heart is located
the anterior inferior mediastium.
anterior inferior mediastium is the region=
between 2 pleural cavities.
2/3 rds of the hearts mass is where?
to the left of the midline
the base of the heart is where?
just below the second rib and is directed toward the right shoulder.
the apex of the heart lies where?
in the fifth intercostals space and 7-9 cm to the left of the midline directed toward the left hip.
heart is approximately the size of
the owners fist
at birth the hearts size is?
a perfect square of 25mm, height length and width.
a t birth the heart weighs
in an adult the heart measures at
12.5cm long, 9cm wide, and 5 cm deep.
in an adult the heart weighs
left and right atria's function is
each atrium has an
an auricle is a
triangular appendage that helps increase the surface area of the atria when needed to expand.
right and left ventricles function is
the right ventricle is thin and involved in
the left ventricle is thick and involved in
the heart is enclosed and held in place by the
majority of the anterior and half of the posterior of the heart is covered by
this resembles a bag around the heart and consists of fibrous connective tissue
fibrous pericardium prevents
over destention of the heart
fibrous pericardium provides
a tough membrane around the heart and anchors the hearts in the mediastium
serous pericardium forms
a double layer around the heart and is thin and delicate
serous pericardium consists of 2 layers called
parietal serous pericardium and visceral serous pericardium or epicardium
perietal serous pericardium is located
directly d=beneath and fused to the fibrous pericardium
visceral serous pericardium or epicardium is attached to
between the parietal serous and the epicardium is a space called____ , and a fluid called____.
pericardial cavity, pericardial fluid
pericardial fluid functions in preventing what?
friction between the membranes as the heart contracts. there is also about 30 ml of pericardial fluid.
what is pericarditis?
inflammation of the pericardium and with this there is a pericardial fluid build up or extensive bleeding into the pericardium.since pericardium can't stretch it compresses the heart
when the heart compresses it is known as
cardiac tamponade and can result in cardiac failure or if the membrane dries it will cause painful friction or rubbing.
a thin transparent outer layer of the wall. it may have fat deposits
which layer of the heart is the thickest?
the reinforced muscle ridges in the myocardium is called
what is a thin layer of the endothelium overlying a thin layer of connective tissues
the heart valves are former by what?
a fold of the endocardium, making a double layer of endcardium with connective tissues in between.
heart sound heard through a
listening to body sounds
first heart sounds that occurs at the beginning of ventricular systole. its l ow frequency.
first heart sound is caused by
vibrations of AV valves during and after closure. turbulence in the stream of blood as it is ejected through atrial openings.and vibrations in muscle of ventricles as they contract.
second heart sound that occurs at end of ventricular systole as ventricular pressure begins to fall. and is caused by closure of the semilunar valves .it is higher pitched than lubb.
dubb is shorter in duration time than lubb?
3rd and 4th heart sound may be heard with
3heart sound occurs
during or after ventricular contraction. this is due to the tension of the muscle when the blood hits the the ventricles from the atria.
this is common in children and adolescents, rarely audible in people over 30
3rd heart sound
4th heart sound
occurs during atrial contraction.
abnormal sounds due to back flow of blood when valves fail to close completely.
funtional murmur occurs
only during strenuous excursive and are of no threat
organic murmurs indicate
presence of valvular abnormalities
systolic murmur - lubb-shh-dupp
occurs cuz blood flows back int atria from ventricles through av valves
diastolic murmur lubb-dupp-shh
occurs bcd blood back flows into the ventricles from the arteries through semilunar valves
regurgitation cz valves dnt close completely
torturous flow through constricted valves
parasympathetic innervation branches of the
vagus nerve, cranial nerve10
sympathetic innervation is at the
superior, middle, and inferior cardiac nerves
sensory nerves(feedback) are
baroreceptors located in the arch of the aorta and the carotid sinuses end pressure change info. to the medulla of the brain.and other receptors in same area send info. on dissolved oxygen concentrations to the medulla of the brain.
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