Cardiovascular System Notes:The Heart

The human heart creates enough pressure to squirt blood 30 feet.

Interesting Cardiovascular System Facts

Review

What are the 3 parts of the cardiovascular system?

heart – blood – blood vessels

What do arteries do?

Take blood AWAY from the heart

What are the 3 layers of an artery?

What do veins do?

Bring blood TOWARD the heart

What do veins have that arteries don’t?

VALVES – (veins & arteries both have the same layers

except the muscular layer is smaller)

Tunica externa /connective tissue (elastin) – tunica

media/smooth muscle – tunica intima/endothelium

What exchanges material between blood and the body’s cells?

CAPILLARIES

How big are they?

microscopic in size

NOTES – THE HEART

• Location: • cavity between the lungs, 2/3 left of

midsagittal

• roughly the size of a fist

• Heart Anatomy

• PERICARDIUM • outer membrane of the heart

• 2 layers 1. Parietal pericardium: external

(outer) layer

2. Visceral pericardium (epicardium):

part of the heart wall

• Functions: • protection – physical barrier

• anchors heart to other structures

• provides lubrication to reduce

friction – allows the heart to beat

easily

1. Epicardium: outer portion

(visceral pericardium)

• 3 layers

• THE HEART WALL

EPICARDIUM

2. Myocardium: middle layer

consists of twisted cardiac

muscle

• THIS IS THE LAYER THAT

ACTUALLY CONTRACTSMYOCARDIUM

3. Endocardium: inner layer

made of epithelial tissue

ENDOCARDIUM

• HEART CHAMBERS

• 4 chambers

• Atrium (left/right

atria)

• divided by the INTERATRIAL

SEPTUM

• Function of Atria: receives blood

from veins

(pig heart)

• RIGHT ATRIA • receives blood from superior &

inferior vena cava

• blood that’s been used

• oxygen poor – high in CO2

• receives blood from

pulmonary veins

• LEFT ATRIA

• coming from lungs

• rich in oxygen

• Ventricles

(left/right)

• muscular pumps – divided by

INTERVENTRICULAR SEPTUM

(pig heart)

• RIGHT VENTRICLE • receives blood from the right atria (O2

poor)

• pumps blood to the lungs through the

PULMONARY ARTERIES

• LEFT VENTRICLE • receives blood (O2 rich) from the left

atrium

• pumps blood to the body through the

AORTA

• Systemic Circulation • heart – lungs – heart –

body – heart

• HEART VALVES (4) • allow for “one way” circulation

• 2 Atrioventricular

Valves (AV valves)

1. Tricuspid Valve: between right atria

and right ventricle

2. Bicuspid or Mitral Valve: between

left atria and left ventricle

• heavier & stronger of the two

• CHORDAE TENDINAE and papillary

muscles stop valves from being folded

backwards

CHORDAE TENDINAE

3. Pulmonary Semilunar Valve: between the

pulmonary artery and right ventricle

4. Aortic Semilunar Valve: between aorta

and left ventricle