Xiomara Sanchez, period 3, Cardivascular System
Major components and functions of Blood
Component
Red blood cell
(erythrocyte)
function; Transports oxygen and carbon
dioxide
White blood
cell (leukocyte)
function; Destroys pathogenic microorganisms and parasites and removes worn cells
Neutrophil
Phagocytizes small particles
Eosinophil
Kills parasites and moderates
allergic reactions
Basophil
Releases heparin and
histamine
Monocyte
Phagocytizes large
particles
Lymphocyte
Provides immunity
Platelet (thrombocyte)
Helps control loss from
broken vessels
ABO, Rh blood types
ABO
Blood groups are based on presence or absence of 2 important
antigens on RBC membranes: antigen A and antigen B
Type A blood has A antigens on RBC membranes and anti-B
antibodies in the plasma
Type B blood has B antigens on RBC membranes and anti-A
antibodies in the plasma
Type AB blood has both A and B antigens on RBC membranes, but neither type of antibodies in the plasma; universal recipient
Type O blood has neither antigen on RBC membranes, but both
types of antibodies in the plasma; universal donor
Antibodies of one type will react with antigens of the same type,
and cause agglutination
RH
In humans, group includes several Rh antigens or factors
Most common antigen of the group is Antigen D
If the Rh factor (antigen D) is present on a person’s red blood cells, the blood is Rh positive; if absent, the blood is Rh negative
There are 2 ways in which an Rh-negative individual can have
contact with Rh-positive blood: a transfusion or pregnancy
If an Rh-negative woman carries an Rh-positive baby, she may be exposed to the Rh-positive blood during delivery
Major functions of the cardiovascular system
Cardiovascular system: a closed circuit that consists of the heartand blood vessels (arteries, capillaries, and veins)
A functional cardiovascular system is vital for supplying oxygen and nutrients to tissues and removing wastes from them
Arteries transport blood away from the heart, veins transport
blood toward the heart, and capillaries are vessels that run between arteries and veins
Oxygen-poor blood is carried by the pulmonary circuit to the
lungs, where it picks up oxygen and drops off carbon dioxide
The systemic circuit sends oxygen-rich blood to all body cells, where it drops of oxygen and picks up carbon dioxide
Anatomy of the heart (including all chambers, and valves)
Heart valves
Tricuspid valve; Prevents blood from moving from the
right ventricle into the right atrium during ventricular contraction
Pulmonary valve; Prevents blood from moving from the
pulmonary trunk into the right ventricle during ventricular relaxation
Mitral (bicuspid) valve; Prevents blood from moving from the
left ventricle into the left atrium during ventricular contraction
Aortic valve; Prevents blood from moving from the
aorta into the left ventricle during ventricular relaxation
Chambers
Right atrium; receives blood low in oxygen from the body and then empties the blood into the right ventricle.
Left atrium; receives blood full of oxygen from the lungs and then empties the blood into the left ventricle
Right ventricle; umps blood low in oxygen to the lungs
Left ventricle; pumps blood full of oxygen out to the body.
Layers of the heart
Epicardium
a serous membrane that forms the innermost layer of the pericardium and the outer surface of the heart.
Myocardium
the muscular tissue of the heart.
Endocardium
The endocardium is the innermost layer of the heart. It lines the inner surfaces of the heart chambers, including the heart valves. The endocardium has two layers. The inner layer lines the heart chambers and is made of endothelial cells.
Blood flow through the heart and body
Blood flow proceeds in a continuous circle
Two circuits, or subdivisions, for blood flow with respect to gas exchange:
Pulmonary circuit: Blood flow between heart and lungs
Systemic circuit: Blood flow between heart and body tissues
Oxygen-poor blood returns to the right atrium via the superior and inferior venae cava and coronary sinus
The right atrium contracts, forcing blood through the tricuspid valve into the right ventricle
The right ventricle contracts, closing the tricuspid valve, and forcing blood through the pulmonary semilunar valve into the pulmonary trunk and arteries
The pulmonary arteries carry blood to the lungs, where it enters alveolar capillaries, the site of gas exchange with the alveoli of the lungs; here the blood drops off carbon dioxide and picks up oxygen
Oxygen-rich blood flows back to the left atrium of the heart via pulmonary veins
The left atrium pumps blood through the mitral (bicuspid) valve into the left ventricle
The left ventricle contracts, closing the mitral valve, opening the aortic semilunar valve, and pumping blood into the aorta for distribution to the systemic circuit of the body
Structural and functional differences between blood vessel types (arteries, veins, capillaries)
Cardiac cycle and the ECG
Cardiac cycle
First the atria contract (called atrial systole), while ventricles
relax (called ventricular diastole)
Then the ventricles contract (called ventricular systole), while
the atria relax (called atrial diastole)
Then the entire heart relaxes for a brief moment
ECG
a recording of the electrical changes that occur
during a cardiac cycle
Recording results from the summed action potentials of many cardiac muscle cells which can be detected through electrical currents in the body fluids
Components of the ECG
P Wave: The first wave, which corresponds to the depolarization of the atria; this leads to the contraction of the atria
QRS Complex: Corresponds to the depolarization of ventricles, which leads to contraction of the ventricles; the repolarization of the atria occurs during the QRS complex but is hidden behind the larger ventricular event
T Wave: Corresponds to ventricular repolarization, and leads to
ventricular relaxation
Arteries
strong, elastic vessels adapted for carrying high-pressure blood
Arteries usually transport blood away from the heart
Arteries become smaller as they divide and give rise to arterioles
Capillaries
blood vessels with the smallest diameter
They connect small arterioles to small
They consist only of a layer of endothelium, through which
substances are exchanged with tissue cells (diffusion)
Veins
Thinner wall than an artery but with similar layers
the vein middle layer is much thinner; some veins have flaplike valves
Transports blood under relatively low pressure from a venule to the heart;
valves prevent backflow of blood; serves as a blood reservoir
Vital signs (BP and Pulse)
Blood Pressure
Force blood exerts against the inner walls of blood vessels
BP exists all through the cardiovascular system
The term "blood pressure" usually refers to systemic arterial
pressure
Pulse
The alternating expansion and recoil of the wall of an artery as
the ventricles contract and relax can be felt at certain points in
the body as a pulse
Common pulse points include the radial artery, carotid artery,
brachial artery, and femoral artery
The pulse rhythm, rate, force, and equality are assessed when palpating pulses.
Disorders of the cardiovascular system
Myocardial Infarction
blood flow to part of the heart is blocked (heart attack)
Risks: blood clot, obesity, & stress
symptoms: chest pain, sweating, & dizziness
Peripheral Artery Disease
Arteries narrow & reduce blood flow to extremities
Risks; limb trauma, smoking, & diabetes
Symptoms: leg & arm pain, weak pulse, wounds won´t heal
Cerebrovascular Accident (Stroke)
Blood flow to a portion of the brain is interrupted (stroke)
Risks: clogged arteries, Aneurysm, &age/race
Symptoms: Muscle weakness, memory loss, severe headache
Endocarditis & Myocarditis
Inflamation of the heart
Risks: recent surgery, heart valve damage, rheumatoid arthritis
Symptoms: chest pain, fatigue, & fever
Congenital Heart Disease
Issue with heart structure &/ or function present from birth
Symptoms: May cause death, dependent on condition, cyanosis common
Risks: Aortic stenosis, pulmonary stenosis, & VSD (ventrical septal defect