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2 Lecture 11 Outline (Ch. 42) I. Circulatory Systems II.Human Heart III. Blood, Vessels, & Lymph IV.Cardiovascular disorders V.Respiration in different organisms VI.Methods – bulk flow vs. diffusion VII.Gas exchange and partial pressures VIII.Inhalation/exhalation IX.Brain control X.Respiratory problems XI.Preparation for next lecture

3 Circulation carries energy, dissolved gasses, wastes Connects individual cells in distant parts of body Requirements –Blood – fluid for transport –Blood vessels – channels for transport –Heart – pump for circulation Circulation Overview

4 Circulatory systems are open or closed Open- bathes organs in a hemocoel Closed- direct vessel connections to organs Circulation Overview Heart Hemolymph in sinuses surrounding organs Heart Interstitial fluid Small branch vessels In each organ Blood Dorsal vessel (main heart) Auxiliary heartsVentral vessels (b) A closed circulatory system (a) An open circulatory system Tubular heart Pores

5 Vertebrates have a closed circulatory system More efficient –Blood is 5 – 10% of body volume –Flow is more rapid, pressure is higher Multifunctional –Transport dissolved gasses –Distribute nutrients & hormones –Transport waste –Thermoregulation –Circulate immunodefenses Circulation Overview Arteries – away from heart, Veins – toward heart

6 Set of muscular chambers Atria collect blood Ventricles send blood through body The heart has evolved The Vertebrate Heart Atrium empties into ventricle Ventricle pumps blood out of heart  moves to gill capillaries: gas exchange From gills, blood collects and moves to body capillaries  gas exchange From body, blood returns to heart, swimming helps propel blood Single circulation

7 The Vertebrate Heart 2 atria empty into 1 ventricle Ridge or incomplete septum divides ventricle Can shunt blood from lungs to body when under water From body, blood returns to right atrium Double circulation – pulmocutaneous circuit and systemic circuit

8 The Vertebrate Heart 2 atria empty into 2 ventricles Complete septum – right side receives oxygen poor blood from body – sends to lungs Endotherms need to deliver 10X as much dissolved gasses and nutrients/waste as same size ectotherms! Double circulation – pulmonary circuit and systemic circuit

9 4-chambered heart: A closer look 2 pumps Right: deoxygenated blood Left: oxygenated blood Heart

10 Right ventricle pumps deO 2 blood to lungs through pulmonary arteries Pumps into right ventricle Heart Right atrium receives deO 2 blood from veins –Superior vena cava –Inferior vena cava

11 Oxygenated blood returns to left atrium from lungs via pulmonary veins Oxygenated blood pumped to body through aorta Pumps into left ventricle Heart

12 Keeping blood moving Heart valves maintain one- way flow Atrioventricular valves –Between atria & ventricles Semilunar valves –Between ventricles & arteries Heart tricuspid bicuspid/mitral

Which of the following regions contains OXYGENATED blood? 1.Pulmonary arteries 2.Right ventricle 3.Pulmonary veins 4.Superior vena cava 5.Inferior vena cava

14 The Cardiac Cycle Heart

15 The Cardiac Cycle & Blood Pressure Heart Normal blood pressure ~120/70 “Lub-dup” sounds heard with stethoscope –Lub – AV valves closing –Dup – closing of semilunar valves Systolic –Ventricular contractions (higher pressure) Diastolic –Period between contractions (lower pressure) sphygmomanometer

16 Cardiac muscle contracts Present only in the heart Heart Cells linked by intercalated discs Prevents strong contractions from tearing muscle Allows rapid spread of electrical signal for simultaneous regional contraction

17 Keeping blood moving Pacemaker cells initiate and coordinate contractions Sinoatrial (SA) node –Primary pacemaker –Stimulates atrial contractions Atrioventricular (AV) node –Delayed impulse received from SA node –Ventricular contraction after atrial contractions have filled them with blood (delay ~0.1 sec) Heart

18 Plasma Primarily water Dissolved proteins and electrolytes Blood Plasma fluid Cells –Red blood cells – transport –White blood cells – defense –Platelets – clotting

19 Red blood cells: Erythrocytes Most abundant blood cells (over 99%) Transport O 2 and CO 2 Iron-based hemoglobin protein binds to O 2 and transports from areas of high concentration to low concentration Blood

20 Erythrocytes are short-lived Formed in bone marrow Lack nuclei (cannot divide or make proteins) Dead cells are removed by liver and spleen –Iron is recycled, although some is excreted Number of erythrocytes maintained by negative feedback Blood

