Traffic - week 4 Flashcards
CNS is..
A “wired” system
- specific pathways for transmission of signals between areas of body
- In general, coordinates rapid, precise responses - interacts with endocrine system (“wireless”)
afferent (sensory) division
carries information toward CNS
Organization of nervous system
central nervous system (CNS) 1. brain and spinal cord - peripheral nervous system (PNS) 1. nerve fibers carry information between CNS and rest of body
efferent (motor) division
carries information away from CNS to effector organs (muscles, glands). somatic nervous system. autonomic nervous system.
somatic nervous system (somas)
motor neurons supplying muscles
autonomic nervous system (fight)
(1) innervates smooth and cardiac muscle, glands (2) sympathetic division (“fight or flight”)
(3) parasympathetic division (“resting and digesting”)
3 Classes of neurons (AIE)
AIE
afferent, efferent, interneurons (most)
afferent - where
AP, near spinal so friends with synapses in spinal cord
- in afferent division of PNS
- peripheral end has a sensory receptor
a. generates APs in response to a stimulus 3. cell body near spinal cord - synapses with other neurons in spinal cord
efferent (mec)
mec
- in efferent division of PNS
- cell body in CNS
- terminates at a muscle or gland
interneurons
- in CNS, between afferent and efferent
neurons 2. interconnect with one another. protection nourishment of brain
glial cells (neuroglia) supporting cells of CNS
EMOA
astrocytes, oligodendrocytes, ependymal cells, microglia
astrocytes (HSSTCCK)
HSSCCK (holds neurons, scar, synapse formation, changes in blood, communication, K+)
a. hold neurons together
b. repair of injury and scar formation
c. induce changes in blood vessels (blood-brain barrier) and participate in transport across barrier d. take up and break down some nts (glutamate, GABA)
e. take up excess K+ in ECF
f. enhance synapse formation and modify function, physical and chemical influences
g. communicate with each other and neurons via
gap junctions, nts, and other chemicals
oligodendrocytes
a. forms myelin sheaths
ependymal cells
CNS, CSF, stem cells
a. line internal cavities of CNS (ventricles of brain,
central canal of spinal cord)
b. help form cerebrospinal fluid (CSF)
c. serve as stem cells in some areas of brain
microglia
a. defense cells, can do phagocytosis b. secrete nerve cell growth factor
blood-brain barrier
- capillaries in brain have tight junctions joining cells
a. only substances that can pass through cells can be exchanged 2. protects brain from harmful substances - keeps out circulating hormones that act like nts
meninges: connective tissue membranes
dura mater (outer), arachnoid mater (middle), pia mater (inner)
dura mater
a. forms dural sinuses and venous sinuses (blood and CSF pool, return to circulation)
arachnoid mater
a. subarachnoid space contains CSF
b. arachnoid villi reabsorb CSF (return to blood
in sinuses)
pia mater (inner)
a. well vascularized
b. important in forming CSF
bones offer…
physical protection
cranium (skull) - brain and vertebral column - spinal cord
cerebrum
gray DNG, white myeline
- cortex is outer layer of gray matter (neuron cell bodies and dendrites, glial cells) DNG
- underneath is white matter (tracts of myelinated fibers), which transmits signals between cortical areas, and to other CNS locations
- divided into functional areas (some degree of overlap) specialized for particular activities, but no area acts alone
2 hemispheres
- connected by corpus callosum
- most functional areas occur in both hemispheres (except language areas)
- some degree of specialization
a. left and right right - generally contralateral
paired lobes parts
POFT
- occipital, temporal, parietal, frontal
- functional areas often contained within a lobe
3 kinds of functional areas of cortex
SAM
- motor areas - control voluntary motor functions
- sensory areas - conscious awareness of sensation
- association areas - integrate diverse information
primary visual cortex (selected functional area)
a. receives visual information
b. surrounding higher-order visual cortex interprets
primary auditory cortex (selected functional area)
a. receives information on sound
b. surrounding higher-order auditory cortex interprets
somatosensory cortex
receives touch, localizes, homunculous
a. receives sensory input (somesthetic sensations from skin like touch, temp. and proprioception, etc.)
