Download Heart and Circulation PPT File

The Circulatory System
&
the anatomy of the heart
The circulatory system
• The link between all other body systems
– the cells inside the body and the environment
outside the body
• The body’s transport system – blood is
the medium
Functions of the CV system
• Transports/carries materials such as
food and oxygen to the cells
• Removes wastes from the cells (CO2
etc)
• Role in protection of the body/immunity
The Heart
• A pump that pushes blood around the body
• Located in the mediastinum (between the 2
lungs – slightly more on the left)
• About the size of closed human fist
• Enclosed by a membrane – pericardium (holds
the heart in place, but also allows it to move as
it beats, prevents it from overstretching)
• Wall of the heart made up of a special type of
muscle – Cardiac muscle.
The chambers
• The heart consists of four muscular
chambers.
• The two on the LHS are separated
from the two on the right by the
septum.
• The upper chambers - the atria –
receive blood.
• The lower chambers - the ventricles –
are the pumping chambers.
The chambers
Left
atrium
Right atrium
Septum
Right ventricle
Left
ventricle
The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)
Exterior view of the heart
Aorta
Superior
vena cava
Right atrium
Pulmonary
artery
Left atrium
Pulmonary
vein
Right
ventricle
Inferior
vena cava
Left
ventricle
Image created by Patrick Lynch
Section through the heart
Superior vena
cava
Pulmonary artery
Aorta
Pulmonary vein
Left atrium
Right atrium
Bicuspid valve
Semilunar valve
Tricuspid valve
Septum
Inferior vena cava
Left ventricle
Right ventricle
The Miles Kelly Art library, Wellcome Images
•
•
•
•
The Valves
The direction of the blood flow is
controlled by four valves.
The atrioventricular valves are held
in position by strong tendons, the
chordae tendinae (tendineae).
The other valves are the semi-lunar
valves
The heart sounds – “lubb dubb” –
result from the valves snapping
shut.
The valves
Pulmonic
semilunar
valve
Tricuspid
atrioventricular
valve
Chordae
tendinae
Aortic
semilunar
valve
Bicuspid
atrioventricular
valve (mitral
valve)
The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)
The blood vessels
Superior vena
cava
Pulmonary
artery
Aorta
Pulmonary
vein
Inferior vena
cava
The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)
The blood vessels
Carries
From
To
Vena cava
Deoxygenated
blood
The body
Right
atrium
Pulmonary
artery
Deoxygenated
blood
Right
ventricle
The lungs
Pulmonary
vein
Oxygenated
blood
The lungs
Left atrium
Aorta
Oxygenated
blood
Left
ventricle
The body
Blood circulation through the heart
From the
upper
body
To the
lungs
To the
body
From the
lungs
From the
lungs
From the
lower
body
The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)
Heart Beat
The heart contains specialised conductive
tissue which regulates the heartbeat.
• The sinoatrial node (SA node or
pacemaker) is a cluster of specialised
cardiac cells in the wall of the right atrium
which initiates the heartbeat.
• The atrioventricular node (AV node) is the
secondary pacemaker which regulates the
beating of the ventricles.
Conductive tissue
Sinoatrial (SA)
node – the
pacemaker
Atrioventricular
(AV) node
Perkinje fibres
The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)
The circulatory system
The blood vessels
& circulation
Blood Vessels Basics
• Arteries – carry blood away from the heart
• Veins – carry blood back to the heart
• Capillaries – small vessels where exchange
of gases, nutrients and wastes takes place
Circulation
Double circulation
Humans, like all mammals, have a
double circulation:
• The systemic circulation
and
• The pulmonary circulation.
• This can be seen because there is
two sides of the heart – each
involved in a different circulation
• Right side of the heart is involved in
blood to and from the lungs
(pulmonary circulation)
• Left side of the heart is involved in
blood to and from everywhere in the
body (excluding the lungs)
(systemic circulation)
The pulmonary circulation
• The pulmonary circulation
takes deoxygenated blood from
the right ventricle to the lungs
and returns oxygenated blood
to the left atrium.
• The right ventricle is the pump
for the pulmonary circulation.
Pulmonary circulation
LUNGS
Pulmonary
artery
Pulmonary circulation
Left
atrium
HEART
Right
ventricle
Pulmonary
vein
The systemic circulation
• The systemic circulation
takes oxygenated blood from the
left ventricle to all the tissues of
the body and returns
deoxygenated blood to the right
atrium.
• The left ventricle is the pump for
the systemic circulation.
Systemic circulation
Right
atrium
HEART
Left ventricle
Vena
cava
Aorta
Systemic circulation
ALL PARTS
OF THE
BODY
Both together = Double circulation
LUNGS
Pulmonary circulation
HEART
Systemic circulation
OTHER
PARTS
OF THE
BODY
• Therefore blood passes through the heart
twice during one complete circuit of the CV
system
• This double circulation has the advantage
that after blood goes through the lungs
and losing much of its pressure, the heart
pumps the blood again before going to the
body cells
• This means blood is kept moving rapidly
and therefore the cells get the
requirements they need
Major arteries
Carotid A
Subclavian A
Aorta
HEART
Celiac A
Mesenteric A
Renal A
Common
iliac A
Femoral A
The Sourcebook of Medical Illustration (The
Parthenon Publishing Group, P. Cull, ed., 1989)
Major veins
Jugular V
Subclavian V
Superior vena
cava
HEART
Inferior vena
cava
Hepatic V
Renal V
Common
iliac V
The Sourcebook of Medical Illustration (The Parthenon Publishing Group, P. Cull, ed., 1989)
Stop here.
The blood vessels
• Arteries - muscular blood
vessels that carry blood away
from the heart.
• Arterioles – small arteries that
direct blood flow to various
tissues.
• Capillaries – microscopic blood
vessels that connect arterioles
and venules. They enable the
exchange of substances
between blood and
surrounding tissues.
• Venules – small veins.
• Veins - blood vessels that carry
blood toward the heart.
Arteries, veins and capillaries
Capillary
bed
Vein
Arteriole
Venule
Artery
The Miles Kelly Art library, Wellcome Images
Blood vessels - structure
Tunica interna
(endothelium)
Tunica externa
Tunica media
The Miles Kelly Art library, Wellcome Images
• Arteries & veins have three layers (the tunicae) – the
tunica externa, tunica media & tunica interna
Blood vessels - structure
Arteries
Capillaries Veins
Tunica
interna
Present
Present
Tunica
media
Well
None
developed
Relatively
thin
Tunica
externa
Relatively
thin
Well
developed
None
Present
Arteries and veins
VEIN
ARTERY
G. Meyer – ANHB, UWA
Notice the
relatively thin
wall and large
lumen.
Notice the
relatively thick,
muscular wall
and small lumen.
Veins contain valves to prevent
the back flow of blood
Valve
closed
Valve
open
Section through a vein showing a valve
Valve
The Miles Kelly Art library, Wellcome Images
Capillaries are where the exchange of materials
takes place and consist of one layer of cells only
The Miles Kelly Art library, Wellcome Images
A capillary bed
Capillaries
Artery
Vein
Jean Wade and Linda Sharp, Wellcome Images
Capillaries
Capillary
G. Meyer – ANHB, UWA
L. Slomianka – ANHB, UWA
Study Guide
Read:
• Our Human Species
Chapter 10, sections 4-5, 8-13
Complete:
• Workbook
Topic 7, The heart and circulation