Respiration System Flashcards
Define pulmonary ventilation.
Movement of air into and out of the lungs.
Give a brief description of what internal respiration means.
Internal respiration refers to the use of oxygen inside mitochondria to generate ATP (in the process of oxidative phosphorylation), and the generation of carbon dioxide as a waste product.
Give a brief description of what external respiration means.
This respiration refers to the exchange of oxygen and carbon dioxide between the atmosphere and body tissues, which is occurs via the respiratory and circulatory systems.
External respiration refers to the movement of oxygen and carbon dioxide between the atmosphere and body tissues and this can be broken down into 4 processes. What are they?
- Pulmonary ventilation.
- Gas exchange between lungs and blood.
- Movement of oxygen and carbon dioxide between the lungs and body tissues via the blood.
- Gas exchange between the blood and body tissues.
Lobes are structures that makes up the lungs. How many lobes is each lung divided into?
Right lung has 3 lobes, and left lungs has 2 lobes.
What are the upper airways referring to into the respiratory system?
The air passages in the head and neck. This includes how air can enter through the oral cavity and nasal cavity, and how both airways leads to the pharynx.
What is the pharynx?
The pharynx is a muscular tube found in the throat, that is a passageway for both food and air.
Describe the movement of air (to alveoli) in the human gas exchange system.
> Nose
Nasal cavity
Trachea
Bronchi
Bronchioles
Alveoli
How is the nasal cavity adapted to taking in air?
> The nasal cavity has a large surface area with a good blood supply, which warms the air to body temperature.
It has a hairy lining that secretes mucus to trap dust and bacteria (protecting lung tissue from irritation and infection).
How is the trachea in humans adapted to its function?
The trachea carries air from the nasal cavity to bronchi.
> The trachea is supported with C-shaped rings of cartilage, to prevents the trachea from collapsing down on itself. It is C-shaped as it allows for movement of food down the adjacent pipe, the oesophagus.
> The trachea is lined with goblet cells and ciliated epithelium. The goblet cells secretes mucus (made of glycoproteins) which traps any bacteria and pathogens in the trachea, stopping them from reaching the lungs. The cilia then sweeps this mucus back up to be coughed up.
> The tracheal walls are made of smooth muscle. The trachea is able to contract and recoil due to the elastic fibres in trachea wall. The contraction of smooth muscle reduces the size of the lumen in the trachea, possibly to reduce airflow to the lungs in the presence of harmful substances.
How are the bronchioles adapted to its function?
The bronchioles carries air from the bronchi to alveoli.
> The bronchioles also contains some smooth muscles in its walls, so when it constricts, it is able to reduce airflow to the lungs.
> The walls of the bronchioles is made up of a thin layer of flattened epithelium, making some gas exchange possible.
How are the alveoli adapted to its function?
The alveoli is the site of gas exchange is humans.
> The alveoli has high surface area. Each individual alveoli is very small in size, giving a high SA:V. But with millions of alveoli in the lungs, this increases the surface area greatly, giving a faster diffusion rate.
> Short diffusion distance - Each alveoli has one layer of squamous epithelial cells in its walls.
> Maintained concentration gradient- Each alveoli is surrounded by a network of capillaries, with a good blood supply that is constantly exchanging gases.
> Elastic tissues in the walls of the alveoli allows the alveoli to expand as air is drawn in (and then recoil).
When we breath in through our mouth (Oral cavity), it is normally during exercise (to get more in an air intake) or when our nose is blocked. However, relative to the air breathed in via the nasal cavity, the air breathed in through the oral cavity is cold and dry. Why is this?
The nasal cavity or nose is able to warm and moisturise the air we take in. It is able to warm the air because the nose has a sufficient blood supply that radiates heat. The hairy lining in the nose also secretes mucus that moisturises the air.
What is the conducting and respiratory zone and how do they differ?
The conducting zone refers to the passageway that travels from the upper parts of the respiratory system to the bronchioles.
The respiratory zone refers to the air in the lower parts of the respiratory system- this includes the terminal bronchioles and alveoli.
Apart from the locations of these zones, the zones also differ by the fact that the air in the respiratory zone takes place in gas exchange, while the air in the conducting zone does not.
Where is the larynx located and what is its function?
The larynx is found in throat and is part of the respiratory tract. The larynx contains our vocal cords, that generates sound as air passes over them.
The larynx is also responsible for ensuring food or drink does not enter the respiratory tract. The top or opening of the larynx is called the glottis and the glottis is capable of being covered by a flap of tissue called the epiglottis. During swallowing, the epiglottis is forced down, and this prevents food from entering the respiratory tract.
List the structures of the conducting zone, starting from the trachea.
Trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, terminal bronchioles and alveoli.
What is the trend in cartilage and diameter going from the trachea to alveoli?
Going from the trachea to the alveoli, there is a decrease in cartilage and diameter, which means the trachea has the most cartilage and greatest diameter. The trachea needs a lot of cartilage to support its structure.
What is the trend in smooth muscle going from the trachea to the alveoli?
Going from the trachea to the alveoli, there is an increase in smooth muscle. The presence of the smooth muscle in the tract helps gives the function of contraction to reduce diameter of the lumen to stop the passage of air, in the case of anything harmful being in the air (poisonous air).
Where are goblet cells found?
The larynx and trachea.
What is the purpose of cilia lining the trachea?
The cilia sweeps mucus up towards the glottis, which allows the mucus to be swallowed or coughed up.
What part of the respiratory tract does smoking affect, so much that smokers are coughing constantly?
