Sensory Receptors (S2 L1) Flashcards
What are sensory receptors?
Specialised cells that provide the CNS with information (stimuli) about conditions inside or outside of the body.
What does the activation of a sensory receptor by an adequate stimulus result in?
Depolarization or graded potentials.
What does depolarization or graded potentials trigger?
This triggers nerve impulses along the afferent fibres (coursing to the CNS).
Nerve impulses travel along the ________ fibres coursing to the ______.
Afferent, CNS.
What is arriving information called?
Sensation.
What is the conscious awareness of a sensation called?
Perception.
Describe the distribution and structure of special senses.
Special senses are localised and are complex in structure.
What type of sensory receptors are widely distributed and simple in structure?
General Sensor Receptors.
The information from special senses is distributed to _____ areas of the ______ _______ and to centres throughout the _____ ______.
Specific, Cerebral, Cortex, Brain Stem.
Name the 4 special senses.
- Hearing and Balance
- Olfaction (smell)
- Gustation (taste)
- Sight (vision)
For hearing and balance, the sensory organ is the ____ and the special sensory receptors are the _____ and the _______.
Ear, Cochlea, Labyrinth.
What body part do we use for Olfaction? Name the receptors found here.
The Nose, Olfactory receptors.
What is the scientific name for taste?
Gustation.
The ______ receptors in the _____ are responsible for gustation.
Gustatory, tongue.
What are the special receptors found in the eye that allow vision?
Photoreceptors (rods and cones)
Some of the information that General Sensor Receptors send to the _____, reaches the _____ ______ cortex and our ______ ________.
CNS, primary sensory, conscious awareness.
Name the 4 types of General Sensor Receptors.
- Nociceptors
- Thermoreceptors
- Mechanoreceptors
- Chemoreceptors
Nociceptors respond to _____.
Pain.
What type of general sensor receptor responds to temperature?
Thermoreceptors.
What do Mechanoreceptors respond to?
Physical Distortion.
What type of receptor responds to changes in chemical concentration?
Chemoreceptors.
Name the 3 Broad Functional Categories of the General Senses.
- Exteroceptors
- Proprioceptors
- Interoceptors.
______ provide information about external environment (touch, pressure, vibration, pain, temperature, special sense receptors).
Exteroceptors.
What category of the general senses provides information about body position and movement by monitoring the degree of stretch?
Proprioceptors.
What do Interoceptors provide information about? Give a few examples.
They provide information about internal systems. eg. chemical changes, tissue stretch and temperature changes.
What are sensory receptors found in the dermis/epidermis known as?
Cutaneous Sensory Receptors.
What types of receptors does cutaneous sensory receptors include?
Mechanoreceptors, Nociceptors and Thermoreceptors.
What receptor detects light touch and rapidly adapt low threshold afferents?
Hair Follicles
Hair follicles have the perceptual function of what?
skin movement.
What mechanoreceptor lies in the dermis and responds to the stretch of skin?
Ruffini Corpuscles.
Ruffini corpuscles are SA Cutaneous mechanoreceptors, and contribute to the perception of object _____.
Motion.
Mechano-nociceptor and Polymodal nociceptor detect ________ or _____ to the _____.
Pain, Injury, skin.
There atre 3 types of Cutaneous _____.
Afferents.
Name the 3 types of Cutaneous Afferents.
- Type II sensory fiber (group Aβ)
- Type III sensory fiber (group Aδ fiber)
- Type IV sensory fiber (Group C)
The thickest cutaneous afferent is Type __.
Type II (group Aβ)
Type II (group Aβ) have _________ rapidly and slowly adapting ______________.
Various, Mechanoreceptors.
Type III/group Aδ fibers are _____ than Type II/group Aβ fibers. Name the types of information that runs along this afferent.
Thinner,
pain, temperature etc.
Type C afferents are the thinnest and are _________.
Unmyelinated.
What information does Type C carry?
Pain.
Name the 2 types of mechanoreceptors for proprioception.
Muscle Spindles
Golgi Tendons
Muscle Spindles can be thought of as what detectors?
Length detectors.
Muscle spindles contain Group ____ for velocity and direction and Group ____ for sustained static position.
IA
II
Golgi Tendons can be thought of as a ______ detector.
Force.
Golgi tendons detect _____ whereas muscle spindles detect ____.
Force.
Length
Golgi Tendon contain Group ____ afferent neurons, branched in ____ fibres to form _____.
Ib, Collagen, Tendons.
Alpha Motor neurons and Gamma Motor neurons are ______ ________.
Somatic Efferents.
Alpha motor neurons are _____ diameter Type A large anterior horn cells/motor neurones that innervate _____ __________.
Large, Skeletal muscle.
Gamma Motor neurons are ____ diameter Type A axons innervating _______ _______ fibres.
Small, Intrafusal Muscle.
How are peripheral nerves classified?
According to conduction velocity/fibre diameter.
