Transcript Life & Times of RBC (powerpoint)

The Life & Times of RBC
Birthplace
 Blood cells are produced in the in the red bone marrow
(tissues within the ends of the bone that replaces and
produces the red blood cells and is also the
manufacturing site of white blood cells) of the interior of
bones.
Source: http://www.healthcare.ucla.edu/transplant/images/bonemarrowtransplant_1.jpg
Components of Blood
 Blood is made of cells and proteins.
 Fluid Fraction: Plasma (55% of blood volume)
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Over 90% is water.
60 proteins are present in blood. The most important are:
 albumin, which is involved in osmotic balance;
 globulins, involved in immune response;
 fibrinogen, which is responsible for blood clotting.
 Cellular Fraction (45% of blood volume)
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Consists of red blood cells, white blood cells & platelets.
 Red blood cells make up 99% of all blood cells.
 The remaining cells are white blood cells and blood
platelets.
Blood Cell Family
 red blood cells (erythrocytes)
 white blood cells (leukocytes)
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lymphocytes
neutrophils
basophils
monocytes
 platelets
Red Blood Cells (Erythrocytes)
 These cells number in the trillions and are the greatest
number of blood cells in the body.
 Produced mainly in the red bone marrow, but are also
produced in the liver & spleen.
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As they die, the red marrow replaces them in enormous
numbers at a rate of about a million a minute.
 The main function of is to transport O2 (oxygen).
 To create as much space as possible for hemoglobin,
the cell nucleus disappears as the cell matures,
changing their name to red corpuscles or erythrocytes.
 Because they have no nucleus, their life span is
decreased to about 120 days (four months).
Hemoglobin
 Hemoglobin is a complex iron protein substance.
 It is the component of red blood cells which gives red
blood cells their special oxygen carrying proficiency as
well as their colour.
 Although other substances in the body such as water
and plasma can also carry oxygen, hemoglobin is
unique in its oxygen carrying capacity because it
increases by more than 50 times the quantity of oxygen
it can carry.
White Blood Cells (Leukocytes)
 These cells are diverse in shapes and sizes, they are
larger in size and rounder than the red blood cells, but
fewer in number (a ratio of about 1:700).
 Leukocytes or white corpuscles are developed in bone
marrow, the replacement of white blood cells can take
place in a number of locations in the body: in the lymph
nodes, in the intestinal tract , and in the spleen.
 They do have nuclei.
 They have three main functions:
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response to tissue damage and help with its repair;
defense of the body against foreign organisms; and
scavenging dead cell debris.
 Pus is the remaining protein fragments of neutralized
foreign bacteria and dead white cells after the immune
battle has taken place.
Specific WBC & Their Functions
 T- & B-Lymphocytes
 20-40% of all leukocytes are T- and B-lymphocytes.
 Their function is to mount an immune response in the face of
infection, they are the grunts.
 Neutrophils
 Neutrophils are small, very mobile cells, they travel across the
epithelial layer and enter the tissues.
 Neutrophils devour pathogens by phagocytosis, they are the rangers.
 Basophils
 Basophils are involved in blood clotting, but they also contain
enzymes to destroy invading bacteria, they are the engineer corps.
 Monocytes
 When stimulated, monocytes transform into macrophages.
 Macrophages are the heavy cavalry of the defense mechanism; they
phagocytize most of the pathogens, they are the tanks.
Platelets (Thrombocytes)
 Platelets are not even cells, they are parts of cells,
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chunks of cytoplasm surrounded by plasma
membranes.
Platelets lack nuclei and are one fourth of the size of
red blood cells.
They are a crucial part of the blood clotting mechanism
Platelets travel with the blood and assist to prevent the
organism from bleeding to death if it experiences even
the smallest of wounds.
They activates some of the first biochemical processes
needed to clot blood.
The change of blood from a fluid to a solid is called
clotting .
Blood Groups
 The ABO blood group was the first blood group system
discovered, by Landsteiner at the beginning of this
century.
 Based on 2 antigens (agglutinogens): A & B.
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genetically coded for
found on the surface of the cell membrane
 You have the antibodies for the antigens that are NOT
present.
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antibodies (agglutinins) develop after birth in the plasma of the
blood
 4 Types: A, B, AB, & O.
What happens if we mix blood
types?
 A reaction outside the body between like antigens and
antibodies results in agglutination where the blood cells
clump together.
 A reaction within the body between like antigens and
antibodies results in hemolysis of the cells (they burst).
Rh Factors
 Three genes code for the the Rh antigens present on
the RBC cell membrane.
 Rh+ – Rh anitgens are present on the RBCs
 Rh- – Rh antigens are not present on the RBCs
 Normally the plasma does not contain Rh antibodies.
 Rh- individuals that receive Rh+ blood can have their
immune systems develop Rh antibodies that will
remain in the blood.
