Section 4 Flashcards
Neural structures that detect information about the environment
Receptors
What are the four main types of receptors?
- Mechanoreceptors
- Thermoreceptors
- Nociceptors
- Chemoreceptors
What do mechanoreceptors respond to?
Structural distortion like:
- Stretching
- Skin distortion
- Vibration
- Hair movement
- Pressure
Where are mechanoreceptors located?
- Skin (cutaneous)
- Muscles (fleshy pt of m. spindle)
- Tendons (GTO)
- Ligaments (movement and position)
What temperature ranges do thermoreceptors respond to?
- Cold (15 - 30 degrees celsius)
2. Warm (30 - 42 degrees celsius)
Where are thermoreceptors located?
In the skin as free nerve endings
Receptors that respond to chemical mediators (as part of the inflammatory response), and other noxious stimuli (like tearing of tissue)
Nociceptors
Needed for healing since vasculature heals injuries
Inflammatory response
Where are nociceptors located?
- Skin
- Visceral organ walls
- Skeletal muscles
- Joint capsules
- Outer layer of the annulus fibrosis (disk)
- Periosteum of bone
Receptor _______ means the receptor produce or generates an AP; travels from the receptor toward the spinal cord
Activation
The ____________ causes receptor activation
Adequate stimulus
The specific form of energy that the receptor responds most easily to; takes the least amount of this energy for the receptor to produce an AP
Adequate stimulus (think eye = light energy, but can be activated by mechanical energy)
What is the adequate stimulus of mechanoreceptors?
Structural distortion and movement of the receptor
Mechanoreceptors give rise to the sense of:
- Proprioception (position)
2. Kinesthesia (movement)
Name the 3 specific stimuli of mechanoreceptors.
- Structural distortion like stretching
- Vibration
- Movement (hair follicle receptor)
Specialized mechanoreceptors signal the CNS about the position and movement of body parts, these receptors are known as ________.
Proprioceptors
Name the 3 types of proprioceptors.
- Muscle spindle
- Golgi Tendon Organ
- Joint receptors
What proprioceptor senses stretch?
Muscle spindles (primary afferent = rate of length change, senses it as it’s happening; secondary afferent = static length, long vs. short)
What proprioceptor senses muscle contraction tension?
GTO
What proprioceptor senses movement and pressure?
Joint receptors
Where are joint receptors located?
Ligaments and joint capsule
Term that refers to when a chemical causes a receptor to be more susceptible or responsive to future stimuli to fire AP; receptor becomes like a “hair-trigger”; not enough to fire AP
Sensitization
The stimulus that causes the nociceptor to immediately produce and action potential which is transmitted through the afferent axon to the spinal cord
Activation
The tendency for any nerve cell to fire an AP in response to future stimuli is known as ________
Sensitization of the neuron
A motor neuron is activated when it produces an _________
Action potential
Adaptation of a receptor means that during the application of the stimulus the receptor
gets used to the stimulus and turns-off (or more technically, stops firing APs)
A rapidly adapting receptor is also known as a _____ receptor
Phasic
A slowly adapting receptor is also known as a _____ receptor
Tonic
A sensory axon with all its receptor endings
Sensory unit
The region of skin innervated by the receptor endings is the sensory neuron’s ______________
Receptive or receptor field
True or False:
Receptors are voltage-gated channels
False; they are NOT voltage-gated channels
What are the stimulus energy types that are charged to electrical events in the receptor?
- Mechanical
- Electrical
- Chemical
Change of stimulus energy to electrical event is defined as ___________.
Sensory transduction
_______ potentials are proportional to the strength of the stimulus energy.
Generator or Receptor
If generator potentials sum or are great enough, they trigger ______ in the afferent axon
APs
In a rapidly adapting receptor, the receptor ________ while the stimulus remains
Turns off fast
In a slow adapting receptor the frequency (decreases/ increases) as receptor response decreases
Decreases
In a slow adapting receptor, the receptor _______ and the response decreases for the entire stimulus
Stays on
What substances cause activation in afferent fibers of nociceptors?
- Bradykinin
- Serotonin
- Potassium
- Histamine
What substances cause sensitization in afferent fibers of nociceptors?
- Prostoglandins
- Leukotrienes
- Hydrogen ions
- Substance P
- Hypoxia
Where are receptor fields located?
Skin or internal organ
A greater stimulus gives you a ______ graded potential, which results in a _______ frequency of action potential
Greater; higher
Frequency of action potentials are (inversely/directly) proportional to the amplitude of stimulus in CNS.
Directly
