Angela Luna P.2 Cardiovascular System
Major components and functions of Blood
Components
plasma
55% whole blood
least dense component
buffy coat
leukocytes and platelets
<1% of whole blood
erythrocytes
45% of whole blood
most dense component
straw-colored sticky fluid; 90% water
small-diameter (7.5 μm) cells that contribute to gas transport
biconcave disc shape, is anucleate, no organelles
Functions
transport
delivers O2/ nutrients to body cells
transport metabolic waste to lungs/ kidneys for elimination
transport hormones from endocrine organs to target organs
regulation
maintaining body temp by absorbing/ distributing heat
maintaining normal pH using buffers; alkaline reserve of bicarbonate ions
maintaining adequate fluid volume in circulatory system
protection
prevent blood loss: plasma proteins & platelets in blood initiate clot formation
prevent infection: antibodies, complement proteins, white blood cells
ABO, Rh blood types
AB
blood that can be received: A, B, AB, O (universal recipient)
B
blood that can be received: B, O
A
blood that can be received: A, O
O
blood that can be received: O (universal donor)
Rh type is either positive or negative
Major functions of the cardiovascular system
circulates oxygen and removes carbon dioxide
Anatomy of Heart
right side receives oxygen-poor blood from tissues
pumps blood to lungs to get rid of CO2, pick up O2, via pulmonary circuit
left side receives oxygenated blood from lungs
pumps blood to body tissues via systemic circuit
Structural/ Functional Differences Between Blood Vessel Types
Layers of Heart
Disorders of Cardiovascular System
Major Blood Vessels
Cardiac Cycle & ECG
Vital Signs
Blood Flow Through Heart
base (posterior surface) leans toward right shoulder
apex points toward left hip
Coverings
pericardium: double-walled sac that surrounds heart; made up of two layers
parietal layer: lines internal surface of fibrous pericardium
visceral layer (epicardium): on external surface of heart
layers separated by fluid-filled pericardial cavity
Atria: the receiving chambers
small, thin-walled chambers; contribute little to propulsion of blood
right atrium: receives deoxygenated blood from body
superior vena cava: returns blood from body regions above the diaphragm
inferior vena cava: returns blood from body regions below the diaphragm
coronary sinus: returns blood from coronary veins
left atrium: receives oxygenated blood from lungs
Ventricles: the discharging chambers
right ventricle: most of anterior surface; pumps blood into pulmonary trunk
left ventricle: posteroinferior surface; pumps blood into aorta
trabeculae carneae: irregular ridges of muscle on ventricular walls
papillary muscles: project into ventricular cavity
actual pumps of heart
Valves
atrioventricular (AV ) valves: prevent backflow into atria when ventricles contract
tricuspid valve (right AV valve): made up of three cusps and lies between right atria and ventricle
mitral valve (left AV valve, bicuspid valve): made up of two cusps and lies between left atria and ventricle
chordae tendineae: anchor cusps of AV valves to papillary muscles
semilunar (SL) valves: prevent backflow from major arteries back into ventricles
pulmonary semilunar valve: located between right ventricle and pulmonary trunk
aortic semilunar valve: located between left ventricle and aorta
epicardium: visceral layer of serous pericardium
myocardium: circular or spiral bundles of contractile cardiac muscle cells
endocardium: innermost layer; is continuous with endothelial lining of blood vessels
Interatrial septum: separates atria
Interventricular septum: separates ventricles
Surface features
coronary sulcus (atrioventricular groove)
anterior interventricular sulcus
posterior interventricular sulcus
RIGHT SIDE
superior/ inferior vena cava
right atrium
tricuspid valve
right ventricle
pulmonary semilunar valve
pulmonary trunk
pulmonary artery
lungs
LEFT SIDE
pulmonary veins
left atrium
mitral (bicuspid) valve
left ventricle
aortic semilunar valve
aorta
systemic circulation
Arteries
carry blood away from heart
elastic arteries: thick-walled with large, low-resistance lumen
act as pressure reservoirs that expand and recoil as blood is ejected from heart
muscular arteries: deliver blood to body organs
arterioles: smallest of all arteries
control flow into capillary beds via vasodilation and vasoconstriction of smooth muscle
Capillaries
microscopic vessels; diameters so small only single RBC can pass through at a time
walls thin tunica intima; in smallest vessels, one cell forms entire circumference
functions: exchange of gases, nutrients, wastes, hormones, etc., between blood and interstitial fluid
capillary bed: interwoven network of capillaries between arterioles and venules
Veins
carry blood toward the heart
capillaries unite to form postcapillary venules
larger venules have one or two layers of smooth muscle cells
have all tunics, but thinner walls with large lumens compared with corresponding arteries
tunica media= thin, tunica externa= thick
venous valves: prevent backflow of blood; most abundant in veins of limbs
venous sinuses: flattened veins with extremely thin walls
Electrocardiogram (ECG/ EKG): a graphic recording of electrical activity
P wave: depolarization of SA node and atria
QRS complex: ventricular depolarization and atrial repolarization
T wave: ventricular repolarization
P-R interval: beginning of atrial excitation to beginning of ventricular excitation
S-T segment: entire ventricular myocardium depolarized
Q-T interval: beginning of ventricular depolarization through ventricular repolarization
Cardiac cycle: blood flow through heart during one complete heartbeat
Systole: period of heart contraction
Diastole: period of heart relaxation
atrial systole & diastole are followed by ventricular systole and diastole
cycle represents series of pressure and blood volume changes
mechanical events follow electrical events seen on ECG
pulmonary trunk: carries oxygen-poor blood from right ventricle into left/ right pulmonary arteries; carry blood to lungs
pulmonary vein: Carry oxygen-rich blood from your lungs to your heart; directly empty into left atrium
aorta: carries oxygen-rich blood directly out of your heart’s left ventricle; flows into branches to nourish the body
superior vena cava: delivers oxygen-poor blood from upper body into right atrium
inferior vena cava: delivers oxygen-poor blood from lower body into right atrium
provides cells with nutrients
removes the waste products of metabolism to the excretory organs for disposal
protects the body against disease and infection
clotting stops bleeding after injury
myocardial infarction (heart attack): blood flow to part of the heart is blocked; blood clot, high blood pressure
peripheral artery disease: arteries narrow & reduce blood flow to extremities
cerebrovascular accident (stroke): blood flow to a portion of the brain is interrupted; clogged arteries
endocarditis & myocarditis: inflammation of heart; heart valve damage
congenital heart disease: issue with heart structure and/or function present from birth
blood pressure: force per unit area exerted on wall of blood vessel by blood
-expressed in mm Hg
-measured as systemic arterial BP in large arteries near heart
SYSTOLIC PRESSURE: pressure exerted in aorta during ventricular contraction
DIASTOLIC PRESSURE: lowest level of aortic pressure when heart is at rest
pulse: throbbing of arteries due to difference in pulse pressures
Vital signs: pulse, blood pressure, respiratory rate, body temperature
radial pulse (taken at the wrist): most routinely used
pressure points: areas where arteries are close to body surface
-normally less than 120 mm Hg
-normally less than 80 mm Hg
-pressure when sounds first occur as blood starts to spurt through artery
-pressure when sounds disappear because artery no longer constricted
respiratory rate: normal respiration rates for an adult= 12 to 16 breaths per minute
body temp: normal body temperature can range from 97.8 degrees F to 99 degrees F