1.2 The Resiratory System Flashcards
What is the order of correct passage of air ?
Nose,pharynx,larynx,trachea,bronchi,bronchioles,alveoli
What are responsible for the exchange of gases between the lungs and the blood ?
The alveoli
Diffusion
The movement of gas molecules from an area of high concentration or partial pressure to an area of low concentration or partial pressure
How is the structure of Alveoli designed to help gaseous exchange ?
- Walls are only one cell thick - short diffusion pathway
- extensive capillary network surrounds the alveoli - so they have an excellent blood supply
- huge surface area because there are millions of alveoli in each lung - which allows for a greater uptake of oxygen
Gaseous exchange
The movement of oxygen from the air into the blood , and carbon dioxide from the blood into the air
Muscles used during inspiration at rest
Diaphragm
External intercostals
Muscles used during Expiration at rest
Passive: diaphragm and external intercostals just relax
Muscles used during inspiration during exercise
Diaphragm
External intercostals
Sternocleidomastoid
Scalenes
Pectoralis minor
Muscles used during Expiration during exercise
Internal intercostals
Abdominals
What happens during inhalation (breathing in) ?
- rib cage moves upwards and outwards
- diaphragm contracts and is pulled flat
What happens during Exhalation (breathing out) ?
- Ribcage falls
- Diaphragm relaxes and rises to dome-shaped position
Inspiration
Taking air into the lungs
Expiration
Moving air out of the lungs
Tidal volume
Volume of air breathed in or out per breath
Inspiratory reserve volume (IRV)
Volume of air that can be forcibly inspired after a normal breath
Expiratory reserve volume (ERV)
Volume of air that can be forcibly expired after a normal breath
Minute ventilation
The volume of air inspired or expired per minute
How to calculate minute ventilation
Number of breaths (per min) x tidal volume
e.g. 12 x 0.5 =6 litres/min
Respiration
The taking in of oxygen and the removal of carbon dioxide
ventilation
Getting air into and out of the lungs
What effect does exercise have on these lung volumes ?
More oxygen is required so our depth of breathing increases. This means tidal volume increases because we are using more of our inspiratory reserve volume and expiratory reserve volume.
Residual volume
The amount of air that remains in the lungs after maximal expiration.
Spirometer
A device that is used to measure the volume of air inspired and expired by the lungs.
Go over graphical representation of tidal volume
Partial pressure
The pressure exerted by an individual gas when it exists within a mixture of gases.
Concentration/diffusion gradient
Often referred to as the concentration gradient. It explains how gases flow from an area of high concentration to an area of low concentration. The steeper this gradient (difference between concentration levels at high and low areas, the faster diffusion occurs.
Diffusion pathway of oxygen
Alveoli —> blood —> muscles
Diffusion pathway of carbon dioxide
Muscles —> Blood —> alveoli
What three factors are involved in the regulation of pulmonary ventilation (breathing) during exercise ?
Neural control
Chemical control
Hormonal control
What does neural control involve ?
The brain and the nervous system
What does chemical control do ?
It’s concerned with blood acidity. When blood acidity is high, the brain is informed and it sends impulses through the nervous system to increase breathing
Pulmonary ventilation
Breathing. the nervous system controls this automatically through two systems: the sympathetic and parasympathetic.
During exercise why does blood acidity increase?
as a result of an increase in the plasma concentration of carbon dioxide and an increase in lactic acid production. These changes are detected by chemoreceptors
Proprioceptors
Sensory receptors found in muscles and joints that provide information to the central nervous system about position and movement.
Baroreceptors
Baroreceptors detect a decrease in blood pressure in the aorta and carotid arteries which results in an increase in breathing rate.
Stretch-receptors
prevent over-inflation of the lungs by sending impulses to the expiratory centre
Where is the respiratory centre found ?
Medulla oblongata
Adrenaline
The hormone that increases breathing rate
How is anticipatory rise achieved?
The brain sends impulses to the adrenal glands which respond and pump adrenaline into the blood
What affect does smoking have on the respiratory system ?
-It can cause irritation of the trachea and bronchi. It reduces lung function and increases breathlessness.
-Smoking can damage the alveoli - which increases the risk of COPD
-carbon monoxide from cigarettes combines with haemoglobin in red blood cells much more readily than oxygen. This reduces the oxygen-carrying capacity of the blood, which increases breathlessness during exercise.
Cilia
microscopic hair-like projections that help to sweep away fluids and particles.
COPD
is a chronic and debilitating disease and is the name for a collection of diseases such as emphysema. The main cause of emphysema is smoking. It is a long-term, progressive disease of the lungs that causes
shortness of breath.
