Download Circulatory System - Holy Trinity Diocesan High School

Circulatory System
A. Function:
 Circulates nutrients (C6H12O6), oxygen and wastes from
one area of the body to another
B. Structures:
1. Heart
o Four chambered muscle
a. Atria:
 Top 2 chambers of the heart (left and right)
separated by valves
 Receive blood from the lungs or body
b. Ventricle:
 Bottom 2 chambers of the heart (left and
right) separated from the atria by valves
 Pump blood out of the heart to the lungs or
body
 Right Side:
 Receives deoxygenated blood from the body
and pumps it to the lungs to get rid of CO2
 Left Side:
 Receives oxygenated blood from the lungs
and pumps it to the body
2. Vessels:
a. Arteries:
 Carry blood from the heart to the body or
the lungs
b. Capillaries:
 Vessels that are extremely thin (1 cell thick)
 Connect arteries and veins
 Diffusion of oxygen, nutrients and wastes
between the circulatory system and all body
cells
c. Veins:
 Carry blood from the body or lungs to the
heart
3. Blood:
 Made of cells and fluid
b. Red Blood Cells (RBC):
 Disk shaped cells lacking a nucleus
 Hemoglobin = iron-containing protein that
carries oxygen
 45% of the blood
c. White Blood Cells (WBC):
 Large cells involved in the immune response
 <1% of the blood
d. Platelets:
 Cell fragments that clot the blood by
releasing proteins
 <1% of the blood
e. Plasma:
 Clear liquid portion of the blood
 Carries all of the cells throughout the system
 55% of the blood
C. Blood Flow
1.
Pulmonary Circulation
 Blood flowing to and from the lungs
a.
Deoxygenated blood enters the superior
and inferior vena cava (veins) from the
body
b.
c.
Blood enters the right atrium, passes
through the tricuspid valve, to the right
ventricle
Blood is then pumped to the pulmonary
arteries to the lungs for gas exchange at
the capillaries
2. Systemic Circulation:
 Blood flowing from the lungs through the
heart to the body
a.
b.
c.
Pulmonary veins carry oxygenated blood back
to the heart
Blood enters the left atrium through the
bicuspid valve, to the left ventricle.
Blood is pumped out of the heart through
the aorta to the body carry oxygen
C. Disorders:
1.
High Blood Pressure:
 Elevated blood pressure; the heart has to work
harder to perform normal tasks
2.
Heart Attack:
 Portion of the heart dies due to lack of oxygen
usually due to high blood pressure
 Disrupts homeostasis by decreasing the circulation
of blood throughout the body
3.
Cardiovascular Disease:
 Arteries become clogged due to high cholesterol
 Disrupts homeostasis by causing a blockage to the
heart or decreased blood flow throughout the body
4.
Stroke:
 Blood clot in the brain causing a lack of oxygen and
brain damage
 Disrupts homeostasis by not allowing the nervous
system to regulate body functions