How does a feathery fringe help this animal survive? Figure 42.1 How does a feathery fringe help this animal survive?

Internal transport in gastrovascular cavities Circular canal Mouth Pharynx Mouth Radial canal 5 cm 2 mm Figure 42.2 Internal transport in gastrovascular cavities (a) The moon jelly Aurelia, a cnidarian (b) The planarian Dugesia, a flatworm

Open and closed circulatory systems Heart Heart Blood Hemolymph in sinuses surrounding organs Interstitial fluid Small branch vessels In each organ Pores Dorsal vessel (main heart) Figure 42.3 Open and closed circulatory systems Tubular heart Auxiliary hearts Ventral vessels (a) An open circulatory system (b) A closed circulatory system

Single circulation in fishes Gill capillaries Artery Gill circulation Ventricle Heart Atrium Figure 42.4 Single circulation in fishes Systemic circulation Vein Systemic capillaries

Double circulation in vertebrates Mammals and Birds Amphibians Reptiles Lung and skin capillaries Lung capillaries Lung capillaries Right systemic aorta Pulmocutaneous circuit Pulmonary circuit Pulmonary circuit Atrium (A) Atrium (A) A A A A Ventricle (V) V V Left systemic aorta V V Right Left Right Left Right Left Systemic circuit Systemic circuit Figure 42.5 Double circulation in vertebrates Systemic capillaries Systemic capillaries Systemic capillaries

mammalian cardiovascular system Superior vena cava Returns deoxygenated blood from body to heart RA Capillaries of head and Forelimbs - EXCHANGE 7 Pulmonary artery Pulmonary artery Carries deoxygenated blood to lungs Capillaries of right Lung GAS EXCHANGE Aorta 9 Capillaries of left Lung GAS EXCHANGE 3 2 3 4 11 Pulmonary vein Carries oxygenated blood to heart: LA Pulmonary vein 5 1 Right Atrium RA - Receives deoxygenated blood from body Left Atrium - LA Receives oxygenated blood from lungs 10 Figure 42.6 The mammalian cardiovascular system: an overview Right Ventricle RV - Pumps blood to lungs Left Ventricle - LV Pumps oxygenated blood to body Inferior vena cava Returns deoxygenated blood from body to heart RA Aorta = main artery to body for Systemic Circulation mammalian cardiovascular system Capillaries of abdominal organs and hind limbs EXCHANGE with body cells 8

Mammalian Heart Pulmonary artery - to lungs Aorta - systemic circulation Right Atrium RA Receives Deoxygented Blood from body Pulmonary veins - from lungs to heart Left Atrium LA Receives oxgenated blood from lungs Semilunar valve Semilunar valve Figure 42.7 The mammalian heart: a closer look Atrioventricular valve Atrioventricular valve Right Ventricle RV Pumps to lungs for gas exchange Left Ventricle LV Pumps oxygenated blood to body via aorta

Cardiac cycle 2 Atrial systole; ventricular diastole Semilunar valves closed 0.1 sec Semilunar valves open AV valves open 0.4 sec 0.3 sec Figure 42.8 The cardiac cycle 1 Atrial and ventricular diastole AV valves closed 3 Ventricular systole; atrial diastole

Control of heart rhythm 1 Pacemaker generates wave of signals to contract. 2 Signals are delayed at AV node. 3 Signals pass to heart apex. 4 Signals spread throughout ventricles. AV node SA node (pacemaker) Bundle branches Purkinje Fibers: ventricles contract Figure 42.9 The control of heart rhythm Heart apex ECG

Structure of blood vessels Artery Vein SEM 100 µm Valve Basal lamina Endothelium Endothelium Smooth muscle Smooth muscle Connective tissue Connective tissue Capillary Artery Vein Figure 42.10 The structure of blood vessels Arteriole Venule 15 µm Red blood cell Capillary LM

The interrelationship of cross-sectional area of blood vessels, blood flow velocity, and blood pressure. 5,000 4,000 Area (cm2) 3,000 2,000 1,000 50 40 Velocity (cm/sec) 30 20 10 Figure 42.11 The interrelationship of cross-sectional area of blood vessels, blood flow velocity, and blood pressure 120 Systolic pressure 100 Pressure (mm Hg) 80 60 Diastolic pressure 40 20 Aorta Veins Arteries Arterioles Venules Capillaries Venae cavae

