Please enable JavaScript.

Coggle requires JavaScript to display documents.

Mae Stansbury, Period 5, Nervous System - Coggle Diagram

- - - - Central nervous system (CNS): brain and spinal cord of Doral body cavity; integration and control center
      - Peripheral nervous system (PNS): the portion of nervous system outside CNS; consists mainly of nerves that extend from brain and spinal cord
        
        Has 2 functional divisions
        
        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
        
        Motor (efferent) divisions: transmits impulses from CNS to effector organs with two divisions
        
        Somatic Nervous system (voluntary): somatic motor nerve fibers conduct impulses from CNS to skeletal muscles; conscious control of skeletal muscles
        
        Autonomic nervous system (involuntary): consists of visceral motor nerve fibers; regulates smooth muscle, cardiac muscle, and glands, has 2 functional subdivisions (sympathetic and parasympathetic)
- - - - Sensory (efferent) division: somatic sensory fibers convey impulses from skin, skeletal muscles, and joints to CNS; visceral sensory fibers convey impulses from visceral organs to CNS
      - Motor (efferent) divisions: transmits impulses from CNS to effector organs
        
        Somatic Nervous system (voluntary): somatic motor nerve fibers conduct impulses from CNS to skeletal muscles; conscious control of skeletal muscles
        
        Autonomic nervous system (involuntary): consists of visceral motor nerve fibers, regulates smooth muscles, cardiac muscle, and glands
        
        sympathetic
        
        parasympathetic
- - - - Astocytes: most abundant, versatile, and highly branched of glial cells; cling to neurons, synaptic endings, and capillaries, functions are to support and brace neurons, play a role in exchange between capillaries and neurons, guide migration of young neurons, control chemical impulses and neurotransmitters, influence neuronal functioning, participate in information processing in brain
      - Microglial cells: small ovoid cells with thorny processes that touch and monitor neurons; migrate toward injured neurons, can transform to phagocytize microorganisms and neuronal debris
      - Ependymal cells: range in shape from squamous to columnar, may be ciliated; line central cavities of the brain and spinal column; form permeable barrier between cerebrospinal fluid in cavities and tissue fluid bathing CNS cells
      - Oligodendrocytes: branched cells; processes wrap CNS nerve fibers forming insulating myelin sheaths in thicker nerve fibers
    - - Satellite cells: surround neuron cell bodies in PNS; function similar to astrocytes of CNS
      - Schwann cells (neurolemmocytes) surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers; vital to regeneration of damaged peripheral nerve fibers
- - - - Forms the superior part of the Brain and 83% of the mass
      - There are 5 surface markings
        
        Gyri: ridges
        
        Sulci: shallow grooves
        
        Several sulci divide each hemisphere into 5 lobes; all lobes except insula are named after overlying skull bones
        
        Occipital
        
        Frontal
        
        Parietal
        
        Temporal
        
        Insula
        
        Insular lobe is buried under portions of temporal, parietal, and frontal lobes
        
        Major sulci that divide lobes
        
        Central sulcus: separates precentral gyrus of frontal lobe and postcentral gyrus of parietal lobe
        
        Parieto-occipital sulcus: separates occipital and parietal lobes
        
        Lateral sulcus: outlines temporal lobes
        
        Fissures: deep grooves
        
        Longitudinal Fissure: separates 2 hemispheres
        
        Transverse Cerebral Fissure: separates cerebrum and cerebellum
      - Each hemisphere has 3 basic regions
        
        Cerebral Cortex of gray matter superficially
        
        Executive suite of brain; site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding
        
        Thin (2-4mm) superficial layer of gray matter made up of neuron cell bodies, dendrites, glial cells, and blood vessels (no axons)
        
        40% of brain mass
        
        4 general considerations of cerebral cortex
        
        Contains 3 types of functional areas
        
        Motor Areas: control voluntary movement
        
        located in frontal lobe, motor Areas act to control voluntary movement
        
        Primary motor cortex in precentral gyrus: sompatopy-all muscles of body can be mapped to area on primary motor cortex; motor homunculi-upside-down caricatures represent contralateral motor innervation of body regions
        
        Premotor cortex: helps plan movements; controls learned, repetitious, or patterned motor skills; coordinates simultaneous or sequential actions; controls voluntary actions that depend on sensory feedback
        
        Broca's Area: present in one hemisphere (usually left); motor speech area that directs muscles of speech production; active in planning speech and voluntary motor activities
        
        Frontal eye field within and anterior to premotor cortex; superior to Broca's area
        
        Sensory Areas: conscious awareness of sensation
        
        areas of cortex concerned with conscious awareness of sensation; occur in parietal, insular, and occipital lobes
        
        Eight main areas
        
        8 more items...
        
