Transcript Hormone Circulation

Circulation
Bridge to Recovery
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Circulation
• Movement of fluid through an organism
• Circulatory system
– Transport system
– Uses fluid to move substances
No Circulatory Systems
• In simple organisms in moist environments
Open Circulatory Systems
Closed Circulatory Systems
Human Circulatory System
• Heart – muscular pump
• Blood vessels
– Network of tubes
– Closed system
• Blood
Cardiovascular System
• Heart & blood vessels
• Transport functions
– Nutrients
– Wastes
– Oxygen
– Carbon dioxide
• Temperature maintenance
• Hormone circulation
Nutrient & Waste Transport
• Absorbed nutrients to liver for processing
• Liver releases glucose into bloodstream
• Transports amino acid building blocks
• Transfers nitrogenous waste to kidney
Oxygen & Carbon Dioxide
Transport
• Cells require oxygen
• Cells produce carbon dioxide
• Blood carries gasses to & from lungs
Temperature Maintenance
• Heat is constantly produced by cells
• Blood distributes heat
• Brain regulatory center (hypothalamus) maintains
homeostasis
– Surface vessels constrict to conserve heat
– Surface vessels dilate to dissipate heat
Hormone Circulation
• Hormones are chemical messengers
• The circulatory system is the highway
within which hormones travel through
out the body, from their site of production
to the target tissues that are capable of
responding to them.
Blood Circulatory Vessels
• Arteries
• Arterioles
• Capillaries
• Venules
• Veins
Arteries & Arterioles
• Carry blood away from heart
• Aorta leaves heart (largest artery)
• Aorta branches into other arteries
• Arteries branch into arterioles
• Arterioles are smaller in diameter
Walls of Arteries
Capillaries
• Connect arterioles & venules
• One cell thick walls
• Blood cells move through single file
• Site of diffusion of gasses, nutrients,
& wastes
Capillary Beds
• Sphincters regulate blood flow
• Capillaries found throughout tissue
Veins & Venules
• Capillaries empty into venules
• Venules merge into larger veins
• Return blood toward the heart
Valves
• Found in veins
• Prevent backflow of blood
• Varicose veins result from
incompetent valves
Heart
• Pump of the circulatory system
• Human heart has two pumps
• Each side has two chambers
– Atrium above
– Ventricle below
Circulatory Pathways
Heart Valves
• Prevent backflow of blood
• Semilunar valves
– Pulmonary & aortic
– Between ventricle & artery
• Atrioventricular valves
– Between atrium and ventricle
• Right-tricuspid
• Left-bicuspid
Heart Contractions
• Depends on autorhythmic cells in heart
– Sinoatrial node – starts heartbeat (pacemaker)
located in upper wall of right atria
– Atrioventricular node-located at base of rt. atria
– Atrioventricular bundle – in septum, 2 branches
– Purkinje fibers-in ventricular walls
• Cells fire in order
Monitoring Heartbeat
• Heartbeat
– Cycle of contraction & relaxation
• Ways to monitor
– Stethoscope-lubb and dupp sounds
– Monitor blood pressure
• Ventricular diastole – relaxation
• Ventricular systole – contraction
– Electrocardiogram
• P wave-atria contract, ventricles relax
• QRS wave-ventricles contract, atria relax
• T wave-electrical changes that precede ventricular
contraction
Blood Pressure
• Measured in millimeters of mercury
• Normal blood pressure
– Less than 120 over 80
• Hypertension
– High blood pressure
– Over 140 over 90
– Risk of heart attack, stroke, heart failure
• Prehypertension
–
120 to 139 over 80 to 89
Electrocardiogram
Blood
• Plasma
• Cells
• Platelets
Plasma
• Mostly water
• Dissolved substances
– Nutrients, hormones, gases, wastes
– Salts & ions
electrolytes (Ca, Mg, Zn, K) serve
3 functions:
– Proteins-helps balance osmotic pressure
between cells and blood. Examples include
serum albumin, antibodies, fibrinogen, &
prothrombin
Blood Cells & Platelets
• Suspended in plasma
• Types of formed elements
– Red blood cells = erythrocytes
– White blood cells = leukocytes
– Platelets
Platelets
• Cell fragments
• Important for clotting or coagulation
Lymphatic System
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One way circulatory system toward heart
Returns lost fluid to blood
Picks up material from tissue
Cleans material
Lymph Nodes
• Activates immune response
• Cleans lymph
Other Lymphatic Organs
• Spleen
– Destroys old blood cells
– Has emergency blood supply
– Filters blood
• Thymus
– Matures T-cells for immune system
Atherosclerosis
• Thickening & hardening of artery walls
• Accumulation of plaque
• Can block blood, increase pressure
Heart Attack
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Most common cause of death in U.S.
Insufficient blood supply to heart muscle
May be result of blood clot
Warning signs of heart attack
– Tightness in center of chest
– Pain in neck, shoulder or arms
– Lightheadedness, nausea, sweating,
shortness of breath
Angina Pectoris
• Chest pain
• Caused by similar reasons as heart attack
• Reduced blood flow
• Does not kill heart muscle
Stroke
• Interference with blood supply to brain
• Can cause weakness, numbness,
paralysis or Death
End chapter 29