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بسم الله الرحمن الرحيم. The Blood and B lood Vessels. Dr.Mohammed Sharique Ahmed Quadri Assistant prof. Physiology Al Maarefa College. Objectives . By the end of this lecture you should be able to Describe the composition of Blood
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بسم الله الرحمن الرحيم The Blood and Blood Vessels • Dr.MohammedSharique Ahmed Quadri • Assistant prof. Physiology • Al Maarefa College
Objectives By the end of this lecture you should be able to • Describe the composition of Blood • Describe composition of Plasma and Types of Cells Present [RBC, WBC, Platelets] • List the normal Values for Hb, RBC, WBC, PLT • Define Anemia, Polycythemia, Leukocytosis, Leukopenia, Thrombocytosis, Thrombocytopenia • List the different types of the blood Vessels(Arteries ,Arterioles – resistance, Capillaries, Veins) • Define blood Pressure, Hyper tension, Hypo tension • Define normal Heart rate
BLOOD • Blood transports O2, nutrients to tissues and CO2 to lungs and other products of metabolism to kidneys.
Blood • Represents about 8% of total body weight • Average volume • 5 liters in women • 5.5 liters in men
BLOOD COMPOSITION • Blood consists of • Liquid PLASMA , in which cellular elements are present. • Cellular Elements are • Red Blood Cells(RBC) or Erythrocytes • White Blood Cells (WBC) or Leukocytes • Platelets or Thrombocyte
Normal values • Plasma: fluid part, 55% of total blood volume. • Cellular elements: 45% of total blood volume. • Red Blood Cell [RBC] – 5 millions / mm3 • Hemoglobin [Hb] – 15 gm / dl • White Blood Cell [WBC] – 4000-11000/mm3 • Platelet – 150,000-400,000 /mm3
Blood Composition Hematocrit or packed cell volume: % of total blood volume occupied by RBCs.
Blood • Consists of 3 types of specialized cellular elements suspended in plasma (liquid portion of blood) • Erythrocytes • Red blood cells ( contains hemoglobin) • Important in O2 transport • Leukocytes • White blood cells • Immune system’s mobile defense units • Platelets • Cell fragments • Important in hemostasis(they prevent blood loose from damaged blood vessels).
PLASMA • Plasma is transport medium for inorganic and organic substances. • Plasma Composition: • Water – 90% • Solids – 10 % • Electrolytes [1%]– mainly Na+, Cl-, K+, HCO3-, Ca2+ • Plasma protein [6-8%] • Organic Substances - Glucose, Amino acids, Lipids, Vitamins • Waste products – urea, creatinine • Dissolved gases – O2 and CO2 • Hormones
Plasma • Plasma proteins • Compose 6% to 8% of plasma’s total weight • 3 groups of plasma proteins • Albumins • Most abundant plasma proteins • Globulins • 3 subclasses • Alpha (α) • Beta (β) • Gamma (γ) • Fibrinogen • Key factor in blood clotting • Most of the plasma protein are synthesized in liver.
CLINICAL APPLICATION • Anemia – Decrease in RBC & Hb • Polycythemia– Increase in RBC & Hb • Leukocytosis – Increase in WBC count (more than 11,000 /mm3 • Leukopenia – Decrease in WBC count (less than 4000 /mm3) • Thrombocytosis – Increase in platelet count • Thrombocytopenia – Decrease in platelet count
BLOOD VESSELS • Blood is transported to all parts of the body through blood vessels to supply O2, nutrition and remove the waste products e.g. CO2, Urea. • Oxygenated blood is pumped by left ventricle to Aorta and goes to blood vessels to supply oxygen and nutrition to body. • Blood is returned to right side of the heart as Deoxygenated blood through veins.
Vascular Tree • Consists of • Arteries • Carry blood away from heart to tissues • Arterioles • Smaller branches of arteries • Capillaries • Smaller branches of arterioles • Smallest of vessels across which all exchanges are made with surrounding cells • Venules • Formed when capillaries rejoin • Return blood to heart • Veins • Formed when venules merge • Return blood to heart
Arteries • Specialized to • Take blood from heart to the organs • Has large radius • Large Act as PRESSURE RESERVOIRto provide driving force for blood when heart is relaxing • Has thick, highly elastic wall. • Has elastic fibers in the wall.
Arterioles • Arterioles are highly muscular (smooth muscle). • Have small radius • Have no elastic fiber. • Are Major resistance vessels
Arterioles • Mechanisms involved in adjusting arteriolar resistance • Vasoconstriction • Refers to narrowing of a vessel • Vasodilation • Refers to enlargement in circumference and radius of vessel • Results from relaxation of smooth muscle layer
Capillaries • Thin-walled, small-radius, extensively branched • have endothelial lining only between blood and tissues. • Sites of exchange between blood and surrounding tissue cells (exchange vessels) • Bring blood within reach of every cell. • 10 billions in number.
Veins • Bring blood to heart. • Veins are thin walled as compared to arteries • Large radius • Also serve as blood reservoir • serve as a BLOOD RESERVOIR (under resting conditions nearly 65%of blood in located in the veins). • As they can store blood, they are called they are called ‘CAPACITANCE VESSELS’.
Lymphatic System • Extensive network of one-way vessels • Provides accessory route by which fluid can be returned from interstitial to the blood
Percentage of blood volume in different parts of circulatory system
‘USEFUL INFORMATION’ • Normal Pulse Rate – 72 beats/min (range 60-100 beats/min) • Normal Blood Pressure (BP) – 120/80 mmHg (range for systolic BP – 100-140 mmHg) (range for diastolic BP – 60-90 mmHg) • Hypertension (high blood pressure) – when BP is above 140/90 mmHg. • Hypotension (low blood pressure) – when BP is below 100/60 mmHg.
References • Human physiology by Lauralee Sherwood, seventh edition • Text book physiology by Guyton &Hall,11th edition • Text book of physiology by Linda .s contanzo,third edition