(1) localizes source of input, perceives intensity of stimulus, capable of spatial discrimination
(2) sensory homunculus - a particular region of the brain receives information from a certain part of the body
posterior parietal cortex
cleaning up dishes
a. integrates somatosensory and visual input
b. important in complex movement
primary motor cortex
a. voluntary control of skeletal muscle
(1) motor homunculus - neurons controlling a particular body part tend to be grouped together
supplementary motor area
a. helps prepare “programs” for complex patterns of movement
premotor cortex
a. plans movement based on body orientation, coordination of complex movements
b. interacts with posterior parietal cortex
language areas
broca’s area, wernicke’s area
broca’s area
(1) important in ability to speak - interacts with motor
areas for speech
Wernicke’s area
(1) important in language comprehension (written and
spoken) and patterns of speech
Broca’s and Wernicke’s usually
in left hemisphere only, right side has affective language areas, which express and comprehend emotion in speech
prefrontal association cortex
a. plans for voluntary activities
b. weighing consequences, making choices c. personality
d. complex learning, intellect (cognition), conscience
parietal-temporal-occipital association cortex
integrates information from those lobes
limbic association cortex
MEM
motivation, emotion, memory
cortex displays plasticity
many areas can change based on need, e.g.:
a. other areas may take over for damaged areas b. use of a particular body part can result in more
cortical space being devoted to it - areas constantly interact
Subcortical structures
BHT
basal nuclei (basal ganglia), thalamus, hypothalamus
basal nuclei (basal ganglia) (mix)
- masses of gray matter within cerebral white matter
- functional clusters of cell bodies
- receives input from all cortical areas
- sends feedback via thalamus mainly to prefrontal and premotor areas (no direct connection to motor neurons)
thalamus
screens
1. preliminary processing of sensory input
a. screens out unimportant stimuli and passes on
significant input to somatosensory cortex and other brain regions contains many nuclei, each with a functional specialty
hypothalamus (short definition)
- many functionally grouped nuclei
2. integrating center for homeostasis, links ANS and endocrine system
limbic system
THCB
parts of cortex, basal nuclei, thalamus, hypothalamus
learning and memory
- learning: acquisition of knowledge or skills as a consequence of experience, instruction, or both
- memory: storage of knowledge for later recall
- remembering: process of retrieving information from storage - forgetting: inability to retrieve information
memory trace - what is it
neural change responsible for storage of information, cerebellum and hypocampus
- present throughout brain
- particular areas appear to be important in certain kinds of memories
memory (short term)
- short-term
a. immediately stored b. limited capacity
c. retrieved rapidly
d. forgetting is permanent (unless consolidated)
e. transient changes in preexisting synapses (changes in amount of nt released via modification of Ca2+ channels, may involve cAMP pathways)
long term memory
a. longer storage time, enhanced by practice b. large storage capacity
c. more slowly retrieved
d. quite stable, forgetting usually transient
e. permanent changes in neurons (formation of new synapses, synthesis of proteins in pre or postsynaptic membranes, changes in amount of nt released)
factors influencing consolidation (memory)
- emotional state-transfer better when more alert and motivated
- repetition
- association of new information with old information
cerebellum (BMCM)
BMCM
different portions specialize in particular functions (mostly ipsilateral)
1. maintains balance and equilibrium, important in movement
3. enhances muscle tone
4. coordinates and initiates voluntary movements
a. input from cortical motor areas and peripheral receptors (indirect)
b. ensures smooth, precise movement
a. output to cortical motor areas
6. procedural memories
brain stem - all incoming…
and outgoing fibers pass through, most synapse here for processing
functions of brain stem (breathe after hiccup)
cranial nerve origin
nuclei for cardiovascular and respiratory
- contains nuclei for control of autonomic activities
a. cardiovascular center (force and rate of
heart contraction, blood pressure)
b. respiratory centers (rate and depth of breathing)
c. many others such as vomiting, hiccuping, swallowing, coughing, sneezing
brain stem - pain (PERCSD)
PERCDS
- modulates pain
- regulates equilibrium and posture reflexes
- contains reticular formation
a. receives/integrates all synaptic input
b. controls cortical alertness (reticular activating system
- RAS)
c. direct attention - contains sleep centers
sleep
an active process in which an individual is not consciously aware of surroundings but can be aroused by external stimuli
types of sleep
slow-wave and paradoxical (REM) sleep
slow-wave sleep
a. from light sleep to deep sleep and back
b. characterized by frequent movement, small
decrease in heart and respiratory rate, and blood pressure
paradoxical (REM) sleep
a. brain activity similar to awake state
b. characterized by lack of movement (except eyes),
irregular heart and respiratory rate and blood pressure, dreaming
