Perception Flashcards
What three sections is the ear divided into?
The outer ear, the middle ear and the inner ear
What structures make up the outer ear?
The auricle (pinna), external acoustic meatus (ear canal) and the lateral surface of the tympanic membrane (ear drum).
What is the main function of the outer ear?
To conduct sound waves to the tympanic membrane
What are the main structures of the middle ear?
Main structures are three tiny bones:
- Malleus (hammer)
- Incus (anvil)
- Stapes (stirrup)
How do the bones of the middle ear (ossicles) facilitate hearing?
They are arranged in a way to transmit sound vibrations from the tympanic membrane, one to the other and finally to the oval window and then into the fluid filled inner ear.
What is the Eustachian tube?
A tube that connects the middle ear with the nasopharynx. Normally closed but opens with yawning and swallowing.
What are the functions of the Eustachian tube?
Provides the means of equalizing the pressure in the middle ear with atmospheric pressure
Equal air pressure on both sides of the tympanic membrane ensures that sound transmission is not reduced.
Also avoids ruptured of the tympanic membrane during air travel.
Ear problems are common during infancy. Why is this?
Infant’s eustachian tube shorter, wider, positioned more horizontal
Easier pathway for pathogens from nasopharynx to migrate to middle ear.
What makes up the inner ear?
The inner ear contains a system of interconnecting membranous channels. Divided into:
-Cochlea
-Vestibule
-Semi-circular canals
Each is filled with a fluid called endolymph
What happens in the cochlea?
The cochlea is the receptor organ of hearing where transduction of sound stimuli occurs.
This occurs in the organ of Corti, a spiral organ located in the cochlea containing receptor cells.
Impulses are then transmitted through afferent fibres via the auditory nerve to the brain.
What types of deafness or hearing impairment are there?
- Conductive Hearing Loss – mechanical dysfunction of the outer or middle ear. Partial loss of hearing, auditory nerve is normal.
- Sensorineural Hearing loss – dysfunction with the inner ear and/or cranial nerve V111 or the auditory area of the cerebral cortex.
- Mixed hearing loss is a combination of both.
What causes hearing loss in children?
Causes: -Genetic -Intrauterine (infections, maternal drugs & alcohol) -Birth asphysia -Prematurity -Severe jaundice -Infections – meningitis, septicaemia -Head injury Conductive hearing loss due to glue ear is most common.
What is the role of the inner ear in balance?
Vestibules (static equilibrium), and semicircular canals (dynamic equilibrium) located in the inner ear are responsible for balance.
They sense head motion and acceleration. They also maintain and assist recovery of a stable body and head position.
Vertigo, nausea and vomiting can occur when impulses from vestibular structures “disagree” with what we see.
How does age affect hearing?
- Cilia lines ear canal becomes coarse and stiff and impedes sound waves.
- Impacted drier cerumen causes hearing loss.
- Presbycusis – gradual sensorineural hearing loss in aging adult caused by nerve degeneration >50 years.
- After >70 years auditory reaction takes a longer time to process sensory input and respond.
What is the definition of pain?
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
Pain is whatever the person experiencing the pain says it is, existing whenever he/she says it does
What are the categories of pain?
- Acute
- Nociceptive (No-sea-septive)
- Chronic
- Neuropathic
What is acute pain?
- Sudden onset, eventually resolves & heals, treatment involves action followed by management
- A protective mechanism
- A response to internal or external stimuli
i. e. Acute abdominal pain or hot frying pan handle
What is nociceptive pain? What is somatic and visceral?
The sensory response to noxious stimuli that implies damage or potential damage to somatic or visceral tissues
Somatic: Bone & soft tissue
Visceral: Organs found in GI tract & Pancreas: Can be caused by an obstruction
What are the phases of nociception?
Transduction, Conduction & Transmission
Begins when nerve endings (nociceptors) of C fibres and A-delta fibres in response to noxious stimuli
C fibre: dull, burning or aching (slow)
A-delta fibres: sharp, stinging (fast)
What is chronic pain?
Prolonged, intensity varies, lasts >6mths, associated with depression, loss of work, fatigue, anger, frustration. Management is important
What is neuropathic pain?
Centrally generated from the central nervous system (phantom pain) or peripherally generated (neuropathies: diabetes, nerve entrapment)