The document discusses blood, tissue fluid, and lymph. It describes: 1) Blood plasma as a pale yellow liquid consisting mainly of water with dissolved substances and no blood cells. 2) Tissue fluid as similar in composition to blood plasma but with fewer proteins, no blood cells, and varying amounts depending on pressures between blood vessels and tissues. 3) Lymph as collected tissue fluid that is returned to blood vessels through lymphatic vessels, maintaining tissue fluid composition.

1. Blood, Tissue Fluid and
Lymph
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2. Blood plasma
 Pale yellow liquid consisting of a variety of
substances (10%) dissolved in water (90%)
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3. Tissue fluid
 Almost identical in
composition to blood
plasma except fewer
protein molecules, no
red blood cells and
some white blood cell
 The amount depends
on 2 opposing
pressures
– Blood pressure at
arterial end of capillary
– osmosis
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4. Tissue fluid (cont)
 Importance:
– Exchanges of materials between cells and the blood
– Provides optimum environment in which cells can
work
– Homeostasis – maintenance of a constant internal
environment (regulation of glucose concentration,
water, pH, metabolic wastes and temperature)/takes
place to maintain the composition of tissue fluid at a
constant level
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5. Lymph
 10% of tissue fluid are collected and returned to blood
system through lymph vessels and lymphatics
 Lymphatics – tiny, blind-ending vessels with valves (wide
enough to allow large protein molecules to pass
through), found in almost all tissues
 Oedema – build up of tissue fluid due to imbalance of
protein and rate of loss from plasma with concentration
and rate of loss from tissue fluid
 Lymph – fluid inside lymphatics identical to tissue fluid
 Lymph nodes – intervals along lymph vessels which is
involved in protection against disease
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6. Oedema
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7. Lymph (cont)
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8. Largest
lymph vessel
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9. Red blood cells (erythrocytes)
 Red colour caused by the pigment haemoglobin
(globular protein)
 Haemoglobin – transports oxygen from lungs to
respiring tissues
 Formed in bone marrow (liver; humerus, femur;
skull, ribs, pelvis, vertebrae)
 Eventually rupture within some ‘tight spot’ in the
circulatory system, often inside the spleen
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11. Red blood cells (cont)
 The structure is unusual in 3 ways:
i) Red blood cells are very small
(diameter=7μm) – haemoglobin/capillaries
ii) Red blood cells are shaped like a biconcave
disc – surface area to volume ratio
iii) Red blood cells have no nucleus, no
mitochondria and no endoplasmic reticulum –
more haemoglobin
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12. White blood cells (leucocytes)
 Made in bone marrow
 Distinguished from red blood cells:
– White blood cells all have nucleus
– White blood cells are mostly larger (except
lymphocytes)
– White blood cells are either spherical or irregular in
shape
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13. White blood cells
 Phagocytes – cells that destroy invading
microorganisms by phagocytosis (lobed
nuclei and granular cytoplasm)
 Lymphocytes – destroy microorganisms
by secreting chemicals called antibodies
which attach to and destroy the invading
cells (smaller, large round nucleus and
small amount of cytoplasm)
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14. White blood cells
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15. Types of WBCs:
i) granular white blood cells include:
– neutrophils (50 - 70% of WBCs) - phagocytosis (bacteria &
cellular debris); very important in inflammation
– eosinophils (1 - 4%) - help break down blood clots & kill
parasites
– basophils (less than 1%) - synthesize & store histamine (a
substance released during inflammation) & heparin (an
anticoagulant); functions(s) remain unclear
ii) agranular (or non-granular) white blood cells include:
– lymphocytes (25 - 40%) - immune response (including
production of antibodies)
– monocytes (2 - 8%) - phagocytosis (typically as macrophages in
tissues of the liver, spleen, lungs, & lymph nodes)
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17.  Thrombocytes (platelets) - bits of broken up
blood cells that help clot the blood when we cut
ourselves and bleed. When we bleed, platelets,
chemicals and substances called clotting proteins
(prothrombin) help to form an insoluble 'plug' to
seal off the bleeding point.
