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Nervous System Linh Le Period 1 - Coggle Diagram
Nervous System Linh Le Period 1
Major functions of the nervous system:
It is the communication system of the body, using electrical and chemical signals.
Integration: the processing and interpreting of sensory input
Motor Output: triggering of the effector organs which produce a response to the sensory input
Sensory Input: information gathered by sensory receptors about internal/external changes
Action potential & the Nerve Impulse:
Resting Membrane Potential: -70 mV
Sodium-potassium pump (Na+ & K+) stabilizes resting membrane potential- maintaining concentration gradient
Graded potentials: short distance
Action Potential:
Resting state: gated Na+ and K+ channels are closed
Depolarization: Na+ channels open- when Na+ rushes in more gates open; results in spike in action potential
Repolarization: Na+ channels inactivate and declines to resting state, K+ channels open,
Hyperpolarization: Some K+ channels reopen, Na+ channels reset- inside of membrane becomes more negative
Refractory period: time after action potential where neuron cannot trigger another one
Conduction Velocity: AP occurs only in axon
Continuous conduction: slow conduction in unmyelinated axons
Saltatory conduction: only occurs in myelinated axons and is 30x faster
Drugs:
Alcohol: makes GABA receptors more inhibitory; causes person to have memory loss and impulsive
Marijuana: mimics anandamine; person will feel relaxed and calm
Methamphetamine: mimics dopamine; causes person to feel intense pleasure
LSD: mimics serotonin; causes person react very spontaneously to stimulus
Cocaine: blocks dopamine transporters; causes person to be fidgety
Ecstasy: mimics serotonin; person will feel calmed but quickly addicted
Heroin: mimics body's opioid; causes person to feel sedated
Major parts and functions of the spinal cord:
The spinal cord provides a two-way communication from brain to body and is the major reflex center
Structure of the Spinal Cord:
Ventral median fissure
Dorsal median fissure
Gray matter
Dorsal horns: interneurons receive sensory input
Ventral horns: some interneurons; somatic motor neurons
Lateral horns: sympathettic neurons
Grey commissure: bridge of grey matter connecting both halves
Ventral roots: bundle of motor neuron axons
Dorsal roots: sensory input to cord
Major parts and functions of the brain:
Cerebral Hemispheres:
Left- controls language, math & logic
Right- controls visual-spatial skills, intuition, emotion & creativity
Parietal lobe: controls sensory perception and integration of the five senses (sight, smell, touch, taste, sound)
Occipital lobe: the visual cortex
Frontal lobe: controls voluntary movement and higher mental functions such as memory, consciousness, thinking, language, problem-solving, etc
Temporal lobe: the auditory cortex
Diencephalon:
Thalamus: relay station for sensory input
Hypothalamus: main visceral control & regulating center vital to homeostasis
Epithalamus: contains pineal gland that secretes hormone melatonin
Brainstem: controls automatic functions necessary for survival
Midbrain: between diencephalon & pons
Pons: between midbrain & medulla
Medulla oblongata: lowest part of brainstem; regulates respiratory & cardiovascular centers
Sulci & Fissures (grooves):
Transverse cerebral fissure: separates cerebrum & cerebellum
Central sulcus: separates precentral & postcentral gyri in parietal lobe (located in middle of cerebrum)
Longitudinal fissure: separates hemispheres
Parieto-occipital sulcus: separates occipital & parietal lobes
Lateral sulcus: outlines temporal lobes
Cortexes:
Primary motor cortex: voluntary movement
Premotor cortex: plans movement
Broca's area: produces speech
Wernicke's area: understands speech
Primary somatosensory cortex: receives general sensory input
Somatosensory association cortex: integrates sensory input for understanding
Multimodal association areas; give meaning to info, store into memory, & associate with previous experiences
Cerebellum: processes info from cerebrum, brainstem & sensory receptors to coordinate skeletal muscles; balance and coordination
Reticular formation: maintains cerebral cortical alertness; filters out repetitive stimuli; helps regulate skeletal and visceral muscle activity
Limbic system: the affective brain; regulates emotions which output is relayed by hypothalamus
Meninges: protective membranes that separate the brain and the skull
Dura mater: the toughest and outermost covering
Arachnoid mater: web-like membrane between dura and pia
Pia mater: thin delicate membrane that is deepest of meninges
Ventricles: cerebrospinal fluid filled spaces in the brain
