Chapter 42 Reading Quiz 1.Circulatory systems all have three basic components: Blood, _____, & ___ _____. 2.Which region of the heart is the pacemaker? 3.Insects use what system for respiration? 4.What is the name of the sheet of muscle that forms the bottom wall of the chest cavity?

1. Why are circulation and respiration talked about in the same chapter? How are they related? The circulatory system connects the body cells to the organs that exchange gases - transports fluid throughout body - functionally connects this aqueous environment with respiratory organs Circulatory also absorbs nutrients and disposes wastes

2. Describe gastrovascular cavities. Body wall only 2 cells thick enclose the cavity Dual functions of digestion and distribution Nutrients diffuse through the two layers Example  cnidarians

3. Distinguish between open and closed circulatory systems. Open Blood bathes the internal organs directly No distinction between the blood and interstitial fluid Closed Blood is confined to vessels and is distinct from the interstitial fluid One or more hearts pump blood into large vessels that branch to smaller ones through the organs

4. Describe each of the three components of the cardiovascular system. 1.Heart  atria, ventricles; pumps blood 2.Blood vessels  arteries, veins, capillaries; transport blood 3.Blood  plasma and cells (discussed later)

5. Describe the pulmocutaneous circuit and the systemic circuit, and where these are found. Pulmocutaneous  leads to gas exchange tissues where the blood picks up oxygen Systemic  carries oxygen-rich blood to all body organs and then returns oxygen- poor blood to the right atrium via the veins

6. How does a reptile’s circulation work? Less mixing of oxygen-rich and oxygen- poor blood Have a 3-chambered heart with a single ventricle that is partially divided Have both systemic & pulmonary circuits Pulmonary  conveys blood from heart to the gas-exchange tissues in the lungs and back to the heart

7. Describe the double-circulation system in mammals. 2 atria & 2 ventricles Left side: oxygen-rich blood Right side: oxygen-poor blood  Ensures a vigorous flow of blood to the brain, muscles, and other organs because the blood is pumped a second time after it loses pressure in the capillary beds of the lungs or skin

8. Briefly describe a mammalian heart (include relevant vocabulary). Four chambered heart Atrioventricular valve  between atria & ventricles; prevents backflow Semilunar  2 exits of heart, forced open by pressure Pulse  rhythmic stretching of the arteries caused by the pressure of blood driven by the contractions of the ventricles  heart rate Systole  contraction Diastole  relaxation

9. How is the heart’s rhythmic beat maintained? Certain cells of vertebrate cardiac muscle are self-excitable (contract without a signal from the nervous system) Sinoatrial (SA) node (acts as pacemaker) generates electrical impulses and makes walls contract  signal is relayed to atrioventricular (AV) node which delays and then contracts

10. What are the structural differences in arteries, veins, and capillaries? Artery  thick walls for blood pressure Veins  thinner walls; blood moved by muscle action Both have three layers  1. Outside: elastic fibers to stretch 2. Middle: smooth muscle & elastic 3. Inside: endothelium to minimize resistance of blood flow Capillaries  lack outer 2 layers and facilitates oxygen exchange

11. How is blood flow velocity and blood pressure maintained? The “law of continuity” governs the flow of fluid through the vessels (pipes) The total diameter of vessels is greater in the capillaries, pulling fluid there

12. How does capillary exchange occur? Between blood and interstitial fluid Some substances are carried across an endothelial cell in vesicles (endo- exocytosis) Diffusion is carried down the concentration gradients (ex: oxygen and carbon dioxide)

13. Describe the structure and function of the lymphatic system. Loss of fluids through capillaries is 4 L per day Lost fluid and proteins return to blood via the lymphatic system Enters through lymph capillaries Lymph nodes  filter lymph – honeycomb structure with WBC’s - helps defend the body against infection - maintains volume & protein concentration of blood

14. Describe the components of blood, including plasma and the cellular elements. Plasma  liquid matrix, 90% water, inorganic salts (electrolytes) - pH 7.4 in humans, proteins (fibrinogens to help clotting) - transmits nutrients, metabolic waste, gases, hormones RBC  erythrocytes, 25 trillion in 5 L of blood, lack nuclei, biconcave disc, no mitochondria, carry oxygen - carries 250 million hemoglobin molecules WBC  leukocytes (monocytes, neutrophils, basophils, eosinophils, lymphocytes) - patrol interstitial fluid for pathogens Platelets  fragments of cells, function in blood clotting

15. How are the cellular elements of blood replaced? Destroyed in the liver & spleen RBC’s have a 3-4 month lifespan Pluripotent stem cells  in red marrow of ribs, vertebrae, breastbone, and pelvis - arise in early embryo - way to cure diseases like leukemia

16. Describe the process of blood clotting. Clotting from a self-sealing material Fibrinogen  sealant in inactive form Fibrin  active form, aggregates into threads that form the fabric of the clot - begins with release of clotting factors from platelets with complex chain of reaction Defect  hemophilia; mistake in clotting Thrombus  coagulation within blood vessel 

17. List various cardiovascular diseases and how they can be prevented. 1.Heart attack  prolonged blockage of artery, results in death of cardiac tissue 2.Stroke  blockage of arteries in head, results in death of nervous tissue 3.Atherosclerosis  plaque growth on inner walls of arteries, narrows tunnel 4.Arteriosclerosis  when plaque hardens with calcium deposits, rougher lining encourages clotting within artery, results in blockage 5.Hypertension  high blood pressure (can be inherited) - cholesterol: LDL – bad HDL – good

18. What does gas exchange do? Uptake of molecular oxygen Discharge of carbon dioxide All across the respiratory surface (which must remain moist) Can occur across skin, lungs, or gills (depending on species)

19. Describe the following gas exchange mechanisms: gills, tracheal tubes, lungs 1.Gills  outfoldings of body surface specialized for gas exchange; used in water - [oxygen] is lower, but surface moist 2. Tracheal systems  air tubes that branch throughout the body; gas exchange across moist epithelium 3. Lungs  circulatory system transports oxygen from lungs to the rest of the body – dense net of capillaries lies just under epithelium ex: vertebrates, spiders, terrestrial snails

20. How is breathing regulated? Automatic mechanisms Breathing control centers in the brain: 1. Medulla oblongata 2. Pons Regulates basic breathing rhythm

21. Describe the concept of partial pressure. It is the portion of atmospheric pressure that is contributed by oxygen Gas will always diffuse from higher to lower concentrations

22. Explain oxygen and carbon dioxide transport. Oxygen Carried by respiratory pigments – proteins Hemoglobin  in humans Hemocyanin  protein with copper in arthropods Carbon dioxide Hemoglobin buffers blood and prevents harmful changes in pH from CO 2 Mostly transported in blood as bicarbonate ions

23. Describe the adaptations that deep- diving mammals have for respiration and circulation. Ex: Weddell seal  can dive 200 – 500 meters deep; can stay submerged up to an hour 1.Ability to store oxygen  can store 2x as much in blood and muscles - 2x the volume of blood/kilogram as humans - big spleen – up to 24 L of blood - myoglobin  oxygen-storing protein 2.When they dive  heart rate & oxygen consumption decreases - blood supply is restricted from muscles - derive ATP from anaerobic respiration during dives