final Flashcards
Chemical gated channel
Neurotransmitters bind to receptor which opens channel and allows Na+ in.
Voltage gated channel
channels open and close in response to changes in the membrane potential
depolarization
membrane potential moved toward 0 mV, inside becomes less negative/more positive. On chart it slightly increases. Na+ flowing into cell. Increases the probability of producing nerve impulses
hyperpolarization
membrane potential increases, inside becomes more negative. On chart, it slightly decreases. Decreases the probability of producing nerve impulses. K+ leaving the cell
repolarization
Occurs when K+ flows out of the cell
action potential order
Resting state Depolarization Repolarization Hyperpolarization
Resting state
no ions move through voltage gated channels
absolute refractory period
The period from opening of the Na+ channels until the Na+ channel begin to reset to their original resting state
relative refractory period
: Interval where most Na+ channels have returned to their resting state, some K+ channels are open and repolarization occurs
saltatory conduction
When action potentials are only triggered at the gaps
synapse
a junction that mediates information transfer from one neuron to the next or from a neuron to an effector cell
Neurotransmitters
Chemical messenger released by neurons that may stimulate or inhibit those neurons or effector cells. Must bind to receptors of neurons or effector cells
EPSPs
- Excitatory Postsynaptic Potential
- local graded depolarization event
IPSPs
- Inhibitory Postsynaptic Potentials
- Hyperpolarizing changes in action potential
temporal summation
2 excitatory stimuli close in time cause EPSPs that add together
spatial summation
2 simultaneous stimuli at different locations cause EPSPs that add together
cerebral cortex lateralization
Each hemisphere of the brain having a specific ability that it doesn’t share with the other hemisphere
cerebral cortex dominance
left side is dominant for language and right side is musical and artistic
cerebral white matter
Consists mostly of myelinated fibers bundled into large tracts. Provides for communication between cerebral areas and lower CNS centers
basal nuclei
Specific gray matter areas located deep within the white matter of the cerebral hemispheres
thalamus
A mass of gray matter in the diencephalon. This is the relay station for information coming into the cerebral cortex. Information is sorted out and “edited.” Impulses from all senses and all parts of the body converge on the thalamus
hypothalamus
Main visceral control center of the body, vitally important to overall body homeostasis. Controls ANS, initiates physical responses to emotions, regulates body temp, regulates food intake, regulates water balance and thirst, regulates sleep-wake cycles, controls endocrine system function
epithalamus
Secretes melatonin, regulates sleep-wake cycle
midbrain
located between diencephalon and pons
pons
Bulging brain stem region between midbrain and medulla oblongata. Composed of motor and sensory conduction tracts.
medulla oblongota
Form 4th ventricle with pons. Also composed of fiber tracts
anterior root
motor root
posterior root
sensory root
ascending columns
- tracts bringing info to the higher centers
- Dorsal white column, posterior spinocerebellar tract and anterior/lateral spinothalamic tract
descending columns
Tracts bringing info to the cord from the brain or within the cord to lower levels
Tectospinal tract, vestibulospinal tract, medial reticulospinal tract
monosynaptic reflexes
a single synapse between a sensory neuron and a motor neuron
polysynaptic reflex
multiple synapses with chains of interneurons
stretch reflex
Makes sure that the muscle stays at that length (patellar or knee jerk reflex)
flexor reflex
Causes automatic withdrawal of the threatened body part of the stimulus. Happens when you hurt yourself
crossed extensor reflex
This is accompanied by the flexor reflex in weight bearing limbs. Like when you step on glass bare foot
contralateral
opposite
ipsilateral
situated on the same side
CSF Flow
- lateral ventricle
- interventricular foramen
- third ventricle
- cerebral aqueduct
- fourth ventricle
- central canal
- arachnoid villus
ANS
: consists of visceral motor nerve fibers that regulate activity of smooth muscles, cardiac muscles and glands (involuntary nervous system)
SNS
Composed of somatic motor nerve fibers that conduct impulses from the CNS to skeletal muscles (voluntary nervous system)
preganglionic neurons
reside in brain or spinal cord
postganglionic neurons
reside in an autonomic ganglion outside the CNS
Neurotransmitter sympathetic
norepinehrine (NE)
Fight or flight
sympathetic
effects of sympathetic on body
Help us when we are in an emergency or threatening situation. Heart rate increases, deep breathing, dry mouth
rest and digest
parasympathetic
neurotransmitter for parasympathetic
ACh
effects in body of parasympathetic
conserves and stores energy
maintenance function
antagonistic action
seen on the activity of the heart, respiratory system, and gastrointestinal system. Example: heart rate increases during fight or flight, then decreases after emergency
cooperative action
example: PS dilates blood vessels and produces erection of male penis then the S causes ejaculation of semen
