29 Questions
What is the function of the receptors found in the deeper layer of the skin, deeper internal tissues and joints?
Detecting heavy prolonged touch and pressure
What type of fibers are responsible for carrying pain, itch, temperature, and crude touch sensations?
Type C Fibers
Which type of receptors are found in the hairy parts of the skin, fingertips, and other tissues?
Iggo Dome Receptors
What is the function of the receptors found in the non-hairy parts of the skin, such as the lip and fingertips?
Detecting touch and low frequency vibration
Which type of fibers are responsible for carrying temperature, crude touch, and pricking pain sensations?
Aδ Fibers
What is the function of the receptors found around the base of the hair?
Stimulated by slight movement of any hair on the body
What type of stimulus is required to cause deformation of the Pacinian Corpuscle's capsule?
Mechanical stimulus
What is the result of the receptor potential rising above the threshold for eliciting action potentials in the nerve fiber?
An increase in action potential frequency
What type of nerve fibers are involved in the transmission of vibration senses?
Type Aβ Fibers
What is the minimum number of input terminals required to discharge almost simultaneously to cause excitation of a postsynaptic neuron?
Six terminals
What is the result of further Na+ influx in the generation of the receptor potential?
Depolarization
What is the role of the receptor potential in the sensory process?
To generate action potentials in the nerve fiber
What is the relationship between the diameter of a nerve fiber and its conducting velocity?
The larger the diameter, the greater the conducting velocity
What is the range of conducting velocities in nerve fibers?
0.5 to 120 m/sec
What is the maximum amplitude of a Receptor Potential?
100 mV
What is the characteristic of a Tonic Response in sensory receptors?
The generator potential is proportional to the intensity of the stimulus
What is the common feature of all sensory receptors?
They change the membrane electrical potential in response to a stimulus
What type of stimulus is received by Neuron A from Input Fiber 1?
Suprathreshold stimulus
What is the effect of the discharge of terminals from Input Fiber 1 on Neurons B and C?
They are more likely to be excited
What is the term for signals from multiple inputs uniting to excite a single neuron?
Convergence
What type of convergence occurs when multiple terminals from a single incoming fiber tract terminate on the same neuron?
Convergence from a single source
What is the result of convergence from multiple sources?
A summated effect of all the different types of information
What is the term for the stimulus that is above the threshold required for excitation?
Suprathreshold stimulus
What happens to the number of sensory receptors activated in a sensory unit as the intensity of the stimulus increases?
The number of sensory receptors activated increases
What is the relationship between the area of the receptive field and the density of receptors in the region?
The area of the receptive field is inversely proportional to the density of receptors
What is the effect of an excitatory receptor field on the firing rate of a sensory neuron?
It increases the firing rate of the sensory neuron
What is the characteristic of sensory receptors that are activated by weak stimuli?
They have a low threshold
What is the relationship between the intensity of the stimulus and the change in stimulus strength required to cause a change in the body's response?
The greater the intensity of the stimulus, the greater the change in stimulus strength required
What can be inferred about the density of receptors in the tip of the hand?
The density of receptors is increased
Study Notes
Receptive Fields
- The body can detect small changes in stimulus strength at low intensity, but at high intensity, the change in stimulus strength must be much greater to cause a change.
- The number of sensory receptors activated in a sensory unit is proportionate to the intensity of the stimulus.
- Weak stimuli activate lower threshold receptors, while strong stimuli activate higher threshold receptors.
Receptor Fields
- The area of skin whose stimulation results in changes in the firing rate of the neuron varies inversely with the density of receptors in the region.
- Excitatory receptor fields increase the firing rate of sensory neurons, while inhibitory receptor fields decrease the firing rate.
- The greater the receptive field, the lower the density of receptors.
Pacinian Corpuscle
- A mechanical stimulus deforms the capsule of the Pacinian corpuscle, causing the opening of Na+ channels and depolarization.
- This leads to the generation of an action potential that is conducted along the nerve fiber.
Receptor Potential
- The generation of the receptor potential causes the opening of Na+ channels, Na+ influx, and depolarization.
- The receptor potential rises above the threshold for eliciting action potentials in the nerve fiber attached to the receptor, causing action potentials to occur.
Nervous System Organization
- The nervous system is organized into different types of receptors, including olfactory receptors, taste receptors, osmoreceptors, and more.
- Each type of receptor is responsible for detecting specific stimuli, such as temperature, pain, touch, and pressure.
Sensory Receptors
- There are two types of sensory receptors: encapsulated (e.g. Meissner’s corpuscles, Pacinian corpuscles) and unencapsulated (e.g. free nerve endings, Merkel’s discs).
- Receptors can detect different stimuli, including touch, pressure, temperature, pain, and itch.
- Each type of receptor is responsible for transmitting specific information to the CNS.
Nerve Fibers
- There are different types of nerve fibers, including Aα, Aβ, Aδ, and C fibers, each with different functions and conduction velocities.
- The sizes, velocities of conduction, and functions of the different nerve fiber types vary.
- The larger the diameter of the nerve fiber, the greater the conducting velocity.
Receptor Potentials
- Receptor potentials are local graded changes in membrane potential produced in response to a stimulus.
- The amplitude of the receptor potential increases with increased stimulus, but then decreases as the stimulus continues.
- Receptor potentials can be phasic or tonic, depending on the type of stimulus and receptor.
Test your knowledge of the different types of sensory receptors in the nervous system, including olfactory receptors, taste receptors, and receptors for touch, pressure, temperature, and pain. Learn about the structure and function of these receptors and how they help us perceive the world around us.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
