Transcript The Circulatory System

The Circulatory System
Lesson Objectives
To have basic knowledge of the structure of the heart and the production of the
heart beat
Be familiar with locating and recording the pulse
Be familiar with the terms blood pressure and know what pressure points are
To know the function and role of the blood
Components of the Circulatory
System
There are three components of the Circulatory
system. They are:
Oxygenated blood carried through
The Heart
Deoxygenated blood carried through
Can you identify the chambers and blood vessels of the heart correctly?
Aorta
Pulmonary
Artery
Vena Cava
Right
Atrium
Right
Ventricle
Pulmonary
Vein
Left
Atrium
Left
Ventricle
Path of blood through the heart
Blood enters the heart via the Vena
Cava and the Pulmonary Vein and
fills the Right Atrium and Left
Atrium. Both Atria contract,
squeezing the blood and pushing it
down in the the Ventricles below
The blood flows through in to the
Right Ventricle and Left Ventricle.
As the blood fills both Ventricles the
muscular walls contract.
The contractions of the atria and the ventricles
are responsible for the heart beating
Blood is forced up in to the
Pulmonary Artery and the Aorta.
The blood in the Pulmonary Artery is
delivered to the Lungs to be
oxygenated. Blood in the Aorta is
then delivered to the rest of the body.
Blood Vessels
Oxygenated blood is carried
in the Arteries and arterioles
Deoxygenated blood is carried in
the venules and veins
Composition of Blood
Red Blood Cells are
used to deliver oxygen
to the muscles
BLOOD
Plasma mainly contains
water. The liquid helps to
transport protein, glucose
and waste products
White Blood Cells form
part of the body’s
immune system. They
help to fight infection.
Platelets help to clot
the blood. When the
skin is wounded they
stick together to cover
the wound.
Functions of Blood
Delivers oxygen to the muscles
Forms part of the body’s immune system
Takes CO2 to the lungs to be exhaled
Used for Homeostasis
Delivers valuable nutrients and glucose to the muscles
Helps to remove waste products
Blood Pressure
BLOOD PRESSURE
As blood travels around the body in the blood vessels it is constantly placed under pressure. The
massive force exerted by the left ventricle contracting creates the largest amount of pressure in the
Aorta. As the blood travels from the arteries to the veins the pressure of the blood decreases.
PRESSURE POINTS
These are areas in the body where
pressure can be measured. Blood
pressure is usually measured at the
Brachial Artery (under bicep
tendon) in the upper arm. An
inflatable cuff is wrapped around
the arm and is pumped up until the
blood stops flowing. A pressure
reading is taken at that point. The
cuff in then deflated and when the
blood starts to flow again another
reading of pressure is taken.
Ok Mrs Smith
your blood
pressure is 110
70
READINGS
The two readings taken for
blood pressure represent the
systolic and diastolic pressure.
Systolic is the pressure created
by the heart contracting and
the diastolic is when the heart
is in its relaxation phase.
The pressures are given as two
numbers.
Average
adult
120
80
(Systolic)
(Diastolic)
Heart Rate
How is the heart rate
measured?
The heart rate can be measured
at many points in the body.
Usually the HR can be taken at
the Radial artery (wrist) or at the
Carotid Artery (neck). Each
beat can be felt as a pulse.
Stroke Volume and Cardiac
Output
Cardiac Output
Stroke Volume x Heart Rate
As we exercise, take running for
example, the cardiac output
increases. This is because the
stroke volume and the heart rate
increase. Why do you think they
need to increase?
Homeostasis (body temperature regulation)
Blood helps to regulate body
temperature by the blood vessels
moving closer to the skin or further
away depending on whether the
body is hot or cold. In hot weather
or whilst exercising the blood
vessels experience a process called
Vasodilation. Blood vessels move
closer to the skin surface to allow
the heat to radiate from the skin.
Sweating is also included within
this process. Vasoconstriction is
the opposite effect where the blood
vessels move away from the skin
when the body is cold.