Circulatory system

Function of the circulatory system Primary function: transport of nutrients to/from somatic cells Other functions: clotting, waste removal

Circulatory system components Blood vessels The heart Blood

Blood Plasma Blood cells water proteins (eg. insulin) micronutrients red (erythrocytes) platelets (thrombocytes) white (leukocytes)

Blood White blood cells help fight infection. Red blood cells carry oxygen to cells and carbon dioxide waste for elimination. 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

Pulmonary circuit             Systemic circuit

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 body) (from body) (to lungs) (to lungs) (from lungs) (from lungs) (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 sphygmomanometer This is called a stethoscope

Try this… Pg. 334, #1 – 3, 5 – 6 & 8