1. Heart Structure and Function
Circulatory System
Heart Structure and Function

2. Our Goal This Section...
Describe the parts of the heart and how they work together

4. Anatomy of the Heart 4 chambers: 2 atria and 2 ventricles
right side feeds the
pulmonary circuit
left side feeds the
systemic circuit

7. Atria
Receiving chambers
Right Atria accepts blood from the anterior and posterior vena cavae (DEOXYGENATED BLOOD)
Left Atria accepts blood from the pulmonary veins (OXYGENATED BLOOD)

8. Atrioventricular Valves
Structure:
Location:
Function:
How it works:

9. Atrioventricular Valves
Structure: Flaps of tissue
Location: Separate the atria from the ventricles
Function: Ensure no back flow of blood in the heart
How it works: when the blood pressure in the atria is greater then the blood pressure in the ventricles - valves open (atrial contraction) allowing blood to enter the ventricles

10. AV Valves

11. Chordae Tendoneae
Tendons
Attach AV valves to ventricles
Prevent AV valves from inverting when the ventricles contract

12. Ventricles
Contract together to send blood out of the heart
Fill with blood when the atria contract
Right ventricle contracts causing the AV closed and blood enters pulmonary valve - leads to the pulmonary trunk and then pulmonary arteries
Pulmonary arteries take blood to lungs for oxygen
In left ventricle the flow of blood is the same except that the blood enters the aortic valve which leads to the aorta
Semi-lunar valves

13. Pulmonary Valve (Semi-lunar valve
Aortic Valve
(Semi-lunar valve)
Chordae Tendineae

14. Septum
Structure:
Keeps _________________ and _________________ circuits separate

15. Septum
Structure: Muscular wall separating the left and right side of the heart
Keeps pulmonary and systemic circuits separate

16. Coronary Arteries
1st branches of the aorta
Feed heart muscle
Coronary veins take blood back to the vena cava when it enters the right atrium

17. Control of the Heart Sino-atrial (SA) node Atrio-ventricular (AV) node
Right Atrium
Made of special muscles and nerve cells that can contract without stimuli – will continue beating even outside of the body!
SA nodes is along the wall of the atrial chamber
AV node is deeper, close to the AV valve

19. SA Node
AV Node
Causes atrial contraction
Send nerve impulse to the __________________ (causes it to respond)
Nicknamed the ____________________ as it initiates the heartbeat
AV node uses _______________________to stimulate the massive ventricles
Purkinje fibers are nerves that begin at the AV node sending impulses through both _______________________

20. SA Node
AV Node
Causes atrial contraction
Send nerve impulse to the AV node (causes it to respond)
Nicknamed the pacemaker as it initiates the heartbeat
AV node uses PURKINJE FIBERS to stimulate the massive ventricles
Purkinje fibers are nerves that begin at the AV node sending impulses through both ventricles

21. Remember Our Goal...
Describe the parts of the heart and how they work together

22. Our Goal this Section...
Analyse the relationship between heart rate and blood pressure

23. Heart Beat
Double sound caused by the closing of the AV valves followed by the semi-lunar valves.
Electrocardiogram (EKG)

24. Nervous System
SA node is connected to the brain by a nerve.
Brain will signal the SA node through a nerve to accelerate its contraction if more blood is needed in the tissues or blood pressure too low.
Part of brain = medulla oblongata
Autonomic

25. Blood Pressure Low blood pressure can be harmful
Kidneys function is dependent BP
Hypertension: ________________________
Hypotension:_________________________
Body can adjust BP – monitored in the ________________________ of the brain
Arterioles constrict or dilate to raise or lower BP

26. Blood Pressure Low blood pressure can be harmful
Kidneys function is dependent BP
Hypertension: high BP
Hypotension: low BP
Body can adjust BP – monitored in the medulla oblongata of the brain
Arterioles constrict or dilate to raise or lower BP

27. Blood Pressure Force of blood against the blood vessel walls
Greater when the ventricles are contracting (forcing blood through arteries) – SYSTOLIC PRESSURE
Between contractions the blood pressure is lower – DIASTOLIC PRESSURE
Measured along the brachial artery of the arm

29. Blood Pressure 120/80 mmHg is normal
High blood pressure strains tissues being fed by blood
High blood pressure is normal during physical activity
Blood pressure is affected by lifestyle, diet and stress
Plaques can line the insides of arteries and arterioles increasing BP
If plaque block a blood vessel then tissue damage or tissue death may occur
If coronary arteries are blocked then part of heart muscle may die – heart attack

30. Blood Pressure
Heart Beat
Heart Structure