Circulatory system

Function of the circulatory system

Primary function: transport of nutrients to/from somatic cells

Other functions: clotting, waste removal

Circulatory system components

3 components: 1. Blood vessels2. The heart3. Blood

Blood Plasma

◦ water◦ proteins (eg. insulin)◦ micronutrients

Blood cells◦ red (erythrocytes)◦ platelets (thrombocytes)◦ white (leukocytes)

Blood

Red blood cells carry oxygen to cells and carbon dioxide waste for elimination.

White blood cells help fight infection.

Platelets help stop blood flowing by forming clots.

◦ Nutrients and waste enter/leave cells via passive (eg. diffusion) and active transport

What colour is your blood?

OXYGENATED DEOXYGENATED

vs

Pulmonarycircuit

Systemiccircuit

Anatomy of blood vessels

Arteries, arterioles◦ vessels that carry nutrients away from the heart

Capillaries◦ smallest blood vessels that are one cell layer thick

Veins, venules◦ vessels that carry nutrients to the heart

Anatomy of blood vessels

FYI: Blood vessels are lined with muscle and can constrict or dilate to modify blood pressure

Nutrient exchange

(to lungs)(to lungs)

(from lungs)(from lungs)

(from body)

(to body)

(from body)

Heartbeat◦ The “thump-thump” of your heart is the valves

closing

◦ Cardiac muscle tissue in the heart contracts on its own without nervous stimulation – this is called being myogenic

◦ A region in the right atrial wall acts as a pacemaker and initiates each contraction by sending its own impulse

◦ This impulse is distributed across the heart and sequentially triggers the proper chamber contractions

Heartbeat

Blood pressure measurements

Blood pressure is a measure of the force of blood pressing against the arterial/venule wall

It is a measure of 2 pressures:◦ Systolic pressure (when ventricles contract – highest pressure)◦ Diastolic pressure (when ventricles relax – lowest pressure)

This is called a

sphygmomanometerThis is called a stethoscope

Try this… Pg. 334, #1 – 3, 5 – 6 & 8