Respiratory and Circulatory Systems O2 CO2 Lung Breathing, Transport of gases by circulatory system, Capillary Exchange of gases with body cells 1 Breathing Heart Circulatory
system Blood vessels 2 Transport of gases by the circulatory system 3 Exchange of gases with body cells Capillary O2 CO2 Mitochondria Cell
Animals exchange O2 and CO2 across moist body surfaces Cross section of the respiratory surface (the outer skin) CO2 O2 Capillaries Animals exchange O2 and CO2 across moist body surfaces Most animals have specialized body parts that promote gas exchange: gills in most aquatic animals, tracheal systems in insects, and lungs in terrestrial vertebrates. Many animals have adaptations to improve ventilation, the flow of water or air over the
respiratory surface. Gills Body surface Respiratory surface (gills) CO2 O2 Capillary GILL STRUCTURE Water flow Blood vessels
Gill arch Operculum (gill cover) Water flow Gill filaments bearing many platelike lamellae Direction of blood flow through capillaries in lamellae COUNTERCURRENT EXCHANGE Oxygen-rich blood going to body tissues Diffusion of O2 from water to blood
Water flow, showing % O2 100 70 40 15 80 60 30 5
Blood flow in capillary, showing % O2 Oxygen-poor blood coming from the heart Lamella Oxygen-rich water Oxygen-poor water Tracheal Systems Body surface O2 CO2 Respiratory surface
(tips of tracheae) Body cells (no capillaries) NOTE: the circulatory system of insects is not involved in transporting gases Lungs Body surface CO2 CO2 Respiratory surface (within lung) O2 O2
Capillary EVOLUTION CONNECTION: The evolution of lungs facilitated the movement of tetrapods onto land Tetrapods seem to have evolved in shallow water. Fossil fish with legs had lungs and gills. Legs may have helped them lift up to gulp air. The fossil fish Tiktaalik lived about 375 million years ago and illustrates these air-breathing adaptations. Eyes on top of a flat skull Neck Shoulder bones
Fin Human Respiratory System Nasal cavity Left lung Pharynx (Esophagus) Larynx Trachea Right lung Bronchus Bronchiole Diaphragm (Heart) To the From the
heart heart Oxygenrich blood Oxygen-poor blood Bronchiole CO O2 2 Alveoli Blood capillaries Breathing is automatically controlled Brain 1
Nerve signals trigger contraction of the rib muscles and diaphragm. Cerebrospinal fluid 2 Medulla Breathing control center responds to the pH of blood and cerebrospinal fluid. 3 Nerve signals indicate CO2 and O2 levels.
CO2 and O2 sensors in the aorta Heart Diaphragm Rib muscles Circulatory systems facilitate exchange with all body tissues Open circulatory systems are found in all arthropods and most molluscs and consist of a tubular heart, open-ended vessels, and blood that directly bathes the cells and functions as the interstitial fluid. 2015 Pearson Education, Inc. Circulatory systems facilitate exchange with all body tissues
Closed circulatory systems are found in vertebrates, earthworms, squids, and octopuses and consist of a circulatory fluid, blood, that is confined to vessels, keeping blood distinct from the interstitial fluid. 2015 Pearson Education, Inc. EVOLUTION CONNECTION: Vertebrate cardiovascular systems reflect evolution Blood passes through the heart of a fish once in each circuit through the body, an arrangement called single circulation. A single circuit would not supply enough pressure to move blood through the capillaries of the lungs and then to the body capillaries of a terrestrial vertebrate. 2015 Pearson Education, Inc. Fish have 2 chambered hearts
Gill capillaries Heart: Ventricle Atrium Body capillaries 2015 Pearson Education, Inc. EVOLUTION CONNECTION: Vertebrate cardiovascular systems reflect evolution Land vertebrates have a double circulation in which blood is pumped a second time after it loses pressure in the lungs. The pulmonary circuit carries blood between the heart and gas exchange tissues in the lungs. The systemic circuit carries blood between the
heart and the rest of the body. 2015 Pearson Education, Inc. Amphibians and Reptiles have 3 chambered hearts Lung and skin capillaries Pulmocutaneous circuit Atrium Atrium Ventricle Right Left Systemic circuit Systemic
capillaries 2015 Pearson Education, Inc. In the threechambered heart of turtles, snakes, and lizards, the ventricle is partially divided, and less mixing of blood occurs. Birds and Mammals have 4 chambered hearts Lung capillaries Pulmonary circuit Atrium
Atrium Ventricle Ventricle Right Left Systemic circuit Systemic capillaries 2015 Pearson Education, Inc. Capillaries of head, chest, and arms Superior vena cava Pulmonary artery Pulmonary artery
Aorta Pulmonary circuit Systemic circuit Lung capillaries Pulmonary vein Right atrium Inferior vena cava Right ventricle Left
ventricle Left atrium Pulmonary vein Aorta Capillaries of abdominal region and legs 2015 Pearson Education, Inc. Blood flow through the heart- animation Beating Human Heart Video Capillary Epithelium
Smooth muscle Connective tissue Epithelium Basal lamina Epithelium Smooth muscle Connective tissue Artery Vein Arteriole 2015 Pearson Education, Inc.
Valve Venule Capillary Interstitial fluid Tissue cell 2015 Pearson Education, Inc. Diffusion of molecules Plasma (55%) Constituent
Major functions Water Solvent for carrying other substances Ions (blood electrolytes) Sodium Potassium Calcium Magnesium Chloride Bicarbonate Plasma proteins Osmotic balance, pH buffering, and maintaining ion
concentration of interstitial fluid Cell type Centrifuged blood sample Clotting Immunoglobulins (antibodies) Defense Substances transported by blood Nutrients (e.g., glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O2 and CO2) Hormones
Number per L (mm3) of blood Red blood cells (erythrocytes) White blood cells (leukocytes) Osmotic balance and pH buffering Fibrinogen 2015 Pearson Education, Inc. Cellular elements (45%) Basophils
56 million Transport of O2 and some CO2 5,00010,000 Defense and immunity Eosinophils Lymphocytes Monocytes Neutrophils Platelets
Functions 250,000 400,000 Blood clotting p. a. b. o. c. n. d.
m. e. l. f. k. g. j. h. i. 2015 Pearson Education, Inc.
