Comprehensive Cardiovascular System: History, Anatomy, Physiology, and Blood Flow

Who is the ancient Greek physician for whom the Hippocratic Oath is named?

Hippocrates

How many books are attributed to Hippocrates?

About 60 books

What did the ancient Greeks believe animated the body?

Natural forces (humors and pneuma), not divine animation

What are the four humors and their associated personality characteristics?

Blood - sanguine (happy, social), Phlegm - phlegmatic (calm, slow), Yellow bile - choleric (angry, aggressive), Black bile - melancholic (sad, depressed)

How did the ancient Greeks believe that the humors controlled health and disease?

Health = balance of humors; Disease = imbalance of humors

What remedies were used to remove disease from someone in ancient Greece?

Bloodletting, purging, vomiting, sweating, diet changes

What did Hippocrates believe happened to the food that people consumed?

It was converted into bodily fluids/blood

Through which vessels did Hippocrates believe blood was carried?

Veins

What did Hippocrates believe the purpose of arteries was?

To carry air (pneuma)

Who became court physician to several Roman emperors and was inspired by Hippocrates?

Galen

What did Galen discover about the difference between arteries and veins?

Arteries have thicker walls than veins

What did Galen discover about the contents of the arteries?

They contain blood

Where did Galen think that food was first transmuted to blood in the body?

The liver

Where did Galen believe that body heat originated from?

The heart

Why did Galen's ideas survive for so long after the fall of the Western Roman Empire?

Church authority, religious acceptance, lack of human dissection

In what city and country was Ibn al-Nafis born?

Damascus, Syria

What did al-Nafis discover about blood flow through the heart that disagreed with Galen?

Blood flows from right heart → lungs → left heart

How did al-Nafis' research change the view of the circulatory system?

He showed a closed circulation between heart and lungs

What did al-Nafis discover about blood delivery directly to the heart?

Coronary circulation supplies the heart muscle

Why was al-Nafis' work slow to reach a European audience?

Language barriers and slow translation

What is a polymath?

A person skilled in many fields; learning was interdisciplinary

Why was human dissection performed at the University of Bologna?

Medical education and anatomical study

What was Leonardo da Vinci's contribution to our knowledge of the circulatory system?

Anatomical drawings and dissections

What did Andreas Vesalius (re)discover about the heart?

The interventricular septum is solid (no pores)

What is Vesalius most well-known for?

De humani corporis fabrica

What two discoveries did Realdo Colombo make?

Pulmonary circulation and rediscovery of pulmonary blood flow

What structures in veins did Girolamo Fabrici discover?

Venous valves

Who proposed that arteries also carried nutrition?

Aristotle

Who was Aristotle's student?

Alexander the Great

How did William Harvey carry out his research?

Experimental scientific method

What tools did Harvey use to trace arteries and veins?

Dissection, ligatures, observation

What did Harvey calculate to determine blood did not come from food?

Cardiac output volume

What did Harvey conclude about blood flow?

Blood recirculates in a closed loop

What did Harvey's contemporaries believe about recirculating blood?

They rejected it

What did Harvey hypothesize the existence of but could not see?

Capillaries

Why was Marcello Malpighi able to discover capillaries?

He had a microscope

What was the discovery made by Malpighi?

Capillaries

What are the three major functions of the cardiovascular system?

Transport, regulation, protection

What are the three components of the transport and delivery function of the cardiovascular system?

Oxygen, nutrients, hormones

What are the four components of the homeostatic regulatory function of the cardiovascular system?

Temperature regulation, pH balance, fluid balance, gas balance

What are the two components of the protective function of the cardiovascular system?

Clotting and immune defense

What are the three major components of the cardiovascular system?

Heart, blood, blood vessels

What proportion of resting blood flow does the heart receive?

~5% of blood flow; ~10% of oxygen

What is a typical cardiac output and what does it depend on?

~5 L/min; depends on heart rate and stroke volume

List the valves of the heart and the areas they separate.

Tricuspid: RA-RV, Pulmonary: RV-pulmonary artery, Mitral (bicuspid): LA-LV, Aortic: LV-aorta

Describe the flow of blood from the vena cava to the aorta.

Vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Pulmonary artery → Lungs → Pulmonary veins → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta

What is the difference between serial and parallel blood flow?

Serial: one pathway after another; Parallel: multiple pathways at the same time

How many functional classifications can the vasculature be separated into?

