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Nervous System Adriana Bonilla Period 1 - Coggle Diagram
Nervous System Adriana Bonilla Period 1
Major functions
Controlling and communicating system of the body
Communication occurs through chemical and electrical signals instantaneously
3 overlapping functions
Integration:
Processing and interpretation of sensory input
Sensory input:
Information gathered by sensory receptors about internal and external changes
Motor output:
Activation of effector organs (muscles and glands) produces a response
Major divisions and subdivisions
Central Nervous system
Contains brain and spainal cord of dorsal body cavity
Integration and control center: receives sensory input and determines motor output
Peripheral Nervous System
Outside of the central nervous system. Mainly consists of nerves that extend from brain and spinal cord
Spinal nerves:
to and from spinal cord
Cranial nerves:
to and from brain
2 functional divisions:
Motor (efferent) division
transmits impulses from CNS to effector organs such as muscles and glands.
Somatic nervous system (voluntary):
Somatic motor nerve fibers conduct impulses from CNS to skeletal
muscle (conscious control of skeletal muscle)
Autonomic nervous system (involuntary): contains visceral motor nerves and regulates cardiac muscle, smooth muscle, and glands
Sympathetic division:
mobilizes body system during activity
parasympathetic division:
conserves energy
Sensory (afferent) division
Somatic sensory fibers
: convey impulses from skin, skeletal muscles, and joints
to CNS
Visceral sensory fibers:
convey impulses from visceral organs to CNS
tissues
Neuroglia (glial cells)
: small cells that surround and wrap delicate neurons
Astrocytes
: support and brace neurons, respond to nerve impule and neurotransmitters, involves information processing in brain, influence neauronal function. The most abundant and highly branched of all glial cells. Attaches to neurons, synaptic endings, capillaries
Microglial cells:
small cells with thorny processes that touch and monitor neurons. Migrates toward injured neurons
Oligodendrocytes:
Branched cells that Process wrap CNS nerve fibers, which form insulating myelin sheaths in thicker
nerve fibers
Ependymal cells:
Shape ranges from squamous to columnar. Line central cavities of brain and spinal column. Form permeable barrier between cerebrospinal fluid (CSF) in cavities and tissue
fluid bathing CNS cells
Neurons (nerve cells):
cells that transmit electrical signals
Cell body also know as perikaryon or soma
Nuclei:
clusters of neuron cell bodies in CNS
connective tissue coverings
Epineurium
: A tough fibrous sheath that Surrounds all fascicles and forms nerves with afferent and efferent fiber.
Endoneurium
: loose CT that encloses myelin sheaths (schwann cells) and axons
perineurium
: loose CT that bundles fibers into fascicles
classifications of neurons
Neuron:
transmits information to the brain using electrical or chemical impulses
Ganglia:
clusters of neuron cell bodies in PNS
Neuron processes:
Tracts:
Bundles of neuron cells in CNS
dendrites:
receptive region of a neuron. convey new messages to cell body as graded potentials (short distance signals). Collect information
Axons:
impulse generating and conducting region. Every neuron has an axon that starts at the axon hillock. Generates impulses and transmits message along axolemma to axon terminal
axon terminal:
region that secretes neurotransmitters, which get released into extracellular space
nerves:
bundles of neuron processes (2 types)
Nuclei:
clusters of neuron cell bodies in CNS
3 types based by number of processing
Multipolar:
3 or more processes.The mots common and major type in the CNS. (1 axon, other dendrites)
bipolar
: 2 processes. Rare to find (1 axon, 1 dendrite)
[unipolar]
:one T-like process. Also known as pseudounipolar (2 axons)
3 types based on direction that nerve impulse travels
Sensory:
Transmits impulses from sensory receptors toward CNS. Majority are unipolar. Cell bodies located in PNS ganglia
Motor:
Carry impulses from CNS to effectors. They are multipolar. Most are found in CNS except some autonomic neurons
interneuron:
Shuttle signals through CNS pathways. Also known as association neurons. 99% of the body's neurons are interneurons
Major parts and function of the spinal cord
Function: provides 2-way communication to and from brain to the rest of the body
Protected by bones, meninges and Cerebrospinal fluid (CSF)
Enclosed in vertebral column- Begins at the foramen magnum and ends at L1 or L2 Verterbra
Contains white matter: myelinated and nonmyelinated nerve fibers that allow communication between parts of spianl cord and brain
Contains Gray matter: crosss section that rezsembles butterfly or "H" there are 3 areas
Dorsal Horns:
inter-neurons that receive somatic and visceral visceral sensory input
ventral horns
: some interneurons:somatic neurons
lateral horns:
sympathetic neurons (only in thoracic and superior lumbar regions
cranial nerves
Olfactory nerves:
nerves that sense smell. Fibers synapse in olfactory bulb. Arise from retinas.
