Blood Vessels and The Heart The Circulatory System

Blood Vessels and The Heart

The Circulatory System • The circulatory system is made up of the heart and a system of blood vessels. • 3 kinds of blood vessels are: 1. arteries 2. veins 3. capillaries

Arteries • carry blood away from the heart • carry blood toward the organs and tissues of the body • have thick, elastic walls • smallest arteries are called arterioles

Veins • carry blood toward the heart • carry blood away from the organs and tissues of the body • have thin walls, they are not as elastic • contain valves to prevent backflow of blood • Smallest veins are called venules

Varicose Veins

Capillaries • connect arterioles to venules • they have thin walls that allow the exchange of nutrients, waste, and oxygen between the blood and the body cells

Capillaries

artery arteriole capillary venule vein

The Heart • Acts as a double pump • Made up of cardiac muscle • Has 4 chambers: 2 atria – upper, thin walled chambers 2 ventricles – lower, thick walled chambers • What is the pericardium? – A tough membrane that covers and protects the heart

The Heart

The Heartbeat • The heartbeat has 2 periods Systole – period of contraction Diastole – period of relaxation

Blood Pressure • What instrument is used to measure blood pressure? – Sphygmomanometer • What is normal healthy blood pressure in a resting adult? – 120/80 • What is hypertension? – High blood pressure

Sphygmomanometer

• What is the function of the pulmonary artery? – Takes blood to the lungs • Why is the aorta important? What does it do? – The aorta is the largest artery in the body – It takes blood to all other body tissues • What is the sinoatrial node? What does it do? – It is the pacemaker. It sends an electrical impulse which triggers contraction of the heart

Sinoatrial Node

The Artificial Pacemaker • Implantable pacemakers constructed by engineer Wilson Greatbatch entered use in humans in 1960. Greatbatch advanced the development of the implantable pacemaker. He used mercury batteries. The first patient lived 18 months longer. • This development was overtaken by the development in 1970 of the lithium-iodide cell battery by Wilson Greatbatch. Lithium -iodide or lithium anode cells became the standard for future pacemaker designs.

The Artificial Pacemaker