Circulatory System Functions
 regulates osmotic balance
 regulates pH
 transports nutrients and gases
 carries hormones
 regulates temperature
 is part of the immune system
Blood Vessels
 Blood vessels are part of a closed extensive network of
narrow elastic passageways whose main function is to
circulate blood to all the far out places of the body.
 In a closed system would take blood go along this
route: heart > arteries > arterioles > capillaries >
venules > veins and then back to heart.
 There are two kinds of blood vessels: arterial arteries
(carry blood away from the heart) and venous veins
(carry blood toward the heart to be re-pumped).
Arteries & Arterioles
 Arteries have to bear high hydrostatic pressures
created by the heart, they are composed of three main
layers:
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a outer layer of connective tissue;
the middle layers are composed of a thick-walled layer made
of smooth muscle (to resist high pressure), containing a layer
of collagen fibres (to give elasticity),
and a smooth inner connective tissue layer lined with
endothelial cells (to protect red blood cells from mechanical
damage)
 The aorta is the largest artery in the body and the
primary blood vessel which carries oxygenated blood
out of the heart to the rest of the body.
Capillaries
 Capillaries are the “heart” of the circulatory system, all
the action is in the capillaries, and all other blood
vessels merely assist them.
 Capillaries, are the smallest blood vessels in the body
and form a network that allows blood and cells to
exchange substances (such as oxygen).
 Capillaries are very narrow (10 mm diameter, the red
blood cells that travel through capillaries are 6 mm in
diameter).
 Capillaries are made of thin endothelial cells (one layer
thick); the cells fit loosely, and nutrients go through
pores between the cells.
Physical Mechanism of the
Capillaries
 The blood flow across the capillary bed is regulated by
a sphincter muscle on the arteriole side, whenever
there is little need to supply blood to a given capillary
bed, the sphincter closes and blood bypasses the
capillary bed via an arterio-venal shunt.
 The reason for the shunt is to avoid the large pressure
drop across the bed caused by the small size of the
capillaries, which create a bottleneck.
 This bottleneck means that, on the arterial side of the
capillaries (before the blood enters capillary bed),
blood is under high pressure, whereas the blood at the
venal side (at the end of the capillary bed) is under low
pressure.
Capillary Fluid Exchange
 The high hydrostatic pressure on the arterial side
squeezes water and nutrients out of the capillaries.
 Water leaving the capillaries builds up the osmotic
pressure because since the blood components
become more concentrated.
 Towards the venal end, water and waste materials are
sucked into capillaries by the osmotic pressure.
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Veins & Venules
 Veins are blood vessels in which blood flows toward
the heart conveying deoxygenated blood.
 The tissues of the veins are thinner, less flexible, and
less muscular than the arteries because there is little
pressure to bear.
 The veins have pocket (venous) valves to prevent
back-flow.
 The skeletal muscles work with the valves to move the
blood back to the heart.
 The venules are the smallest vessels that collect blood
from the capillaries and join to form veins.
The Heart
 The heart is just a pump.
 The heart is fist-sized muscle.
 Through its pumping action it helps to circulate blood
through the body.
 The heart must be unceasingly supplied with rich fresh
oxygen and used blood must be returned to the lungs
for reoxygenation.
 It has a right and left side partitioned by a sinewy wall
of muscle called a septum .
Atria & Ventricles
 Atria
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The upper chamber of the heart has two atria, the right atrium
and the left atrium.
The atria serve as a holding cache for blood that enters the
heart.
 Ventricle
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The lower chamber of the heart has two ventricles , the right
ventricle and the left ventricle.
The left ventricle has the responsibility of pumping blood to the
entire body and therefore is somewhat bigger and more
muscular than the right ventricle, it has an opening that blood
flows through to the aorta (the central artery where blood
circulation originates throughout the body).
The Double Pump
 In order to split the work, a double circulation evolved
that has one pump for each capillary bed.
 The heart consists of a double pump:
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the pulmonary circuit – the right atrium/ventricle combination
pumps deoxygenated blood to the lungs; and
the systemic circuit – the left atrium/ventricle pumps
oxygenated blood through the body capillaries.
 In the double system, deoxygenated and oxygenated
blood take separate routes through the heart.
The Pulmonary Circuit
 The system of blood vessels that carries deoxygenated
blood to the lungs and oxygenated blood back to the
heart.
 The deoxygenated blood arrives from body via
capillaries > vena cavae > right atrium > right ventricle
> pulmonary artery > lungs (alveoli) > pulmonary veins
> left atrium
The Systemic Circuit
 The system of blood vessels that carries oxygenated
blood to the tissues of the body and deoxygenated
blood back to the heart.