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18. Some related diseases
 Anemia
 Lymphatic filariasis
 Hemophilia
 AIDS
 Leukemia
 Thalassemia
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19. Haemoglobin
 Oxygen is transported around the body
inside red blood cells in combination with
the protein haemoglobin
 Hb + 4O2 HbO8
haemoglobin oxygen oxyhaemoglobin
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21.  85% CO2 is transported by the blood
through hydrogencarbonate ions, HCO3-,
after dissociation of dissolved CO2
 5% CO2 dissolve in blood plasma without
dissociation
 10% CO2 diffuse into red blood cells,
combining directly with the terminal amine
groups (-NH2) of some of the haemoglobin
molecules (carbamino-haemoglobin)
 When blood reaches lungs, the reactions
go into reverse
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22. The haemoglobin dissociation curve
 Haemoglobin performs the task of picking up
and releasing oxygen very well
 Investigate how haemoglobin behaves:
– Samples extracted from blood and exposed to
different concentrations (partial pressures) of
oxygen
– Amount of oxygen that combines with each sample of
haemoglobin is measured
– Maximum amount of oxygen given a value of 100%
(saturated)
– Amounts at lower oxygen partial pressures are
expressed as a percentage of the maximum value
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23. The percentage saturation of each sample
can be plotted against the partial pressure
of oxygen to obtain the curve
 The shape of the haemoglobin dissociation curve can be
explained by the behaviour of a haemoglobin molecule
as it combines with or loses oxygen molecules
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24. The Bohr shift
 Amount of oxygen that haemoglobin carries is affected
not only by the partial pressure of oxygen, but also by
the partial pressure of carbon dioxide
carbonic anhydrase
 CO2 + H2O H2CO3
carbon dioxide water carbonic acid
 The carbonic acid dissociates:
H2CO3 H+ + HCO3-
carbonic acid hydrogen ion hydrogencarbonate ion
 Haemoglobin readily combines with these hydrogen ions,
forming haemoglobinic acid, HHb (releasing oxygen)
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25.  By removing the hydrogen ions from solution,
haemoglobin helps to maintain the pH of the
blood close to neutral (buffer)
 Bohr effect – the presence of high partial
pressure of carbon dioxide causes haemoglobin
to release oxygen
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26. Fetal haemoglobin
 The partial pressure of oxygen in the
fetus’ blood is only a little lower than that
in its mother’s blood
 Fetal haemoglobin combines more readily
with oxygen than adult haemoglobin
(higher affinity for oxygen)
 Dissociation curve lies above the curve for
adult haemoglobin
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27. Myoglobin
 Red pigment which combines reversibly with oxygen
 Found inside cells in some tissues of the body (muscle
cells)
 Made up of only 1 polypeptide, 1 haem group and can
combine with 1 oxygen molecule
 The oxymyoglobin molecule is very stable and will not
release its oxygen unless partial pressure of oxygen
around it is very low
 Myoglobin has a higher percentage of saturation with
oxygen than haemoglobin
 Acts as an oxygen storage
 The oxygen held by the myoglobin is a reserve, to be
used up only in conditions of particularly great oxygen
demand
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30. High altitude
 At sea level:
– Partial pressure of O2 in atmosphere = 20kPa
– Partial pressure of O2 in an alveolus = 13kPa
– Haemoglobin almost completely saturated with
oxygen
 At 6500m:
– Partial pressure of O2 in atmosphere = 10kPa
– Partial pressure of O2 in an alveolus = 5.3kPa
– Haemoglobin only about 70% saturated in lungs
 Altitude sickness:
– Increase in the rate and depth of breathing
– General feeling of dizziness and weakness (nausea)
– Arterioles in the brains dilate (fluids begins to leak
into brain tissues causing disorientation and into
lungs)
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31. High altitude
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32.  Changes that take place as body
acclimatises:
– Number of red blood cells
increases (40-50% to 50-70%)
 Adaptations to low-oxygen
environments:
– Broad chests (larger lung
capacities)
– Larger hearts (especially right
side that pumps blood to the
lungs)
– More haemoglobin in blood
(increasing efficiency of oxygen
transport) ALBIO9700/2006JK

33. Carbon monoxide
 CO combines with the haem groups in the
haemoglobin molecules forming
carboxyhaemoglobin
 Haemoglobin combines with CO 250 times more
readily than it does with O2
 Carboxyhaemoglobin is a very stable compound
 Low concentrations of CO (0.1%) in the air can
cause death by asphyxiation
 Treatment: administration of a mixture of pure
oxygen and carbon dioxide
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