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53 Cards in this Set
- Front
- Back
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Neuro system
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Nervous system-
Responsible for interacting with the environment Coordinate and organize functions of all body parts Transmit electrical & chemical signals between body organs & tissues and the brain |
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Divisions CNS and PNS
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CNS is divided into Central Nervous System & Peripheral Nervous System
CNS- brain & spinal cord PNS- cranial nerves & spinal nerves |
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Peripheral nervous system (PNS)
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-Somatic nervous system- motor & sensory pathways regulating motor control of skeletal muscle
-Autonomic nervous system – regulation of body’s internal env- ( viscera) thru involuntary control of organ system |
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Autonomic nervous system (ANS)
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ANS is further divided into:
-Sympathetic Division -Parasympathetic Division |
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ANS function
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regulates activities of internal organs and to maintain and restore internal homeostasis
-Sympathetic NS “Fight or flight” responses Main neurotransmitter is norepinephrine -Parasympathetic NS Controls mostly visceral functions Regulated by centers in the spinal cord, brainstem, and hypothalamus |
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CNS
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Compose of :
Brain Spinal Cord Major functional divisions Higher level brain- or cerebral cortex (neocortex) Lower level brain– basal ganglia, thalamus, hypothalamus, midbrain, pons, medulla, cerebellum Spinal Cord |
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Brain: Cerebrum
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Divided into cerebral hemispheres
Cerebral cortex (neocortex) Frontal lobe- motor Parietal lobe: tactile Occipital lobe: vision Temporal lobe: auditory Central lobe: taste |
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Right Cerebral hemisphere
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Superior at simultaneous processing such as required for spatial-visual tasks
Vital for non language sounds such as music, of visual experiences, and of spatial relationships Memories are stored in a holistic fashion as the auditory, visual and spatial stimuli are experienced Orchestrates holistic performance such as athletic or ballet performance |
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Left Cerebral hemisphere
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Superior ability for tasks requiring an orderly, logical and systematic assessment of components of language, mathematical calculations, complex abstraction, and reasoning
Analytical mode using sequential analysis Memories are thought to be stored as the component parts and in language format |
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Frontal lobe
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Frontal lobe- precentral gyrus( motor cortex)- regulates voluntary movements. Generally, fibers cross to the opposite side of the brain at the medulla and descend via the spinal cord as the lateral corticospinal tracts i.e. contralateral
Precentral gyrus ( premotor area) –coordinates muscular activity of mouth, tongue & larynx when speaking. Broca’s aphasia- damage to this area ( usually in the left hemisphere) . Pt is unable to express self clearly . Prefrontal area- - control attention over time. Motivation, ability to formulate goals, plan, - executive function - |
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Parietal
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Involve in sensory association- storage, analysis & interpretations of stimuli
Temperature, touch, pressure Awareness of size & shapes- stereognosis Awareness of position- proprioception Awareness of body parts,visual spatial information & controls spatial orientation Occipital lobe- receives input from the retinas; involve in visual association Temporal lobe– primary auditory receptive areas. Secondary function- balance, taste, & smell (Visual , auditory & olfactory perception ) Wernicke area _ ( speech area) located in temporal lobe Damage – lead to inability to understand spoken or written language; music or env noise. i.e, -receptive aphasia Central lobe- nerve fibers for taste pass thru this lobe |
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Brain : Hippocampus
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Part of the middle section of temporal lobe.
Memory function Short term memory- lost after sec or mins Intermediate memory-last days to weeks Long term –(remote) memory- stored & last for a long time |
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Brain: Basal Ganglia
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Consists of :
Subcortical gray matter Internal capsule Exert a fine tuning effect on motor movements. Parkinson & Huntington diseases are associated with defects of basal ganglia |
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Diencephalon
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Diencephalon-
Thalamus – relay center for sensory info except smell Hypothalamus- regulates ANS- T, HR, BP. F/E . GI |
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Hypothalamus
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Visceral & somatic responses
Affectual responses Hormone synthesis Sympathetic & parasympathetic activity Temperature regulation Feeding responses Physical expression of emotions Sexual behavior Pleasure –punishment centers Level of arousal or wakefulness |
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Limbic syst
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Limbic system-
Centers of feeling & emotional expression |
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Brain stem
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Brain Stem -
Midbrain, pons, & medulla oblongata |
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Reticular formation
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Reticular formation-
Skeletal motor function Reticular activating system – control sleep wake cycle & consciousness |
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Cerebellum
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The anterior lobe regulates postural reflexes.
