Ch. 42 Circulation and Gas Exchange. Title: Mar 16 9:17 PM (1 of 59)

Transcription

1 Ch. 42 Circulation and Gas Exchange Title: Mar 16 9:17 PM (1 of 59)

2 Types of circulatory systems 1. Gastrovascular cavities hydra and cnidarians, planarians and flatworms no true circulation, have cavity two cells thick that distributes substances substances easily diffuse through two layers Title: Mar 16 9:19 PM (2 of 59)

3 2. Open and closed circulatory systems adaptation if have many cell layers both have: a. blood circulatory fluid b. blood vessels blood moves through this c. muscular pump heart have blood pressure to blood by pressure gradient Title: Mar 17 10:57 AM (3 of 59)

4 Open circulatory system insects, arthropods, mollusks blood bathes organs directly no difference between blood and interstitial fluid fluid called hemolymph hemolymph pumped into sinuses (spaces) Closed circulatory system earthworms, squids, vertebrates, octopus blood is confined to vessels interstitial fluid and blood are separate Title: Mar 16 9:27 PM (4 of 59)

5 Title: Mar 17 10:56 AM (5 of 59)

6 Cardiovascular system consists of: heart with atria(receive blood) and ventricles (pump out blood) blood vessels arteries, veins, capillaries arteries pump blood away from heart veins bring blood back to heart arteries arterioles capillaries capillary beds capillaries venules veins animals with high metabolic rates usually have a more complex circulatory system Title: Mar 16 9:31 PM (6 of 59)

7 fish two chambered heart (1 atrium, 1 ventricle) amphibians three chambered heart (2 atria, 1 ventricle) double circulation pulmonary and systemic is some mixing of oxygen rich blood with oxygen poor blood reptiles 3 chambered, less mixing of oxy rich and oxy poor blood, have double circulation birds, mammals 4 chambered heart, no mixing of oxy rich and oxy poor blood Title: Mar 16 9:41 PM (7 of 59)

8 2 chambered heart three chambered heart four chambered heart Title: Mar 17 10:59 AM (8 of 59)

9 Flow of blood through mammalian heart Pulmonary circuit 1. right ventricle pumps blood to lungs via pulmonary artery 2. in lungs: blood gets oxygen, gets rid of carbon dioxide 3. blood returns to heart via pulmonary veins 4. blood enters the left atrium 5. blood goes through mitral valve to left ventricle Systemic circuit 6. left venticle pumps blood through aorta 7. blood in aorta goes to body via arteries coronary arteries supply the heart muscle 8. from arteries to capillary beds 9. from capillary beds to veins 10. veins to superior or inferior vena cava (anterior/posterior respectively) 11. from vena cava to right atrium 12. from rigth atrium into right ventricle process starts again Title: Mar 16 9:45 PM (9 of 59)

10 Title: Mar 17 11:01 AM (10 of 59)

11 Title: Mar 17 11:02 AM (11 of 59)

12 Cardiac Cycle= one complete cycle of contracting (pumping) and relaxing (filling) systole = contraction phase diastole = relaxation phase Title: Mar 16 9:53 PM (12 of 59)

13 Cardiac output= volume of blood per minute that the left ventricle pumps into the systemic system cardiac output = heart rate x stroke volume heart rate = number of beats per minute stroke volume = amount of blood pumped during each contraction, ave. = 75 ml four valves in heart: atrioventicular valves between atrium and ventricle semilunar valves between left ventricle and aorta and right ventricle and pulmonary artery Title: Mar 16 9:56 PM (13 of 59)

14 pulse = rhythmic stretching of arteries caused by pressure of blood from contraction of ventricles Heart sounds = "lub dup" heart murmur due to defect in valve, blood goes backwards through valve Title: Mar 16 10:02 PM (14 of 59)