If an athlete injected erythropoietin (EPO), would this help their performance? 1.No – EPO decreases hemoglobin 2.Yes – EPO increases red blood cell number 3.No – EPO increases blood cell destruction 4.Yes – EPO decreases carbon dioxide levels 5.No – EPO is unrelated to athletic performance

22 White blood cells: leukocytes Less than 1% of blood cells Disease defense –Consume foreign –particles –(macrophages) –Produce antibodies –(lymphocytes) Blood

23 Platelets Cellular fragments aid blood clotting Ruptured cells and platelets work together to produce substances that plug damaged vessels Scabs are platelets embedded in web of fibrin proteins Blood

24 Blood is carried in vessels

25 ArteryVein SEM 100 µm Endothelium Artery Smooth muscle Connective tissue Capillary Basal lamina Endothelium Smooth muscle Connective tissue Valve Vein Arteriole Venule Red blood cell Capillary 15 µm LM

26 Heart ArteriesArterioles CapillariesVenules Veins Carry blood away from heart Thick-walled: Smooth muscle/elastic fibers Withstand high pressure Arteries Blood Vessels

27 Heart ArteriesArterioles CapillariesVenules Veins Control distribution of blood flow Smooth muscle expands / contracts Under hormone / NS control Arterioles Blood Vessels

28 Arterioles Contract walls: redirects blood to heart and muscles when needed (stress, exercise, cold) Relax walls: brings more blood to skin capillaries to dissipate excess heat Precapillary sphincters control blood flow to capillaries Blood Vessels

29 Heart ArteriesArterioles CapillariesVenules Veins Nutrients/waste exchanged with cells: Vessel wall one-cell thick Blood flow very slow Materials exit/enter via diffusion Capillaries Blood Vessels

30 Capillaries connect & exchange Tiny vessels Connect arterioles and venules Interstitial fluid leaks from plasma in capillaries and provides cells with means of exchange Blood Vessels

31 Heart ArteriesArterioles CapillariesVenules Veins Carry blood towards the heart Thin-walled; large diameter One-way to prevent backflow Venules & Veins Blood Vessels

32 Skeletal Muscle Pump: Vein Valve: Blood Vessels

33 Blood Vessels Varicose veins occur if the vein valves become inefficient

What is a correct difference between veins and arteries? 1.Arteries carry blood toward the heart 2.Veins have thicker walls 3.Arteries carry higher pressure blood 4.Veins lack valves 5.Arteries always carry oxygenated blood

35 Cardiovascular Disorders: Leading cause of death in the United States 1) Hypertension = High blood pressure  Resistance in vessels =  work for heart Blood Vessels 2) Atherosclerosis = Deposits (plaques) collect in vessels Connective tissue Smooth muscle Endothelium Plaque (a) Normal artery(b) Partly clogged artery 50 µm 250 µm

36 The lymphatic system Coordinates with circulatory system Includes: lymph nodes, vessels, and glands –Tonsils contain lots of lymphocytes –Thymus matures white blood cells –Spleen filters blood Returns fluid to bloodstream –Lymph capillaries reabsorb interstitial fluid Bodily defense –Contain white blood cells in nodes

37 Lymph Elephantiasis Condition caused by parasitic worm infection of the lymphatic system. Symptoms most common in legs and genitals

38 Lymphatic vessels Narrow, thin- walled Cellular openings act as one-way valves Dead-end in tissues, collect materials flow back to larger blood vessels Lymph

39 If you are an athlete who trains at high elevations, what happens if you compete at a lower elevation? Thought Question:

40 Living things process energy They need oxygen for this - Why? Overview

41 Cellular respiration uses O 2 and produces CO 2 C 6 H 12 O 6 + O 2  CO 2 + H 2 O + ATP energy Breathing – respiration supports this process by exchanging gasses Overview Cell

42 Respiratory systems enable gas exchange Bulk flow –Fluids move in bulk –Air/water move to respiratory surface –Blood moves through vessels Diffusion –Individual molecules move down concentration gradients –Gas exchange across respiratory surface –Gas exchange in tissues Gas Exchange Systems

43 Gills Aquatic gas exchange Gas Exchange Systems Elaborately folded (  surface area) Contain capillary beds Gill size inversely related to [O 2 ] Large gills = low [O 2 ]

44 Gas Exchange Systems Fish Efficiency Dissolved O 2 is < 1% of water (21% of air) Countercurrent exchange increases efficiency

