Download The heart is protected by rib cage

The mammalian heart
Heart
• locate between two
lungs
• made of cardiac
muscle contracts and relaxes
continuously to
provide (pumping
force)
• protected by
pericardium and rib
cage
The heart is protected by rib cage
Heart – External View
Blood
vessel
Coronary
artery
and vein
Cardiac
Muscle
Vertical section of the Heart
Semi-lunar valves
Pulmonary artery
Arteries
To lungs
Aorta
To body
Pulmonary
Veinsveins
Vena Veins
cava
Left
auricle
bicuspid
valve
Right
auricle
tricuspid valve
septum
Left
Right
ventricle
ventricle
Valve – deoxygenated
prevent back flow of
blood from
blood
……………… toblood
……………..
oxygenated
Oxygenated
blood
Higher oxygen
concentration
Full of Oxygen 
Lower carbon
dioxide
concentration
Deoxygenated
blood
Lower oxygen
concentration
Full of carbon dioxide 
Higher carbon
dioxide
concentration
The cardiac cycle (the sequence of events
that takes place in one
heart beat)
The heart beats as the cardiac
muscles in its wall contracts
(systole) and relaxes (diastole).
Auricle
Ventricle
0
0.2
0.4
0.6
0.8s
Auricle
Ventricle
0
0.2
0.4
0.6
0.8s
 Auricular systole (0 –0.1s)
contraction of the two auricles,
squeezing blood into the ventricles
AV valves (open), semi-lunar valves (close)
Auricle
Ventricle
0
0.2
0.4
0.6
0.8s
 Ventricular systole (0.1 –0.4s)
contraction of the two ventricles,
forcing blood out of the ventricles into the
arteries
AV valves (close), semi-lunar valves (open)
Auricle
Ventricle
0
0.2
0.4
0.6
0.8s
 Diastole ( 0.4 - 0.8s )
all four chambers relax, allowing
blood to flow into the auricles again.
AV valves (open), semi-lunar valves (close)
Changes in blood pressure in the heart during
one cardiac cycle.
Heart beat rate
=
P(V) > P (A)
60 / 0.8 = 75 beats / min
P(V) < P (A)
bicuspid
valve
close
bicuspid
valve open
1st heat
sound
Heart attack
fatty
substances
Fatty substances in blood
cover the inner wall of arteries
Normal
artery
Artery with
fatty deposits
blood flow
restricted
Formation of blood clot
(artery blocked by blood clot)
Plaque is formed and the
arteries become narrower
This reduce the amount of
blood flowing
Heart attack
Same parts of heart muscle get
too little nutrients and oxygen
Heart beat is upset
heart
HEART ATTACK
if coronary artery
is blocked
damaged
heart muscle