Plasma and its Function

As you can see from this image, Plasma is the yellow liquid part of blood.

Plasma is responsible for transporting the red blood cells (Erythrocytes), white blood cells (Leukocytes) and platelets (Thrombocytes) around the body.

55% of our bloods volume is made up of plasma.

What does Plasma contain?

We already know plasma carries blood cells.
Plasma also contains the following substances;

SUBSTANCE / / ORIGIN / / DESTINATION

Carbon Dioxide (C02) / / Body / / Lungs

Digested Food / / Gut / / Liver/Body

Wastes (e.g. Urea) / / Liver / / Kidneys

Hormones / / Endocrine Glands / / Where needed

PROTEINS

Proteins approximately make up 6-8% of blood and are divided between serum albumin and varied serum globulins.

Serum albumin

made in the liver

binds small molecules for transportation

helps maintain osmotic pressure of blood

Serum globulins

Alpha globulins - Transport thyroxin and retinol

Beta globulins - Iron-transporting protein transferring

Gamma globulins - Antibodies are mostly gamma globulins and become more abundant following infections or immunisations

WHITE BLOOD CELLS

If your body needs defending -
who does it call -
the white blood cell (wbc)

When germ or infection is detected by the wbc, they race to where it is and immediately start attacking it. They have a variety of ways they can attack a germ or infection, they either produce protective antibodies to overpower or surround and devour the bacteria.

Though the wbc are an essential part of our body's defense system, they do only have a short life span. They can live anything from a few day to weeks.

7000 - 25000 wbc can be found in a single drop of blood at any one time.

This number increases if there is a particularly aggressive infection.

PLATELETS

Their sticky and their oh so funny shaped....

...but what do they do?

They are able to sense air from an open wound and are essential in the clotting factor of blood.
As soon as air is sensed they break apart and gather at the wound along with the mineral calcium, vitamin K and the protein fibrinogen to help form a clot.
The reaction of the platelet with fibrinogen forms fibrin, which resembles tiny threads.
The fibrin threads form a mesh that catch the red blood cells, and as it dries it forms a clot or 'scab'.

RED BLOOD CELLS

You will have to read the blog - 'Red blood cells - They have structure and function' for more information...

Bibliography

CG Patnership handout, wk24, Blood

http://www.fi.edu/learn/heart/blood/platelet.html