Transcript 1. Repiration Lesson SJW

Function:
1. Delivery of sufficient oxygen to our muscles to produce the energy which fuels
muscle contraction.
2. Carbon Dioxide produced by the muscles must be cleared and removed from
the body
1. Pulmonary Ventilation – the breathing of air into and out of the lungs.
2. External Respiration – exchange of oxygen and carbon dioxide between
the lungs and blood.
3. Internal Respiration – the exchange of oxygen and carbon dioxide
between the blood and the muscle tissues.
Link between Cardiovascular and
Respiratory Systems
The Vascular System
Includes the blood and the
blood vessels.
Transports oxygen around
the body’s tissues and
carbon dioxide to the lungs
The Respiratory
System
Ensures an adequate supply
of oxygen is available to meet
demands
Removes carbon dioxide
The Heart
Acts as a dual pump
Left side pumps oxygen-rich blood around to the body’s tissues so
they can function properly
The right side pumps blood low in oxygen but high in carbon
dioxide around to the lungs – carbon dioxide can be expired and
blood re-oxygenated
Draw Fig. 3.02 Page 39
Put the following structures in order to show the route
of atmospheric air to the site where gaseous
exchange takes place:
nose/trachea, alveolus, larynx, pharynx, oral cavity,
alveoli sacs, left and right bronchi, nasal cavity, lungs,
bronchioles, mouth.
Inspiration
•Atmospheric pressure
outside forces air into the
lungs
•Air in lungs is at lower
pressure than air in
atmosphere
Ribcage moves
upwards and
outwards
Diaphragm is
pulled down flat
DURING EXERCISE
the scalenes, sternocleidomastoid, pectoralis minor muscles contract
lungs have even bigger volume - more air forced in
Lung
Expiration
Ribcage moves
inwards and down
– falls in
The diaphragm
relaxes and returns
to its resting
dome shape
DURING EXERCISE
internal intercostal and abdominal muscles contract, air forced out more rapidly
Inspiration
Expiration
External Intercostals
contract
External Intercostals
relax
Ribcage moves
upwards and
outwards
Ribcage moves
downwards and
inwards
Diaphragm contracts
downwards and
flattens
Diaphragm relaxes
back to its dome shape
Increases the size of
the thoracic cavity
Decreases the size of
the thoracic cavity
Decreases air
pressure in lungs
Increases air pressure
in lungs
Air drawn into lungs
Air forced out of lungs
5 Easy Steps to learn the mechanics of
respiration:
1. Muscles – actively contract or passively relax to
cause:
2. Movement – of the ribs and sternum and abdomen
which causes:
3. Thoracic cavity volume – to either increase or
decrease which in turn causes:
4. Lung air pressure – to either increase or decrease
which causes:
5. Inspiration or expiration – air breathed in or out.
Exam Question


June 10
Explain the mechanics of breathing which
allow a performer to fill the lungs with air
during exercise.
Mark Scheme

June 10
A. Diaphragm/intercostal muscles contract/ flattens;
B. Lungs/ribs also pulled upwards and outwards;
C. Lungs attached to pleural membranes;
D. Volume/size of chest/thoracic cavity/lungs increases;
E. Reducing pressure within lungs;
F. Air sucked in;
G. During exercise other muscles – strernocleidomastoid
/ scalenes and pectoralis minor increase action;
Figure 1 shows the spirometer reading of an athlete.
(i)
Which ‘lung volume’ is represented by the letter B.
(1 mark)
B = Inspiratory reserve (volume)
(ii) What would be the effect on the spirometer trace for
lung volume A of a period of continuous running? (2 marks)
A. Increase in tidal volume/larger/higher proportion
B. More frequent peaks/closer together
LUNG VOLUMES

Lung volumes are defined as :

TLC





= total lung capacity
= total volume of air in the
lungs following
maximum inspiration
VC
= vital capacity
= maximum volume of air
that can be forcibly
expired following
maximum inspiration
TV
= tidal volume
= volume of air inspired or
expired per breath
IRV = inspiratory reserve volume
= volume of air that can be forcibly inspired above resting tidal volume
ERV = expiratory reserve volume
= volume of air that can be forcibly expired above resting tidal volume
RV
= residual volume
= volume of air remaining in the lungs after maximal expiration
Lung Capacities
Lung capacities result from adding two or
more lung volumes together.
 Vital capacity is the sum of Inspiratory
reserve volume, tidal volume and expiratory
reserve volume (VC=IRV+TV+ERV)
 This is typically 5000ml of air
Lung volumes can be measured using a
Spirometer, which identifies lung function.
- Use show me boards for Spirometer trace

Lung Volume Question


While running, a performer will experience changes in
lung volumes.
Complete Table 3 below to show how the tidal volume,
inspiratory reserve volume and expiratory reserve
volume change during exercise.
Mark Scheme



A. Tidal volume – increases
B. Inspiratory reserve volume – decreases
C. Expiratory reserve volume – decreases
Minute Ventilation

Minute ventilation is the volume of air
breathed in or out per minute. It is calculated
by multiplying a persons Tidal Volume (TV)
by the number of times they breathe per
minute (breathing rate, f)

