THE CIRCULATORY AND RESPIRATORY SYSTEMS

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

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 

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

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

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.

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

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.

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

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

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

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. Do we need the types of respiration at the bottom here? TH I can live with that! CAI

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)

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.

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. Pix p. 946 a ???????CAI

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.

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.