Download INTRODUCTION TO SPORT SCIENCE

INTRODUCTION TO SPORT
SCIENCE
Class 2 :
Heart Rate
Contents
1) Theory (15min)
2) Practical (25 min)
Heart: Location
Centre of the thoraxic cavity
Flanked by the lungs
Heart Chambers
Superior
vena cava
Aorta
Pulmonary trunk
Left atrium
Right atrium
Left ventricle
Right ventricle
Inferior vena cava
Intraventricular septum
Heart
Atrium
Superior vena cava
Aorta
Left lung
Pulmonary trunk
Ventricle
Apex
Diaphragm
Ventricles
 “Power-pack” of the heart
 Thick muscle - provides the




pumping force for the circulatory
system
Both ventricles contract together
100% of blood from R ventricle
goes to the lungs where it is
oxygenated
Returned to L atria (receptacle)
and flows to L ventricle
Pumped from L ventricle to the rest
of the body
Heart Valves
 Blood flows through the heart in one
direction
 One way traffic is enforced by 4 heart
valves
1. Atrioventricular (AV) valves
2. Semilunar valves
 Opening and closing of valves is a
passive process resulting from pressure
differences across the valves
Atrioventricular Valves
 Located between the atrium
and ventricle in each half of the
heart
 Prevent backflow into atria
when the ventricles contract
 Right AV valve - tricuspid valve
 Left AV valve - bicuspid (mitral)
valve
 Chordae tendineae anchor the
cusps to the papillary muscles
protruding from the ventricle
walls
 Papillary muscles do not open or close the valves - act only to
limit the valves movements and prevent them from being
everted
Opening the AV Valves
 Blood returning the the heart fills the atria
 This puts pressure against the AV valves
 The AV valves are forced open
Closing the AV Valves
 Ventricles contract and force blood against
the cusps of the AV valves, causing them
to close
 Papillary muscles contract and chordae
tendineae tighten preventing valve flaps
from everting into atria
Semilunar Valves
 Pulmonary valve - opening
of the right ventricle into the
pulmonary trunk
 Aortic valve - opening of the
left ventricle into the aorta
 Prevent backflow into the
ventricles
Opening Semilunar Valves
When the ventricles contract the
pressure inside rises
When the pressure inside the
ventricles is greater than the
pressure in the aorta and
pulmonary artery the semilunar
valves are forced open and the
cusps are flattened against the
arterial walls and blood flows past
Closing Semilunar Valves
 When the ventricles relax the pressure inside
falls
 Blood flow back from the arteries
 Fills the cusps of the valves forcing them the
close
Aortic Stenosis
 Disease can damage the
aortic valve
 Unable to open fully during
contraction of the left ventricle
 Causes an obstruction to
blood flow from the left
ventricle to the aorta
 Results in a compensatory
increase in the thickness of
the left ventricle forcing the
heart to work harder
Systemic Circulation
 Oxygen rich blood is
pumped from the L atrium
 L ventricle  aorta to the
organs and tissues of the
body (except the lungs) and
then to the R atrium
 Transfer of gases, nutrients
and waste products occurs
in the capillary beds
Heart Rate
 Number of times that the heart
beats each min (beats/min)
 Usually between 60 and 80
beats/min in a healthy individual
Heart Rate Determination
 You can feel a pulse in an artery that
lies close to the body surface by
compressing the artery against firm
tissue
 Use your two index
finder to locate the
pulse in your radial
artery
Heart Rate Determination
 Count the number of pulses in 10
seconds and multiply by 6 to calculate
the heart rate per minute
 Repeat this 3 times
 Select a partner and
calculate his/her
heart rate per
minute
Heart Rate Determination: Questions
 Draw a histogram to illustrate the heart rate of
each member of the class
 What is the average heart rate of the class ?
 What is the lowest heart rate in the class?
 What is the highest heart rate in the class?
 What is the median heart rate in the class?
 What is the mode heart rate in the class?
 What does the mode, median and mean tell
you about the distribution of heart rates in the
class
What is your Estimated Maximal
Heart Rate?
 Calculated by subtracting your age
from 220
220-age
 Calculate your estimated maximal
heart rate?
Breathing Rate
 Number of times that an individual
breaths per min (breaths/min)
 Usually between 12-16 breaths/min
in a healthy individual
Breathing Rate Determination
 Place your hand on your breastbone
(sternum) and count the number of
inhalations (chest expands) in10
seconds
 Multiply by 6 to calculate the
breathing rate per minute
 Repeat this 3 times
Breathing Rate Determination:
Questions
 Draw a histogram to illustrate the breathing
rate of each member of the class
 What is the average breathing rate of the
class ?
 What is the lowest breathing rate in the
class?
 What is the highest breathing rate in the
class?