Transcript The Cardiovascular System

The Cardiovascular System
Heart-------Blood Vessels------Blood Cells
Medical Terminology
Anatomy of the Heart
•
4 chambers
– 2 upper = right & left atria separated by interatrial septum
– 2 lower = right & left ventricles separated by interventricular septum
– lining = 3 layers
1. Pericardium --- 2 layers:
a. parietal pericardium = pericardium
b. visceral pericardium = epicardium
peri = surrounding;
epi = upon;
endo = inner
2. Myocardium
3. Endocardium
•
Heart Valves
– Tricuspid = between right atrium & ventricle
– Bicuspid (Mitral) = between left atrium & ventricle
– Pulmonary semilunar = between R. ventricle & Pulmonary artery
– Aortic semilunar = between L. ventricle & aorta
• Blood Flow Through the Heart
– combines 2 circulatory systems
• Pulmonary circulation
– primarily right side of heart
– key = getting blood to lungs
• Systemic circulation
– primarily left side of heart
– key = getting blood to all
other parts of body
• Coronary Circulation
• 2 coronary arteries ---right coronary &
left coronary
» first two
branches off
ascending aorta
• supplies oxygen &
nutrients for heart,
especially
myocardium
• Conduction System of the Heart
– Impulse route through the heart
• SA node (sinoatrial) = “pacemaker”
» located in upper right corner of R. atrium near opening of
superior vena cava
» stimulates depolarization of both atria
• AV node (atrioventricular)
» located in inferior wall of R. atrium near a-v septum
» stimulates the initiation of depolarization of both ventricles
» slowing of impulses through this node allows time for the
ventricles to fill with blood from the contracting atria
• Bundle of His
» located at top of interventricular septum
• Right Bundle Branch
• Purkinje’s Fibers
&
Left Bundle Branch
Electrocardiogram
• The electrical impulses traveling through the heart are picked up at the
patient’s skin surface by a machine (electrocardiograph)
• 5 basic parts
1. P wave = atrial depolarization & contraction
2. P-R interval = time it takes from beginning of atrial contraction
to beginning of ventricular contraction
3. QRS wave = ventricular depolarization & contraction
4. S-T segment = time it takes from end of ventricular contraction
to the beginning of ventricular recovery
5. T wave = repolarization of the ventricles
Blood Vessels
vascular system --- vas = vessel (Latin)
• Structure
– Both arteries & veins have 3 layers of tissue
» Phleb/o- = combining form means vein
• outer layer = tunica externa (adventitia)
» composed of connective tissue
• middle layer = tunica media
» composed of muscle & elastic tissue
• inner layer = tunica intima
» composed of endothelium
» Veins have one-way flow valves from the endothelium
– Capillaries: only one (1) layer of endothelial cells
– Arterioles = small arteries
– Venules = small veins
• Vessels
– Arteries carry
blood away
from heart
– Capillaries join
arteries and vein
• Microscopic
• Nutrients and
oxygen
exchanged at
cellular level
– Veins carry blood
to the heart
• Functions of Blood Vessels
• Arteries
– distribution of nutrients
– maintenance of blood pressure
• Veins
– takes waste products back to heart for
circulation & disposal
– valves keep flow going in one direction
• Capillaries
– where internal respiration occurs
» i.e. the exchange of O2 & CO2
between vessel & cell
– where exchanges occur for nutrients,
wastes, and fluids
Blood Composition
• Blood = Plasma (55%) + Formed Elements (45%)
– Plasma = the liquid faction of blood; blood minus its formed element
– Serum = plasma minus clotting factors
– Formed Elements ---------- “The Cells”
• Red Blood Cells------------erythrocytes------------- 5 million/mm3
• White Blood Cells ------------leukocytes---------------5000/mm3
• Platelets --------------------
thrombocytes------------250,000/mm3
• Types of WBC’s
– granular:
» neutrophils (60%) ---------- phagocytes; first line of defense
» eosinophils (3%) ------------seen in allergies & parasitic diseases
» basophils (1%) -------------- release heparin & histamine
– nongranular:
» lymphocytes (30%)
* B lymphocytes
* T lymphocytes
» monocytes (5%) ---------------------- become macrophages
Blood Diseases
• Essentially one gets Too Much
or
Too Little
• RBC ---------------- polycythemia ---------------- anemia
• Platelets ---------- thrombocytosis ------------ thrombocytopenia
• WBC---------------- leukocytosis ------------------leukopenia
(-penia = poverty)
• Cancer of WBC’s = Too Much = leukemia
Cardiovascular Pathology
• Coronary artery disease
– Ischemia
(partial O2 block)
• Angina pectoris
– Infarct
(complete O2 block)
• Myocardial infarction
• Congestive heart failure
• Carditis
– Pericarditis
– Myocarditis
– Endocarditis
• Heart murmur
• Cardiac arrhythmia
– Tachycardia (2X)
– Flutter (3X)
– Fibrillation (4X)
• Aneurysm
• Raynaud’s phenomenon
• Thrombosis
• Phlebitis
• Varicose veins
• Thrombophlebitis
• Embolus
• Hypertension
– Essential hypertension
• Essential = idiopathic
– Secondary hypertension
– Malignant hypertension
Cardiovascular Procedures & Treatments
• Cardiac catheterization
• Stress test
– Thallium stress test
• Echocardiography
• Angioplasty
• Endarterecomy
(endo-; arter/o; -ectomy)
•
•
•
•
CABG
Valvuloplasty
Pacemaker
Defibrillation
Arteriolar disease
• Arteriosclerosis
• Atherosclerosis
• Thrombosis
• Embolus
• CVA = stroke =
cerebrovascular
accident