45 Terrestrial respiration Internal –Stay moist & supported Insects have tracheae –Air enters/exits through spiracles –Branching channels (trachioles) allow gas exchange with cells Gas Exchange Systems

46 Vertebrate respiration Terrestrial use of lungs –Evolved from accessory respiratory organs of freshwater fish Amphibians are weird –Remain tied to water –Larval gills to adult lungs –Moist skin transfers gasses Gas Exchange Systems

47 Reptiles & Mammals use lungs exclusively Lack permeable skin Lungs are more efficient –Especially birds! Gas Exchange Systems

48 Human Respiration Air enters through nose and mouth to pharynx Travels through larynx (voice box) Epiglottis directs travel Mammals

49 On to the lungs Trachea  Bronchi  Bronchioles  Alveoli Human Respiration Air is warmed & cleaned Dust & bacteria trapped by mucus Swept up and out by cilia Microscopic chambers provide enormous surface area Surfactant keeps surface moist Association with capillaries –Diffusion of gasses

50 Diffusion Blood arrives from pulmonary artery Low in O 2 –Higher concentration in air diffuses into blood High in CO 2 –Higher concentration in blood diffuses into air Lungs O2O2 CO 2

51 Human Respiration Gas exchange is driven by differences in pressures Blood from body with low O 2, has a partial oxygen pressure (P O2 ) of ~40 mm Hg By contrast, the P O2 in the alveoli is about 100 mm Hg Blood leaving lungs, thus, normally contains a P O2 of ~100 mm

Where is the partial pressure of oxygen lowest? 1.Systemic veins and pulmonary arteries 2.Pulmonary veins and pulmonary arteries 3.Systemic veins and systemic arteries 4.Pulmonary veins and systemic arteries

53 CO 2 Transport CO 2 binds hemoglobin loosely Dissolved in plasma Combines with H 2 0 to form bicarbonate (HCO 3 - ) –More CO 2 = lower pH Transport of gasses The Bohr Effect: Hemoglobin binds more tightly to O 2 when pH is increased and loosely when pH is decreased

54 O 2 Transport Binds to hemoglobin –Removes O 2 from plasma solution –Increases concentration gradient; favors diffusion from air Transport of gasses CO binds more tightly to hemoglobin than O 2 Prevents O 2 transport

Outside lung covered by the visceral pleural membrane Inner wall of thoracic cavity lined with parietal pleural membrane Space between called the pleural cavity –Thin space w fluid –Causes 2 membranes to adhere –Lungs move with thoracic cavity Breathing Mechanisms

56 Breathing Mechanisms Inhalation: Contraction of intercostal muscles expands rib cage Contraction of diaphragm expands the volume of thorax and lungs Thoracic cavity expands, produces negative pressure which draws air into the lungs

Which would increase air intake? 1.relaxing diaphragm and intercostal muscles 2.relaxing diaphragm, contracting intercostal muscles 3.contracting diaphragm and intercostal muscles 4.contracting diaphragm, relaxing intercostal muscles

58 Breathing is involuntary Controlled by respiratory center of the brain Adjusts breath rate & volume based on sensory input –Maintain a constant concentration of CO 2 Breathing Mechanisms

59 Asthma Smooth muscle irritated & constricts or spasms, increased mucus Respiratory Problems Chronic obstructive pulmonary disease (COPD) –Any disorder obstructs airflow on a long-term basis Bronchitis & Pneumonia Inflammations of respiratory passages & lungs Increase in mucus production, decrease in cilia Causes include bacteria, viruses, fungi, & parasites Infection

60 Emphysema Reduces surface area available for gas exchange Labored and difficult breathing 80-90% of deaths linked with smoking Respiratory Problems Alveoli rupture or become brittle creating larger but fewer alveoli

61 Tuberculosis Bacteria attack and cause lesions on lung tissue Respiratory Problems

Things To Do After Lecture 11… Reading and Preparation: 1.Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms. 2.Ch. 42 Self-Quiz: #1, 2, 3, 5, 6, (correct answers in back of book) 3.Read chapter 42, focus on material covered in lecture (terms, concepts, and figures!) 4.Skim next lecture. “HOMEWORK” (NOT COLLECTED – but things to think about for studying): 1.Compare and contrast veins and arteries in terms of structure and function. 2.Diagram the path blood takes from the body, to the heart and lungs, back to the body. 3.Explain in detail how oxygen is carried in the bloodstream and exchanged in the lungs and at cells. 4.Describe at least four diseases/disorders of the respiratory system.