Download Circulatory System

Biology 20
Circulation
Blood
Lymphatic System
Immunity
The Importance of the
Circulatory System
 96
000 km of blood vessels
 60
trillion cells in body
 no
cell is more than 2 cells away from a
blood vessel
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3
Functions of the Circulatory
System

3 main functions:
1) transports gasses, food, wastes, and hormones
2) carries molecules and cells that help defend against
invading organisms
3) distributes heat throughout the body
4
Blood Vessels

Arteries

carry blood away from heart

elastic

stretch to accommodate blood surge from heart
• pulse

thick walls to allow for stretch

high blood pressure
5
Blood Vessels
 Arterioles

small arteries
• arteries branch into many arterioles



connects to capillary
contains smooth muscle which can
contract or relax according to nervous
impulses
sympathetic nerve impulses affect
diameter of arterioles:
• Vasodilatation -- open
• Vasoconstriction -- constricts
6
Blood Vessels
 Capillaries


links arterioles to venules
site of exchange of nutrients and wastes
between blood and interstitial fluid
• I.F. is the fluid that surrounds and bathes body
cells




smallest blood vessels
single layer of cells
big enough for only 1 RBC to pass through
at a time
easily crushed = bruise
7
RBC in a capillary
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Blood Vessels
 Venules

small veins

smooth muscle

large end of capillaries
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Blood Vessels

Veins



carry blood towards the heart
larger diameter than arteries
lower pressure than arteries
• (2 mmHg compared to 100 mmHg in arteries)

pull of gravity
PROBLEM!!
What forces the blood through a vein?

blood pressure is not high enough to “suck”
blood back to the heart
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Blood Vessels

Solution!!

Veins have one-way valves
• only allow blood to move in one direction


skeletal muscles help veins in getting blood to the
heart -- squeeze veins
wall is not as thick as arteries because blood
pressure is lower – no surge of blood flow
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One Way Valves
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Arteries, Veins, Capillaries
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Arteries, Veins, Capillaries
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Major Vessels of the Body

Superior Vena Cava


Inferior Vena Cava


Artery from right ventricle to lungs
Pulmonary Veins (4)


Vein to heart from lower body
Pulmonary Artery


vein to heart from upper body
Veins from lungs to left atrium
Aorta

Artery from left ventricle to body
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Major Vessels
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The Heart

Structure


roughly in center of chest in thoracic cavity
protective membrane
• pericardium forms a fluid filled sac to reduce friction


size of fist
two separate pumps
• right and left

sides are separated by a septum which
prevents mixing of oxygenated and
deoxygenated blood
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The Heart
 Label

the diagram of the heart.
Identify the following structures
(next slide)

Outline the direction of flow of blood through
the heart
• Differentiate between oxygenated blood and
deoxygenated blood by using red and blue
arrows on diagram

List the general function of each structure.
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The Heart









Right Atrium
Superior Vena Cava
Inferior Vena Cava
Right AV Valve
(Tricuspid)
Right Ventricle
Pulmonary Artery
Pulmonary Valve
Pulmonary Vein







Left Atrium
Left AV Valve (Bicuspid)
Left Ventricle
Aorta
Aortic Valve
Coronary Arteries
Interventricular Septum
Chordae Tendinae
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The Heart’s Structures

Atria
 Structure
• thin walled chamber

Function
• right atria - collect deoxygenated blood from body
and head, and pass to ventricles.
• left atria - oxygenated blood from the lungs, and
pass it to ventricles.
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The Heart’s Structures

Ventricles

Structure
• thick muscular walls
• larger than atria
• one side is thicker than the other

Function
• right ventricle pumps deoxygenated blood to lungs
• left ventricle pumps oxygenated blood to body
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The Heart’s Structures
 Interventricular

septum
Wall of muscle that separates the right atrium
and ventricle from the left atrium and
ventricle.
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The Heart’s Structures

Superior Vena Cava



Inferior Vena Cava



Vein to right ventricle of the heart from upper body
Carries deoxygenated blood
Vein to right ventricle of the heart from lower body
Carries deoxygenated blood
Aorta


Artery through which the left ventricle pumps blood to
the body
Carries oxygenated blood
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The Heart’s Structures

Pulmonary Artery





Pulmonary trunk – split into left and right arteries
Artery from right ventricle carries deoxygenated blood
to lungs
Right pulmonary artery goes to right lung
Left pulmonary artery goes to the left lung.
Pulmonary Veins (4)



Veins from lungs carry oxygenated blood to left atrium
Right pulmonary vein from right lung
Left pulmonary vein from left lung
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The Heart’s Structures

