Circulatory system

Blood=

-essential to body functions

-Pumped by heart round network veins, arteries and capillaries

-Delivering oxygen, food, other essential substances to tissues

-Extracts carbon dioxide + other waste products= might poison the system

Red blood cells=

-transporters- taking oxygen from lungs to tissues

-Pick up carbon dioxide = waste product of cell function

-Take it bake to lungs where breathed out

-able to do this as = contain haemoglobin

-Haemoglobin is a substance combines easily with oxygen= blood bright red colour

-made in bone marrow

-only last about 120 days= b4 destroyed by cells made in spleen

White blood cells=

- bigger + different for RBC

-3 main types

 -Move with creeping motion

-Fight against diseases

 -Made in bone marrow but some in spleen and lymph glands

 -Don’t live long= especially when fighting diseases

Plasma =

mainly water

-Diffuse through thin walls of small blood vessels= capillaries

-Directly connected to  fluid= bathes surface body cells

Platelets =

-tiniest cells

- tiny drop= 250 million

-make blood clot when bleeding

- Cut or graze= stick to wall of skin form plug an stop bleeding

- Other substances interact to form fibrin= effect more permanent repair

Heart

Large muscular organ= slightly more to left

Pump blood around the body= force of each beat transmitted along arterial walls  

Heart= between, the sternum in front and spine behind

Below heart= diaphragm  and at each side= lungs

Arteries

- carry oxygenated blood around the body

- thicker than veins- withstand pumping force and keep in oxygenated blood

-main arterie= the aorta- branches and gets smaller(really small=arterioles) so can pump to different parts of bodies