Chapter 15 Flashcards
Afferent division of Nervous System
receptors, sensory neurons and sensory pathways
SNS
motor neuron, motor pathways, and effectors
General Senses
sensitivity to temperature, pain, touch, pressure, vibration and proprioception
TPTPVP
Sensation
the arriving info in the form of an action potential; the greater the stimulus the higher the frequency of action potential
Preception
conscious awareness of sensation
special senses
olfaction, vision, gustation, hearing and equilibrium
List of stimuli or modality
light, sound, touch, dissolved chemicals and pressure
receptor specificity / free nerve endings
dendrites of neurons which are the simplest form of a receptor, not protected by accessory cells; extend through tissue like growing grass; typically not very specific
Receptors of the eyes
protected by accessory cells and connective tissue making them very specific because no other stimulus but light can get to them
Receptor Field
receptor cells monitor a specific area
sensory coding translates sensory info into patterns of ___ ____ can be: ___,___, or both depending on the complexity of the reception
action potential
tonic, phasic
Tonic Receptors
alway active and indicate the background level of stimulation, modifies action potentials when a stimulus changes in intensity; do not adapt well
Phasic Receptors
normally inactive but become active for a short time when a stimulus changes the environment they are monitoring; senses intensity and rate of change of a stimulus; highly adaptive
Adaptation
a reduction in sensitivity when there is constant stimulus that does not induce pain
Fast adapting receptors (phasic receptors)
provides peripheral adaptation …the receptor responds strongly at first but then its activity declines (temperature)
slow adapting recptors (tonic receptors)
have little peripheral adaptation. pain receptors are slow adapting reminds you of the pain so you can do something about it
central adaptation
further restricts the amount of detail arriving at the cerebral cortex beyond peripheral adaptation
Both peripheral and central adaptations are ___ responses that can induce ___ ____ responses (typically we are not aware of the stimulus or response)
subconscious
reflexive motor
The ___ ___ allow us to have control over whether or not we want to further heighten our awareness to a stimulus or ____ our awareness
higher centers
lower
Exteroceptors monitor
outside environment
proprioceptors monitor
positions of skeletal muscles and joints
interoceptors monitor
visceral organs
nociceptors
common locations
pain receptors
skin, joints, periosteum, walls of blood vessels
Fast pain - myelinated type ___ axon fibers carry ___ ___sensations quickly to the CNS; ____ pain and trigger ____ reflexes
A
Prickeling Pain
localized
somatic
Slow pain- type___ axons fibers carry ___ or ____ pain sensations to the ___; pain is in a general area. Sensitive to extreme: ___, ___ ___, ___ ____ (from damaged cells
C
burning, aching
temperature, mechanical damage, dissolved chemicals
Neurotransmitters affect pain levels (glutamate or substance P)
amounts of these neurotransmitters can determine the amount of pain perceived. May be out of proportion with painful stimuli
Neuromodulators affect pain levels, type of opioids: endorphins and enkephalins
inhibit activity along pain pathways by preventing the release of substance P so the pain perception decreases even though the stimulus is still there
Thermoreceptors common locations
dermis, skeletal muscle, liver and hypothalamus
Type of thermoreceptors
free nerve endings with cold receptors being 3 to 4 times more numerous than warm receptors; follow pain paths to the CNS; phasic
Mechanoreceptors
respond to stimuli that distorts the plasma membrane
Type of Mechanoreceptors
tactile, baroreceptors and proprioreceptors
Tactile receptors are sensitive to?
touch, pressure, vibration
Fine touch and pressure receptors
extremely sensitive to provide info on location, shape, size, texture and movement with small receptor field (fingers)
Crude touch and pressure receptors
large receptive field giving poor info on location and stimulus
Free Nerve Endings sensitive to?
touch and preasure
location of free nerve endings?
between epidermal cells and the cornea of the eye, tonic, receptor field small
Root Hair Plexus Nerve Endings sensitive to?
distortion of hair
Root hair plexus location
wrapped around root of hair, phasic and small receptor field
Tactile Discs (merkel discs) sensitive to
fine touch ad pressure (really sensitive)
Tactile disc location
stratum basale, tonic, small receptor field
Tactile corpuscles (meissner’s corpuscles) sensitive to?
fine touch and pressure, low vibrations
Tactile corpuscles located in
dermis of: eyelids, finger tips, lips, nipples and external genitalia
phasic
structure of tactile corpuscles
encapsulated
lamellated corpuscles (pacinian carpuscles) sensitive to?
deep pressure, vibrations
Lamellated located in?
dermis of: fingers, mammory glands, external genitalia, joint capsules and viscerally
phasic (because itss encapsulated)
Lamellated struture
concentric layers of collagen
Ruffini Corpuscles sensitive to
pressure, distortion of the skin, respond to twisting, tonic
Ruffini location?
reticular layer of dermis
Barorecptors
detect pressure changes in the walls of blood vessels and organs
Baroreceptors location
walls of distensible organs
Baroreceptor is a ___ receptor
free nerve ending
Baroreceptors are sensitive to ___ or ____ of ___ ___in the wall of an organ; moniters ___ ___ and ___ ___
coiling or expanding
elastic tissue
blood flow and blood pressure
Poprioceptors
monitor positions of joints and muscles
Golgi Tendon Organs
between muscle and its tendon, reacts to tension in the tendon to monitor muscle contraction
Receptors in joint capsules
free nerve ending detect pressure, tension and movement in joint
chemoreceptors
chemoreceptive neurons provide quick peripheral adaptation, sensitive to concentration of chemicals that dissolve in body fluids (id gasses, CO2)
Somatic Sensory Pathways
the first part of the tract name ids where the tract begins the last part=its destination
Somatic Sensory ascending tracts
from spinal chord to brain
phantom limb pain
painful sensations that aren’t really there due to sensory neurons or interneurons along the pathway
spino-thalamic pathway
crude touch and pressure in the anterior, pain and temperature in the lateral
Referred pain
pain felt in uninjured part of body but originates elsewhere…happen because visceral neurons can stimulate neurons in your spidalphelamic pathway
Posterior column pathway
fine touch, vibration, pressure and proprioceptions sensations
spinocerebellar pathway
proprioceptive input from golgi tendon organs, muscle spindles and joint capsules
Somatic Motor Pathways
sns controls voluntary motor movements
corticospinal pathway
voluntary control over skeletal muscles
medial pathway
subconscious regulation of balance and muscle tone, eye, head, neck and upper limb position when exposed to auditory or visual and reflexive activity
Lateral Pathway
subconscious regulation of upper limb muscle tone and movement
