Senses And Perceptions 2 Flashcards
What are the receptor endings on the peripheral of the skin
Free nerve endings
They are unspecialised
Give some examples of mechanoreceptors
- meissners corpuscle
- meckels disc
- hair follicle receptors
- pacunian corpuscle
- ruffini endings
Describe peripheral nerve structure
Contain sensory neurons (afferents) and motor neurons (efferents)
What is epineurium
Tough connective tissue provides mechanical protection, covers each individual fascicle in peripheral nerves
What is a fascicle
Each individual axon
What surrounds the peripheral nerve
Perineurium
Describe the vascular supply for peripheral nerves
Many blood vessels requires an adequate blood supply
Describe alpha axons
Diameter - 13-20 (um)
Speed - 80-120 (m/sec)
Sensory receptors - proprioceptors of skeletal muscle
Conduct very fast
Describe beta axons
- diameter 6-12 (um)
- speed - 35-75 (m/sec)
- sensory receptors - mechanoreceptors of skin
Conduct action potentials fats but not as fast as alpha
Describe delta axons
Thin myelin sheath
The action potential moves slowly
5-30m/sec
Pain temperature
Describe the C axon
Unmyelinated
0.5m/sec
Temperature, pain, itch
What brain matter is in the centre of the brain
Central is grey matter
What matter is found on the outside of the spinal cord
White matter
What are sensory afferents
The sensory nerve that travels from the stimuli to the dorsal horn
What are the motor efferents
The motor stimuli from the ventral horn to the muscle
What goes into the spinal cord
Sensory afferents
What comes out of the spinal cord
Motor efferents
What is the dermatome map
The map of the skin, what parts of the skin is innervated by which part of the spinal cord
What are the branches of the trigeminal nerve
Opthalmic and maxillary - sensory branches
Mandibular - mixed sensory and motor
Where is the receptive field represented
In the cortex
What body regions have high cortical representation
Body regions with high sensory innervation (high density of receptor endings and small overlapping receptive fields) have greater cortical representation
What is the dorsal root
The dorsal root ganglia to the dorsal horn
What are the sensory branches of the trigeminal nerve
Ophthalmic and maxillary branch
What is the mixed sensory and motor region of the trigeminal nerve
Mandibular branch
What neurons are involved in the sensory pathway
Neuron 1- primary sensory neuron (periphery)
Neuron 2 - secondary sensory neuron (spinal cord/brainstem)
Neuron 3- tertiary sensory neuron (thalamus)
Describe the mechanosenation pathway
Neuron 1 - from hand (stimulus) to medulla (brainstem)
Neuron 2 - at medulla switches to the other side and goes to the thalamus
Neuron 3 - synapses at the second neuron and sends information to the cortex, where the mapping of the body is
Describe the nociception pathway
Neuron 1 - stimulates pain receptor, pain synapses when it enters the spinal cord rather than at the medulla, meaning it switches sides here
Neuron 2- bypasses the brainstem, must go to the thalamus and synapses with the 3rd neuron here
Neuron 3 - travels to the cortex and gains a response, this is where you will become aware of the pain
What is the spinal nucleus
Sensory tract located in the lateral medulla, principle function id relaying temp and sensation to the face