VE =TV x Breathing rate (f)
Calculate numbers on show-me board

Lung volume or
capacity
Definition
Average
value at
rest (litres)
Average
value
during
exercise
Change during
exercise
Tidal Volume
Volume of air
breathed in or out
per breath
0.5 / 500ml
2.8L
Increase
Inspiratory Reserve
Volume (IRV)
Volume of air that
can be forcibly
inspired after a
normal breath
3.1 L
2L
Decrease
Expiratory Reserve
Volume (ERV)
Volume of air that
can be forcibly
expired after a
normal breath
1.0 L
1.2L
Slight decrease
Lung volume or capacity
Definition
Average
value at rest
(litres)
Average
value during
exercise
Change
during
exercise
Residual Volume
Volume of air that
remains in the lungs
after maximum
expiration
1.2 L
1.2
Remains the
same
Vital Capacity
Volume of air forcibly
expired after
maximum inspiration
in one breath
4.8 L
4.8
Remains the
same
Minute Ventilation
Volume of air breathed
in and out per minute
6L
110
Increase
Total Lung Capacity
Vital capacity +
residual volume.
6L
6
Remains the
same
Frequency
Amounts of breaths
per minute
12 - 15
Increases
Minute Ventilation = number of breaths per minute x tidal volume
= 12 x 0.5 OR 15 x 0.5
= BETWEEN 6 litres and 7.5 litres
Ventilation during exercise



What will happen to breathing during
exercise? Why?
During exercise, both the rate (frequency)
and depth (tidal volume) of breathing
Increases in direct proportion to the intensity
of the activity.
This is to satisfy the demand by the working
muscles for oxygen and to remove the
carbon dioxide and lactic acid that is
produced.
Minute Ventilation during exercise

Sub-Maximal exercise – low intensity


Sporting examples…
Maximal exercise – high intensity

Sporting examples…
d
e
e
f
f
a = anticipatory rise – due to emotional excitement & release of adrenaline.
b = sharp rise – increase in CO2 & lactic acid. Muscle movement detected by proprioceptors. Send messages
to respiratory centre in medulla of brain to increase the rate and depth of breathing.
c & d = slower increase/steady state – plateau due to O2 demand being equal to the O2 supply.
e = rapid decline– O2 demand drops suddenly.
f = slower recovery as body returns to resting levels.
CHANGES IN MINUTE VENTILATION
WITH EXERCISE
Exam tips

In the exam, you may be required to explain
the patterns of the two graphs, so make sure
you understand them.
Prep Task
Gaseous exchange:
 Read pages 46-49
 Name four factors that influence the rate of
gaseous diffusion across the respiratory
membrane in the alveoli.
Learning Outcomes
1. Explain how carbon dioxide and
oxygen are exchanged
2. Explain / describe how oxygen and
carbon dioxide is transported around
the body
•Partial pressure is a term often used when describing the gaseous
exchange process.
•All gasses exert a pressure.
•Oxygen makes up only a small part of air (21%) so it therefore exerts
a partial pressure.
•Gases flow from an area of high pressure to an area of low pressure.
•As Oxygen moves from the alveoli the partial pressure of oxygen in
the blood and then the muscle needs to be successively lower.
•Partial pressure of oxygen in the alveoli is higher than the partial
pressure of oxygen in the blood because oxygen has been removed
from the working muscles, so its concentration in the blood is lower.
External
Respiration
Internal
Respiration
Where?
Alveolar-capillary
membrane between alveoli
air and blood in alveolar
capillaries.
Tissue-capillary membrane,
between the blood in the
capillaries and the tissue
(muscle) cell walls.
Movement
O2 in alveoli diffuses to
blood;
CO2 in blood diffuses to
alveoli.
O2 in blood diffuses into
tissue;
CO2 in tissues diffuses into
blood.
Why? – O2
PP of O2 in alveoli higher
than PP of O2 in the blood
so the O2 diffuses to the
blood.
PP of O2 in blood is higher
than the PP of O2 in the
tissue so the O2 diffuses
into the Myoglobin within
tissues.
Why – CO2
PP of CO2 in the blood is
higher than the PP of CO2
in the alveoli so CO2
diffuses into the alveoli.
PP of CO2 in the tissue is
higher than the PP of CO2 in
the blood so CO2 diffuses
into the capillary blood.





