Chapter 16 - Senses Flashcards
– in neuroscience, this term can refer either to a protein that binds and responds to
chemical messenger or it can refer to a cell or structure that converts one kind of energy into
an electrical signal within a cell
Receptors
used for vision
Photoreceptors
used for hearing; touch; proprioception; respond to
stretch or bending of part of a cell
Mechanoreceptors
used for sensing taste (tongue), smell (olfactory), osmolarity
(hypothalamus), O2, CO2 (in hypothalamus and near heart) & H+ (in brainstem)
Chemoreceptors
create a sensation of pain; work by binding chemicals released
during inflammation and tissue injury; technically, they are chemoreceptors
Nociceptors
– pressure (actually a type of mechanoreceptor); found in walls
of major blood vessels and in the lungs to monitor lung expansion and stretch
Baroreceptors
provide information about position, stretch or force of
contraction of muscles, tendons & ligaments in the body. These allow you to
know the position of body parts relative to each other.
Proprioceptors
– the energy that activates the receptor
Stimulus
– process of changing stimulus into a change in membrane potential
Transduction
graded potential generated by sensory receptor; due to
opening/closing of gated channel
Receptor potential
– the type of energy sensed (e.g. light or sound)
Modality
strength of stimulation (e.g. how bright or how loud)
Intensity
– one afferent neuron and all the receptors that send it signals
Sensory unit –
the sensory area covered by one afferent neuron; one sensory unit
defines a receptive field
Receptive field
– precision of the sensation; often related to ability to localize stimulus
(generated by size of receptive fields
Acuity
decreased receptor response with continued stimulation; enhances
ability to detect change & ignore background
Adaptation
something that happens both at the level of the individual receptor and in the CNS.
Adaptation
are receptors that adapt very slowly and generate steady nerve
impulses.
Tonic receptors
c receptors generate a burst of action potentials when first stimulated
(on/off type response); they adapt quickly
Phasic receptors
– respond to chemicals produced by damage to tissues
Nociceptors
Bradykinin (most potent)
Prostaglandins
Serotonin
Histamine
most important and common stimulators of somatic pain.
- Pain can be a sharp, stabbing sensation that occurs very rapidly.
pain conducted via myelinated fibers
Fast
pain can be a longer-lasting, dull, diffuse
sensation. pain conducted unmyelinated fibers
slow
pain comes from
stimulation of skin or proprioceptors
Somatic
pain due to injury to internal organs
visceral
The location that feels pain has somatosensory
fibers coming in along the same dorsal root as visceral sensory fibers from the
affected organ.
Referred Pain
mechanisms for inhibiting nerve signals along pain pathways using enkephalin neurotransmitters (endogenous opiates) as well as pre-synaptic inhibition.
, spinal gating
chemoreceptors for external sensing
Olfaction (smell) & Gustation (taste)
Much of sense of taste
olfaction.
smell
oflaction
taste
Gustation
taste that detects compounds like quinine; GPCR
Bitter –
taste that detects H+ ions; open channels in membrane for H+
Sour/acid
n distinguish between something like 2000-4000
different chemicals; it does this using about 400 different odorant
receptors.
The olfactory system
Structures used for detecting orientation to gravity, as well as movement and
acceleration, key to balance, are
the vestibule & semicircular canals.
detects compression waves of molecules in air
hearing
(X axis =
time