1. Chapter 33: Circulatory and Respiratory Systems

2. Chapter 33.1: The Circulatory System

3. Functions of the Circulatory System
Transports oxygen, nutrients, and body heat throughout the body
Removes wastes from tissues
Works with the immune system to protect against illness

4. Structures of the Circulatory System
Heart
Muscular pump that moves blood through the system
Has special muscle tissue called myocardium
- Divided into 4 chambers
Upper chambers are the atria (single = atrium)
Lower chambers are the ventricles
Contains valves that separate the chambers from each other

6. Structures of the Circulatory System
Blood Vessels
Include arteries
Carry blood away from the heart
Have thick, elastic walls to help them withstand blood pressure from the heart’s pumping
Include capillaries
Are small vessels that allow diffusion of oxygen, nutrients, carbon dioxide, and waste

7. Structures of the Circulatory System
Blood Vessels
Include veins
Carry blood back to the heart, against gravity
Utilize skeletal muscle contractions to help push blood along
Have thin walls and valves to prevent blood from flowing backwards

10. Flow of Blood Through the Heart
Systemic Circulation
Uses the left side of the heart
Pumps oxygenated blood to the body
Includes the coronary arteries that service the heart
Pulmonary Circulation
Uses the right side of the heart
Pumps deoxygenated blood to the lungs

11. Flow of Blood Through the Heart
Vena cava brings deoxygenated blood back to the heart
Blood enters the right atrium
Blood flows through the atrioventricular valves to the right ventricle
Blood flows through the semilunar valves into the pulmonary arteries
Pulmonary arteries take blood to the lungs

12. Flow of Blood Through the Heart
Re-oxygenated blood flows back to the heart in the pulmonary veins
Blood enters the left atrium
Blood flows through the atrioventricular valves to the left ventricle
Blood flows through the semilunar valves and exits the heart through the aorta

15. The Heartbeat
The sinoatrial node (SA node, or pacemaker node) sends an electrical impulse over the atria
Both atria contract, pushing blood into the ventricles, causing a “lub” sound
The atrioventricular node (AV node) picks up the impulse from the SA node
The AV node pauses for a millisecond, then sends the electrical impulse over the ventricles
Both ventricles contract, pushing blood into blood vessels, causing a “dub” sound

17. Blood Pressure Is measured in systolic pressure
Shows the pressure in the arteries when the ventricles contract
- Is measured in diastolic pressure
Shows the pressure in the arteries when the ventricles relax
Is measured with a sphygmomanometer
Written as systolic over diastolic pressure
Average BP = 120/80