Senses and perception Flashcards
What are the two branches of a sensory neuron?
Periphery branch
CNS branch
What is a nociceptor?
Pain receptor
What does the distribution of receptor endings define?
A neurons receptive field
Where will you find small and large receptive fields?
Small in the periphery and large in the trunk
What is the normal typical resting potential?
-70mV
What are ionotropic receptors?
Fast kinetics
Ion channels that open in response to the binding of a neurotransmitters
What is found on the extracellular side of a ionotropic chemoreceptors?
Ligand binding sites
How does a G protein coupled chemoreceptor work?
Much slower rate of action
Ligand binding site, which trigger G protein to open Ion channel
What does the intensity of the stimulus code for?
AP frequency
Number of neurons activated
What is the duration of the stimulus coded by?
Real time duration of AP firing
What is a slowly adapting response?
Large no of APS at the start of stimulus and less at the end
What is a rapidly adapting response?
Rapid APs at the onset of the stimulus and then becomes silent
Where is the primary sensory cortex?
The middle of brain behind primary motor cortex
Why is the sensory homunculus distorted body map?
The larger regions of the body have larger receptor fields so don’t require as much of the cortex, the smaller areas such as fingertips have numerous receptor fields so require a larger cortical representation
What type of nerve endings do nociceptors have?
Free nerve endings
What are some different examples of mechanoreceptor endings in skin?
Merkel Disk
Hair follicle receptor
Ruffini ending
What does a peripheral nerve contain?
Axons from two functionally distinct types of nerve cells
What can sensory and motor neurons be known as?
Sensory - Afferent
Motor - Efferent
What are large bundles of axons called?
Fascicle
What strong connective tissue surrounds groups of axons?
Epineurium
What surround an individual fascicle?
Perineurium
Why are blood vessels found in peripheral nerves?
Supply nutrients for AP’s, requires O2 and Glucose and also removed bi-products
What are the 2 types of axons in a peripheral nerve?
Myelinated
Unmyelinated
What type of receptors usually have A ALPHA type of myelinated axon?
Proprioceptors of skeletal muscle
High speed AP
What type of receptors are associated with A BETA myelinated axons?
Mechanoreceptors of skin
What type of receptors are associated with A DELTA myelinated axons?
Pain and temperature
What type of receptors are associated with C class myelinated axons?
Temperature, pain and itch
What are the three sections of grey matter?
Dorsal horn
Intermediate horn
Ventral horn
Where are motor neurons cell bodies found?
Inside ventral horn
Dorsal roots enter Ventral roots exit!!!!
What is a dermatome map?
Sensory neurons projecting to different segments of the spinal chord
What is a myotome map?
Map to show which segment of the spine innervates each motor neuron
What components of the Trigeminal nerve V are sensory?
Ophthalmic branch
Maxillary nerve
What branch of the trigeminal nerve has both sensory and motor functions?
Mandibular
What is mechanoreception?
Reception of touch
What is nociception?
Reception of pain
What are the three main neurons in the sensory pathway?
Primary sensory neuron
Secondary sensory neuron
Tertiary sensory neuron
Where would you find the primary sensory neuron?
The periphery and terminals in the CNS
Where would you find the secondary sensory neurons?
Spinal chord or brain stem
The secondary sensory neuron relays information to where?
The other side of the body
DRAW THE DORSAL COLUMN-MEDIAL LEMNISCAL PATHWAY
What is the somatic mechanosensation around the face conducted by??
Trigeminal nerve
DRAW POSTERIOR (DORSAL) TRIGEMINOTHALAMIC PATHWAY
DRAW SPINOTHALAMIC PATHWAY (pain)
DRAW ANTERIOR (ventral) TRIGEMINOTHALAMIC PATHWAY
What is sensation?
The process of sensing our environment by activation of sensory receptors
What is perception
The interpretation of sensory input
What is stereognosis?
The mental perception of objects referenced by touch stimuli
What is proprioception?
The ability to sense of self movement and body position
