chapter19 heart

What are the functions of the heart

Generating blood pressure

Routing blood pressure

Ensuring one way blood flow

Regulating blood supply

What are the two circuits of the heart and what are their components

Pulmonary - right side, O2 poor, CO2 rich

Systemic- left side, O2 rich, CO2 poor

What are the three layers of tissue around the heart

Epicardium

Myocardium

Endocardium

What are the pericardial sacs

Fibrous pericardium- outer layer, acts as anchor

Serous pericardium- thin transparent,

• parietal pericardium- outer wall of pericardial layer

• Visceral pericardium- covers heart surface

What are the four chambers of the heart

Right atrium

Left atrium

Right ventricle

Left ventricle

AV valve

Prevents back flow into the atria

• right AV valve has 3 cusps (tricuspid)

• left AV valve has 2 cusps (mitral)

Semilunar valves

Control flow into great arteries

• pulmonary- right ventricle- pulmonary trunk

• Aortic- left ventricle- aorta

Ventricles relax is also called

Diastole, repolarization

Pressure drops, semilunar valves close

Av valves open, blood flows from atria to ventricles

Ventricle contraction is also called

Systole, depolarization

Pressure increases, av valves close

Semilunar valves open, blood flows into great vessels

What drains the right margin of the heart

Great cardiac vein

Small cardiac vein

Where do all cardiac vein empty

Coronary sinus

What is angina pectoris

Thoracic pain caused by blood delivery deficiency to the myocardium

What is myocardial infarction

Prolonged coronary blockage

Heart attack

Anatomy of cardiac muscles

Striated

Short

Fat

Interconnected

What joints are found in cardiac muscles

Desmosomes

Gap junction

What’s the purposes of desomosomes

Prevent cells from separating during contraction

What’s the purpose of gap junctions

Allows ion to pass

Pass electrical signals from one cell to another

How much of the cell volume is the mitochondria

25-35%

Are cardiac muscles aerobic or anaerobic

Aerobic

SA node

Pace maker

Spontaneous action potential

AV node

Action potential conducted more slowly

AV bundle

Passes through a hole in cardiac skeleton to reach interventricular septum

Right and left bundle branches

Extend beneath endocardium to right and left ventricles

Purkinje fibers

Large cardiac muscle cells

Many gap junctions

Fast conduction

Absolute refractory period

Cardiac muscles completely insensitive to further stimulation

Relative refractory period

Cells exhibit reduced sensitivity to additional stimulation

P wave

Depolarization of atrial myocardium and signals onset of atrial contraction

QRS complex

Ventricular depolarization and singles onset of ventricular contraction

T wave

Repolarization of ventricles

PQ interval

0.16 seconds

Atria contract and begin to relax

QT interval

0.36 secs

Ventricles contract and begin to relax

What is a cardiac cycle

One complete contraction and relaxation of all four chambers

Electrical cardiac cycle

Cardiac action potential

Increases ca2+

Mechanical cardiac cycle

Contraction and generation of pressure

Blood always moves from

Fisher to lower pressure

What is blood pressure

Force area exerted on the wall of a blood vessel by the blood

What 3 things affect blood pressure

Cardiac contractility- strength of contraction

Peripheral resistance- diameter of blood vessel

Blood volume

what is caused by ventricular contraction

the ab valve close and then the semilunar valves open

when the pressure in the ventricles becomes lower then the pressure in the atria

the av valves open