skin sense and hearing Flashcards
(30 cards)
the two main types of nerve endings in the skin?
Free endings: Not associated with any special structure.
Encapsulated endings: Associated with a special structure, such as the Pacinian or Meissner’s corpuscles.
Where are Pacinian corpuscles located, and what do they respond to?
Pacinian corpuscles are located in the deeper dermis or subcutaneous tissue and respond to changes in pressure at the surface of the skin.
Where are Meissner’s corpuscles located, and what do they detect?
Meissner’s corpuscles are located closer to the epidermis and are sensitive to light touch such as hair movement or itchiness
What are unipolar neurons, and what role do they play in skin sensation?
Unipolar neurons are specialised endings in the skin that convey sensory information to the spinal cord.
What are the characteristics of the receptive fields for different skin stimuli (touch, pain, temperature)?
Touch: Large, overlapping fields covering the skin.
Pain: Complex, with pain spots within a larger field sensitive to pain.
Temperature: Scattered across the skin, with some areas sensitive to hot and others to cold.
the pathway for sensory information from the skin to the brain?
Sensory information is sent to the somatosensory cortex in the parietal lobe via the spinal cord, where it is processed.
the role of the somatosensory cortex in processing skin sensations?
The somatosensory cortex processes sensory information such as touch, proprioception (position in space), nociception (pain), and temperature from the contralateral side of the body.
What is lateral inhibition, and how does it affect sensory processing?
Lateral inhibition sharpens sensory signals and removes noise during the relay process, helping to refine sensory input before it reaches the brain.
What are natural painkillers in the nervous system?
The nervous system contains endogenous painkillers, such as endorphins, which help modulate and reduce pain signals.
What are the main characteristics of sound pressure waves?
Frequency (in Hz): Experienced as pitch of sound, typically ranging from 20 Hz to 20,000 Hz in humans.
Intensity (in dB): Experienced as the loudness of sound.
What are the main parts of the auditory system?
External ear: Includes the auricle (pinna) and auditory canal.
Middle ear: Contains the ossicles (malleus, incus, and stapes).
Inner ear: Contains the cochlea and is responsible for both hearing and balance (equilibrium).
What role does the pinna (auricle) play in hearing?
The pinna helps capture sound waves and directs them into the auditory canal.
What are the ossicles, and what is their function in hearing?
The ossicles are three small bones (malleus, incus, and stapes) in the middle ear that transmit vibrations from the eardrum to the cochlea.
What is the function of the oval window in the inner ear?
The oval window transmits sound vibrations from the ossicles to the cochlea, setting the fluid inside the cochlea into motion.
Describe the structure of the cochlea.
The cochlea is a coiled structure shaped like a snail shell, filled with fluid that moves in response to sound vibrations.
What is the Organ of Corti, and what is its role in hearing?
The Organ of Corti is located within the cochlea and contains hair cells that transduce sound vibrations into nerve impulses. The hair cells bend in response to vibrations, allowing the brain to process sound.
How do hair cells in the cochlea detect sound?
Hair cells detect sound by bending their stereocilia in response to vibrations in the cochlear fluid. This bending triggers an electromechanical response that converts sound waves into electrical signals for the brain.
Where is the auditory cortex located, and what is its function?
The auditory cortex is located in the superior temporal gyrus of the temporal lobe and is responsible for processing auditory information.
What is the auditory pathway from the ear to the brain?
Sound is transmitted through the ear to the cochlea, then the auditory information is sent to the auditory cortex via the auditory nerve and brainstem pathways for processing.
How does the ear detect the pitch and loudness of sound?
Pitch is detected by the frequency of sound waves.
Loudness is determined by the intensity of sound waves.
How does the brain detect the origin of a sound?
The brain uses input from the pinna, slight head movements, and frequency analysis to localise the source of a sound.
What is the function of the round window in the cochlea?
The round window allows fluid displacement within the cochlea, enabling sound waves to travel through the cochlear chambers and stimulating the hair cells.
How does the ear detect the direction of sound?
The ear detects the direction of sound by analysing differences in the timing and intensity of sound waves that reach each ear, aided by the pinna and slight head movements.
What is the role of the auditory pathway in sound localisation?
The auditory pathway helps the brain interpret signals from both ears, allowing for the localisation of the sound’s origin based on differences in timing and intensity.
