Blood (erythrocytes, leukocytes and platelets)

BLOOD
Prep: Amen Ullah
Lecturer Surgical
12/25/2018 1studyforum911@hotmail.com

Blood
• Blood is a connective tissue
• Its volume is 5-6 L in males
and 4-5 L in females
• It is slightly alkaline, with a pH of ~ 7.4
• Its color varies from bright to dark red
• It has a salty metallic taste
• It is considered as the ‘fluid of life’ because it carries
oxygen from lungs to all parts of the body and carbon
dioxide from all parts of the body to the lungs.
• Also called fluid of growth as will as fluid of health.

PROPERTIES OF BLOOD
1:Color: Blood is red in color.
• Arterial blood: scarlet red because it contains
more oxygen.
• Venous blood: purple red because of more carbon
dioxide.
2. Blood volume
» 70 mL/kg of body weight
» 5 - 6 liters in males
» 4 - 5 liters in females
» newborn baby:450 ml.
• It is about 8% of the body weight in a normal
young healthy adult.

Conti…
3.Temperature - 100.40F
4. pH - 7.35 to 7.45
5. Specific gravity:
• Specific gravity of total blood : 1.052 to 1.061
• Specific gravity blood cells : 1.092 to 1.101
• Specific gravity of plasma : 1.022 to 1.026
6. Viscosity: Blood is five times more viscous than water.
It is mainly due to red blood cells and plasma proteins.

Functions of blood
Blood have four major functions
1. Transportation
2. Regulation
3. Protection
4. Storage

Functions of blood
1. Transportation
• Respiratory
Red blood cells or erythrocytes
transport Oxygen from lungs to
cells and Carbon dioxide from
cells to lungs
• Nutritive
Blood absorb nutrients from
digested foods in GIT and
transport to all the cells in body
• Excretory
Metabolic wastes, excess water and ions , and other molecules not
needed by the body are carried by the blood to the kidneys and
excreted in the urine

Functions of blood
• 2. Regulation
 regulate body temperature
 regulate pH through buffers
 Hormonal
 Enzymes
 Water
 Acid base balance
3. Storage Function :
Water and some important substances like proteins, glucose,
sodium and potassium are constantly required by the tissues.
Blood serves as a readymade source for these substances.
4. Protection
Through hemostasis & immune response.

COMPOSITION OF BLOOD
• Blood contains the blood cells which are called
formed elements and the liquid portion
known as plasma.
• The formed elements or cellular part is 45%.
• The plasma part is 55%

Blood composition

Formed Elements of Blood
• Red blood cells (R.B.C.)
• White blood cells (W.B.C.)
 granular leukocytes
 neutrophils
 eosinophils
 basophils
 agranular leukocytes
 lymphocytes - T cells, B cells, natural killer cells (N.K.C)
 monocytes
• Platelets (special cell fragments)

Major portion of blood
Plasma
• Straw colored clear liquid
• Contains 90% water
• 7% plasma proteins
 created in liver
 confined to bloodstream
 albumin
 maintain blood osmotic
pressure
 immunoglobulins
 antibodies bind to foreign
substances called antigens
 form antigen-antibody
complexes
 fibrinogen
 for clotting
• 2% other substances
 Nutrients, electrolytes, gases,
hormones, waste products
Serum
• clear straw-colored fluid
that oozes from blood clot
• Volume of the serum is
almost the same as that of
plasma (55%).
• Serum = Plasma –Fibrinogen
• Plasma without clotting factors is
called “serum”

Function of plasma proteins
1. Coagulation of blood – Fibrinogen to fibrin
2. Defense mechanism of blood – Immunoglobulins
3. Transport mechanism – α Albumin, β globulin transport hormones, gases,
enzymes, etc.
4. Maintenance of osmotic pressure in blood
5. Acid-base balance
6. Provides viscosity to blood
7. Provides suspension stability of RBC
8. Reserve proteins

• Originate in the bone marrow
• Resemble the shape of a doughnut without a hole (biconcave)
• Average lifespan is 120 days
• Normal value = approximately 4 to 5.5 million per cubic
millimeter of blood
• Contains an iron-rich protein molecule called hemoglobin
• Responsible for carrying oxygen and removing carbon dioxide
from every body cell

Conti…
• Normal hemoglobin level
• Male = 14–18 grams/100 mL of blood
• Female = 12–16 grams/100 mL of blood
• Responsible for carrying oxygen and removing carbon dioxide
from every body cell
• An abnormally low hemoglobin level and/or decrease in the
number of red blood cells is called anemia.
• Symptoms of anemia
1. Weakness
2. Headache
3. Pale skin color
4. Difficulty breathing

• Also known as white blood cells
• Primarily responsible for
destroying foreign substances
such as pathogens
• Appear round and white because they lack hemoglobin
• Normal adult has 4,000 to 11,000 white blood cells per cubic
millimeter of blood
• Types of White Blood Cells
Granulocytes
Agranulocytes

Types of leukocytes

Granulocytes
Neutrophils
Normal value is 1.5 to 8.0 (1,500 to 8,000/mm3).
1. First line of defense against invading micro-organisms.
2. Powerful and effective killer machine – contains
enzymes like protease, elastase, metalloproteinase,
NADPH oxidase; antibody like substances called
defensins.
– Defensins – antimicrobial peptides active against
bacteria and fungi.
• 3.Secrete Platelet Aggregation Factor (PAF) –
accelerates the aggregation of platelet during injury to
the blood vessels

Granulocytes
Eosinophils
Normal levels of eosinophils vary between 0% and 4%, which is under 350
cells per micro-liter of blood.
Secrete lethal substances at the time of exposure to foreign
proteins/parasites
1. Eosinophill peroxidase – detroy worms, bacteria and tumor cells.
2. Major basic protein – damage parasites
3. Eosinophill cationic protein (ECP)- destroys helminths.
4. Eosinophill derived neurotoxin – destroys nerve fibres (myelinated nerve
fibres)

Granulocytes
Basophils
Approximately 0.4% to 1% of white blood cells are basophils.
• Basophill granules release some important substances like –
1. Histamine – Acute hypersensitivity reaction- vascular changes, increase capillary
permeability
2. Heparin – prevents intravascular blood clotting
3. Hyaluronic acid – necessary for deposition of ground substances in basement
membrane
4. Proteases – exaggerate inflammation
• Basophill have IgE receptor – hypersensitivity reaction

Agranulocytes
Monocytes
• Largest in size of all the
white blood cells
• Primary function is
phagocytosis
• Survive for several months
• Effective against chronic
infections
Lymphocytes
• Assist with the immune
system
• Produce antibodies that
destroy pathogens
• Aid in controlling allergic
reactions

Diameter and lifespan of WBCs

(Platelets)
A normal platelet count ranges from 150,000 to 450,000 platelets per
microliter of blood.
Having more than 450,000 platelets is a condition called thrombocytosis.
having less than 150,000 is known as thrombocytopenia.
1. Blood clotting
2. Clot retraction
3. Defense mechanism
4. Homeostasis
5. Repair and rupture
of blood vessel

Hematocrit (Hct) Levels
Hematocrit Value:
This is the ratio of the volume of red cells to the volume
of whole blood
 anticoagulated blood in hematocrit tube centrifuge at
3000rpm for 30 min .
 Blood cell settle down in bottom and plasma remain on
the top .
 45% cellular part and 55% plasma part
 This red blood cells value express in percentage is
called hematocrit value or packed cell volume (PCV)

Thank You

Blood (erythrocytes, leukocytes and platelets)

Blood (erythrocytes, leukocytes and platelets)

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Blood (erythrocytes, leukocytes and platelets)