How can we help?

You can also find more resources in our Help Center.

150 terms

Central Nervous System, Sensory Systems, Efferent Systems of the Peripheral Nervous System

STUDY
PLAY
acetylcholine (ACh)
- neurotransmitter released from all autonomic preganglionic fibers, parasympathetic postganglionic fibers, and motor neurongs
vitreous humor
- jelly-like substance in the posterior cavity of the eye between the lens and retina
stereocilia
- auditory and vestibular hair cells that transduce mechanical movements into electrical signals
Sensory/Motor maps
- different regions of the body are represented differently in the brain
- certain regions take up much larger space in brain
association cortex
- involved in higher levels of processing
glial cells
- support neurons physically and metabolically; astrocytes, oligodendrocytes, microglia, ependymal cells
- brain tumors are a result of improper division
cerebrospinal fluid (CSF)
- bathe the brain and spinal cord
- made up of astrocytes that limits the exchange of materials which forms the blood-brain barrier
3 types of memory
- short-term
- long-term
- working
spinal reflexes
- information does not need to reach cortex (reflex arc)
receptors
- pick up sensations from the environment
transduction
- change of physical parameter into membrane voltage; causes receptor potentials and initiates APs
sensory pathway
receptor -> transduction -> receptor potential
receptive fields
- smaller fields lead to greater acuity
- discriminative ability to discern between two different points of stimulation
labeled line of sensory system
- receptors transmit signals to specific region of the cortex
types of pain receptors
- bony nerve endings called nociceptors; mechanical, thermal, polymodal
types of axon fibers in pain
A-delta fibers
- small, myelinated fibers; fast pain (prick)
C fibers
- unmyelinated fibers; slow pain (dull)
rods
- work in low light levels and gray-scale; high surface area
cones
- work in high light levels; small surface area
short wavelength - blue
middle wavelength - green
long wavelength - red
determination of color by cones
- each type of cone has a different absorption spectrum
magnocellular parallel pathway
- big cells
- fast processing (shape, motion, big picture)
- retina feeds into it
parvocellular parallel pathway
- small cells
- detail (color, texture)
- retina feeds into it
crossing of visual information
- left visual field projects to right side of the brain; right to left side
- crossing occurs at optic chiasm above the thalamus
receptive fields of retinal ganglion cells
on-center
off-surround
receptive fields of visual cortex
simple cells: on-middle, off sides
complex cells: on, off-each side; edge detector
depth perception
- in focus image lies on same points in both retinas
- when further or closer than focal plane, there is disparity in position of object between two retinas
middle ear
- transmits sound from eardrum to inner ear
middle ear bones (ossicles)
- malleus (hammer)
- incus (anvil)
- stapes (stirrup)
oval window - connection between middle/inner ear
discrimination of pitch/amplitude
- different portions of cochlea vibrate in response to different frequencies (low further from oval window)
- amplitude determined by the amount of vibrations coming through
detection of rotational acceleration in head
3 semicircular canals
- filled with fluid that move
- detected by hair cells embedded in cupula in ampulla
chemical sense detect presence of odorants/tastants
taste buds
- taste pore that allows entrance of testant molecule
- receptor cells respond to a single taste
odorants
- different receptor for every smell
info sent to cortical gustatory area in parietal lobe of cortex
organophosphates
- inhibits acetylcholinesterase activity
curare
- blocks ACh receptors
botulism toxin
- inhibits ACh release (relaxes muscles)
black widow spider toxin
- causes massive release of ACh from NMJ (muscle contraction)
Sympathetic/Parasympathetic
Positions where fibers emerge from spinal cord
Symp - nerves exit middle of spinal cord
Para - nerves exit from top/bottom of spinal cord
Sympathetic/Parasympathetic
Situations in which they are active
Symp - "Fight or flight" responses
Para - relaxed situations
Sympathetic/Parasympathetic
Effects on Organs
Symp - increase HR, BP, release of glucose from stores; decrease digestive/urinary function
Para - opposite effects of sympathetic system
Autonomic Nervous System
- controls most involuntary organ activities; sympathetic and parasympathetic
Output Organs for the PNS
Movement - muscle
Secretion - exocrine/endocrine glands
rhodopsin
- photopigment in rods
slow pain pathway
- impulses from polymodal receptors that respond to chemical receptors are carried by small, unmyelinated C fibers
tastant
- taste-provoking chemical
taste buds
