Human Physiology Liver Flashcards

1
Q

Where does most of the blood coming to the liver come from

A

Hepatic Portal Vein

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2
Q

Liver is a double blood supplied organ, what is the supply

A

Hepatic Portal Vein (From the stomach and the intestines)
Hepatic Artery ( From the aorta )

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3
Q

Modified Capillaries in the liver

A

Sinusoids
- Wider
- More Gaps
- No Basement Membrane

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4
Q

Liver Cells name

A

Hepatocytes

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5
Q

Walls of the sinosids are lined with ??

A

Kupfer Cells
- Fixed phagocytotic cells in the siosuids and engulf and break down damaged and old red blood cells.

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6
Q

Functions of the Liver

A

1) Removes Toxins
2) Synthesis of plasma proteins
3) Synthesis of cholesterol
4) Surplus of cholesterol is converted to bile salts (Synthesis of bile salts)
5) Regulation of nutrients
6) Storage of nutrients
7) Breakdown of Red Blood Cells

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7
Q

Example of negative feedback that takes place in the liver

A

Synthesis of cholesterol

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8
Q

How is iron stored in the liver

A

In specific protein called Ferrin

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9
Q

Erythrocytes Life Span

A

120 Days

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10
Q

Describe the Breakdown of Erythrocytes

A

Starts with phagocytosis of RBC, by Kupffer cells.
At the end of their life span, proteins in the plasma membrane become modified to make them recognizable.
These modified cells are taken up by the Kupffer cells in the sinusoids by phagocytosis and are broken down to their components.

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11
Q

What causes the feces to be colored

A

Bilirubin, that is released by the blood.
Bilirubin is released in the blood, taken up by hepatocytes and converted to bile pigment and enters the bile which i released into the duodenum. Gut bacteria convert this into another yellow pigment that colors the faces.

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12
Q

Describe Jaundice

A

Condition where the skin and whites of the eyes become yellow
Happens when the pigment bilirubin accumulates in the blood which is then deposited in tissues.

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13
Q

Causes of Juandice

A

1) Pre hepatic Jaundice
2) Intra hepatic Jaundice
3) Post hepatic Jaundice

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14
Q

Consequences of Jaundice

A

Adults
- Itchy skin

Children
- Particular parts of the brain can become damaged resulting in deafness and cerebral palsey

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15
Q

Why do newborns frequently develop jaundice

A

Breakdown of red blood cells happen much faster than in children and adults.

There may not be enough liver enzymes that process biliriburin

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16
Q

Hepatic Circulation occurs through

A

Simple Diffusion

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17
Q

Whats the core of the liver functions

A

Liver functions to process nutrients absorbed from gut, hence regulating the body’s metabolic processes

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18
Q

What is liver composed of

A

Liver Lobules

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19
Q

Reasons to why sinusoids are used

A

Increased permeability thus allowing larger molecules such as proteins to enter and leave the bloodstream.
This is made possible due to its incomplete discontinuous basement membrane
and large intracellular gaps

20
Q

Examples of nutrients stored within the Liver

A

A, D, glycogen, iron

21
Q

Small intestine to Liver connected by

A

Hepatic Portal Vein

22
Q

Carbohydrate Metabolism in the liver

A

Excess glucose in bloodstream stores as glycogen
When blood glucose levels fall, the liver breaks down glycogen into glucose to export it to body tissues.
When hepatic glycogen reserves become exhausted, liver synthesizes glucose from other sources such as fats.

DONE VIA HORMONAL CONTROL - glucagon and insulin

23
Q

Protein Metabolism in the liver

A

Body can not store AA, so they must be broken down when in excess.
Amino Acid breakdown releases toxic component - Amine group
Liver is responsible for the removal of the amine group (deamination) and its conversion into a harmless product.
Amine group converted to urea by liver, that is excreted within urine.
Liver can synthesize non essential AA from surplus stock (transamination)

24
Q

Fat Metabolism

A

Liver is a major site for converting excess fats, and proteins into fatty acids and triglycerides.
LDL and HDL cholesterol

25
Q

Detoxification

A

Liver removes toxins from the blood, detoxifying them
Liver acts on drugs, and toxins that have entered the bloodstream.
1) Many of these toxic compounds are fat soluble making them difficult for the body to excrete
2) These compounds are converted into less harmful and more soluble forms to be excreted from the body

26
Q

Conversion of Toxins

A

Converted to less harmful chemicals by oxidation, reduction and hydrolysis. These converted chemicals are then attached to another substrate, via conjugation. Rendering the compound less harmful and functions to make it water soluble. The water soluble compounds can now be excreted from the body within urine by the kidneys.

Via : cytochrome p450 enzyme groups

Produce : Damaging free radicals that are neutralized by antioxidants within the liver.

27
Q

Function of cholesterol

A

Membrane Fluidity

28
Q

Plasma Proteins produced in

A

The rough endoplasmic reticulum in hepatocytes, and transported into blood via Golgi apparatus.

29
Q

Types of plasma proteins

A

Albumins
Globulins
Fibrinogen
Others

30
Q

Percentage of Albumins

A

60

31
Q

Percentage of globulins

A

30

32
Q

Percentage of Fibronigen

A

4

33
Q

Percentage of others

A

<1

34
Q

Functions of Albumins

A

Regulate the osmotic pressure of the blood/ body fluids

35
Q

Function of globulins

A

Immune system, and transport proteins

36
Q

Function of fibrinogen

A

Involved in clotting process

37
Q

Others function

A

Various functions

38
Q

Kupffer Cells

A

Specialized Phagocytes within the liver that engulf RBC and break them down

39
Q

What do kuppfer cells break down heamolobin into

A

Globin and iron containing heme groups

40
Q

What happens to globin

A

Digested by peptidases to produce AA (Recycled or metabolised by the liver)

41
Q

What happens to Heme

A

Broken down into iron and bilirubin

42
Q

What happens to iron

A

Must be complexed within a protein in order to avoid oxidation to a ferric state.
1) Iron can be stored by liver within protein or ferritin
2) Iron can be transported to the bone marrow within protein transferrin

43
Q

Jaundice

A

Caused by excess bilirubin (bile pigment) within th ebody

44
Q

What causes jaundice

A

Excess of bilirubin the the surrounding tissue fluid due to the impartations on the natural breakdown of rbc.

45
Q

3 causes of Jaundice

A

Liver disease
Obstruction of gall bladder
Damage to RBC

46
Q

Q: What is the swelling of the damaged tissues in the liver as a result of exposure to alcohol?

A

A: Alcohol hepatitis.

47
Q

After Kupffer cells in the liver hydrolyze the globin proteins of haemoglobin into amino acids and remove iron from each haem group, the iron is sent to the liver and to what structure to produce new erythrocytes?

A

Bone Marrow