Heart
is a hollow muscular organ, located in thoracic cavity between lungs behind sternum.
how many layers of the hearts is there?
3. enodocardium, myocardium, epicardium
Endocardium
innermost layer of the heart. forms lining and folds back onto itself to form the 4 valves. where conduction system is found
Myocardium
thick middle muscle layer of the heart; pumps blood through the circulatory system, made of striated muscle fibers.
epicardium
outermost layer of the heart. (also called the visceral)
pericardium
protective sac enclosing the heart composed of two layers with fluid between (Visceral & Parietal)
Visceral pericardium
the innermost of the two layers of the pericardium. ( Also called the Epicardium)
Parietal pericardium
the tough outermost layer of the pericardium that is attached to the diaphragm and the sternum. also lines the fibrous pericardium.
serous fluid
lubricates the organs and allows them glide without friction. prevents friction as the heart beats.
Superior Vena cava
receives blood from the head and arms and chest and empties into the right atrium of the heart. (basicially the upper body)
Inferior Vena Cava
receives blood from lower limbs and abdominal organs and empties into the posterior part of the right atrium of the heart. (basically lower body)
pulmonary Vein
one of two pairs of vessels carrying oxygenated blood from the lungs to the left atrium of the heart. (the only vein in your body that carries oxygenated blood)
Pulmonary Artery
vessel that carries deoxygenated blood from the right ventricle to the lungs. (the only artery in your body that carries deoxygenated blood)
Right atrium
The upper right chamber of the heart, where deoxygenated blood is received from the vena cava and then sent to the right ventricle.
Right Ventricle
the chamber on the right side of the heart that receives venous blood(oxygen poor) from the right atrium and pumps it into the pulmonary trunk (pulmonary vein)
Left Atruim
left upper portion of the heart; recieves blood rich in oxygen as it returns from the lungs via the left and right pulmonary veins
Left ventricle
the chamber on the left side of the heart that receives arterial blood (oxygen rich blood) from the left atrium and pumps it into the aorta. (thickest chamber in the heart)
The heart is actually _____ sided pump sepereated by ______?
two,septum
The upper chambers of the heart ?
right and left atrium
Lower chambers of the heart
left and right ventricle.
both ____ contract together then ____ ?
Atria , ventricles
what is the purpose of the heart valves?
The valves open and close to let the blood flow in only one direction. prevents backflow of blood in the heart.
Atrioventricular valves
Separate the atria and the ventricles. Right sided tricuspid, left sided bicuspid. (Atrio-Ventricular) between.
Tricuspid valve
valve between the right atrium and the right ventricle. has three cusps
Bicuspid valve
located between the left atrium and left ventricle. 2 cusps. also called the mitral.
semilunar valves
located between the right ventricle and the pulmonary artery and between the left ventricle and the aorta. half- mooned shaped cusps
Pulmonary valve
a semilunar valve between the right ventricle and the pulmonary artery. prevents blood from flowing from the artery back into the heart.
Aortic valve
a semilunar valve between the left ventricle and the aorta. prevents blood from flowing from the aorta back into the heart
Murmurs
abnormal sounds that may be heard during ventricular systole or diastole (contraction and relaxation) cuased by diseases.
what produces heart sounds?
closure of valves.
sound one
due to closure of bi cuspiud (mitral) and tricuspid
sound two
due to closure of aortic & Pulmonic valves
autonomic nervous system (ans)
the part of the nervous system of vertebrates that controls involuntary actions of the smooth muscles and heart and glands. sepereated in two parts sympathrtic and parasymphatetic
Sympathetic nervous system
affects both the atria and the ventricles by increasing heart rate conduction and irritability
Parasympathetic nervous system
affects the atria only by decreasing heart rate, conduction and irritability
Automacity
Ability of the cardiac muscle to intiate a electrical impulse
excitability
ability of a cell membrane to conduct electrical impulses
Conductivity
the ability to conduct an electric current. ( recieve an electrical impulse)
contractility
ability to contract forcefully when stimulated
Depolarization
sodium rushes into neuron through membrane, potassium ruses out; results in a change in charge. ( usualy contraction)
Repolarization
recharging of the myocardial cell from a contracted state back to a resting state. Relaxation
Sa node (sinoatrial node)
primary pacemaker of he heart and has a normal firing rate of 60-100 bpm
internodal pathway
links the sinoatrial node and the atrioventricular node.Path in which impulses travel to signal the atria to contract.
AV junction
av node + bundle of his
Av node
-a back-up node for heart
-40-60/min
bundle of his
a bundle of modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract
Bundle branches
Part of the conduction system of the heart; the electrical signal travels down the interventricular septum. function of which is to conduct the electrical impulse to the purkinje fibers
purkinje fibers
fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract