Circulation and the heart Topical outline

I-Location of the heart I-Location of the heart II-Structure of the heart II-Structure of the heart Division of the heart Division of the heart III-Function of the heart III-Function of the heart

Circulation Circulation The continuous one way circuit of blood through the body in the blood vessels is known as the circulation. The continuous one way circuit of blood through the body in the blood vessels is known as the circulation.

Location of the heart The heart is slightly bigger than a person's fist. This organ is located between the lungs in the center and a bite to the left of the midline of the body. The heart is slightly bigger than a person's fist. This organ is located between the lungs in the center and a bite to the left of the midline of the body.

Structure of the heart The heart is a hollow organ, with walls formed of three different layers The heart is a hollow organ, with walls formed of three different layers

Function Lines the interior of the chambers and covers the heart valves Description Thin smooth layer of epithelial cell Location Innermost layer of the heart wall Endocardium Contracts to pump blood into the arteries Thick layer of cardiac muscle Middle layer of the heart wall Myocardium Covers the heart and forms the visceral layer of the serous pericardium Thin serous membrane Outermost layer of the heart layer of the heartEpicardium

Division of the heart Health care professional often refer to the right heart and the left heart, because the human heart is really a double pump. The right side pumps blood low in oxygen to the lungs through the pulmonary circuit. Health care professional often refer to the right heart and the left heart, because the human heart is really a double pump. The right side pumps blood low in oxygen to the lungs through the pulmonary circuit.

The left side pumps oxygenated blood to the remainder of the body through the systematic circuit. Each side of the heart is divided into two chambers The left side pumps oxygenated blood to the remainder of the body through the systematic circuit. Each side of the heart is divided into two chambers

Chambers of the heart Chambers of the heart

FunctionlocationChamber Receives blood from the vena cava and the coronary sinus; pumps blood into the right ventricle Upper right chamber Right atrium Receives blood from the right atrium and pumps blood into the pulmonary artery, which carries blood to the lungs to be oxygenated. Lower right chamber Right ventricle

Functionlocationchamber Receive oxygenated coming back to the heart from the lungs in the pulmonary veins; pump blood into the left ventricle Upper left chamber Left atrium Receive blood from the left atrium and pumps blood into the aorta to be carried to tissues Lower left chamber Left ventricle

Blood supply to the myocardium the main arteries that supply blood to the muscle of the heart are the right and left coronary arteries the main arteries that supply blood to the muscle of the heart are the right and left coronary arteries

Valves of the heart FunctionDescriptionLocationValve Prevents blood from flowing back up into the right atrium when the right ventricle contracts (systole) Valve with three cusps: tricuspid valve Between the right atrium and right ventricle Right AV valve Prevents blood from flowing back up into the left atrium when the left ventricle contracts (systole) Valve with two cusps: bicuspid or mitral valve Between the left atrium and left ventricle Left AV valve

FunctionDescriptionLocationValve Prevents blood from flowing back into the ventricle when the right ventricle relaxes (diastole) Valve with three half- moon shaped cusps At the entrance to the pulmonary artery Pulmonary semilunar valve Prevents blood from flowing back into the left ventricle when the left ventricle relaxes (diastole) Valve with three half- moon shaped cusps At the entrance to the aorta Aortic semilunar valve

Function of the heart Cardiac cycle Cardiac cycle Blood is squeezed through chamber by a heart muscle contraction that begins in the thin – walled upper chambers, the atria and is followed by a contraction of the thick muscle of the lower chambers, the ventricles. This active phase is called systole, and in each case, it is followed by a resting period known as diastole. Blood is squeezed through chamber by a heart muscle contraction that begins in the thin – walled upper chambers, the atria and is followed by a contraction of the thick muscle of the lower chambers, the ventricles. This active phase is called systole, and in each case, it is followed by a resting period known as diastole.

