HEART

STRUCTURE of HEART
• Blunt cone shape about clenched fist of the owner
but not exactly
• 12 cm long, 9 cm wide (5” x 3.5”)
• Weight
o Adult male: 250g to 390g (310 g)
o Adult female: 200g to 275g (225g)
o Accounts about 5% of the bodyweight
• the workhorse of the cardiovascular system • Location: center of thorax, inside the mediastinum
o as it pumps blood for 24 hrs to supply (does not include the lungs; space between the
the different tissues and remove waste lungs b/n the pleural sac of the lungs)
products • Slanted diagonally to the left side
• Propels blood through the 50, 000 miles of blood o 2/3rds of its bulk to left side of the body
vessels in the body midline
• Beats approximately 100,000 times each day • TERM
• 7, 000 to 7,400 L/day :pumps blood o Apex—pointed end of the heart
• 2.5 billion times an average lifetime : contraction o Base—upper most part

NORMAL RESTING HEART RATE AVERAGE

Neonate 120-160 CPM 140 CPM
1 y/o 80-160 CPM 120 CPM • PERICARDIUM—a membrane; a protective sac
3 y/o 80-120 CPM 110 CPM that surrounds the pericardial cavity which contain
6 y/o 70-115 CPM 100 CPM small amount of pericardial fluid, which encloses the
10 y/o 70-110 CPM 90 CPM heart
14 y/o 60-110 CPM 85-90 CPM
Adult 60-100 CPM 72 CPM
o CPM—cycle per minute

DIFFERNTIATE CARDIOVASCULAR & CIRCULATORY SYSTEM

Cardiovascular System Circulatory System LAYERS of THE HEART
-
1. Epicardium—the visceral pericardium
• Outer protective layer of the heart
• Inner layer of the fibrous sac pericardium
• The serous membrane that surrounds the
myocardium
2. Myocardium (heart muscle)
• Consist of thick bundles of cardiac muscles
twisted in hoarded into ring-like
arrangement CHAMBERS of THE HEART
• The layer of the heart that actually
contracts • INTERVENTRICULAR SEPTUM—divides the heart
• Reinforced internally by the dense, fibrous vertically into right and left
connective tissue network—“skeleton of the • Auricle—an ear shaped muscular part that sticks
heart” (but is not explained to as a bone) out from the surface of each upper chamber
atrium of the heart
• Makes up the 4 chambers of the heart
1. Atrium—upper chambers of the heart that
3. Endocardium—3rd layer, innermost
receives blood from the veins and pumps it to the
• A thin, glistening sheath o0f endothelium that ventricles
lines the heart chambers • Receive deoxygenated blood from superior
• Continuous with the lining of the blood vessel and inferior vena cava
2. Ventricles—lower chambers that receives blood
from the atria and contract to force blood out of
the ventricles into arteries
• Receive blood from lungs
 ---Right and left coronary arteries—is the main that
VALVES of THE HEART supply oxygen; the 1st and 2nd branches of aorta, and
to be collected by cardiac veins (coronary veins)
• Prevent the backflow of blood
• Allow blood to flow through the heart in one direction
1. Atrioventricular valve—the 2 valves that allow
blood to flow from atria to the ventricles BLOOD VESSELS OF THE HEART
• Upper and lower chambers 1. Pulmonary arteries—carry deoxygenated/
a) Tricuspid valve—right atrioventricular valve oxygen-poor blood
• Consists of 3 flaps that prevent 2. Pulmonary vein—carry oxygenated blood/
blood from flowing back into the right oxygen-rich blood from lungs to heart
atrium when the right ventricles 3. Superior vena cava and Inferior vena cava—
contract to pulmonary artery drains venous blood from upper and lower parts
• DEOXYGENATED BLOOD of the body to the heart
b) Bicuspid valve (mitral valve)—left 4. Aorta—carry highly oxygenated blood from
atrioventricular valve heart to body cells and tissues
• The on-way valve between the a. Ascending—upward aorta from left
atrium (upper chamber) and ventricle
ventricle (lower chamber), on the b. Arch of aorta—where it bends
left side of the heart c. Descending (downward)—from arch of aorta
• OXYGENATED BLOOD to extend to lower part of the body
• Abdominal aorta

2. Semilunar valve—prevent blood in the pulmonary

trunk and aorta from flowing back into the
ventricles→ one-way flow
• Right and Left chambers
a) Pulmonary semilunar valve—oxygen-poor
blood to enter the pulmonary trunk on its
way to the lungs from the right ventricle
b) Aortic semilunar valve—oxygenated blood to
enter the aorta from the left ventricle
• Allow freshly oxygenated blood to enter
aorta from left ventricle
----Left semilunar valve is highly stronger than right
semilunar valve
 • Imposes a single rhythm on all the atrial
muscle cells
• Conductor of orchestra that leads the
FUNCTIONS OF THE HEART contraction of other nodes/ mechanisms
1) Receive oxygen-poor blood from the body and • Depolarizes at the rate of 70 to 80
sends it to the lungs for a fresh supply of times per minute (75 per min)
oxygen o When the atria depolarizes, it
2) Pumps newly oxygenated blood to different body will then contract
parts for the cell’s aerobic respiration o Contraction of atria, ventricles
relax
2) Atrioventricular node—delays the impulse from
atria (to contract) while the ventricles fill
• 40 to 60 per minute
PROPERTIES OF CARDIAC MUSCLE • In the lower interatrial septum
CELLS
• By 0.095 seconds or 0.09 seconds in the
1. Cardiac muscle cells function as a coordinated delay to ensure that atria have ejected
unit (sabay) to physiological stimulation rather blood to ventricle
than as a group 3) Bundle of his or Atrioventricular bundle—arises
2. Cardiac muscle contains a large number of to the AV node and conducts impulse to
mitochondria the bundle branch system
o Which is the powerhouse of the cell that a) Right bundle branch: anterior lateral, and
provides a constant source of ATP posterior; transmits impulses down the right
(adenosine triphosphate), (a chemical energy side of the interventricular septum
for muscular activities) for the hardworking b) Left bundle branch: divided into anterior and
heart muscle posterior
3. Abundant blood and a high concentration of • Anterior portion—transmits the
myoglobin (a muscle cell that stores oxygen) impulses to the anterior-endocardial
surface of the left ventricle
• Posterior portion—transmits the
CONDUCTION SYSTEM—transmission of impulses over the posterior and inferior-
electrical impulses for contraction to enable pumping endocardial surfaces
---Two types of cells--- 4) Purkinje fibers—transmits the impulses to the
ventricles and provide for depolarization, then
1) Myocardial/ muscle cell—responsible for the next is CONTRACTION to the ventricle
heart’s pumping action • 30 per minute
2) Electrical cells—responsible for generating and • For the ventricles to contract
conducting electrical current (that stimulates
muscle cell to contract) for heart contraction

