The Peripheral Nervous System

1. The Peripheral Nervous System PNS – yep it sounds like your saying penis If you liked that one you will love the ANS -anus

2. Central vs Peripheral • Central NS is includes the brain and the spine • PeripheralNS includes everything outside of the CNS

3. The Nervous System

4. The Somatic Branch • The word soma means body! • Motorinformation from the brain • Voluntary movement • Sensory information to the brain • Sense data from skin, body etc. • Afferent – to the brain • Efferent – from the brain • SAME – sensory nerves are afferent, motor nerves are efferent

5. The Autonomic Branch • Connected to internal organs, not consciously controlled. Keeps us alive – automatically. • Sympathetic branch controls arousal, fight or flight response / fires us up. Release of adrenaline, heart up, breathing up etc. • Parasympatheticcalms back down, keeps at stable level. Digestion resting etc.

7. Autonomic function – sympathetic and parasympathetic

8. Living while brain dead… thanks to the PNS • Carol Ann Quinlan • April 1975 became unconscious after coming home from a party • Consumed sedatives and alcohol • stopped breathing twice for 15 minutes or more • Went into a persistent vegetative state • Kept alive on a ventilator for several months • Removed from mechanical ventilation during 1976 • Persistent vegetative state for almost a decade until her death from pneumonia in 1985. • Autonomic branch of the ANS kept her ‘alive’

9. Living while brain dead… thanks to the PNS • Terri Schiavo • Heart attack on February 25, 1990 • massive brain damage due to lack of oxygen • two and a half months in a coma • Diagnosed as a persistent vegetative state • Kept alive via a feeding tube • Court case lased 7 years before her husband won the right to have her feeding tube disconnected • Terrie died on March 31 2005 • The Autonomic branch of the ANS kept her ‘alive’ Left: CT scan of normal brain; Right: Schiavo's 2002 CT scan, showing loss of brain tissue. The black area is liquid, The small white piece in the right image is the Thalamic stimulator implanted in her brain to help suppress tremors and spasms

10. Persistent Vegetative states • Patients in a vegetative state may have ‘awoken’ from a coma • Patient has NOT regained awareness • Patients can open their eyelids occasionally and demonstrate sleep-wake cycles • Completely lack cognitive function • diagnosis, made after numerous neurological and other tests, that due to extensive and irrevocable brain damage a patient is highly unlikelyever to achieve higher functions above a vegetative state

11. What can a person in PVS do? • PVS patients' eyes might be in a relatively fixed position, or track moving objects, or move in a disconjugate (i.e. completely unsynchronized) manner • They may experience sleep-wake cycles, or be in a state of chronic wakefulness • They may exhibit some behaviours that can be construed as arising from partial consciousness, such as grinding their teeth, swallowing, smiling, shedding tears, grunting, moaning, or screaming without any apparent external stimulus • Individuals in PVS are seldom on any life-sustaining equipment other than a feeding tube because the brainstem, the centre of vegetative functions (such as heart rate and rhythm, respiration, and gastrointestinal activity) is relatively intact

12. Fight or Flight • It is sympathetic arousal! • In response to a real or imagined threat • Physical or psychological danger

13. Things to do • Learning activities 5.1, 5.3, 5.5, 5.6 • Sympathetic arousal handout