Nature Of Blood PDF

BLOOD Nature of Blood IMPORTANCE OF THE STUDY OF BLOOD As circumstantial or corroborative evidence For disputed parentage – especially for those who are looking for custody of child. Instead of buckle swab use blood for DNA typing. Determination of the cause of death and the length of time...

BLOOD Nature of Blood IMPORTANCE OF THE STUDY OF BLOOD As circumstantial or corroborative evidence For disputed parentage – especially for those who are looking for custody of child. Instead of buckle swab use blood for DNA typing. Determination of the cause of death and the length of time the victim survived the attack – Pool of blood – the victim is possibly alive or survived the attack before died. – No pool of blood – the death of victim is death. Determination of the direction of escape of the victim or the assailant – Blood spatter or Blood patter analysis – how the blood has been spread to know where is the origin of the blood or the position of the victim when the injury was inflicted or how the assailant escaped. – Circle – blood drip – Angle - spat IMPORTANCE OF THE STUDY OF BLOOD Determination of the origin of the flow of blood – Color – Consistency of blood from the crime scene – Examples: Bubbly blood – origin is from lungs. Brownish – blood is coming from stomach due to addition of acid in stomach or the blood is already clotting, the crime is already committed in few ours or few days. Determination of the approximate time the crime was committed – Blood clotting, Color, Or if blood is already solidified, etc. NATURE OF BLOOD 1. Largest circulating tissue of the body – Fluid like – because it contains vital substances 2. Consists of vital substances – Blood cells, Other nutrients, Electrolytes, – The ones being circulated into our cardiovascular system 3. Fluid that circulates in to the Cardiovascular System – Oxygen, nutrients, etc. FUNCTIONS OF BLOOD 1. Transport of: a. Gases (O2 and CO2) b. Nutrients c. Wastes 2. Regulates Body Temperature FUNCTIONS OF BLOOD 3. Regulates pH of the body fluids – Metabolic acidosis – can cause disease in the body such as for elders is arthritis which is too much acidity in the body. 4. Transportation of injected and otherwise given medicine to the affected parts of the body KINDS OF BLOOD 1. Arterial Blood: – Also called as “Capillary Blood” – Bright Red in Color – because it is carrying oxygen. – Oxygenated Blood 2. Venous Blood: – Contains increased amount of CO2 – Dark Red in Color – because it carries CO2 – Non-oxygenated blood CHARACTERISTICS OF BLOOD 1. Color – Bright Red (Arterial Blood) – Dark Red (Venous Blood) 2. Volume – 70% of Total Body Weight – 80-85 mL/kg Body Weight 3. Viscosity – Resistance of blood to flow – Blood is thick and sticky – 4-5 times more viscous than water 4. Specific Gravity – Blood = 1.065 due to cellular elements *Water = 1.000 CHARACTERISTICS OF BLOOD 5. pH Reaction – Slightly Alkaline (pH = 7.35 – 7.45) – lower than 7 – acidic – 7 and above – basic alkaline COMPOSITION OF BLOOD A. Formed Elements (35%) 1. Red Blood Cells (Erythrocytes) Number: 5,000,000 RBCs/mm3 Shape: Disc shape biconcave HEMOGLOBIN (Hb) – Coloring matter of blood – Pigment which is found in the cytoplasm of RBCs – Carries / Transport Oxygen COMPOSITION OF BLOOD 2. White Blood Cells (Leukocytes) Number: 5,000 – 10,000/mm3 Soldiers of the Body a. Agranulocytes – Monocyte – Lymphocytes b. Granulocytes – Eosinophil – Neutrophil – Basophil COMPOSITION OF BLOOD 3. Platelets (Thrombocytes) Number: 150,000 – 350,000/ mm3 Function: Blood Coagulation – Blood clotting COMPOSITION OF BLOOD B. Liquid Portion (65% of total blood volume) 1. Plasma: Straw liquid portion of the blood 2. Serum: Straw-yellowish liquid when blood is allowed to clot For testing such as drugs, etc. Collection, Preservation, Packing and Transportation of Specimens Suspected to Contain Blood Evidence/ Collection Procedure Packing & Storage Sample Put each piece of material in a paper packaging and seal with tape. Blood on If the material is wet or moist, pack each piece of removable Remove the whole object material in a Plastic bag sealed with tape. materials Open and allow to dry on arrival at the police station. Send to the CL in wrapping paper or an envelope. Collect samples by swabbing. Put the swabs in the swab wrapper or a folded piece of Pools of In the case of larger paper. accumulations of blood, take blood several samples from various Package in an envelope, store dry and cool. places. Collection, Preservation, Packing and Transportation of Specimens Suspected to Contain Blood Put the swabs in a swab wrapper or a folded piece of paper. Collect samples using several swabs. Blood in Package in an envelope, store dry and cool. Water Pour the water into a clean, dry test Collect water with a clean pipette tube or a vacuum tube with or syringe. a purple cork. If possible, cut away part of the Put each sample in a paper bag or surrounding material. envelope. Keep dry and cool. If cutting the material is not possible, Put the swabs in the swab wrapper or a Dry blood moisten a swab with sterile/distilled folded piece of paper. water. Package in an envelope, store dry and Rub it until it becomes dark brown/red cool. or until the swab absorbs all the blood. PROBLEMS IN THE STUDY OF BLOOD Where blood has to be searched for. Collection, preservation and transportation of specimen suspected to contain blood. Is the stain that of blood? Does the stain contain blood or another substance? Is it human or animal? If the stain is of human blood, did of come from the victim, the accused or from other persons?