Circulatory system

HideShow resource information
  • Created by: esmenias
  • Created on: 01-05-16 12:26
Preview of Circulatory system

First 240 words of the document:

Esme Nias Arteries, veins and capillaries 25.1.16
Circulatory system
Carry blood away from heart
Thick, multilayered walls
Walls are capable of stretching to
accommodate the `pulse' of
Capable of expanding and
contracting to change and
maintain blood pressure
No valves
Blood inside is high in oxygen and
low in carbon dioxide except in
pulmonary artery
Blood inside is bright red
Inside, blood is under high pressure
E.g. coronary (heart), brachial (arms), carotid (head), femoral (legs), renal (kidney)
Tiny branches off the arteries
Cannot be seen with unaided eye
Thinner, less muscular walls
Feed blood into the capillaries
Narrower than arteries but wider than capillaries
Flow and pressure of blood is
controlled by sphincters
(outside of capillaries)
Microscopic vessels (8 um)
Erythrocytes pass through in
single file
Walls only one cell thick (to
facilitate diffusion)
Thinness allows for easy
diffusion outward or inwards
through single cell layer
Form capillary beds ­ network of vessels linking arterial and venous blood
Oxygen, nutrients and other materials move out of the capillaries and into the
extracellular fluid and then into cells
Carbon dioxide, wastes and other materials are picked up and move into the
capillaries (both involve diffusion)

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Esme Nias Arteries, veins and capillaries 25.1.…read more

Page 3

Preview of page 3

Here's a taster:

Esme Nias Arteries, veins and capillaries 25.1.16
Heart pumps towards head via peristalsis
Closed systems:
Blood stays entirely in vessels
Tissue fluid leaves vessels to bathe tissues and cells
Blood can be pumped at higher pressure so higher flow
= waste can be removed quicker and the supply is quicker
E.g.…read more


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »