Sensory System Flashcards
What are different ways that the senses can be classified into types?
-General senses or special senses or; -Encapsulated or unencapsulated.
Where is a sensation actually perceived?
Brain
What is the function of proprioceptor?
PROVIDE INFORMATION ON POSITION and MOVEMENT of BODY PARTS as well as the length and the extent of contraction and tension in our muscles.
What is two-point discrimination?
The ability to distinguish one touch stimulus from two is called two-point discrimination.
Neurological test - involves simultaneously touching two points over one area to determine whether the ability to feel the two separate stimuli is present.
What are the three layers of the eyeball?
Sclera, choroid, and retina
What is the function of melanin in the choroid?
the choroid contains large amount of the dark pigment melanin.
This almost-black layer helps PREVENTS SCATTERING OF INCOMING LIGHT RAYS, which could make it hard for the eye to focus on an image.
What involuntary muscle structure changes the size of the pupil?
Iris
What involuntary muscle structure focuses the lens on close objects?
Ciliary muscle
What are the humors of the eye?
Aqueous: Watery fluid in front of the lens
Vitreous: Jellylike fluid behind the lens
How are rods and cones used in vision?
Rods are the receptors for night vision, and cones are the receptors for daytime vision.
What is the function of the ganglion cells of the retina?
Information from ganglion cells helps the body DETERMINE whether it is DAY or NIGHT, as well as the LEVEL OF MOONLIGHT (monthly phases). This helps our body’s internal clock mechanisms synchronize themselves to the daily, monthly, and seasonal rhythms of our external environment.
What senses are detected in the ear?
Hearing, equilibrium, and balance
Describe the three main parts of the ear?
- External ear (auricle and external auditory canal);
- Middle ear (contains the malleus, incus, and stapes);
- Inner ear (bony labyrinth filled with fluid; divided into the vestibule, semicircular canals, and cochlea)
What ear structure vibrates when sound waves travel through the acoustic canal?
Tympanic membrane
How do the ossicles work in helping a person to hear?
Sound waves cause eardrum vibration, which is transmitted and AMPLIFIED by the ear ossicles as it passes through the middle ear.
Where are the receptor cells for hearing located?
Hair cells in the organ of Corti
Where are the receptor cells for equilibrium located?
The vestibule and the three semicircular canals.
Name the general senses found in the skin or subcutaneous tissue and list the type of stimuli to which each of them responds. Identify which of these general senses are unencapsulated.
All are Encapsulated specialized receptors that respond to pain, touch, tickle, and temperature;
(1) TACTILE (Meissner corpuscles)
- close to skin surface (fingertips and lips)
- detect light touch and vibration;
(2) BULBOUS (Ruffini corpuscles)
- subcutaneous tissue of fingers and dermis
- detect touch and pressure;
(3) LAMELLAR (Pacini corpuscles)
- found deep in the dermis (subcutaneous tissue around joints, mammy glands and genitals)
- detect pressure and vibration
(4) BULBOID (Krause corpuscles)
- dermis and subcutaneous tissue (mucosa of lips, eyelids and genitals)
- detect touch and cold
Name the two types of proprioceptors and give the location and general sense of each.
Golgi Tendon Receptor - junction of muscles and tendons
- sense the contraction and extension of tendons (sense muscle tension)
Muscle Spindle - skeletal muscles
- sense change in muscle length
Explain how the iris changes the size of the pupil.
It contains two types of muscle fibers - iris dilator and iris sphincter muscles
The iris dilator muscle opens your pupil from the inside out
The iris sphincter is a circular muscle that controls closing your pupil
Explain how the ciliary muscle allows the eye to focus on near and far objects.
Muscle fibres in the ciliary body help the eye to focus on near or far objects by changing the shape of the lens
Define presbyopia, and describe the common cause of this condition.
is a refractive error that occurs when the lens of the eye loses its elasticity and becomes less flexible over time
- Makes it difficult to see things close-up
- occurs with aging
Define glaucoma, and describe its cause.
A chronic eye disease that occurs when the optic nerve is damaged
Due to increased pressure in the eye
Describe cataracts, how they are caused, and what can be done to prevent them.
- Clouding of the eye’s lens that can cause blurry or hazy vision
- Caused by ultraviolet light from the sun
- Wear sunglasses
Briefly describe the structure of the external ear.
Auricle (PINNA) - collect sound waves, focus into acoustic canal
External Acoustic canal - contains ceruminous glands
Ends at tympanic membrane (eardrum)
Explain how sound waves are transmitted through the middle ear.
Enter external ear through canal
Tympanic membrane to vibrate, causing malleus, incus and stapes to vibrate against oval window causing fluid to
Sound waves strike the TYMPANIC MEMBRANE (eardrum) to vibrate, that movement is transmitted and amplified by the ear OSSICLES as it passes through the MIDDLE ear. Movement of the STAPES against the oval window causes movement of fluid in the INNER ear.
Explain how the sense of smell is stimulated.
Olfactory Receptors are stimulated by odor-causing chemicals
That nerve impulse travels through the olfactory neurons in the olfactory bulb and cranial nerve 1
It then enters the thalamic and olfactory centers of the brain,
Where the nervous impulses are interpreted as specific odors
