Animal Structure and Function

Animal Structure and Function Thermoregulation Ectotherms Obtain body heat from the environment. Poikilotherms Invertebrates, amphibians, reptiles and fish. cold blooded Endotherms

Generate their own body heat. Homeotherms Mammals Warmblooded Temperature Regulation Cooling evaporation Sweating Panting

Warming by metabolism Shivering Adjusting surface area Changing the volume of blood flow Countercurrent Exchange The Respiratory System Direct

contact with the environment Cells have large surface areas with which they can have exchange with the environment. Gills Evaginated structures that create large surface areas. Tracheae Chitin lined tubes that permeate the body. Oxygen enters the tracheae through opening called spiracles. Lungs

Invaginated structures which allow gas exchange Human Respiration Nose, pharynx, larynx Trachea Bronchi, bronchioles Alveolus Diffusion between alveolar chambers and blood. Bulk flow of O2 Diffusion between blood and cells Bulk flow of CO2

Circulatory System Open Circulatory Systems Blood is pumped into an internal cavity-hemocoel The tissues and organs are bathed in hemolymph. Hemolymph returns to the heart through holes called ostia. Mollusks, Closed

insects Circulatory Systems Blood is confined to vessels. Annelida Octopuses, Squid, Vertebrate Human Circulatory System Basics: Arteries arterioles Capillaries Gas and waste exchange Venules Veins Heart

Pumping Blood Through the Heart Right Atrium Deoxygenated blood enters via the superior vena cava and inferior vena cava Right Ventricle Blood moves through the tricuspid valve (right atrioventricular valve or AV valve) to the right ventricle. Right ventricle pumps the blood to the pulmonary artery through the pulmonary semilunar valve to the lungs.

Left Atrium Oxygenated blood returns to the left Atrium through the pulmonary vein. Left Ventricle Blood moves through the bicuspid (mitral or left AV valve) to the left ventricle. The blood is then pumped from the heart via the aorta through the aortic semilunar valve and to the body.