Chapter 15 SNS Flashcards
Visceral sensory information is primarily distributed to what brain regions?
reflex centers of the brain stem and diencephalon
Transduction
sensory receptors detect arriving stimulus, translate it into an action potential which conducts it to the CNS.
Receptive field
The area monitored by a single receptor cell.
Generator potential
A depolarizing receptor potential in a neural receptor
Labeled line
The link between a peripheral receptor and cortical neuron which consists of axons carrying information about modality (touch, pressure, light and sound)
Sensory coding
the translation of complex sensory information into meaningful patterns.
Tonic receptors
Are always active
Phasic receptors
Usually not active, provide information about intensity and rate of change in stimuli
Adaptation
A reduction in the pressure of a constant stimuli
Includes slow and fast adapting receptors
Fast- adapting receptors
Peripheral adaptation that occurs when the level of receptor activity changes. They respond strongly at first then gradually decrees-phasic (thermoreceptors)
Slow-adapting receptors
Tonic fibers, show little peripheral adaptation they include pain receptors (nociceptors)
General sensory receptors are classified by
the type of stimuli that excites them
Exteroceptors
Provide information about the external environment
Proprioceptors
Report the position and movement of skeletal muscles
Interoceptors
Monitor visceral organs and their functions
Detailed classification of 4 types of receptors by stimulus that excites them
Nociceptors
Thermoreceptors
Mechanoreceptors
Chemoreceptors
Nociceptors
Pain receptors that are especially common in the superficial skin, in joints, in periostea, and round artery walls
Maybe sensitive to:
1. extremes in temperature
2. mechanical damage
3. dissolved chemicals
Type A fibers carry fast pain (pricking)
Type C fibers carry slow pain (burning and aching)
Endorphins and enkephalins are neuromodulators that
inhibit activity along pain sensations
Thernoreceptors
free nerve endings located in the skin and skeletal muscles, in the liver and hypothalamus. Consist of hot and cold but cold are 3-4 times more numerous
Mechanoreceptors
Contain mechanically gated ion channels that close in response to stretching, compression, twisting or other distortions of their membrane. 3 classes are: 1. Tactile 2. Baroreceptors 3. Proprioceptors
Tactile receptors
Provide sensations of touch, pressure and vibration
- free nerve endings: in epidermal cells and the cornea
- root hair plexus: adapt rapidly
- tactile discs/merkle: fine touch
- tactile corpuscle/meissner’s: recieve fine touch pressure and vibration
- lamellated corpuscle/pacinian: deep pressure
- ruffini corpuscle: located in deep dermis and show little adaptation
Baroreceptors
Monitor changes in pressure in an organ and walls of major blood vessels. (carotid sinuses and aortic sinuses) Also in the lungs.
Respond immediately to changes in pressure
Proprioceptors
Monitor the position of joints, tendons and skeletal muscles
3 types are:
1. Muscle spindles: monitor stretch
2. Golgi tendon organs: joint between skeletal muscles and tendons
3. Receptors in joint capsule
Do not adapt and constantly send information to the CNS
Chemoreceptors
Detect small changes in specific chemicals or compounds . Generally only respond to water or lipid soluble compounds.
Monitor pH and CO2 levels in the blood