One complete sequence of heart contraction and relaxation is called cardiac cycle. Each cardiac cycle represents a single heart-beat. At rest, one cycle takes an average of 0,8 seconds One complete sequence of heart contraction and relaxation is called cardiac cycle. Each cardiac cycle represents a single heart-beat. At rest, one cycle takes an average of 0,8 seconds

Cardiac output-volume pumped by each ventricle per minute Cardiac output-volume pumped by each ventricle per minute 1-Stroke volume- amount pumped with each beat 1-Stroke volume- amount pumped with each beat 2-Heart rate- number of beats per minute 2-Heart rate- number of beats per minute

B-Heart's conduction system B-Heart's conduction system 1-Sinoatrial node (pacemaker)- at top right atrium 1-Sinoatrial node (pacemaker)- at top right atrium 2-Artioventriclar node- between atria and ventricles 2-Artioventriclar node- between atria and ventricles 3-Atrioventricular bundle (bundle of His) – at top of interventricular septum 3-Atrioventricular bundle (bundle of His) – at top of interventricular septum

a-Bundle branches- right and left, on either side of septum a-Bundle branches- right and left, on either side of septum b-Purkinje fibers- branch through myocardium of ventricles b-Purkinje fibers- branch through myocardium of ventricles

C- Control of the heart rate C- Control of the heart rate 1- Autonomic of nervous system a-Sympathetic system- speeds heart rate b-Parasympathetic system-slows heart rate through vagus nerve 1- Autonomic of nervous system a-Sympathetic system- speeds heart rate b-Parasympathetic system-slows heart rate through vagus nerve

2-Variations in heart rates 2-Variations in heart rates a- bradycardia-slower rate than normal: less than 60 beats| minute d- tachycardia-faster rate than normal: more than 100 beats| minute c-sinus arrhythmia- related to breathing changes d- tachycardia-faster rate than normal: more than 100 beats| minute c-sinus arrhythmia- related to breathing changes d-premature beat- extra systole d-premature beat- extra systole

D- heart sounds D- heart sounds 1- normal 1- normal a-"lubb"-occurs at closing of artrioventricular valves a-"lubb"-occurs at closing of artrioventricular valves b-"dupp “ -occurs at closing of semilunar valves b-"dupp “ -occurs at closing of semilunar valves 2- abnormal-murmur 2- abnormal-murmur An abnormal sound is called a murmur and is usually due to faulty action of a valve fails to close tightly and blood leaks back, a murmur is heard An abnormal sound is called a murmur and is usually due to faulty action of a valve fails to close tightly and blood leaks back, a murmur is heard

IV- in The elderly 1-common variations include: 1-common variations include: a- decrease in heart size, strength of muscle contraction, flexibility of valves and cardiac out put a- decrease in heart size, strength of muscle contraction, flexibility of valves and cardiac out put b-abnormal rhythms, temporary failure of conduction system b-abnormal rhythms, temporary failure of conduction system

V- Maintaining heart health Prevention of heart ailments is based on identification of cardiovascular risk factors and modification of those factors that can be changed. Prevention of heart ailments is based on identification of cardiovascular risk factors and modification of those factors that can be changed. Risk factors that cannot be modified include the following: Risk factors that cannot be modified include the following: -Age. The risk of heart disease increases with age. -Age. The risk of heart disease increases with age. -gender.men have greater risk than women -gender.men have greater risk than women -hereditary -hereditary

Risk factors that can be changed include the following smoking, which leads to spasm and hardening of the arteries smoking, which leads to spasm and hardening of the arteries physical inactivity. lack of exercise weakens the heart muscle and decreases the efficiency of the heart physical inactivity. lack of exercise weakens the heart muscle and decreases the efficiency of the heart over weight increases the risk over weight increases the risk high blood pressure (hypertension) damages heart muscle high blood pressure (hypertension) damages heart muscle

diabetes and gout. both diseases cause damage to small blood vessels diabetes and gout. both diseases cause damage to small blood vessels efforts to maintain a healthy heart should include having regular physical examinations and minimizing the risk factors. efforts to maintain a healthy heart should include having regular physical examinations and minimizing the risk factors. Heart studies using a stethoscope, ECG or EKG. Heart studies using a stethoscope, ECG or EKG.

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