The Cardiovascular System Chapter 13

By the end of today, you should be able to:•Describe the 3 major elements of the cardiovascular system.•Contrast the 2 “circuits” or “routes” that blood takes throughout the cardiovascular system.•Relate the effects of activity/exercise to the cardiovascular system

The Closed Circulatory System•Humans have a closed circulatory system (blood confined to vessels).

•The heart pumps blood into large vessels that branch into smaller ones leading into the organs. (arteriesarteriolescapillaries)

•Materials are exchanged by diffusion b/w blood and the fluid bathing the cells (interstitial fluid)

The Cardiovascular System

•Three Major Elements – Heart, Blood Vessels, & Blood•1. The Heart• cardiac muscle tissue• highly interconnected cells

–4 chambers•Right atrium•Right ventricle•Left atrium•Left ventricle

Circuits•Pulmonary circuit–Sends oxygen-depleted (deoxygenated) blood to lungs to pick up oxygen & unload CO2

•Systemic circuit–Sends oxygen-rich (oxygenated) blood & nutrients to all body cells and remove wastes

The Cardiovascular System

• 2. Blood Vessels -A network of tubes

– All blood vessels in body, joined end to end, would stretch 62,000 miles (2.5 times around the Earth)

• Arteriesarterioles • Move blood away from the heart• Elastic Fibers• 3 layers (endothelial tissue,

smooth muscle, connective tissue)• Carries blood under relatively high

pressure from heart to arterioles• Largest artery = aorta (diameter

of garden hose)

Blood Vessels

•Capillaries • where gas exchange takes

place• Materials diffuse thru slits

(openings) in capillary walls• Single layer of epithelial

tissue• Connect arterioles to

venules• Serve the Respiratory

System FYI--(There is always 1/5 of our blood supply in the lungs)

Blood V essels

•VeinsVenules • Move blood towards the

heart• 3 layers (similar to

arteries except middle layer poorly developed)

• Carries blood under low pressure

• Many have valves that prevent backflow of blood

• Largest vein = inferior vena cava

• heart anatomy video model

The Cardiovascular System

3. The Blood• RBCs (erythrocytes)• WBCs (leukocytes)• Platelets

(thrombocytes)• Plasma

Exercise

• CV System adapts to exercise• Increase in heart pumping efficiency,

blood volume, blood hemoglobin concentration, # of mitochondria in muscle fibers

• All of these improve oxygen delivery to and utilization by muscle tissue

• Good=Slow, steady buildup of exercise frequency & intensity

• Bad=suddenly shoveling snow, running 3 miles when body isn’t used to it

Inside the Human body video – 48 min

Anatomy of the human body 1Plastination, Heidelberg, Germany