Physiology Quiz: Somato-Sensation and Receptors

Somato-Sensation

• Somato-sensation is the physiological process by which neural substrates are activated by physical stimuli, resulting in the perception of touch, pressure, pain, etc.

Receptors and Acuity

• Acuity is negatively correlated with the amount of convergence in ascending pathways, size of the receptive field, and overlap with adjacent receptive fields.
• Response is highest at the center of the receptive field since receptor density is the highest there.
• Lateral inhibition increases acuity by inhibiting information from neurons at the edge of a stimulus.

Receptor Types

• Rapid adapting receptors respond rapidly at the onset of a stimulus but slow down or stop firing during the remainder of a stimulus, important for signaling rapid change.
• Slow adapting receptors maintain their response at or near the initial level of firing through the duration of the stimulus, important for signaling slow changes.

Vision

• Vision is the special sense of sight that is based on the transduction of light stimuli received through the eyes.
• The visual system is the primary receiver of sensory information to maintain postural balance, working together with the vestibular system.

Hearing

• Hearing is the process by which the ear transforms sound vibrations in the external environment into nerve impulses that are conveyed to the brain, where they are interpreted as sounds.
• The process involves the outer ear, eardrum, ossicles, and inner ear, where sound waves are converted into electrical impulses.

Proprioception

• Proprioceptors embedded in muscles and tendons inform us of the degree to which muscles are stretched, amount of tension in tendons, and position of joints.

Walking

• Walking is a complex process that involves various mechanisms and functions of the body coordinated by the brain.
• The muscular system, skeletal system, and nervous system are involved in walking, with the brain playing a crucial role in initiating and controlling movement.

Role of Brain in Walking

• The motor cortex initiates and controls voluntary movements, including walking, sending signals to muscles to contract and relax in a coordinated manner.
• The cerebellum plays a crucial role in balance coordination and motor learning, contributing to smooth and efficient walking.
• The brainstem regulates basic motor functions and reflexes involved in walking, such as maintaining body posture and adjusting gait in response to changes in terrain.

Consciousness and Behavior

• Consciousness refers to the state of being aware of and able to perceive one's thoughts, feelings, and surroundings.
• Behavior refers to the actions or reactions exhibited by an individual in response to internal or external stimuli.

States of Consciousness

• Consciousness refers to our subjective experience of the world around us and our inner mental states, including normal waking state, sleep, dreaming, and meditation.

Association Cortex and Perceptual Processing

• The association cortex is a part of the cerebral cortex that performs complex cognitive functions, including recognition of shape, form, textures of objects, awareness of body image, and relationships of body parts.
• Perceptual processing involves the evaluation and interpretation of sensory stimuli, which can become adapted and cease to be remarkable over time.

Primary Sensory Coding

• Sensory coding involves the coding of 4 aspects of a stimulus: stimulus type (modality), stimulus intensity, stimulus location, and duration.
• Stimulus type is coded by the type of receptor activated, intensity by the magnitude of the receptor potential, and location by the site of the stimulated receptor.