❤ Flashcards
cardiac muscle cells are branched and may be called
muscle fibers
cardiac muscle cells have many mitochondria the function of which is to produce
atp
units of contraction of cardiac muscle fibers are
sarcomeres
the striations of cardiac fibers are the result of the arrangement of contracting protiens
myosin and actin
electically and action potential is what
depolarization followed by repolarization
an action potential involves the entry of what into the muscle fiber followed by the exit of what from the muscle fiber
sodium ions and potassium ions
cardiac muscle cells generate their own action potential which means that they do not require what in order to contract
nerve impulses
the electrical impulses of cardiac myocytes spread quickly to adjacent cells because of the presence of what at the end of the cells
intercalated discs
the speed of the electrical impulses ensures that in one heartbeat the two - will contract first followed by the simultaneous contraction of the two -
atrias and ventricles
cardiac muscle is an endocrine tissue because some cells produce a hormone called
atrial natriuretic peptide (ANP)
the stimulus for anp secretion is
strectching of the heart muscle
the effect of anp on the kidneys is to decrease the reapsorption of - which in turn increases the excretiin of -
sodium ions. water
the effect of anp on vascular smooth muscle is to cause
vasodilation
anp also stimulates the conversion of white adipocytes to brown adipocytes so that fats are not stored but rather their energy is released in the form of
heat
what is the function of the heart
pump blood
the heart is located in the mediasternum which is the area between the
lungs in the thoracic cavity
what is the organ directly below the heart
diaphragm
how many layers of pericardial membranes are around the heart
3
the outermost layer is called what and it isnmade up of what kind of tissue
fibrous pericardium and fibrous connective tissue
the serous membrane that lines the fibrous pericardium is called the
parietal pericardium
the serous membrane that is on the surface of the heart muscle is called
visceral pericardium or the epicardium
the function of the serous fluid produced by the serous layers is to what as the heart beats
prevent friction
the heat has how many chambers
4
what are the upper two chambers of the heart called
atria
what are the two lower chambers of the heart called
ventricles
what is the tissue that forms the walls of the chamber of the heart
myocardium or cardiac muscle
the chambers of the heart are lined with simple squamous epithelum called what
endocardium
the endocardium covers what
the valves of the heart
what is the most important phyiscal characteristic of the endocardium is that it is
very smooth and prevents abnormal clotting in the chambers of the heart
which pair of chambers have thicker walls
ventricles
the wall of the myocardium between the two atria is the
interatrial septum
the wall of the myocardium between the two ventricles is the
interventricular septum
which chamber of the heart has superior and inferior caval veins and returns blood from the body
right atrium
which chamber of the heart has pulmonary veins and returns blood from the lungs
left atrium
which chamber of the heart has pulmonary artery and takes blood to the lungs
right ventricle
which chamber of the heart has a arota and takes blood to the body
left ventricle
prevents back flow of the blood to the right atrium when the right ventricle cintracts
tricuspid valve
between the right atrium and right ventricle
tricuspid valve
between the left atrium and left ventricle
mitral valve
prevents backflow of blood to the left atrium when the left ventricle contracts
mitral valve
at the junction of the right ventricle and the pulmonary artery
pulmonary semilunar valve
prevents backflow of blood to the right ventricle when the ventricle relaxes
pulmonary semilunar valve
at the junction of the left ventricle and the aorta
aortic semilunar valve
prevents backflow of blood to the left ventricle when the ventricle relaxes
aortic semilunar valve
the papillary muscles are columns of what that project into each what
myocardium / ventricle of the heart
the chordae tendineae are strands of what kind of tissue
fibrous connective tissue
where does the chordae tendineae extend from
the papillary muscles to the flaps of the av valvues
the heart is what kind of pump
double
the left side of the heart recieves blood from where
lungs and pumps it to the body
the right side of the heart recieves blood from the what
body and pumps blpod back to the lungs
what is the order of blood flow
left atrium left ventricle aorta body superior and inferior caval veins right artium right ventricle pulmonary artery lungs pulmonary veins
The purpose of the coronary vessels is to what
circulate bloid throughout the myocardium 💛
the most important substance in the blood is
oxygen
the right and left coronary arteries are branches of the
aorta
the coronary sinus is formed by the union of cornonary veins and it returns blood from the myocardium to the
right atrium
what will happen to a part of the heart muscle that is deprived of its bloos supply
heart muscle cells begin to die
what is a possible cause that the heart muscle can be deprived of blood supply
blood clot
the cardiac cycle is a term for the sequence of events in
one heartbeat
the term systole
contraction
the term diastole
relaxation
the cardiac cycle normally creates how many heart sounds
2
the first sound is caused by the closure of the
av values
the second sound is is caused by the closure of the
semilunar valves
an extra sound during in the cardiac cycle is called a
heart murmur
must the heart recieve nerve impulses to cause contraction
no
what do nerve impulses regulate
the rate of contaction
name the parts of the conduction pathway that brings about ventricular systole
bundle of his bundle branches purkinje fibers
irregular heartbeat
arrhythmia
most serious arrythmia
fibrillation
normal range of resting heart rate for a healthy adult
60-80 beats per minute
vital sign that is a measure of heart rate
pulse
name the parts of the conduction pathway that brings about atrial systole
sa node and av node
cardiac centers and located in the
medulla of the brain
what are the two cardiac centers called
accelerator and the inhibiting center
sympathetic nerves to the heart transmits impulses that what (decrease or increase) heart rate
increase
parasympathetic nerves to the heart are the what nerves and what do they do
vagus and decrease heart rate
receptors that detect changes in blood pressure are called what and where are they located
pressoreceptors and are located in the cartoid sinus and aortic sinus
receptors that detect changes in oxygen level of blood are called what and where are they located
chemoreceptors and are located in the carotid body and aortic body
sensory nerve for the carotid sinus and body is the
glossopharyngeal
sensory nerve for the aortic sinus and body is the
vagus
the hormone that increases heart rate and force of contraction in stressful situations is
epinephrine secreted by the adrenal medulla
natural pacemaker of the heart
sa node
first branches of the ascending aorta
coronary arteries
largest artery of the body
aorta
narrowing of the valvue
stenosis
chambers of the heart that recieve blood from veins
right and left atria
chambers of the heart that recieve blood from veins
right and left atria