Transcript Cardiovascular System: - Hinsdale Township High School

Cardiovascular Structure
Why do we need a CV system?
 The heart pumps blood and blood vessels transport
blood, so that
 Oxygen reaches all cells of the body
 Carbon dioxide reaches the lungs to be exhaled
 What other vital components are carried through the
blood vessels (in the blood)?
 Nutrients
 Hormones
 WBC’s
Blood flows through 60,000 miles of vessels!
CV system continued
 What happens when the blood vessels of your
extremities & body surface—
 Vasodilate? (widen)

Blood travels to these areas, releasing heat
 Vasoconstrict? (narrow)

Blood travels to the core, conserving heat
 Therefore: CV system is also important for
temperature regulation
Summary
 Structures of the CV System
 Heart
 Blood Vessels



Arteries, arterioles
Veins, venules
Capillaries
 Functions of the CV System
 Transport
 Temperature regulation
Let’s start with the HEART
 Shape: Triangular
 Size: Closed Fist
 Location:
 2/3 to the left of the midline
 1/3 to the right
 Apex sits on the diaphragm
X & 0 are two common areas where heart
sounds are checked
Chambers of the Heart
 Two upper chambers– atria (pl.)
 Right atrium
 Left atrium
 Receive blood
 Two lower chambers- ventricles
 Right ventricle
 Left ventricle
 Pump blood
Based on the functions of the atria vs. the
ventricles, how do you think their structures
differ?
 Because ventricles pump blood and atria simply
receive it, ventricles must have THICK MUSCULAR
walls.
Heart Structure: Layers
 Inner lining:
endocardium.
 Wall of the heart:
myocardium
(cardiac muscle tissue)
 Outer lining:
epicardium
 Same as the visceral
pericardium
 Legend: M - myocardium; E - endocardium;
En - endothelium; S - subendothelial layer
 What layer lies outside of the myocardium?
 What is another name for this layer?
Pericardium: Outer Sac surrounding the
heart, composed of two layers
 Visceral pericardium (layer
closest to the heart, also
called the epicardium)
 Parietal pericardium
(outermost layer)
 Lubrication b/w layers
reduces friction