nervous system Flashcards
receiving sensory input, integrating information, controlling muscles and glands, maintaining homeostasis, and serving as the center of mental activity.
nervous system
-consists of the brain and spinal cord
-constantly receives sensory input.
central nervous system
-consists of all the nervous tissue outside the CNS.
-transmits action potentials to the CNS; the motor division carries action potentials away from the CNS.
peripheral nervous system
divided into somatic and autonomic systems.
motor division
innervates skeletal muscle and is mostly under voluntary control.
somatic motor system
-innervates skeletal muscle and is mostly under voluntary control.
-divided into sympathetic and parasympathetic divisions.
autonomic nervous system
contains both sensory and motor neurons, which can function independently of the CNS.
enteric nervous system
-receive stimuli and conduct action potentials.
-consists of a cell body, dendrites, and an axon.
-multipolar, bipolar, or pseudo-unipolar.
neurons
the support cells of the nervous system. They include astrocytes, ependymal cells, microglia, oligodendrocytes, and Schwann cells.
glial cells
either unmyelinated or myelinated.
axons
consists of white matter and gray matter.
nervous tissue
forms the cortex and nuclei in the brain and ganglia in the PNS.
gray matter
forms nerve tracts in the CNS and nerves in the PNS.
white matter
-results from the charge difference across the membrane of cells.
-set by leak ion channels and the sodium-potassium pump.
resting membrane potential
occurs when the charge across the cell membrane is briefly reversed.
action potential
generate the action potential.
Chemically gated and voltage-gated ion channels
occurs along unmyelinated axons.
continuous conduction
occurs along myelinated axons.
saltatory conduction
point of contact between two neurons or between a neuron and another cell, such as a muscle or gland cell.
synapse
are either converging or diverging.
neuronal pathways
occur in neuronal pathways.
spatial and temporal summation
xtends from the foramen magnum to the second lumbar vertebra; below that is the cauda equina.
spinal cord
has a central gray part organized into horn
spinal cord
part forming nerve tracts.
peripheral white
extend out of the cord
roots of spinal nerves
the functional units of the nervous system.
reflex arcs
consists of a sensory receptor, a sensory neuron, interneurons, a motor neuron, and an effector organ; the simplest reflex arcs do not involve interneurons.
complex reflex arc
occurs when the quadriceps femoris muscle is stretched.
knee jerk reflex
removes a body part from a painful stimulus.
withdrawal reflex
exit the vertebral column at the cervical, thoracic, lumbar, and sacral regions.
spinal nerves
are grouped into plexuses.
nerves
which supplies the diaphragm, is the most important branch of the cervical plexus.
phrenic nerve
supplies nerves to the upper limb.
brachial plexus
supplies nerves to the lower limb
lumbosacral plexus
contains several nuclei.
brainstem
contains nuclei that control activities such as heart rate, breathing, swallowing, and balance.
medulla oblongata
contains relay nuclei between the cerebrum and cerebellum.
pons
involved in hearing and in visual reflexes.
midbrain
scattered throughout the brainstem and is important in regulating cyclical motor functions. It is also involved in maintaining consciousness and in the sleep-wake cycle.
reticular formation
attached to the brainstem.
cerebellum
consists of the thalamus (main sensory relay center)
diencephalon
the pineal gland may play a role in sexual maturation
epithalamus
important in maintaining homeostasis
hypothalamus
has two hemispheres, each divided into lobes: the frontal, parietal, occipital, and temporal lobes.
cerebrum
-transmit action potentials from the periphery to the brain.
-project to primary sensory areas of the cerebral cortex.
ascending tracts
involved in recognizing the sensory input.
association areas
functions include involuntary and voluntary movements.
somatic motor
-the cerebral cortex connect to lower motor neurons in the spinal cord or cranial nerve nuclei.
-located in the primary motor cortex.
upper motor neurons
regulate movements.
premotor and prefrontal areas
project directly from upper motor neurons in the cerebral cortex to lower motor neurons in the spinal cord
descending tract
indirectly, they project from basal nuclei
brainstem
through the brainstem to lower motor neurons in the spinal cord.
cerebellum or cerebral cortex
help plan, organize, and coordinate motor movements and posture.
basal nuclei
-involved in balance, muscle tone, and muscle coordination.
-compares the intended action to what is occurring and modifies the action to eliminate differences.
-damaged, muscle tone decreases and fine motor movements become very clumsy.
cerebellum
controls the opposite half of the body.
hemisphere
connect the two hemispheres.
commissures
thought to be the dominant analytical hemisphere
left hemisphere
thought to be dominant for spatial perception and musical ability.
right hemisphere
involves the sensory speech area, the motor speech area, and the interactions between them and other cortical areas.
speech
brain waves, which are a summation of the electrical activity of the brain.
EEG monitors
lasting a few seconds to minutes
working
lasting a few minutes
short term
-permanent memory.
-includes declarative and procedural memories.
long term
-includes the olfactory cortex, deep cortical regions, and nuclei.
-involved with memory, motivation, mood, and other visceral functions. Olfactory stimulation is a major influence.
limbic system
contain fluid-filled cavities:
brain and spinal cord
in the cerebral hemispheres,
lateral ventricles
in the diencephalon,
third ventricle
in the midbrain
cerebral aqueduct
-at the base of the cerebellum, and a central canal in the spinal cord.
-has openings into the subarachnoid space.
fourth ventricle
formed in the choroid plexuses in the ventricles. It exits through the fourth ventricle and reenters the blood through arachnoid granulations in the superior sagittal sinus.
cerebrospinal fluid
how many airs of cranial nerves
12 pairs
how many are the sensory function (S)
3
how many are the somatic motor function (M)
4
how many is the somatic motor (M) and sensory function (S),
1
how many are the somatic motor and parasympathetic (P) function, 3 with all three functions.
1
how many are the of the cranial nerves have parasympathetic function.
4
-contains preganglionic and postganglionic neurons.
-has sympathetic and parasympathetic divisions.
autonomic nervous system
-the sympathetic division lie in the thoracic and upper lumbar regions of the spinal cord.
- parasympathetic division are associated with some of the cranial and sacral nerves.
preganglionic cell bodies
-located in the sympathetic chain ganglia or in collateral ganglia.
-located in terminal ganglia, either near or within target organs.
postganglionic cell bodies
All autonomic preganglionic and parasympathetic postganglionic neurons is
secrete acetylcholine
Most sympathetic postganglionic neurons is
secrete norepinephrine
prepares a person for action by increasing heart rate, blood pressure, respiration, and release of glucose for energy.
symphathetic division
involved in involuntary activities at rest, such as the digestion of food, defecation, and urination.
parasympathetic division
-forms plexuses in the digestive tract wall.
-are sensory, motor, or interneurons; they receive CNS input but can also function independently.
enteric nervous system
