Lesson 7 - Reflexes and Reaction Time Flashcards
Is reaction time voluntary or involuntary?
Voluntary, unlike reflexes
Reaction time is considerably more complex than reflexes as they involve __________
Higher brain functions
Where does the delay for reaction time occur?
At the synapses between the different neurons involved
What are the factors that affect reaction time?
- Age (+/-)
- Arousal (Fastest with intermediate level)
- Distraction (Increases with reaction time)
- Gender (Males generally have faster reaction times than females)
- Practice (More practice decreases reaction time)
- Errors (More errors lead to slower reaction times)
- Fatigue (More fatigue leads to slower reaction times)
- Punishment (-)
- Drugs (Stimulants decrease reaction; depressants increase reaction time)
- Warnings (Reaction time is faster with warning)
It is an instantaneous response to a stimulus.
Reflex
Are reflexes voluntary or involuntary?
Involuntary
A reflex occurs via neural pathways in the nervous system known as __________
Neural Arcs
What are the steps in reflexes?
- Receptors detect a change
- Sensory neurons carry information to the CNS
- The CNS processes the sensory information
- Motor neurons then send the information from the CNS to effector organs (ex: skeletal muscles)
- The effector organ then produces a response appropriate to the stimulus that is perceived (for example pulling your hand away when you actually touch a sharp object)
These are produced via single synapses between sensory axon and motor neurons.
Spinal reflexes
This is the place where neurons connect and communicate with each other.
Synapse
These are nerve cells that communicate information to the CNS and the rest of the body
Neurons
This type of neurons help perceive a stimulus.
Sensory neurons
This type of neurons are for coordinating an action.
Motor neurons
This is a part of the neuron that carries information to and from the spinal cord.
Axon
How many neurons do spinal reflexes use and what are they?
Two neurons: sensory and motor
What are the different types of spinal reflexes?
- Stretch (myotatic) reflex
- Golgi tendon reflex
- Crossed extensor reflex
- Withdrawal reflex
This refers to the contraction of a muscle in response to its passive stretching
Muscle stretch reflexes
Where is the cell body of the sensory axon located to illicit a patellar reflex?
Dorsal root ganglion in the lumbar region of the spinal cord (L2 to L4)
This is also known as the nociceptive flexion reflex
Withdrawal reflex
Withdrawal reflex is important in __________ from harmful stimuli.
Protecting the body
TRUE OR FALSE:
Flexor muscles are stimulated, causing the flexion of your leg towards the stimulus.
FALSE: Away from the stimulus*
TRUE OR FALSE: There is an opposite reaction in the opposite leg to enhance postural support.
TRUE
This is more complex than a regular myotatic reflex.
Pupillary reflex
Pupillary reflex involves:
- Additional cells
- Interneurons
- Four neurons
These are neurons that help in integration of sensory information and motor activity
Interneurons
TRUE OR FALSE: Pupillary reflex results in a shorter delay between stimulus perception.
FALSE: Longer delay*
Pupillary constriction is referred to as __________.
Miosis
Pupillary dilatation is referred to as __________.
Mydriasis
This is characterized by rapid dilation of the ipsilateral pupil (by 1 to 2 mm) with a painful or startling stimulus
Ciliospinal reflex
Contact with the cornea initiates 2 reflexes. What are they?
- Blink (corneal) reflex
- Tear production
This is also known as the oculocephalic reflex or the doll’s eye reflex
Auditocephalogyric reflex
Auditocephalogyric reflex is used to test what?
- Cranial Nerves III, VI, and VIII
- Overall brainstem function
The gag reflex is also known as the __________.
Pharyngeal reflex
It is an involuntary reflex involving bilateral pharyngeal muscle contraction and the elevation of the soft palate.
Gag reflex
The gag reflex test is performed to test which cranial nerves?
CN IX and X
What is the function of the gag reflex?
It attempts to eliminate foreign objects from the oral cavity.
This has receptor organs in the skin rather than in muscle fibers
Skin reflex arcs
FILL IN THE BLANKS:
A __________ plantar reflex is called the __________ and is a sign of a disease of the __________ (corticospinal tract)
Positive; Babinski sign; Pyramidal