Atrioventricular valves (AV Valves)


The right AV valve is called the tricuspid valve
and the left AV valve is called the mitral valve
Structure
• flaps of tissue between atria and ventricles
• attached to heart muscle by chords



chordae tendinae
cords prevent flaps from inverting
Function
• Separate atria from ventricles
• prevents back flow of blood from ventricles into atria
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The Heart’s Structures

Pulmonary valve


Aortic valve


Allows deoxygenated blood from right ventricle into
pulmonary artery, but does not allow it to flow back
into the ventricle.
Allows oxygenated blood to flow from the left ventricle
to the aorta, but not to return back to the ventricle.
Structure

Thin flap, half-moon shaped
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The Heart’s Structures
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Three Circulatory Systems
1) Pulmonary Circulation

From the heart to the lungs
and back to the heart
2) Coronary Circulation


From the heart chambers to
the heart muscles and back
to the heart chambers
system of arteries, capillaries
and veins within heart
3) Systemic Circulation

From heart to all other parts
of the body and back to the
heart.
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Systemic Circulation

Involves 2 smaller systems

Renal Circulation
• To the kidneys

Hepatic Circulation
• From the digestive tract, through liver, then to heart

Important vessels

Carotid Arteries and Jugular Veins
• head

Brachial Artery and Brachial Vein
• arms

Femoral artery and Femoral Vein
• legs
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Biology 20
Heart Beat
Heart Sounds
Heart Rate
Blood Pressure
Initiating the Heart Beat
 Cardiac
muscle contracts without external
nervous stimulation
 Sino-Atrial Node (SA Node)




Pacemaker
Coordinates contractions
Special muscle and nerves located in the right
atrium
70 beats/minute
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Initiating the Heart Beat

The SA node sends nerve impulses:

across atria
• contract now!!

To second node
• AV node
• Atrial-ventricular node
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Initiating the Heart Beat
 AV




node
mass of nerve tissue in septum
passes nerve impulse through septum
to the bottom of ventricles
Impulse conducted upwards through
nerves in the ventricles
Contraction of ventricles begins
• Contraction begins at apex

Bottom to top contraction
 Result…

Atria contract followed by the ventricles.
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Setting the Heart’s Rate
 Autonomic

Nervous System in charge!
Sympathetic nerves
• stimulated during times of stress
• Increases heart rate

Parasympathetic nerves
• stimulated during times of non-stress
• returns heart to slow rate
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Setting the Heart’s Rate
 Problem:


SA node malfunction
Ventricular fibrillation
• disorganized and random contraction of heart cells
• no longer pumps blood


death
Solution:
• First -- Electro shock to halt the “short circuit”
• Then -- installation of an artificial pacemaker
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Electrocardiogram

Electrodes are placed on the body surface



Connected to a recording device
Electrical impulses from heart are displayed
on a screen.
P wave
• atrial contraction

QRS wave
• ventricular contraction

Used to diagnose heart problems


more evident during heavy exercise
Doctors identify dead patches of heart muscle
which will not conduct impulses.
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Cardiac Cycle
 One

heart beat
Systole
• ventricles contract

Diastole
• ventricles relax
 70
- 75 beats/min
 two sides of heart beat in unison

first the atria then the ventricles
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Stages of the Cardiac Cycle
 1)

Heart relaxed -- atria filling
Right Atrium
• blood from Superior & Inferior Vena Cava

Left Atrium
• blood returning from lungs via 4 pulmonary
veins
 2)

Atria Contract
Ventricular diastole
• Ventricles fill up

blood pushed from atria into ventricles
past the AV valves
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Stages of the Cardiac Cycle
3) Ventricles Contract

ventricular systole
• AV valves close
• Semilunar valves open

Right ventricle
• blood through pulmonary artery to lungs

Left Ventricle
• blood through aorta to rest of body
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Heart Sounds
 “lubb
dubb”
 Systole (lubb)



longest and loudest
ventricles contract
caused by AV valves closing
 Diastole


(dubb)
caused by semilunar valves closing
ventricles relaxing
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Blood Pressure
 Measures
amount of pressure in artery
 Two parts (120/80)

Systolic pressure
• high number (120)
• pressure in artery when ventricles contract