Question: How do endothelial cells control vasoconstriction? RESULTS Ser Leu Endothelin Ser Met Cys Ser Cys —NH3+ Asp Lys Glu Cys Val Tyr Phe Cys His Leu Asp Ile Ile Trp —COO– Cys Trp Figure 42.12 How do endothelial cells control vasoconstriction? Parent polypeptide 53 73 1 203 Endothelin

Measurement of blood pressure: sphygmomanometer Blood pressure reading: 120/70 Pressure in cuff greater than 120 mm Hg Pressure in cuff drops below 120 mm Hg Pressure in cuff below 70 mm Hg Rubber cuff inflated with air 120 120 70 Figure 42.13 Measurement of blood pressure Artery closed Sounds audible in stethoscope Sounds stop

Blood flow in veins Valve (closed) Direction of blood flow in vein (toward heart) Valve (open) Skeletal muscle Figure 42.14 Blood flow in veins Valve (closed)

Blood flow in capillary beds Precapillary sphincters Thoroughfare channel Capillaries Arteriole Venule (a) Sphincters relaxed Figure 42.15 Blood flow in capillary beds Arteriole Venule (b) Sphincters contracted

Fluid exchange between capillaries and the interstitial fluid Body tissue INTERSTITIAL FLUID Capillary Net fluid movement out Net fluid movement in Direction of blood flow Blood pressure = hydrostatic pressure Figure 42.16 Fluid exchange between capillaries and the interstitial fluid Inward flow Pressure Outward flow Osmotic pressure Arterial end of capillary Venous end

Composition of mammalian blood Plasma 55% Constituent Major functions Cellular elements 45% Cell type Number per µL (mm3) of blood Functions Water Solvent for carrying other substances Erythrocytes (red blood cells) 5–6 million Transport oxygen and help transport carbon dioxide Ions (blood electrolytes) Sodium Potassium Calcium Magnesium Chloride Bicarbonate Osmotic balance, pH buffering, and regulation of membrane permeability Separated blood elements Leukocytes (white blood cells) 5,000–10,000 Defense and immunity Plasma proteins Albumin Osmotic balance pH buffering Lymphocyte Basophil Fibrinogen Figure 42.17 The composition of mammalian blood For the Discovery Video Blood, go to Animation and Video Files. For the Cell Biology Video Leukocyte Adhesion and Rolling, go to Animation and Video Files. Clotting Immunoglobulins (antibodies) Defense Eosinophil Neutrophil Monocyte Substances transported by blood Nutrients (such as glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O2 and CO2) Hormones Platelets 250,000– 400,000 Blood clotting

Blood clotting Platelet plug Fibrin clot Platelet releases chemicals Red blood cell Collagen fibers Platelet plug Fibrin clot Platelet releases chemicals that make nearby platelets sticky Clotting factors from: Platelets Damaged cells Plasma (factors include calcium, vitamin K) Figure 42.18 Blood clotting Prothrombin Thrombin Fibrinogen Fibrin 5 µm

Differentiation of Blood Cells Stem cells in bone marrow Lymphoid stem cells Myeloid stem cells Lymphocytes B cells T cells Figure 42.19 Differentiation of blood cells Erythrocytes Neutrophils Platelets Eosinophils Monocytes Basophils

Atherosclerosis Plaque Connective tissue Smooth muscle Endothelium Figure 42.20 Atherosclerosis (a) Normal artery 50 µm (b) Partly clogged artery 250 µm

Gills are outfoldings of the body that create a large surface area for gas exchange Coelom Gills Figure 42.21 Diversity in the structure of gills, external body surfaces that function in gas exchange Gills Tube foot Parapodium (functions as gill) (a) Marine worm (b) Crayfish (c) Sea star

Structure and function of fish gills Fluid flow through gill filament Oxygen-poor blood Anatomy of gills Oxygen-rich blood Gill arch Lamella Gill arch Gill filament organization Blood vessels Water flow Operculum Water flow between lamellae Blood flow through capillaries in lamella Countercurrent exchange Figure 42.22 The structure and function of fish gills PO2 (mm Hg) in water 150 120 90 60 30 Gill filaments Net diffusion of O2from water to blood 140 110 80 50 20 PO2 (mm Hg) in blood

Tracheal systems Tracheae = air tubes Air sac Trachea Air sacs External opening: spiracles Tracheoles Mitochondria Muscle fiber Body cell Air sac Tracheole Figure 42.23 Tracheal systems Trachea Air external openings spiracles Body wall 2.5 µm

