Exam 3 Flashcards
Transduction
taking a sensory stimulus and converting it into an action potential, made possible through sensory receptors of different kinds
What signal does the nervous system understand
an action potential
Signal transduction systems
some first messenger outside of the cell changes or leads to something in the cell such as some protein kinase activity
Mechanoreceptor
receptor that responds to a mechanical stimulus
Chemoreceptor
receptors that respond to a chemical stimulus
Noiceptors
change chemical signals in the environment that indicate there’s damage to other tissues
Prostaglandin and potassium
are primary chemical signals nocieptors pick up on, potassium is in high concentration inside the cell so when the cell is lysed open the nocieptors will detect the potassium
Photoreceptors
receptors that respond to a change in activity of rods and cones
Sensory receptive field
an area of internal/external environment that a sensory receptor responds to, there’s an overlap of receptive fields of sensory receptors and the field is variable in size
Sensory receptors
produce receptor potentials which are graded potentials that may or may not lead to an action potential
Sensory receptors specialized endings
they will change the activity of the cell leading to change in activity of the CNS, most nervous system cells are like this as are most nociceptors
Specialized endings
pick up a stimulus or stimulus energy and act on an individual cell which will then signal another cell
Sensory neuron cell body in the CNS
will send out a process to the periphery that will receive to some part of the skin, free nerve endings radiate in the skin and will pick up on pain signals
Sensory neuron cell body in the periphery
will change the activity of another neuron which will then signal to the CNS, as seen with the eyes
Receptor potential
graded potentials, that may or may not lead to an action potential if the graded potentials summate and reach threshold
When will graded potentials and receptor potentials be recorded in a sensory neuron
before myelination starts, myelination will start at the axon hillic and everything before then is a graded potential (EPSP/IPSP), after receptor potentials the action potentials will be recorded in the nodes of ranvier starting at the first node of ranvier
Stimulus intensity and receptor potential and action potentials
as the stimulus intensity increases the receptor potential amplitude will increase as graded potential amplitude is dependent on the amount of stimulus, an increase to stimulus intensity the frequency of action potentials increase
Pressure and action potentials
the brain can distinguish between the amount of pressure on the skin based on the frequency of action potentials
Principles of sensory system organization
specific sensory receptor types are sensitive to certain modalities and submodalities, specific sensory pathways code for a particular modality or submodality, specific ascending pathways are crossed so that sensory information is generally processed contralaterally, the thalamus is the brain’s sensory relay station, specific ascending pathways are subject to descending control
Exceptions to contralateral control
vision and gustatory
Thalamus
all sensory information except the sense of smell will go to the thalamus first and after it will go to specific cortical areas
Ascending vs Descending
ascending is sensory and descending is motor as seen in the cross extensor reflex
Cross extensor reflex
if you were to step on something you have to lift your foot up and the quadriceps of the other leg has to tense up
Visible light spectrum
400nm to 750nm, as wavelength increases energy decreases, as approach blue the energy increases