Diastolic pressure
• low number (80)
• pressure in artery when ventricles relax
• Most important in diagnosis of heart health.
 Measured
using a sphygmomanometer!!
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Steps in finding Blood
Pressure
1) Inflate cuff beyond normal pressure
• this squeezes the artery closed
2) Leak, Look and Listen
• release pressure slowly
• listen to stethoscope for thump

blood forcing its way through the cuff
• read the number on the dial at that point
• this is systolic pressure
3) Wait and Listen
• When thumping stops, blood is moving
unrestricted
• this is diastolic pressure
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Problems / Diseases
 Hypertension



high blood pressure
140/90
can lead to heart attack, stroke, kidney
damage
 Caused

by:
high blood volume
• water, salt,

constriction of blood vessels
• tumor on adrenal medulla causing
increased epinephrine
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Problems / Diseases
 Hypotension

low blood pressure

often associated with bleeding
• external or internal

body compensates by
• increasing cardiac output
• increasing peripheral resistances

arteriolar constriction
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Regulation of Blood Pressure
 Negative
Feedback Loop
 Monitor:

Baroreceptors
• in walls of aorta and carotid arteries
• measures blood pressure
 Control

Center:
Medulla Oblongata
• Blood pressure regulator in the brain stem
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Regulation of Blood Pressure

Regulators:

Sympathetic Nerve Stimulation
• arterioles constrict
• cardiac output increases

stroke volume & stroke rate
• increases blood pressure

Parasympathetic Nerve Stimulation
• arterioles dilate
• decreased cardiac output
• decrease blood pressure
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Regulation of Blood Pressure
 Example:


M. Oblongata processes info from
baroreceptors
BLOOD PRESSURE TOO HIGH
• decrease sympathetic nerve stimulation
• increase parasympathetic nerve stimulation


sends message to slow heart rate and dilate
arterioles
BLOOD PRESSURE TOO LOW
• decrease parasympathetic nerve stimulation
• increase sympathetic nerve stimulation


increase heart rate
constricts blood flow
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Biology 20
Blood & Immunity
Blood Functions
1.To carry partially digested food material from
the small intestine and oxygen from lungs.
2. To transport the waste products of
metabolism from the cells to the kidneys,
lungs and skin for elimination from the body.
3. To carry hormones from the endocrine
glands to the cells they control.
4. To control the amount of water and the level
of acidity inside cells.
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Blood Functions
5. to provide antibodies and white blood
cells that protect against infection.
6. to provide substances that will clot blood
if blood vessels are damaged.
7. to carry enzymes throughout the body.
8. to distribute heat produced during cell
metabolism.
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Blood Composition


blood is a liquid tissue composed of cells,
cell fragments and a watery medium called
plasma.
an adult male has 5-6 L of blood and an
adult female has 4-5 L of blood.
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Plasma


55% of blood volume
straw coloured liquid consisting of:
•
•
•
•


90% water
7% proteins (albumin, globulin, fibrinogen)
1% ions (Na+, K+, Cl-, Ca2+)
2% other substances (glucose, fats, amino acids, gases,
urea, hormones, etc.)
if blood is allowed to clot outside the body and the
clotted portion is removed, the fluid portion left is
called serum.
Serum, therefore, consists of plasma from which
the clotting proteins have been removed.
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Erythrocytes



major function is to transport oxygen
average male has - 5.2 million RBC's/mL blood
average female - 4.7 million RBC's/mL of blood
• low, due to menstruation

bioconcave discs containing hemoglobin
• iron containing protein pigments used in O2 and CO2
transportation.

amongst the most highly specialized of all cells:
• at maturity the nucleus and mitochondria disappear
and other cell structures dissolve
• provides room for 300 million hemoglobin
molecules/RBC.

life span of a RBC is approximately 120-130
days.
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Erythrocytes

old RBC have fragile cell membranes and are often
ruptured when passing through the spleen.

the hemoglobin released from RBC's is removed from
blood mainly by the liver

iron released into blood, other component called
bilirubin is secreted in bile
• reason why feces is brown
70
Anemia



a deficiency of RBC's caused by either too rapid a
loss or too slow production.
may be caused by blood loss, insufficient vitamin B12
or iron in diet, damage to bone marrow etc.
any condition that causes decreased oxygen being
transported to the tissue will increase the rate of
RBC's production
• e.g. blood loss, high altitude
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Leucocytes



combat infectious and toxic agents
average adult has 7000 WBC's/mm3 of blood
there are 5 kinds of leucocytes:
1) neutrophils
2) eosinophils
3) basophils
4) monocytes
5) lymphocytes

leucocytes function in 2 ways:
1) by destroying mutating agents by the process of
phagocytosis (#1,2,3,4)
2) by forming antibodies (#5)
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Leucocytes


lymphocytes are produced in the lymph glands
(lymphnodes)
•
spleen
•
thymus
•
tonsils
Lymph nodes are spongy tissue with 2 functions:
1)
remove foreign particles from lymph fluid before it
returns to general circulation
2)
produce lymphocytes (10 billion/day)
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Blood Formation


most blood cells are formed in soft centre portion of
marrow of long bones - sternum, ribs, vertebrae
special stem cells in marrow are parent cells of both
red and white cells
• early in development RBC's lose their nuclei and
mito.
• hemoglobin protein is added as they reach
maturity




