structure and function of the neurologic system Flashcards
components of the central nervous system
brain and spinal cord
components of the peripheral nervous system
cranial nerves and spinal nerves
what two nervous systems are within the peripheral nervous system
somatic and autonomic
the somatic nervous system has motor and sensory pathways that regulate ______ motor control of skeletal muscle
voluntary
the ____ nervous system has motor and sensory pathways that regulate the body’s internal environment and involuntary control of organ systems
autonomic
what two systems are within the autonomic nervous system
- sympathetic (fight-or-flight)
- parasympathetic (rest-and-secrete)
____: primary information and communication cell
neuron
______: receptive portion of the neuron
dendrites (dendritic zone)
the cell body of a neuron in the CNS = ______
nuclei
groups of cell bodies in the PNS = __________
ganglia and plexuses
________: sending portion of the neuron that leave from the cell body
axons
neurons generate and conduct electrical and chemical impulses and influence other nearby neurons by the release of ________
neurotransmitters
when a membrane potential is raised sufficiently what occurs
an action potential (impulse)
(all-or-none response; nothing happens before the membrane potential is reached)
_____: beginning of nerve impulse
axon hillock
the _____ is a segmented, insulating lipid layer over an axon
myelin sheath
(help make the action potential move faster)
the myelin sheath is formed and maintained by what
- schwann cells (peripheral nervous system)
- oligodendroglia (central nervous system)
______: cells that support the function of nerve cells
neuroglia
(5-10x more numerous than neurons)
______: support cells that fill the spaces between neurons and surround the blood vessels in the CNS
astrocytes
________: support cells that deposit myelin within the CNS
oligodendroglia
_______: support cells that remove debris in the CNS
microglia
_________: support cells that line the cerebrospinal fluid-filled cavities of the CNS
ependymal cells
_______: spaces between neurons that allow connection and communication
synapses
impulses are transmitted across the synapse by ______ conduction
chemical (neurotransmitters) and electrical
(norepinephrine, acetylcholine, dopamine, histamine, serotonin)
neurotransmitters are stored by synaptic boutons and released across the ______, which is the space between neurons
synaptic cleft
what does regeneration depend on
location, type of injury, inflammatory response, scar tissue formation
what is wallerian degeneration
death of nerve tissue (distal end of axon)
name the steps of regrowth in the proximal end of the myelinated nerves in PNS
- Swelling and dispersal of the Nissl substance
- Cell increases metabolic activity, protein synthesis, and mitochondrial activity
- New terminal sprouts project from the proximal segment
name the three major divisions in the brain
- forebrain (multiple parts)
-Midbrain (corpora quadrigemina, tegmentum, and cerebral peduncles) - Hindbrain (cerebellum, pons, and medulla)
what three parts does the brainstem consist of
- midbrain
- medulla
- pons
______: network of connected nuclei that regulate vital signs and maintains wakefulness
reticular formation
the reticular formation and the cerebral cortex and together referred to as _________
reticular-activating system
what does the forebrain consist of (8)
- cerebrum
- frontal lobe
- parietal lobe (somatic sensory input)
- occipital lobe (vision)
- temporal lobe
- corpus callosum
- limbic system
- diencephalon
name the 4 components of the frontal lobe
- Prefrontal (thoughtful, goal-oriented behavior; short-term or recall memory)
- Premotor (programs automatic/autonomic motor movement; basal ganglia (extrapyramidal sys.)
