Lecture 7: Receptor Physiology Flashcards
________ is for information from the external world (hearing, vision , touch)
Exteroreceptor
______ is for information from the musculoskeletal system ( deep sensation from the muscles, tendons, joints)
Propeioceptors
_____ is for information from the internal organs
Interoreceptors
Cranial nerves attach to _____
Spinal nerves attach to _____
Brain
Spinal cord
_____ sensory : touch, pain, pressure, vibration, temp, and proprioception in skin, body wall, and limbs. Hearing, equilibrium, vision, smell
Somatic
Somatic sensory and visceral sensory belong to ______ division
Sensory (afferent)
_____ sensory: stretch, pain, temp, chemical changes, and irritation in viscera: nausea/hunger. Taste
Visceral
Somatic motor and visceral motor belong to ____ division
Motor (efferent )
____ motor: motor innervation of all skeletal muscles
Somatic
______ motor: motor innervation of smooth muscle, cardiac muscle and glands: equivalent to autonomic nervous system. Divides into _____ division and ___ division
Visceral
Parasympathetic
Sympathetic
__________is the link between the periphery and the CNS
Peripheral nervous system
________ division : information from receptors about internal and external environment toward CNS-> sensory - somatosensory, visceral sensory
Afferent
_____ division: response that controls the effectors (skeletal muscles, tissues, and other organs) -> motor- somatic motor visceral motor
Efferent
Peripheral nervous system consists of _____ that carry information between the CNS and other parts of the body
Nerve fibres
Sensory information can be integrated in the _______ or can travel directly to higher levels in the brainstem, and thalamus
Spinal cord
_______ sensory neuron : afferent neuron with its peripheral receptor that first detects stimulus
1st order
______ sensory neuron:
Located in the thalamus
3rd order
____ sensory neuron:
Either in spinal cord or medulla, synapses with 3rd order neuron
2nd order
Sensory information
______ - pain, temperature, tactile, proprioceptive ( from skin, muscles, joints, inner ear)
Somatic
Sensory information :
_____ - pain, temperature, stretch, chemical, osmotic
Visceral
Sensory information
________ - vision, hearing, balance , taste and smell
Special senses
________ at peripheral endings of afferent neurons or receptor cells detect stimuli (change detected by body)
Sensory receptor
________ conversion of different forms of energy into electrical signals (action potentials)
Sensory transduction
_______ - different types of sensation (sound, light , taste, touch , pain )
Modality
_______ : responsive to visible wavelengths of light
Photoreceptors
_____ sensitive to mechanical energy
Mechanoreceptors
_____: sensitive to heat and cold
Thermoreceptors
______: sensitive to pain
Nociceptors
_________ : sensitive to specific chemicals
Include receptors for smell, taste and receptors that detect 02 and c02 concentration in blood and chemical content of digestive tract
Chemoreceptors
_______: detect changes in osmotic pressure
Osmoreceptors
_______ each type of receptor is specialized to respond to one type of stimulus. Requires the least amount of energy to activate that particular receptor- the form of energy which the receptor is most responsive
Adequate stimulus
__________ - the sensation characteristic of each sensory neuron is produced by its adequate stimulus
Law of specific nerve energies
Stimulus alters receptor’s permeability, usually by causing nonselective opening of all small _______
opening of all small ion channels
•This change in membrane permeability can lead to the influx of _____ ions -> depolarizes the receptor membrane (usually)
Ion channels
Sodium
•This local depolarization (graded potential) is known as a __________in the case of a separate receptor, or a generator potential in the case of the specialized ending of a nerve fiber
•Receptor or generator potential - graded potential whose amplitude and duration can vary
- The stronger the stimulus, the greater the ________change and the larger the potential
• Receptor potentials have no __________-> summation is possible with rapidly successive stimuli
Receptor potential
Permeability
Refractory period
_____ receptors : do not adapt at all or adapt slowly
Muscle stretch receptors, joint proprioceptors
Tonic
_____ receptors: rapidly adapting receptors
Tactile receptors in skin
Phasic
A particular modality detected by a specialized receptor is sent over a specific afferent and ascending pathway to excite a defined area in the _________
Somatosensory cortex
______: 1:1 association of receptor with a sensation -> labeled line coding
Somatosensory
Most sensory pathways project to the_____. This modifies and relays information to cortical centres
Thalamus
_______: the region f skin surface that the somatosensory neuron responds to
Receptive field
The receptive field is a circumscribed area of the skin surrounding the point of stimulation. The ______ the receptive field for a sense on the skin surface, the ______ the acuity.
Smaller
Greater
________: The smaller the receptive field is in a region, the greater its acuity or discriminative ability
Acuity
_______: influences acuity
Lateral inhibition
______enhances localization and contrast of stimuli
Lateral Inhibition
A ___________ represents a map of brain areas dedicated to sensory processing for different anatomical divisions of the body. The primary sensory cortex is located in the __________, and handles signals coming from the thalamus.
sensory homunculus
postcentral gyrus
The rate of action potentials is proportional to _______intensity
Stimulus
______ - a reduction in receptor potential despite sustained stimulation of the same magnitude
•Here, it is a reduction in the number of action potentials in response to the continuous presence of a stimulus
•Helps prevent sensory overload
Adaptation
________: Stimulus above threshold gives rise to APs in a sensory neuron that projects to the CNS
• Stimulus intensity and duration are coded in the pattern of APs reaching the _____
Receptor potential
CNS
Stimulus location and modality are coded according to which receptors are activated (RECEPTIVE FIELD ) and fine-tuned by _______
• Each sensory pathway projects to a specific region of the ________ dedicated to a particular receptive field.
• For somatosensory system, it follows “________”
Lateral inhibition
Cerebral cortex
Labelled lines
