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heart
a muscular organ that is essential for life because it pumps blood through the body.
a member organ of the cardiovascular system
two pumps in one
five liters
The heart of a healthy adult, at rest, pumps approximately how many liters of blood per minute?
75 years
the heart continues to pump at approximately that rate for more than, how many years?
pulmonary
heart’s right side pumping to the lungs and back to the left side of the heart through vessels of what circulation?
systemic
the left side of the heart pumps blood to all other tissues of the body and back to the right side of the heart through vessels of what circulation?
Generates blood pressure
Routes blood
Ensures one-way blood flow
Regulates blood supply
functions of the heart
size of a fist and weighs less than 1 pound (lb).
what is the size of the heart?
between lungs in thoracic cavity
where is the heart located?
apex (bottom) towards left side
what is the orientation of the heart?
pericardium
pericardial sac
double-layered sac that anchors and protects the heart
surrounds the heart and anchors it within the mediastinum
parietal pericardium
membrane around heart cavity
visceral pericardium
membrane on heart’s surface
pericardial cavity
space around the heart
coronary sulcus
extends around the heart, separating the atria from the ventricles.
sulci
two grooves
which indicate the division between the right and left ventricles, extend inferiorly from the coronary sulcus.
anterior interventricular sulcus
extends inferiorly from the coronary sulcus on the anterior surface of the heart
posterior interventricular sulcus
extends inferiorly from the coronary sulcus on the posterior surface of the heart
superior vena cava
inferior vena cava
they carry blood from the body to the right atrium
drain blood from most of the body
four pulmonary veins
carry blood from the lungs to the left atrium
two arteries
great vessels or great arteries
carry blood away from the ventricles of the heart.
pulmonary trunk
arising from the right ventricle
splits into the right and left pulmonary arteries, which carry blood to the lungs.
aorta
arising from the left ventricle
carries blood to the rest of the body.
left atrium (LA)
right atrium (RA)
left ventricle (LV)
right ventricle (RV)
chambers of the heart
atria
superior chambers
holding chambers
small, thin-walled
contract minimally to push blood into ventricles
primer for pumps
blood first enters here
interatrial septum
it separates the right and left atria
ventricles
inferior chamber
pumping chamber
thick, strong-walled
contract forcefully to propel blood out of the heart
actual pump
interventricular septum
separates the right and left ventricles
atrioventricular heart valves
these are valves between the artia and ventricles
tricuspid valve
an atrioventricular valve between right atrium and right ventricle
has 3 cusps
bicuspid valve
mitral valve
an atrioventricular valve between left atrium and left ventricle
has 2 cusps
papillary muscles
each ventricle contains cone-shaped, muscular pillars called, what?
chordae tendineae
papillary muscles are attatched by strong, connective tissue strings called (BLANK), to free margins of the cusps of the atrioventricular valves
by pulling on the chordae tendineae attached to the valve cusps.
when the ventricles contract, the papillary muscles contract and prevent the valves from opening into the atria, by how?
semilunar heart valves
have three half-moon shaped cusps
are valves between the pulmonary trunk and aorta
pulmonary semilunar valve
a valve between right ventricle and pulmonary trunk
aortic semilunar valve
a valve between left ventricle and aorta
cardiac skeleton
fibrous skeleton
a plate of connective tissue, consists mainly of fibrous rings that surround the atrioventricular and semilunar valves and give them solid support.
serves as electrical insulation between the atria and the ventricles and provides a rigid attachment site for cardiac muscle.
1. RA
2. Tricuspid valve
3. RV
4. Pulmonary semilunar valve
5. Pulmonary trunk
6. Pulmonary arteries
7. Lungs
8. Pulmonary veins
9. LA
10. Bicuspid valve
11. LV
12. Aortic semilunar valve
13. Aorta
14. Body
blood flow through heart
coronary arteries
supply blood to heart wall
originate from base of aorta (above aortic semilunar valve)
left coronary artery
has three branches
supply blood to anterior heart wall and left ventricle
right coronary artery
originates on right side of aorta
supply blood to right ventricle
cardiac veins
drain blood from the cardiac muscle
parallel to the coronary arteries
most drain blood into the coronary sinus
from the coronary sinus into the right atrium
epicardium
surface of the heart (outside)
myocardium
thick, middle layer composed of cardiac muscle
endocardium
smootth, inner surface of the heart wall
cardiac muscle
one centrally located nucleus
branching cells
rich in mitochondria
striated (actin and myosin)
Ca2+ and ATP —> used for contractions
intercalated disk connect cells
pacemaker potential
cardiac muscle action potentials
changes in membrane channels’ permeability are responsible for producing action potentials
depolarization phase
plateau phase
repolarization phase
cardiac muscle action potential: phases
depolarization phase
Na+ channels open
Ca2+ channels open
plateau phase
Na+ channels close
some K+ channels open
Ca+ channels remain open
this phase prolongs action potential by keeping Ca2+ channels open.
