Transcript blood vessels

You Gotta Have
The Circulatory System
Circulatory System Consists of…
• Blood
• Blood
• Heart
Vessels
Overview
The Heart pumps blood through the
body through blood vessels
(arteries, capillaries and veins)
• Arteriestake blood away from the
heart, veins return blood to the
heart
• Blood carries O2 (food) towards and
CO2 (waste) away from tissues
• The lungs are not part of the
circulatory system!!
•
Circulatory System
BLOOD VESSELS
Two Pathways
•
Pulmonary Circulation
– Carries blood to lungs and back
•
Systemic Circulation
– Carries blood to body and back
Your Blood Vessels:
Pathway of Circulation
•
3 types of vessels
– Arteries(Shown as Red
because blood has O2)
– Capillaries(Red and Blue
because some O2 lost to
tissues)
– Veins(Shown as Blue
because O2 lost to tissues)
Red Blood and Blue Blood
Blood is never blue!!!!!!!!!!!!!!!!!!
• Oxygenated blood is bright red and
deoxygenated blood is dark red
• Veins appear blue because of the way light
reflects off the blood vessel
• We don’t see arteries because they are too
deep.
• We draw them blue to distinguish them on
diagrams and simplify things
•
Arteries vs. Veins
What you need to know about the
STRUCTURAL differences between Arteries
and Veins:
-Artery walls are much thicker, very elastic
and have more muscle.
-Veins are thin walled and contain valves to
psh the blood along
Arteries vs. Veins
•
Why are arteries and veins the way
they are?
– Blood is under very high pressure when
it leaves the heart and enters the
arteries
• Therefore, arteries need to be strong!
– Once it has left the tissues and enters
the veins, the blood is under a very low
pressure
• Therefore, veins are weak
Arteries:
carries blood Away from heart
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–
Large
Thick-walled, Muscular
Elastic
Oxygenated blood
•
Exception Pulmonary Artery
– Carried under great pressure
– Steady pulsating (used to measure pulse)
Arterioles: smaller vessels, enter tissue
Capillaries
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–
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Smallest vessel
Microscopic
Walls one cell thick
Located at the tissue
Nutrients and gases
(O2, CO2) diffuse here
Veins:
Caries blood to the heart
–
Carries blood that contains
waste and CO2
•
–
–
Exception pulmonary vein
Blood under low pressure
Valves to prevent back flow
due to gravity
Venules: small veins, larger than
capillaries
Blood Vessels
http://www.kscience.co.uk/animations/blood_system.swf
Animation of blood flow
The Aorta – The largest blood vessel
http://www.kscience.co.uk/ani
mations/vessels_label.swf
Blood Vessel Animation
Circulatory System
BLOOD
The Blood
•
•
Body contains 4-6 L
Consists of
– Water
– Red Blood Cells
– Plasma
– White blood cells and
platelets
Your Blood: Fluid Transport
Liquid Portion Carries
• Blood cells (made in bone marrow)
– Erythrocytes (RBC - red blood cells)
– Leucocytes (WBC - white blood cells)
• Platelets (fragments of the cells in bone
marrow – no nucleus)
• Proteins
• Nutrients - digestive system
• Gases - Respitory system
Oxygen in the Blood
•
Hemoglobin , iron
containing molecule
•
Loosely picks up oxygen
in the lungs
•
Releases oxygen in
areas low in oxygen –
body tissues
O2
O2
O2
O2
Carbon Dioxide in the Blood
•
Hemoglobin also carries CO2
•
CO2 is a waste product of cellular
respiration
•
Travels to the lungs to be exhaled
What does blood contain?
•
50% Water
•
45% Erythrocytes (RBC)
•
4% Plasma with Substances
•
1% Leukocytes (WBC) + Platelets
Erythrocytes (RBC)
Transporters of
– Oxygen
– Carbon dioxide
• RBC
– Lack a nucleus
– Contain hemoglobin
– Disk-shaped
• RBC are produced in the
bone marrow
• Lives for ~120 days
• Old RBC are destroyed in
liver and spleen
•
Leukocytes (WBC)
WBC fight infection
•
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Less abundant
Created in bone marrow
Some live for months
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Attack foreign substances
Most just a few days
Several types
ALL contain nuclei
Difference between red
and white ?
Platelets
PLATELETS are for
CLOTTING blood
• Cell fragments
• Produced in bone marrow
• Short life span (1 week)
• Form a web trapping blood
cells
•
Blood Clotting
Break in Capillary Wall
Clumping of Platelets
Clot Forms
Blood vessels injured.
