ABGs Flashcards
what causes increased anion acidosis ?
MUDPILES: methanol uraemia DKA/AKA paraldehyde/phenformin iron/INH lactic acidosis ethylene glycol salicylates
where are the respiratory centres located ?
brainstem - at the upper pons (pneumotaxic centre), lower pons (apneustic centre) and medulla oblongata
when does surfactant production begin in babies ?
week 22
what week does the respiratory diverticulum form ?
week 4
by what week have the tertiary bronchial buds formed and the lungs start to grow ?
week 10
what week do the terminal bronchioles begin to form ?
week 18
what happens at week 30 ?
the mesenchyme surrounding the lungs becomes very vascular and the primary alveoli form
what is pulmonary surfactant ?
- it is released by type II pneumocytes
- helps the alveoli from collapsing
- reduces the muscular force needed to expand the lungs
- lowers the elastic recoil at low lung volumes and thus helps to prevent the alveoli from collapsing at the endow each expiration
what is the normal intracranial pressure ?
<15mmHg
what characteristic features of central chemoreceptors in the control of ventilation ?
- located in the medulla oblongata
- stimulated by arterial carbon dioxide
- relatively insensitive to hypoxia
- may be affected to changes in the pH of CSF
- during acute hypercapnia the carotid receptors will be stimulated first
symptoms in babies of surfactant deficiency
visibly distressed, tachypnoea, tachycardia, expiatory grunting, nasal flaring and chest wall recession
what can increase lung compliance ?
age, emphysema, lung surfactant, loss of lung connective tissue, upright posture
what can decrease lung compliance ?
pulmonary oedema, pulmonary fibrosis, pneumonectomy, kyphosis
what is lung compliance ?
it is defined as the change in lung volume per unit change in airway pressure
where are the peripheral chemoreceptors located ?
in the bifurcation of carotid arteries and arch of the aorta
