The Circulatory System

Cardiovascular System Facts The average person has nearly 100,000 km of blood

vessels running through them.

The larger the organism, the slower the heart beats (a

woman’s heart will beat faster than a man’s)

A blue whale’s heart beats 5 times per minute while a

hummingbird’s beats closer to 1400 times

Blood in your veins is not blue! They look blue due to

the way the light is absorbed and reflected in your

skin.

Your heart produces enough pressure to shoot blood

nearly 30 feet.

The Heart

The heart is the pump in our body which

stimulates the movement of the blood.

In an adult, it is about the size of a fist.

It is located roughly in the middle of the chest

between the lungs.

It is composed of 4 chambers.

The Heart

The four chambers of the heart are:

Right atrium

Right ventricle

Left atrium

Left ventricle

The Heart

The Heart

The atrium and ventricle on the respective sides

are directly linked

The left and the right side have no direct link.

They are separated by a partition, the septum.

For the left and right side, blood flows into the

heart through the atrium and is pushed out

through the ventricle.

The Heart

To prevent blood from flowing backwards in the

heart, valves are present in the heart

These valves are called the atrioventricular

valves.

Without these, blood would flow backwards

through the heart.

The Heart There are 5 major blood vessels connected to the

heart.

Superior and inferior vena cava

Pulmonary vein

Pulmonary artery

Aorta

The Heart

Function of the Heart The heart pumps blood to the entire body

First phase of a heart beat is diastole

The heart is at rest and the atriums fill with blood.

Next the atriums contract, pushing blood into the ventricles.

The final phase is when the ventricles contract, pushing blood out into the arteries.

This phase is called systole.

The Heart

Blood Pressure When you take your blood pressure, you always get 2

numbers

The systolic pressure it he higher number and

indicate the pressure caused by the contraction of the

heart

The diastolic pressure is the pressure between beats.

It is better to have lower blood pressure, within reason

Your Pulse

When taking your pulse, the pulse you feel is the

systole.

An average heart beats around 75 times per

minute.

This number varies depending on age, gender,

physical fitness and physical activity.

Types of circulation.

The heart is a double pump.

There are two circulatory routes which the blood

takes.

The right side is responsible for the pulmonary

circulation.

The left side is responsible for the systemic

circulation.

Circulatory Routes

Pulmonary Circulation This circulation brings blood to and away from the

lungs.

Right side of the heart is responsible for this

circulation.

Blood is pushed out of the heart by the right ventricle

through the pulmonary artery.

The blood then passes through the capillaries and

then returns to the heart through the pulmonary vein.

Systemic Circulation This is the circulation which sends blood out to the

body systems (except the lungs).

The blood is pushed out the of heart by the left ventricle through the aorta.

The aorta splits and sends blood out through different parts of the body.

The blood then gives its oxygen, nutrients and other goodies to the body tissues through the capillaries.

The blood then returns to the heart through the veins.

Blood Vessels

Now that we understand how the heart works and

we know where the blood goes, let’s talk about

the pathways it takes.

There are three types of blood vessels in our

bodies.

Arteries

Veins

Capillaries

Arteries

Arteries are the largest blood vessels in our

bodies

They carry blood from the heart to other parts of

the body.

Their walls are very thick.

This helps them withstand high pressures.

Arteries

Veins

Veins carry blood back to the heart from the body

systems.

They are thinner than arteries.

They also have small valves in them to prevent

the blood from falling back down.

The pressure is lower than in arteries.

Veins

Veins

Capillaries

Capillaries are small vessels which are only 1 cell

thin.

This is the site of gas and nutrient exchange.

They are the bridge between the veins and

arteries.

Where else have we seen capillaries?

Capillaries

Comparing Blood Vessels

Comparing Blood Vessels

Diseases of the Heart

We are going to discuss 5 diseases of the heart

and vessels.

Arteriosclerosis

Atherosclerosis

Angina

Heart attack

Stroke

Arteriosclerosis This is a condition where the arteries thicken and

become harder.

This causes them to be less flexible. Less flexible means that it puts more pressure on the heart.

This is caused by age, smoking, bad diet, drugs and a poor lifestyle

There are currently no proven medical treatments for this condition as of yet.

Atherosclerosis

This conditions is caused by a build up of plaque

inside the arteries.

These plaques are caused by too much fat and

cholesterol in an individuals diet.

Treatments are improved diet and exercise.

There are some medications which can be taken,

but exercise and diet at the first to be tried.

Atherosclerosis

Angina This is also referred to as angina pectoris.

This is a sharp chest pain.

This is caused by ischemia to the heart, which means a lack of oxygen to the heart.

This is caused by a blockage of the coronary artery, meaning atherosclerosis of the arteries around the heart.

Treatments include nitroglycerin, a strong vasodialator.

Angina Treatments include nitroglycerin, a strong

vasodialator.

A vasodilator is something which dilates, opens up, the blood vessels. This allows more blood and thus more oxygen through.