Five

List and describe the functional classifications of the vasculature.

Arteries: transport blood away from heart, Arterioles: resistance vessels, Capillaries: exchange vessels, Venules: collect blood, Veins: return blood to heart

Which classification has the highest composition of endothelial tissue?

Capillaries

Which classification has the highest composition of smooth muscle?

Arterioles

What happens to blood velocity as it approaches the capillary beds? Why?

It decreases; total cross-sectional area increases

Describe blood pressure across the vasculature.

Pulsatile in arteries; laminar in capillaries and veins

What happens to resistance to blood flow as vessel cross-section gets smaller or larger?

Smaller = increased resistance; Larger = decreased resistance; Resistance drops in capillaries due to massive total cross-sectional area

What two major elements make up the composition of blood?

Plasma (~55%) and formed elements (~45%)

What proportion of plasma volume is taken up by water?

~90%

Which plasma protein is the main contributor to osmotic pressure of the blood?

Albumin

What are gamma proteins in the blood responsible for?

Immune function (antibodies)

What is the importance of fibrinogen in the blood?

Blood clotting

How many chambers are there in the heart?

Four

What property divides the heart into right and left sides?

The septum

Define orthogonal.

Perpendicular

In what anatomical space is the heart located?

Mediastinum

What structures are to the right and left of the heart?

Lungs on both sides

What is immediately inferior to the heart?

Diaphragm below

Describe the location of the base and the apex of the heart.

Base = atria; Apex = left ventricle

What structures anchor the atria and ventricles and support the four valves of the heart?

Fibrous skeleton

What is the significance of the fibrous skeleton to the electrical conduction system of the heart?

Electrical insulation between atria and ventricles

What is another name for the fibrous skeleton?

Cardiac skeleton (annulus fibrosus)

Describe the difference in the structures of the right and left ventricles.

Left ventricle has thicker walls than the right ventricle

What type of hypertrophy is beneficial for the left ventricle?

Physiological hypertrophy is beneficial

What type of hypertrophy is detrimental for the left ventricle?

Pathological hypertrophy is detrimental

List and describe the three layers of myocardium that surround the ventricles.

Outer longitudinal, middle circular, inner longitudinal; produces twisting/squeezing motion

Describe the difference in the contraction of the right and left ventricles.

LV twists; RV squeezes

Define the cardiac cycle.

One complete heartbeat

List the two phases of the cardiac cycle.

Systole = ventricles contracting; Diastole = ventricles relaxing

List the two periods of systole and the two periods of diastole.

Systole: isovolumetric contraction, ejection; Diastole: isovolumetric relaxation, ventricular filling

What is the significance of ******'s diagram?

Shows electrical, mechanical, and pressure changes in one heartbeat

What does the x-axis of ******'s diagram represent?

Time

During ventricular filling, which valves are open?

Open: tricuspid, mitral

During ventricular filling, which valves are closed?

Closed: pulmonary, aortic

During isovolumetric contraction, which valves are open?

All valves closed

During ejection, which valves are open?

Open: pulmonary, aortic

During ejection, which valves are closed?

Closed: tricuspid, mitral

During isovolumetric relaxation, which valves are open?

All valves closed

What signals the beginning and end of ventricular filling?

Begin: AV valves open; End: AV valves close

What signals the beginning and end of isovolumetric contraction?

Begin: AV valves close; End: semilunar valves open

What signals the beginning and end of ejection?

Begin: semilunar valves open; End: semilunar valves close

What signals the beginning and end of isovolumetric relaxation?

Begin: semilunar valves close; End: AV valves open

At the end of diastole, what is atrial contraction called?

Atrial systole

For a valve to open or close, what must exist across the valve?

A pressure gradient

When are aortic pressure and left ventricular pressure equal?

At valve transition points (opening/closing of aortic valve)

If pressure inside the aorta rose above pressure in the left ventricle, which valve would close?

Aortic valve

If pressure inside the right ventricle rose above pressure inside the right atrium, which valve would close?

Tricuspid valve

Which phase is longer at rest, systole or diastole?

Diastole

Define ESV, EDV, and SV.

ESV = end-systolic volume; EDV = end-diastolic volume; SV = stroke volume

How is SV calculated?

SV = EDV − ESV

When is LV volume greatest?

Greatest: end of diastole (ventricular filling)

When is LV volume lowest?

Lowest: end of systole (ejection)

Define ejection fraction.

EF = % of blood ejected per beat