Blood
DR. SAIMA RIZWAN
Learning Outcomes:
By the end of this lecture student will be able to :
► Explain composition of blood
► Analyze functions of blood
► Identify Plasma Proteins & describe their functions
► Explain pathophysiology of Edema
Blood
► Blood is a connective tissue in fluid form
► The average adult has about five liters of blood living
inside of their body, coursing through their vessels,
delivering essential elements, and removing harmful
wastes.
► Without blood, the human body would stop working
COMPOSITION OF BLOOD
8% of body weight, average 5
liters
► 55% Plasma ► 45% Blood
1. 91% water cells
2. 7% plasma proteins ► 99% red blood cells
3. Organic : glucose, amino ► 1% white blood cells
acids, lipids and platelets
4. Inorganic: electrolytes like 2%
sodium, potassium, calcium
etc.
Composition
FUNCTIONS OF BLOOD
1. Transportation:
► Oxygen and Carbon Dioxide: Oxygen from the lungs to the
tissues and transports carbon dioxide from the tissues back to
the lungs for exhalation.
► Nutrients: Glucose, amino acids, fatty acids from the digestive
system to the cells.
► Waste Products: Urea, creatinine to the kidneys and liver for
excretion.
► Hormones: From endocrine glands to target organs.
► Body heat
2. Regulation:
► Body Temperature: By absorbing and distributing heat
throughout the body.
► pH Balance: Acid-base balance (pH) using buffers like
bicarbonate, Hemoglobin etc.
► Fluid Balance: Exchanging water and electrolytes with tissues.
► Blood Pressure
3. Protection:
► Immune Response: White blood cells (leukocytes) in the
blood defend against pathogens (bacteria, viruses, fungi).
► Clotting Mechanism: Platelets and clotting factors in the
blood prevent excessive bleeding by forming clots at the site of
injury.
FUNCTION OF BLOOD CELLS
► RED BLOOD CELLS
1. Carry oxygen lungs to tissues
2. Transport carbon dioxide from tissues to lungs
3. Hemoglobin has a buffering role in maintaining normal pH
FUNCTION OF WHITE BLOOD CELLS
To combat infection by
1. Phagocytosis
2. Antibodies
3. Cell mediated immunity
FUNCTION OF PLATELETS
Blood coagulation
PLASMA PROTEINS
The plasma proteins are:
1. Serum albumin
2. Serum globulin
3. Fibrinogen
Serum contains only albumin and globulin.
The fibrinogen is absent in serum because it is converted into the fibrin
during clotting process.
2. Plasma vs. serum
Plasma is the Serum is the liquid
liquid, cell-free part of blood
part of blood, that AFTER
has been treated coagulation,
with therefore devoid of
anti-coagulants clotting factors as
fibrinogen
Anticoagulated Clotted
serum= plasma - fibrinogen
NORMAL VALUES
The normal values of the plasma proteins are:
► Total proteins : 7.3g/dl (6.4-8.4g/dl)
► Serum albumin : 4.7g/dl
► Serum globulin : 2.3g/dl
► Fibrinogen : 0.3g/dl
Albumin/Globulin
► The ratio between plasma level of albumin
and globulin is called A/G ratio.
► It is an important indicator of some diseases
involving liver or kidney.
► Normal A/G ratio is 2:1.
SEPARATION OF PLASMA
1.
PROTEIN
Precipitation method
2. Salting out method
3. Electrophoretic method
4. Cohn’s fractional precipitation method
5. Ultracentrifugation method
6. Gel filtration chromatography
7. Immunoelectrophoretic method
ORIGIN OF PLASMA PROTEINS
IN EMBRYO
► the plasma proteins are synthesized by the mesenchyme
cells.
IN ADULTS
synthesized in:
1. Reticuloendothelial cells of liver
2. Spleen
3. Bone marrow
4. Disintegrating blood cells
5. General tissue cells
FUNCTIONS OF PLASMA
PROTEINS
1. Role in defense mechanism of body:
❑ The Globulins play an important role in the defense
mechanism of the body by acting as antibodies.
❑ These proteins are also called IMMUNOGLOBULINS.
2. Role in coagulation of blood:
► Fibrinogen -- coagulation of blood
► Fibrinogen is converted into active form called Fibrin
► All the tight fibrin threads are aggregated to form a
meshwork.
3. Role in transport mechanism:
► Albumin, alpha globulin and beta globulin
are responsible for the transport of hormones
enzymes, etc.
► It also plays an important role in transport of
metals in the blood.
Albumin
Globulin (β)
4. ROLE IN MAINTENANCE OF OSMOTIC
PRESSURE IN BLOOD
► At the capillary level, most of the substances are exchanged between the
blood and the tissues.
► Because of their large size the plasma proteins cannot pass through the
capillary membrane easily and remain in the blood.
► In the blood , these proteins exert the colloidal osmotic (oncotic) pressure.
►
► The osmotic pressure exerted by plasma proteins is about 25mm Hg.
5. ROLE IN REGULATION OF ACID-BASE
BALANCE
► Plasma proteins particularly the albumin play an important role in
regulating the acid base balance in the blood.
► Plasma proteins are responsible for 15% of the buffering capacity of
blood.
6. ROLE IN VISCOSITY OF BLOOD
► The plasma proteins provide viscosity to the blood which is
important to maintain the blood pressure
► Albumin provides maximum viscosity than the other plasma
proteins.
