The Respiratory System 1.2 Flashcards
Define respiration
The taking in of oxygen and the removal of carbon dioxide
What does respiration include?
- Ventilation- getting air into and out of the lungs
- External respiration- gaseous exchange between the lungs and the blood
- Transport of gases
- Internal respiration- exchange of gases between the blood in the capillaries and the body cells
- Cellular respiration
What is the order of the passage of air?
Nose/mouth
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
(nearly lobbed the ball brilliantly again)
Define diffusion
The movement of gas molecules from an area of high concentration to an area of low concentration
Define gaseous exchange
Movement of oxygen from the air into the blood and carbon dioxide from the blood into the air
What are the 3 properties of the alveoli that help during gaseous exchange?
B-Big surface area
O-One cell thick
G- Good blood supply
When inspiring what muscles are used at rest and when exercising?
Inspiration
Muscles used during breathing at rest:
* Diaphragm
* External intercostals
Muscles used during exercise:
Diaphragm
External intercostals
Sternocleidomastoid
Scalenes
Pectoralis major
When expiring what muscles are used at rest and when exercising?
Expiration
Muscles used during breathing at rest:
* Diaphragm
* External intercostals
Muscles used during exercise:
* Internal intercostals
* Abdominals
What is tidal volume?
Volume of air breathed in or out per breath
What is your inspiratory reserve volume?
Volume of air that can be forcibly inspired after a normal breath
What is your expiratory reserve volume?
Volume of air that can be forcibly expired after a normal breath
What is your residual volume?
The amount of air that remains in the lungs after maximal expiration
Explain gaseous exchange at the alveoli
The partial pressure of oxygen (po2) in the alveoli (100mmHg) is higher than the partial pressure of oxygen in the capillary blood vessles (40mmHg)
This is because oxygen has been removed by the working muscles so its concentration in the blood is lower & therefore so is its partial pressure
The bigger the concentration/diffusion gradient the faster diffusion will be
Oxygen will diffuse from the alveoli into the blood until the pressure is equal in both
What are the two diffusion pathways of oxygen and carbon dioxide?
Diffusion pathway of oxygen:
Alveoli- Blood- Muscles
Diffusion pathway of carbon dioxide:
Muscles- Blood- Alveoli
(opposites)
Explain gaseous exchange at the muscles.
In the capillary membranes surrounding the muscle the partial pressure of oxygen is 40mmHg and it is 100mmHg in the blood
Diffusion occurs until equilibrium is reached
Conversley the partial pressure of carbon dioxide in the blood (40mmHg) is lower than in the tissues (46mmHg) so again diffusion occurs & CO2 moves into the blood to be transported to the lungs
What are the 3 factors involved in the regulation of pulmonary ventilation?
Neural control
Chemical control
Hormonal control
What is neural control and chemical control?
Neural control involves the brain and the nervous system
Chemical control is concerned with blood acidity
- Both of these work together to regulate breathing
- When blood acidity is high the brain is informed and it sends impulses through the nervous system to increase breathing
What is pulmanory ventilation?
- Pulmonary ventilation is breathing
The nervous system controls this automatically through two systems: The sympathetic and parasympathetic
What do the sympathetic and parasympathetic nervous system do?
Sympathetic- Prepares body for exercise so it will increase breathing rate
Parasympathetic- Lower breathing rate, heart rate
The respiratory system in the medulla oblongata of the brain controls the rate and depth of breathing and uses both neural and chemical control
What does the inspiratory centre do?
Sends out nerve impluses via the phrenic nerve to the inspiratory muscles (diaphragm& intercostals) to cause them to contract
impulse lasts for approx 2 seconds and then the impulses stop and passive expiration occurs due to the elastic recoil of the lungs
What other factors affect neural control of breathing?
Mechanical factors- Proprioceptors provide feedback to the respiratory centre to increase breathing during exercise
Baroreceptors- a decrease in blood pressure detected by baroreceptors in the aorta & cartoid arteries results in an increase in breathing rate
Stretch receptors- During exercise lungs stretched more
Stretch receptors prevent over inflation of the lungs by sending impulses to the expiratory centre & then down the intercostal nerve to the expiratory muscles so that expiration occurs
What is the order of neural/chemical control for inspiration?
Receptors- Medulla- Phrenic Nerve- Diaphragm & External Intercostals
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What is the order of neural/chemical control for expiration?
Receptors- Medulla- Intercostal nerve- Abdominals & internal intercostals
What is adrenaline?
The hormone that increases breathing rate in preparation for exercise