Smokers cough a lot due to the damage sustained to the epithelial cell wall, more specifically, the cilia. The cilia is damaged and so does not have enough propulsion to move the mucus up the trachea. To compensate this, people who smoke cough a lot to provide propulsion to push the mucus up the trachea.
What is ‘dead space’?
Dead space refers to air that was last breathed in, and this air will also be the air we next breathe out. The volume of air in each breath that is dead space is around 150ml, and this air never reaches the alveoli for gas exchange.
When we do exercise, is it more effective to breathe more frequently or breathe in more air in each breath to gain sufficient oxygen?
Breathing in more air with each breath is more effective because it ensures a higher volume of air actually reaches the alveoli for gas exchange of oxygen, even if we still have the same volume of dead space. Breathing more frequently means that the same volume of air is restricted to reaching the alveoli in each breath, so limited (and definitely not the maximum) gas exchange occurs.
What are the functions of the conducting zone?
Provides a passageway for air to enter respiratory zone.
Adjustment of air temperature.
Humidifying the air.
What structures make up the respiratory zone?
Respiratory bronchioles, alveolar ducts, alveoli and alveolar sacs (alveolar sacs is a structure that is made from many alveoli).
Around how much alveoli is in the lungs?
Around 300 million alveoli in the lungs, but this can change with age and size.
What are alveolar pores?
What is the purpose of alveolar pores in the alveoli?
Alveolar pores are holes in the alveoli, which connects adjacent alveoli.
The alveolar pores serves as a passageway for air flow between adjacent alveoli, so each alveoli is not completely independent. Since air flows between all the alveoli, there is an equilibration of pressure throughout the lungs.
There are two types of cells in the alveoli. Where are Type 1 cells located and what is their function?
Type 1 cells are epithelial cells overlying a basement membrane. Type 1 cells are primarily responsible for efficient gas exchange between the alveoli and the blood.
In the lungs there is a fused basement membrane between the alveolar epithelium and capillary endothelium. What is this fused membrane structure, and how is it formed?
Alveoli has epithelium cells that sits on a basement membrane, and blood vessels have endothelium cells that is underlying on a basement membrane. In many places in the lungs, the basement membrane of the alveoli and capillaries are so close together that they fuse and become one basement membrane.
Gas exchange occurs over the respiratory membrane in the lungs. What is the reseparatory membrane comprised of?
Alveolar epithelium, a fused basement membrane and a capillary endothelium.
What are the functions of Type 2 cells in the alveoli and where are they located?
Type 2 cells are found along the lining of the epithelial wall in the alveoli.
The primary function of Type 2 cells is to secrete surfactant. Surfactant is a solution which contains a mixture of lipids and proteins, and this reduces the surface tension in the alveoli. The function of this is to prevent the alveoli from collapsing and holding their structure during exhalation.
Another function of these type 2 cells is that they are capable of differentiating into type 1 cells (epithelial cells), so it has a function of regenerating damaged alveolar tissue.
What is the purpose of alveolar macrophages?
Alveolar macrophages have the function on engulfing and digesting foreign material and pathogens that have made it pass through the other defense systems and barriers. These macrophages are not bound to anything and free to move around in the alveoli.
What bones are found in the thoracic cavity (chest cavity)?
Ribcage, sternum (elongated bone in the centre of the chest- breastbone) and thoracic vertebrae (bones in the chest region found in the backbone).
What muscles are found in the thoracic cavity, essential to respiration?
Internal and external intercostal muscles.
What are the functions of the thoracic cavity?
Protects the lungs and facilitates ventilation.
Where are the intercostal muscles located in the thoracic cavity?
Intercostal muscles are located in between the ribs.
What is the pleural sac?
The pleural sac is a thin fluid filled membrane that surrounds each lungs, and separates the lungs from the ribs and intercostal muscles.
What is the function of the pleural sac?
The pleural sac connects the lungs and ribcage constantly; so it makes them inseparable. The pleural sac provides flexibility as it allows the lungs to slide past the ribcage. It keeps them lubricated as well.
State the names of the inner and outer membranes of the pleural sac.
The membrane (inner?) that is connected with the lungs is called the visceral pleura. The membrane that is in contact with the ribs (outer?) is called the parietal pleura. The interior of the pleural sac is called the intrapleural space.
What is pneumothorax?
Pneumothorax is when there is a puncture or damage in the pleural sac (which can be from a wound or due to a lung health condition), which allows air to escape from the lungs and enter the thoracic cavity. This causes the lung to lose its structure and shape, due to a decrease in pressure in the lungs, as well as the pressure exerted on the lungs from the outside (in the chest cavity) from the released air.
Describe the pulmonary pressures at rest.
The lungs and the chest wall are both elastic and tend to recoil back to their normal position. A rest, the chest wall is compressed but the lungs are stretched.
At rest, there is also a negative pressure in the intrapleural space.
What are the different pulmonary pressures?
Atmospheric pressure, intra-alveolar pressure (0 at rest) and intrapleural pressure (always negative and smaller than intra-alveolar pressure).
Describe the process of inspiration in humans.
> The diaphragm contracts and moves downwards.
External intercostal muscles contract.
Ribcage is pulled upwards and outwards.
The volume of thorax (chest cavity) increases.
The pressure in the thorax drops below atmospheric pressure.
Causes air to flow in the lungs.
Describe the process of expiration in humans.
> The diaphragm relaxes.
External intercostal muscles relax.
Internal intercostal muscles can contract, if air is being pushed out forcefully (forceful expiration).
Ribcage is pulled inwards and downwards.
The volume of the thorax decreases.
The pressure in the lungs increases and rises above atmospheric pressure.
Air moves out of the lungs.
