C6 - Respiratory System Flashcards
What filters air in the nasal cavity?
Mucous membranes and nasal hairs (vibrissae)
Where does the pharynx reside? And where how is it different from the larynx in terms of what contains food and air?
The pharynx is behind the nasal cavity and at the back of the mouth. It is a pathway for both food and air while the larynx which lies below the pharynx is only a pathway for air.
How is food kept out of the respiratory tract?
This is due to the larynx being covered by the epiglottis during swallowing
What does the larynx contain that is maneuvered using skeletal muscle and cartilage?
Vocal cords
After the larynx where does the air go?
The trachea
How does air get from the trachea to where gas exchange occurs?
After the trachea it goes into one of two mainstream bronchi, they then continue to divide into smaller structures known as bronchioles, which further divide until they end in tiny balloon like structures called alveoli (this is where gas exchange occurs)
The bronchi and trachea are coated with what to catch material that has made it last the mucous membranes?
Ciliated epithelial cells
What is each alveolus coated in? What is its purpose?
Surfactant, it is a detergent that lowers surface tension and prevents the alveolus from collapsing on itself
What is the main difference between the right and left lung? And why is there this difference?
The left lung only has 2 lobes, while the right has 3. This is due to the position of the heart in the thoracic cavity
What forms the outside of the thoracic cavity? (VERY outside)
Chest wall
What membranes surround each lung? Which membrane is adjacent to the lung while which ones is the outer part? What space is in between these two membranes?
Pleurae. The surface adjacent to the lung is the visceral pleura while the outer part is the parietal pleura. In between is the intrapleural space
What muscle divides the thoracic cavity from the abdominal cavity?
The diaphragm
The what lubricates the two pleural surfaces?
The thin layer of fluid in the intrapleural space
Inhalation is an active process, we use what muscles to expand the thoracic cavity?
Our diaphragm and external intercostal muscles
Exhalation does not have to be an active process, but if we wanted to speed up the process, what muscles would we use?
The internal intercostal muscles and abdominal muscles (which expose the external intercostals)
What part of breathing requires muscle contraction?
Inspiration, in order to create the negative pressure in the thoracic cavity driving air into the lunges muscles are need
What is emphysema charcaterized by? Thus What part of the breathing process is hardest with a patient that presents with emphysema?
It’s characterized by the destruction of the alveolar walls, results in reduced elastic recoil of the lungs, making the process of exhalation extremely difficult
-mostly caused by cigarette smoking
What is TLC?
Total lung capacity: it’s the maximum volume of air in the lunges when one inhales completely (usually around 6-7 liters)
What is RV in terms of lung volume?
Residual volume: the volume of air remaining in the lungs when one exhales completely
What is VC in terms of lung volume?
Vital capacity: the difference between the minimum and maximum volume of air in the lungs (TLC-RV)
What is TV in terms of lung volume?
Tidal volume: the volume of air inhaled or exhaled in a normal breath
What is ERV vs IRV in terms of lung volume?
ERV is expiratory reserve volume: the volume of additional air that can be forcibly exhaled after a normal exhalation
IRV is inspiration reserve volume: the volume of additional air that can be forcibly inhaled after a normal inhalation
Breathing required input from our nervous control center, ventilation is primarily regulated by a collection of neurons where? How does it control the ventilation rate?
The medulla oblongata, called the ventilation center that fires rhythmically to cause regular contractions of respiratory muscles
The neurons contain chemoreceptors that are primarily sensitive to CO2 concentration, as the partial pressure of CO2 in the blood rises respiration rate will increase so that more CO2 is expelled
What is the main function of the lungs
Gas exchange
How does gas exchange occur in the process of blood from the heart and back to it?
Each alveolus is surrounded by a metwork of blood capillaries, these capalaries bring deoxygenated blood from the pulmonary arteries which originates from the right ventricle of the heart. Facilitation of CO2 goes from the blood into the alveoli, and oxygen into the blood from the alveoli. Oxygenated blood then returns to the left atrium of the heart via the pulmonary veins
What is the driving force for gas exchange?
The pressure differential of the gasses
Because the gradient between the blood and air in the lungs is already present as the blood enters the lungs, what does this mean in terms of energy needed for gas exchange?
There is no energy that is needed
What is the natural response of hemoglobin to decreased carbon dioxide concentration in the environment?
To decrease the unloading of oxygen into tissues
In the short and long term what is the main way that our respiratory systems would adjust if we moved to higher altitudes where less oxygen is available?
Short term: body makes more red blood cells to ensure adequate delivery of oxygen
Long term: body could develop more blood vessels to facilitate more distribution of oxygen to tissues
Describe the thermal energy retainment and dissipation in the process of vasodilation and vasoconstriction
Vasodilation: as capillaries expand, more blood can pass through the vessels and a larger amount of thermal energy can be dissipated
Vasoconstriction: as capillaries contract, less blood can pass through them, conserving thermal energy
The first line of defense for immune function in the respiratory system is what?
The small hairs (vibrissae) in the nasal cavity that help to trap particulate matter and potentially infectious particles
The nasal cavity also contains an enzyme called lysozyme, where else is it found, and what immune function does it have?
Also found in tears and saliva, lysozyme is able to attach the peptidoglycan walls of gram-positive bacteria
Describe the mechanism referred to as the mucociliary escalator
Internal airways are linked with mucus, which traps particular matter, underlying cilia then propel the mucus up the respiratory tract to the oral cavity, where it can be expelled or swallowed
What are the main 2 immune cells that populate the lungs and alveoli? Describe their functions
Macrophages, they engulf and digest pathogens and signal to the rest of the immune system that there is an invader
Mast cells, these cells have preformed antibodies in their surfaces, when the right substance attaches to the antibody, the mast cell releases inflammatory chemicals into the surrounding area to promote an immune response
Unfortunately, mast cells antibodies are often reactive to substances such as pollen and molds, what does this mean?
That they provide the inflammatory chemicals that mediate allergic reactions
What type of antibodies are on the mucosal surfaces?
IgA
Atypical pneumonia is often caused by a very small bacteria called mycoplasma pneumoniae. What is the underlying concept behind how it causes a prolonged cough?
This is because it damages epithelial cells lining the lung and paralyzes the cilia lining the respiratory tract. The lack of cilia makes it much more difficult to clear mucous from the lungs, the cough lasts until the respiratory epithelial cells have recovered and the cilia are once again functional
What is the bicarbonate buffer system equation?
CO2 (g) + H2O (l) >/< H2CO3 (aq) >/< H+ (aq) + HCO3- (aq)
The human body aims to maintain a pH in what range in the blood?
7.35-7.45
What happens when pH is lower?
When pH is lower, hydrogen concentration is higher. The acid sensing chemoreceptors just outside of the BBB send signals to the brain to increase respirations. (Increase hydrogen ion concentration will cause a shift in the bicarbonate buffer system, generating more CO2)
Increase in respiration causes more CO2 to be blown off, shifting the buffer equation to the left
If the blood is too basic it will seek to increase acidity, how will it do this?
Decrease in respiration, more carbon dioxide will be retained, shifting the buffer equation to the right and produce more bicarbonate ions and hydrogen ions decreasing pH
If H+ is an acid and HCO3- is a base, then why doesn’t increasing both of them yield a constant pH?
This is because H+ is a strong acid while HCO3- is a weak base
