ABGs

Question 1

what causes increased anion acidosis ?

Answer 1

MUDPILES:
methanol
uraemia 
DKA/AKA
paraldehyde/phenformin
iron/INH
lactic acidosis 
ethylene glycol
salicylates

Question 2

where are the respiratory centres located ?

Answer 2

brainstem - at the upper pons (pneumotaxic centre), lower pons (apneustic centre) and medulla oblongata

Question 3

when does surfactant production begin in babies ?

Answer 3

week 22

Question 4

what week does the respiratory diverticulum form ?

Answer 4

week 4

Question 5

by what week have the tertiary bronchial buds formed and the lungs start to grow ?

Answer 5

week 10

Question 6

what week do the terminal bronchioles begin to form ?

Answer 6

week 18

Question 7

what happens at week 30 ?

Answer 7

the mesenchyme surrounding the lungs becomes very vascular and the primary alveoli form

Question 8

what is pulmonary surfactant ?

Answer 8

• 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

Question 9

what is the normal intracranial pressure ?

Answer 9

<15mmHg

Question 10

what characteristic features of central chemoreceptors in the control of ventilation ?

Answer 10

• 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

Question 11

symptoms in babies of surfactant deficiency

Answer 11

visibly distressed, tachypnoea, tachycardia, expiatory grunting, nasal flaring and chest wall recession

Question 12

what can increase lung compliance ?

Answer 12

age, emphysema, lung surfactant, loss of lung connective tissue, upright posture

Question 13

what can decrease lung compliance ?

Answer 13

pulmonary oedema, pulmonary fibrosis, pneumonectomy, kyphosis

Question 14

what is lung compliance ?

Answer 14

it is defined as the change in lung volume per unit change in airway pressure

Question 15

where are the peripheral chemoreceptors located ?

Answer 15

in the bifurcation of carotid arteries and arch of the aorta

Question 16

what can happen when a patient becomes hypercapnic ?

Answer 16

cerebral vasodilation