CONDUCTION SYSTEM OF THE HEART

• At different rate under different condition;
shows heart beat when at rest
1) Sino atrial (SA) node—internal pacemaker
located in the walls of right atrium that sends a
rhythmic electrical impulses to regulate heart
beat
• Composed of clump (small mass) of
specialized cardiac muscle
• “Bachmann’s bundle” of the heart, which
leads to the Left atrium in SA node
 o Results to action reaction/
create nerve
impule________for the cell to
contract
o Positive wave of heart cell
o Point polarity inside, more Na ion
2. Repolarization—the restoration of the
normal electrical polarity of a nerve or
muscle after muscle contraction

• Electrocardiograph
ATTACHING ELECTRODES—to the skin and
recording activity can visualize electrical activity of the 1) P wave—atrial depolarization
heart by electrocardiograph • transmission of electrical impulses from
the SA node throughout the atrial
myocardium
2) QRS--Ventricular Depolarization
• electrical impulses spread throughout
the ventricular myocardium
3) T wave--ventricular Repolarization
• activity occurring as ventricle relax
IMPORTANCE of ECG Result
• fort the diagnosis of the client

CARDIAC OUTPUT
• Electrocardiogram • The total amount of blood pump by the
o A visual record of the heart’s electrical activity ventricles each minute
made, using an electrocardiograph machine
(ECG/ EKG machine) --→ECG of the client
o POLARIZATION—the substances of opposite 2 Factors
charges are separated in the cell
1) Heart Rate -number of contractions the heart
▪ Polarized when at rest (heart cell) undergoes per minute
▪ Ion concentration are different inside and
• Ex: 60-80 bpm Cardiac output= stroke
outside the cell volume
1. Depolarization—the loss of electrical
• Cardiac output=stroke volume
charge on the surface of the cell
2) Stroke Volume -amount of blood pumped by
membrane
each ventricle during contraction
o Very rapid
o Contraction of myocardium
CARDIAC CYCLE HEART SOUNDS
1) Systole - Contraction of the atria and ventricle • First and second sound
during which blood id pumped to the arteries
• Lubb and Dupp
• Higher pressure than diastole o Lubb
• Contraction ▪ When blood is push out from the heart
2) Diastole into the body
• rhythmic expansion of the chambers ▪ - Occurs during ventricular contraction
of the heart at each heart beat ▪ when the atrioventricular valves are
• relaxation closing
o Dubb
▪ When blood is push out from the heart
4 Stages into the body
▪ - Occurs during ventricular contraction -
1) Atrial Systole - Both atria contract, forcing blood when the atrioventricular valves are
into the ventricles closing
2) Ventricular Systole (.3 sec) - Both ventricles
contract forcing the blood out through the
pulmonary artery to the lungs and aorta to • The recording of the heart sound is called
rest of the body PHONOCARDIOGRAM which shows heart sound as
waves
• EDV - End diastolic volume
o - Amount of blood in the
ventricles right before
ventricular contraction
3) Atrial Diastole (.7 sec) - Relaxation of the atria NORMAL RANGE of BLOOD PRESSURE in the BODY
• Ventricles remain contracted and the
atria begins to fill with blood from the SYSTOLIC DIASTOLIC AVERAGE
large veins leading to the heart from - New 65-90 30-60 80/46
the body born mm/Hg
4) Ventricular Diastole (.5 sec) - Relaxation of the Infant 65-115 42-80 80/46
ventricle before the atrial systole allowing mm/Hg
3 y/o 76-112 42-84 99/65
ventricles fill with blood from atria mm/Hg
• ESV - End systolic volume 6y/o 85-115 46-84 100/56
o Amount of blood left at the mm/Hg
ventricle right after ventricular 10 y/o 93-125 48-64 100/56
contraction mm/Hg
14 y/o 99-137 46-68 118/61
mm/Hg
adult 100-140 51-71 120/80
mm/Hg
elderly 100-160 60-90 130/80
mm/Hg

• 140—hypertension
• 130—prehypertension
Oxygenated Blood Lungs→ pulmonary veins→ atrium→
mitral valve→ left ventricle→ aortic valve→ aorta→
body (cells/tissue)

Oxygenated Blood Lungs→ pulmonary veins→ atrium→

mitral valve→ left ventricle→ aortic valve→ aorta→
body (cells/tissue)

deoxygenated blood

superior and inferior vena cava

right atrium

right ventricle

mitral/ bicuspid valve

pulmonary valve

pulmonary trunk

pulmonary artery

LUNGS

pulmonary vein

left atrium

tricuspid valve

left ventricle

aortic valve

aorta

TO THE REST OF THE BODY