2. Skin and Touch Flashcards
Where is the primary somatosensory cortex?
The SI region is behind the central sulcus
What is the homunculus?
A model where the size of the feature corresponds to the density of peripheral receptors thereby indicating its sensitivity.
What is the pathway for pain?
LEFT SPINE
LEFT MEDULLA
LEFT THALAMUS
What is the pathway for cutaneous receptors?
RIGHT SPINE
RIGHT MEDULLA
LEFT THALAMUS
3B REGION OF CORTEX
What is the pathway for proprioception from skeleto-muscular receptors?
RIGHT SPINE
RIGHT MEDULLA
LEFT THALAMUS
3A REGION OF CORTEX
What are special senses?
Highly specialised sensory organs and nerve endings occurring only in specific parts of the body. For example: vision, hearing, balance, olfaction, taste.
What are special senses?
Highly specialised sensory organs and nerve endings occurring only in specific parts of the body. For example: vision, hearing, balance, olfaction, taste.
What are generalised senses?
Found in many parts of the body, e.g. touch, temperature, pain, movement.
What are exteroceptors?
Found in the skin and respond to touch, pressure, vibration, temperature and pain.
What are proprioceptors?
Found in muscles, tendons, joins and sub-cutaneous tissues and vessels. They respond to position and movement, deep pressure and dull aching pain.
What are interoceptors?
Found in internal organs, they maintain homeostasis, organ function and respiration.
What are interoceptors?
Found in internal organs, they maintain homeostasis, organ function and respiration.
What are encapsulated cutaneous receptors?
Their function is to discriminate specific features of a stimulus. Therefore they respond to different vibrational frequencies and pressures, tickles and hairbending. They project to the spinal cord via A-beta sensory afferents which are myelinated and therefore fast.
What are un-encapsulated cutaneous receptors?
They are found in the superficial region of the skin and respond to temperature, pain and pressure. They project to the spinal cord via A-delta (myelinated) and C afferents (unmyelinated).
Which sensory afferents are associated with encapsulated cutaneoues receptors and are they myelinated or unmyelinated?
A-beta, myelinated, fast
Which sensory afferents are associated with un-encapsulated cutaneoues receptors and are they myelinated or unmyelinated?
A-delta, myelinated, fast
C, unmyelinated, slow
Describe glaborous skin?
Hairless, thick epidermis, sweat glands
Describe hairy skin?
Thin epidermis, sebaceous glands, hair follicle receptors, lower receptor density.
Describe hairy skin?
Thin epidermis, sebaceous glands, hair follicle receptors, lower receptor density.
Describe Meissner’s corpuscles?
Found between the dermal ridges of hairless skin only, have a small receptive field and adapt quickly, respond to stroking.
Describe Merkels’ disks
Attached to the dermis layer, hairless and hairy skin, have a small receptive field, adapt slowly, respond to pressure.
Describe Ruffini’s corpuscles
Found in the sub-cutaneous layer of hairy skin only, respond to skin-stretching, large receptive field, adapt slowly
Describe Pacinian corpuscles
The deepest cutaneous receptor, found in hairy and hairless skin, respond to vibration, have a large receptor field and adapt rapidly.
Which two cutaneous receptors are shallow
Meissner’s corpuscles and Merkel’s disks
Which two cutaneous receptors are deep
Pacinian corpuscles and Ruffini’s corpuscles
Which two cutaneous receptors adapt quickly
Meissner’s corpuscles and Pacinian corpuscles
Which two cutaneous receptors adapt slowly
Merkel’s disks and Ruffini’s endings
Which frequency are our fingertips most sensitive to
100-500 Hertz
