Chapter 21: General and Special Senses Flashcards
What are General senses
Temperature
Pain
Touch
Pressure
Vibration
Proprioception
What are Special senses
Smell
Taste
Balance
Hearing
Vision
Sense Organs
- Eyes, Ears, and taste buds
What are Free nerve endings
Simplest receptors
What are large receptor fields
They have receptor fields spread far apart, which makes it difficult to localize a stimulus
What are small receptive fields
They have receptors close together, which makes it easy to localize a stimulus
What are Tonic receptors
They adapt very slowly or not at all
Examples:
Photoreceptors of the eye, Nociceptors and receptors that constantly monitor body position
What are Phasic receptors
Fast- adapting
Example: Touch and pressure receptors of the skin, smell of the nose
Classification of the general senses based on sensory location
Exteroceptors
- Provide information about the external environment
Proprioceptors
- Provide information about the position of the body
Interceptors
- Provide information about the inside of the body
Classification based on nature of the stimulus
Mechanoreceptors
- Sensitive to stretch, compression, twisting, or distortion of the cell membrane
Thermoreceptors
- Respond to changes in temperature
Nociceptors
- Respond to the sensation of pain
Chemoreceptors
- Monitor the chemical composition of body fluids
How many Mechanoreceptors do we have
Tactile receptors
Baroreceptors
Proprioceptors
Free nerve endings are
Common in the Dermis
Sensitive to light contact with the skin
Root hair plexus are
Associated with hair follicles
Monitors distortions and movement of hairs on the body surface
Tactile disc are
Free nerve endings synapse with Merkel cells
in the stratum basale of the epidermis
Sensitive to light contact with skin
What are Barorecptors
Stretch receptors that monitor changes in the stretch of organs due to pressure
What are proprioceptors
Monitor the position of joints
Thermoreceptors are
Found in the Dermis
Exist as free nerve endings
These are Phasic receptors
What is Gustation
It is taste, it provides information about foods and liquids that we consume
Taste Buds contain
Gustatory epithelial cells and basal cells
Gustatory primary taste sensations is sweet, salty, sour, bitter, and umami
What nerves are in Gustation (Taste)
Facial nerve (Vll) is 2/3 on the tongue
Then we have
Glossopharyngeal nerve (IX) posterior 3rd of the tongue
Taste information goes from the
Goes from our tongue–> thalamus—> gustatory cortex ( this cortex is is located in the cerebrum cortex)
If someone loses their sense of taste what could have been affected
Facial nerve (VII) damage
Glossopharyngeal nerve (IX) damage
Could indicate brain damage
Damage in the tongue or taste buds itself
What percentage of our sensory information goes to the thalamus
95% of it goes to our thalamus
5% that does NOT is Olfactory (l)
Where does smell go
Directly to the olfactory cortex
Vision sensation is detected by receptors for vision that are located on the posterior part of the eyeball. Those receptors are called
Photoreceptors
What do eyelashes prevent
Eyelashes prevent foreign objects from hitting the eyeball
Also have Root Hair Plexus which helps us with blinking reflex
What is Palpebral (Eyelid)
Helps to wash debris across the surface of our eye
What are lacrimal Apparatus
They are tears they are always active even if we are not crying, it is still producing tears to LUBRICATE the eyeball
What is the IRIS of the eye
The iris is the pigmented smooth muscle of the eye
Also has an opening in the center of the eye called the PUPIL
What is Pupil
It is a hole, a space in the eye that can change size when the Iris contracts or relaxed
When a pupil can enlarge that is called
Dilation
When a pupil can shrink
Constrict
If we are in a Bright place our pupils will
Constrict (Shrink)
If we are in a DARK place our pupils will
Dilate (Enlarge)
They will dilate so they can let the maximize amount of light inside our eye
The eye has 3 main layers
- Fibrous Layer
- Vascular Layer
- Inner Layer
What is the Fibrous layer made up of
It is made up of the Cornea and the Sclera
The cornea provides some degree of protection, it is also a point of attachment for the extrinsic eye muscle that moves the eye ball
What is the Vascular Layer
Deeper in our eyeball, has the Iris, also ahs the ciliary body smooth muscle that helps control the shape of the lenses
What means full of blood vessels, helps to nourish the Retina, and helps to cool down the eyeball
The Choroid
Located even deeper is the Inner layer which has the
Retina= has a pigmented layer and neural layer
Pigmented layers have a lot of Melanocytes involved in absorbing light
What are Rods (Night)
Rods are involved in black and white vision
- Helps better see things at night, let us see gray vision
What are cones (color) (HD)
Cones allow us to see color
Provide a high degree of resolution, sharpness of image
Utilized in the day light where we can see color
In the Retina we also find
Bipolar cells, Ganglion cells, Amacrine cells
All involved in processing visual information and refining the information before it is sent to the brain
Where we have the sharpest vision, the highest resolution possible is called
Fovea Centralis
What percentage of visual information goes to the Thalamus
75% goes to the thalamus, from there it goes to the primary visual cortex where we become conscious of the visual information
What percentage of our visual information goes to the mesome seprils
25% called Superior colliculus
The External ear contains the
Auricle, external acoustic meatus, and external side of tympanic membrane