Mammalian Respiratory System Branch of pulmonary vein (oxygen-rich blood) Branch of pulmonary artery (oxygen-poor blood) Terminal bronchiole Nasal cavity Pharynx Larynx Alveoli (Esophagus) Left lung Trachea Right lung Figure 42.24 The mammalian respiratory system Bronchus Bronchiole Diaphragm Heart SEM Colorized SEM 50 µm 50 µm

Negative pressure breathing: H --> L Rib cage expands as rib muscles contract Rib cage gets smaller as rib muscles relax Air inhaled Air exhaled Lung Figure 42.25 Negative pressure breathing Diaphragm INHALATION Diaphragm contracts (moves down) Volume increases Pressure decreases Air rushes in EXHALATION Diaphragm relaxes (moves up) Volume decreases Pressure increases Air rushes out

The Avian Respiratory System Air Air Anterior air sacs Trachea Posterior air sacs Lungs Lungs Air tubes (parabronchi) in lung Figure 42.26 The avian respiratory system 1 mm INHALATION Air sacs fill EXHALATION Air sacs empty; Lungs Fill

Automatic control of breathing Cerebrospinal fluid Pons Breathing control centers Medulla oblongata Carotid arteries Figure 42.27 Automatic control of breathing Aorta Diaphragm Rib muscles

Loading and unloading of respiratory gases Alveolus Alveolus PO2 = 100 mm Hg PCO2 = 40 mm Hg PO2 = 40 PO2 = 100 PCO2 = 46 PCO2 = 40 Circulatory system Circulatory system PO2 = 40 Figure 42.28 Loading and unloading of respiratory gases PO2 = 100 PCO2 = 46 PCO2 = 40 PO2 ≤ 40 mm Hg PCO2 ≥ 46 mm Hg Body tissue Body tissue (a) Oxygen (b) Carbon dioxide

 Chains Iron Heme  Chains Hemoglobin

Dissociation curves for hemoglobin at 37ºC 100 O2 unloaded to tissues at rest 80 O2 unloaded to tissues during exercise 60 O2 saturation of hemoglobin (%) 40 20 20 40 60 80 100 Tissues during exercise Tissues at rest Lungs PO2 (mm Hg) (a) PO2 and hemoglobin dissociation at pH 7.4 100 pH 7.4 80 pH 7.2 Figure 42.29 Dissociation curves for hemoglobin at 37ºC Hemoglobin retains less O2 at lower pH (higher CO2 concentration) 60 O2 saturation of hemoglobin (%) 40 20 20 40 60 80 100 PO2 (mm Hg) (b) pH and hemoglobin dissociation

Carbon dioxide transport in the blood Body tissue CO2 produced CO2 transport from tissues Interstitial fluid CO2 Plasma within capillary CO2 Capillary wall CO2 H2O Red blood cell Hemoglobin picks up CO2 and H+ H2CO3 Hb Carbonic acid HCO3– Bicarbonate + H+ HCO3– To lungs CO2 transport to lungs HCO3– HCO3– + H+ Figure 42.30 Carbon dioxide transport in the blood Hemoglobin releases CO2 and H+ H2CO3 Hb H2O CO2 CO2 CO2 CO2 Alveolar space in lung

Review Inhaled air Exhaled air Lungs - Alveolar Air Spaces GAS EXCHANGE Alveolar epithelial cells CO2 O2 CO2 O2 Pulmonary arteries Alveolar capillaries of lung Pulmonary veins Systemic veins Systemic arteries Heart Systemic capillaries CO2 O2 CO2 O2 Body tissue - GAS EXCHANGE

You should now be able to: Compare and contrast open and closed circulatory systems. Compare and contrast the circulatory systems of fish, amphibians, reptiles, and mammals or birds. Distinguish between pulmonary and systemic circuits and explain the function of each. Trace the path of a red blood cell through the human heart, pulmonary circuit, and systemic circuit.

Define cardiac cycle and explain the role of the sinoatrial node. Relate the structures of capillaries, arteries, and veins to their function. Define blood pressure and cardiac output and describe two factors that influence each. Explain how osmotic pressure and hydrostatic pressure regulate the exchange of fluid and solutes across the capillary walls.

Describe the role played by the lymphatic system in relation to the circulatory system. Describe the function of erythrocytes, leukocytes, platelets, fibrin. Distinguish between a heart attack and stroke. Discuss the advantages and disadvantages of water and of air as respiratory media.

For humans, describe the exchange of gases in the lungs and in tissues. Draw and explain the hemoglobin-oxygen dissociation curve.