 The oxygenated blood arrives from the lungs to the left
atrium>left ventricle > aorta > the rest of the body
Setting the Heart’s Tempo
 The heart is made of specialized muscle, cardiac
muscle, which is incredibly resistant to fatigue. Your
heart must contract 2-3 billion times during your
lifetime.
 The heart is myogenic, that is, it initiates own
contractions and does not need the brain to do it.
 The Heart’s pacemaker, called the sinoatrial (SA) node
is located near the entrance to the right atrium, causes
simultaneous contraction of both atria and then both
ventricles.
 Gap junctions in cardiac cells help rapid spread of the
impulse to all cells irrespective of distance from the
pacemaker.
The Heart Beat
 Activation of heart beat:
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the impulse from the SA node spreads on the walls of the atria;
it arrives at the atrioventricular (AV) node, placed along the
inter-ventricular septum;
the impulse follows these fibres to the ventricles;
and spreads along the ventricle walls through Purkinje fibres.
Lubb-Dubb
 The two sounds of a beating heart are made by the
closing atrioventricular and aortic valves and
correspond to the two phases of the heart cycle:
systole and diastole.
 Systole is the contraction of the atria, during which the
ventricles fill with blood, followed by contraction of the
ventricles, which pushes blood out past the aortic valve
to the arteries. To prevent back-flow to the atrium, the
atrioventricular valve closes, making a sharp sound.
 Systolic contraction is followed by relaxation of the
heart, diastole. Relaxation of the ventricles results in
loss of pressure in the heart and closure of the aortic
valve by the pressure in the aorta.
Heart Regulation
 Although the heart initiates its own beat, the nervous
system can accelerate the heartbeat (via the
sympathetic nerves) or slow down the beat (via the
vagus nerve).
 The heart is also under hormonal control. For
example, the hormone adrenaline accelerates the
heart beat.
Cardiovascular Diseases
 Heart attack (myocardial infarction):
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is caused by heart ischemia (lack of O2) usually caused by
obstruction by a blood clot.
 Stroke (cerebral infarction):
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clot in the brain or rupture of a weak blood vessel.
 Atherosclerosis:
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thickening of artery walls, which narrows the atrial lumen, is
the leading cause of death.
Blood Pressure
 The pressure of the blood on the walls of the blood
vessels. Measured in two numbers.
 The first, systolic pressure (top number), measures the
pressure of the blood against the artery walls as the
heart contracts.
 The second (bottom number), diastolic pressure,
measures the pressure against the artery walls when
the heart relaxes between beats.
 Normal blood pressure is 120/80 mm Hg.
Lymphatic System
 Sponge and re-circulate:
 A lot of water is lost in the blood capillaries, the lymphatic system
collects this water from the tissues and empties it into the circulatory
system.
 Lymphatic vessels are thin walled and have valves for unidirectional
flow like the veins.
 They join to form the thoracic duct and right lymph duct, which empty
near the heart.
 Transportation:
 Another function of the lymphatic system is to transport lipids and
molecules that are too large to cross the walls of capillaries, e.g.,
some hormones and large proteins.
 Immunity:
 The lymphatic system is also a part of the immune system.
 Lymphocytes (white blood cells) congregate in lymph nodes.
Components of Blood Diagram
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Cells of the Blood
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Erythrocyte Structure
Source: www.bio.psu.edu/.../Biol142/ blood/bloodlab.html
Hemoglobin Structure
Source: www.bio.psu.edu/.../Biol142/ blood/bloodlab.html
Types & Functions of WBC
Source: http://www.colorado.edu/epob/epob1220lynch/image/figure11a.jpg
ABO Blood Type Compatibility
Source: http://opbs.okstate.edu/~melcher/MG/MGW1/MG11121.html
Major Arteries & Veins
Copyright © 2002 by Nelson Thomson Learning, a division of Thomson Canada Ltd.
Arterio-Venal Shunt
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Capillary Fluid Exchange Diagram
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Venous Valves
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Heart Diagram
Copyright © 2002 by Nelson Thomson Learning, a division of Thomson Canada Ltd.
Blood Circulation in the Heart
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Pulmonary Circuit Diagram
Copyright © 2002 by Nelson Thomson Learning, a division of Thomson Canada Ltd.
Systemic Circuit Diagram
Copyright © 2002 by Nelson Thomson Learning, a division of Thomson Canada Ltd.
Heart Beat Diagram
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Heart Sounds
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Lymphatic System Components
Source: http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/30_Circulatory.htm
Sources:
 http://fajerpc.magnet.fsu.edu/Education/2010/Lectures/
30_Circulatory.htm
 http://learning.mgccc.cc.ms.us/science/blood/index.htm
 http://library.thinkquest.org/2935/Natures_Best/Nat_Be
st_High_Level/Circulatory_Net_Pages/Circulatory_pag
e.html#blood