- Primary motor area (main voluntary motor area; efferent nerves [away from brain])
- Broca speech area (motor aspect of speech)
_______: behavioral response to emotions, motivation, mood, biologic rhythms, smell, memory
limbic system
what are the four components of the diencephalon
- epithalamus (vital and visceral functions)
- thalamus (wakefulness/learning)
- hypothalamus (internal environment/emotive behavior)
- subthalamus (motor function)
name the three components of the midbrain
- corpora quadrigemina/tectum (superior colliculi); inferior colliculi
-tegmentum - cerebral aqueduct
name the two components of the tegmentum in the midbrain
- red nucleus (motor output)
- substantia nigra (synthesizes dopamine)
what portion of the midbrain is responsible for parkinson’s disease
substantia nigra in the tegmentum
name the three components of the hindbrain
- cerebellum
- pons (controls sleep/wake cycle/ breathing)
- medulla oblongata (myelencephalon)
what is the cerebellum responsible for
conscious/unconscious muscle movement; maintains balance and posture
damage to the cerebellum is characterized by ______ loss of balance and coordination
ipsilateral (same side)
what does the medulla oblongata control
-heart rate
-respiration
-blood pressure
-coughing
-sneezing
-swallowing
-vomiting
what are the sections of the spinal cord
- cervical (8)
- thoracic (12)
- lumbar (5)
- sacral (5)
- coccygeal (1)
what does the vertebral column contain
- 33 vertebrae (7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral, and 4 fused coccygeal)
- Intervertebral disks (absorbs shocks)
name the three portions of gray matter in the spinal cord
- posterior/dorsal horn
- lateral horn (neurons in autonomic nervous system)
- anterior/ventral horn
the posterior/dorsal horn of gray matter has sensory/_______ neurons, such as pain reception (stimulus to brain)
afferent
the anterior/ventral horn of gray matter has motor/_______ neurons (brain to muscle or gland responds/moves)
efferent
motor pathways of the upper motor neurons are found where
completely in the CNS
upper motor neurons control fine motor movement, destruction or injury of this can result in what
initial paralysis followed by partial recovery
cell bodies of lower motor neurons originate in the gray matter of the spinal cord and extend where
their axons extend into the PNS
lower motor neurons have a direct influence on muscles and destruction of these neurons can lead to what
permanent paralysis
______: protective structures that surround the brain and spinal cord
meninges
name the three components of the meninges
- dura mater (outer layer)
- arachnoid mater (middle layer)
- pia mater (inner layer)
the _____ mater is the periosteum of the skull and the inner dura or meningeal layer
dura
the ____ mater provides support and is filled with fluid to cushion structures
arachnoid
the ____ mater attaches to the brain and spinal cord
pia
the ____ space is located between the dura and arachnoid mater
subdural
the ___ space contains CSF and is located between the arachnoid and pia mater
subarachnoid mater
the ____ space is located between the dura mater and the skull
epidural
____ is a clear, colorless fluid similar to blood plasma and interstitial fluid
CSF
CSF and the ventricular system prevents the brain from doing what
tugging on the meninges, nerve roots, and blood vessels
CSF circulates btwn 125-150mL in the ventricles and is produced by the _________ in the lateral, third, and fourth ventricles
choroid plexus
CSF is reabsorbed through the _________
arachnoid villi
20% of blood flow is from the ____
heartbeat
____: provides collateral blood flow to the brian
arterial circle
what are the two divisions of the autonomic nervous system
sympathetic and parasympathetic
_____ neurons are unmyelinated and have slower conduction
postgangilonic
_______ neurons are myelinated and have faster conduction
preganglionic
stimulation of the sympathetic nervous system causes what (4)
- fight-or-flight
- decreased peristalsis
- increase in blood sugar, temp, BP
- regulates vasomotor tone
stimulation of the parasympathetic nervous system causes what (4)
- rest-and-secrete
- increase in digestion, salivation, urination
- controls pupil constriction and tear secretion
the sympathetic nervous system releases what two neurotransmitters
- epinephrine (central vasodilation)
- norepinephrine (peripheral vasoconstriction)
what neurotransmitters are released from sympathetic postganglionic fibers
norepinephrine/epinephrine
receptor of sympathetic postganglionic fibers
adrenergic (adrenaline)
neurotransmitters released from parasympathetic preganglionic and postganglionic fibers
acetylcholine
receptor of parasympathetic preganglionic and postganglionic fibers
cholinergic (muscarinic)