Structure of Heart & Actions of the Heart
1. List the chambers of the heart.
Right atrium, left atrium, right ventricle, left ventricle

2. What vessels bring blood to the right atrium?
The super vena cava, inferior vena cava, and coronory sinus.

3. What vessels bring blood to the left atrium?
Pulmonary veins.

4. What is the function of the valves of the heart?
It controls the flow of blood.

5. What events make up the cardiac cycle?
The atria contracts and the ventricle relaxes. Then the atria relaxes and the ventricle contracts. Then both the atria and the ventricle relax for a brief interval before the atria contracts again. This cycle is the cardiac cycle.

6. What produces the heart sounds heard with a stethoscope?
A heart beat is often said to sound like “lubb-dupp” which occurs when the valves in the heart tissue. The “lubb” occurs during ventricle systole and “dubb” occurs during ventricle diastole.

7. What structures can be assessed by heart sounds?
If there is a murmur sound, the valvular cusps are not completely closing and blood is leaking.

8. Trace an impulse through the cardiac system.
SA Node, AV Node, Bundle of His, and Purkinje Fiber.

9. How is the heart affected by the following: potassium, calcium, and temperature?
An increase in potassium leads to a decrease in the heart rate. An increase in calcium leads to an increase in the heart rate while a decrease in calcium leads to a decrease in the heart rate. An increase in temperature increases the heart rate while a decrease in temperature decreases the heart rate.

Blood Vessels
10. Describe the structure of the arteries.
Arteries are strong elastic vessels that carry blood away from the heart under high pressure. Wall of the arteries consist of three layers. The three layers are the tunica interna, tunica media, and tunica extrema. Tunica interna is the inner layer that is made of simple squamous epithelium. Tunica media is the middle layer that has smooth muscle fibers that encircles the tube/thick layer elastic connective tissue. Tunica extrema is an outer layer that is made of relatively thin connective tissue.

11. How is the structure of arteorioles different from that of arteries?
Arteries are very strong elastic vessels that carry blood away from the heart under high pressure. Arteorioles are vessels that subdivide into thinner tubes and branches.

12. What determines the density of capillaries within tissue?
The rate of metabolism within the tissue reflect the capillary’s density.

13. How is the distribution of blood in the capillaries regulated?
Precapillary sphincters regulate the distribution of blood.

14. What is blood pressure?
Force exerted by blood on the walls of vessels.

15. What cardiac events are related to systolic and diastolic arterial pressure?
Systolic is the maximum pressure due to ventricle contraction. Diastolic is low pressure due to ventricle relaxation.

16. What is a pulse?
Swelling of blood vessels due to pressure.

17. How does each of these factors influence blood pressures: Heart action, blood volume, peripheral resistance, and viscosity.
Heart action determines the rate of flow. Blood volume can affect the pressure, less blood means a decreased flow. Peripheral resistance means friction and a slower blood flow,. Viscosity means the thicker the blood, the more increase in pressure.

18. Discuss the mechanical, neural,. and chemical factors that affect cardiac output.
Mechanical: Longer the fibers the stronger the contraction.
Neural: Cardiac center in brain that sends impulses to the SA Node.
Chemical: Natural endorphins cause an increase in heart rate.

19. How is peripheral resistance regulated?
Peripheral resistance is regulated by alternating constriction and dilation of blood vessels.

Path of Circulation
20. How do the pulmonary and systematic circuits differ?
Pulmonary pumps blood from heart to lungs. Systematic pumps blood from the heart to the body.

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