- 50 long, spindle-shaped taste receptor cells packaged with supporting cells
taste pore
- small opening in taste bud through which fluids in the mouth come in contact with the surface of its receptor cells
tone
- pitch of sound
NMJ
- juncture between a motor neuron and a skeletal muscle fiber
motor end plate
- part of a skeletal muscle fiber that lies beneath the terminal button of the motor neuron and has receptor sites for binding ACh
agonists
- substance that binds to a neurotransmitter's receptors and mimics the neurotransmitters response
end-plate potential
- graded receptor potential that occurs at the motor end plate of a skeletal muscle fiber in response to binding with ACh
cholinergic fibers
- nerve fibers that release ACh as their neurotransmitter
adrenergic fibers
- nerve fibers that release norepinephrine as their neurotransmitter
somatic sensation
- sensory information arising form the body surface; somesthetic and proprioceptive input
Steps of Phototransduction
1. light hits rhodopsin
2. conformation change 11-cis retinal to all trans-retinal
3. all-trans retinal activates transducin
4. transducin causes activation of a PDE
5. PDE cleaves cGMP
6. cGMP-gated Na+ channels close due to lack of cGMP
7. photoreceptor hyperpolarizes
8. photoreceptor decreases release of glutamate from synaptic terminal
sclera
- visible, white, outer layer of the eye
otoliths
- sense organs in the inner ear that provide information about rotational changes in head movement; utricle and saccule
organ of Corti
- sense organ of hearing within the inner ear
chemoreceptors
- sensory receptor sensitive to specific chemicals
somatosensory cortex
- site of initial processing of somesthetic and proprioceptive input
somatic nervous system
- innervates skeletal muscles; consists of axonal fibers of alpha motor neurons
hippocampus
- portion of the temporal lobe that is crucial for forming long-term memories
frontal lobes
- responsible for voluntary motor output, speaking ability, and elaboration of thought
kinocilium
- the one cilium in a vestibular hair cell
Wernicke's area
- concerned with language comprehension
epilepsy
- large number of neurons undergo abnormal, synchronous APs that produce involuntary spasms
dorsal root
- where afferent fibers carrying incoming signals from peripheral receptors enter the spinal cord
dorsal horn
- contains cell bodies of interneurons on which afferent neurons terminate
consolidation
- process of transferring and fixing short-term memory traces into long-term stores
amygdala
- processes inputs that five rise to the sensation of fear
sensory afferent
- pathway into the CNS carrying information that reaches the level of consciousness
retina
- innermost layer in the posterior region of the eye that contains photoreceptors (rods/cones)
photoreception
- sensory reception response to light
perception
- conscious interpretation of the external world created by the brain from a pattern of nerve impulses
oval window
- membrane covered opening separating the middle ear from the inner ear
optic nerve head
- nerve fibers leaving the retina that relay information about visual input
lateral inhibition
- most strongly activated signal pathway originating from the center of a stimulus area inhibits the less excited pathways from the fringe areas
cochlea
- snail-shaped portion of the inner ear that houses the receptors for sound
analgesic systems
- pain relieving
temporal lobes
- process auditory input
somatic cells
- body cells
reflex
- response that occurs automatically without conscious effort
PNS
- nerve fibers that carry information between CNS and other parts of the body
parietal lobes
- contain somatosensory cortex
occipital lobes
- process visual input
nerve
- bundle of peripheral neuronal axons, afferent and efferent
dorsal root ganglion
- cluster of afferent neuronal cell bodies adjacent to the spinal cord
effector organs
- muscles or glands innervated by the nervous system that carry out the nervous system's orders to bring about a desired effect
efferent division
- portion of the PNS that carries out instructions to effector organs from the CNS
cognition
- act of "knowing"; awareness and judgement
CNS
- brain and spinal cord
amnesia
- lack of memory that involves whole portions of time; retrograde (past events) and anterograde (inability to consolidate information for long-term use)
emotion
- encompasses subjective emotional feelings and moods
morphine
- powerful analgesic; part of the opium poppy
fast pain pathway
- small, myelinated A-delta fibers that carry pain signals
working memory
- briefly holds and processes data for immediate use (both new and old information)
neuroendocrinology
- study of relationships between the nervous and endocrine systems
motor neurons
- innervate skeletal muscle and their axons constitute the somatic nervous system