15 Heart can beat without nervous system sinoatrial node (SA node) = pacemaker sets rate and timing of cardiac muscle contractions in wall of right atrium generates electrical impulses that spread through heart walls to atrioventricular node (AV node) in wall between right atrium and ventricle travels through rest of heart muscle measured with ECG or EKG = electrocardiogram Title: Dec 1 3:47 PM (15 of 59)

16 Title: Mar 17 11:04 AM (16 of 59) Control of heart rhythym

17 Structural Differences of Veins and Arteries Title: Mar 16 10:11 PM (17 of 59)

18 Blood flow velocity faster in aorta than capillaries (total cross section) Law of continuity flows faster through narrower tubes than wider tubes (volume per second is constant) Blood pressure hydrostatic pressure= fluid exerting a force on surfaces flows from high conc. to low conc. blood pressure = hydrostatic pressure that blood exerts on vessels peripheral resistance =impedence of blood flow by arterioles total cross sectional area decreases velocity and pressure peripheral resistance Title: Mar 17 11:06 AM (18 of 59)

19 Blood pressure is determined by cardiac output and peripheral resistance (work together) stress increases blood pressure by triggering nervous system and hormonal responses to constrict blood vessels gravity also affects blood pressure, blood needs to go above hea if have long neck like a giraffe, need more pressure blood returns to heart via veins under low pressure skeletal muscles used to push back valves to prevent backflow breathing pressure changes Title: Mar 17 11:31 AM (19 of 59)

20 Valves help blood flow back to heart due to low pressure Title: Mar 17 11:22 AM (20 of 59)

21 To measure blood pressure (mmhg) sphygmomanometer (blood pressure cuff) Title: Mar 17 11:38 AM (21 of 59)

22 blood flow through capillaries is filled to capacity in brain, heart, kidneys, and liver in other capillaries can be partially filled at any one time ex. skin depending on body temperature controlled by smooth muscles if arterioles constrict flow to capillaries decreases also controlled by precapillary sphincter muscles before capillary beds Title: Mar 17 11:41 AM (22 of 59)

23 since capillaries are 1 cell thick, gas exchange between cells and blood happens by diffusion fluid flows out of a capillary at the upstream end near an arteriole, reenters near venule. direction of movement depends on the difference between two opposing forces: blood pressure and osmotic pressure Title: Mar 17 11:46 AM (23 of 59)

24 Lymphatic system function: returns leaky fluid back into blood fluid is called lymph when in lymphatic system flows one way only back to heart (right atrium) also have valves to prevent back flow lymph goes through lymph nodes on the way back lymph nodes filter lymph of viruses, bacteria lymph nodes have white blood cells inside for defense have swollen lymph when have an infection Title: Mar 17 11:50 AM (24 of 59)

25 connective tissue Blood consists of: a. plasma liquid matrix makes up 55% of blood 90% water, inorganic salts (electrolytes),plasma proteins 1. albumin osmotic balance and ph buffer 2. fibrinogen for blood clotting 3. immunoglobulins (antibodies) defense also carries nutrients, waste products, gases, hormones Title: Mar 20 1:58 PM (25 of 59)

26 Title: Nov 29 8:49 AM (26 of 59) components of blood

27 b. Formed elements (45% of blood) 1. erythrocytes (red blood cells) most numerous blood cell, 5 6million/mm3 biconcave disk shaped transport oxygen (oxygen diffuses through RBC membrane) mammalian RBC lack nuclei more room for hemoglobin(iron containing protein that carries oxygen generate ATP via anaerobic metabolism each hemoglobin can bind 4 oxygens RBC about 120 days, get destroyed by phagocytic cells in liver and spleen, can recycle some of the components like iron, amino acids Title: Nov 29 8:50 AM (27 of 59)

28 Title: Nov 29 8:50 AM (28 of 59) Red and White blood cells

29 2. Leukocytes (white blood cells) function is to fight infections spend most of their time in interstitial fluid and lymphatic system neutrophils, monocytes are phagocytes lymphocytes produce immune response basophils discharge histamine (vasodilator) at inflammation sites eosinophils kill parasitic worms, increase during allergy attacks (might phagocytize antigenantibody complexes) 5,000 10,000/mm3 Title: Nov 29 8:51 AM (29 of 59)

