Blood volume

What are the 2 major fluid compartments in the body?

Extracellular and intercellular

Most of the fluid in our body is?

Intercellular (28L)

How much L is extracellular?

14L

What 2 things is extracellular fluid made up of?

Plasma (3L) and interstital (11L)

What is the total volume of fluid in our body?

42L

How is the volume in the intracellular compartment maintained?

Via osmosis

How is the volume in the interstitum compartment maintained?

Via a colloid osmotic pressure (adsorption) and hydrostatic pressure (filteration) THEY ONLY WORK IN THE CAPILLARIES as all the other blood vessels r too thick for these processes to occur

Failure to regulate fluid compartments leads to what?

Oedema; fluid build up in certain parts of the body e.g burn or friction blister

What is osmosis?

The total number of particles in a solution is measured in terms of?

Osmoles

Osmoles is independent to?

Molecular weight

Cellular membrane

What is osmotic pressure?

If the extracellular fluid volume is the same as intracellular it is referred to as?

Isotonic (no change)

If the extracellular fluid volume is less then the intracellular it is referred to as?

Hypotonic (cell swells) ; liquid moves in

If the extracellular fluid is more than the intracellular it is referred to as?

Hypertonic (cell shrinks) ; fluid moves out

What is the colloid osmotic pressure?

Capillary membrane is semi-permeable

• Permits diffusion of ions, water, oxygen, nutrients and waste

• Not proteins

only difference is plasma contains 6x the conc of protein

Colloid osmotic pressure

• Pressure exerted by the higher levels of protein in the plasma compared with the interstital fluid

• Draws water back into plasma by osmosis (adsorption)

• 28mmHg (plasma) - 3mmHg (interstitium) = 25mmHg

Hydrostatic Pressure

• It is the force exterted by the blood upon the capillary walls i.e blood pressure

• It drives blood from plasma into interstitial space

  • Pressure drops as the blood moves through the capillaries (35mmHg to 15mmHg)

What system in our body removes liquid/fluid from capillaries?

The lymphatic system

Name given to the removal of fluid from the plasma

Bulk flow

Lymphatic system

Lymph system is parallel vascular system with two major functions: draining fluid from the tissues and returning to the cardiovascular system and maintenance of the immune response

How much fluid (plasma) passes a day?

8L

Where does fluid (plasma) pass from?

The blood into the interstitial area (surrounds cells in the tissues)

Excess fluid then passes into what?

Lymph capillaries

After passing through the lymph capillaries is then passes through the?

Lymph nodes (detection of infection) before passing back to blood stream at the neck (largest is thoracic duct that drains into subclavian vein)

What do lymph vessels contain?

Valves

What do the valves then cause?

Fluid being forced along by action of muscles and breathing (respiration).

Larger lymph vessels are surrounded by what?

Smooth muscle which contract spontaneously and are driven by pacemaker cells (~ heart)

What does the lymphatic system also collect?

Fats from the intestines/liver and deposits into veins

Lymph fluid contains what cells?

White immune blood cells (lymphocytes, macrophages, dendritic cells)

What would the lympatic system collect?

Antigens (proteins produced by pathogens)

Antigens recognise what lympohcyte?

B-lymphocytes in lymph nodes leading to activation of immunity

B-cells proliferate to produce?

Antibodies as lymph nodes also contain multiple other immune cells (swelling can occur)

What happens during heart failure?

Fluid leaves capillaries

Decrease in colloid osmotic pressure

Again more liquid being pushed out; liquid isnt sucked back into the blood

Blockage of lymph nodes

Intracellular oedema

Loss of ion within intra and extracellular environment

Summary