1. Circulatory and Respiratory Systems Biology

2. Vertebrate Circulatory System Closed system with a chambered heart that pumps blood through arteries that lead away from the heart to capillaries. Capillaries—small vessels in tissues where exchange of materials take place Blood is carried back to heart through veins

3. Human Heart Located beneath the sternum About the size of your fist Composed mostly of cardiac muscle tissue 2 atria have thin walls and function as collection chambers for returning blood 2 ventricles have thick, powerful walls that pump blood to the organs

4. Blood Vessels Arteries—carry blood away from the heart to the tissues –Branch into smaller arterioles, which supply blood to tissues via capillaries –Thick-walled, muscular (smooth muscle), and elastic, transporting blood at high pressure –Blood is oxygenated, except the pulmonary artery that carries deoxygenated blood from tissues to lungs through the right atrium and ventricle

5. Veins—carry blood to the heart from the capillaries –Capillaries branch into larger venules, which supply blood to veins and back to the heart –Thin-walled, little smooth muscle, transporting blood at low pressure, and contain many valves to prevent backflow –Veins have no pulse and carry deoxygenated blood, except the pulmonary vein which carries oxygenated blood from the lungs –Skeletal muscle contraction aids in systemic circulation

6. Capillaries—thin- walled vessels (simple squamous) Permit exchange of materials between blood and body cells

7. Capillaries Fluid containing water with nutrients and hormones seep from capillaries into tissues, driven by pressure Cells and proteins are retained in the capillaries and draw water back into the capillaries by osmosis Excess fluid in tissue can enter lymphatic system to be filtered and cycled back to the circulatory system

8. Blood Components

9. Erythrocytes: Red Blood Cells Primary function to carry oxygen Produced in red bone marrow of bones Mature cells lack nuclei and circulate ~4mos. Mature cells lack mitochondria—produce ATP without oxygen through glycolysis Contain hemoglobin-pigment that binds oxygen

10. Erythrocytes: Red Blood Cells Red blood cells (rbc) manufacture 2 antigens, antigen A (Blood Type A) and antigen B (Blood Type B) –No antigens create the Blood Type O Plasma carries antibodies for the antigens that are not present on the rbc s

11. Leukocytes: White Blood Cells Involved in immune functions in the body –Phagocytes—engulf bacteria –Lymphocytes (B and T cells)—immune response B cells produce antibodies Helper T cells kill infected cells

12. Leukocytes: White Blood Cells Platelets—cell fragments produced in marrow –Involved in blood clotting mechanism –Activation of a protein in the blood, fibrin, that forms a net across the wound, trapping more cells and blocking the flow of blood

13. –Pulmonary circulation Pumps oxygen-poor blood through pulmonary arteries to the lungs Pick up O 2 /Unload CO 2 Oxygenated blood returns to left side of heart through pulmonary veins –Systemic circulation Pumps oxygen-rich blood through arteries to the tissues of the body Delivers O 2 /Picks up CO 2 Returns deoxygenated blood to right side of heart through veins Two separate circulatory loops

14. –Atrioventricular valves Prevent backflow when ventricles contract –Semilunar valves Prevent backflow when ventricles relax Four valves function to prevent backflow of blood

16. Control of Heart Rhythm Sinoatrial (SA) node—cells are self- excitable—generate electrical impulses Cardiac muscle cells are electrically coupled by intercalated discs b/w cells

17. Control of Heart Rhythm Atrioventricular (AV) node—receives signal from atria, delays 0.1 sec, and then sends signal throughout walls of ventricle

18. Cardiovascular Disease Heart attack—death of cardiac muscle tissue resulting from artery blockage of one or more coronary arteries which supply oxygen to the heart Stroke—death of nervous tissue in the brain resulting from artery blockage in the head

21. Ventilating Lungs: Breathing

22. Automatic Control of Breathing Breathing control center in brain = medulla oblongata and pons Monitors CO 2 levels in blood by changes in pH –CO 2 + H 2 O  Carbonic acid –  pH =  depth and rate of breathing  altitude =  O2 levels Sensors in aorta and carotid arteries detect and signal control center to  breathing rate

23. Loading and Unloading of Respiratory Gases

24. Oxygen Transport Oxygen carried by respiratory pigments –Vertebrates utilize hemoglobin—four heme groups surrounding an Fe atom Can carry four oxygen atoms

25. Carbon Dioxide Transport Hemoglobin transports CO 2 and assists with buffering the blood—prevents dramatic changes in pH 7% CO 2 released by cells transported as dissolved CO 2 in plasma 23% binds to amino group of hemoglobin in red blood cells 70% transported in form of bicarbonate ions

27. Emphysema Alveoli lose their elasticity Makes it difficult to release air during exhalation Person must use more and more energy just to breathe Person suffers from constant fatigue and breathlessness

28. Lung Cancer Abnormal cell growth Affected lung is usually removed Fewer than 10% of lung cancer victims live more than 5 years