Transcript FUNCTIONS OF THE BLOOD

Blood and Plasma
Prof. K. Sivapalan
Blood – introduction.
• Blood is a liquid
tissue.
• It has different types
of cells.
• Intercellular
substance is Plasma.
• There are no tight
junctions, collagen,
and hyaluronic acid.
June 2013
Blood and plasma
2
Composition of the blood.
• Plasma:
– Serum + fibrinogen.
• Cells
– Red blood cells
(erythrocytes)
– White blood cells
(leucocytes).
• Neurtophil, eosinophil,
basophil, monocyte,
lymphocyte.
– Platelets.
June 2013
Blood and plasma
3
Physical properties.
•
•
•
•
Color- red. [hemoglobin]
Osmolality: 290 – 300 m osmol/L.
Osmotic pressure: 5000 mm Hg. [≈7 Atm]
Colloid osmotic pressure [oncotic
pressure] : 25 mm. Hg.
• Viscosity: 3 – 4 times that of water.
• Specific gravity: 1.050 – 1.060.
June 2013
Blood and plasma
4
Functions of Blood
•
•
•
•
Transport of,
Water.
Oxygen.
Nutrients:
• Glucose, amino acids, fatty acids, iron, calcium, etc.
• Wastes:
– Urea, carbon dioxide, bilirubin, heat, acid.
• Hormones:
– Water soluble,
– fat soluble.
June 2013
Blood and plasma
5
FUNCTIONS OF BLOOD-ctd..
• Microcirculation.
• Hemostasis.
– Platelets, fibrinogen and clotting factors.
• Immunity.
– Antibodies, white blood cells.
June 2013
Blood and plasma
6
BLOOD VOLUME.
• Blood : 8 % of the body weight.
• 80 ml / Kg ± 10 %
• Plasma: 5 % of the body weight.
•Males 5-6, females 4-5 liters.
Distribution in the vessels:
Lungs-
20 % [1 Liter.]
Veins-
60 % [3 Liters.]
Heart, Arteries, capillaries:
June 2013
20 % [1 Liter.]
Blood and plasma
7
Distribution in Detail.
Structure.
Aorta
Arteries
Arterioles
Capillaries.
Veins- venules, veins, vena
cave
Heart
Pulmonary vessels
June 2013
Blood and plasma
Percentage
02
08
01
05
54
12
18
8
Measurement.
• Dilution method.
• V1C1 = V2C2.
• Plasma volume.
• Evans blue, Rose Bengal, Vital Red, Radioactive
Iodine etc.
• Blood volume.
– Red Cells labeled with Radio active
Chromium.
June 2013
Blood and plasma
9
Factors that Affect Blood
Volume.
• ECF volumeSodium ions
Dehydration.
Water Balance.
• Blood loss.
June 2013
Blood and plasma
10
Control of Blood Volume.
• Circulatory mechanism
• Volume receptor mechanism.
• Renin - Angiotensin – Aldesterone
mechanism.
• Atrial Natriuretic Peptide.
June 2013
Blood and plasma
11
Circulatory Mechanism
• Blood volume determines cardiac output.
• Cardiac output determines blood pressure.
• Blood pressure determines Urine
production.
• Urine production determines ECF volume
and blood volume.
June 2013
Blood and plasma
12
Volume Receptor Mechanism.
Volume receptors in RA and
IVC.
-
[stimulated by stretch which
represents blood volume]
Decreased
blood volume.
Post. Pituitary through
Hypothalamus.
-[Reabsorption
of water ↓,
↑Urine out put ]
- [ ↓secretion.]
Collecting ducts
in Kidney.
June 2013
+ [ ↑ impulses in
afferents with volume]
Anti Diuretic Hormone.
Blood and plasma
13
Renin - Angiotensin – Aldesterone
Mechanism.
• Renin is secreted by the Juxta Glomerular Cells
in response to low sodium in tubule and low
blood pressure in afferent arterioles.
• It converts angeotensinogen into angeotensin I
which in turn gets converted to angeotensin II.
• Angeotensin stimulates secretion of Aldesteron.
• Aldesteron stimulates sodium re-absorption in
distal tubule.
• Keeps blood volume due to osmotic force.
June 2013
Blood and plasma
14
Atrial Natriuretic Peptide.
• Stretch of the right atrium is determined by
venus return which mainly depends on
blood volume.
• ANP is secreted by Right Atrium in
response to stretch.
• ANP causes Sodium and water loss in
urine.
June 2013
Blood and plasma
15
Properties of plasma.
•
•
•
•
•
•
Straw color.
Volume - 3.5 liters.
High Viscosity.
Osmolality- 290 m Osmols/L
Specific gravity- 1.025.
Coagulability.
June 2013
Blood and plasma
16
Composition of PLASMA.
• Proteins- 7.5 g/100 ml. (dL)
–
–
–
–
•
•
•
•
Albumin.
4.5 g.
Globulin.
2.5 g.
Fibrinogen.
0.3 g.
[source: liver, plasma cells.]
Electrolytes.
Nutrients.
Hormones.
Waste products.
June 2013
Blood and plasma
17
Functions of plasma.
•
•
•
•
•
•
Fluid exchange.
Maintenance of pH- Buffering.
Transport of substances.
Hemostasis- Clotting.
Immunity.
Reserve of body proteins.
June 2013
Blood and plasma
18
MEASUREMENT OF VISCOSITY.
• Erythrocyte
Sedimentation Rate.
• Height of clear plasma at
the end of the first hour of
standing.
• Determinants of ESR:
– VISCOSITY of plasma.
– ROULEAUX formation.
• Westegran tube in ESR
stand.
• VISCOMETER.
June 2013
Blood and plasma
19