2. Deep/Visceral Pain – diffuse; action potentials
SENSES are propagated more slowly
§ Ability to perceive stimuli
Local anesthesia – injected near a sensory
Sensation/Perception – conscious awareness of stimuli receptor/nerve resulting in reduced pain
received
General anesthesia – loss of consciousness is produced;
affects reticular formation
GENERAL SENSES Gate control theory – inhibits action potentials carried
§ Have receptors distributed over the body
to the brain by the spinothalamic tract
§ Senses for touch, pressure, pain, temp.,
vibration, itch, proprioception Referred Pain
§ Originate in a region of the body that is not the
1. Somatic Senses – provide sensory info about the
source of the pain stimulus
body and the environment
§ Clinically useful in diagnosing the actual cause
2. Visceral Senses – provide info about various of the painful stimulus
internal organs (pain & pressure) § Occurs bcos the sensory neurons (from the
superficial area) to which the pain is referred,
Transduction – a receptor absorbs energy from stimulus and the neurons (from the deeper, visceral area)
where the pain stimulation originates, converge
Sensory Receptors – sensory nerve endings capable of onto the same ascending neurons in the spinal
responding to stimuli by developing action potentials cord; thus the brain can’t distinguish
1. Mechanoreceptors – mechanical stimuli
SPECIAL SENSES
2. Chemoreceptors – chemicals (odor molecules) § Localized to specific parts of the body
§ Smell, taste, sight, hearing, balance
3. Photoreceptors – light
4. Thermoreceptors – temperature changes OLFACTION
§ Sense of smell
5. Nociceptors – sensation of pain § Occurs in response to airborne molecules
6. Free nerve endings – simplest and most Odorants – airborne molecules
common receptors
Ø Cold receptors – decreasing temp.; stop Olfactory neurons – bipolar neurons
responding at below 12OC
Ø Warm receptors – increasing temp.; stop Olfactory epithelium – lines the superior part of the
responding above 47 OC nasal cavity
7. Touch receptors – structurally more complex; Neuronal Pathways for Olfaction
enclosed by capsules § Axons of the olfactory neurons form the
olfactory nerves, which enter the olfactory
8. Merkel disks – light touch and superficial bulb. Olfactory tracts carry action potentials
pressure from the olfactory bulbs to the olfactory cortex
of the brain.
9. Hair follicle receptors – light touch
Olfactory bulb – where olfactory neurons synapse with
10. Meissner corpuscles – fine, discriminative interneurons
touch; localizing tactile sensations
Olfactory tracts – relays action potentials to the brain
11. Ruffini corpuscles – continuous pressure in
skin Olfactory cortex – where each olfactory tract terminates
12. Pacinian corpuscles – deepest receptors; deep Adaptation – feedback + temporary decreased
pressure, vibration, position sensitivity
Pain
§ Unpleasant perceptual and emotional TASTE
experiences Taste buds – detect taste stimuli
1. Superficial Pain – localized; rapidly conducted Papillae – enlargements on the surfaced of the tongue
action potentials
M o r a n o , M . A .
SENSES are propagated more slowly
§ Ability to perceive stimuli
Local anesthesia – injected near a sensory
Sensation/Perception – conscious awareness of stimuli receptor/nerve resulting in reduced pain
received
General anesthesia – loss of consciousness is produced;
affects reticular formation
GENERAL SENSES Gate control theory – inhibits action potentials carried
§ Have receptors distributed over the body
to the brain by the spinothalamic tract
§ Senses for touch, pressure, pain, temp.,
vibration, itch, proprioception Referred Pain
§ Originate in a region of the body that is not the
1. Somatic Senses – provide sensory info about the
source of the pain stimulus
body and the environment
§ Clinically useful in diagnosing the actual cause
2. Visceral Senses – provide info about various of the painful stimulus
internal organs (pain & pressure) § Occurs bcos the sensory neurons (from the
superficial area) to which the pain is referred,
Transduction – a receptor absorbs energy from stimulus and the neurons (from the deeper, visceral area)
where the pain stimulation originates, converge
Sensory Receptors – sensory nerve endings capable of onto the same ascending neurons in the spinal
responding to stimuli by developing action potentials cord; thus the brain can’t distinguish
1. Mechanoreceptors – mechanical stimuli
SPECIAL SENSES
2. Chemoreceptors – chemicals (odor molecules) § Localized to specific parts of the body
§ Smell, taste, sight, hearing, balance
3. Photoreceptors – light
4. Thermoreceptors – temperature changes OLFACTION
§ Sense of smell
5. Nociceptors – sensation of pain § Occurs in response to airborne molecules
6. Free nerve endings – simplest and most Odorants – airborne molecules
common receptors
Ø Cold receptors – decreasing temp.; stop Olfactory neurons – bipolar neurons
responding at below 12OC
Ø Warm receptors – increasing temp.; stop Olfactory epithelium – lines the superior part of the
responding above 47 OC nasal cavity
7. Touch receptors – structurally more complex; Neuronal Pathways for Olfaction
enclosed by capsules § Axons of the olfactory neurons form the
olfactory nerves, which enter the olfactory
8. Merkel disks – light touch and superficial bulb. Olfactory tracts carry action potentials
pressure from the olfactory bulbs to the olfactory cortex
of the brain.
9. Hair follicle receptors – light touch
Olfactory bulb – where olfactory neurons synapse with
10. Meissner corpuscles – fine, discriminative interneurons
touch; localizing tactile sensations
Olfactory tracts – relays action potentials to the brain
11. Ruffini corpuscles – continuous pressure in
skin Olfactory cortex – where each olfactory tract terminates
12. Pacinian corpuscles – deepest receptors; deep Adaptation – feedback + temporary decreased
pressure, vibration, position sensitivity
Pain
§ Unpleasant perceptual and emotional TASTE
experiences Taste buds – detect taste stimuli
1. Superficial Pain – localized; rapidly conducted Papillae – enlargements on the surfaced of the tongue
action potentials
M o r a n o , M . A .
