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Jenesis Perez Per.2 Nervous System - Coggle Diagram
Jenesis Perez Per.2 Nervous System
Major parts and functions of the brain
Cerebellum
coordinates muscular activity
Diencephalon
hypothalamus and thalamus
processes sensory input
Surrounds the third ventricle
Cerebrum
Frontal lobe
higher mental functions,
sensory & motor functions
Occipital lobes
Temporal lobe
Parietal lobe
Brainstem
coordinates and regulates visceral activities
pons
Medulla oblongata
midbrain
Major Function
Movement
Sensory
sensory receptors
detects internal and external changes
information travels through receptors to sensory neurons to transport information to the CNS
Thinking
integration
coordination and processing
Processing information is the basis for decision-making
Motor function
response
Nerve impulses in CNS are conducted along motor neurons to the effectors
Effectors are muscles or glands that respond to decisions that are made in the CNS
Classification of Neuron
Multipolar neurons
many dendrites and one axon
interneurons
and motor neurons
Bipolar neurons
2 processes extending from the cell body, a
dendrite and an axon
Unipolar neurons
only 1 process extending
splits into 2 parts that function as 1
axon
sensory neurons
Motor neurons
multipolar neurons
conduct
impulses from the CNS to peripheral effectors
muscles or glands
Sensory neuron
conduct impulses from peripheral
receptors to the CNS
usually is unipolar but some are bipolar.
Interneurons
multipolar neurons lying within the CNS
Nuclei: aggregate in specialized masses
Major parts and functions of the spinal cord
base of the brain
Cauda equina
spinal cord tapers
spinal nerves in the lumbar & sacral areas
31 segments
Lumbar enlargement
thickened region near the bottom
rise to nerves that serve the lower limbs
Cervical enlargement
thickened area near top
nerves to upper limbs
transmit impulses to and from the brain
dorsal
root ganglia
lateral horn is between the upper and lower wings of gray matter from anterior and posterior
central canal
middle of the gray matter contains cerebrospinal fluid
Structure & Function of neurons and neuroglia
Neurons
cells that communicate, (electrical impulses) with
other neurons or other tissues
Structure
cell body, tubular cytoplasm-filled dendrites, and a
tubular, cytoplasm-filled axon
axon conducts impulses away from the cell body
thick extending from the cell body
axon hillock
only 1 axon in each neuron
Dendrites conduct impulses toward the cell body
Short
branching
have a receptive surface to communicate with other neurons
A cell body or soma contains the major organelles like the nucleus
nodes of Ranvier
Narrow gaps in the myelin sheath
Myelin Sheath
increases conduction speed of nerve impulses
myelinated fibers
Larger axons are enclosed by myelin sheaths
Neuroglia
cells that support, nourish, protect, and insulate
neurons
support neurons
PNS: 2 types
CNS: 4 types
Do not generate or conduct nerve impulses
Microglia
produce scar tissue
Ependymal cells
produce cerebrospinal fluid in CNS
Oligodendrocytes
form the myelin sheath around axons in the brain
and spinal cord
Astrocytes
are between blood vessels and neurons
structural support
blood-brain barrier
protects brain
tissue
Connective Tissue Coverings
Epineurium
outer coverings of a nerve
Endoneurium
covering around individual nerve fibers
Perineurium
covering around fascicles
Major Division
Subdivisions
CNS
Responsible for integration of information and decision-making
Brain and spinal cord
PNS
cranial and spinal nerves that connect the CNS
Autonomic nervous system
controls voluntary skeletal muscles
smooth and
cardiac muscles and glands
it connects the CNS to viscera, and
controls subconscious activities
Somatic nervous system
controls involuntary effectors
it connects the CNS to skeletal muscles and
the skin, and oversees conscious activities
has cranial nerves, arising from the brain, and spinal
nerves, arising from the spinal cord.
