artery carry?
Oxygen-rich blood. It branches extensively to provide the liver with oxygen
From where does the hepatic artery flow from?
From the heart to the liver
When you look at a diagram of the liver, what is left and what is right?
The left lobe is seen on the right side and is seen as smaller and vise versa.
What is the liver connected to?
The pancreas, gall bladder and small intestine.
What are the different parts of the Gall bladder?
Hepatic duct, cystic duct, common bile duct.
Why is the portal vein so nutrient-rich?
It comes from the small intestine, brings the absorbed nutrients, but also carries toxins. The liver cleanses it before moving onto the heart and body.
What does the gall bladder look like before and after a meal?
Before the meal, it is as big as a small pear, after is as small as a deflated grape/
What are sinusoids?
Specialized blood vessels in the liver?
What is one of the structural features of a sinusoid?
It has fenestrations.
What is a hepatocyte?
A cell in the liver
Compare sinusoids to capillaries.
Capillaries have a narrower lumen
Capillaries can be fenestrated
Sinusoids are fenestrated
sinusoids have wieder lumen
sinusoids have phagocytes (white blood cells)
Explain the structure of a sinusoid
When cut through, it looks like a hexagon. In the center there is the “central vein”. At each point of the hexagon, the hepatic artery and portal vein bleed into the central vein. Along the channel, the bile duct runs. The channel of the sinusoid (including blood from the portal vein and hepatic artery) in embedded with phagocytic cells which snatch red blood cells once they are old.
How is glucose stored in the liver?
It is stored as glycogen when glucose levels are high.
When glucose levels are low, glycogen is broken down into glucose and released into the blood stream.
How does glucose get into the liver?
It is absorbed by epithelial cells via active transport
It enters the capillary via facilitated diffusion
Now in bloodstream
What is the mg/mL of glucose that is considered homeostasis
90 mg/ 100mL
Explain how the liver reacts to an increase in glucose in the bloodstream after eating.
Due to food intake, glucose levels rise. This stimulates the beta cells of the pancreas, the pancreas releases insulin. A condensation reaction occurs and glucose is turned into glycogen and is stored in the liver and muscles. The glucose level drops and homeostasis is achieved.
Explain how the liver reacts to a drop in Glucose after not eating.
Glucose levels drop in the bloodstream which stimulates the alpha cells in the liver, the pancreas releases glucagon (hormone) which triggers the hydrolysis reaction of glycogen to be broken down into glucose. Glucose is released into the bloodstream, levels rise and the body achieves homeostasis again.
What hormone is released when the alpha cells of the pancreas are stimulated?
The hormone glucagon
What hormone is released when the beta cells of the pancreas are stimulated?
Insulin
What is iron needed for?
It is needed for oxygen transportation.
What is iron a component of?
hemoglobin, it is bound to the heme group
What captures iron?
Phagocytes
Why is iron stored in haemoglobin?
Because when it is free-floating, it is toxic to cells. So when iron is needed, it will be transported within ferritin proteins.
How many iron ions can be stored in one ferritin protein?
Up to 4500
Where is iron stored when in excess?
In the liver
Where is vitamin A found?
in eye rod cells
What is vitamin A ?
A pigment found in eye rod cells
Where is vitamin A stored?
In lipids within the liver, this is where 80% of the total vitamin A is stored.
What is another term for red blood cells?
Erythrocytes
What is another term for Vitamin D?
Calciferol
Explain the production of Vitamin D within the body
An active precursor of vitamin D is synthesized in the skin from cholesterol through sun. The liver then converts this precursor into active Vitamin D.
What is vitamin D neded for?
Cells need it to absorb calcium
What does the liver convert proteins and amino acids into?
Carbohydrates and lipids