sirkulasi.ppt

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies

Circulation and Respiration

Chapter 23

Copyright © McGraw-Hill Companies Permission required for reproduction or display


Outline

• Open vs. Closed Circulation Systems• Vertebrate Circulatory System Functions• Architecture of Vertebrate Circulatory System

Fish Circulation Amphibian and Reptile Circulation Mammalian and Bird Circulation

• Heart Contraction• Cardiovascular Diseases• Respiration


Open and Closed Circulatory Systems

• Cnidarians have cells directly exposed to external environment or to a body cavity (gastrovascular cavity) functioning in digestion and circulation.

• Larger animals transport oxygen and nutrients from the environment and digestive cavity to body cells by internal fluid within a circulatory system.



• Open circulatory system - No distinction between circulating fluid and extracellular fluid of the body tissues (hemolymph).

• Closed circulatory system - Circulating fluid (blood) is always enclosed within vessels that transport blood away from, and back to, a pump (heart).



• Arteries - Carry blood away from the heart.• Veins - Return blood to heart.

Capillaries - Pass blood between arterial and venous system.

• As blood plasma passes through capillaries, pressure forces fluid (interstitial fluid) out capillary walls. Returns to capillaries, and lymph vessels.


Animal Kingdom Circulatory Systems


Vertebrate Circulatory System Functions

• Transportation Respiratory Nutritive Excretory

• Regulation Hormone Transport Temperature Regulation

- Counter-current heat exchange


Vertebrate Circulatory System Functions

• Protection Blood Clotting Immune Defense


Architecture of Vertebrate Circulatory System

• Heart (Pump)• Blood Vessels (Tube network)• Blood (Circulating fluid)

Leaves heart through arteries Passes into arterioles Forced through capillaries Passes to venules Flows to veins Back to heart



• Decrease in blood vessel size causes frictional resistance as fluid passes over walls. Heart must overcome high resistance in

capillary network.



• Arteries Blood comes from heart in large pulses,

thus artery must be able to expand.- Innermost layer composed of endothelial

cells, surrounded by a thick layer of smooth muscle and elastic fibers.

• Arterioles Smaller in diameter than arteries, and

surrounding muscle can be relaxed to enlarge diameter.



• Capillaries Transport oxygen and food from blood to

body’s cells and pick up waste carbon dioxide.

- Thin walls allow gas diffusion.• Veins

Return blood to heart Thin layers of muscles and elastic fibers Unidirectional valves


Blood Vessel Structure


Lymphatic System

• Cardiovascular system is very leaky. Lymphatic system uses second circulatory

system to gather liquid (lymph) .- Returns proteins to circulation.- Transports fats absorbed from intestine.- Aids in body’s defense.


Human Lymphatic System


Blood

• Blood composed of plasma and several types of circulating cells.

• Plasma Components Metabolites and Wastes Salts and Ions Proteins


Blood

• Circulating Cells Erythrocytes (Red blood cells) Carry

hemoglobin, and thus oxygen, to cells. Leukocytes (White blood cells)

- Neutrophils- Macrophages- Lymphocytes

B cells - produce antibodies T cells - attack invading bacteria


Blood

• Platelets Help blood to clot.

- Large cells within bone marrow (megakaryocytes) pinch off bits of cytoplasm.


Fish Circulation

• Fish heart is a four-chambered tube. First two, sinus venosus and atrium are

collection chambers, while second two, ventricle and conus arteriosus are pumping chambers.

Gill respiration delivers fully oxygenated blood to the body, but circulation is sluggish, limiting rate of oxygen delivery.


Heart and Circulation of a Fish


Amphibian and Reptile Circulation

• Advent of lungs resulted in two circulations: Pulmonary circulation - (Lungs) Systematic circulation - (Rest of body)

• Amphibian heart has two two structural features to reduce mixing of oxygenated and deoxygenated blood. Atrium divided into two chambers. Conus arteriosus partially separated by

septum.


Amphibian Heart and Reptile Circulation


Mammalian and Bird Circulation

• Mammals, birds, and crocodiles have four- chambered heart made up of two pumping systems. Oxygenated blood from lungs empties into

left atrium through pulmonary veins.- From atrium, flows into left ventricle.

Ventricle contracts and forces blood out in a single strong pulse.

Mitral valve prevents back-flow.



• Blood within contracting left ventricle moves into aorta. Separated from left ventricle by one - way

aortic valve.• Blood eventually returns to heart.

Superior Vena Cava drains upper body. Inferior Vena Cava drains lower body.



