1. The Circulatory System
Biology

2. Circulatory System outline
2. veins (venules)
3. capillaries
Heart
A. Chambers
B. Flow (picture)
Blood pressure
A. Systolic
B. Diastolic
C. pulse
Why need circulation?
Blood
Plasma
Cells
1. red
2. white
3. platelets
Vessels
1. arteries (arterioles)

3. Why do we need circulation?
Diffusion is too slow to transport nutrients and oxygen to and remove wastes from all body cells.

4. 55% plasma (straw colored); 45% cells
Blood
Blood = the fluid that carries these needed materials to all body parts
55% plasma (straw colored); 45% cells

5. Red blood cells (erythrocytes: contain hemoglobin to carry oxygen
Types of blood cells:
Red blood cells (erythrocytes: contain hemoglobin to carry oxygen
White blood cells (leukocytes: defend body against foreign invaders such as disease
Platelets: initiate blood clotting, bits of cytoplasm from bone marrow cells

6. Circulatory disorders
Anemia: low number of red blood cells, tired, infections because cells do not get enough oxygen
Hemophilia: blood doesn’t clot properly
Thrombus: blood clot when no injury, can lead to heart attack if blocks coronory artery

7. Blood travels through vessels:
Arteries (arterioles): carry blood away from the heart; therefore thicker walls due to extreme pressure
Veins (venules): carry blood to heart;
contain valves to prevent backflow
of blood
Capillaries: smallest blood vessels where nutrients and gases are exchanged with tissues

8. Heart Pumps blood throughout the body
Mammalian hearts have 4 chambers: 2 atria (upper chambers) and 2 ventricles (lower chambers)
Blood enters the atria and leaves through the ventricles; how blood travels:

9. Make drawing:

10. Left Atrium
Right Atrium
Valves
Left Ventricle
Right Ventricle

12. Blood Pressure Force that the blood exerts on the blood vessels:
Systolic: first (highest) number; ventricles contract to push blood through arteries
Diastolic: second (lower) number; ventricles relax as they refill with blood

13. Surge of blood through an artery (stretching of artery)
Pulse
Surge of blood through an artery (stretching of artery)
Pacemaker: everyone has a natual one in right atrium, sets heart rhythm

14. Circulatory disorders
Heart murmur: when blood travels backward through valve in heart, makes hissing sound, not always serious
Heart attack: death of cardiac muscle cells, no oxygen to body
when heart muscles die, not replaced
(cardiac muscle cells do not divide) so
scar tissue forms and heart is permanently
damaged

15. Circulatory disorders
high blood pressure (hypertension) caused by blockage of artery, heart works harder
atherosclerosis: plaques (lipids) develop on inner walls of arteries, causes chest pain (angina)
arteriosclerosis: hardening of the arteries

16. Review questions
What component of blood is responsible for helping your blood clot?
Why are the walls in ventricles thicker and more muscular than the walls in the atria?
What is the job of valves in veins?