Topic 11- Cutaneous Senses Flashcards
What is proprioception?
Sense of our body’s position and the movement of our limbs
What complications occurred to Ian Waterman?
What system did this breakdown?
What happened to his body?
What did he rely on?
4pts
- Complications from a viral infection that damaged sensory neurons from the neck down - Breakdown of the somatosensory system
- Lost of proprioception and sense of touch
- Couldn’t feel his body; inappropriate amounts of force
- Relied on their vision
What are some of the components of the somatosensory system?
3pts
- Cutaneous senses
- Proprioception
- Vestibular system
What does the cutaneous senses allow us to perceive?
Ability to perceive sensations based on the stimulation of receptors in the skin
Heaviest organ in humans, and one of the largest by total surface area.
What am I?
The skin
What are the two types of skin?
Mention the following for each type:
- Presence of hair follicles
- Sensitivity
- Examples
8pts
Hairy skin:
- Presence of hair follicles
- Typically less sensitive to touch
- Ex- arms, legs, back
Glabrous skin:
- Does not have hair follicles; contains larger number of sensory receptors
- Areas more sensitive to touch
- Ex- palms, feet, lips, tongue
What are the 3 layers of the skin?
Epidermis –> mechanoreceptors –> Dermis
Epidermis: Outer layer of the skin- On the surface of the skin is a tough layer of dead skin cells
Mechanoreceptors: Receptors that respond to mechanical stimulation of the skin (pressure, vibration, stretching)
What are the two tactile perceptions located close to the surface of the skin, near the epidermis- mechanoreceptors?
Is the receptive field smaller or larger?
7pts
–> Receptive field is smaller
- Merkel receptors:
- Fires continuously, as long as the stimulus remains present
- Is associated with the perception of fine details and shape - Meissner corpuscles:
- Fires only when the stimulus is first applied, and again when it is removed
- Associated with perceiving motion across the skin
What are the two mechanoreceptors deeper in the skin?
Are the receptive fields smaller or larger?
7pts
–> Larger receptive field
Ruffini cylinders:
- Fires continuously, as long the stimulus remains present
- Associated with the perception of skin stretching
Pacinian corpuscles:
- Fires only when the stimulus is first applied and then when it is removed
- Is associated with perceiving vibrations and textures (particularly fine textures)
What is a unique characteristics of the somatosensory system ?
2pts
- The sensory receptors are distributed across the entire body
- Therefore, signals need to travel long distances to reach the brain
31 segments of the spinal cord, each of which receives signals through a bundle of fibers called the BLANK
After the signals enter the spinal cord, where are the signals sent? What signals do they carry ?
5pts
- Dorsal root
The signals are sent to the brain along two major pathways:
- The medial lemniscal pathway:
–> carries signals for proprioception, pressure and fine touch
- The spinothalamic pathway:
–> carries signals for pain, irritation, itchniness and temperature
Which other area of the brain does it pass through and where does it end?
2pts
- It also passes through the thalamus
- Ends at the contralateral primary somatosensory cortex (S1)
What is an important characteristic of S1 in terms of its organization?
3pts
- It is organized into a map that corresponds to the different locations on the body
- Lower portion of S1: sensations on the lips and face
- Higher portion of S1: sensations on the hands and feet
What do the larger areas of the homunculus structure mean?
These are the areas we typically use to explore the environment
What does our ability to actually identify patterns through perception depend on?
Tactile detail perception
