BIOD27H3 Lecture 11: BGYB30H3 Lecture 11 Notes Sensory 2-Oct 15
BGYB30H3 Lecture 11 Notes
-special senses are conscious and cause voluntary responses (vision, taste, hearing, smell, and
equilibrium)
-somatic senses can either be conscious or unconscious senses causing a response (pain, touch,
proprioception, blood pH, blood pressure, temperature)
-blood pH and pressure are unconscious senses
-sensory systems are activated by physical and sometimes chemical energy
-changes in membrane potential are known as generator/receptor potentials, which are the
same as graded potentials
-integration of a signal in the CNS is through somatosensory cortex (conscious) or spinal cord
(unconscious)
-simple receptor neuron has free nerve endings that come in contact with stimulus (can be
myelinated or unmyelinated)
-complex receptor neuron has connective tissue that covers nerve endings and are always
myelinated
-special senses receptor neuron have a receptor cell that synapses onto the sensory neuron
and are always myelinated
-stimulus hits receptor cell which releases neurotransmitters onto sensory neuron
-chemical stimuli such as taste, smell, oxygen and glucose activate chemoreceptors
-mechanical stimulus such as pressure (baroreceptors), vibration (osmoreceptors) and
acceleration/gravity (proprioception) and sound activate mechanoreceptors
-nocioreceptors respond to pain stimuli
-an adequate stimulus is the form of energy to which that receptor is most responsive to
-CNS integrates sensory info in three ways (olfaction, sensory receptors, and equilibrium)
-olfactory system receives info and relays it through the olfactory bulb to the olfactory cortex
-sensory receptors respond to all stimuli
-equilibrium info is inputed from the inner ear to the cerebellum and not through the
thalamus
-somatic and vision sensory neurons have receptive fields
-receptive fields may overlap to cause variable sensitivities
-convergence of receptive fields decreases sensitivity of primary stimulus
-two or more primary sensory neurons synapse onto a secondary sensory neuron
-in two point discrimination, the outcome is that the receptive field can be detected for one
primary sensory neuron
-ear is sensitive to different frequencies of sound waves
-the timing of stimulation is used to compute the location of a stimulus
-time difference is registered in the auditory cortex of both sides of the brain
-neuron activation is proportional to the stimulus
-in lateral inhibition a secondary neuron that is closest to the stimulus inhibits adjacent
neurons to cause enhanced awareness of location
-lateral inhibition prevents interference caused by adjacent neurons that respond as well
-stimuli modality, location, intensity, and duration are properties of stimuli that the CNS
distinguishes
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Document Summary
Special senses are conscious and cause voluntary responses (vision, taste, hearing, smell, and equilibrium) Somatic senses can either be conscious or unconscious senses causing a response (pain, touch, proprioception, blood ph, blood pressure, temperature) Sensory systems are activated by physical and sometimes chemical energy. Changes in membrane potential are known as generator/receptor potentials, which are the same as graded potentials. Integration of a signal in the cns is through somatosensory cortex (conscious) or spinal cord (unconscious) Simple receptor neuron has free nerve endings that come in contact with stimulus (can be myelinated or unmyelinated) Complex receptor neuron has connective tissue that covers nerve endings and are always myelinated. Special senses receptor neuron have a receptor cell that synapses onto the sensory neuron and are always myelinated. Stimulus hits receptor cell which releases neurotransmitters onto sensory neuron. Chemical stimuli such as taste, smell, oxygen and glucose activate chemoreceptors.