Cardiovascular Disease Chapter 42

Epidemiology  #1 killer in 2005 – 864,480 deaths due to CVD  CVD – CardioVascular Disease  Includes:  CHD (CAD) – Coronary Artery Disease (652,000)  Cerebrovascular Disease – Stroke (144,000)  Congestive Heart Failure

Arterial Disease = #1 killer  What do arteries do? -- Carry blood away from heart (oxygenated blood)  Why is oxygenated blood important? -- Oxygen allows respiration to take place

Arterial Disease = #1 killer Page 2  What do coronary arteries do? -- Supply cardiac muscle with oxygenated blood  How does coronary arterial disease = organism death? -- IF the heart cannot do respiration, muscle stops. -- IF cardiac muscle stops, then no oxygenated blood for the rest of the body

The Heart gets its oxygenated blood supply from the coronary arteries

Vascular Anatomy

Explain how Cerebrovascular Disease (Stroke) would develop?

Closed Circulatory System  Blood is contained within vessels and pumped around the body  Annelids, cephalopods, and all vertebrates  Arteries – Blood AWAY from the heart  Contain significant amount of smooth muscle  Arterioles – smaller branches of arteries  Capillaries – microscopic vessels  1 cell thickness  Veins – carry blood back TO the heart  Valves prevent backflow

Closed Circulatory System

Notes on Circulatory Cycle  Capillaries are for gas exchange  Arteries  Capillaries  Veins  Cardiac Cycle  Always Atrium  Ventricle  Atria – receive blood from body or lungs  Ventricles – receive blood from atria, pump to body or lungs  Right Atrium  right ventricle  lungs  Lungs  Left Atrium  Left Ventricle  Body  From Body  Veins  Right Atrium

Cardiac Anatomy 

Cardiac Cycle  Consists of a systole and diastole  Systole – contraction phase  Diastole – Relaxation phase  Heart Rate – rate of contractions per minute  Stroke volume – amount of blood pumped by the left ventricle during the systole

Cardiac Valves  Atrioventricular valves – valve between atria & ventricles  Prevent backflow of blood into atria  Semilunar valves – Exit valves for ventricles  Prevent backflow of blood into ventricles  AV valves close during Ventricular systole  Usually OPEN  Semilunar valves close during Ventricular diastole  Usually CLOSED

Valve Pathologies  Stenosis – valves are too narrow  Does not allow blood to pass  Increased chamber pressure  Regurgitation – incompetent valve  Allows blood to backwash back into previous chamber  End result is excess pressure  Excess pressure wears down cardiac muscle  If uncorrected, Congestive heart failure will occur  Aortic valve stenosis is most dangerous

Electrical Signal Transmission  Sinoatrial (SA) node – Pacemaker of the heart  Located in the upper wall of the right atrium  Sets the rate of cardiac muscle cell contraction  AV node – Delays signals from the SA node  Located in the lower wall of right atrium  Allows atria to completely empty before ventricles contract

Artificial Pacemaker

Cardiac (Heart) Rate  Affected by  Sympathetic nerves – accelerate heart rate  Parasympathetic nerves – decelerate heart rate  Body Temperature  Increase Body temp 1°C  10 beats per minute  Fever  increase in pulse rate  Exercise  Rate increase  Hormones  Epinephrine  Increases heart rate

Questions  1. Once blood leaves the heart, in what order does it go through capillaries, arteries, arterioles, venules, and veins?  2. What is the path of blood in the heart?  3. Explain how heart disease develops?  4. If a patient has a 90% coronary blockage, what treatment is indicated? (Name at least 2)  5. Briefly explain atherosclerosis

Questions (Page 2) 6. Describe the cardiac cycle? 7. Name one of the 2 cardiac valve types 8. Name one of the 2 cardiac valve diseases 9. What is the SA node? (its nickname) 10. Name 3 things that affect heart rate.

Systemic Vascular Pressure  Blood pressure  Typically taken at upper arm cuff  Wrist monitors are not used for diagnostic purposes  2 Types of blood pressure are taken  Systolic  Remember from cardiac cycle?  Vascular pressure when heart has contracted  Diastolic  Remember from cardiac cycle?  Vascular pressure when heart is relaxed

In a typical reading, -- 1 st number is systolic (always larger) -- 2 nd number is diastolic (always smaller) -- Extremely subjective measurement

What regulates or determines blood pressure?  Short- term  Smooth muscle contractions in arterioles  Response to hormonal signals or physical exertion  Skeletal muscles contractions help to propel  Valves in veins prevent backflow  Stress  Long-term  Rennin-angiotensin II-aldosterone system  Vascular constriction - Hypertension

Lymphatic System  Returns lost fluid & proteins to the blood  In the form of lymph  Along lymph vessels are lymph nodes  Filter lymph  Part of immune system  attack viruses and bacteria here  Uses White Blood Cells (WBC)

Blood

Notes on Blood  Plasma  Mostly Water  Ions, electrolytes, & plasma proteins  Transports nutrients, gases, wastes, & hormones  Oh yeah, and it carries Blood Cells  Cellular Constituents  Red Blood Cells (RBC or erythrocytes)  Transports oxygen by hemoglobin  White Blood Cells (WBC)  Part of immune system  Platelets  Cellular fragments responsible for blood clotting

Red Blood Cells  Biconcave discs  Increased surface area enhances O2 transport  250 million molecules of hemoglobin in each RBC  Each hemoglobin = up to 4 O2 molecules  Lack nuclei (more room for hemoglobin)  Lack Mitochondria (so oxygen carried is NOT consumed)

Where do blood cells come from?  Stem cells in the red marrow of flat bones

Clotting

Comparative Circulatory Anatomy