P5/ M2
The Heart
• Muscular pump, about the size of a clenched
fist
– Made up of a special muscle called
Myocardium
• This can contract continuously without getting
tired
• Main purpose is to drive blood through the
arteries
– This delivers blood to the working muscles and
other tissues.
Task…
Find a picture of a blank heart (that is suitable to annotate) and
upload it to a blank document.
- Then do some light background research on the different labels of
the heart including…
- Structure of the cardiovascular systemAtria
Ventricles
Bicuspid valve and tricuspid valve
Aortic valve and pulmonary valve
Aorta and vena cava – superior and inferior
Pulmonary vein and pulmonary artery
:
The Heart continued
• The Heart sits in a twin
layered sac known as
the Pericardium
– Filled with pericardial
fluid
• Prevents friction as
your heart beats.
The Heart continued
• The heart wall has 3 layers
–
(Outer)
(middle layer and most of the heart wall)
–
(The inner layer)
 Atria/ Atrium
 Upper chambers of the heart
 Receive blood.
 Right Atrium – receives deoxygenated blood from
the body (Via the Vena Cava)
 Left Atrium – receives oxygenated blood from the
lungs (Via the pulmonary Vein)
• Ventricles
– Lower chambers of the heart
– They have thicker walls and are
stronger
– Job is to pump the blood
– Right Ventricle pumps blood to the
lungs (pulmonary circulation)
– Left ventricle pumps blood to the
body (systemic circulation)
Valves
• Tricuspid Valve
• Bicuspid Valve
– Also known as the mitral valve
• Aortic Valve
• Pulmonary Valve
– All valves make sure that the blood
flows in one direction, and there is no
back flow
• Chordae Tendineae
– Cord like tendons that connect to the
tricuspid and bicuspid valves
• Ensure the valves stay the right way
round and keep the blood flowing in
the same direction.
• The largest vein is
the Vena Cava
– Carries blood
directly into the
heart from the
body
– Superior vena cava
– brings blood from
the upper body
– Inferior Vena Cava
– Brings blood from
the lower body.
Aorta and Vena Cava
• The largest Artery
is the Aorta
– Carries
oxygenated blood
directly out of the
heart to the body
tissues
Pulmonary Circulation
• Pulmonary Artery
– Carries
deoxygenated
blood from the heart
to the lungs.
• It is the only artery
• Pulmonary Vein
– Carries
oxygenated blood
from the lungs to
the heart
• It is the only
vein that carries
oxygenated
blood.
that carries
deoxygenated
blood
The Heart = Double pump
• To describe the flow of blood
around the heart and the body,
you will need to mention that
the heart is made up of two
pumps
– Pulmonary
circulation
• Pumps blood to and from the
lungs
– Systemic circulation
• Pumps blood around the body
Passage of blood flow
 Blood flows into and out of the
heart and around the body in
one direction.
 The heart is split into two
distinct pumps by the Septum.
 This makes sure that the
oxygenated and deoxygenated
blood don’t mix.
 When describing the passage
of blood flow around the heart,
it is best to use a diagram and
start on the right side of the
heart.
The
side of the heart
• Blood enters the heart (when it is relaxed) via the vena cavae,
• It goes into the right atrium
• The right atrium contracts and the blood goes through the tricuspid
valve and into the right ventricle
 The right ventricle contracts and the blood is
pushed out of the heart through the semi lunar
or pulmonary valve and into the pulmonary
artery
 The pulmonary artery carries the blood to the
lungs
 The heart relaxes and the valves close to stop
back flow of the blood
 In the lungs, the blood becomes oxygenated,
and begins it’s journey back to the heart.
The
side of the heart
• The heart is relaxed, and this
allows blood to enter the left
side of the heart from the
pulmonary vein
• It enters the left atrium
• The left atrium contracts and
pushes blood through the
bicuspid valve and into the
left ventricle
•
•
The left ventricle has a very strong muscular wall and contracts very strongly. This
closes the bicuspid valve to prevent backflow, and pushes the blood through the
aortic valve and into the aorta. This is the largest artery and splits taking the blood
to different areas of the body
The heart contracts and the aortic valve closes, preventing back flow of the blood.
Terminology
• Heart rate (H.R.)
– The amount of times the heart beats in a minute.
• Usually measured in beats per minute (b.p.m.)