Platelets clump at the site
and release a protein
Protein creates a net
creating a clot. The clot
prevents further loss of
blood.
Circulatory System
HEART
Your Heart
•
Pumps blood around
your body to keep you
alive!
•
If your heart stops you
will die!
Heart:
Structure and Function
•
•
Keeps blood moving
Large organ composed
of
– Cardiac Muscle
– Rich in Mitochondria
The Structures of the Heart
Superior Vena Cava
Large vein that brings oxygen-poor blood from
the upper part of the body to the right atrium
Aorta
Brings oxygen-rich blood from the left
ventricle to the rest of the body
Pulmonary Arteries
Bring oxygen-poor blood
to the lungs
Pulmonary Veins
Bring oxygen-rich blood from each
of the lungs to the left atrium
Left Atrium
Right Atrium
Left Ventricle
Inferior Vena Cava
Vein that brings oxygen-poor
blood from the lower part of
the body to the right atrium
Right Ventricle
Structure of Heart (cont)
•
Four chambers
– Two upper (Atria)
• Walls thinner
• Less Muscular
– Two lower
(Ventricles)
• Walls thicker
• More muscular
• Do more work
http://www.kscience.co.uk/animations/heart_label.swf
Heart Structure Animation
Blood Flow Through the Heart
©COPY 1997 HeartPoint
Bloods Path Through the Heart
•
Both Atria fill at same time
– Rt atrium receives oxygen poor blood from body
from vena cavas
– Left atrium receives oxygen Rich blood from
lungs through four pulmonary veins
•
After filled with blood atria contract,
pushing blood into ventricle
Both ventricles contract
Right ventricle contracts and pushes oxygenpoor blood toward lungs
• through the pulmonary arteries
Bloods Path Through the Heart
Left ventricle contracts and forces oxygen
rich blood out of heart
• Through Aorta (Largest Vessel)
The cardiac cycle
http://www.kscience.co.uk/animations/blood_system.swf
Animation of blood flow
Control of Heart Rate
Resting Heart Rate
Heart Rate during exercise
Control of the Heart
The Heart is controlled by nerves and hormones:
Nerves:
•
– Its own nerves Pacemaker which keeps a
constant beat
• Heart will beat even if it is disconnected from the brain
• Can be substituted by an artificial pacemaker
- The Brain can speed-up (exercise) or slow
down the heart (sleep) if needed
Control of the Heart
Hormones:
•Certain
hormones such as epinephrine
(adrenalin) impact how the heart
operates
Your Heart: The Vital Pump
•
At REST, the heart
beats about 60-80
times per minute
(~4.7L)
•
During EXTREME
EXERTION (exercise) it
can beat between 150200 times per minute
(~38L)
Heart Rate Discussion
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Why??
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Brain sends a signal to increase HR
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Adrenal Gland secretes epinephrine
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Both work together to increase blood flow around
the body
•
Increased blood frow = increase 02/glucose delivery
to cells and CO2 removal
DISORDERS
Coronary Artery Disease
Your heart needs Oxygen too!
•
– Is supplied with Oxygen by coronary arteries
– Coronary arteries can become partially blocked
by plaque (fat and cholesterol mainly)
• Causes by lifestyle choice and genetics
– This block limits the amount of oxygen delivered
to the heart
– Can cause tiredness, dizziness and pain
Coronary Artery Disease
•
•
Can be diagnosed with an angiogram whereby a
fluorescent dye is injected into the bloodstream.
This dye shows up on an x-ray and shows where
flow is disrupted
Disorders (cont)
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Heart Attack
– Coronary artery(ies) become completely blocked
No Oxygen can reach the heart muscle
• Heart muscle begins to die and eventually stops beating
• Symptoms
– Nausea, Shortness of breath, Severe chest pain, sweating, dizziness,
fatigue
IMMEDIATE MEDICAL ATTENTION NECESSARY
Disorders (cont)
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Stroke
– Heart atack for the brain
– Blood cannot reach the brain
due to a blockage in its blood
vessels
– Brain cells die due to lack of
oxygen
– Can lead to paralysis,
• loss of ability to speak
• death
Current PREVENTION Recommendations
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Regular exercise
Weight control
Well balanced diet
Do not smoke
Diet low in saturated
fat
http://www.pbs.org/wgbh/nova/eheart/transplantwave.html
Heart Transplant Interactive Activity