sensory and motor divisions
Action potential & the Nerve Impulse
Nerve Impulse
Saltatory conduction
Happens in myelinated axons
myelin sheath insulates axons from ion movement
Impulses jump from one Node of Ranvier to the next one
Continuous conduction
Happens in unmyelinated axons
Conduct impulses sequentially over entire length
An action potential at trigger zone causes electrical current flow to adjacent regions of the axon’s membrane
Action potential
all-or-none response
occurs when the charge reaches -55 mV
occurs or does not
neuron are all of the same strength
When it's reached cell goes to resting potential by repolarization
overshoot is called hyperpolarization
Cranial nerves
underside of the
brain
Most are mixed nerves
Twelve pairs of cranial nerves
I Olfactory: (Type Sensory) Sensory fibers conduct impulses associated with the sense of smell
VIII Vestibulocochlear: (sensory) Vestibular branch and Cochlear branch
VII Facial: (mixed)
Sensory fibers conduct impulses associated with taste receptors of the anterior tongue.
Motor
fibers conduct impulses to muscles of facial expression, tear glands, and salivary glands
IX Glossopharyngeal: (mixed)
from the pharynx, tonsils, posterior tongue, and carotid
arteries
Motor fibers conduct impulses to muscles of the pharynx used in swallowing and to salivary
glands
VI Abducens: (primarily motor)
Motor fibers conduct impulses to muscles that move the eyes
the condition of muscles
X Vagus: (mixed)
Somatic motor fibers conduct impulses to muscles associated with speech and swallowing
Sensory fibers conduct impulses from the pharynx, larynx, esophagus, and viscera of the thorax
and abdomen.
V Trigeminal : (mixed) Ophthalmic division, Maxillary division and Mandibular division
XI Accessory: (primarily motor) cranial and spinal branch
IV Trochlear: (Primarily motor)Motor fibers conduct impulses to muscles that move the eyes
XII Hypoglossal: (primarily motor) Motor fibers conduct impulses to muscles that move the tongue.
III Oculomotor: (Type primarily motor) Motor fibers conduct impulses to muscles that raise eyelids, move eyes, adjust the amount of light entering the eyes, and focus lenses
II Optic: (Type Sensory) Sensory fibers conduct impulses associated with the sense of vision
first pair arises from the cerebrum
most arise from the brainstem
second pair from
the thalamus
Spinal nerves
All except the first pair are mixed nerves
31 pairs of spinal nerves
Brachial Plexuses (C5 –T1)
Lower cervical and upper thoracic
nerves
supply muscles and skin of arms
Musculocutaneous, ulnar, median, radial, and
axillary nerves
Lumbosacral Plexuses (L1-S4)
lower spinal cord
supply
muscles and skin of the lower abdomen
Cervical Plexuses (C1-C4)
side of the neck
Supply muscles and
skin of the neck
control the diaphragm
intercostal nerves (T1-T11)
Anterior branches of the thoracic spinal nerves do not form plexuses
Neurotransmitters
The chemical messengers in a synapse, that
convey an electrical impulse from a neuron to another cell
more than 100 neurotransmitters
norepinephrine
CNS
Creates a sense of feeling good
PNS
May excite or inhibit autonomic nervous system actions
epinephrine
hormone
acetylcholine
PNS
Stimulates skeletal muscle contraction at neuromuscular junctions
CNS
Controls skeletal muscle actions
acetylcholine, amino acids,
neuropeptides
Compare & contrast the autonomic nervous system
Somatic nervous system
connects the CNS to skeletal muscles and
the skin
conscious activities
Autonomic nervous system
connects the CNS to viscera
controls subconscious activities
Reflex arc
sensory receptor
detects changes
sensory neuron
carries the information from a receptor
toward the CNS
involuntary actions called reflexes
interneuron
reflex center
dendrite, cell body and axon, which is found in the brain or spinal cord
motor neuron
carries a command to effectors
effector
responds
to the initial change
Muscle or gland
receptor -> sensory neuron -> CNS -> motor neuron -> effector