Increases in Lactic Acid
Increases in CO2
Increases in blood and muscle temperature
Decreases in pH thus acidity levels increase.
These changes mean that the body needs
oxygen quickly.
Features that Facilitate Diffusion at the
Alveolar
1. Alveolar membrane is very thin = short diffusion
distance between the air in alveoli and the blood
2. Numerous (millions) of alveoli creates a VERY LARGE
surface area for diffusion to take place
3. Alveoli are surrounded by a vast (large) network of
capillaries = huge surface area for diffusion
4. The diameter of the capillaries is slightly narrower than
the area of a red blood cell. This forces the blood flow
slowly in single file.
The reaction between 02 and Hb is easily reversible and is
represented by the oxy-haemoglobin dissociation curve
Rest
The oxy-haemoglobin dissociation curve represents the amount
of Hb saturated with 02 as it passes through areas of the body
that have very different partial pressures of 02 (P02)
During exercise muscles
need more oxygen so the
dissociation (release) of
oxygen from Hb happens
more readily
This is known as the
Bohr effect and frees
up more oxygen = used
by working muscles
Dissociation
curve shifts to
the RIGHT
This happens because:
• CO2 and lactic acid
production
• =acidity of blood (pH)
• blood & muscle temp
(energy released as heat from
muscle contraction)
•Factors shifting the dissociation curve to the right are:
•1. Increase in blood and muscle temperature
•2. Decreases in PP oxygen within muscle increasing the oxygen diffusion
gradient.
•3. Increase in PP of carbon dioxide increasing carbon dioxide gradient.
•4. Bohr effect – increase in acidity (lower pH)
•These factors increase during exercise. The effect is that the working
muscles:
•Generate more heat when working
•Use more oxygen to provide energy, lowering the PP oxygen
•Produce greater carbon dioxide as a by-product
•Increase lactic acid levels which increase muscle/blood acidity
•Collectively all four factors increases the dissociation of oxygen from
haemoglobin that increases the supply of oxygen to the working muscles.
•Difference between any two pressures = concentration/diffusion gradient.
•The steeper the gradient the faster diffusion is.
•Oxygen diffuses from the alveoli into the blood until the pressure is equal in
both.
•Movement of carbon dioxide occurs in the same way but in the reverse order,
from the muscle to the blood to the alveoli.
Partial pressure
Capillary
blood
Direction of
diffusion (high to low
pp)
Muscle
tissue
Diffusion gradient
O2 resting
100
40
60
O2 during
exercise
100
<5
95
CO2 resting
40
45
6
CO2 during
exercise
40
80
40
AT REST
Inspiratory centre is responsible for rhythmic cycle of inspiration and expiration
to produce a respiratory rate of 12-15 breaths a minute.
Impulses are sent via:
Phrenic nerves to the diaphram
Intercostal nerves to the external intercostals.
When stimulated these muscles contract, increasing the volume of the thoracic
cavity, causing inspiration (active)
When their stimulation stops, the muscles relax, decreasing the volume of
thoracic cavity, causing expiration (passive)
The expiratory centre is inactive during quiet/resting breathing. It is passive as
a result of the relaxation of the diaphragm and external intercostals.
DURING EXERCISE
Pulmonary ventilation increases during exercise, which increases both the
depth and rate of breathing. This is regulated by:
1. The Inspiratory Centre which:
(a) increases the stimulation of the diaphragm and external intercostals
(b) stimulates additional inspiratory muscles for inspiration, the
sternocleidmastoids, scalens and pectoralis minor, which increase the
force of contraction and therefore the depth of inspiration.
2. The expiratory Centre which:
(a) stimulates the expiratory muscles, internal intercostals, rectus
abdominus and obliques, causing a forced expiration which reduces the
duration of inspiration.
(b) the inspiratory centre immediately stimulates the inspiratory muscles
to inspire, which results in an increase in the rate of breathing.
Hering-Breuer Reflex
•
Expiratory centre acts as a safety mechanism in the lungs to ensure they
are never over inflated.
•
Stretch receptors in the lungs detect when the depth of breathing
increases and stimulate the RCC to inhibit the inspiratory centre and
stimulate the expiratory muscles.
Chemoreceptors
(detect changes
in blood acidity)
Barorecep
tors
(detect
changes in
blood
pressure)
Stretch receptors (prevent over
inflation of the lungs; if these start
to get excessively stretched they
send impulses to the expiratory
centre to induce expiration (Hering
Breur reflex))
Thermoreceptors
Proprireceptors
(detect movement)
Expiratory Centre
Respiratory Centre
Inspiratory Centre
(Medulla Oblongata)
Phrenic
Phrenic nerve
nerve
Diaphram and
external
intercostals
Increase
breathing
rate
Intercostal nerve
Abdominals and
internal
intercostals
Increase
expiration
Effects of Altitude on the Respiratory System
At high altitude (above 1500m) the PP of oxygen in the atmospheric air is
significantly reduced.
1. Decreases pO2 in alveoli – Hypoxia which causes a reduction in the
diffusion gradient thus a decrease in O2 and Hb association.
2. This results in a decreases O2 transport in the blood causing a reduction
in the O2 available to working muscles.
3. It thus decreases VO2 max or aerobic capacity also can increase
breathing which leads to hyperventilation. Can also lead to dehydration
quicker.
Long term affect – increases in Hb and RBC production which increases
external respiration and O2 transport.
Iron based protein
Similar to Hb
•In the muscle oxygen is transported by myoglobin.
•Myoglobin has a high affinity for oxygen.
•It stores oxygen and transports it from the capillaries to
the mitochondria.
•Mitochondria are the centres in the muscle where aerobic
respiration takes place.
Much
higher
affinity
For 02 than
Hb
(a-vo2 diff)
This represents how much oxygen is actually
extracted and used by the muscles
Measured by:
Analysing the difference in oxygen content of the blood in
the arteries leaving the lungs and that in the mixed venous
blood returning to the lungs