RESPIRATION
ACTIVITY 1
Write down as many terms as you can
that are used to describe the respiratory
system
•Bullet point your answers
The air continues into many
branching airways known as
the bronchial tree
The trachea and bronchi
have supporting cartilage
to keep the airways open
Bronchiole walls
contain more
smooth muscle.
The air is moistened,
warmed and filtered as it
flows through these
passageways
The airways from the nasal
cavity through the terminal
bronchioles are called the
conducting zone
The air then reaches the
respiratory zone
The respiratory zone
The respiratory zone
contains alveoli, tiny
thin walled sacs where
gas exchanges occurs.
Terminal
bronchi
Alveoli
Lets now look at the actual site of
diffusion, the respiratory
membrane
ACTIVITY 2
Complete the following worksheets:
1. WS.1
2. Worksheet 5.1
3. Worksheet 5.2
ACTIVITY 3
Highlight the key words within the
following text on IS 1
MECHANICS OF RESPIRATION
DURING EXERCISE
• What muscles are involved?
• Inspiration – SCOM
(sternocleidomastoid), scalenes &
pectoralis minor
• Expiration – internal intercostals
& rectus abdominals / obliques
Sternocleidomastoid (SCOM)
Scalenes
ABDOMINALS
ACTIVITY 4
Highlight the key words on IS 2
Respiratory system – 3 main
processes
• Pulmonary respiration
– The breathing of air into and out of the lungs
• External respiration
– Exchange of O2 and CO2 between the lungs and
the blood
• Internal respiration
– Exchange of O2 and CO2 between the blood and
muscle tissues
RESPIRATORY VOLUMES
AT REST
• Tidal volume (TV)
– Amount of air inhaled and exhaled with each
breath (approx 500ml)
• Frequency (F)
– Rate of breathing
• Minute Ventilation (VE)
– VE = TV X f
• Residual volume (RV)
– Volume of air remaining in the lungs (1200ml)
RESPIRATORY VOLUMES AT
REST (Cont’d)
• Inspiratory reserve volume (IRV)
The additional air that can be inhaled after a normal
tidal breath in. The maximum volume of air that can be
inspired in addition to the tidal volume.
• Expiratory reserve volume (ERV)
The amount of additional air that can be pushed out
after the end expiratory level of normal breathing
*see IS 3
LUNG CAPACITIES
• Inspiratory capacity = IRV + TV
• Expiratory capacity = ERV + TV
• Vital capacity
–Maximal volume of air that can be
expired after maximal inspiration
• Total lung capacity
–Maximal volume of air contained in the
lungs after a maximal inspiration
–TLC = TV + IRV + ERV + RV
Control of breathing
• Respiratory Control Centre (RCC)
regulates breathing.
• Located in the medulla oblongata
• Respiratory muscles – involuntary
neural control
• RCC – 2 areas
–Inspiratory centre
–Expiratory centre
Important terminology
1. Chemoreceptors from within the
carotid arteries send information to
the inspiratory centre on chemical
changes
2. Proprioceptors – muscle movements
3. Thermoreceptors – blood
temperature
4. Baroreceptors – stretch receptors
NEURAL CONTROL DURING
EXERCISE
• Associated muscles (inspiratory centre):
– Sternocleidomastoid
– Scalenes
– Pectoralis minor
• Associated muscles (expiratory centre):
– Internal intercostals
– Rectus abdominus
– Obliques
This is summarised on IS 4
Complete WS2