• Stroke Volume (S.V.)
– The amount of blood leaving the left ventricle in one
beat.
• Normally measure in mililitres
• Cardiac Output
– The amount of blood leaving the heart in one minute
• Normally measured in litres/minute
• Cardiac Output = Stroke Volume x Heart Rate
The Blood Vessels
Introduction
We have a variety of different vessels within the
cardiovascular system to deliver and remove nutrients and
waste products.
Blood in the arteries is bright red, as it is carrying oxygen. It
drops off the oxygen and picks up carbon dioxide as it
moves through the capillaries. By the time it reaches the
veins and venules it is a much darker blue/red colour.
5 main blood vessels
• Arteries
– Arterioles
• Capillaries
– Venules
Carry blood away
from the heart
Where gas
exchange takes place
• Veins
Carry blood back to
the heart
• Arteries are large blood
vessels, that carry blood
away from the heart.
Arteries & Arterioles
•Carry Oxygenated blood
–Apart from the pulmonary artery,
which carries deoxygenated blood to
the lungs to get Oxygen
Arteries & Arterioles
• Small round lumen
• Operate under high pressure
• Arteries don’t contain valves, as
the blood is moving quickly
under high pressure, so there is
no chance of backflow.
Aorta
–Main artery leaving the heart
It soon splits into smaller vessels –
Arterioles
–Arterioles deliver the blood to
the capillaries
Smallest blood vessels
– Found in all cells of the body
Just one cell thick
•
Capillaries
Very thin walls
– Allows oxygen and other nutrients to diffuse through the cell walls.
• Blood flows very slowly through the capillaries so that this can happen
– Effectively in the capillaries, the blood unloads the Oxygen and picks up
carbon dioxide and lactic acid (the waste products of metabolism)
Veins & Venules
Veins & Venules
• Carry blood back to the heart
– Generally working against gravity
• Particularly blood that is going back to the
heart from the legs or arms, as it is below the
heart.
– Valves
• To prevent the blood from flowing back once
the smooth muscle relaxes.
• Prevents pooling, particularly in the legs
Deoxygenated blood
– Apart from pulmonary vein which carries oxygenated
blood from the lungs back to the heart.
Task…
You are going to outline the function and
characteristics of each of the 5 types of
Blood Vessels that serve the circulatory
system…
Including:
- Physical characteristics that classify
each blood vessel.
- What their function is within the
CIRCULATORY system?
- What do they transport?
Followed by a description/
explanation of the
composition of BLOOD
Blood
It is the medium in which all the cells are carried to
transport nutrients and Oxygen (O2) to the cells of the
body.
It carries:
- Oxygen,
Glucose, Proteins, Fats,
Vitamins, Hormones, Enzymes, Platelets,
Carbon Dioxide and Electrolytes.
Plasma: straw
coloured liquid
that all solids
are carried
within.
Made up of 4 components:
-
Red blood cells
White blood cells
Platelets
Plasma
Red blood cells make up 99% of the
population of the blood cells in the
body
They are RED in colour due to
the presence of a protein called
HAEMOGLOBIN and absolutely
loves Oxygen (massive
attraction!)
Cells
They are colourless and
transparent and fewer in
number to red blood cells
(1:700)
They destroy bacteria and
other dangerous organisms…
thus fighting potential
infection.
They become sticky
when in contact with
air to form the initial
stage of repair to
the damaged
tissue…
They act by
stopping blood loss
through clotting
Yet platelets need a substance called
x-Factor 8 to enable them to become
active and do their job/clot.
Structure and
Function of the cardiovascular system
Describe the
Structure of the
cardiovascular system (which you
have to find pictures/ label and
describe):
Heart:
Atria, Ventricles, Bicuspid valve,
Tricuspid valve, Aortic valve,
Pulmonary valve, Aorta, Vena cava –
(superior and inferior), Pulmonary
vein, Pulmonary artery
Blood vessels:
Arteries, Arterioles, Capillaries,
Veins, Venuoles
Examine the cardiovascular
explain
system and
how it
works and how each part of the
system is designed to meet its
function
Function of the cardiovascular system:
1. Delivery of oxygen and nutrients
2. Removal of waste products
3. Thermoregulation (vasodilation and
vasoconstriction of vessels);
4. Function of blood (oxygen transport,
clotting, fighting infection)