repolarization phase
K+ channels are open
Ca+ channels are close
200-500
cardiac muscles takes about, how many msecs?
conduction
contraction of the atria and ventricles is coordinated by specialized cardiac muscle cells in the heart wall that form, what system of the heart?
sinoartial node
atrioventricular node
atrioventricular bundle
R&L bundle branches
purkinje fibers
conduction system of the heart
sinoartial (SA) node
in right atria
where action potential originates
functions as pacemaker
large number of Ca+ channels
atrioventricular (AV) node
located in the lower portion of the right atrium
action potentials from SA node sent to this node
action potentials spread slowly through it
slow rate of action potential conduction allows the atria to complete their contraction before action potentials are delivered to the ventricles
atrioventricular bundle
action potentials from AV node travels here
it divides into a left and right bundle branches
purkinje fibers
at the tips of the left and right bundle branches
pass to the apex of the heart and then extend to the cardiac muscle of the ventricle walls
action potentials are rapidly delivered to all the cardiac muscle of the ventricles
SA node
AV node (atrioventricular)
AV bundle
Right and Left Bundle branches
Purkinje fibers
action potential path through the heart
electrocardiogram
ECG, EKG
record of electrical events in the heart
diagnoses cardiac abnormalities
uses electrodes
components of ECG/EKG: P wave, QRS complex, T wave
P wave
component of ECG/EKG
depolarization of atria
QRS complex
component of ECG/EKG
depolarization of ventricles
contains Q, R, S waves
T wave
component of ECG/EKG
repolarization of ventricles
cardiac cycle
summative description of all the events that occur during one single heartbeat.
pressure changes
what are responsible for blood movement?
from areas of high to low pressure.
how does the blood move?
cardiac muscle contractions
these contractions produce pressure changes within heart chambers.
atrial systole
ventricular systole
atrial diastole
ventricular diastole
cardiac cycle
atrical systole
cardiac cycle; contraction of the atria
ventricular systole
cardiac cycle; contraction of the ventricles
artial diastole
cardiac cycle; relaxation of the atria
ventricular diastole
cardiac cycle; relaxation of the ventricles
due to the closure of heart valves.
how are heart sounds produced?
stethoscope
what is used to hear heart sounds?
lubb
what does the first heart sound make?
dupp
what does the second heart sound make?
the closure of the atrioventricular valves.
the first heart sound is due to, what?
the closure of the semilunar valves.
the second heart sound is due to, what?
stroke volume
volume of blood pumped per ventricle per contruction
70 milliliters/beat
heart rate
number of beats in one minute
72beats/min
cardiac output
volume of blood pumped by a ventricle in one minute
5 liters/min.
CO= SV x HR
cardiac output formula:
intrinsic regulation
refers to the mechanisms contained within the heart itself that control cardiac output.
venous return
the amount of blood that returns to heart
preload
the degree ventricular walls are stretched at end of diastole
Starlings Law of the Heart
relationship between preload and stroke volume
influences cardiac output
e.g., exercise increase venous return, preload, stroke volume, and cardiac output.
after load
pressure against which ventricles must pump blood
extrinsic regulation
refers to mechanisms external to the heart, such as either nervous or chemical regulation.
sympathetic and parasympathetic nerve fibers
what innervates the sinoatrial (SA) node?
baroreceptor reflex
a mechanism of the nervous system that plays an important role in regulating heart function.
baroreceptors
monitor blood pressure in the aorta and carotid arteries
changes in blood pressure cause changes in frequency of action potentials
involves the medulla oblongata
chemoreceptor reflex
involves chemical regulation of the heart
epinephrine
norepinephrine
neurotransmitters and hormones from the adrenal medulla that increases heart rate and stroke volume
excitement, anxiety, and anger
these emotions can increase cardiac output
depression
mental disorder; can decrease cardiac output
pH and CO2
medulla oblongata has chemoreceptors for changes in, what?
coronary artery disease
heart disease; due to decrease blood supply to the heart
coronary arteries are narrowed for some reason
myocardial infarction
heart attack
due to closure of one or more coronary arteries
area(s) of cardiac muscle lacking adequate blood supply die, and scars (infarct)
angioplasty
procedure; opens blocked blood vessels
stent
structures inserted to keep vessels open
Note
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