1. time to restore chemical/physiological processes
2. accomplish changes for learning and memory
spinal cord
extends from brain stem - has paired spinal nerves 1. serves a particular body region 2. both afferent (sensory) and efferent(motor and ANS) fibers
gray matter is found in (DNGS - VDL)
- neuron cell bodies and dendrites, short interneurons, glial cells DSNG
- dorsal horns
- lateral horns
- ventral horns
white matter (directions of movement)
fiber tracts
a. ascending: cord ➝ brain
b. descending: brain ➝ cord
reflexes
response that occurs without conscious effort and reflex arc: the neural pathway involved
response that occurs without conscious effort (consciousness is simply acquired)
a. simple (basic): built-in, unlearned (e.g.,pulling away from a painful stimulus)
b. acquired (conditioned) : learned through practice (e.g., typing, playing sports)
reflex arc
a. receptor responds to stimulus by generating an AP
b. afferent pathway relays information to…
c. integrating center (spinal cord or brainstem for
simple reflexes, higher brain levels for acquired
reflexes)
d. efferent pathway transmits information to… e. effector (muscle or gland)
spinal reflexes
Eii
spinal cord is integrating center (no brain involvement needed)
b. afferent pathway terminates on three types of neurons:
(1) excitatory interneuron,
(2) inhibitory interneuron,
(3) interneurons carrying signal to brain (person becomes aware of stimulus)
excitatory interneurons stimulate (spinal reflex)
efferent motor neurons (muscle contracts)
inhibitory interneuron (spinal reflex)
which inhibits efferent motor neurons leading to antagonistic muscle group (called reciprocal inhibition or innervation)
interneurons carry…(spinal reflex)
signal to brain (person becomes aware of stimulus)
brain can modify spinal reflex…
inhibit overrides excitatory
consciously override by sending inhibitory
signals to muscle group that would move to an excitatory signals to antagonistic muscle group
dorsal horns (alf ends)
a. cell bodies of interneurons b. afferent neurons terminate
lateral horns
a. efferent autonomic (ANS) cell bodies
ventral horns
a. efferent motor (somatic) neuron cell bodies
left hemisphere
logical, analytical tasks like language ,math; fine motor control
right hemisphere
non language skills like spatial perception and art/music
substances that can get through the blood brain barrier
through blood vessels. lipid soluble substances, e.g., O2, CO2, alcohol, steroid hormones; substances with specific carriers, e.g., glucose, amino acids, ions
functional parts of cell bodies (in basal nuclei) (MMMCC)
a. inhibiting muscle tone
b. maintaining purposeful motoractivity and
suppressing unnecessary movement
c. monitor/coordinate muscle contractions
in posture/support
d. complex aspects of motor control
e. may be involved in cognitive functioning
contains “reward” and “punishment” centers
limbic
important in homeostatic drives - hunger, thirst, sex
limbic
norepinephrine, dopamine and serotonin…
important neurotransmitters (precise role unclear, more of these nts associated with pleasure, less with depression) in limbic
crude awareness of sensation
thalamus
reinforces voluntary motor activity
thalamus
some degree of consciousness
thalamus
“gateway”to cerebral cortex-virtually all inputs to cortex pass through
thalamus
memory trace in hippocampus
SCD
short term, consolidation, declarative memories
memory trace in cerebellum
procedural memories (a.k.a.skill memories involving motor pathways, e.g., playing piano, typing, riding a bike)
regulates body T (monitors blood temperature)
hypothalamus
regulates water balance (urine output) and thirst (contains osmoreceptors - test concentration of body fluids)
hypothalamus
regulates food intake (monitors blood levels of nutrients and hormones)
hypothalamus
controls endocrine functioning (produces hormones, regulates pituitary)
hypothalamus
role in emotional and behavioral patterns
hypothalamus
controls autonomic centers in brain and spinal cord (e.g., activity of smooth and cardiac muscle, exocrine glands)
hypothalamus
“biological clock”
hypothalamus
centers that control REM sleep (arouse from sleep)
probably 3 centers that interact to produce the stages of sleep (arousal system, slow wave center, REM center) - functions
involved in all aspects of emotion (pleasure, fear, anger, etc.) and physical expressions of emotion (attacking when angered, laughing, crying, etc.)
limbic
brain tissue is only…
nervous tissue
CSF…(chords)
- formed by choroid plexuses, surrounds brain and spinal cord
- cushions CNS
- it is the interstitial fluid of the CNS
a. directly contacts CNS cells and exchanges take
place - similar to plasma, but lower in K+ and higher in Na+
gyri
bumps
sulci
grooves
homunculus
map of body on brain
split brain patients
cannot verbalize the image because language is in the left hemisphere.
stroke on left side
left somatosensory and left primary motor cortex, and broca’s area
how eye drops affect the autonomic
adrenergic drug cause pupil to contract via sympathetic. cholinergic blocking drug cause dilation by blocking sympathetic.
chest pain during excercise
drugs that block B1 receptors interfere w/ sympathetic stimulation. prevents increased cardiac metabolism and reduces angina.
bladder question
external urethra is skeletal muscle - controlled by somatic, bladder is smooth muscle - autonomic.
