1. The Circulatory System
Notes
Chapter 37
Section 1
The Circulatory System
System.ppt/

2. Functions of the Circulatory System
Brings blood containing oxygen, nutrients, and hormones to cells
Transports CO2 and other wastes away from cells

3. Functions Continued Fights infection Regulates body temperature
Helps stabilize pH and ionic concentration of body fluids.

4. Circulatory System Components Heart Blood Vessels Arteries Veins
Capillaries

5. The Heart A muscular pump Moves blood through the body
Is suspended in the pericardial sac
Aorta
Left pulmonary artery
Left atrium
Left pulmonary
veins
Left ventricle
Superior vena
cava
Right pulmonary
Right atrium
Right ventricle
Inferior vena cava
Composed of four chambers
Divided into right and left halves
Made up of cardiac muscle cells

6. Pericardium Protective sac of connective tissue Surrounds the heart
Filled with
fluid

7. (Inner surface of myocardium)
(heart muscle)
shown in red
Epicardium
(Outer surface
of myocardium)
Endocardium
(Inner surface of myocardium)
The muscle of the heart
Strong and thick
Composed of spontaneously contracting cardiac muscle fibers
Can conduct electricity like nerves
It’s blood supply comes from the coronary arteries

8. Structures of the Heart
Chambers
Atria- (2) upper chambers
Thin walled
Receive blood from veins
Send blood to ventricles
Ventricles- (2) lower chambers
Thick walled
Receive blood from atria
Pump blood out through arteries
Septum
Pulmonary valve
Right atrium
Tricuspid valve
Right ventricle
Left atrium
Aortic valve
Mitral valve
Left ventricle
Septum
Wall that divides heart into right and left halves

9. Structures of the Heart
Valves
Prevent backflow of blood
Keep blood moving in one direction
Valves seen from above
Chordea tendinea
Pulmonary
valve
Tricuspid valve
Pulmonary veins
Mitral valve
Left atrium
Pulmonary valve
Aortic valve
Right atrium
Between the chambers
At junctions of artery and chamber

10. Structures of the Heart
Chordae tendinease
“Heart strings”
Cord-like tendons
Connect papillary muscles to tricuspid and mitral valves
Prevent inversion of valve
Papillary muscles
Small muscles that anchor the cords
Papillary muscle

11. Cardiac Cycle
Refers to all of the events from the beginning of one heart beat to the beginning of the next heart beat
When cardiac muscle contracts it does so as a single unit, creating a heart beat
One heartbeat - a cardiac cycle - consists of two parts called systole and diastole

12. Cardiac Cycle
Diastole is the period of time when the heart relaxes after contraction
Oxygenated blood from the lungs fills the left atrium
Deoxygenated blood from other parts of the body fills the right atrium.
At the end of the diastole, the atria contract, starting the Systole

13. Cardiac Cycle
The term systole is synonymous with contraction of a muscle.
Atrial systole is the contraction of the heart muscle of the left and right atria. Both atria contract at the same time, sending blood into the corresponding ventricle
Ventricular systole is the contraction of the muscles of the left and right ventricles, which contract at the same time.

14. Cardiac Cycle
During systole the ventricles contract, forcing the blood into the pulmonary artery to be re-oxygenated in the lungs, and into the aorta for systemic distribution of oxygenated blood

15. Cardiac Cycle Heart Sounds
“Lub”- sound- due to closure of the atrioventricular valves (mitral and tricuspid)
“Dub”- sound- due to closure of the aortic valve and pulmonary valve
Two normal heart sounds with each heart beat
described as a…..

16. Cardiac Cycle Heart Rate - count of each heart beat
On average, a heart beats 72 times a minute when at rest
Usually it is calculated as number of contractions of heart (heart beats) in one minute and expressed as "beats per minute" (bpm).
The pulse is the most straightforward way of measuring the heart rate
Heart rate is controlled by nervous system
Hearse on an emergency

17. Cardiac Cycle
Sympathetic division increases heart rate
Parasympathetic division decreases heart rate
Heart rate increases when more food and oxygen are needed by the cells, or when under stress
Resting heart rate can be significantly lower in athletes

18. Cardiac Cycle
An electrocardiogram abbreviated as EKG or ECG is a test that measures the electrical activity of the heartbeat or one cardiac cycle.

19. Cardiac Conduction System
Why don’t the atria and ventricles contract at the same time?
Inefficient…. Blood would not be moved in one direction, some would flow backwards

20. Cardiac Conduction System
Includes:
SA node
AV node
Bundle of His
Purkinje fibers
Purkinje fibers

21. Cardiac Conduction System
Sinoatrial Node (SA node)
Located high on the right atrium.
Pacemaker of the heart.
Causes the wave of contractions in the atria.
Sending blood into the ventricles

22. Cardiac Conduction System
Atrioventricular Node (AV node)
Located in the interatrial septum close to the tricuspid valve
Carries the electrical impulse from the SA node to fiber bundles in the ventricles.
This causes the ventricles to contract
The location of nerve fiber bundles cause the ventricles to contract from the apex (bottom) up squeezing blood up and out

23. Pathway of Circulation
Oxygen-poor blood draining from the body through veins into the superior and inferior vena cava flows to the right atrium, through the tricuspid valve, and into the right ventricle.
As the right ventricle contracts, oxygen-poor blood passes through the pulmonary valve into the pulmonary arteries and on to the lungs to receive oxygen.

24. Pathway of Circulation
Oxygen-rich blood from the lungs enters the heart through the pulmonary veins, passing into the left atrium.
Then through the mitral valve to the left ventricle. Contraction of the left ventricle forces blood through the aortic valve into the aorta.
Various arteries branch off from the aorta to supply blood to all parts of the body.

25. Pathway of Circulation
Nutrients pass into tissues
Waste products filter back
Blood pumped out of
heart into arteries,
which branch into
smaller and smaller
vessels until blood flows
into capillaries
Blood returns to the
heart through the veins
Heart
Capillary
network
Arteries branch into smaller and smaller vessels (arterioles)
They eventually become capillaries, which supply blood to all body parts
Capillaries merge into (venuoles) which join into veins and carry blood back to the heart.

26. Cardiovascular Circuits
Pulmonary Circuit
Systemic Circuit
Lung
Pulmonary
vein
Aorta
Left
atrium
ventricle
artery
Right
Vena
cava
oxygen-poor blood
oxygen-rich blood

27. Pulmonary Circulation
Takes place on the right side of the heart.
Pumps blood low in oxygen to the lungs to pick up oxygen and return to heart

28. Systemic Circulation Takes place on left side of heart
Oxygenated blood is pumped to the body cells thru the aorta and other arteries
Blood low in oxygen returns to the heart

29. Coronary Circulation
The coronary circulation consists of the blood vessels that supply blood to, and remove blood from the heart muscle itself.
Although blood fills the chambers of the heart, the muscle tissue of the heart is so thick that it requires coronary blood vessels to deliver blood deep into the myocardium.

30. Coronary Circulation
The vessels that supply blood high in oxygen to the myocardium are known as coronary arteries.

31. Check This Out
This has a lot of good info