2. General Information
• What makes a circulatory system necessary?
-small organisms lack a circulatory system
because diffusion is a sufficient means for
exchanging gases and transporting materials
-larger organisms need circulatory system
because all of their cells are not in direct
contact with the environment and they need to
transport substances made in one part of
organism to other areas
• What are makes up human circulatory system?
-heart, blood vessels, and blood

3. Functions of Circulatory
System
• Delivery jobs:
-nutrients
-oxygen
-water and vitamins
-hormones
• Pick up jobs:
-CO2 and carry to lungs
-wastes and carry to kidneys
• Other jobs:
-maintain homeostasis (body temp.)
-protect body from disease

4. Composition of Blood
• 55% plasma, 45% cells

5. Composition of Blood
• Plasma:
-non-living
-90% water
-10% proteins, waste, dissolved gases, salts,
nutrients, and hormones
-3 Types Plasma Proteins:
1) albumin – regulates osmotic pressure,
transports fatty acids, hormones, vitamins
2) globulin – helps fight infection (antibodies)
3) fibrinogen – helps clot blood

6. Composition of Blood
Cellular Portion
• Red blood cells
-“erythrocytes”
-transport oxygen
-contain hemoglobin
protein that carries iron
which binds with oxygen
• People with iron poor diets become anemic. Iron
aids in production hemoglobin.

7. Composition of Blood
Cellular Portion
• White blood cells
-“leukocytes”
-destroys pathogens
-makes antibodies
-stored in spleen, tonsils,
lymph nodes
• -Leukemia is cancer of white blood cells
(abnormal division of WBC’s).

8. Composition of Blood
Cellular Portion
• Platelets
-cell fragments
-useful clotting blood
• *Hemophiliacs problems
with blood clotting =
excessive bleeding
• *Stroke is an abnormal
blood clot blocks blood
flow to areas of brain

9. Blood Clotting
• Platelets contact edge
of broken blood vessel
“stick”= platelet plug
• Platelets release
clotting factor called
thromboplastin converts
prothrombin
thrombin
• Thrombin (enzyme)
converts fibrinogen 
fibrin
• Fibrin filaments create
a “sticky mesh” acting
like a net catching RBC
to stop bleeding

10. Blood Vessels
• Blood travels through the body inside of vessels
(closed circulatory system)
• 3 Types of blood vessels
1) Arteries
-carry O2 rich blood away from the heart
-thick walls to with stand pressure
-largest artery is aorta
2) Veins
-carry O2 poor blood back toward heart
-contain valves help keep blood moving to heart
(varicose veins)
-largest vein is vena cava

11. Blood Vessels cont.
3) Capillaries
-connect veins and arteries
-extremely thin, only 1 cell thick
-O2/nutrients diffuse from here
into tissues and CO2/wastes
diffuse back into here

12. Blood Vessels

13. Human Heart
• Muscular
organ- pumps
blood
• Enclosed in a
protective sac
called
pericardium

14. Structures of Heart
• Mammals have a 4 chambered heart
• Atria (atrium)- “upper chambers” collect
blood coming to heart
• Ventricles- “lower chambers” pump blood
out of the heart
• Chambers separated by valves- prevent
blood from flowing backwards
• Septum- thick muscle divides right/left
halves

15. Flow of Blood Through Heart
• Right Side (oxygen-poor)
-enters vena cava
-collects in the right atrium
-through tricuspid valve
-into right ventricle
-carried by pulmonary arteries to
lungs
***Pulmonary artery is the ONLY artery in
the body that carries oxygen poor blood

16. Flow of Blood Through Heart
• Left Side (oxygen-rich)
-leaves lungs, carried to heart by
pulmonary veins
-enters left atrium
-through bicuspid valve into
left ventricle
-forced into aorta, carried rest
of body

17. Heartbeat
• Muscle fibers through out heart
stimulate contraction
• Right atrium (sinoatrial node) sends
electrical impulses that starts wave
of muscle contraction = pacemaker
• Ventricular node receives
contraction impulse and wave and
spreads through ventricles

18. Pathways of Circulation
• Pulmonary circulation- carries blood
between heart and lungs
• Systemic circulation- carries blood
from heart to rest of the body

20. Blood Pressure
• Measure of the force blood against
the walls of arteries
• Pressure helps blood circulate body
• Systolic- measures force blood in
arteries when ventricles contract
• Diastolic- measures force blood in
arteries when ventricles relax
• Healthy blood pressure reading is
about 120/80

21. Cardiovascular Disease
• Disease of heart and blood vessels
• High levels of blood lipids may indicate high risk
of heart disease.
• Cholesterol is a lipid.
• 2 Types Cholesterol:
-LDL “bad cholesterol” deposits on walls of
arteries = “plaque”
-HDL “good cholesterol” carried back to liver
for removal from body
• Atherosclerosis- condition caused by build up
fatty deposits on wall arteries
• Hypertension- condition in which blood pressure
is constantly too high
• Both conditions put person increased risk for
heart attack and stroke

22. Lymphatic System
• Network of vessels, nodes, and organs
• Function:
1) collects fluid lost by blood and returns
back to circulatory system
2) filter fluid
3) Absorb fats and vitamins from
digestive tract and carry them to blood

23. Components of
Lymphatic System
• Lymph = “fluid”
• Lymph vessels – collect
fluid and return to vena
cava (circulatory
system)
• Edema- swelling due to
blocked lymph vessels
• Lymph nodes- filter and
trap bacteria and other
microorganisms
• “Swollen glands”
• Thymus and Spleen

24. Respiratory System
• Respiration- process of gas exchange
(carbon dioxide/oxygen) between the
cells, blood, and lungs and environment
• Structures of Respiratory System:
1) Nose
2) Trachea (pharynx/larynx)
3) Bronchi
4) Lungs

25. Mechanism for Breathing
• Involves the movement air into and out of lungs
• Diaphragm- muscle separates thorax (chest
cavity) and abdomen helps inhale and exhale air
• Pathway air flow and gas exchange:
1) Air enters the nose and mouth
(filtered, moistened, warmed)
2) Pharynx and larynx (vocal cords)
3) Trachea (wind pipe)
4) Bronchi (large tube leads to each lung)
5) Lungs  bronchioles  aveoli (air sacs
where gas exchange occurs)

26. Structure of Lungs