The posterior lobe controls coordination of voluntary muscle activity and muscle tone. Coordinates location in space and movements All sensory modalities are circuited through which provides information about muscle activity It controls fine movement, coordinates muscle groups, and maintains balance *Generally, nerve tracts travel through various nuclei without crossing ---- right cerebellar hemishere affects the right ( ipsilateral) side of the body & vice versa |
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Spinal cord
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Portion of the CNS that lies within the vertebral canal & is surrounded & protected by the vertebral column
Long cable that connects brain & body Conduct somatic & autonomic reflexes Provide motor pattern control centers Serve as a sensory & motor modulation center **Protective & nutritional structures: Cranium & Vertebral column Meninges Cerebrospinal Fluid & Ventricular System Blood brain barrier Arterial blood supply Venous supply |
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Pathways
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Ascending sensory pathways- carry sensory information through the spinal cord to the brain
Descending ( motor) pathways- efferent signals to the spinal cord |
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Spinal Cord Sections
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7 cervical vertebrae
12 thoracic vertebrae 5 lumbar vertebrae 5 sacral vertebrae 4 coccygeal vertebrae- fused into coccyx |
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PROTECTION FOR CNS
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Bone- vertebrae surround cord: skull surrounds the brain
Meninges:three connective tissue membranes that cover the brain and spinal cord Dura mater: outer most & most fibrous fibrous tissue: Arachnoid: delicate membranes: middle layer : Space between pia & arachnoid is subarachnoid space & CSF flows thru this Pia mater: inner layer covering brain & spinal cord; carries rich supply of blood vessels |
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spaces
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Epidural between dura mater and the vertebrae. Used for administering medications
Subdural space: between dura mater and arachnoid Subarchnoid space: between arachnoid and pia mater, contains cerebrospinal fluid. Used for dx. test |
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Cerebrospinal Fluid
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acts as a shock absorber: acts in exchange of nutrients and waste materials
Cerebrospinal Fluid Clear & colorless fluid Produced in ventricles & circulated around brain & spinal cord by ventricular system. CSF produced in choroid plexus of the 4 lateral ventricles lateral, 3th & 4th ventricles. Organic & inorganic contents of CSF similar to plasma, but their concentration is different. CSF analyzed for protein, glucose, & chloride on routine analysis; may also be tested for immunoglobulins. CSF has minimal #WBCs and no RBCs |
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Reflex Mechanisms
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Involuntary movements in response to external & internal stimuli.
Example: Extension and flexion Knee jerk reflex Withdrawal reflex |
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Function of CSF
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-surrounds & cushions the brain & spinal cord. Action: Circulates thru subarchnoid space,continuously reabsorbed by arachnoid villi & then channeled into superior sagittal sinus. Spinothalamic tracts being in the spinal cord & end in the thalamus
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Blood Brain Barrier-maintain stable environment for neurons
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Three barriers- bld –brain. bld –CSF, brain -CSF
Formed by endothelial cells of brain capillaries, continuous tight junction creating low and selective permeability. Barrier to macromolecules. All substances entering CSF must filter thru choroid plexus. May be altered by trauma, cerebral edema, cerebral hypoxemia |
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Blood supply
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Brain receives approx 15 % of CO or 750 – of bld/min
CO2- primary regulator for bld flow w/in the CNS. It is potent vasodilator in the CNS, and its effect ensure an adequate bld supply Arterial supply- Vertebral artery system- supply brain stem, cerebellum - |
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Venous supply
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Most of the venous bld from the head returns to the heart through the internal jugular veins, the external jugular veins & vertebral veins.
( Adequacy of venous outflow can have a significant effect on intracranial pressure. Individuals with head injury, turning or letting the head fall to side partially occludes venous return & can increase pressure because of decreased flow through the jugular vein |
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Cells of the Nervous System
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Neurons- primary cell of the nervous system
Integrate many systems at higher cognitive levels & initiate responses to maintain homeostasis Responsible for communication Neuroglia- ( “ nerve glue”)- comprise the general classification of cells that support the neurons of the CNS |
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Neuroglia
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4 types:
Astrocytes- supply nutrients Oligodendrocytes- similar to Schwann cells Microglia– removes debris in the CNS (phagocytosis) Ependymal-- lines the central canal of spinal cord & brain |
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structure & physiology
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Neurons or nerve cells
Respond to a stimulus, connect it into a nerve impulse (irritability), and transmit the impulse to neurons, muscle, or glands (conductivity) Each neuron consists of three main parts (1) Cell Body (2) Dendrites (3) Axons Each dendrite synapses with another cell body, axon or dendrite Axons are covered by myelin sheath |
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Neuron main parts
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Cell body ( soma): contains nucleus and one or more fibers or process extending from cell body
Dendrites: conduct impulses toward cell body: neurons has many dendrites Axons: conduct impulses away from cell body: neuron has one axon |
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Types of neurons
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Unipolar-
Multipolar Bipolar |
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Synapses
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Synapse- region between adjacent neurons. Impulses are transmitted across the synapse by chemical and electrical conduction
Presynaptic – neurons that relay impulses toward the synapse Postsynaptic- neurons that relay impulses away from the synapse |
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neurotransmitters
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Communicate messages from one neuron to another or to a specific target tissue.
