Week 21: (C.1) Neuroanatomy & Neurophysiology of breathing Flashcards
Anatomy of the respiratory centre
Are breathing movements spontaneous in breathing?
NO
Skeletal muscles which control breathing require neural input
Isa breathing input voluntary or involuntary?
Neural input can be involuntary (tidal breathing) and voluntary (IRV, ERV, breathing frequency)
What do chemo-receptive inputs monitor?
plasma and cerebral spinal fluid composition to maintain ventilatory homeostasis (eg over-ride voluntary breath hold)
What are the 2 respiratory control centres in the brain?
Pons respirator centre
Medullary respiratory centre
What is a part of the pons respiratory centre?
Pneumotaxic centre
Apneustic centre
What is a part of the medullary respiratory centre?
Pre-Bötzinger complex
Dorsal Respiratory Group (DRG)
Ventral Respiratory
Group (VRG)
Where is the central pattern generator located?
brainstem under the hypothalamus
What is a central pattern generator?
biological neural circuits that produce rhythmic outputs in the absence of rhythmic input
What provide input into the central pattern generator?
central chemo-receptor (CCR) (involuntary) Sensory migration (voluntary)
What neurones are there in the spine that are related to breathing?
ventral respiratory group
dorsal respiratory group
What are the inputs to the DRG and the VRG during inspiratory output?
BOTH - phrenic (diaphragm)
BOTH - spinal nerves (external inter-costal muscles)
VRG - CN IX, X, V, VII, XI
What are the inputs to the DRG and VRG during expiratory output?
- ONLY VRG neurones
- VRG - Spinal nerves (internal intercostal and abdominal muscles)
What is a summary of roles of the dorsal respiratory group?
>Inspiratory control >Located within the Nucleus tractus solitarius and is >dorsal to the VRG >Site of sensory information input >Site of central chemoreceptor input >Some premotor neurons
Where is the DRG located?
Located within the Nucleus tractus solitarius and is dorsal to the VRG
What is a summary of roles of the VRG?
Spans 3 regions in the medulla
What regions does the VRG span?
Rostral
Intermediate
Caudal
What is the function of the rostral regions?
expiration control (Botzinger complex)
What is the function of the intermediate regions?
Inspiration Control mediated through Pre-Bötzinger complex - thought to be site of Respiratory Pattern Generator
Is the DRG involved in inspiratory or expiratory control?
inspiratory
What is the function of the caudal region?
expiration control
What are the inspiratory muscles? (top to bottom of rib)
Sternocleidomastoid Scalenes External Intercostals Parasternal Intercostals Diaphragm
What are the expiratory muscles? (top to bottom of rib)
internal intercostals external abdominal oblique internal abdominal onlique transverse abdominalis rectus abdominis
What innervates the peripheral chemoreceptor feedback?
- hypoglessal nerve
- Laryngeal nerve
- Carotid Sinus nerve
What nerves innervate the breathing frequency volume?
Vagus nerve
What nerves innervate the respiratory muscles?
intercostal nerves
What nerves innervate the diaphragm inspiration control?
Phrenic nerve
Why would we need a forced expiration?
exercise, voluntary (cough, sneeze, defaecation)
What motorneurons are important in the opening and closing of the glottis?
cranial motorneurons
What is the pharynx and larynx?
> Pharynx is a part of an alimentary canal, which extends from the nasal cavity and mouth which extends from the nasal cavity and mouth to the larynx and the esophagus
Larynx is the upper portion of the trachea.
Both air and food pass through the pharynx.
What are the cranial motorneurones role?
lower motor neurons control movements of the eyes, face and tongue, and contribute to chewing, swallowing and vocalization.
What is the glottis?
the part of the larynx consisting of the vocal cords and the opening between them. It affects voice modulation through expansion or contraction.
How do the cranial motorneurones effect the upper airways?
cranial motorneurones are important for opening/closing glottis, affecting upper airway diameter, flaring nostrils etc