The diameter of afferent fibres innervating ,muscle have different _____ from those innervating the _____.
Distribution, skin.
_____ afferents are classified as follows:
- Group I (Αα) = ______ myelinated fibres (proprioceptors)
- Group II (Aβ) = small ______ fibres (proprioceptors)
- Group III (Aδ) = ______ myelinated fibres (proprioceptors/____)
- Group IV (C) = _______ (pain)
Muscle Large Myelinated Smallest, pain Unmyelinated
Afferents lead to the ______.
CNS.
Name order of the Somatic Sensory Pathway (from the spinal cord).
Spinal Cord > Medulla > Mid-brain > Thalamus.
Where are sensations perceived?
In the primary sensory cortex.
Sensory pathways synapse in the ______.
Thalamus.
Pain, temperature and coarse touch information go to the _____ ______.
Spinal cord.
Fine touch, vibration and proprioception pathways cross the midline in the _______.
Medulla.
The CNS receives input from a large number of sensory receptors, what is this known as?
Sensory Transduction.
The Peripheral Nervous system is split into ______ and ______.
Motor, sensory.
Information from the PNS goes to the _____ _____.
Spinal Cord.
Special senses (Sight, taste, smell and hearing) information goes straight to the ______.
Brain.
What is the “language” of the CNS?
Electric Signals.
What must each receptor cell convert its sensory input/stimulus, into?
It must convert the stimulus into an electric signal.
Structures with sensory receptors have selectivity. What is meant by this?
They only respond to a particular stimulus and this stimulus must be adequate.
The steps to convert a stimulus into an electrical signal:
- External ______.
- _____
- _______
- ______
- Then a _______ (electrical signal).
Signal Receptor Transducer Amplifier Response
A stimulus can cause a _____ change in membrane.
Structural.
The structural change in membrane causes conductance change, causing a receptor ___, which then causes a receptor ______. This then passes from the 1st order neuron to the ____ _____ neuron.
Current, Potential.
2nd Order.
An ____ stimulus will open ____ at the receptor.
Adequate, channels.
The opening of channels at the receptor results in an inward flux of ______ which causes _______.
Sodium, depolarization.
A receptor potential is a type of ____ _______.
Graded Potential.
The stronger the stimulus the greater the ____ potential.
Graded.
Graded Potentials have no ____ period, so what does this mean?
Refractory, This means that sustained contraction is possible.
What is the order of events from receiving a stimulus to perceiving it? (4 processes)
- Reception
- Transduction
- Transmission
- Perception
Sensory neurones transform a physical ____ into and ____ _______.
Stimulus, electrical activity.
Define Adaptation?
The different responses of different receptors to a similar stimuli.
_____ receptors are always active.
Tonic
Tonic receptors generate ____ ______.
Action potentials.
Pain receptors, Joint capsules and ,muscle spindles are examples of ____ receptors.
Tonic.
What type of receptor is normally inactive?
Phasic receptor.
When do Phasic Receptors become active for a short time (think phases)?
When there is a change in the conditions are monitoring.
Tonic receptors are ____ adapting receptors and respond for the _____ of the stimulus (always active) whereas Phasic receptors ______ adapt to a constant stimulus and turn ___.
Slowly, Duration, Rapidly, Off.
Graded Potentials can vary in ______ whereas the action potentials are the ____, as long as its triggered (all or none principle).
Magnitude, Same.
Graded Potentials have no ____ and no _____ period.
Threshold, Refractory.
Graded potentials can be _____ or _______, whereas action potentials can only be _______.
Depolarization, Hyperpolarization, Depolarization.
What are graded potentials initiated by?
Environmental Stimulation of Receptors, by neurotransmitter release at synapse between neurones.
Action potential duration is ______ whereas Graded potential can ____.
Constant, Vary.
______ potential is initiated by membrane depolarization.
Action.
What potentials are dominated by receptor gated channels?
Graded Potentials
_____ potentials are dominated by sensitive/dependent ion channels.
Action.
What stage does the Involuntary Motor Pathway not have?
Perception stage (as we do the action unconsciously, without thinking about it).
Fill in the blanks:
- Arriving _______
- ____ Potential Generation
- Propa_____
- _____ processing
- Voluntary or Immediate Involuntary _____
Stimulus Action Propagation CNS Response
What does local anaesthetic block and how?
It blocks action potential propagation by acting on sodium channels.
Conduction block occurs based on axon ______. Firstly it blocks small ____ axons (pain), the ________ axons and finally ____ myelinated axons (motor and sensory).
Diameter.
Myelinated, non-myelinated, large.
The order of block of a local anesthetic is:
- Most Importantly _____, then
- Temperature
- Touch
- Proprioception and ______.
Pain
Motor.
The effect of pressure block or electrical stimulation happens in _____ order from anaesthetic block. The axons with the ____ diameter are affected.
Reverse, Largest.
