A&P 2.2 Sensation Flashcards
Perception
Conscious awareness of a sensation as interpreted by the CNS
Sensation
Defined
- Subconscious or conscious recognition of stimulus by the CNS
- Starts with a CHANGE IN THE ENVIRONMENT (internal or external)
- A sensory receptor is activated and converts the stimulus to an electrical signal going to the brain
Process of sensation
4 parts
- Stimulus must occur
- Sensory receptors detect internal/external stimuli
- Each sensory neuron conducts a nerve impulse (action potential)
- Action potentials along a SENSORY NEURON stimulate neurons in the CNS
Adaptation
Decrease in strength of a PERCEIVED sensation during prolonged stimulus (hot tub, cold pool, smell)
It is variable
Adaption
Variations
Tactile and smell
Tactile (touch) and smell sensors adapt quickly
Sensitive to change, rather than continuous input
Perception
Variable
Nociceptors and proprioceptors
Nociceptors (pain) and proprioceptors (space)
Continue to trigger nerve impulses as long as stimulus present
Phantom limb
Sensation felt after limb is amputated
Projection
Projection
Perception of stimulus in the brain (illusion creation) at the site of the stimulus
Classification of sensory receptors
General
3 bullets
Each receptor responds to a specific type of stimulus (specialized)
Each neuron conducts an impulse that has a particular function
There are three different classifications and they overlap
classification of sensory receptors by
3
Location
cellular Characteristics
Stimulus
Location
3 types
Exteroceptors
Proprioceptors
Interocepters
Exteroceptors
Skin or cutaneous receptors
On or near the surface, skin and superficial fascia
Usually respond to external stimulus
Example: touch, pressure, pain, vibration, temperature
Proprioceptors
Spacial sensors
Located in skeletal muscles, joint capsules, tendons, ligaments and fascia
Monitors stretch and tension (tugs and pulls), mechanical
Provides us with info about physical orientation and movement
Interocepters
Visceral. Also called enterocepters Located internally (visceral/organs) Respond to internal stimuli (pressure, stretching and chemical changes in the viscera)
Pain felt where
Pain will reside in all three of the locations
Can be felt in skin, muscle and organs
Cellular characteristics
2
Simple
Complex
Cellular characteristics
Simple
2 types
Free nerve endings
Encapsulated nerve endings
Free nerve endings
Dendrites respond directly to stimulus
Example: nocicepters
Encapsulated nerve endings
Dendrites are wrapped in a connective tissue coating
Examples: mechanoreceptors and corpuscles
Cellular characteristics
Complex
Cellular receptors
Entire cells that detect stimuli and initiate sensory impulses
Examples: special senses (sight, smell, hearing, taste, balance)
Classification of sensory receptors
By stimulus
5
Mechanoreceptors Thermoreceptors Nocicepters Photoreceptors Chemoreceptors
Mechanoreceptors
Respond to mechanical deformation of tissue (tugs and pulls)
Thermoreceptors
Respond to changes in temperature
Nocicepters
Respond to pain; actual or near damage to tissue
Photoreceptors
Respond to visible light
Chemoreceptors
Respond to chemical
external: smell, taste,
internal: oxygen or carbon dioxide
Sensory modalities
2 types
General
Special
General senses
Body wide
Simple receptors
Includes the following: touch, pressure, pain, vibration, proprioception, visceral senses
Somatic senses
General
Sensory, include cutaneous and proprioception
Arise from skin, muscles, joints and fascia
Cutaneous sensations
3
Tactile sensations - requires contact ( touch, pressure, vibration)
Thermal sensations - requires temperature change
Pain sensors - nociception
Proprioception
Organs
Special senses
5
Smell Taste Vision Hearing Balance
General senses
2
Somatic senses
Visceral senses
Triceps brachii
A, I, O
A - extends the elbow
O - long head - infraglenoid tubercle;
lateral head - posterior proximal 1/2 humerus lateral to radial/spiral groove;
medial head - posterior distal 1/2 humerus medial to radial/spiral groove
I - olecranon process of ulna for all three heads
Named for three heads, arm
Bony landmarks
Olecranon
Infraglenoid tubercle
Condyles
Radial spiral ridge
Anconeus
A, I, O
A- extend the elbow
O- posterior aspect of the lateral condyle of the humerus
I - olecranon process and posterior, proximal surface of the ulna
