1.2: The Respiratory System Flashcards
1
Q
What is respiration?
A
- ventilation - getting air into/out the lungs.
- external respiration - gaseous exchange between the lungs and blood
- transport of gases
- internal respiration - exchange of gases between the blood in capillaries and the body cells
- cellular respiration: the metabolic reactions and process that take place on a cell to obtain energy from fuels such as glucose.
2
Q
Pathway of air?
A
- in through nose and mouth
- pharynx
- larynx
- trachea
- bronchi
- bronchioles
- alveoli
3
Q
What are the alveoli?
A
- responsible for the exchange of gases between the lungs and the blood. This occurs via diffusion.
4
Q
Diffusion definition:
A
- the movement of gas molecules from an area of high concentration or partial pressure to an area of low concentration or partial pressure.
5
Q
What is the structure of alveoli?
A
- designed to help gaseous exchange
- walls are very thin (one cell think) meaning there is a short diffusion pathway. There are only two layers of cells from the air in the alveoli to the blood.
- an extensive capillary network surrounds the alveoli: good blood supply
- large surface area: due to the amount of alveoli in each lung, which allows for a greater uptake or oxygen.
6
Q
What is gaseous exchange?
A
- the movement of oxygen form the air into the blood, and carbon dioxide from the blood into the air.
7
Q
What is the method of inspiration?
A
- the intercostal muscles contract and pull the rib cage up and out.
- the diaphragm contracts causing it to flatten.
- the thoracic (chest) cavity gets larger causing pressure in the lungs to decrease.
- air moves into the lungs from the higher outside pressure
8
Q
What muscles are used during breathing at rest - inspiration?
A
- diaphragm
- external intercostals
9
Q
What muscles are used during exercise - inspiration?
A
- diaphragm
- external intercostals
- sternocleidomastoid
- scalenes
- pectoralis minor
10
Q
what is the method of expiration?
A
- the intercostal muscles relax and so the rib cage falls down and in.
- the diaphragm relaxes pushing it up into a dome-shape.
- the thoracic (chest) cavity gets smaller and so pressure in the lungs increases.
- air flows out of the lungs.
11
Q
What are the muscles used during breathing at rest - expiration?
A
- passive: diaphragm and external intercostals just relax.
12
Q
What muscles are used during exercise - expiration?
A
- internal intercostals
- abdominals
13
Q
What is tidal volume?
A
- the volume of air breathed in or out per breath
- increases during exercise
14
Q
What is minute ventilation?
A
- the volume of air inspired or expired per minute.
- number of breaths (per min) x tidal volume = minute ventilation
- big increase during exercise
- the more demanding the physical activity is, the more breathing increases to meet the extra oxygen demand.
15
Q
What is the inspiratory reserve volume (IRV)?
A
- the volume of air that can be forcibly inspired after a normal breath.
- decreases during exercise
16
Q
What is the expiratory reserve volume (ERV)?
A
- the volume of air that can be forcibly exhaled after a normal breath.
- slight decrease during exercise
17
Q
What is residual volume?
A
- the amount of air that remains in the lungs after maximal expiration
- remains the same during exercise - does NOT change
18
Q
What is a spirometer?
A
- a device that is used to measure the volume of air inspired and expired by the lungs.
19
Q
How does a spirometer work?
A
- an individual breathes in and out of a sealed chamber through a mouthpiece.
- this makes the chamber inflate and deflate and as this happens, a pen recorder traces the breathing movements onto a chart.
20
Q
What is the purpose of gaseous exchange?
A
- getting oxygen in air into the lungs so that it can diffuse into the blood and be transported to the cells of the body.
- the removal of carbon dioxide.
21
Q
What is partial pressure?
A
- the pressure exerted by an individual has when it exists within a mixture of gases.
22
Q
What happens during gaseous exchange at the alveoli?
A
- the particle pressure of oxygen in the alveoli is higher than the pp of oxygen in the capillary blood vessels. This is because O2 has been removed by the working muscles so its concentration in the blood is lower, therefore so is the pp.
- the difference in pp is called concentration gradient and the bigger the gradient the faster diffusion will be.
