Animal Circulation and Animal Circulation and Gas ExchangeGas Exchange

Cardiovascular Cardiovascular SystemSystem

• Heart– atria &

ventricles

• Arteries• Arterioles• Capillaries• Venules• Veins

Evolution of the Vertebrate HeartEvolution 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 HeartEvolution of the Vertebrate Heart• Three chambers (two atria and one ventricle)

– amphibians, reptiles

Evolution of the Vertebrate Evolution of the Vertebrate HeartHeart

• Four chambers (two atria and two ventricles)– Crocodilians,

mammals, birds

Path of Blood Through Path of Blood Through The HeartThe 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 CycleCardiac Cycle

Diastole Atrial Systole

Ventricularr Systole

Contract Neither

Atria Ventricle

Valves AV open Semilunar closed

AV open Semilunar closed

AV closed Semilunar open

Time 0.4 sec 0.1 sec 0.3 sec

Function Fill Heart Overfill Ventricle

Pump Blood

Cardiac OutputCardiac 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 RhythmControl of Heart Rhythm• Sinoatrial node (pacemaker)• Atrioventricular node

Mammalian Blood CompositionMammalian Blood Composition

• Cellular Elements (45%)– Erythrocytes– Leukocytes– Platelets

• Plasma (55%)– Water– Ions– Plasma Proteins– Nutrients– Wastes– Gases– Hormones

Blood ClottingBlood Clotting

• Injury triggers platelets to area• Changes prothrombin to thrombin which than

converts fibrinogen to fibrin

Blood PressureBlood Pressure

• Systolic Pressure• Diastolic Pressure

Cardiovascular DiseaseCardiovascular Disease

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

Cardiovascular “Surgeries”Cardiovascular “Surgeries”

• Angiogram• Angioplasty• Stents

Cardiovascular “Surgeries”Cardiovascular “Surgeries”

• Bypass Surgery

Cardiovascular DiseaseCardiovascular Disease

Cardiovascular DiseaseCardiovascular Disease

Cardiovascular DiseaseCardiovascular Disease

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

Gas Gas ExchangeExchange

Conditions for Respiratory Conditions for Respiratory SurfacesSurfaces

• Large surface area

• Thin

• Moist

Aquatic vs. TerrestrialAquatic 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 SurfacesRespiratory Surfaces

• Cutaneous Respiration

• Gills

• Tracheal Systems

• Lungs

Cutaneous RespirationCutaneous Respiration

• Direct diffusion of gases between the organism and the environment

• Found in Porifera, Cnidarians, Platyhelminthes, nematodes, and some annelids

• Supplements other organisms

GillsGills

• Found in echino-derms, mollusks, annelids, arthropods, some vertebrates

• Countercurrent Gas Exchange

Countercurrent Gas ExchangeCountercurrent Gas Exchange

• Maintains gradient over the whole length of the capillaries

• Extracts 80% of the oxygen from the water

Tracheal SystemsTracheal Systems• Found in arthropods• Tracheae

– open tubes

• Spiracles– openings

• Tracheoles– contact with cells

• Muscle– increase amount of Carbon

Dioxide removed

Tracheal SystemsTracheal Systems

Diffusion LungsDiffusion 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 Ventilation LungsLungs

• Found in amphibians, reptiles, mammals and birds

• Pharynx• Larynx• Trachea• Bronchi• Bronchioles• Alveoli

AlveoliAlveoli

Ventilating The LungsVentilating 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 BreathingNegative Pressure Breathing

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

Breathing Breathing ControlControl

• 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 TransportCarbon 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 MammalsDeep-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 MammalsDeep-diving Mammals• Conservation techniques

– exhale before diving (prevent bends / pressure)

– decrease heartrate and oxygen consumption

– reduce blood supply to muscles (anaerobic)

SmokingSmoking

• 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.