Animal Circulation and Gas Exchange

Cardiovascular System Heart –atria & ventricles Arteries Arterioles Capillaries Venules Veins

Evolution of the Vertebrate Heart Two chambers (one atria and one ventricle) –along with a sinus venosus and a conus venosus) Two chambers plus septa –lungfish

Evolution of the Vertebrate Heart Three chambers (two atria and one ventricle) –amphibians, reptiles

Evolution of the Vertebrate Heart Four chambers (two atria and two ventricles) –Crocodilians, mammals, birds

Path of Blood Through The Heart Anterior and Posterior Vena Cava Right Atria Atrioventricular (AV) Valve (tricuspid) Right Ventricle Semilunar Valve Pulmonary Arteries Lungs Pulmonary Veins Left Atria Atrioventricular (AV) Valve (bicuspid) Left Ventricle Semilunar Valve Aorta Body

Cardiac Cycle

Cardiac Output Volume of blood per minute from the left ventricle Depends on two factors –Heart rate (pulse) –Stroke volume Average Human –75 ml/beat –70 beats/min –5.25 L/min (your blood volume)

Control of Heart Rhythm Sinoatrial node (pacemaker) Atrioventricular node

Mammalian Blood Composition Cellular Elements (45%) –Erythrocytes –Leukocytes –Platelets Plasma (55%) –Water –Ions –Plasma Proteins –Nutrients –Wastes –Gases –Hormones

Blood Clotting Injury triggers platelets to area Changes prothrombin to thrombin which than converts fibrinogen to fibrin

Blood Pressure Systolic Pressure Diastolic Pressure

Cardiovascular Disease Hypertension Heart Attack Stroke Atherosclerosis Arteriosclerosis LDL’s HDL’s

Cardiovascular “Surgeries” Angiogram Angioplasty Stents

Cardiovascular “Surgeries” Bypass Surgery

Cardiovascular Disease

Hypertension Heart Attack Stroke Atherosclerosis Arteriosclerosis LDL’s HDL’s

Gas Exchange

Conditions for Respiratory Surfaces Large surface area Thin Moist

Aquatic vs. Terrestrial Less than 1% oxygen Oxygen amounts decrease as the temperature increases Aquatic animals use large amounts of energy to obtain oxygen (20%) About 21% oxygen Developed invaginations to increase surface area and decrease evaporation Terrestrial animals may use only 1% - 2% of its energy to obtain oxygen

Respiratory Surfaces Cutaneous Respiration Gills Tracheal Systems Lungs

Cutaneous Respiration Direct diffusion of gases between the organism and the environment Found in Porifera, Cnidarians, Platyhelminthes, nematodes, and some annelids Supplements other organisms

Gills Found in echino- derms, mollusks, annelids, arthropods, some vertebrates Countercurrent Gas Exchange

Maintains gradient over the whole length of the capillaries Extracts 80% of the oxygen from the water

Tracheal Systems Found in arthropods Tracheae –open tubes Spiracles –openings Tracheoles –contact with cells Muscle –increase amount of Carbon Dioxide removed

Tracheal Systems

Diffusion Lungs Found in invertebrates Gas moved primarily by diffusion –may be increased by body movement Modifications –snails - cavity with gill modified into lung –scorpions and spiders - invaginations of the abdomen

Ventilation Lungs Found in amphibians, reptiles, mammals and birds Pharynx Larynx Trachea Bronchi Bronchioles Alveoli

Alveoli

Ventilating The Lungs Positive Pressure Breathing –pushes air down trachea –seen in frogs and other amphibians Negative Pressure Breathing –suction created by diaphragm –seen in mammals

Negative Pressure Breathing

Avian Respiration Airs sacs allow for one-way ventilation Parabronchi rather than alveoli

Breathing Control Occurs in Medulla oblongota and Pons Monitors Carbon Dioxide (converts to carbonic acid) –lowers pH and causes increase in depth and rate of breathing

Carbon Dioxide Transport Carbon dioxide transported from tissue by erythrocyte –7% transported as Carbon Dioxide in blood –23% of Carbon Dioxide and most of the Hydrogen ions are attached to hemoglobin –70% transported as Bicarbonate in plasma

Deep-diving Mammals Stores large amounts of oxygen in blood and muscles (twice as much as us) –twice the volume of blood –huge spleen –myoglobin

Deep-diving Mammals Conservation techniques –exhale before diving (prevent bends / pressure) –decrease heartrate and oxygen consumption –reduce blood supply to muscles (anaerobic)

Smoking In the United States, an estimated 26.2 million men (23.5 percent) and 20.9 million women (18.1 percent) are smokers. These people are at higher risk of heart attack and stroke. Every eight seconds, someone dies from tobacco use. Cigarettes cause more than one in five American deaths.