7. ROLE IN THE ERYTHROCYTE
SEDIMENTATION RATE
► Globulin and Fibronigen accelerate the tendency of
Rouleaux formation by the red blood cells.
► ESR is mostly influenced by the fibrinogen (coating the
cells and neutralizing their negative charge)
8. ROLE IN THE SUSPENSION STABILITY OF RED
BLOOD CELLS
► During circulation, the red blood cells remain suspended uniformly
in the blood.
► This property of the red blood cells is called the suspension stability.
► Globulin and fibrinogen help in the suspension stability of the red
blood cells (mediate RBC aggregation and blood viscosity)
9. ROLE AS A RESERVE PROTEIN
► During fasting the plasma proteins are utilized by the body tissues
as the last source of energy.
► The plasma proteins are split into amino acids by the tissue
macrophages.
► Because of this the plasma protein are called the reserve protein.
VARIATIONS IN PLASMA PROTEIN
► TOTAL PROTEINS
► INCREASES UNDER FOLLOWING CONDITIONS:
(Hyperproteinemia)
1. Dehydration
2. Hemolysis
3. Acute infections like acute hepatitis and acute nephritis
4. Excess of glucocorticoid
5. Leukemia
6. Rheumatoid arthritis
DECREASES UNDER FOLLOWING CONDITIONS
(Hypoproteinemia)
1. Diarrhea
2. Hemorrhage
3. Burns
4. Pregnancy
5. Malnutrition
6. Prolonged starvation
7. Cirrhosis of liver
8. Chronic infections like chronic hepatitis or chronic
nephritis
ALBUMIN
► INCREASES UNDER FOLLOWING CONDITIONS:
(Hyperproteinemia)
1. Dehydration
2. Excess of glucocorticoid (steroid hormones)
3. Congestive cardiac failure
DECREASES UNDER FOLLOWING CONDITIONS
(Hypoproteinemia)
1. Burns
2. Malnutrition
3. Cirrhosis of liver
4. Hypothyrodism
5. Nephrosis
6. Excessive intake of water
GLOBULIN
► INCREASES UNDER FOLLOWING
CONDITIONS: (Hyperproteinemia)
1. Cirrhosis of liver (defective immunoglobulin
clearance)
2. Chronic infections
3. Nephrosis
4. Rheumatoid arthritis
DECREASES UNDER FOLLOWING CONDITIONS
(Hypoproteinemia)
1. Emphysema
2. Glomerulonephritis
3. Hypogammaglobulinemia
FIBRINOGEN
► INCREASES UNDER FOLLOWING
CONDITIONS: (Hyperproteinemia)
1. Glomerulonephritis
2. Rheumatoid arthritis
3. Acute infections
4. Myocardial infarction
5. Stroke
6. Trauma
RECAP
► Blood composition & function
► Plasma Proteins
► Functions of P proteins
Capillaries and Tissue Fluid Formation
Tissue fluid is constantly being formed and therefore needs to be replaced
Dipping into the tissue fluid there is a network of tiny vessels called lymphatics
whose function is to drain surplus tissue fluid away from the cells
The drained tissue fluid (lymph) Larger lymph vessels transport
is returned to the bloodstream the lymph into the great veins L
and then into the heart y
m
p
Arteriole end Venule end h
of capillary of capillary v
e
s
Capillary s
e
l
Tissue fluid lymphatic
Body
Cells
STARLING FORCES
► Four primary forces:
1. Pc
2. Pif
3. Πc
4. Πif
The sum of these forces …. Net filtration pressure (NTP)
NET FILTRATION RATE
NFP= Pc-Pif-πp+πif
If NFP is positive…… filtration
If NFP is negative….. Absorption
Net Filtration rate = NFP x Kf
Effect of the Different Plasma Proteins on Colloid
Osmotic Pressure
Capillaries and Tissue Fluid Formation
Arteriole end Venule end
of capillary of capillary
Capillary
1.Hydrostatic30mm
2.ICOP 8 mm FILTRATION
3.NIFP -3 mm
Tissue fluid
Body
Cells
Capillaries and Tissue Fluid Formation
Arteriole end
of capillary Venule end
of capillary
Capillary
NET=13mm
PCOP 28 28mm Tissue fluid
Body
Cells
EDEMA
► Imbalance of starling’s forces results in collection of fluid
in the interstitial space, “EDEMA”
► Factors causing edema:
1. ↑cap Kf
2. ↑Pc
3. ↓Πc
4. Impaired lymphatics
Edema
► Two general causes of edema:
1. Abnormal leakage of fluid from the plasma to the interstitial spaces
across the capillaries
2. Failure of the lymphatics to return fluid from the interstitium back into
the blood, often called lymphedema.
The most common clinical cause is excessive capillary fluid filtration.
Any one of the following changes can increase the capillary filtration
rate:
1. Increased capillary filtration coefficient.
2. Increased capillary hydrostatic pressure. cardiac failure.
3. Decreased plasma colloid osmotic pressure. e.g. nephrotic syndrome
and liver failure.
► Pitting edema after pressure
is applied to a small area, the
indentation persists after the
release of the pressure. It can
be caused by systemic
diseases, pregnancy, heart
failure, or local conditions
such as varicose
veins, thrombophlebitis,
insect bites, and dermatitis.
► Non-pitting edema is observed
when the indentation does not
persist. It is associated with such
conditions as lymphedema.
Accumulation of lipidema fat
tissue on legs of 28 year old
woman. The feet are not affected,
the fat can form a cuff of tissue at
the ankles.
