Proprioception Flashcards
Define proprioception
The ability to sense stimuli arising within the body regarding position, motion and equilibrium
Name the 5 components of a reflex arc
- Receptor
- Sensory neurone
- Integration centre
- Motor neurone
- Effector
What does the sensory neurone do
It transmits afferent information to the CNS
What is the integration centre
One or more synapses in the central nervous system
What does the motor neurone do
It conducts efferent impulses to the effector organ
Give an example of an effector
Muscle fibre
Gland
What is sensory transduction
The conversion of environmental signals to electrochemical impulses
Give some examples of sensory modalities
- Senses (Touch, hearing, seeing, smelling, tasting)
- Pain, balance, body positioning movement
- Internal subconscious signals
What are sensory receptors
They are structures that are specialised to respond to changes in their environment
What are changes in the environment called
Stimulus
What can sensory receptors be
Free endings of sensory neurones or specialised sensory structures
What does activation of sensory receptors lead to?
Results in local depolarisations that in turn trigger action potentials in the afferent fibres communicating with the CNS
What does sensory transaction require
- Detection
- Amplification
- Local receptor potential
What does local receptor potential cause
A graded electronic repose that leads to an action potential
What does the magnitude of the receptor potential depend on
Strength of the stimulus
When does an action potential occur
When the receptor potential is large enough and the neurone reaches the potential energy
What can sensory receptors be classified by
- Location
2. Function
List some ways sensory receptors can be classified by location
- Exteroceptors
- Interoceptors
- Proprioceptors
What are Exteroceptors sensitive to
Stimulus outside of the body eg touch pressure. temperature pain
What do Interoceptors response to
Stimuli from the body such as internal viscera, blood vessels
What do Proprioceptors do
They advise the brain of own movements or position
Where are Proprioceptors located
In the:
- Skeletal muscles
- Tendons
- Joint capsules
- Ligaments
- Connective tissue
List some ways sensory receptors can be classified by function
- Mechanoreceptors
- Thermoreceptors
- Photoreceptors
- Chemoreceptors
- Nociceptors
What are mechanoreceptors sensitive to
Touch pressure
Vibration
Stretch
What are Thermoreceptors sensitive to
Heat
Cold
Temperature change
What are Photoreceptors sensitive to
Light energy
What are chemoreceptors sensitive to
Chemical stimuli eg taste, smell, blood content
What are Nociceptors sensitive to
Pain (usually chemical)
Name a subgroup of mechanoreceptors
Proprioceptors
What does fast adapting refer to when describing receptors
Receptors that response to declines rapidly with continuous stimulation eg changes in temperature
What does slow adapting refer to when describing receptors
Receptors that contuiout to repose as long as the stimulus is there
What is another term for fast adapting receptors
Phasic receptors
Give examples of phasic receptors (fast adapting)
Thermoreceptors
What is another term for slow adapting receptors
Tonic receptors
Give examples of tonic receptors (slow adapting)
Nociceptors
Mechanoreceptors
What happens to mechanoreceptors when they detect a stimuli
Stimulus causes membranes to distort at the receptive ending
This results in mechanosenstive ion channels opening
What are some mechanoreceptors specialised to do
- Some are specialised for fine sensitive perception
2. Some for crude detection
Describe free sensory endings
Unencapsulated free nerve endings of sensory neurones
Distal endings have small knoblike swellings
How can free sensory endings be classified based on location
Exteroceptors,
interoceptors
proprioceptors
How can free sensory endings be classified based on pain
nociceptors
chemoreceptors,
thermoreceptors,
mechanoreceptors
Where are free sensory endings found
- Most tissues
Most dense cognitive tissues
Epithelia
What are root hair plexuses
Modiefed unencapsulated free nerve ending that entwine basket like in hair follicles
How can root hair plexuses be classified based on location
Exteroceptors
How can root hair plexuses be classified based on stimulus
mECHANORECEPTORS
Where can root hair plexuses be found
In and surrounding hair follicles
Describe merkel disks
They are unencapsualted free nerve endings associated with disk shaped epidermal cells
They attach to the deeper layers of skin epidermis
What is another name for Merkel disks
Tactile disks
How can Merkel disks be classified based on location
exteroceptors
How can Merkel disks be classified based on stimulus
Mechanoreceptors
Where can Merkel disks be found
At base of the epidermis of skin
Sweat ridges of fingertips
What is the function of merkel disks
Information regarding pressure and texture of touch
Describe Pacinian Corpuscles
Single nerve ending surrounded by up to 60 layers of flattened Schwann cells enclosed by connective tissue capsule
How can Pacinian Corpuscles be classified based on location
exteroceptors,
interoceptors
some proprioceptors
How can Pacinian Corpuscles be classified based on stimulus
Mechanoreceptors
Where can Pacinian Corpuscles be found
Dermis and subcutaneous tissue of the skin Masentery Tendors Ligaments Joint capsules Most abundant on fingers Soles of feet External genitalia Nipples
What is the function of the Pacinian Corpuscles
Sensitivity to pain, pressure and stretch
Describe Ruffini’s Corpuscles
Spray of branched nerve endings enclosed by a capsule
How can Ruffini’s Corpuscles be classified based on location
exteroceptors
proprioceptors
How can Ruffini’s Corpuscles be classified based on stimulus
Mechanoreceptors
Where can Ruffini’s Corpuscles be found
Deep in dermis
Hypodermis
Joint capsule
What is the function of Ruffini’s Corpuscles
Sensitive to stretch
Contributes to kinesthetic sense of/control of finger position and movement
Describe Meissner’s Corpuscles
Small receptors in which few spiralling nerve endings are surrounded by Schwann cells and then by a thin egg shaped capsule of connective tissue anchoring to the epidermis
How can Meissner’s Corpuscles be classified based on location
exteroceptors
How can Meissner’s Corpuscles be classified based on stimulus
Mechanoreceptors
Where can Meissner’s Corpuscles
Dermal papillae of hairless skin particularly lips, nipples, external genitalia, fingertips, eyelids.
