AS PE Pulmonary Function Flashcards
When the diaphragm contracts and the chest expands during inspiration, does the pressure within the lungs increase or decrease?
Decreases. This allow the lungs to expand and draws air in as it travels from the high pressure of outside to a low pressure inside the lungs.
Which two muscles are responsible for inspiration at rest?
Diaphragm and external intercostal muscles
Expiration is a passive process at rest, what does this mean?
No energy is required as the relaxation of the diaphragm and external intercostal muscles increases the pressure within the lungs, forcing the air out.
Which muscles are responsible for forcing the ribs and downwards and decreasing the size of the thoracic cavity during expiration when we exercise?
Rectus abdominis (Abdominal muscles) and internal intercostal muscles
Other than the external intercostal muscles and the diaphragm, which 3 muscles are recruited to aid inspiration during exercise?
Sternocleidomastoid
Scalene muscles
Pectoralis minor
Which control centre is responsible for adjusting breathing rate?
Respiratory control centre
Which nervous system is responsible for controlling breathing rate?
The autonomic nervous system. It is made up of the sympathetic and parasympathetic nervous systems which speed up and slow down the breathing rate
A nervous impulse is sent to the breathing muscles from the RCC for 2 seconds causing them to contract. Which nerve does the impulse get sent through?
Phrenic nerve
Sympathetic nerve
Name at least two types of receptors which act on the respiratory control centre
Chemoreceptors - detect CO2
Thermoreceptors - detect temperature
Proprioceptors - detect movement at joints
Baroreceptors - detect blood pressure
Is the partial pressure of oxygen higher in the alveolus or higher in the capillary surrounding the alveolus?
Higher in the alveolus. This ensures oxygen diffuses from the alveoli into the capillaries to be transported to the muscles to make energy.
Gases always move from areas of high pressure to areas of low pressure. True or false?
True. Until an equilibrium is reached
The term used to describe the movement of a gas across a semi permeable membrane is known as d……..
Diffusion
Does the rate of diffusion increase, decrease or remain the same as exercise commences?
It increases. This is due to larger concentration gradients.
What characteristics of the lungs make them efficient when exchanging gases between the alveoli and the pulmonary capillaries?
Large surface area Layer of moisture enhances oxygen uptake Membranes are semi permeable Capillaries are 1 cell thick - short diffusion pathway Haemoglobin's affinity for oxygen
Does partial pressure of oxygen in the air increase or decrease at altitude?
Decrease
Does the pressure gradient between the blood and the tissues decrease at altitude?
Yes as there are less oxygen particles in the same volume of air breathed in at altitude. This results in a decreased movement of oxygen from the blood into the tissues
What is the formula HbO2 better known as?
Oxyhaemoglobin
At the lungs, approximately how much of the haemoglobin is saturated with oxygen?
97%
Tidal volume is the volume of air inspired and expired per breath. True or false?
False. It is the volume of air inspired OR expired in one breath
What piece of equipment is used to measure lung volumes?
Spirometer
What happens to tidal volume as exercise commences?
It increases
What is minute ventilation?
Volume of air inspired or expired per minute. It is tidal volume multiplied by breaths per minute
What happens to the inspiratory reserve volume (IRV) and expiratory reserve volume (ERV) during exercise?
They both decrease, enabling tidal volume to increase
What are the sternocleidomastoid, scalene muscles and pectoralis minor used for during inspiration when we exercise?
They lift the ribs and sternum further so the thoracic cavity can expand and more air can fill the lungs. Resulting in deeper breathing.
When we exercise what happens to the process of inspiration?
The external intercostal muscles and diaphragm contract with more force, three additional muscles are recruited to help increase the volume of the thoracic cavity, this increases the rate and depth of breathing.
What happens to the process of expiration when we exercise?
It becomes an active process, the internal intercostal muscles and abdominals contract to pull the ribs down and force expiration to happen. This decreases the time it takes to breathe out
Starting with the medulla, how does the brain control breathing at rest?
Inside the medulla is the RCC, it sends an impulse down the phrenic nerve to the diaphragm and external intercostals, they contract for 2 seconds, the impulse stops and they relax for 3 seconds which causes expiration to occur.
What is the role of the chemoreceptors?
They are nerve cells which monitor the blood and detect a raise in carbon dioxide levels and a decrease in pH level. They send a nerve impulse to the medulla to increase rate and depth of breathing if CO2 levels are too high.
Where are the chemoreceptors found?
In the aortic arch and carotid artery.
When would a decrease in oxygen levels cause the rate and depth of breathing to increase?
At altitude as the air pressure is lower.
In smokers who have a decreased surface area of their lungs for diffusion.
In asthmatics as they have a reduced volume of air inspired per breath.
What process causes increased levels of CO2 and increases in body temperature?
(Aerobic and anaerobic) Respiration.
If the partial pressure of oxygen is 105mmHg in the alveolus and 40mmHg in the blood in the pulmonary capillaries, what happens?
Oxygen travels down the concentration gradient with is created. A high pO2 in the alveolus (104mmHg) and a low pO2 in the capillary (40mmHg) causes oxygen to diffuse across the semi permeable membrane into the capillary.
If the partial pressure is 46mmHg in the blood in the pulmonary capillaries and 40mmHg in the alveolus, what happens?
CO2 travels down the concentration gradient with is created. With a high pCO2 in the capillary (46mmHg) and a low pCO2 in the alveolus (40mmHg) carbon dioxide diffuses across the semi permeable membrane from the capillary into the alveolus.
Blood and muscle pH increase during exercise, true or false?
False - blood and muscle acidity increases, this decreases the pH
What is haemoglobin?
It is a protein found in red blood cells and is responsible for transporting oxygen in the blood.
What is myoglobin
It is a protein found in the muscle cells and is used to transport oxygen to the mitochondria. This supplies oxygen required for aerobic respiration.
