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Circulation

Circulation. Types of circulatory systems. Diffusion – oxygen and carbon dioxide, based on body shape and size Gastrovascular cavities – distribution of substances throughout the body and in digestion. Open circulatory system – arthropods, some molluscs

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Circulation

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  1. Circulation

  2. Types of circulatory systems • Diffusion – oxygen and carbon dioxide, based on body shape and size • Gastrovascular cavities – distribution of substances throughout the body and in digestion. • Open circulatory system – arthropods, some molluscs • Hemolymph, interstitial fluid, clear fluid • Pumped through vessels into sinuses and back to heart • Closed circulatory system – • Blood confined in vessles

  3. Figure 34.3 (b) A closed circulatory system (a) An open circulatory system Blood Heart Heart Interstitial fluid Hemolymph in sinuses Branch vessels in each organ Pores Dorsal vessel (main heart) Tubular heart Ventral vessels Auxiliary hearts

  4. Cardiovascular system • Closed circulatory system of humans • Arteries – blood away from heart • Capillaries – gas exchange, simple squamous tissue • Veins – blood to the heart • Not all arteries carry oxygenated blood and not all veins carry deoxygenated blood • 2 main chambers of the heart • Atrium – receiving chamber • Ventricle – pumping chamber

  5. Figure 34.4 (b) Double circulation: amphibian (c) Double circulation: mammal (a) Single circulation: fish Pulmonary circuit Pulmocutaneous circuit Gill capillaries Lung and skin capillaries Lung capillaries Artery Heart: A A Atrium (A) A A Ventricle (V) V V Left Left Right Right V Vein Systemic capillaries Systemic capillaries Body capillaries Systemic circuit Systemic circuit Key Oxygen-rich blood Oxygen-poor blood

  6. Figure 34.5 7 6 3 3 2 4 1 11 10 5 8 Capillaries of head and forelimbs Superior vena cava Pulmonary artery Pulmonary artery Capillaries of left lung Aorta 9 Capillaries of right lung Pulmonary vein Pulmonary vein Left atrium Right atrium Left ventricle Right ventricle Inferior vena cava Aorta Capillaries of abdominal organs and hind limbs

  7. Figure 34.6 Aorta Pulmonary artery Pulmonary artery Right atrium Left atrium Semilunar valve Semilunar valve Atrioventricular (AV) valve Atrioventricular (AV) valve Right ventricle Left ventricle

  8. The mammalian heart • Approximately the size of a fist • Made of mostly cardiac tissue • Cardiac cycle – one complete sequence of pumping and filling of the heart. • Systole – contraction phase of cardiac cycle • Diastole – relaxation phase of cardiac cycle • Cardiac output – volume of blood each ventricle pumps per minute

  9. Valves • Atrioventricular – separate the atrium from the ventricle • Bicuspid – mitral valve • tricuspid • Semilunar valves – found at exits of the heart • Pulmonary – leaving heart for lungs • Aortic – leaving the heart to the aorta • Lub Dup • Lub – blood against the closed AV valves • Dup – closing of semilunar valves • Murmurs – abnormal sounds

  10. Conduction system • sinoatrial node – pace maker – sets rate and timing of cardiac muscle contraction. • Atrioventricular node – conduct impulses through wall separating atrium and ventricle • ECG – electrocardiogram – graph depicting stages in the cardiac cycle

  11. Figure 34.8-4 1 2 3 4 Signals (yellow) from SA node spread through atria. Signals are delayed at AV node. Bundle branches pass signals to heart apex. Signals spread throughout ventricles. SA node (pacemaker) AV node Bundle branches Purkinje fibers Heart apex ECG

  12. Blood vessels • 3 layers of tissue • Endothelium – think epithelial tissue • Smooth muscle • Durable connective tissue • Artery – arterioles – capillaries – venules - veins • Arteries and veins differ slightly in structure • Arteries have thicker walls due to higher pressure • Veins have valves to prevent backflow

  13. Figure 34.9 Artery Vein LM Red blood cells Valve 100 m Basal lamina Endothelium Endothelium Smooth muscle Smooth muscle Connective tissue Connective tissue Capillary Artery Vein Venule Arteriole 15 m Red blood cell Capillary LM

  14. Blood pressure • Arterial blood pressure is highest during systole (contraction) • Pulse – rhythmic bulging of the artery walls with each heart beat. • Diastole – relaxation phase, arteries go back to normal, lower pressure

  15. Homeostasis • To maintain blood pressure as best it can... • Arterioles will dilate or constrict • Endocrine and nervous system will produce Nitric oxide that will induce vasodilation, regulating blood pressure • Gravity – you will faint to get head level to heart, increasing blood flow to brain • Giraffes have higher systolic pressure, 250mmHg • Lymphatic system – gains liters of fluid (lymph) a day begin lost from capillaries. • Lymph nodes – contain cells that destroy bacteria and viruses.

  16. Figure 34.12 Interstitial fluid Blood capillary Adenoid Tonsils Lymphatic vessels Thymus (immune system) Lymphatic vessel Tissue cells Lymphatic vessel Spleen Lymph nodes Appendix (cecum) Masses of defensive cells Lymph node Peyer’s patches (small intestine)

  17. Blood • 55% plasma – liquid made of water, proteins, wastes, gas • 45% - formed elements • Erythrocytes – red blood cells • Red biconcave disks • No nucleus • Formed in red bone marrow • Leukocytes – white blood cells • Immune system • 5 types • Thrombocytes – platelets • Blood clotting

  18. Figure 34.13 Cellular elements 45% Plasma 55% Number per L (mm3) of blood Functions Cell type Constituent Major functions Leukocytes (white blood cells) Defense and immunity Water 5,000–10,000 Solvent for carrying other substances Separated blood elements Osmotic balance, pH buffering, and regulation of membrane permeability Ions (blood electrolytes) Lymphocytes Basophils Sodium Potassium Calcium Magnesium Chloride Bicarbonate Eosinophils Monocytes Plasma proteins Neutrophils Osmotic balance, pH buffering Albumin Platelets Blood clotting 250,000–400,000 Fibrinogen Clotting Immunoglobulins (antibodies) Defense Erythrocytes (red blood cells) 5,000,000– 6,000,000 Transport of O2 and some CO2 Substances transported by blood Nutrients (such as glucose, fatty acids, vitamins) Waste products of metabolism Respiratory gases (O2 and CO2) Hormones

  19. Cardiovascular disease • Disorders of heart and blood vessels • Cholesterol • Atherosclerosis – hardening of the arteries by fatty deposits heart attack – myocardial infarction – damage or death of cardiac muscle tissue resulting from a blockage of one or more coronary arteries Stroke – death of nervous tissue in the brain due to lack of oxygen. Hypertension – high blood pressure – damages endothelium in arteries, promoting plaque build up

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