Download The Circulatory System - share1

The Circulatory
System
NATALIA JANZEN AND HEATHER CARPENTER
Draw This
No, it doesn’t have to
be pretty, or colorful,
or proportionate. But,
you will understand
more of all of the
cardiovascular stuff
we are about to
throw at you if you
have an idea of what
the heart looks like.
http://ibguides.com/biology/notes/the-transport-system
The Function of the Cardiovascular System

Many believe that the purpose of the circulatory system is to
pump blood
 Though
not entirely inaccurate, the main function of the
circulatory system is to pump different things in the blood,
namely:
 Oxygen/Carbon
 Nutrients
 Hormones
 Antibodies
 Urea
 Heat
Dioxide
The Big Picture
https://www.youtube.com/watch?v=9fxm85Fy4sQ
A Summary of the Big Picture

Arteries = leave the heart
 Arteries=

high pressure blood
Veins = enter the heart
 Veins
= low pressure blood

Right = deoxygenated blood

Left = oxygenated blood

Atria = collect blood

Ventricles = pump blood out
Right
1.
The right atrium collects blood from
the superior and inferior vena cava
2.
Blood flows through the
atrioventricular valves into the right
ventricle, where the semilunar valves
are closed
3.
4.
The right atrium contracts, closing the
atrioventricular valves to prevent
backflow
The closed valves create a rise in
pressure in the right ventricle, causing
the semilunar valves to open
5.
Blood flows from the right ventricle to
the pulmonary artery
6.
A contraction of the right ventricle
closes the semilunar valves,
preventing backflow, and starting the
process all over again
The Little Picture: How the Heart
Pumps Blood
1.
2.
3.
4.
5.
6.
Left
The left atrium collects blood from
the pulmonary veins
Blood passes through the
atrioventricular valves into the left
ventricle, where the semilunar valves
are closed
The left atrium contracts, closing the
atrioventricular valves to prevent
backflow
The closed valves create a rise in
pressure in the left ventricle, causing
the semilunar valves to open
Blood flows from the left ventricle to
the aorta
A contraction of the left ventricle
closes the semilunar valves,
preventing backflow, and starting
the process all over again
The Even Littler Picture: How the Heart Pumps Blood
https://www.youtube.com/watch?v=oHMmtqKgs50

Impulses from the medulla in the brain control heart rate by sending electrical
signals to the sinoatrial node

The sinoatrial node sends electrical impulses to the rest of the heart to stimulate
contraction

Contraction is stimulated in the atria first, by the sinoatrial node

Contraction of the ventricles occur second, as the electrical impulse passes
through the atrioventricular node

There is a delay between the reception and dispersion of the electrical signal
at the atrioventricular node
 This
allows for atrial systole (a fancy way of saying the contraction), before
the ventricles also contract
 The
contractions of the valves are what we hear as heart beats – there
are two separate ones
https://www.youtube.com/watch?v=EA2DY0tjpFI
The Microscopic Picture: Cardiac Muscles & More

Purkinje Fibers: carry electrical impulses from
the bundle branches to the myocardium
(muscle tissue of the heart)

The muscle tissue is made of cardiac
muscles

The structure of cardiac muscles allow for
the quick dispersion of electrical impulses
throughout the heart

Cardiac muscles are made of individual
muscles cells, called cardiomyocytes

Cardiomyocytes connect to form
intercalated discs, which work together as
the syncytium

Electrical resistance in intercalated discs is
extremely low, allowing for the free flow of
ions, and the quick transmission of electric
signals
http://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart
http://www.meddean.luc.edu/lumen/meded/Histo/HistoIm
ages/hl3A-48.jpg
Order of Electric Impulse Signals
1.
sinoatrial node
2.
atrioventricular node
3.
atrioventricular bundle
4.
left and right bundle branches
5.
Purkinje fibers
6.
myocardium
7.
syncytium
8.
intercalated discs
9.
cardiomyocytes
What happens when all of that doesn’t work properly?



Arrhythmia

Arrhythmia occurs when the normal sequence of electrical impulses does not work
properly

This causes the heart to beat too fast, too slow, or too erratically, which interrupts blood
flow
Pacemakers

Pacemakers are small devices that are put in a patients chest (usually), that send out
electrical impulses in order to regulate heartbeat

Used to treat arrhythmia
Defibrillators

Defibrillators are often used in life-threatening situations, such as cardiac arrest

It delivers an electrical shock to the heart in order to stop any cardiac dysrhythmia and
lets the body restore the proper heart rate with the sinoatrial node.
The Rest of the Cardiovascular System
THE FLOW OF BLOOD THROUGHOUT THE BODY
The Arteries: Function and Description

Remember that the arteries are responsible for any blood flow away from the
heart

The arteries convey blood at high pressure from the ventricles to the tissues of
the body