• Right Side Blood passes from right atrium into right

ventricle through one-way tricuspid valve. Passes out contracting ventricle through

pulmonary valve into pulmonary arteries.



Heart Contraction

• Heartbeat originates in sinoatrial (SA) node. Membranes spontaneously depolarize.

- Depolarization passes to ventricles through atrioventricular (AV) node.

Bundle of His Purkinje Fibers


Monitoring Heart’s Performance

• Listen to heart at work If valves are not fully opening or closing,

turbulence is created and can be heard as a heart murmur.

• Measure Blood Pressure Diastolic (Low point) Systolic (High point)

• Measure Depolarization Magnitude of electrical pulse.


Cardiovascular Diseases

• Heart Attacks Blood clot in coronary arteries.

- Angina pectoris• Strokes

Interference with blood flow to brain.• Atherosclerosis

Accumulation of fatty acids, smooth muscle, cholesterol and cellular debris.

- Arteriosclerosis - Calcium deposits.


Respiratory Systems

• Respiration - Uptake of oxygen and simultaneous release of carbon dioxide. Gills (Aquatic organisms) Trachea (Terrestrial arthropods)

- Spiracles Lungs (Terrestrial vertebrates)


Respiration in Aquatic Vertebrates

• A fish swimming continuously pushes water through mouth and out gills. Permits countercurrent flow.


Respiration in Terrestrial Vertebrates

• Amphibians obtain oxygen via lungs and can respire through moist skin.

• Reptiles need more oxygen, but cannot rely on skin. Lungs contain many small air chambers

increasing surface area.



• Mammals have large metabolic oxygen demands due to maintenance of body temperature. Alveoli - Small chambers in lung interior. Bronchiole - Passageways connecting

clusters of aveoli.


Evolution of Vertebrate Lung



• Bird Lungs Flying creates a large oxygen demand,

thus birds possess high lung efficiency.- Air flows into the lungs in one direction.

No dead volume - full oxygenation.- Blood runs in different direction.

Blood leaving lung can still contain more oxygen than exhaled air.


Bird Respiration


Mammalian Respiratory System

• Pair of lungs hang free within thoracic cavity. Bronchus connects each lung to trachea.

- Air enters through nostrils (or mouth), passes into larynx, and then into trachea.

Passes down bronchus to lungs. Thoracic cavity bounded by diaphragm. Each lung covered with pleural membrane. Weight of lung supported in thoracic cavity

by interpleural fluid.


Human Respiratory System


Mechanics of Breathing

• During inhalation, muscular contraction causes walls of chest cavity to expand, so that rib cage moves outward and upward. Diaphragm flattens Internal air pressure decreases

• During exhalation, ribs and diaphragm return to original resting position, forcing air from inner cavity back to atmosphere. Typical tidal volume (0.5) liters of air.


Mechanics of Breathing

• Typical human breath at rest, tidal volume, moves about (0.5) liters of air.

• Lung still contains residual volume of air after breath completed (1200 milliliters). Each exhalation removes approximately

same volume as inhalation added.


Gas Exchange

• Oxygen moves within circulatory system carried piggyback on hemoglobin.

• Hemoglobin uptakes oxygen within red blood cells, and causes diffusion from blood plasma. Carbon dioxide in tissue speeds up

unloading of oxygen.- Bohr Effect


Gas Exchange

• As red blood cells are unloading oxygen, they are also absorbing carbon dioxide from the tissue. To keep carbon dioxide from diffusing out

of red blood cells back into plasma, carbonic anhydrase combines with carbon dioxide and water to form carbonic acid.

• Hemoglobin also has ability to hold and release nitric oxide. Regulates blood pressure and blood flow.



Nature of Lung Cancer

• One of leading causes of death among adults in the world. Most carcinogens are also mutagens.

• Tumor Suppressor Genes Rb protein - acts as brake on cell division. P53 protein - inspects DAN prior to

division.



Smoking Causes Lung Cancer

• Cigarette smoke contains many mutagens: Benzo[a]pyrene binds to three sites on p53

and causes mutations at the inactivation sites.

- Research found p53 gene inactivated in 70% of all lung cancers.

- Nicotine is an addictive drug.


Review

• Open vs. Closed Circulation Systems• Vertebrate Circulatory System Functions• Architecture of Vertebrate Circulatory System

Fish Circulation Amphibian and Reptile Circulation Mammalian and Bird Circulation

• Heart Contraction• Cardiovascular Diseases• Respiration


Copyright © McGraw-Hill Companies Permission required for reproduction or display

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