Optic Nerves
: Sensory visual function. Pass by optic canals, converge, , and slightly cross over at optic chiasma
Oculomotor nerves
: functions include, raising eyelid, constricting iris, controlling lens shape, and directing eyeball.
Trochlear nerves:
Extend from pons to face (largest of the cranial nerves). # divisions: Ophthalamic, maxillary, and mandibular. Convey sensory impulses from various areas of face
Abducens nerve:
Innervate lateral rectus muscle. fibers enter via superior orbital fissures
Facial Nerves
: allows for taste from anterior two-thirds tongue. The functions are facial expressions, and parasympathetic impulses to lacrimal
and salivary glands
Vestibulocochlear nerves:
Former auditory nerve. Afferent fibers from cochlear division and vestibular division pass from inner ear and enter brainstem.
Glossopharyngeal nerves:
: motor functions innervate tongue and pharynx when swallowing and provide parasympathetic fibers to parotid salivary glands. The sensory functions conduct taste
Vagus nerves::
The only nerves that pass head and neck region. most of the motor fibers are parasympathetic and help regulate activities of lung, heart and abdominal viscera
Accessory Nerves:
Former spinal accessory nerve. Innervates trapezius and
sternocleidomastoid muscles
Hypoglossal Nerves
: Innervate extrinsic and intrinsic muscles of tongue. Contributes to swallowing and speech abilities
Action potential and nerve impulse
Principle way that neurons transmit signals. Only occurs in muscle cells and axons of neurons
Order of signal: dendrites, axon, to myelin sheath, out the axon terminals
4 steps of action potential
Resting state: potassium and sodium channels are closed but leakage channels are open
Hyperpolarization: Some potassium channels stay open while all sodium channels reset. Membrane gets less negative
Depolraization state: Positive feedback from threshold causes all sodium channels to open up. Cell undergoes electrical shift
Repolarization: Potassium channels stay open while the sodium channels begin to inactivate. Membrane potential becomes negative potential
Major parts and functions of the brain
Functions:
controls thoughts, memory, vision, emotion, touch, temp, and motor skills
Lobes
Frontal:
controls behavior emotions, and speech. Also manages higher level of thinking and where you get you personality.
Parietal:
Sensory lobe of touch and pain. Contains somatosensory cortex which is responsible for detecting what we touch.
Temporal
: Responsible for processing and understanding auditory stimulus, memories, and some emotions.
Occipital
: Responsible for vision and some parts of taste and movement.
