reaction time - lab 2 - physio

nervous system

how our bodies regulate most controlled variables within set limits to maintain homeostasis

• regulate changes in external or internal environment that sets body away from set points

1) sensory

2) integratve

3) motor

stimulus

causes a control variable to deviate from their set point — forms electrical signals through graded/action potentials

electrical excitability

the ability to produce an action potential in RESPONSE to a stimuli

• neurons communicate with other neurons, muscle fibers, gland cells, organs, etc.

sensory

function where receptors detect external or internal stimuli

• info → cranial and spinal nerves of PNS → afferent neurons to brain and spinal cord of CNS

• ex: raindrop on your arm

• ex: increase in blood acidity

integrative

function where CNS processes sensory info by ANALYZING it and make decisions

motor

function where the CNS elicits an appropriate response

• from CNS → cranial and spinal nerves of PNS → effectors via effector neruons

• causes muscle contraction and gland secretion

receptor

structure of beginning of a sensory neuron that receives stimulus

afferent

sensory neuron that relays sensory info FROM receptor INTO brain or spinal cord

• terminate within CNS

CNS

center in the brain or spinal cord where info is relayed across synapses from sensory to motor neuron

efferent

motor neuron where info is transmitted out the brain or spinal cord into effector

effector

smooth muscle cell, cardiac muscle cell, pacemaker system cell, secretory cell (glands), skeletal muscle to provide a reflex or reaction

reflex

involuntary or automatic response to a sensory stimulus

• no forethought or volition

• occurs before the brain has been informed

voluntary response

wilfull and controlled response to a stimulus, modified by learning and experience

ex: track athletes beginner vs pro

reaction time

interval between stimulus delivery and the response to a stimulus

• normally vary from person to person

• more exposed to same one — response may increase or decrease but depends

• many are normally stable or do not change (ex: synaptic transmission)

synaptic transmission

method by which a neuron communicates with another neuron (presynaptic → postsynaptic)

synapse

functional connection between a neuron and its effector, usually another neuron

• presynaptic releases neurotransmitter to engage receptors, causing an increase or decrease in postsynaptic excitability

• can be easier/faster or slow/blocked or acute/chronic

synaptic delay

the pause during the transfer of info from presynaptic cell to postsynaptic cell

• more neurons, longer reaction time

• ex: increase opening/closing of ion channels, increase transmitter removal

• need repeated use, training, and learning to increase strength

synaptic plasticity

the ability of synapses to strengthen or weaken over time, in response to increases/decreases in their activity

• important for learning and memory

• changes alter number of neurotransmitter receptors located

• dependent on CALCIUM RELEASE from postsynaptic

skeletal muscle

postsynaptic neuron integrates simultaneous inputs

• excitatory increase probability of postsynaptic neuron generating nerve impulse

• inhibitory decrease probability

• increase awareness facilitate input to neurons and reduce reaction time