B LOOD The Cardiovascular System. Blood transports substances and maintains homeostasis in the body...
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Transcript of B LOOD The Cardiovascular System. Blood transports substances and maintains homeostasis in the body...
BLOOD AND BLOOD CELLSBlood is a type of CONNECTIVE
TISSUEIt has two basic components:CELLS (rbc, wbc, platelets) =
45%Plasma (water, proteins, amino
acids..etc) = 55%
Hematocrit - volume of blood cells in a sample, should be 45%. The remaining fluid is plasma (55%). To determine the percentages, blood is placed in a centrifuge
Three Types of Blood Cells Red blood cells
(erythrocytes)White blood cells (leukocytes)Platelets (thrombocytes)
Biconcave discs5 million per cubic millimeterLack nucleiHEMATOPOEISIS – formation of
blood cells (bone marrow)Liver & Spleen - phagocytosis
EPO, OR ERYTHROPOIETIN (PRONOUNCED, AH-RITH-RO-POY-TIN), IS A HORMONE PRODUCED BY THE LIVER AND KIDNEYS.
In the first part of a two-night interview broadcast, disgraced cyclist Lance Armstrong admitted to Oprah Winfrey that he took banned substances, including EPO, during all seven of his Tour de France victories.
ERYTHROPOIETIN Erythropoietin (EPO) is a hormone produced
by the kidney that promotes the formation of red blood cells by the bone marrow.
The resultant rise in red cells increases the oxygen-carrying capacity of the blood.
90% erythropoietin is produced by the kidneys 10% erythropoietin is produced by the liver Normal levels of erythropoietin range from 4
up to 24 mU/ml (milliunits per milliliter).
MAIN FUNCTIONS OF RED BLOOD CELLS
Transports oxygen, picks up carbon dioxide
HEMOGLOBIN - molecule that combines with O2
IRON is critical to synthesize hemoglobin
OXYGEN LEVELS Oxyhemoglobin =
plenty of oxygen; bright red Deoxyhemoglobin =
low in O2, “bluish red” The blood on the left is oxygenated, the right
is deoxygenated blood (from a vein)
OXYGENATED DEOXYGENATED
WHITE BLOOD CELLS (LEUKOCYTES)
General function is to protect the body against disease
There are FIVE different kinds of WBCs
Granulocytes (granular cytoplasm)
Neutrophils, Eosinophils, Basophils
Agranulocytes (lacking granular cytoplasm)
Monocytes, Lymphocytes
LYMPHOCYTES Nucleus is dark and takes up almost whole
cell; almost no cytoplasm seen Defense against invaders Yield Antibodies 30% WBC
ERYTHROPOIESIS – DESCRIBES THE PRODUCTION OF RED BLOOD CELLS
The red bone marrow of essentially all bones produces RBCs from birth to about five years of age.
Between the ages of 5 to 20, the long bones slowly lose their ability to produce RBCs.
Above age 20, most RBCs are produced primarily in the marrow of the vertebrae, the sternum, the ribs, and the pelvis.
LIFE CYCLE OF THE RED BLOOD CELL -120 DAYS
1) Kidneys respond to a lower than normal oxygen concentration in the blood by releasing the hormone erythropoietin. 2) Erythropoietin travels to the red bone marrow and stimulates an increase in the production of red blood cells (RBCs). 3) The red bone marrow manufactures RBCs from stem cells that live inside the marrow.
4) RBCs squeeze through blood vessel membranes to enter the circulation. 5) The heart and lungs work to supply continuous movement and oxygenation of RBCs. 6) Damaged or old RBCs are destroyed primarily by the spleen
PLASMA PROTEINS
Albumins – blood pressureGlobulins (alpha, beta, gamma) –
transport lipids and antibodies for immunity
Fibrinogen – important for blood clotting
MAJOR EVENT IN BLOOD CLOTTING =
Fibrinogen converted to FIBRIN
PLASMA The liquid portion of blood is 92% water Also contains nutrients, gases, vitamins (etc)
and plasma proteins
HEMOSTASIS The process of stopping bleeding Involves the coagulation and clotting of the
blood to seal the site of damage
THREE EVENTS IN HEMOSTASIS
1. Blood Vessel Spasm Seratonin = vasoconstrictor 2. Platelet plug formation 3. Blood coagulation - conversion
of fibrinogen to fibrin*Thrombin is an enzyme that causes
the conversion
COAGULATION - THE THICKENING
OF BLOOD TO FORM A CLOT (HEMATOMA)