Circulatory System Chapter 42

Slide 2 of 20 Circulation – The basics  3 basic parts  Blood – What type of tissue?  Vessels – tubes for blood movement  Heart – structure that pumps blood  2 Types of systems  Open Circulatory System  Bloods contacts the organs directly  Hemolymph – Combined blood & lymph  Heart pumps hemolymph into sinuses (cavities)  Arthropods & molluscs

Slide 3 of 20 Closed Circulatory System  Blood is contained within vessels & pumped about the body by the heart  Blood is separate from the interstitial fluid  Annelids, cephalopods, & all vertebrates

Slide 4 of 20 Blood Vessels  Arteries – Blood AWAY from the heart  Contain significant amount of smooth muscle  Arterioles – smaller branches of arteries  Capillaries – microscopic vessels  1 cell thickness  Site of diffusion (gas, fluids, etc.)  Veins – carry blood back TO the heart  Valves prevent backflow  Venules – smaller branches of veins

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Slide 7 of 20 Cardiac Cycle Notes  Capillaries are for gas exchange  Arteries  Capillaries  Veins  Cardiac Cycle  Always Atrium  Ventricle  Atria – receive blood from body or lungs  Ventricles – receive blood from atria, pump to body or lungs  Right Atrium  right ventricle  lungs  Lungs  Left Atrium  Left Ventricle  Body  From Body  Veins  Right Atrium

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Slide 9 of 20 Cardiac Cycle  Consists of a systole and diastole  Systole – contraction phase  Diastole – Relaxation phase  Heart Rate – rate of contractions per minute  Stroke volume – amount of blood pumped by the left ventricle during the systole

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Slide 11 of 20 Cardiac Valves  Atrioventricular valves – valve between atria & ventricles  Prevent backflow of blood into atria  Semilunar valves – Exit valves for ventricles  Prevent backflow of blood into ventricles  AV valves close during Ventricular systole  Usually OPEN  Semilunar valves close during Ventricular diastole  Usually CLOSED

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Slide 13 of 20 Electrical Signal Transmission  Sinoatrial (SA) node – Pacemaker of the heart  Located in the upper wall of the right atrium  Sets the rate of cardiac muscle cell contraction  AV node – Delays signals from the SA node  Located in the lower wall of right atrium  Allows atria to completely empty before ventricles contra

Slide 14 of 20 Cardiac (Heart) Rate  Affected by  Sympathetic nerves – accelerate heart rate  Parasympathetic nerves – decelerate heart rate  Body Temperature  Increase Body temp 1°C  10 beats per minute  Fever  increase in pulse rate  Exercise  Rate increase  Hormones  Epinephrine  Increases heart rate

Slide 15 of 20 Systemic Vascular Pressure  Blood pressure  Typically taken at upper arm cuff  Wrist monitors are not used for diagnostic purposes  2 Types of blood pressure are taken  Systolic  Remember from cardiac cycle?  Vascular pressure when heart has contracted  Diastolic  Remember from cardiac cycle?  Vascular pressure when heart is relaxed

Slide 16 of 20 In a typical reading, -- 1 st number is systolic (always larger) -- 2 nd number is diastolic (always smaller) -- Extremely subjective measurement

Slide 17 of 20 Lymphatic System  Returns lost fluid & proteins to the blood  In the form of lymph  Along lymph vessels are lymph nodes  Filter lymph  Part of immune system  attack viruses and bacteria here  Uses White Blood Cells (WBC)

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Slide 19 of 20 Blood  Plasma  Mostly Water  Ions, electrolytes, & plasma proteins  Transports nutrients, gases, wastes, & hormones  Oh yeah, and it carries Blood Cells  Cellular Constituents  Red Blood Cells (RBC or erythrocytes)  Transports oxygen by hemoglobin  White Blood Cells (WBC)  Part of immune system  Platelets  Cellular fragments responsible for blood clotting

Slide 20 of 20 Red Blood Cells (RBCs)  Biconcave discs  Increased surface area enhances O2 transport  250 million molecules of hemoglobin in each RBC  Each hemoglobin = up to 4 O2 molecules  Lack nuclei (more room for hemoglobin)  Lack Mitochondria (so oxygen carried is NOT consumed)

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