Neural control Flashcards
brainstem death
Heart may still beat, chest rises and falls but no brain life
Ondine’s curse
- Stop thinking about breathing means you die
- Impairs automation of breathing
- Phrenic nerve-diaphragm pacer possible treatment
Injury to S2-3-4
Dimisnhed cough reflex, no innervation to pelvic floor
T1 injury
Weak intercostal muscles (diminished respiration) and removes innervation to cardiovascular system
Damage to cervical spine
Loss of autonomic supply to blood vessels = decreased BP
C3-4-5 damage
No phrenic nerve = respiratory arrest
Pontine respiratory group
Located in pons
Pneumotaxic centre: ‘switch off’ button at the end of inspiration, takes input from lung stretch receptors
Apneustic centre: controls breathing depth
Ventral respiratory group
- Nucleus ambiguus
- Efferent role
- Forced inspiration and expiration
- botzinger complex: expiration
- Intermediate VRG: motor neurons for larynx, pharynx and trachea
- Rhythmic respiration initiated by re-Bötzinger complex
Dorsal respiratory group
- Nucleus solitarus
- Afferent - receives sensory info from CN9 and 10
- Quiet/passive inspiration
Vasoconstrictor area
Travels down spinal cord to constrict vessels increase HR and force
Vasodilator area
Inferior medulla
Inhibits vasoconstrictor centre
Sensory area
Tractus solitaries nucleus
Posteriolateral medulla
Circulatory signals from vagus and glossopharyngeal
Cardioacceleratory centre
Dorsal medulla
Sympathetic ns
Increases HR and force
Cardioinhibitory area
Nucleus ambiguous and dorsal nucleus
Parasympathetic NS
Reticular formation
- Area of brain that controls blood vessels
- PS impulses down vagus nerve and sympathetic via spinal cord (thoracolumbar spine)
Neural regulation of heart
- SAN (adjavent to SVC, lateral to RA) → AVN (posterior to tricuspid valve, delays impulse so atria can contract)
- Heart can beat by itself
- Sympathetic nerves increase the rate and strength of contraction
- Parsympathetic NS: CNs 3,7,9,10 and nerve roots S2-4
- Sympathetic nerves supply arteries - small arteries and arterioles, no p/s control of vessels
- cn1-4 from midbrain or above, 5-8 come out pons and 9-12 from medulla
CN10 testing
- Pt voice quality
- Elevation of soft palate and uvula when speaking
- Gag reflex motor
Cn10 motor supply
- Palate
- Pharynx
- Larynx
CN10 sensory supply
- Tympanic membrane
- External auditory canal
- Ear
CN10 course
- Medulla
- Jugular foramen
- In the cranium, auricular branch arises
- Right vagus nerve passes anterior to subclavian artery and posterior to sternoclavicular joint
- Left vagus nerve passes inferiorly between left common carotid and left subclavian arteries posterior to sternoclavicular joint
- In thorax, right forms posterior vagal trunk and left forms anterior vagal trunk
- In abdomen, trunks terminate by dividing into branches that supply oesophagus, stomach and bowels
CN9 testing
- Sensory part of gag reflex
- Ask to cough and swallow water
- Say aaaaahhhhh and look for uvula deviation
CN9 autonomic supply
Salivary glands
CN9 motor supply
Stylopharyngeus
CN9 sensory supply
Posterior third of tongue, pharynx, middle ear
