Topic 2: Sensory Information (Bridge) Flashcards
The PNS carries ______ information to CNS
Sensory (afferent)
The sense of the relative position of neighbouring parts of the body without the use of vision is _____
Proprioception
Interoception is the perception of _____
Bodily sensations including pain, temperature, itch, sensual touch, visceral sensations, hunger, thirst, “air hunger” and emotional awareness
Internal and external environment reaches the CNS in the form of ________
Action potentials (APs) aka nerve impulses
T/F: Even if our sensory receptors are normal, if our perception is abnormal it will change the information we sense and the interference we make
True
______ is a decreased CNS response to a repeated stimulus
Habituation
______ is an increased response to a repeated stimulus
Sensitization
T/F: All unipolar neurons are sensory (afferent) neurons
True
The terms ______ or ______ signifies that a neuron is in the process of sending a nerve impulse
Firing or Depolarizing
What is adaption?
Decrease in sensory receptor (PNS) sensitivity during a long-lasting stimulus
Receptors which continue to respond throughout the duration of a prolonged stimulus are termed _____
Slow adapting
Ex: nociceptors
Receptors that respond best to change are called _____
Fast adapting
Ex: Olfactory receptors
What is absolute threshold ?
Smallest amount you can just sense ‘something about half of the time’
What is difference threshold?
Smallest amount of change needed in a stimulus before we notice the change
_______ states that the change needed to notice a difference between two stimuli is proportional to the original intensity of the stimulus
Weber’s Law
The ability to accurately locate the site of stimulation and to detect that neighbouring stimuli are actually separate
Spatial discrimination
What is the two-point threshold?
The minimal distance in which two separate stimuli can be distinguished as separate
An area of skin that is a combination of the receptive field of the sensory axons originating from a single nerve
Dermatome
C5
Lateral shoulder and arm
C7
Middle finger
C6
Thumb, index finger (radial border of hand)
C8
4th/5th finger (ulnar border of hand)
T1
Medial elbow
T2-T12
Intercostal nn. form segmental strips on thorax
T10
Across umbilicus
T12
Goes across upper edge of the pubic bone
What are the different types of Receptor Classification
- Classification by Location: Cutaneous Receptors
- Classification by Morphology
- Classification by Adequate Stimulus
Which cutaneous receptors are found in the upper most part of the dermis, especially superficial layers of glabrous skin(fingertips, lips) and what do they detect?
Meissner corpuscles & Merkel cells. They detect discriminative touch
Which cutaneous receptors are also found in glabrous skin?
Ruffini or bulbous corpuscle. They are sensitive to skin stretch, monitor slippage of objects along the surface of the skin, allowing grip on objects
Which cutaneous receptors are found deeper in the skin & subcutaneous tissue?
Pacinian corpuscle. They detect ‘deep touch’ (pressure)
Which cutaneous receptors are multi-layered capsules w/ many branched nerve endings?
Build of Krause. They help us feel extreme cold
What are the Two major types of Nociceptors
A-Delta
C aka C-PMN (Polymodal)
Which of the Two major receptors are myelinated?
A-Delta
The stimulus for C-PMN are
Thermal
Mechanical pressure
Chemical
A-Delta Distributes where
Superficial skin, infolding of the alimentary canal
Associated neuron speed for A-Delta is ____
Carries fast, ‘first pain’
Receptive fields for C-PMN are ___
Large, sensations not as clearly localized
The perceptive correlation for A-Delta is____
Sharp, stinging, cutting, stabbing
What is the pain behaviour for C-PMN and A-Delta
C-PMN: immobilization
A-delta: Withdrawal response
The perceptive correlation for C-PMN is _____
aching, burning, dull, throbbing, itching
What do muscle spindles detect?
1) rate of change in muscle length (stretch)
2) static length of the muscles
T/F: Muscles spindles are abundant in the small muscles of the hand and foot
True
Exceptions include the tongue and ocular muscles in which they are scarce
What is the unipolar neuron coming from a mm. spindle referred to as ____
1a fibre
Muscles spindles consist of _______ fibres
Intrafusal muscle fibres
What do muscle spindles do?
They send information about muscle stretch to the CNS
What is the most abundant type of LMN?
Alpha motor neurons
Alpha motor neurons innervate ______ fibers
Extrafusal muscle fibers (aka skeletal muscle fibers) outside of the spindle
