The Respiratory System Flashcards
How much pulmonary vasculature makes up the lungs weight?
Pulmonary vasculature = 500ml blood = 40% lung weight
Describe what happens during inhalation?
Diaphragm contracts = moves down, increasing volume of thoracic cavity = pressure inside decreases, air moves from an area of higher pressure, the atmosphere, to an area of lower pressure, the lungs
What happens during exhalation?
diaphragm relaxes, moves up = reduces volume of thoracic cavity = intrapulmonary pressure increases = Air flows out of Lungs to lower atmospheric pressure
Where is odour detected?
Olfactory region –> thick pseudostratified columnar epithelium, dendrite + non-motile cilia detect odour – no goblet cells
What are the secretion in the trachea and bronchi?
mucins, water, serum proteins, lysozyme (destroys bacteria), antiproteases (inactivate bacterial enzymes)
Describe the nasal non-olfactory region
Non-olfactory region –> pseudostratified ciliated epithelium, mucous glands, venous plexus swells alternating nostril airflow
Outline the structures in the larynx
Larynx = true vocal cord – open close many times, ventricles contribute to resonance of voice. Vocal cord (help stop foreign objects) = vocal ligament + vocalis muscle
Describe the trachea
ridged, C shaped rings to keep it open – transform to bone with ageing. Submucosa thicker in COPD = small lumen
What is structurally different between the trachea and bronchi?
trachea = C shaped rings, bronchi = rings completely encircle lumen
When is the respiratory system intrapulmonary?
secondary bronchi
Describe the bronchioles
Bronchioles = blood supply pulmonary arteries (deoxygenated) pulmonary vein (oxygenated) – NO CARTILAGE (allows constriction = bronchoconstriction), contracts in asthma. Clara cells = secrete surfactant lipoprotein stop walls sticking together.
Name the smallest airway and its key feature
Terminal bronchioles = smallest airway, no goblet cells – stop drowning in mucus
Where are the mucous membranes present
Conducting zone = MUCOUS MEMBRANE
The pleural sacs are what type of membrane
Serous membrane
What is the respiratory zone?
Respiratory zone = gas exchange – abundant capillaries – respiratory bronc. bronchioles, alveolar ducts, alveolar sacs, alveoli
Describe the alveoli and the cells types present
90% cover by type I pneumocytes (squamous), 10% type II pneumocytes (cuboidal) secrete surfactant, devel until 8yrs, 300 million, surrounded by basketwork of elastin/capillaries/reticular fibres, air as close as 0.2μm from blood
How does hyperventilating lead to fainting?
Drop in CO2 due to hyperventilating = hypocapnia – low CO2 = less carbonic acid = blood pH rises (low pH = changes shape Hb, high pH = vasoconstriction) not enough blood to the brain = faint
Why does oxygen dissociate from haemoglobin?
Active tissue burns through oxygen – low partial pressure = oxyhaemoglobin loses oxygen from plasma to tissue. Other triggers = heat (changes Hb shape), CO2 (binds Hb, changing shape + makes blood more acidic H+ bind) – activate the release of oxygen = lower Hb affinity for oxygen
What is the Haldane effect?
Deoxygenated blood can carry increasing amounts of CO2, whereas oxygenated blood has a reduced CO2 capacity.
What is the Bohr Effect?
haemoglobin’s oxygen binding affinity is inversely related both to acidity and conc of CO2
How can someone get a hoarse voice?
Hoarse voice = impinging on left recurrent laryngeal nerve – loops under aorta (can be caused by aortic aneurism)
In regards to respiratory anatomy how can wasting in the lower arm be caused?
Muscle wasting lower arm = cancer in lung apex impinges brachial plexus
What causes paralysis on one side of the diaphragm?
tumour impinges left/right phrenic nerve = ipsilateral elevation
Describe COPD
Caused by smoking or alpha 1-antitrypsin def: Goblet cell hyperplasia, smaller proportion of ciliated cells, hypertrophy of submucous glands = more mucus and fewer cilia to move mucus