APK4120 Final?

The circulatory system worsened with the ____.

pulmonary system (cardiopulmonary or cardiorespiratory system)

Purposes of the cardiorespiratory system (3)

• Transport O2 and nutrients to the tissues.

• Removal of CO2 wastes from tissues.

• Regulation of body temperature.

The circulatory system is composed of the (4)

• Heart

• Arteries and arterioles

• Veins and venules

• Capillaries

The heart creates ____.

pressure to pump blood

Arteries and arterioles carry blood ____ from the heart.

away

Veins and venules carry blood ____ the heart.

toward

Capillaries are responsible for all ____.

exchange of O2, CO2 and nutrients with tissues.

The heart wall is composed of the (3)

• Epicardium

• Myocardium

• Endocardium

The myocardium "muscle" is responsible for ____.

heart contraction

Myocardium received blood supply via ____.

coronary arteries

____ responsible for meeting high demand for oxygen and nutrients.

Coronary arteries

Myocardial infarction (MI) (2)

• Blockage in coronary blood flow results in cell damage.

• Exercise training protects agains heart damage during MI.

Epicardium (visceral pericardium): Characteristics

Serous membrane including blood capillaries, lymph capillaries, and nerve fibers.

Epicardium (visceral pericardium): Function

Serves as lubricative outer covering.

Myocardium: Characteristics

Cardiac muscle tissue separated by connective tissues and including blood capillaries, lymph capillaries, and nerve fibers.

Myocardium: Function

Provides muscular contractions that eject blood from the heart chambers.

Endocardium: Characteristics

Endothelial tissue and a thick subendothelial layer of elastic and collagenous fibers.

Endocardium: Function

Serves as protective inner lining of the chambers and valves.

Physical characteristics of blood (2)

1. Plasma

2. Cells

Plasma is ___ and contains ____ (3)

-Liquid portion of blood.
-Contains ions, proteins, hormones.

Cells (3)

• Red blood cells (RBC)

• White blood cells

• Platelets

Red blood cells (RBC) (2)

• Contains hemoglobin to carry oxygen.

• Largest fraction of cells in the blood.

White blood cells

Important in preventing infection.

Platelets

Important in blood clotting

Hemoatocrit

Percentage of blood composed of RBC. Most people have 40-42%.

Systole (2)

• Contraction phase

• Ejection of blood

____ of blood is ejected from ventricles per beat.

Approximately 2/3

Diastole (2)

• Relaxation phase

• Filling with blood

At rest, ____ is longer.

diastole

During exercise, both systole and diastole are ____.

shorter

Diastole (rest) (2)

• Pressure in ventricles is low.

• Filling with blood from atria.

Systole (contraction) (2)

• Pressure in ventricles rises.

• Blood ejected in pulmonary and systemic circulation.

First heart sound

Systole (closing of AV valves)

Second heart sound

Diastole (closing of aortic and pulmonary valves)

Systolic pressure

Generated during ventricular contraction.

Diastolic pressure

Pressure in the arteries during cardiac relaxation.

Pulse pressure

Difference between systolic and diastolic pressure.

Mean arterial pressure (MAP)

Average pressure in the arteries during cardiac cycle at REST.

Contraction of the heart depends on electrical stimulation of the ____.

myocardium

Electrical activity of the heart: Conduction system (4)

• Sinoatrial node (SA node)

• Atrioventricular node (AV node)

• Bundle branches (extend from AV node)

• Purkinje fibers

Sinoatrial node (SA node)

Pacemaker, initiates depolarization.

Atrioventricular node (AV node) (2)

-Passes depolarization to ventricles

-Brief delay to allow for ventricular filling (blood transfer from atria to ventricles).

Bundle branches (extend from AV node)

Connect atria to left and right ventricle.

Purkinje fibers

Spread wave of depolarization throughout ventricles.

Regulation of HR (3)

• Parasympathetic nervous system

• Sympathetic nervous system

• Increase in HR at onset of exercise

Parasympathetic nervous system (3)

• Via vagus nerve

• Slows HR by inhibiting SA and AV node.

• Decrease in parasympathetic tone = increase in HR (this typically causes rise in HR up to 100 bpm).

Sympathetic nervous system (2)

• Via cardiac accelerator nerves.

• Increases HR by stimulating SA and AV node (this typically causes rise in HR beyond 100 bpm).

Increase in HR at onset of exercise (2)

• Initial increase due to parasympathetic withdrawal.

• Later increase due to increased SNS stimulation.

