2. Basic Definitions Arteries carry blood away from the heart
Veins carry blood back to the heart
Arterioles = small arteries
Venules = small veins
Capillaries: smallest vessels where nutrient, waste and gas exchange take place. So narrow that blood cells proceed through single file. Walls are a single layer of epithelium.

3. Summary Concepts
The human heart has four chambers left and right atria, left and right ventricles
The human heart has four valves two atrioventricular valves (tricuspid and mitral) two semilunar valves (aortic semilunar and pulmonary semilunar)
Pulmonary circulation: starts as blood leaves the right ventricle and enters the pulmonary trunk -> lungs -> pulmonary veins -> left atrium
Systemic circulation: starts as blood leaves the left ventricles -> aorta -> head, arms, legs, body -> vena cava -> right atrium Coronary circulation: provides blood to the heart muscle (myocardium). Aorta -> coronary arteries -> heart muscle -> cardiac veins -> vena cava.

4. The Heart and the Pulmonary Circulation

5. Subclavian artery
Left carotid artery
Superior vena cava
Brachiocephalic artery
Aortic arch
Pulmonary arteries
Pulmonary veins
Pulmonary trunk
left atrium
Right Atrium
Coronary arteries
Cardiac veins
Left Ventricle
Right ventricle
Inferior vena cava

6. Valves and Conduction Fibers of the Heart

7. Atria: receive blood from principle
veins and assist in filling the ventricles
Ventricles: pump blood under high
pressure into pulmonary trunk and
the aorta.
Left Atrium
Aortic
Semilunar
Right Atrium
Pulmonary
Semilunar
Bicuspid
(mitral)
Tricuspid
Left Ventricle
Right Ventricle

8. Tissues of the Heart
Pericardium: serous membrane sack surrounding the heart
Epicardium: serous membrane on outer surface of the heart
Myocardium: muscle of the heart
Endocardium: membrane lining the interior of the heart
Chordae tendonae: “heart strings” that guide the atrioventricular valves.
Papillary muscle: small muscles that anchor the chordae tendonae to the ventricular walls.

9. Heart Valves are passive and move
According to pressure gradients
(like a loose screen door in a breeze)
Atrioventricular
Semilunar
Aorta
Superior
Vena Cava 8 7
Pulmonary
trunk 4
Pulmonary
Vein 3 5 1 6 2
Inferior
Vena Cava
video

10. The Cardiac Cycle Diastole: period of relaxation
And ventricular filling
Atrial Systole: atria contract
force additional blood into
the ventricles.
Ventricular Systole: ventricles
contract and force blood into
pulmonary trunk and aorta.

11. Purkinje Fibers
Conduction System Video

12. Electrical Recovery of MyocardiumP Q S
Electrocardiogram

13. Cardiac Output
Stroke Volume (mL/beat) X Heart Rate (beats/min) = Cardiac Output (mL/min)
75 mL/beat X 72 beats/min. = mL/min.
Questions
Do athletes have greater or lesser demands for oxygen than non-athletes?
Do athletes have greater or lesser resting heart rates than non-athletes?
How do you reconcile this observation?
Affects of Athletic Training
- Stroke volume increases, heart rate decreases
95 mL/beat X 60 beats/min. = mL/min.
Even though the athlete has a lower resting heart rate, s/he has a greater
Cardiac Output than the untrained person.

14. Cardiac Center in the Medulla
Controls two nerves that lead to the heart 1. accelerator nerve (sympathetic) *acts on the sinoatrial node and ventricles *increases heart rate using norepinephrine 2. vagus nerve (parasympathetic) *acts on the sinoatrial node *decreases heart rate using acetylcholine

15. Regulation of Heart Rate Sensory Inputs
Proprioceptors (Am I moving more?)
Baroreceptors (Is my blood pressure low?)
Chemoreceptors (Is my CO2 high or O2 low?)
Cardiac Center (medulla)
Vagus nerve
Sensory
nerves
Proprioceptors
Motor Output
Accelerator nerve (sympathetic) (releases norpepinephrine) increase rate and force
Vagus nerve (parasympathetic) decrease rate
Accelerator nerve
Baroreceptors and
Chemoreceptors in
the carotid and aortic
arteries

16. Arteries = elastic elements Veins = capacitance elements
compliant
valves
skeletal muscles

17. = Resistance Vessels

18. Arterioles and pre-capillary
Sphincters are muscular
constrict  add resistance
dilate  reduce resistance
Large arteries are elastic
absorb kinetic energy
store potential energy
Each organ has its own set of
Arterioles, and capillary beds
Which may be dilated or constricted

20. 1. Capillary exchange by diffusion
The microcirculation
1. Capillary exchange by diffusion
Vitamins
nutrients
CO2
wastes O2

21. Capillary exchange by bulk flow Starling hypothesis
- capillaries have low permeability to protein (osmotic effect)
- hydrostatic pressure decreases as blood passes through
Net outward pressure = 11 mmHg
Net inward pressure = -9 mmHg

22. Formation of Lymph

23. Edema
Alcoholism
Elephantiasis