16.1 Flashcards
What is the conscious or subconscious awareness of changes in the external and internal environment ?
Sensation
What is the interpretation of sensations and is primarily a function of the cerebral cortex?
Perception
What is the uniqueness of each sensation; distinguishes one sensation from another (touch, pain, vision, hearing) called?
Sensory modality
each sensory neuron only carries one modality
What are the 2 classes of sensory of sensory modalities?
- GENERAL SENSES
- SPECIAL SENSES
What are the 2 types of general senses?
- Somatic senses
- Visceral senses
Which type of sense is this?
Tactile sensations (touch, pressure, vibration, itch, tickle)
Thermal sensation (heat or cold)
Pain sensations
Proprioreceptive receptors
Movements of limbs and head
Positions of limbs and body parts
Somatic senses
(Type of general senses)
What are visceral senses?
Provide information about conditions within internal organs (pressure, stretch, chemicals, nausea, hunger)
What are special senses?
Sensory modalities of smell, taste, vision, hearing, equilibrium or balance
Where does the process of sensation begin in?
A sensory receptor (can be either a specialized cell or the dendrites of a sensory neuron)
When does a sensory receptor respond?
Vigorously to a stimulus (change in environment)
Weakly or not at all to all other stimuli
What are free nerve endings?
Bare, not encapsulated dendrites
Lack any structural specializations that can be seen under a light microscope
What are encapsulated nerve endings?
Their dendrites are enclosed in a connective tissue capsule that has a distinctive microscopic structure (ex. Lamellated corpuscles)
What do the different types of capsules enhance in encapsulated nerve endings?
Enhance the sensitivity or specificity of the receptor
What type of nerve endings would receptors for pain, temperature, tickle, itch and some touch sensations? (Free nerve endings or encapsulated nerve endings)
Free nerve endings
What types of receptors would be encapsulated nerve endings? (Examples)
Receptors for other somatic and visceral sensations (such as pressure, vibration and some touch sensations)
What are seperate cells ?
Sensory receptors for some special senses are specialized special cells that synapse with sensory neurons
What are some examples of separate cells?
Hair cells for hearing and equilibrium in the inner ear, gustatory records for taste buds & photoreceptors in the retina of the eye for vision
Are olfactory receptors for the sense of smell separate cells?
No
They are located in olfactory cilia
(Hair like structures that project from the dendrite of an olfactory receptor cell)
A sensory experience that receptor responds to a stimulus be creating a graded potential called?
Receptor potential
In sensory receptors with free nerve endings or encapsulated nerve endings, how do the nerve impulses reach the CNS?
If the receptor potential is large enough to reach threshold it triggers one or more nerve impulses in the axon of the sensory neuron
The nerve impulses propagate along the axon into the CNS
In seperate cells, how do the nerve impulses reach the CNS?
The receptor potential triggers the release of a neurotransmitter through exocytosis of synaptic vesicles.
The neurotransmitters liberated from the synaptic vesicles diffuse across the synaptic cleft and produce a postsynaptic potential
If the threshold is reached the PSP will trigger one or more nerve impulses which propagate along the axon to the CNS
Receptors located at or near the external surface of the body; are senstive to stimuli originated outside the body & provide info about the external environment ?
Exteroreceptors
Which receptors would be involved with the sensation of hearing, vision, smell, taste, touch, pressure, vibration, temperature & pain
Exteroreceptors
What are interoreceptors? (Or visceroreceptors)
Located in the blood vessels, visceral organs, muscles and nervous system and monitor conditions in the internal environment. Nerve impulses produced by interoreceptors usually not consciously perceived - activation of strong stimuli may be felt as pain or pressure
Which receptors are located in the muscles, tendons, joints and inner ear. They provide information about body position, muscle length, tension and the position and movement of joints?
Proprioceptors
Which receptors are sensitive to mechanical stimuli such as the deformation, stretching or bending of cells. They provide sensations of touch, pressure, vibration, proprioception, heating & equilibrium and also monitor the stretching of blood vessels & internal organs?
Mechanoreceptors
What do thermoreceptors do?
Detect change in temperature
Which receptors respond to painful stimuli resulting from physical or chemical damage to tissue?
Nociceptors
What do chemoreceptors do?
Detect chemicals in the mouth (taste), nose (smell) and body fluids
What do osmorecptors do?
Detect the osmotic pressure of body fluids
A characteristic of most sensory receptors is adaptation. What does this mean?
The receptor potential decreases in amplitude during a maintained, constant stimulus.
This causes the frequent of nerve impulses in the sensory neuron to decrease.
The perception of a sensation may fade or disappear even though the stimulus persists
Ex. Stepping into a hot shower
Are receptors associated with vibration touch and smell rapidly adapting or slowly adapting receptors ?
Rapidly adapting receptors