Neurotransmitters can potentiate, terminate, or modulate a specific action or can excite or inhibit a target cell. Many neurologic disorders are due to imbalance in neurotransmitters. Neurotransmitters-conducting substance formed at the synaptic boutons of the presynaptic neurons axon & stored in synaptic vesicles More than 100 neurotransmitter have been identified: e.g.: Norepinephrine, acetylcholine, dopamine, histamine,y aminobutyric acid (GABA). serotonin |
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Impulse Conduction
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Resting potential- not conducting an impulse
Nerve impulse- Myelin- Receptors- |
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structure & physiology
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Synapse-small spaces between neurons & their target;
Myelin sheath – protects and insulates the axon fibers: increases the rate of transmission of nerve impulses Neurilemma– sheath covering the myelin: found in PNS : function is regeneration of nerve fiber |
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Transmission & Transmitters
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Transmission can be affected by:
(1) Strength of the stimulus (2) Inadequate supply of substance (3) Cerebrospinal Fluid changes (CSF) (4) Lack of oxygen (5) Acidosis or Alkalosis (6) Drugs |
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Electolytes for Nerve Impulse Conduction
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Primary mechanism for nerve impulse conductions are Na and Chloride ions Heavy concentration in extracellular
K = intracellular concentration Na & Cl outside cell K inside cell Varying concentrations causes a neuron to always be charged. Depolarization caused by stimulus causing polarity changes causes depolarization. Repolarization Na in cell, K outside cell, then repolarization with Na being actively pumped back out. Protein allow access to either K or Na but not both |
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Gray matter
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Gray matter- clusters of neuron cell bodies—fibers not covered with myelin –distributes impulses across selected synapses
Unmyelinated: Impulses are slower. Make up Gray matter of CNS |
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white matter etc
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Ganglia-clusters of nerve cells outside CNS
White Matter-bundles of myelin nerve fibers – conducts impulses along fibers. Myelinated: covered with white lipid/protein material which insulates the axonal membrane, >speed of electrical conduction down membrane. Myelin sheath are segmented. Nodes of Ranvier- Spaces between segments- purpose to facilitate rapid impulse transmission. Myelinated fibers make up white matter of CNS |
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PNS
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PNS –includes cranial & spinal nerves including their branches & ganglia
Peripheral nerve is composed of individual axons, dendrites mostly wrapped in myelin sheath |
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PNS
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Types of neurons
Motor (efferent ): conduct impulses away from the brain & spinal cord (CNS) to muscle and glands Sensory (afferent): conduct impulses toward CNS- brain & spinal cord Connecting (interneuron): Conduct impulses from axon to dendrites |
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PNS
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Spinal Nerves
Dorsal ( sensory ) roots Ventral ( ventral ) roots Cranial Nerves 12 pairs motor/sensory |
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spinal nerves
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31 pairs of spinal nerves
8 pairs of cervical nerves 12 pairs of thoracic nerves 5 pairs of lumbar nerves 5 pairs of sacral nerves 1 coccygeal nerves |
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Major plexuses-
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Cervical plexus- supplies the muscles of the skin of neck & branches to form phrenic nerve ( innervates diaphragm)
Brachial plexus- supplies muscles & skin of shoulder, axilla, arm, forearm, & hand Lumbosacral- supplies perineum, gluteal area thighs, legs & feet |
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Cranial Nerves
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12 cranial nerves- carries motor and/or sensory neurons
Nuclei – lie below cerebrum except for the olfactory & optic nerves |
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ANS
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Sympathetic Nervous System
Stress Parasympathetic- Conservation |
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Divisions Of Nervous System
(1) Central (2) Peripheral (3) Autonomic (4) Somatic |
Central nervous system ( CNS) brain and spinal cord –interprets incoming sensory information and sends out instruction based on past experiences
Peripheral nervous system ( PNS) : Cranial and spinal nerves extending out from brain and spinal cord---carry impulses to and from brain and spinal cord Autonomic nervous system: functional classification of the PNS---regulates involuntary activities Somatic nervous system: Functional classification of the PNS: --allows conscious or voluntary control of skeletal muscles |
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Autonomic Nervous System
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Sympathetic “Fight or Flight”
Mediator-norepinephrine Increased pupil size >HR Dilated Bronchioles <GI Tone Parasympathetic - “Conserve” Acetylcholine Decreased pupil size <HR Constricted bronchioles >GI Tone |
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Effects of Injury on the Nervous System
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Regeneration
Effects of aging on the nervous system |
