ILA 4 - Respiratory Failure Flashcards
What anatomical structures does air pass through to get to the alveoli? Describe the endothelium at each stage
1a. Nose - first third is statified squamous, then posterior 2/3rds is PSCCE + goblet (Psuedostratified cilliated columnar epithelium)
1b. Mouth -
2. Pharynx (naso, oro, larynx) - PSCCE + goblet
3. Larynx - PSCCE + goblet (vocal cords are strat squamous, contain skeletal muscle and glands)
4. Trachea - PSCCE, cartilage, MALT nodule, LYMPH node
5. R and L main bronchi, PSCCE, cartilage
6. Bronchi - PSCCE
7. Respiratory bronchioles - simple CUBODIAL EPI, larger than terminal
8. Terminal bronchioles - SIMPLE CUBODIAL (secretes). sparsely ciliated - CLARA cells, smooth muscle ring
- Alveoli - simple squamous
Type 1 - higher SA, flatter, 40% pop
Type 2 - secrete SURFACTANT, rounder, 60% pop
alveolar macrophages - contain black ingested carbon
How does the body detect O2/Co2?
- Chemoreceptors
a) Peripheral = carotid and aortic bodies
Aortic body - detects changes in O2 and CO2 not PH
Carotid body - detects blood O2, CO2 and PH
Peripheral receptors has a lower effect on breathing than central receptors
b) Central = medullary (detect changes in pH of cerebrospinal fluid, due to Co2 dissociation - however Co2 cannot travel through the BBB)
detected by these, then stimulates breathing centre in the brain to return to normal levels
- Stretch receptors in the lung
when the lung over stretches the Hering-breuer reflex reduces overstretching
(HCO3 2- is unaffected, the changes occur over time)
What is the strongest drive the breathe?
Central chemoreceptors have a greater affect on breathing
Describe the thoracic pressure changes during inspiration
- Contraction of diaphragm and intercostal muscles
- Ribs 2-6 = move in a pump handle movement
- Lower ribs = move in bucket handle movement
- Increases volume of the thorax, this draws the wall of the thorax away from the lung surface = decreases the INTRAPLEURAL PRESSURE (because volume has increased)
- This decrease in intrapleural pressure causes an increase in TRANSPULMONARY PRESSURE that is higher than the elastic recoil of the lungs - this allows the lungs to expand further
- This increases the diameter of the alveoli leading to a fall in ALVEOLAR PRESSURE
- The pressure in the Alveolar is now SUBATMOSPHERIC causing bulk movement of air to flow from the atmosphere into the lungs
yay :) - At the end of respiration the pressure in the air equals the pressure of the atmosphere, and the more inflated lungs have a greater elastic recoil which balances out the decreased intrapleural pressure
What is respiratory failure? Type 1/Type 2
Respiratory failure = a syndrome in which the resp system fails to oxygenate or eliminate Co2
Type 1 - decrease in O2
Type 2 - decrease in O2 and increase in CO2
What is the difference between LYMPH node and MALT node?
LYMPH = discrete, encapsulated collection of lymphoidal tissue
MALT (mucosa - associated lymph tissue) = no capsule, intimately related to epithelium , highly populated by T and B lymph, plasma cells and macrophages
Which pneumocyte secretes surfactant? Why? What are the main differences between the two types of cell?
Type 1 - higher SA, flatter, 40% pop
Type 2 - secrete SURFACTANT, rounder, 60% pop
SURFACTANT reduces surface tension
Describe the anatomy of the nasal cavity, what regions
- Vestibule - area surrounding external opening
- Olfactory region - roof of nasal cavity, lined by olfactory cells with olfactory receptors (contains Bowman’s glands)
- Respiratory region - largest,PSCCE, ciliated + goblet cells
Conchae - 3 curved shelves of bone projected out of the lateral walls, inferior, middle and superior
- create four pathways called meatuses
a) increase SA
b) slow down air so that it is slow and turbulent, this means there is more time for the air to be humidifed
High vascular supply - internal and external carotid arteries
Contains cilia and mucus to filter out unwanted contaminants
Describe the anatomy of the pharynx
- Muscular tube that connects to the larynx and the oesophagus
- base of skull to C6
- Nasopharynx, continuation of nasal cavity, conditions inspired air and propagates it to the larynx RESP + goblet, contains ADENOID TONSILS
- Oropharynx, located between soft palate and superior border of epiglottis, posterior 1/3 of tongue, LINGUINAL tonsils and PALATINE tonsils
- Laryngopharynx, contains middle and inferior constrictors (longitudinal and circular muscles),
What is the epiglottis
Flap of elastic cartilage, it switches access between the esophagus and trachea
Name the three tonsils and their location
ADENOID - nasopharynx (immunity)
LINGUINAL- inferior to tongue
PALATINE, arches of oral cavity - oropharynx
What are the circular and longitudinal muscles of the pharynx innervated by?
Both types of innervated by VAGUS nerve, expect sternopharyngeus - innervated by glossopharyngeal
Which muscle of the pharynx is not innervated the vagus nerve?
sternopharyngeus - innervated by glossopharyngeal
How do the circular muscles function? Where are they found
Circular muscles contract sequentially from superior to inferior to constrict the lumen and propel bolus of food inferiorly to the oesophagus
Superior pharyngeal constrictor - oropharynx
Middle pharyngeal constrictor - laryngopharynx
Inferior pharyngeal constrictor - laryngopharynx, two components superior(oblique fibres) and inferior (horizontal fibres that attach to the cricoid cartilage)
How do the longitudinal muscles function? Where are they found
They shorten and widen the pharynx, and elevate the larynx during swallowing
- Stylopharyngeus - from styloid process of temporal bone to pharynx (CNXI)
- Palatopharyngeus - from hard palate of oral cavity to pharynx (CNX)
- Salpingopharyngeus - from eustachian tube to pharynx (2nd function = also opens the eustachian tube to equalise pressure in middle ear with atmosphere)