30 3. Platelets fragments of cells function in blood clotting Title: Nov 29 8:51 AM (30 of 59)

31 How do RBC, WBC and platelets get made? from pluripotent stem cells in red bone marrow (ribs, sternum, vertebrae and pelvis) stem cells can differentiate into any type of cell Title: Nov 29 8:52 AM (31 of 59)

32 Hematopoiesis process of making RBC negative feedback mechanism based on amount of oxygen in blood kidney converts a plasma protein to erythropoietin erythropoietin stimulates production of RBC if level of oxygen is too high level of erythropoietin is decreased in leukemia cancerous stem cell line cancerous cells crowd out RBC and make WBC, some abnormal 30 pluripotent cells can repopulate bone marrow Title: Nov 29 8:52 AM (32 of 59)

33 Hemotasis process of blood clotting collagen fibers platelets release chemicals that make nearby platelets sticky clotting factors from: platelets Damaged cells Plasma (factors include Ca, Vit K) platelet plug Fibrin Prothrombin Thrombin Fibrinogen Fibrin Title: Nov 29 8:52 AM (33 of 59)

34 Title: Nov 29 8:56 AM (34 of 59) blood clot

35 problems with clotting: a. hemophilia sex linked inherited trait defect in clotting process causes excessive bleeding even with minor cuts and bruises b. thrombus when platelets clump and fibrin coagulates in a blood vessel becomes an embolus if the clot gets loose in blood vessel Title: Nov 29 8:57 AM (35 of 59)

36 Cardiovascular disease diseases of the heart and blood vessels heart attack (myocardial infarction), death of cardiac tissue from blockage of coronary arteries stroke death of nervous tissue due to lack of blood flow or rupture of blood vessel both may result from a thrombus fibrillation when heart beats irregularly use a defibrillizer to bring back rhythm CPR technique used to resuscitate a person who has had a heart attack atherosclerosis impaired arteries due to cardiovascular disease plaques develop(inner wall fills with lipids and fibrous connective tissue) Title: Nov 29 8:57 AM (36 of 59)

37 Atherosclerosis connective tissue smooth muscle endothelium plaque Title: Nov 29 8:57 AM (37 of 59)

38 arteriosclerosis when plaques become hardened by calcium deposits "hardening of the arteries" also lead to thrombus formation increase risk of heart attack or stroke angina pectoris chest pain, means heart is not receiving enough oxygen hypertension (high blood pressure) promotes arteriosclerosis, heart attack and stroke can be controlled by diet, exercise, medication diastolic above 90 = concern Title: Nov 29 8:59 AM (38 of 59)

39 cholesterollow density lipoproteins (LDLs) = bad cholesterol deposits fat in plaques smoking increases LDL high density lipoproteins (HDLs) = good cholesterol can reduce cholesterol deposition exercise increases HDL Title: Nov 29 8:59 AM (39 of 59)

40 Gas Exchange uptake of oxygen from environment and discharge of carbon dioxide to environment respiratory medium = air, 21% gas exchange occurs through respiratory surface by diffusion surfaces are moist so oxygen and carbon dioxide must dissolve in moisture first Title: Nov 29 9:00 AM (40 of 59)

41 Where does it occur? a. protists entire surface of protist b. sponges, cnidarians, flatworms plasma membranes of all cells c. earthworm diffuse through body surface d. fish, marine worms, mollusks, crustaceans gills ventilation increases respiratory medium over surface (makes water move faster over gills, due to low oxygen dissolved in water) countercurrent exchange blood flows in opposite direction of flow of water Title: Nov 29 9:00 AM (41 of 59)

