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
Outline emphysema
Destruction of alveolar walls and permanent enlargement of air spaces which can result from smoking or alpha 1-antitrypsin deficiency. Alveolar walls normally hold bronchioles open. Damage = collapse = difficult for lungs to empty = air trapped in alveoli. Pursed lip breathing. Damage = loss of elastin = chest springs out = barrel chest
What is pneumonia?
Inflammation of the lung caused by bacteria, lung consolidates (filled with liquid) as the alveoli fill with inflammatory cells. Streptococcus pneumoniae
Name the 2 pleura and where they are found
Parietal pleura –> lines the chest wall. Visceral pleura –> cover lung
How does surface tension work?
Water molecule, +ve and –ve ends attract each other – H bonds. At surface - water molecules don’t have any charges pulling on them from above = able to get more densely packed = stronger intramolecular force = surface tension
What is the pleural fluid?
separates and lubricates 2 membranes, provides surface tension to prevent the lung from collapsing. -ve pressure keeps pleurae together = lung expands
What are the pleural fluids –ve pressures?
Inspiration = -8cmH2O (below atmosphere) Exhalation -4cmH2O (below atmosphere)
What is boyles law?
When the volume of a container increases, the pressure decreases. When the volume of a container decreases, the pressure increases
Outline LaPlaces Law
If two areas of different pressure communicate, gas will move from area of higher pressure to area of lower pressure
What can the pleural space be incorrectly filled with?
Air –> pneumothorax. Blood –> haemothorax. Pus –> empyema. Watery transudate or exudate –> pleural effusion
What is the role of surfactant?
surface tension wants to collapse the alveoli, surfactant hydrophilic heads interfere with H bond = decreases surface tension = less chance of alveoli collapse
List the order of the respiratory system
Nasal cavity, pharynx, larynx, trachea, primary right/left bronchi, secondary bronchi, bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli.
What are Clara cells?
Found in bronchioles, secrete surfactant lipoprotein stop walls sticking together, CC16 lower = lung damage, higher = leaking across air-blood barrier
What is alpha 1-antitrypsin?
It protects tissues from enzymes of inflammatory cells especially neutrophil elastase. In its absence (such as in alpha 1-antitrypsin deficiency), neutrophil elastase is free to break down elastin, which contributes to elasticity of lungs = emphysema or COPD