(2 000 000 per second)
RBC's increase in number during periods of
strenuous exercise, emotional stress, at high altitudes
or high temp’s.
WBC are produced in lymphoid tissue of the body as
well and are produced in great quantities in times of
infection and disease fighting
platelets are also produced in marrow from tiny
pieces of cytoplasm that break off from the stem cells
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Blood Groups
How Many?
 Four

blood types:
A, B, AB, O
 Determined

by a marker on the cells
Antigen
• Stimulates formation of antibodies
• Antigen A = blood type A
 Antibody
in plasma must be opposite
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
Antibodies



Wrong bloodtype?



Produced in response to an invader
Attach to antigens --- clumping
Blood will clump (clot)
blockages
Agglutination - refers to the clumping of blood cells
caused by antigens (protein markers on cells) and
antibodies (proteins produced by B-lymphocytes in
response to a foreign antigen).
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Blood Types
OK
OK
OK
OK
Bad
OK
Bad
OK
Bad
Bad
OK
OK
Bad
Bad
Bad
OK
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
AB




Both antigens
Universal acceptor
Only donate to AB
O




Universal donor
No antigens on surface
Will not bind to antibodies
Only accept O
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Rh
Rh-factor
 The
Rhesus factor is another type of blood
group.
 People either have the antigen (Rh+) or do
not have it (Rh-).
 Erythroblastosis fetalis

Another antigen on RBC’s
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Rhesus Factor
 If

 If

present – Rh+
~ 85% of people
absent – Rh~15% of people
 No

natural antibodies for Rh
Can be produced
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Rh and pregnancy
 Rh
mother, Rh+ father
Baby can be Rh+
 First




child – no problem
No mixing
During birth, blood will mix
Mother’s immune system creates Rh+
antibodies
No harm to baby
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 Second






child
If child is Rh+ = problem
Mother has Rh+ antibodies
If they enter baby, blood will clump
Reduced O2 delivery
“blue baby”
Solution – transfuse baby w/ Rh- blood
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What is the most common blood type?
0
Rh-positive
38 percent
0
Rh-negative
7 percent
A
Rh-positive
34 percent
A
Rh-negative
6 percent
B
Rh-positive
9 percent
B
Rh-negative
2 percent
AB
Rh-positive
3 percent
AB
Rh-negative
1 percent
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Sickle Cell Anemia
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Blood Clotting
Platelets
 Small
 Fragile
 Contain
specialized proteins
 Initiate clotting


Join with calcium in plasma
First step in clotting
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Blood Clotting
Clotting involves up to fifteen different substances, but
can be summarized into three stages.

Release of thromboplastin from the platelets or
cells surrounding the injury

The conversion of prothrombin into an enzyme
called thrombin. Thromboplastin, calcium ions,
and several other substances activate this stage.

The conversion of fibrinogen into threads of fibrin.
Fibrin threads trap blood cells and forms a clot.
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+ Ca 2+
92
Blood Clotting



After clot forms, fibrin threads contract.
This further closes the blood vessel.
After the vessel has been repaired, the
enzyme plasmin dissolves the fibrin clot.
Clotting in an unbroken vessel is called
thrombosis, and is the most frequent
cause of heart attack and stroke.
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Needs
Calcium
94
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Fibrin Threads
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DISEASES OF THE BLOOD
1. ANEMIA
• deficiency of red blood corpuscles by either too
rapid a loss or too slow a production

Symptoms:
• lack of energy
• catch other illnesses easily
• sickle cell anemia
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DISEASES OF THE BLOOD
2. LEUKEMIA
• cancerous
organs
disease
of
blood-forming
• increase in immature white blood cells
• decrease in red blood cells and platelets
• decreases immunity and O2 capacity
98
DISEASES OF THE BLOOD
3. MONONUCLEOSIS
• “kissing disease”
• Viral disease
• increase in white blood cells production

monocytes
4. HEMOPHILIA
• Body is missing Clotting Factor IV
• Prevents normal clotting of blood
99
Lymphatic System
Lymphatic System
lymph the fluid found in lymph vessels that contains
some proteins that have leaked through capillary
walls
 A system to return extracellular fluid to circulatory
system