42 Title: Nov 29 9:01 AM (42 of 59) Gill structures

43 Title: Nov 29 9:01 AM (43 of 59) Fish Gills

44 e. tracheal systems advantages: 1. higher conc. of oxygen in air than in water 2. don't have to be ventilated disadvantage: lose water to surrounding environment air tubes= in insects larger insects also use body movement to help when active Title: Nov 29 9:02 AM (44 of 59)

45 lungs lungfishes, spiders, terrestrial snails, vertebrates frogs also use skin for gas exchange turtles use lungs and moist tissue in mouth and anus for gas exchange most reptiles, all birds and mammals use just lungs ectotherm lungs are smaller, less gas exchange area than endotherms Title: Nov 29 9:03 AM (45 of 59)

46 Title: Nov 30 7:06 AM (46 of 59) Mammalian Respiratory System

47 Title: Nov 30 7:07 AM (47 of 59) Alveoli of mouse lung

48 How do we breathe? positive pressure breathing (frog) opens mouth, brings air in nostrils, mouth/nostrils close forcing air to trachea and lungs negative pressure breathing (mammals) works like suction pump, pulling air Title: Nov 30 7:07 AM (48 of 59)

49 tidal volume volume of air an animal inhales and exhales with each breath (500 ml) vital capacity maximum vital capacity during forced breathing ( L) residual volume air left after a forced exhale with lung diseases, residual vol. increases, while vital capacity decreases in birds more complex (have additional air sacs act as bellows) have parabronchi instead of alveoli better gas exchange than mammals, high oxygen exchange Title: Nov 30 7:08 AM (49 of 59)

50 Title: Nov 30 7:08 AM (50 of 59) Bird lungs

51 What causes us to breathe? breathing control centers medulla oblongata and pons medulla monitors level of carbon dioxide in blood due to changes in blood and Cerebral Spinal Fluid ph if oxygen low, sensors in aorta and carotid arteries signal breathing center hyperventilating tricks control center too much CO2 given off so breathing shuts down until CO2 levels increase or oxygen levels decrease Title: Nov 30 7:09 AM (51 of 59)

52 Title: Nov 30 7:09 AM (52 of 59)

53 Pressure gradients also help exchange gases at sea level: partial pressure of oxygen = 160 mm Hg partial pressure of carbon dioxide = 0.23 mm Hg if water is exposed to air, the amount of gas that dissolves in water is proportional to its partial pressure in air and solubility in water gas diffuses from high partial pressure to low partial pressure gas coming into lungs from cells has low oxygen partial pressure, high in air coming into lungs, so diffuses opposite with carbon dioxide Title: Nov 30 7:09 AM (53 of 59)

54 Partial pressure of oxygen is high in lungs, low at cells Partial pressure of carbon dioxide is high in cells and low in lungs Title: Nov 30 7:10 AM (54 of 59)

55 Respiratory pigments also help carry oxygen hemocyanin in arthropods = blue blood, copper carries oxygen hemoglobin iron binds to oxygen four heme subunits with iron in each if one oxygen attaches to iron, other subunits change shape slightly to increase affinity for oxygen (allosteric proteins) Title: Nov 30 7:10 AM (55 of 59)

56 use dissociation curves to show amount of oxygen bound to hemoglobin at particular partial pressures Bohr shift a shift that occurs due to change in ph that will affect hemoglobin's affinity for oxygen Title: Nov 30 7:10 AM (56 of 59)

57 Carbon dioxide Transport 7% in plasma 23% binds to amino groups of hemoglobin 70% in form of bicarbonate ion Title: Nov 30 7:11 AM (57 of 59)

58 Adaptations for deep sea diving Weddell seal can store lots of oxygen in blood and muscles, 5% in lungs and 70% in blood has 2x vol. of blood per kilogram of body weight huge spleen can store 24L of blood myoglobin oxygen storing protein in muscles swim with little muscular effort so don't use oxygen quickly can change depth by increasing or decreasing buoyancy heart rate decreases and oxygen consumption Title: Nov 30 7:11 AM (58 of 59)

59 Title: Nov 30 7:12 AM (59 of 59)