1. Circulatory System

2. Circulatory System Consists of:
Heart Blood vessels Blood

3. 5 Functions of the Circulatory System
Carries nutrients from the digestive system to cells.
2. Carries O2 from lungs to cells.
3. Carries waste products to the urinary system.
4. Carries CO2 from cells to lungs
5. Carries immune cells that help fight disease.

4. The Heart Located near the center of the chest
Composed almost entirely of muscle
About the size of a clenched fist
Contracts about 72 times per minute and pumps 70ml of blood with each contraction

5. Pericardium
The heart is enclosed in a protective sac called the pericardium

6. Myocardium Thick layer of muscle
Contractions of the myocardium pump blood through the circulatory system

7. Septum Divides the right and left sides of the heart
On each side of the septum are two chambers
Prevents mixing of oxygen-rich and oxygen-poor blood

8. Atrium Upper chambers of the heart
Right atrium receives oxygen- poor blood from body
Left atrium receives oxygen-rich blood from the lungs

9. Ventricle Lower chambers of the heart Pumps blood out of the heart
Oxygen-rich blood leaves the left ventricle

10. Total of 4 chambers

11. Circulation Through the Body
The heart functions as two separate pumps

12. Pulmonary Circulation
Oxygen-poor blood from the right side of the heart goes to the lungs.

13. In the lungs...
Carbon dioxide leaves the blood and goes into the alveoli of lungs. Oxygen is absorbed into the blood on red blood cells (hemoglobin)

14. Systemic Circulation
Oxygen-rich blood from the left side of the heart goes to the rest of the body.

15. After cycling through the body
Oxygen-poor blood returns to the right side of the heart and the cycle starts over.

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17. 1 8 4 4 4 5 5 6 2 3 7 Superior Vena Cava Pulmonary Artery Pulmonary
Veins
Pulmonary
Veins 5 5 6
Mitral
Valve 2
Pulmonary
Valve
Aortic
Valve 3
Tricuspid
Valve 7
Inferior
Vena Cava

18. Veins bring O2 poor blood from upper part of body
Brings O2-rich blood from left ventricle to entire body 1
O2-poor blood to right lung
O2-poor blood to left lung 8 4 4 4
O2-rich blood from right lung 5
O2-rich blood from left lung 5 6
Lt. Ventricle pushes O2-rich blood to aorta and body 2
O2-poor blood enters the right atrium then right ventricle 3 7
Rt. Ventricle pushes O2-poor blood to right & left lung
Veins bring O2-poor blood from lower part of body

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21. Valves
Flaps of connective tissue between atria and ventricles. Allows for one direction of blood flow.

22. Heartbeat - SA Node Sinoatrial node (SA) = Pacemaker
Small group of cardiac muscle cells
Starts the wave of heart muscle contraction
“Sets the pace”

23. Heartbeat - AV Node Atrioventricular node (AV) Bundle of fibers
Picks up impulses from the SA node and transmits to network of fibers in the ventricles

24. Heartbeat Heartbeat depends on body’s need for oxygen-rich blood
Increase heart beat:
Sympathetic nervous system
Decrease heart beat:
Parasympathetic nervous system

25. Blood Pressure
Contraction of the heart produces a pressure within the circulatory system
The force of blood on the wall of the arteries is known as blood pressure

26. Measuring Blood Pressure
The BP cuff is wrapped around the upper portion of the arm and pumped with air until blood flow in the artery is blocked.
As the pressure is released, 2 numbers are recorded:
Systolic pressure
Diastolic pressure

27. Blood Vessels

28. 3 types of Blood Vessels
Arteries Capillaries Veins

29. Arteries Large vessels Carry blood from heart to tissues of body
Thick walls - need to handle the high pressure

30. Capillaries Smallest blood vessels Walls only one cell thick
Bring nutrients and O2 to tissues and absorbs CO2 and waste from tissues

31. Veins Carry blood from tissues back to heart
Blood in veins do not have oxygen
Walls of veins contain connective tissue and smooth muscle

32. Walls of Blood Vessels
Connective Tissue - elastic, allows for expansion
Smooth Muscle - regulates diameter
Endothelium - layer of cells nearest blood

33. Valves of the Veins Valves in large veins, prevents backflow of blood
Located near or between skeletal muscles
Skeletal muscle contraction forces blood through veins
Prevents blood from accumulating in limbs

34. Lack of exercise - Veins
Veins get out of shape
Valves weaken
Blood pools in veins = varicose veins

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36. Disorders of the Circulatory System - Atherosclerosis
Fatty deposits in walls of arteries
Obstruct blood flow and raise blood pressure
Increase risk of blood clots

37. Disorders of the Circulatory System - Heart Attack
Caused by blocked arteries
Blood cannot get to the heart muscle
Heart muscle begins to die due to lack of O2

38. Disorders of the Circulatory System - Stroke
Blood clot breaks free and blocks a vessel leading to the brain
Brain cells starved of O2 and nutrients
May cause paralysis, loss of ability to speak or death

39. Disorders of the Circulatory System - High Blood Pressure
Blood pressure is the measure of force exerted by the blood on the wall of the arteries
Too much pressure can cause health problems such as heart disease

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