heart Flashcards
Transports O2, CO2,nutrients, waste
products and other
substances
Cardiovascular System:
MAIN FUNCTION
carries blood to &
from the lungs
Pulmonary circulation
carries blood to &
from the diff. body
tissues except the
lungs
Systemic circulation
the hollow, cone-
shaped muscular organ
which pumps blood
into the pulmonary
and systemic
circulation.
THE HEART
Size of the heart
size of a
clenched fist
Location of the heart
mediastinum
the pointed end of
the heart which rests on
the diaphragm & is
directed anteriorly,
inferiorly & to the left
apex:
the uppermost,
broad, posterior surface
of the heart
base:
a triple-layered
sac w/c
surrounds &
protects the
heart
PERICARDIUM
the superficial, outer layer w/c
directly attaches to the diaphragm
is made of strong fibrous
connective tissue
fibrous pericardium
its keeps the heart from
overstretching or overfilling with
blood & holds the heart in place at
the mediastinum
fibrous pericardium
a double-layered membrane
sandwiched bet. the fibrous
pericardium & the heart
serous pericardium
the deeper layer of the pericardium
serous pericardium
the outer layer of the serous pericardium
parietal pericardium
adheres to the inner surface of
the fibrous pericardium
parietal pericardium
the inner layer of the serous
pericardium
visceral pericardium
also called epicardium
considered part of the heart
wall
visceral pericardium
adheres tightly to the surface
of the heart
visceral pericardium
the space
bet. the parietal & visceral
pericardium
pericardial cavity:
occupies the
pericardial cavity; the serous
fluid produced by the
epithelial cells of the serous
pericardium w/c prevents
friction as the heart beats
pericardial fluid:
contains blood vessels that supply the
myocardium
Epicardium
covered with adipose tissue
Epicardium
the external layer of the heart wall
Epicardium
the visceral pericardium
Epicardium
the middle, muscular layer w/c forms
the bulk (95%) of the heart wall
Myocardium
made up of cardiac muscle tissue
Myocardium
responsible for the pumping
action/contraction of the heart
Myocardium
located deep to the myocardium
Endocardium
made up of simple squamous epithelium
Endocardium
provides a smooth lining for the
chambers of the heart & covers the valves
of the heart
Endocardium
minimizes the surface friction as blood
passes through the heart
Endocardium
is continuous with the endothelial
lining of the large blood vessels
attached to the heart
Endocardium
the tissue that makes up the heart’s
myocardium
CARDIAC MUSCLE
muscle fibers have the same
arrangement of actin & myosin
myofilaments & Z lines as skeletal
muscle
CARDIAC MUSCLE
what does muscle fibers have in the cardiac muscle?
single,
centrally-located nuclei
its fibers of the cardiac muscle are not
cylindrical but are arranged in a
latticework
are irregular transverse thickenings of
the sarcolemma that connect the ends
of cardiac muscle fibers to one another
intercalated disks:
are highly folded to increase contact
between cells thereby preventing them
from pulling apart
intercalated disks:
allow action potential to spread from
one cell to another
intercalated disks:
contract in response to its own
pacemaker cells that initiate an impulse
spontaneously & repetitively even w/o
external neurohormonal control
autorhythmicity
refers to the contraction of a heart
chamber during depolarization of the
myocardium
systole
relaxation of a heart
chamber during repolarization of the
myocardium
diastole
when systole happends, the heart chamber is
____ & its contents emptied due to
high pressure from the contraction
squeezed
when diastole happends, heart chamber____ as a result of low pressure in
the chamber
fills
with blood
enlargement or increase in
muscle mass as a result of increased
workload
hypertrophy
atrium
Atria
pumps their collected blood into the
ventricles
Atria
the two
superior receiving/collecting chambers of
the heart
right atrium & left atrium
hormone produced by the cells of the
atria;
atrial natriuretic peptide (ANP)
___- due to high blood volume or blood
pressure; effect is _____ to low blood volume & BP
stretching of atrial
walls & renal excretion of
Na+
collects blood from the systemic
circulation
Right Atrium
What are the 3 veins of right atrium?
