2. INTRODUCTION
DEFINITION
History of cardiac cycle
Comparitive physiology of cardiac
cycle btw mammals and humans
EVENTS
DIVISION & DURATION
SUB DIVISIONS
HEART SOUNDS
Recent advances in cardiac cycle
Investigations of cardiac cycle
applied physiology of cardiac cycle
3. History of cardiac cycle
In the 16th centrury,william harvey described the circulation of blood
through the body and demonstrated that the heart acted as a
pump,pushing blood through the veins and arteries.
In the 19th century french physiologist claude bernard and german
physician carl ludwig developed techniquies for measuring the pressur and
volume of blood in the heart.
In 20th century,advances in technology and instrumentation,such as
electrocardiogram(ECG) and the catherization of the heart ,allowed for
even better understanding of cardiac cycle.
These tools made it possible to directly measure the electrical activity of
the heart and the pressure and flow within the heart chambers
4. Comparitive physiology of cardiac
btw mammals and humans
Cardiac cycle is similar in all mammals,including humans,as basic physiological mechanism
is same but some differences are there they are
Heart rate:The heart rate of mammals can vary greatly depending on the species and
individuals,and change to different environment or physiological factors.in humans average
heart is around 70 bpm but vary depend upon age,fitness,and other factors
Cardiac output:cardiac output can vary widely btw mammals and humans.in humans cardiac
output is regulated by autonomic nervous system,which can adjust the heart rate and the
stroke volume.
Ventricle size:The size of ventricles vary btw mammals and human beings,depending upon
size of the heart in larger animals such as horses and elephants ,the ventricles are much
larger compared to small mammals and humans.
Blood pressure:Blood pressure also vary btw mammals and humans .In general blood
pressure is higher in larger mammals and lower in small mammals and humans.
31. Investigations of cardiac cycle
Electrocardigram(ECG):This is a non-invasive test that measures the
electrical acttivity of heart.it is used to identify abnormal
rhythms,conduction delays.
Echocardiogram:This is an ultrasound test that creates image of the heart
to evaluate its structure and functions.It can be used to assess the size
and shape of the heart,and the flow of blood through the heart and blood
vessels.
Cardiac catheterizaion:This is an invasive procedure used to measure
the pressure and blood flow in the heart and blood vessels.
Coronary angiogram:This is a diagnostic test that uses x-rays and a
special dye to visualize the blood flow through the coronary arteries,which
supply the heart with blood.
Sress testing:This involves performing physical exercise or
pharmacological stress(using medication to stimulate the effects of
exercise) used to identify areas of decreased blood flow.
32. Recent advances in cardiac cycle
Advances in medical imaging,such as MRI and CT scans have allowed for
improved visualization of the heart and its blood vessels,providing a better
understanding of the cardiac cycle.
Development of minimally invasive procedures:such as transcatheter
aortic valve replacement and catheter ablation,have become
increasingly common for treatment of heart conditions.
Improved understanding of arrhthmias and irregular heart beats.
Advances in cardiac rehabilitation:a program of exercise and education
for people who have had a heart attack or heart surgery,advances in
tecnology have allowed for the development of new rehabilitation
programs and treatments that can help pt to recover more quickly and
effectively.
33. Applied physiology of cardiac cycle
Some of the key applied physiological aspects of the cardiac cycle events include:
Blood flow:The cardiac cycle events regulate the flow of blood through the heart and into
the arteries.
Pressure regulation:The cardiac cycle events play a crucial role in regulating blood
pressure.
Cardiac output:The cardiac cycle events regulate the cardiac output,Which is the amount
of blood pumped by the heart per minute.The cardiac output is regulated by heart rate and
the stroke volume .The cardiac output can be increased or decreased in response to
change in physiological demand.
Autonomic regulation:The cardiac cycle events are regulated by autonomic nervous
system,which can adjust the heart and stroke volume in response to change in physical
demand.
Ex:During exercise ANS can increase the HR and stroke volume to deliver more blood to
the working muscles.