- oxygen will diffuse from the alveoli into the blood until the pressure is equal.
- CO2: the pp of CO2 in the blood entering the alveolar capillaries is high than in the alveoli so CO2 diffuses into the alveoli from the blood until the pressure is equal.
23
Q
What happens during gaseous exchange at the muscles?
A
- partial pressure of oxygen has to be lower at the tissues than in the blood for diffusion to occur.
- in the capillary membranes surrounding the muscle the partial pressure of oxygen is lower than in the blood. This allows oxygen to diffuse from the blood into the muscle until equilibrium is reached.
- the partial pressure of CO2 in the blood is lower than in the tissues so diffusion occurs and CO2 moves into the blood o be transported to the lungs.
24
Q
What are the three factors involved in the regulation of pulmonary ventilation?
A
- neural control
- chemical control
- hormonal control
25
What is neural and chemical control?
- neural control: involves the brain and the nervous system
| - chemical control: concerned with blood acidity.
26
What do neural and chemical control do?
- work together as a team to regulate breathing
- when blood acidity is high, the brain is informed and it sends impulses through the nervous system to increase breathing
27
How does the sympathetic nervous system control pulmonary ventilation?
- prepares body for exercise so will increase breathing rate
28
How does the parasympathetic nervous system control pulmonary ventilation?
- lowers breathing rate
29
What is the respiratory centre?
- located in the medulla oblongata of the brain and controls the rate and depth of breathing. Uses both neural and chemical control.
- stimulated by an increased concentration of CO2 to increase the respiratory rate.
- two main areas: inspiratory centre: responsible for inspiration/expiration
Expiratory centre stimulates the expiratory muscles during exercise.
30
What is the inspiratory centre?
- sends out nerve impulses via the phrenic nerve to the inspiratory muscles to cause them to context. This stimulation acts for approx 2 secs and then the impulses stop and passive expiration occurs due to the elastic recoil of the lungs.
31
What does the respiratory centre do?
- responds to changes in blood chemistry.
- changes are detected by chemoreceptors and they send impulses to the inspiratory centre to increase ventilation until the blood acidity has returned to normal. The respiratory centre send impulses down the phrenic nerve to stimulate more inspiratory muscles
32
What are other factors affecting neutral 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 and carotid arteries results in an increase in breathing rate.
- stretch receptors: prevent over-inflation of the lungs by sending impulses to the expiratory centre and then down the intercostal nerve to the expiratory muscles so expiration occurs.
33
Control of ventilation diagram:
- see textbook (pg26)
34
What lifestyle choices impact on health?
- what people eat
- how much people exercise
- how much alcohol people drink
- whether people smoke
35
What is the effect of smoking on the respiratory system.
- can cause irritation of the trachea and bronchi
- reduces lung function and increases breathlessness caused by the narrowing of the lungs’ airways.
- smoke damages the cells lining the trachea, bronchi and bronchioles. Cilia is on the cell’s surface, when they are damaged excess mucus is built up leading to smoker’s cough to try and rid of the mucus.
- damage the alveoli as those walls break down and join together forming larger air spaces - reduced efficient of gaseous exchange increasing the risk of COPD
- also affects oxygen transport as carbon monoxide from cigarettes combines with haemoglobin in RBCs more readily than oxygen. This reduces the oxygen-carrying capacity of the blood, increases breathlessness during exercise.
36
What are cilia?
- microscopic hair-like projections that help to sweep away fluids and particles.
37
What is COPD?
- chronic obstructive pulmonary disease
- a chronic and debilitating disease and is the name for a collection of diseases such as emphysema.
- the main cause of emphysema is smoking
- is a long-term, progressive disease of the lungs that causes shorting of breath.
38
What is the diffusion pathway of oxygen?
- alveoli, blood, muscles
39
What is the diffusion pathway of carbon dioxide?
- muscles, blood, alveoli
40
What is the Bohr Shift?
the shift to the right of the oxyhaemoglobin curve in response to an increase in PCO2 or a decrease in pH, or both (more acidic blood), increase in blood temperature.
- Cause oxyhaemoglobin to dissociating the oxygen