superior vena cava, inferior vena cava, coronary sinus
collected blood is pumped to the right
ventricle when it contracts
Right Atrium
collects blood from the lungs through the
4 pulmonary veins
Left Atrium
the thin partition between the right &
left atria
Interatrial septum
the two
inferior chambers of the heart
right ventricle & left ventricle
an oval depression on the
interatrial septum
fossa ovalis
the two
inferior chambers of the heart
right ventricle & left ventricle
after pumping the eject blood of the VENTRICLES, it will go to the?
arteries
the pumps that eject blood into the
arteries
Ventricles
propels blood out of the heart into the
circulation
Ventricles
receives blood from the right atrium &
pumps it into the lungs, through the pulmonary
arteries
Right Ventricle
thickest chamber of the heart
Left Ventricle
receives blood from the left atrium &
pumps it into the systemic circulation
through the aorta
Left Ventricle
the partition between the right & left
ventricles
Interventricular septum
receives de-oxygenated blood from areas
above the heart & empty it to the right
atrium
Superior vena cava
brings de-oxygenated blood mostly from
the parts below the heart to the right
atrium
Inferior vena cava
four (4) veins that carry oxygenated
blood from the lungs to the left atrium
Pulmonary veins
exits from the right ventricle and splits to
give rise to the two (2) pulmonary
arteries
Pulmonary trunk
brings de-oxygenated blood from the
right ventricle to the lungs for
oxygenation
Pulmonary arteries
the only artery w/c carries oxygen-poor
blood
Pulmonary arteries
largest artery in the body
Aorta
exits from the left ventricle & carries
oxygenated blood to the systemic
circulation
Aorta
the remnant
of the ductus arteriosus
ligamentum arteriosum
ensure the one-way flow of blood by
opening to let blood through and
then closing to prevent its
regurgitation or backflow
VALVES of the Heart
pressure changes in the heart
chambers cause these cusps to open &
VALVES of the Heart
consists of 2 or 3 cusps or (___) of the valves of the heart
leaflets
located between the atria & the
ventricles on each side
Atrioventricular (AV) Valves
prevents backflow of
blood from left ventricle into
left atrium during ventricular
contraction
bicuspid valve
where can bicuspid valve found in the AV valve?
left
prevents backflow of
blood from right ventricle into
right atrium during ventricular
contraction
tricuspid valve
where can tricuspid valve found in the AV valve?
right
high pressure in
the atria causes both valves to OPEN and
blood from the atria flows to the
ventricles
atrial contraction,
both valves
CLOSE (since there is now low pressure in
the atria) and blood in ventricles could
not regurgitate to atria
ventricular contraction
tendonlike cords
where the cusps of the AV valves are
connected
chordae tendineae
the structures
where the chordae tendineae are
anchored
papillary muscles
carrying blood away
from the ventricles
Semilunar Valves
where can Semilunar Valves be found?
base of the large
blood vessels
each valve of the semilunar vavles consists of
3 crescent
moon-shaped cusps
prevents backflow of
blood from pulmonary trunk
into right ventricle during
ventricular relaxation
pulmonary valve
where can pulmonary valve be found
base of the
pulmonary trunk
what is the other name for pulmonary valve
pulmonic valve or
pulmonary semilunar valve
what is the other name for aortic valve
aortic semilunar
valve
where can aortic valve be found
base of the
aorta
prevents backflow of
blood from aorta into left
ventricle during ventricular
relaxation
aortic valve
during ventricular relaxation, ____ in the ventricles causes
both valves to CLOSE, preventing
blood to regurgitate from
pulmonary & systemic circulation
to the ventricles
low
pressure
during ventricular contraction,
___ in the ventricles
causes both valves to OPEN &
blood flows from ventricles to
the pulmonary & systemic
circulation
high pressure
“lub-dup” sound of
the heart w/c can be heard using a
stethoscope
HEART SOUNDS
why do sounds of the heart occured?