Much like the circulatory system


Leakage from capillaries
Intertwined
Lymph vessels

lymph capillaries are endings which are permeable to all
interstitial fluid

Fluid moves through lymph vessels by skeletal
muscle contractions

No backflow due to one way system of valves
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Some fluid seeps
through cap wall &
is called lymph
This fluid is
returned to the
blood via the
lymphatic
system
103

Lymph nodes






mostly in head, neck, armpit, abdomen, and groin
Before lymph is returned to the blood it passes
through lymph nodes
Nodes contain white blood cells
They filter lymph for invaders
Will destroy foreign particles
Lymph is returned to the circulatory system
through ducts
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Structure of the Lymphatic System
Ducts
• the vessels converge into the great
thoracic duct (GTD) or right lymphatic
duct (RLD)
• the GTD collects lymph from legs, left arm
and left side of head

empties into venuous system at the junction of
the left jugular and subclavian veins
• the RLD drains right arm, right side of head
and trunk
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Lymphati
c System
107
Functions of the Lymphatic
System
a. Return of Excess filtered fluid
• fluid filtered minus fluid absorbed = too much
left over at cell site.
• Extra fluid returned to blood to prevent edema

(collection of fluid in the interstitial tissues)
b. Return of protein to the blood
• capillaries slightly permeable to protein
• leaked protein must be returned to blood by
lymphatic
• purpose to maintain the protein concentration
difference between the plasma and the
interstitial fluid to prevent large movement of
fluid out of blood
108
Functions of the Lymphatic System
c. Specific transport functions


i.e. transports fat from the G.I. tract
other possibilities
• high molecular weight hormones reach the circulatory system
via the lymphatic system
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 Lymphoid


Organs
Spleen a lymphoid organ that acts as a
reservoir for blood and a filtering site for
lymph
thymus gland a lymphoid organ in which T
lymphocytes mature
110
Immune Response
Immunity
 The
immune system is designed to
respond to foreign cells, particles or virus
that are not supposed to be present within
the body.
 Of crucial importance is the body’s ability
to correctly distinguish “self” from “nonself”.
112
The Immune Response



WBC are involved in the Immune Response
the bodies first line of defence is the skin and
mucus membranes that prevent foreign substances
from entering
the second line of defence is the "inflammatory
response"
• histamines from injured cells triggers increased
permeability of capillaries in area, thus more WBC
can enter area
• the area becomes walled off and phagocytes invade
the area and rid the tissue of infectious or toxic
agents
• results in inflammation

when phagocytic leucocytes engulf a large
amount of bacteria and damaged tissue, they
die, resulting in pus formation (an accumulation
of damaged/dead tissue, and dead leucocytes).
113
Sick.
Immune Response

The third line of defence is antibody
formation (immune response)
• Highly specific (like enzyme-substrate specifically)
• Lymphocytes produce globular proteins known as
antibodies in response to an antigen (foreign
protein, virus or bacteria)

Antibodies protect the body against invading
agents by:
1) coat antigen so that phagocytic WBC's can ingest
it (yummy)
2) combine with it to inactivate it
3) work with another blood component called a
"complement" to lyse and destroy the infected cells
115
Immune Response


after the first bout of infection the
circulatory antibodies disappear, but
memory cells are now "sensitized" and if
particle returns they trigger quick
antibody production
other cells involved:
• T-lymphocytes (T-cells)
 mainly responsible for tissue transplant
rejection
• B-lymphocytes (B-cells)
 produce antibodies that circulate in blood
and lymph
• "T-helper cells”
 secrete substances which activate B-cells
to produce antibodies
116
Macrophage
 Macrophage

Surrounds and
destroys damaged
cells, proteins, and
pathogens
118
Helper T Cells
 Helper

T Cells
Helps identify invaders
119
B Cell
B

Cell
Makes and releases
antibodies and
memory cells
120
Memory Cell
 Memory

Cell
Stores information
about invaders
121
Antibody
 Antibody

Attaches to and
destroys invaders
122
 Pathogen


Can be bacteria,
protist, fungi, or virus
“invaders” or any thing
foreign
 Antigens


Specific shape
Attaches to pathogens
123
 Pathogen
enters body
(wound, infection, etc)
124
 Macrophage
surrounds and
destroys the pathogen
125
 Antigens
from dead
bacteria protrude from
macrophage
 Helper T Cells
identifies the antigen
on the macrophage
126
 Helper
T Cells relays
information to B Cells
 B Cells make and
release antibodies
accordingly
127
 Antibodies
attach to
antigens
128
 Antibodies
destroy
antigens
 B Cell make Memory
Cells that store
information on
invaders, making it
easier to destroy next
time
129
 Video
Time!
 http://www.learnalberta.ca/content/seb20/h
tml/immuneSystem/index.html
130