Heart rate variability (3)

• The time between heart beats.

• Standard deviation of the R-R internal on an EKG.

• Balance between SNS and PNS.

Wide variation in HRV is considered

health (reflects "autonomic balance")

Low HRV is a predictor of cardiovascular ____.

morbidity and morality, especially in patients with existing cardiovascular disease.

Cardiac output (3)

• The amount of blood pumped by the heart each minute.

• Product of heart rate x stroke volume.

• Depends on training state and gender.

Stroke volume

Amount of blood ejected in each beat.

End-Diastolic volume (2)

-Volume of blood in the ventricles at the end of diastole (aka "preload").

-Dependent on venous return.

Frank-Starling Mechanism

Greater EDV results in a more forceful contraction. Due to the stretch of ventricles.

Venous return is increased by (3)

• Venoconstriction

• Skeletal muscle pump

• Respiratory pump

Venoconstriction

Increased pressure in veins.

Skeletal muscle pump

Rhythmic skeletal muscle contractions force blood in the veins towards the heart.

Respiratory pump

Changes in thoracic pressure pull blood towards heart.

Regulation of stroke volume is dependent on (3)

• End-diastolic volume (EDV)

• Average aortic blood pressure

• Strength of the ventricular contraction (contractility)

Average aortic blood pressure

Pressure the heart must pump against to eject blood ("afterload"). MAP

Strength of the ventricular contraction (contractility)

Enhanced by: Circulating epinephrine and norepinephrine and Direct sympathetic stimulation of heart.

Oxygen demand by muscles during exercise is ____ greater than at rest.

15-25x

Increased O2 delivery accomplished by (2)

1. Increased cardiac output

2. Redistribution of blood flow (from inactive organs to working skeletal muscle)

Cardiac output increases due to

Increased HR and SV

HR during exercise (3)

• Linear increase to max

• For adults 220-age

• For kids 208-0.7 x age

SV during exercise (2)

• Increase, then plateau at 40-60% VO2 max.

• No plateau in HIGHLY trained subjects.

Changed in HR and BP during exercise depend on (4)

• Type, intensity and duration of exercise (arm vs leg exercise)

• Environmental condition (hot/humid vs cool)

• Emotional influence

• Training status

At the same oxygen uptake, arm work results in higher (2)

-HR: due to higher sympathetic stimulation.

-BP: due to vasoconstriction of large inactive muscle mass.

At the onset of exercise (2)

-Rapid increase in HR, SV and Q.

-Plateau in submaximal (below lactate threshold) exercise.

During recovery from exercise (2)

-Decreased in HR, SV and Q towards resting levels.

-Depends on: Duration and intensity of exercise, Training state of subject.

Regular exercise is cardioprotective (2)

• Reduces incidence of heart attacks.

• Improves survival from heart attack.

Exercise reduces the amount of myocardial damage from heart attack (2)

-Improvements in heart's antioxidant capacity (ability to remove free radicals).

-Improved function of ATP-sensitive potassium channels.

Cardiovascular disease (CVD) includes (4)

• Coronary heart disease (CHD)

• Heart failure

• Hypertension

• Stroke

____ is the leading cause of death in the U.S.

Cardiovascular disease

Approximately ____ of all CVD deaths are from CHD.

50%

Every ____ in the U.S., someone suffers a heart attack.

42 seconds

Average of first MI is ____ (m/f).

65 for men, 72 for women

Acute coronary syndromes (ACS) include (3)

1. Unstable angina pectoris (chest pain)

2. Acute myocardial infarction (heart attack)

3. Potentially sudden cardiac death

Unstable angina pectoris (chest pain)

Result of ischemia (decreased blood flow/oxygen).

Acute myocardial infarction (heart attack) (2)

• Death of cardiac muscle cells due to prolonged ischemia.

• Occlusion for 60+ minutes.

Potentially sudden cardiac death (2)

• Abrupt loss of heart function caused by electrical disturbance.

• Electrical disturbance may be triggered by MI.

Artery layers: Endothelium

Innermost layer; protects against antherothrombosis.

Artery layers: Intima

Thin layer of connective tissue on tome of endothelium; Formation site of atherosclerotic lesions.

Artery layers: Media

Located on time of intima; contains mainly smooth muscle cells along with some connective tissue.

Artery layers: Adventitia

Outermost layer; contains connective tissue fibroblasts, and a few smooth muscle cells.

Atherogenesis

Disease process that may result in blood flow- limiting lesions in the: Epicardial coronary, carotid, iliac, femoral arteries, aorta.