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 O 2 ► Diffusion between blood and cells ► Bulk flow of CO ► Bulk flow of CO 2

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, insects ► Closed 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.

The Cardiac Cycle ► The rhythmic contraction and relaxation of heart muscles. ► Regulated by auto rhythmic cells which are self- excitable.  SA node, pacemaker ► Upper wall of the right atrium ► Initiates the cycle by contracting both atria  AV node ► Lower half of the right atrium ► Receives a delayed impulse from the SA node then contracts the ventricles.  Systole Phase ► Blood is forced through the pulmonary arteries and aorta and the AV valves are forced to close.

Blood ► RBC, erythrocytes  Transport oxygen ► WBC, leukocytes  Disease fighting cells ► Platelets  Cell fragements  Blood clotting ► Plasma  Liquid

The Excretory System ► The excretory systems help maintain homeostasis in organisms by regulating water balance.

Osmoregulation ► The absorption and excretion of water and dissolved substances so that proper water balance is maintained between the organism and its surroundings.  Marine fish ► Hypoosmotic ► Drink lots, pee little  Fresh water fish ► Hyperosmostic ► Drink little, pee lots

Excretory Mechanisms ► Contractile Vacuoles ► Flame Cells ► Nephridia ► Malpighian tubules ► Kidney