closure of the heart
valves
“lub” sound
S1 heart sound
due to the simultaneous closure of the
AV valves – tricuspid & bicuspid
S1 heart sound
“dup” sound
S2 heart sound
due to the simultaneous closure of the
semilunar valves – pulmonic & aortic
S2 heart sound
the network of blood vessels that
carry blood to & from the
myocardium
CORONARY CIRCULATION
carry oxygenated blood to the
myocardium
coronary arteries
compressed when the ventricles are
contracting & fill when the ventricles
are relaxed
coronary arteries
supply blood to the left atrium, most
of the left ventricle & part of the
right anterior ventricle
left coronary artery
has smaller branches that supply
blood to the right atrium, most of the
right ventricle & part of the left
posterior ventricle
right coronary artery
drain blood that has passed through
myocardial capillaries
carry CO2 & waste products from the
myocardium
coronary veins
an enlarged vein on the heart’s
posterior surface
coronary sinus
empties deoxygenated blood from
the coronary veins into the right
atrium
coronary sinus
the sequence of events in one
heartbeat
CARDIAC CYCLE
the heart’s natural pacemaker
Sinoatrial (SA) node
a specialized group of cardiac muscle
cells located in the wall of the right
atrium just below the opening of the
superior vena cava
Sinoatrial (SA) node
where the heart’s electrical activity
begins
Sinoatrial (SA) node
how many times in a minute initiates the action potentials of the SA node
60 to 80 times in a minute
it has the highest rate of
depolarization in the whole pathway, it
starts each heartbeat & sets the pace
for the whole heart
Sinoatrial (SA) node
located at the junction between atria &
ventricles (at lower interatrial septum)
Atrioventricular (AV) node
where impulses from the SA node
travel to
Atrioventricular (AV) node
transmission of impulses from the SA
node to the AV node and to the rest of
the atrial myocardium brings about
atrial depolarization, resulting in atrial
systole
also called “bundle of His”
Atrioventricular (AV) bundle
where impulses from the AV node
travel to
Atrioventricular (AV) bundle
where impulses from the bundle of His
travel to
Right & left bundle branches
transmits
impulses to right ventricle
right bundle branch
transmits
impulses to left ventricle
left bundle branch
where impulses from the left & right
bundle branches travel to
Purkinje fibers
spread the action potential within the
myocardium of the ventricle walls
ventricular depolarization,
resulting in ventricular systole
is a recording
of the electrical
changes in the
myocardium
during a
cardiac cycle
Electrocardiogram
the first wave
* reflects atrial depolarization
P wave
a series of waves which reflect
ventricular depolarization
QRS complex
since it is large, it obscures the
electrical activity of atrial
repolarization
QRS complex
the last wave
* reflects ventricular repolarization
T wave
refers to the volume of blood ejected
per minute from the left ventricle to
the aorta
CARDIAC OUTPUT
refers to the
degree of stretch
in the ventricle
before
contraction
Preload
the
more the cardiac
muscle fibers are
stretched, the more
forcefully they
contract
Frank Starling’s law
of the heart:
high force of
myocardial
contractility (e.g.
after administration
of Ca++ or
epinephrine) → high
stroke volume &
cardiac output
Force of contraction
high force of
myocardial
contractility (e.g.
after administration
of Ca++ or
epinephrine) → high
stroke volume &
cardiac output
Force of contraction
refers to the
amount of
resistance that
the ventricles
need to
overcome to
eject blood out
of the heart
Afterload
are sensory receptors
located in carotid sinus & aortic arch w/c sense changes in BP and send signals to the brain via CN IX & X.
baroreceptors
same location as
baroreceptors; sense changes in the O2
& CO2 content of blood & also send
signals to the brain via CN IX & X
chemoreceptors
heart rate of < 60 bpm
bradycardia
heart rate of > 100 bpm
tachycardia=
the amount of blood ejected by the left ventricle during each contraction (average: 60-80 mL)
stroke volume
the number of heartbeats per minute (average: 60-80 bpm)
heart rate
What is the formula of cardiac output
CO= HR X SV = 75 beats slash over min x 70 ml over beat slash = 5250 ml over min = 5.25 L over min
generates impulses to maintain
heart rate at 60-80 bp
Sinoatrial (SA) Node
may be influenced by other factors that speed up or slow down heart rate
Sinoatrial (SA) Node
area of the brain stem which contains 2 cardiac centers
medulla oblongata
What is the two cardiac centers in the medulla oblongata
accelerator & inhibitory centers
sends impulses along sympathetic nerves→norepinephrine & epinephrine
accelerator center
sends impulses along parasympathetic nerves, mainly the vagus nerve → acetylcholine
inhibitory center
increased levels of these hormones increase metabolism & thereby heart rate
T3 & T4
increases the heart rate
Caffeine & nicotine