sympathetic ganglion chain
- located along either side of the spinal cord and is location of postganglionic neurons
visual system functioning as a 10 log-unit range
- changes visual sensitivity to prevent response saturation while keeping contrast sensitivity constant
Sympathetic/Parasympathetic
Neurotransmitters Used
Symp - preganglionic - Acetylcholine, postganglionic - Norepinephrine
Para - pregangionic/postganglionic - Acetylcholine
Sympathetic/Parasympathetic
Types of Receptors Triggered
Symp - alpha1/beta1 - excitatory, alpha2/beta2 - inhibitory
Para - nicotinic, muscarinic
Sympathetic/Parasympathetic
Location of Ganglia
Symp - collateral ganglia - halfway between CNS and innervated organs
Para - terminal ganglia - in or near effector organs
Steps by which activation of somatic nervous system leads to muscle contraction
1. Motor neuron axons terminals release ACh
2. Excitation/contraction of innervated muscles
3. Motor neurons can only stimulate skeletal muscles
corpus callosum
- thick band of nerve fibers that connects the two cerebral hemispheres structurally and functionally
efferent neurons
- found in PNS and originate from the CNS
afferent neurons
- found in PNS and send sensory information to the brain
Hemispheres
left - detail stuff
right - big picture stuff
Cerebral Cortex Layers
Upper - gray matter
Lower - white matter
Cerebral Cortex Neuron types
stellate cells - small dendritic and axonal fields
pyramidal cells - longer axons, send information out of cortical column
Cerebral Cortex Lobes
occipital - primary visual cortex
temporal - primary auditory cortex
parietal - primary somatosensory cortex
frontal - primary motor cortex
hair cells of cochlea transduce information
- when hair cells bend to stereocilium, mechanically gated channels are opened causing inflow of K+
outer ear
- pinna
- ear canal
- tympanic membrane (eardrum)
phasic receptors
- rapidly adapting response
tonic receptors
- slowly adapting response
primary cortex
- responsible for voluntary motor ouptut
Aplysia
habituation - tune out working stimulus
sensitization - respond quicker 2nd time
cerebral cortex language ability
Broca's - speaking ability
Wernicke's - comprehension
acquisition of memory
- consolidation
- change in synaptic efficiency - short term
- change in synaptic connections - long term
limbic system
- controls behavior, motivation
amygdala - fear
astrocytes role in blood-brain barrier
- surround blood vessels in bran and limit exchange of materials
ependymal cells
- stem cells; new glia and neurons, active in hippocampus
microglia
- immune cells of brain
astrocytes
- hold neurons in proper spatial relationship
- guide neurons during development
- form blood-brain barrier
- repair injuries
interneurons
- lie between efferent and afferent neurons and important in integration/processing of life
pons
- relays signals from the forebrain to the cerebellum
midbrain
- associated with vision, hearing, motor control
aphasia
- language disorder caused by damage to cortical areas
capsaicin
- activates peripheral receptors of afferent C fibers
mitral cells
- in olfactory pathway
myopia
- nearsightedness
diencephalons
- consists of thalamus and hypothalamus
proprioception
- awareness of position of body parts in relation to one another and surroundings
accomodation
- ability to adjust the strength of the lens in the eye so that both near and far sources can be focused on retina
basilar membrane
- forms the floor of the middle compartment of the cochlea and bears the organ of Corti
receptor potential
- graded potential change that occurs in a sensory receptor in response to a stimulus
acetylcholinesterase (AChE)
- enzyme that inactivates ACh
adrenal medulla
- secretes hormones epinephrine/norepinephrine into the blood in response to sympathetic stimulation
inner ear
cochlea
- scala tympani - outside of coil
- scala vestibuli - inside of coil
- cochlear duct
pain neurotransmitters
- substance P
- glutamate
cerebellum components
vestibulocerebellum - balance
spinocerebellum - coordination of complex movements
cerebrocerebellum - planning movements
thalamus
- relay/integratoin station for sensory inputs
- controls attentions
oligodendrocytes
- form myelin
meninges
three membranes that wrap CNS
- dura mater
- arachnoid mater
- pia mater
prostaglandins
- local chemical mediators
memory mediated by...
- hippocampus, cerebellum, prefrontal cortex
hypothalamus
- regulates internal environment; homeostasis
brain stem
- centers for life support systems
cerebrum
- consists of basal nuclei and cerebral cortex
medulla
- deals with involuntary functions
subcortical structures
- basal nuclei, thalamus, hypothalamus
basal nuclei
- motor control
opiate receptors
- inhibitory interneurons release enkaphalin at the pain-fiber terminal and bind with these