What are the different types of nerves in the PNS and how many?
- Cranial (12)
- Spinal (31)
What does the PNS control?
- cranial/spinal nerves
- ganglia
- enteric plexuses (GIT)
- other nerve plexuses
- sensory receptor
What is sciatica?
a range of symptoms including, extreme back pain, pain in lower limbs
What is the organisation of the PNS?
CNS - PNS
|
sensory - motor
|
somatic - autonomic
What is afferent?
- sensory
- nerves carry info from sensory receptors to CNS
- reflex
What is efferent?
- motor
- nerves carry info away from CNS to efferent organs
- parasympathetic and sympathetic
are somatic and autonomic voluntary or involuntary?
somatic - voluntary
autonomic - involuntary
what is the sympathetic nervous system?
fight or flight
what is the parasympathetic nervous system?
rest and digest
What are examples of parasympathetic ?
- pupil constriction
- slow heartbeat
- bladder constriction
- airway constriction
- saliva stimulation
What are examples of sympathetic?
- pupil dilation
- saliva inhibition
- airway dilation
- fast heartbeat
- bladder release
what are sensory neurons?
activated by external physical or chemical stimuli
what are motor neurons?
found in spinal cord that connect to organs, muscles, and different types of glands in the body
what are interneurons?
connect to motor neurons to sensory neurons, allowing signalling between the two
What are the three layers of connective tissue?
- endoneurium
- perineurium
- epineurium
What is endoneurium?
- Surround individual axons with a fascicle
- innermost tissue
What is perineurium?
- wraps around each fascicle
- Middle tissue
What is epineurium?
- encases all the fascicles to the whole nerve
- outer tissue
What and how many nerves are in the spinal cord?
- cervical - 8
- thoracic - 12
- lumbar - 5
- sacral - 5
- coccygeal - 1
total 31
What is dorsal rami?
- dorsal root - sensory (afferent)
- innervation to skin and back muscles
- smaller
What is ventral rami?
- ventral root - motor (efferent)
- innervation to the rest of the trunk and limbs
- larger
what is a nerve plexus?
multiple spinal nerves interacting together to perform a function
why is there several nerves working together to form a plexus
if 1 nerve is broken or damaged complete loss of function doesn’t occur
What are the 4 plexuses?
- cervical: under sternocleidomastoid (sternum-skull) muscle: innervates skin
- brachial: neck, shoulder: innervates upper limbs
- lumbar:innervates psoas muscle (attached to lumber spine-femur): innervates ab wall, anterior and medial thigh
- sacral: posterior lumbar plexus: innervates lower limbs, buttox and pelvis