The aorta is the largest artery in the body and is the thickest of the blood
vessels in the body. It runs the length of the body’s trunk.
 This
includes the aortic arch, a 180 degree turn in the aorta at the top of
the heart, where the blood is pumped into the artery. It branches off into
three different arteries
The Arteries: Structure

Arteries have a thick outer layer of longitudinal collagen and elastic fibers that help
prevent leaks and bulges

They have thick walls that help them withstand the high pressure

Arteries have thick layers of circular elastic fibers and muscle fibers that help them
move the blood after each heart contraction


These fibers and muscles cells help regulate the blood pressure between pump
cycles
Narrow lumen (the inside or hollow part of a tubular structure) helps maintain the high
blood pressure in the arteries.
The Capillaries: Function and Description

The blood vessel that assists in transporting blood through the body’s tissues

They connect the arteries and the veins


The arteries bring oxygen rich blood into the capillaries

The veins take deoxygenated blood out of the capillaries
Capillaries are found in a bundle of cells known as capillary networks
The Capillaries: Structure



The capillary wall is about one cell thick

The thickness aides the capillary’s permeability, because diffusion only has to occur over a
very small space

Because of the high permeability of a capillary, and the fact that its wall is easy t diffuse
across, diffusion happens a lot in the capillaries
The capillaries often exchange materials between cells in tissue and blood in the
capillaries through pores in the walls of the capillary

Plasma leaks out of blood to form tissue fluid

Phagocytes can also escape, and are beneficial in fighting infection
The lumen of the capillaries is extremely small/narrow

More capillaries can fit into small spaces, which increases the surface area for diffusion
The Veins: Function and Description

Veins are responsible for blood flow into the heart

They collect blood that is at low pressure from the tissues of the body and return
it to the atria of the heart

There are valves present among veins that prevent the backflow of blood
throughout the body
The Veins: Structure

The walls of veins are thin layers of a few circular elastic fibers and muscle fibers


Veins can become flat when pressed against by other muscles


This helps push the blood along towards the heart
There is only a small layer of longitudinal collagen and elastic fibers on the vein
walls


Blood does not flow in pulses, so the vein walls do not need to be thick in order
to move the blood along
The low pressure in the veins means they are less likely to burst
Veins have wide lumens, in order to maintain a low blood pressure and
accommodate a large amount of slow-moving blood at once.
http://www.majordifferences.com/2013/02/differen
ce-between-artery-and-vein.html#.VS-QBsJFDIU
http://leavingbio.net/circulatory%20system/circul
atory%20system.htm
http://alexalex.wikispaces.com/Transportation+
System
Summary of Blood flow by Vessels throughout the Body
heart  arteries  capillary networks  veins  heart
https://www.youtube.com/watch?v=VVJJHw_Ocp4
http://antranik.org/wp-content/uploads/2012/05/bloodflow-of-the-heart.jpg?9873a6
What happens when that doesn’t work?

Coronary Artery Disease

CAD is caused by a buildup plaque in the arteries due to a condition known as
atherosclerosis

The cholesterol in food can deposit into blood vessel walls, creating a plaque buildup

This buildup creates blockages in the blood flow system of the body, which could lead to
blood clots or heart attacks

The plaques cause the artery walls to be sticky, so any non-liquid elements of blood have
a greater chance of sticking to the plaque and building it more

A person is most at-risk for blood clots and heart attacks during physical activity, because
there is not enough time for the blood cells to circumvent the plaque in order to supply
the muscles with oxygen-rich blood

CAD is usually the result of a cholesterol-laden diet

Height as a factor? Research
What happens when that doesn’t work?


Hypertension

Hypertension is just another way of saying high blood pressure

Blood pressure is determined by the amount of blood your heart pumps and the
amount of resistance to blood flow in the arteries

High blood pressure is the result of the heart pumping more blood than into narrower
arteries

Hypertension generally develops over several years and can be the effect of
medications, substance abuse, or an unhealthy diet

It is usually treated with medication
Thrombosis

The forming of a blood clot inside of a blood vessel

Can result in hypoxia (oxygen deprivation), and, more seriously, in anoxia (complete
oxygen deprivation, resulting in loss of tissue)
Skills and Applications
THE WAY IB WANTS YOU TO USE THIS INFORMATION
Heart Rate


How to measure heart rate

Place two fingers on the side of the neck over the jugular

Count how many beats you experience in one minute

The normal resting heart rate for adults are anywhere from 60-100 beats per minute

The harder your body is working (physical exertion ect.) the higher the heart rate will
be
Abnormal:

Above 100 beats per minute = Tachycardia

Below 60 beats per minute = Bradycardia
Blood Pressure


Systolic

Higher of the two numbers (the top #)

Measures the pressure in the arteries when the heart muscle contracts

Normal = less then 120
Diastolic

The bottom number

Measures the pressure in the arteries between heart beats when the
heart is resting

Normal = less than 80