3.3-3.4 Nervous system Flashcards
PNS
sensory function of nervous system; receives info
CNS
the integrative (processing) of information
consists of spinal cord and brain
motor/motor neurons
acting on information; motor neurons carry information from CNS to organ that can act, known as effectors
types of effectors
muscles and glands
efferent vs afferent
efferent neurons -> go AWAY from CNS
sensory neurons -> afferent, carry to CNS
eff-ing leave to the effectors; efferent goes to effectors
aff -> attract sensory info; requires thinking affterwards
monosynaptic reflex arc
a quadricep muscle contracts when the patellar tendon is stretched (involves two neurons and 1 synapse)
inhibitory interneuron
a short neuron which forms an inhibitory synapse with a motor neuron (ex. in the hamstring muscle); the concurrent relaxation of hamstring and contraction of quadriceps is an example of reciprocal inhibition
reciprocal inhibition
concurrent relaxation of the hamstring and contraction of the quadriceps
somatic vs autonomic
somatic = voluntary (skeletal muscles)
autonomic = “automatic” (digestions, metabolism, circulation, perspiration, etc)
autonomic divides into two halves
sympathetic/parasympathetic
sympathetic versus parasympathetic
(memorize the table)
what are neuronal cell bodies called outside of the CNS?
ganglia, which are bunches of somas located OUTSIDE the CNS
“the gangs are outside roaming the streets”
where are most neuronal cell bodies found?
majority are found in the CNS, sometimes bunched in structures called nuclei
3 main parts of the brain
hindbrain (rhombencephalon)
midbrain (mesencephalon)
forebrain (prosencephalon)
HMF
CSF
a clear liquid that 1. absorbs shocks/protects spinal cord, 2. exchange nutrients and waste
spinal cord
simple spinal reflexes, primitive processes like walking, urination, and sex organ function
hindbrain
medulla, pons, cerebellum (“little brain”)
medulla (oblongata)
located below the pons, connects to spinal cord (“obligated to spinal cord”).
- autonomic functions (bp/digestion/vomiting)
- respiratory function (“obligated to breath and digest and vomit”)
pons
below the midbrain
- some autonomic functions
- coordinates movements
- balance/antigravity
“ponsford teaches balance to astronauts”
cerebellum
“little brain”
- complex movements
- instructions for movement from forebrain are sent to cerebellum
- hand-eye coordination and balance
- receives input from the vestibular apparatus
midbrain
- visual/audio information
- Reticular activating system (RAS) -> wakefulness, arousal
“mid-night wakefulness, listening to music and watching videos”
brainstem
medulla + pons + midbrain
forebrain
diencephalon, telencephalon
diencephalon
thalamus + hypothalamus
thalamus
relay-processing for sensory information
hypothalamus
- emotions
- autonomic functions
- hormone production and release
- link between nervous and endocrine systems
- controls the pituitary
telencephalon
- divided into two symmetrical sides
- left-side is dominant, speech
- right-side is concerned with visual-spatial reasoning and music
corpus callosum
bundle of axons connecting the two sides of telencephalon
cerebrum
made of two cerebral hemispheres
- grey outer cortex (trillions of somas)
- white inner core connected to diencephalon (composed of myelinated axons)
- the cerebral hemispheres process somatic sensory information and motor information
4 lobes of cerebral cortex
frontal, parietal, temporal, occipital
DRAW
frontal lobes
voluntary movement
- complex reasoning and problem-solving
parietal lobes
sensation (touch, temperature, pressure, vibration) and gustation
“parents teach sensations and taste”
temporal lobes
auditory and olfactory
- short-term memory, language comprehension, emotion
“temporary sounds and smells”
occipital lobes
visual sensation
“watching occi-clean commericals”
basal nuclei
aka basil ganglia = movement
- voluntary motor control and habits
- works with cerebellum to coordinate movement initiated by the primary motor cortex
- basil nuclei are inhibitory, cerebellum is excitatory
limbic
- between cerebrum and diencephalon
- substructures include: amygdala, cingulate gyrus, hippocampus
- emotion/memory/learning
Page 55 table
MEMORIZE TABLE
homunculus
little man
neurons entering/exiting the CNS
carried by 12 pairs of cranial nerves
31 pairs spinal nerves
Cranial nerves -> sensory and motor information to and from the brainstem
Spinal nerves -> to and from spinal cord
vagus nerve
the 10th cranial nerve
- decreases heart and increases GI tract
- parasympathetic
- axons synapse at ganglia on the heart, stomach, and other visceral organ
- nerves are preganglionic and located in CNS
- they synapse with postganglionic neruons
somatic PNS anatomy
- innervate skeletal muscles
- ACh is NT
- cell bodies live in brain stem or ventral portion of spinal cord
dorsal root ganglion
located just outside the CNS, a bunch of somatic (and autonomic) sensory neuron cell bodies (contains the cell bodies of afferent neurons)
- protected by vertebral column, but outside the meninges, thus out of the CNS
- sometimes synapse on the cord, sometimes stretches to the brain stem
parasympathetic postganglionic neurons release…
acetylcholine
acetylcholine = parasympathetic system
sympathetic postganglionic neurons release…
norepinephrine
norepinephrine stimulates
where are the preganglionic efferent neurons of the sympathetic system?
all sympathetic preganglionic efferent neurons have cell bodies in the thoracic or lumbar regions of spinal cord
- the sympathetic system = “thoracic-lumbar system”
what is the parasympathetic system also known as?
the craniosacral system. all the preganglionic neurons have cell bodies in the brainstem or or sacral portion
Illustration autonomic nervous system (p. 58)
DRAW
where is the first synapse of the somatic afferent neuron?
in the CNS
“short reflex”
autonomic afferent neurons can synapse in the PNS (at the autonomic ganglia) with autonomic efferent neurons
Table of sympathetic versus parasympathetic (p. 59)
DRAW
adrenal cortex
secretes glucocorticoids, mineralocorticoid (aldosterone), and sex hormones
adrenal medulla
- sympathetic nervous system
- embryologically derived from sympathetic postganglionic neurons
- innervated by sympathetic preganglionic neurons
- releases epinephrine
