subdivisions of the Nervous System Flashcards
5 major areas of the CNS
- telencephalon
- cerebellum
- diencephalon
- brainstem
- spinal cord
3 parts of the brainstem
- midbrain
- pons
- medulla
where is the cerebral cortex situated
telencephalon
corpus callosum
interconnects two cerebral hemispheres
where are the basal ganglia situated
telencephalon
function of basal ganglia (group of subcortical nuclei)
involved in motor control
4 parts of basal ganglia
- striatum
- globus pallidus
- amygdala
- hippocampal formation
function of amygdala
participates in the expression of emotion
function of hippocampal formation
formation of new memories
3 parts of the cerebellum
- vestibulocerebellum (archicerebellum)
- spinocerebellum (paleocerebellum)
- cerebrocerebellum (neocerebellum)
function of vestibulocerebellum
maintain the body’s balance
function of spinocerebellum
regulate muscle tone
function of cerebrocerebellum
coordinate motor behavior
what does is mean when output reaches the contralateral motor cortex
it reaches the opposite side of the body
3 parts of the diencephalon
- thalamus
- subthalamus
- hypothalamus
what is the thalamus the main integrating station for
sensory information
which two functions also reside in the thalamus
- control of arousal
- memory function
what does the thalamus receive along with the subthalamus
projections from the basal ganglia that are important for motor function
which disease can someone devellop when there’s no normal motor control
Parkinson disease
what does the hypothalamus affect
the ANS
which 2 types of hormones does the hypothalamus synthesize (it acts as part of the endocrine system)
- certain hormones that are transported down their axons to the posterior pituitary gland
(e. g. vasopressin, oxytocin) - releasing hormones (e.g. gonadotropin-releasing hormone) that are released into a portal
system that carries them to cells in the anterior pituitary
4 important elements in which the hypothalamus plays an important role
- hunger
- thirst
- body temperature
- cardiovascular system
what are the nerves called through which the brainstem sends motor signals
cranial nerves
reticular formation
a set of interconnected nuclei that are located throughout the brainstem
what does the reticular formation affect
the level of consciousness or arousal
main controls of midbrain
- eye movement (CN III, CN IV)
- relaying signals related to hearing and vision
5 functions of pons
- mastication (CN V)
- eye movement (CN VI)
- facial muscles (CN VII)
- sensory information from face, scalp, mouth and nose (CN V)
- processing info related to hearing and equilibrium (CN VIII)
which muscles do the somatic motor neurons of the medulla innervate
- muscles of the neck (CN XI)
- muscles of the tongue (CN XII)
what 4 elements does the medulla control along with the pons (CN IX , X)
- blood pressure
- heart rate
- respiration
- digestion
of how many segments that each have a motor and sensory nerve root does the spinal cord consist
31 elements
from which 3 elements does sensory information enter the spinal cord
- skin
- muscle
- visceral organs
dorsal roots
fascicles of axons through which sensory information enters the spinal cord
where do the cells bodies of dorsal root axons have their origin
spinal ganglia
do ventral roots contain stricly efferent or afferent fibers?
efferent
3 types of interactions from incoming sensory fibers when they enter the spinal cord
- segmental reflex
(synapse directly on motor neurons in that same segment) - intersegmental reflex
(synapse with neurons in other spinal segments) - suprasegmental reflex
(travel rostrally to brainstem before they synapse)
ascending tracts
sensory info,
descending tracts
motor info
most important descending tract
lateral corticospinal tract (almost all cell bodies have contralateral cerebral cortex as origin)
which 2 divisions does the PNS have
- somatic (deals with body’s external environment)
- autonomic (deals with body’s internal environment)
2 elements somatic division of PNS
- sensory neurons and axons that innervate skin, joints and muscle
- motor axons that innervate skeletal muscle
autonomic portion of PNS
consists of motor and sensory axons that innervate smooth muscle, exocrine glands and other viscera
4 main purposes of PNS
- transduce physical/chemical stimuli into raw information through receptors
- convey sensory information to CNS along axon pathways
- convey motor signals from CNS along axon pathways to target organs
- convert motor signals to chemical signals
peripheral nerves
bundles of organized axons in the PNS
endoneurium
loose connective tissue that surrounds individual axons
perineurium
connective tissue that covers fascicles
fascicle
small groups of bundled axons
epineurium
matrix of connective tissue that surrounds fascicles
nerve plexus
branching network of intersecting nerves
dermatome
area of skin in which sensory nerves derive from a single dorsal root and its ganglion
why does severing a single dorsal root not produce anesthesia in that dermatome
there’s an overlap between the cutaneous innervation provided by adjacent dorsal roots
which root will produce anesthesia if severed
C2 root (back of the head)
3 divisions of the ANS
- sympathetic
- parasympathetic
- enteric
where does the enteric division of the ANS lie
PNS
what do the sympathetic and parasympathetic divisions of the ANS innervate
most visceral organs (they have a yin-yang functional relationship)
