The Cardiovascular System
Transcript of The Cardiovascular System
THE CARDIOVASCULAR SYSTEM
EMERITA C. MENDOZA, R.N., M.D.
LOCATION OF THE HEART
• Hollow, muscular organ
• PMI is at the 5th left MCL
• Weighs 1 lb.
FUNCTIONS
• Transports O2 from the lungs to
tissues of the body• Delivers nutrients from the GIT to all systems• Carries wastes from tissues to the excretory
system• Serves as a route for hormones, enzymes,
and other chemicals to reach target tissues
LAYERS OF THE HEART
3 layers within a sac: • Endocardium
(Inner)
• Myocardium (Middle)
• Epicardium or visceral pericardium
(Outer)• surrounded by
parietal pericardium
• Myocardium is the thickest layer
• Unique because of the presence of INTERCALATED DISCS allows a single stimulation to cause all cardiac muscle fibers to contract.
MUSCLES WITHIN THE CHAMBERS
• PAPILLARY MUSCLES - found within the chamber walls
• Extend into CHORDAE TENDINAE attached to valves
BLOOD FLOW THROUGH THE HEART
• Left LUNGS LA mitral valve opens LV mitral valve closes LV muscles contract AV opens aorta distribution
• Right BODY RA tricuspid valve opens RV tricuspid valve closes RV muscles contract pulmonary valves open lungs
HEART SOUNDS
• Aortic valve: second ICS(intercostal space) R
PSL(parasternal line)
• Pulmonic valve: second ICS L PSL
• Tricuspid valve: fourth ICS L PSL
• Mitral valve: fifth ICS L MCL(midclavicular line)
HEART SOUNDS
• S1 : closure of mitral and tricuspid; “lub” sound
• S2: closure of aortic and pulmonic; “dub” sound
• S3: ventricular gallop
• S4: atrial gallop
CONDUCTION SYSTEM
• Sympathetic ( increase in CR,
norepinephrine or epinephrine is increased)
• Parasympathetic ( decrease in CR)• Creates an electrical impulse/activity
ELECTROCARDIOGRAM
• Measures the electrical activity of the heart
• 3 major limb leads: AVR, AVL, AVF (right & left wrists, left foot); V1 to V6 (precordial leads)
• Normal cycle: NSR(normal sinus rhythm)
• P wave (atrial contraction), QRS complex (ventricular contraction)
When the heart contractsWhen the heart relaxes
Cardiac Rate and Pulse Rate
• CR obtained via auscultation; PR is palpated.
• Most common pulses:
- Radial pulse - Carotid pulse - Femoral pulse - Dorsalis pedis
BLOOD PRESSURE
• Pressure when the heartbeat can be heard (Systolic = contraction pressure)
• Pressure when the heartbeat disappears (Diastolic = relaxation pressure)
• BP is expressed as systole/ diastole
•
JNC VII (Joint National Committee on the Prevention,
Detection, Evaluation & Treatment of High BP)
CATEGORY SYSTOLIC
DIASTOLIC
NORMAL <120 <80
PREHYPERTENSION
120-139
80-89
STAGE I 140-159
90-99
STAGE II >/= 160 >/= 100
STARLING’S LAW OF THE HEART
• All venous return is accommodated by contractility of the cardiac muscle fibers.
• May be called EJECTION FRACTION (EF) percentage of blood pumped into the aorta from the left ventricle
• Cardiac output= stroke volume x cardiac rate
PULSE RATE
• Place the tips of digits 2 and 3 (index and middle fingers) over the surface where the artery is found
• Feel the pulse and count per minute
• Normal adult PR: 60-100 bpm (beats per minute)
• < 60 = Bradycardia• > 100 = Tachycardia
THE VASCULAR CIRCULATIONS
• Blood flow through the body is the Systemic circulation
• Blood flow through the lungs is the Pulmonary circulation
• The Hepatoportal circuit is a subdivision of the systemic that serves the liver
• The Circle of Willis is the systemic circuit at the base of the brain
• FetalFetal circulation differs from an adult circulation differs from an adult
General Plan of the
Systemic & Pulmonary
Circulations