examination questions for PHYSIOL 220/lecture on control of breathing
file: exam questions
DdeC
24 Sept. 2003

2004 
failure of respiration and death occurs after certain neck injuries because of
 a.  a fracture of one or more vetebrae in the cervical spine
 b.  interruption of spinal cord nerve fibres carrying lung inflation signals to the brain
 c.  tearing of large (jugular) veins draining blood from the head
>d.  interference with motor pathways from the brain to the phrenic motor nucleus 
 e.  damage to inspiratory muscles


2003
concerning the respiratory control system
    a. efferent pathways are motor to lung muscles and travel in the vagus (cranial X) and glossopharyngeal (cranial IX) nerves 
    b. the main control mechanism is located in the bronchial wall
    c. respiratory neurons in the medulla oblongata project directly to muscle of the diaphragm
    d. failure can occur after neck injury due to interruption of afferent (sensory) pathways
>   e. brainstem nuclei interact to produce an integrated rhythmic descending signal

2004
concerning the respiratory control system
    f.  the main control mechanism is located within the ventral horn of the spinal cord
    g.  a well-understood clock-like mechanism within the brainstem drives respiration
>   h.  afferent pathways travel to the brain via cranial nerves IX and X 
    i.  the main control mechanism is located in dendritic cells of the bronchial mucosal epithelium
    j.  its operation is involuntary because it is part of the autonomic nervous system

for 2004
the nerves supplying the diaphragm with motor signals
>	a.  are phrenic nerves
	b.  are splanchnic nerves
	c.  arise in the caudal medulla oblongata
	d.  are cranial nerves
	e.  have cell bodies in the lumbar enlargement of the spinal cord



2003
rhythmic ventilation of the lungs...
	  a. does not allow interruptions for cough or breath-holding
	  b. is independent of neuronal signals
>  	  c. feeds back to influence the next breath through the vagus nerve
	  d. normally requires voluntary commands from the premotor cortex
	  e. is unaffected by blood gas concentrations and pH of the blood



2003
energy expenditure on respiration...
	a. uses about three-quarters of the energy expended during quiet sleep in a thermo-neutral room
	b. is the main output variable optimised by the respiratory control system
	c. is unaffected in an individual by exercise or disease states
	d. is nil, because ventilation depends on passive diffusion of gases
> 	e. is minimised by the respiratory control system both at rest and during exercise

15 - 20 minute short answer essay question

2003
Describe the layout of the respiratory control system mentioning the location of the information processing centre, its efferent pathways, the effector mechanisms, (examples of) feedback sensors, and of afferent (feedback) pathways. Is the respiratory system under voluntary or automatic control?