ANATOMY AND PHYSIOLOGY

CARDIOVASCULAR SYSTEM – responsible for the transport of O2 and CO2, nutrients and waste products.

I. Anatomy of the Heart

Location:

N  Apex- left at 5^th intercostals space

N  Base-towards the shoulder at 2^nd rib

Coverings and walls

Pericardium- a double layer sac that encloses the heart

Three layers

[  Epicardium- outer layer

[  Myocardium- middle layer

[  Endocardium- inner layer

Heart Chambers

[  Atria- upper receiving chambers

[  Ventricles- lower pumping chambers

Heart Valves

AV Valves- between atria and ventricles

[  Bicuspid- left AV valve

[  Tricuspid- right AV valve

Semilunar Valves

[  Pulmonic- at the pulmonary trunk

[  Aortic- at the aorta

Cardiac Circulation

[  Coronary arteries- supplies blood to the heart

II. Physiology of the Heart

Conduction System of the Heart

Two types of controlling system

1. Autonomic Nervous System

[  Symphatetic stimulation- increases heart rate

[  Parasymphatetic stimulation– decreases heart rate

2. Nodal System

[  SA Node – atrial contraction

[  AV Node

[  AV Bundle

[  Bundle Branches

[  Purkinje Fibers

CARDIOVASCULAR SYTEM: THE BLOOD VESSELS

Arteries- carries blood away from the the heart

Veins-brings blood back to the heart

Tunics

[  Interna

[  Media

[  Externa

Physiology of Circulation

Arterial Pulse – alternating expansion and recoil of an artery that occurs with each beat of the ventricles

Blood Pressure – pressure the blood exerts against the inner walls of the blood vessels

[  Systolic Pressure- the pressure in the arteries at the peak of ventricular contraction

[  Diastolic Pressure- the pressure when the ventricles are relaxing

Peripheral Resistance- amount of friction encountered by a blood as it flows through the blood vessels

Factors affecting Blood Pressure

[  Neural factors

[  Renal factors

[  Temperature

[  Chemicals

[  Diet

Variations in Blood Pressure

Hypotension- low BP; systolic BP of below 100 mmHg

Hypertension- 140/90 or higher

FLUID AND ELECTROLYTE BALANCE

Fluid Compartments- main location of water within the body

Intracellular Fluid (ICF)- 2/3 of the body fluids, contained within the living cells

Extracellular Fluid (ECF) – 1/3 of the body fluids;all body fluids outside the cells; includes blood plasma, interstitial, CSF and serous fluids

*Very small changes in electrolyte balance, the solute concentration in various fluid compartments cause water to move from one compartment to another

Sodium- the major extracellular cation, important for water balance, conduction of nerve impulse and muscle contraction

Potassium- the major intracellular cation, necessary for the conduction of nerve impulse and muscle contraction