State the three primary functions of the nose.
Heat or condition inspired air, Humidify, Filter
Describe the functions of the turbinates.
- There are three bony protrusions on the lateral walls of the nasal cavity called the superior, middle and inferior nasal turbinates.
- The turbinates:
- Separate inspired gas into many different airstreams, in other words, they cause turbulence in the air to increase the contact area between the inspired air and the warm, moist surfacer of the nasal mucosa
- Play a major role in the humidification and warming of inspired air
Describe the impact of intubation on inspired air.
It bypasses the nose and its functions
- Endotracheal tubes, nasal endotracheal tubes and tracheostomy tubes bypass the patients upper airway to better ventilate and oxygenate the patient. However, failure to properly humidify and warmed can cause dehydration of the patients mucus layer of the tracheobronchial tree. This dehydration causes the mucous layer to become very thick and immobile, and the mucus itself becomes thick and sticky.
Name the structure that is the narrowest part of the upper airway (adults/babies).
Adult: The Glottis
Babies: cricoid cartilage..
Label the structures of the upper airway.
- The nose
- Oral cavity
- The pharynx
- The larynx
Describe the changes in the epithelium of the lower airway as it progresses down toward the bronchioles.
Epithelial cells move from columnar to cuboidal and the squamous
- The epithelial lining is predominantly composed of pseudostratified ciliated columnar epithelium interspersed with mucous glands.
- The pseudostratified ciliated columnar epithelium extends from the trachea to the respiratory bronchioles.
- As the bronchioles become progressively smaller, the columnar structure of the epithelium decreases in height and appears more cuboidal. The cilia also begin to progressively disappear in the terminal bronchioles and are completely absent in the respiratory bronchioles
Name the alveolar cell types and functions.
Alveolar Type I cells: Primarily responsible for the exchange of oxygen and carbon dioxide between the blood and the lung.
Alveolar Type II cells: Primarily responsible for the stabilization of the alveoli. Surfactant is also produced by these cells.
- Type 1 (squamous pneumocyte)
- Thin cells that form about 95% of the alveolar surface
- Range from 0.2 to 0.5 um thick and are the major site for alveolar gas exchange
- Type II (granular pneumocyte)
- Make up the remaining 5% of total alveolar surface
- Primary source of pulmonary surfactant
- Main source of support for the alveoli
- Type III (alveolar macrophages)
- Play a major role in removing bacteria and other foreign particles that are deposited within the cell
Name the structure that covers the opening of the larynx to keep food from going into the lungs during swallowing.
Explain why an endotracheal tube is more likely to be inserted into the right mainstem as opposed to the left mainstem bronchus.
Because of the angle, the right main stem has more of a vertical orientation. Right main is about a 25 degree angle. Left main is about 40-60 degrees.
- The endotracheal tube is more likely to be inserted into the right mainstem bronchi because:
- The right main stem is wider than the left
- The right mainstem is more vertical than the left
- The right mainstem is about 5 cm shorter than the left
*Differentiate between bronchi and bronchioles.
- Cartilaginous (aka; conducting zone)
Discuss what differentiates conducting airways from the areas of gas exchange.
- Conducting airways carry the inspired air from the external environment into the lungs, this area of the airway does not conduct any type of gas exchange
- Areas of gas exchange is where the inspired air is perfused through the alveoli/capillaries and carried to the rest of the body
- Essentially the conducting airway does not contain alveoli whereas the areas for gas exchange do.
Describe how cilia function and their role in mucociliary clearance.
- Under normal circumstances, cilia move in a wavelike fashion through the less viscous sol layer and continually strike the innermost portion of the gel layer.
- This action propels the mucous layer, along with any foreign particles stuck to the gel layer, towards the larynx at an estimated average rate of 2cm per minute.
- Once the mucous reaches the larynx, the cough mechanism moves secretions beyond the larynx and into the oropharynx.
*Describe the interface at which gas exchange occurs.
- Aveolar-Capillary Membrane:
- Type 1 Alveolar cells
- Makes up 95% surface area
- Cannot reproduce
- Main site for gas exchange
- Type II alveolar cells
- Make up remaining 5% of surface area
- Replace dying/damaged type I cells
- Main source for surfactant
- Stabilize the alveoli
- Type III alveolar cells
- Alveolar macrophages
Name the primary neurotransmitters in the sympathetic and parasympathetic nervous systems.
Sympathetic: Epineprine / Norepinephrine
Describe the typical effects of sympathetic and parasympathetic nervous system stimulation.
Increases heart production
Which leads to increase cAMP which leads to smooth muscle relaxation and mast cell stabilazation
Decreases heart production
- SNS: Stimulation of the sympathetic nervous system will:
- Increase HR
- Increase BP
- Decreased Secretions
- PNS: Stimulation of the sympathetic nervous system will:
- Decrease HR
- Decrease BP
- Increased Secretions
*Describe the effects of Beta 1 receptor stimulation.
When Beta1 is stimulated, the patient will see cardiac constriction and increased cardiac rate
Describe the effects of Beta 2 receptor stimulation.
- When beta2 is stimulated, the patient will experience bronchodilation/relaxation of the bronchial smooth muscle
Define cAMP and describe its effect on bronchial smooth muscle.
Increased levels of cAMP will cause relaxation of bronchial smooth muscle
*Describe the effect a drug that inhibits phosphodiesterase (the enzyme that breaks down cAMP) would have on bronchial smooth muscle.
If there is a drug introduced to a patient that inhibits the break down of cAMP, there will be a constant presence of cAMP in the body/ over abundance of cAMP, therefor the patient will experience constant bronchial smooth muscle relaxation
*Describe how atropine exerts its parasympatholytic (anticholinergic) effect, as well as the effect it has on heart rate.
- Atropine, an agent that blocks a parasympathetic effect, being introduced to a patient will stimulate the sympathetic nervous system to take over. Therefor, the patient will experience relaxation of the bronchial smooth muscle but will also experience an increase in HR and BP
Be able to label structures of the thoracic cage.
Clavicle, Manubriosternal joint (sternal angle or angle of Louis), Xiphoid process, Manubrium
- Clavicle (collar bone)
- Manubrium (triangular bone on top of sternum)
- Manubriosternal joint (joint that connect manubrium to sternum)
- Body of the sternum (long bone down the middle of the chest)
- Xiphoid process (pointy bone at the bottom of the sternum)
- Sternal notch (notch at the top of the manubrium)
- Scapula (shoulder blade)
Name the accessory muscles of inspiration.
External intercostals, pectoralis major, trapezius / scalenus muscles, sternocleidomastoid (5)
Name the primary accessory muscles of expiration.
Rectus abdominis, external abdominis obliquus, internal abdominis obliquus, transversus abdominis, internal intercostal (5)
Name substances that are released when mast cells degranulate.
Histamine, heparin, eosinophilic chemotaxic factor of anaphylaxis, leukotrienes, platelet activating factor