Cerebrum
: Regulates body temp., allows speech, thinking, personality, learning and emotions. Biggest part of brain
hypothalamus
Dura Mater:
Thalamus
Cerebellum:
Helps maintain balance within body as well as coordination. Influences good posture
Medulla Oblongata
: controls autonomic functions such as heart rate and and respiration
Pons
: relay sensory info and motor impulses to and from facial region to brain
spinal nerves
Supply all body parts except head and neck. There are 31 pairs of spinal nerves
8 pairs of cervical nerves (C1-C8)
Each spinal nerve is connected to spinal cord by 2 roots
Dorsal roots
: Contain sensory (afferent) fibers from sensory neurons in dorsal root ganglia
that conduct impulses from peripheral receptors
Ventral Roots:
Contain motor (efferent) fibers from ventral horn motor neurons that innervate
skeletal muscles
12 pairs of thoracic nerves (T1–T12)
5 pairs of lumbar nerves (L1–L5)
5 pairs of sacral nerves (S1–S5)
1 pair of tiny coccygeal nerves (C0)
Neurotransmitters
Chemical messengers in the body
Acetylcholine
Neurotransmitter at neuromuscular junction
located in PNS
contracts skeletal muscles and smooth muscles, activates glandular functions, slows heart rate, and can stimulate or block responses
Dopamine:
a pleasure chemical. plays role in human cognition and behavior. sends messages between nerve cells
glutamate
most excitatory neurotransmitter
involved in improving learning and memory
Serotonin
Calming chemical
helps manage appetite, memory, sleep, and decision making
Lack of serotonin can lead to depression
Norepinephrine
Also a horomone
connected to mood, arousal, stress, memory, and vigilance.
gamma-Aminobutyric acid (GABA)
inhobits neural signaling
plays role in brain development
too much can lead to seizures or other problems
Compare and contrast the autonmomic nervous system
Both the somatic and autonomic system have effectors, efferent pathways, and ganglia.
Autonomic Nervous System:
Function:
motor neurons innervate smooth muscle, cardiac muscle, and glands. Makes adjustments to support bofy for activities. Operates through subconscious control.
Effectors:
innervates cardiac. smooth muscle, and glands
efferent pathways and ganglia: uses 2-neuron chain
Preganglionic neuron:
cell body in CNS with preganglionic axon that extends to ganlion
Postganglionic neuron (not in CNS):
cell body synapses with preganglionic axon in autonomic ganglionic with nonmyelinated postganglionic axon that extends to effector organ
Somatic Nervous system
Effectors
: innervate skeletal muscles
Efferent pathways and ganglia
: cell body is in CNS, an axon extends in spinal cord or cranial nerve to skeletal muscle
Function
: voluntary control of skeletal muscles
Reflex arc
Describes the pathway the nerve impulse is carried asnd responded to with effector organs
somatic reflex:
activate skeletal muscle
Autonomic reflexes:
activate visceral effectors
Receptor detects stimulus 2. Sensory neuron sends afferent impulses to CNS 3. Integration Center: Either motorsynpatic or polysynaptic 4. Motor neuron conducts efferent impulses from integration center to effector organ 5. Muscle fibers or gland cells respond to efferent impulses by secreting or contracting
Disorder associated w/ Nervous System
Huntingtons disease
Herditary and fatal
Cause
: accumulation of Hannington in the brain cells. Both the cerebral cortex and basal nuclei degenerate
Symptoms: Mental state deteriates and flapping
Parkinsons disease
Dopamine releases and basal nuclei are overactive, Proteine digrade
Treatment: brain stimulation, L dopa, gene therapy
Alzheimer's:
Misfolded porteins cause dimentia
Symptoms:
short attention span, memory loss, confusion, moodiness, hallucinations, and language deteriorates
Treatment
: no cures exist but some medications can improve symptoms
Drugs
Cocaine: Causes an energetic and alert feeling.
Meth:
Dopamine neurotransmitter is replaced with meth and enters the synapse. The dopamine overstimulates the cell. After taking meth you will get a sense of intense pleasure which causes addiction
LSD:
Effects serotonin effectors. Causes a you to be very responsive as well as alter someone's mid. Hallucinations
Ecstasy:
Effects serotonin neurotransmitters. Acts as serotonin and when the limit is exceeded serotonin leaves the cell causing a feeling of confusion and anxiety, while also increasing your heart rate
Marijuana:
Effects terminals in the brain and cause a relaxed and calm feeling. The drug is used to relieve stress and anxiety
Alcohol
: Effects glutamate neurotransmitter and Gaba neurotransmitter in the brain. Prevents glutamate from leaving cell.
Heroine:
Effects inhibitory transmitters. This turns off dopamine inhibitation. Heroine causes you to feel relaxed and detached.