Lateral ventricles: C-shaped chambers located in each hempisphere
3rd ventricle: connected to lateral ventricles
4th ventricle: connected to 3rd ventricle by cerebral aqueduct
Connective Tissue Coverings:
Epineurium: Outermost covering of a nerve
Perineurium: Sheaths nerve fasicles
Endoneurium: Encloses individual nerve fibers
Neurotransmitters: the language of the nervous system
Amino acids: make up all protein
Acetylcholine: allows for muscle contraction
Endorphins: natural opiates; pain relief
Compare & contrast the autonomic nervous system:
Parasympathetic:
long preganglionic and short postganglionic fibers
few branches on axons
located in visceral effectors
Sympathetic:
short preganglionic and long postganglionic fibers
highly branched axons
located near spinal cord
Reflex arc (major parts & functions):
A rapid involuntary motor response to stimulus which
Sensory neuron: transmits afferent impulses -> CNS
Integration center: either monosynaptic or polysynaptic region
Receptor: site of stimulus action
Motor neuron: conducts efferent impulses from integration center -> effector organ
Effector: muscle fiber/gland cell that responds to efferent impulses by contracting/secreting
Tissues (structure & function of neurons and neuroglia):
White matter: myelinated tissue that communicates between cortex, lower CNS, & cerebral areas
Grey matter: nonmyelinated
Neuron: excitable cells that transmit electrical signals
Soma: neural cell body containing nucleus
Dendrites: short, tapering branched that convey messages to cell body (receives)
Axon: nerve fiber; generates nerve impulses to excite neurons it contacts
Myelin sheath: fatty tissue that insulates axon and speeds up nerve impulse
Neuroglia: cells that protect and maintain neurons
Astrocytes: most abundant and versatile; supports neurons
Microglial cells: migrate to injured neurons
Ependymial cells: line central cavities of cerebrospinal column
Oligodendrites: cells that wrap nerve fibers, forms myelin sheaths
Satellite cells: surround neuron cell bodies in PNS
Schwann cells: form myelin sheath in PNS
Major divisions and subdivisions of the nervous system:
Central Nervous System: the brain & spinal cord
Peripheral Nervous System: nerves connecting the CNS to environment
Sensory
Motor
Somatic: the body's movement system (voluntary control)
Autonomic: responsible for regulating body's processes (nonvoluntary)
Sympathetic Nervous System: creates a response to adjust the body to the environment ("fight or flight")
Parasympathetic Nervous System: conserves the body's energy after emergency response occurs ("rest and digest")
Disorders associated with Nervous System:
Alzheimer's: results in dementia; brain shrinks causing memory loss, hallucinations, disorientation
Parkinson's: degeneration of dopamine causing tremors at rest
Huntington's: influx of protein causes mental deterioration
Amytrophic lateral sclerosis: destruction of ventral horn roots, resulting in loss of ability to speak, breathe, swallow
Cranial nerves:
V: Trigeminal Nerve
sensory impulses from various areas of face, motor fiber for mastication (chewing)
VI: Abducens
primary motor nerve innervating lateral rectus muscle (eyeball)
IV: Trochlear
innervates superior oblique; primary motor nerve that directs eyeball
VII: Facial Nerve
chief motor nerves of face for facial expression, parasympathetic impulses to lacrimal and salivary glands; sensory function (taste)
III: Oculomotor
raise eye lids, pupillary constriction, change lens shape
VIII: Vestibulocochlear
hearing and balance; auditory nerve, purely sensory
IX: Vestibulocochlear
motor- depress tongue, and pharynx for swallowing
sensory- conduct taste, general sensory impulses from pharynx
II: Optic
vision, purely sensory
X: Vagus Nerve
motor- regulate activities of heart, lungs and abdominal viscera
sensory- carry impulse from thoracic & abdominal viscera, baroreceptors, chemoreceptors and taste buds of tongue and pharynx
I: Olfactory
smell, purely sensory
XI: Accessory Nerve
innervates trapezius and sternocleidomastoid
XII: Hypooglossal Nerve
innervate extrinsic and intrinsic muscles of tongue (swallowing & speech)
Spinal nerves (31 pairs): formed by fusion of dorsal and ventral roots
8 pairs of cervical nerve (C1-C8)
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 (C0)
Classification of neurons:
Bipolar: two processes (1 axon 1 dendrite)
Unipolar: one T-like process (2 axons)
Multipolar: three or more processes
Sensory: transmit impulses from sensory receptors to CNS
Motor: carry impulses from CNS to effectors
Interneurons: between sensory & motor neurons & shuttles signals through CNS pathways