Since the cause is blockages of the arteries, taking care of those blockages is the first priority.

Again, diet and exercise!

Heart Attack

This is also called a myocardial infarction.

A heart attack is caused by a lack of oxygen to

the heart.

This causes part of the heart to die.

The lack of oxygen is caused by a blockage in the

coronary arteries (the vessels which feed the

heart).

Heart Attack Symptoms of a heart attack are chest pain, numbness

in either arms, nausea, shortness of breathe, etc.

Nitroglycerin can be administered to help prevent

further damage.

Without needing to said, heart attacks can be quite

deadly.

The older you are when you have a heart attack, the

more likely you are to survive.

Heart Attack

Stroke A stroke is caused by a blood vessel in the brain

either bursting or becoming blocked.

This can lead to loss of brain function, ability to move one or more limbs, loss of speech or many other past abilities.

This is due to the lack of oxygen to the brain.

The effects could be permanent or temporary and there is no way to know.

Stroke Risk factors for a stroke are old age, high blood

pressure, diabetes, high cholesterol and smoking.

In this case, the smoking can lead to arteriosclerosis which makes the vessels more prone to breaking.

Prevention is the best defense against strokes.

Once a patient is cleared of the danger of a stroke, the recovery is a long process.

Stroke

Circulatory System Facts The heart beats around 3 billion times in the

averages person's life.

About 8 million blood cells die in the human body every second, and the same number are born each second.

It takes about 20 seconds for a red blood cell to circle the whole body.

Red blood cells make approximately 250,000 round trips of the body.

Red blood cells may live for about 4 months circulating throughout the body.

Blood

Blood is composed of different constituents.

It is also the only liquid tissue in the body.

A man’s body contains approximately 5-6 L of

blood and a woman’s contains 4-5 L.

Although it seems like a homogeneous mixture,

blood is a solution of components suspended in a

liquid.

Blood after centrifugation

Plasma

The liquid component of the blood.

It is 90% water in which has substances

dissolved into it such as:

Hormones

Nutrients

Antibodies

Waste

It is used for transportations of substances.

Blood Plasma

Blood Constituents

Red Blood Cells are red-coloured cells in the form

of a biconcave disk.

They have no nucleus and very few organelles.

There are about 4-6 billion per mL

They responsible for carrying oxygen through the

use of hemoglobin.

Red Blood Cells

Blood Constituents

White blood cells are transparent cells.

There about 4-11 million per mL of blood.

Their role in the body is for our immune system.

They seek out and attack intruders in our bodies.

Types of White Blood Cells

Blood Constituents

Platelets are irregular cell fragments.

There are between 150-400 million per mL of

blood.

They help in blood clotting.

With a low platelet count, one could bleed to

death from a simple paper cut.

Platelets

Blood Types Humans have 4 different blood types.

A

B

AB

O

The blood type is determined by surface proteins on

the red blood cells.

There is also one other substance on their surface

The Rh factor

Rh Factor

The Rh factor is known as the rhesus factor

because it was first discovered on the red blood

of rhesus monkeys, also known as macaques.

Surface Proteins

There are proteins on the surface of the red blood

cells.

The red blood cells are what determine an

individuals blood type.

There are three different surface proteins

A

B

Rh

What’s your blood type?

Blood Type A+ A- B+ B- AB+ AB- O+ O-

Su

rface p

rote

in

A X X X X

B X X X X

Rh X X X X

Blood Types in Quebec

A 42%

B 9%

AB 3%

O 46%

Distribution of types A, B, AB and O

Rh Negati

ve 15%

Rh Positi

ve 85%

Distribition of Rh Positive and Rh

Negative

Distribution of the Eight Blood Types

in Quebec

O+ 39%

A+ 36%

B+ 7%

AB+ 3%

O- 7%

A- 6%

B- 3%

AB- 1%

Distribution of the Eight Blood Types

Blood Transfusions

A blood transfusion entails the injection of blood

into a person.

A donor is defined as the person who gives blood

for the purpose of a transfusion

A recipient is a person who receives blood from a

transfusion

Blood Transfusions

Before the discovery of blood types in 1902,

many transfusions resulted in the death of the

recipient.

We are well aware of the rules of blood

transfusion.

What do you think this rule is?

The Blood Rule

Remember the surface proteins on the red blood

cells.

Those are the key to safe blood transfusions.

To safely receive blood, you must not receive

something you don’t already have.

You cannot receive something which you don’t

have!

Blood Compatibility Donor

O- O+ A- A+ B- B+ AB- AB+

Recip

ien

t

O- X

O+ X X

A- X X

A+ X X X X

B- X X

B+ X X X X

AB- X X X X

AB+ X X X X X X X X

Blood Compatibility Remember, way for a blood transfusion to work

safely the recipient must not receive something which they do not have.

If you are blood type A-, you can’t receive B or +.

This means that O-, which is “empty” is the universal donor.

AB+ is the universal recipient because it already has everything.