1. THE CIRCULATORY AND RESPIRATORY SYSTEMS

2. The Circulatory System
The circulatory system contains the network of blood vessels that connects the organs and muscles of the body, the muscular heart that pumps the blood and the lymphatic vessels that collect excess fluid.
The circulatory system:
transports food, oxygen, wastes
transports hormones
helps defend the body
helps distribute body heat

3. Components of Circulatory System
There are four major components of the human circulatory system:
blood vessels - network of tubes that carry blood
lymphatic vessels - recover fluid that leaks out of blood vessels
blood - connective tissue of cells and fluid
heart - pumps blood throughout body
Blood clotting 

4. Blood Vessels There are three main vessels:
arteries - thick, muscular walls
carry blood away from heart
blood pulses
veins -less muscular walls
valves prevent back flow
carry blood toward heart
capillaries - link arteries and veins
walls only one cell thick
narrow diameter - RBC line up single file to pass 
where actual exchange of materials takes place

5. Patterns of Circulation
General circulation path of blood:
heartarteries arterioles capillaries venules veins heart

6. Patterns of Circulation
Pulmonary circulation - pumping blood from heart to the lungs & back to heart.
Systemic circulation - blood is pumped from heart to the body’s tissues & back to heart.
Coronary circulation - supplies blood to the heart muscle itself.

7. The Heart The Heart The central organ of the cardiovascular system
A double pump
upper chambers = atria
lower chambers = ventricles
Within the thoracic cavity

8. Control of the Heartbeat
Contraction of the heart is initiated by a small cluster of cardiac muscle cells embedded in the right atrium.
This “pacemaker” of the heart is called the sinoatrial node (SA node).
These cells initiate their own electrical impulse and cause the atria to contract.
After this initiation the impulse then travels to the AV node to contract the ventricles.

9. Cardiovascular Functions
Cardiovascular functions can be monitored:
pulse = heart rate
blood pressure is measured with a sphygmomanometer; relaxation of heart = diastolic; contraction of heart = systolic pressure (Normal = 120/80)
electrical impulses produced by the heart muscle is measured with an EKG

10. Blood The blood has two main components:
plasma - liquid portion (60% by volume)
90% water; 10% solutes such as proteins, glucose, salts
cells & cell fragments (40% by volume); three types:
red blood cells (RBC) - erythrocytes
5M/ml
contain hemoglobin; carry oxygen
white blood cells (WBC) - leukocytes
8,000/ml ( during infection)
defend body against disease, invasion
platelets - thrombocytes
release fibrin to help blood clot
RBC
WBC
Platelet

11. Cardiovascular Diseases
high blood pressure (hypertension)
heart attack
atherosclerosis (build-up of plaque )
arteriosclerosis ( loss of elasticity)
stroke

12. The Respiratory System
It is the function of the respiratory system exchange gases with the atmosphere and to transport these gases to and from the circulatory system.
Remember that the body requires O2 and creates CO2 in the process of cellular respiration.
There are two places where gas exchange takes place
Between the lungs and blood vessels
Between the blood vessels and the tissues.
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13. The Respiratory System
Air is carried to the lungs by way of a branched system of tubes and air sacs.
Path of air through respiratory system:
nostrils - air is warmed, moistened and filtered
pharynx - upper throat
larynx - voice box
trachea - covered by epiglottis
tube reinforced with cartilage; divides into bronchi
bronchi - divide into bronchioles
bronchioles - enter lungs
lungs with alveoli (air sacs)

14. Alveoli
The end of the air passageway are air sacs surrounded by capillaries.
This is where gas exchange in the lungs takes place.
The alveoli are designed to increase surface area for gas exchange.

15. Gas Exchange- O2
Oxygen molecules diffuse from the alveoli into the blood plasma where it is picked up by RBC, containing hemoglobin (Hb).
Oxygen is transported to tissues where the O2 levels are lower  O2 is released from Hb.
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16. Regulation of Breathing
The amount of O2 needed (and CO2 produced) by the body depends upon the activity of the cells.
It is involuntary.
Breathing rate is controlled by amount of CO2 in blood (not the amount of O2)
The respiratory control center of brain regulates breathing rate.

17. Mechanism of Breathing
Breathing is the result of pressure changes inside the thoracic cavity.
During inhalation/inspiration, the diaphragm contracts, moves downward, the ribs move up and out causing an increase in the size of the cavity  a decrease in pressure inside the lungs.
The higher air pressure outside body allows air to enter the lungs.
During exhalation/expiration, the diaphragm and ribs return to original position, causing a decrease in size of cavity causing an increase in air pressure inside lungs.
This forces air from the lungs.