Cardiovascular DiseaseChapter 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 killerWhat do arteries do?

-- Carry blood away from heart (oxygenated blood)

Why is oxygenated blood important?

-- Oxygen allows respiration to take place

Arterial Disease = #1 killerPage 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 SystemBlood 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 Anatomyhttp://www.pbs.org/wnet/heart/tour/index.html

Cardiac CycleConsists 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 ValvesAtrioventricular 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 TransmissionSinoatrial (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) RateAffected 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,-- 1st number is systolic (always larger)-- 2nd 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 SystemReturns 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 BloodPlasma

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