What is the function of Meissner’s Corpuscles
Sensitivity to light touch and changes in texture
What are Meissner’s Corpuscles called
Tactile Corpuscles
Describe Krause’s end bulbs
Dendrite like endings are surrounded by Schwann cells and then by a thin egg shaped capsule of connective tissue
How can Krause’s end bulbs be classified based on location
Exteroceptors
How can Krause’s end bulbs be classified based on stimulus
Mechanoreceptors
Where can Krause’s end bulbs be found
Connective tissue of mucosae (mouth, conjunctiva of eye) and of hairless skin near body openings (lips), genitalia
What is the function of Krause’s end bulb
Detect low frequency vibration and changes in texture
What does Proprioception mean
Sense of self
sense of where our limbs are in space
What do Proprioceptors in the limbs do
They are sensors that provide information about joint angle, muscle length and tension
Give examples of different types of Proprioceptors
- Muscle spindles
- Golgi tendon organs
- Joint receipts
What are phasic receptors
Fast adapting receptors
What are tonic receptors
Slow adapting receptors
Describe muscle spindles
They are bundles of modified skeletal muscle fibres enclosed in connective tissue capsule
What do intrafusal fibres detect
Detects stretch and initiate reflex
How can muscle spindles be classified based on location
proprioceptors
How can muscle spindles be classified based on stimulus
mechanoreceptors
Where can muscle spindles be found
Skeletal muscles
Name the major proprioceptors
Muscle spindles
What do muscle spindles consist of
Stretch receptors inside a skeletal muscle sensitive to the length of the muscle
What do muscle spindles contain
Contains specialised cells called intrafusal fibres that have nerve endings wrapped around their central regions
How are muscle spindles activated
Stretch of the muscle stretches this central region and activates the muscle spindle Ia afferents.
Where do muscle spindles send impulses to
Spinal cords
Describe Golgi tendon organs
They are small bundles of tenon fibres enclosed in a layered capsule with endings coiling between and around the fibres
Where can golgi tendon organs be found
Tendons
Name the second major proprioceptor in muscles
Golgi tendon organs
What are golgi tendon organs activated by
Tension
Where does all All proprioceptive information come from
from the periphery along sensory afferent nerves via dorsal root ganglion neurones.
Where does information from the proprioceptors travel to
The spinal cord
Describe the pathway information from the cranial regions come from
Information from cranial regions (face, oral cavity, etc) enters CNS via trigeminal (V cranial) nerves and trigeminal ganglion
What is all sensory information from the limbs and trunk conveyed by
DRG neurones
What is Somatosensory information from the cranial structures transmitted by
trigeminal sensory neurones, which are functionally and morphologically homologous to the DRG neurones.
What is the function of DRG neurones
- stimulus transduction
2. transmission of encoded stimulus info to the CNS
Name the 3 divisions of the trigeminal nerve
V1 Ophthalmic
V2 Maxillary
V3 Mandibular
What does the ophthalmic nerve do
carries sensory information from the scalp and forehead, the upper eyelid, the conjunctiva and cornea of the eye, the nose, the nasal mucosa, the frontal sinuses and parts of the meninges
What does the maxillary nerve do
carries sensory information from the lower eyelid and cheek, the nares and upper lip, the upper teeth and gums, the nasal mucosa, the palate and roof of the pharynx, the maxillary, ethmoid and sphenoid sinuses and parts of the meninges.
What does the mandibular nerve do
carries sensory information from the lower lip, the lower teeth and gums, the chin and jaw, parts of the external ear and parts of the meninges.