        Multimodal Association Areas: recieves inputs from multiple sensory Areas; send outputs to multiple areas; allows us to give meaning to information received, store in memory, tie to previous experience, and decide on actions; sensations, thoughts, emotions become conscious- makes us who we are; broadly divided into 3 parts: anterior association area, posterior association area, and limbio association area
        
        Association Areas: integrate diverse information
        
        Each hemisphere is concerned with contralateral side of body
        
        Lateralization of cortical functioning: lateralization- division of labor between hemispheres; cerebral domincance- refers to hemisphere that is dominant for language; 90% of human have left-sided dominance; usually results in right handedness; in other 10% roles of hemispheres are reversed
        
        Left Hemisphere: controls language, math, and logic
        
        Right Hemisphere: visual-spatial skills, intuition, emotion, and artistic and musical talents
        
        Hemispheres communicate almost instantaneously via fiber tracts and functional integration
        
        Lateralization of cortical function can occur only one hemisphere
        
        Conscious behavior involves entire cortex in one at or another
        
        White matter internally
        
        Basal nuclei deep within white matter
    - - made of 3 paired gray matter structures: thalamus, hypothalamus, epithalamus and all 3 enclose the third ventricle
        
        Thalamus: acts as a relay station for information coming into cortex; sorts, edits, and relays ascending input like impulses from hypothalamus for regulating emotion and visceral function; impulses from cerebellum and basal nuclei to help direct motor cortices; impulses for memory or sensory integration; overall acts to mediate sensation, motor activities, cortical arousal, learning, and memory
        
        Hypothalamus: located below thalamus; forms cap over brain stem and forms inferolateral walls of third ventricle; contains many important nuclei like mammillary Bodies paired anterior nuclei that act as olfactory relay stations and infundibulum stalk that connects to pituitary gland; hypothalamus is the main visceral control and regulating center that is vital to homeostasis; regulates body temp; regulates hunger and satiety in response to nutrient blood levels or hormones; regulates water balance and thirst; regulates sleep-wake cycles; controls endocrine system functions
        
        Epithalamus: most dorsal portion of diencephalon; forms roof of third ventricle; has pineal gland; extends from posterior border; secretes melatonin that helps regulate sleep-wake cycle
    - - Midbrain: located between diencephalon and pons; cerebral peduncles: 2 ventral bulges that contain pyrimidal motor tracts; cerebral aqueduct: channel running through midbrain that connects 3rd and 4th ventricles midbrain nuclei scattered throughout white matter; corpora quadrigemina: paired doral protrustions; substantia nigra: functionally linked to basal nuclei
      - Pons: located between midbrain and medulla oblongata; 4th ventricles separates pons from cerebellum; some nuclei play role in reticular formation and some help maintain normal rhythm or breathing
      - Medulla: medulla; blends into spinal cord at foramen Magnum; contains 4th ventricle; continuation of central canal of spinal cord; medulla and pons form ventral wall; has choroid plexus: capillary rich membrane that forms cerebral spinal fluid; Cardiovascular center: cardiac center adjusts force and rate of heart contraction, vasomotor center adjusts blood vessel diameter for blood pressure regulation; Respiratory centers: generate respiratory rhythm, control rate and depth of breathing; vomiting, hiccupping, swallowing, coughing, sneezing
    - - Gray matter: short, no myelinated neurons and cell bodies
      - White Matter: myelinated and no myelinated axons
      - Basic pattern found in CNS: central cavity surrounded by gray matter with white matter external to gray matter
      - 11% of brain mass
      - loacated dorsal to pons and medulla
      - cerebellar hemispheres connected by worm-like vermis
      - has thin cortex of gray matter with distinctive treelike pattern of white matter called arbor vitae
      - purkinje fibers originate in cortex, synapse, with cerebellum
      - Cerebellar homunculi how sensory maps of entire body
      - Processes input from cortex, brain stem, and sensory receptors to provide precise coordinated movements of skeletal muscles
      - Plays role in thinking, language, and emotion
      - balance and coordination
- - - - Generation of end plate potential; ACh is released from motor neuron binds to ACh receptors on sarcolemma; causes chemically gated ion channels on sarcolemma to open and Na+ diffuses into muscle fiber; since Na+ diffuses in interior of sarcolemma becomes less negative; results in local depolarization called end plate potential
      - Depolarization: generation and propagation of action potential; if end plate potential causes enough change in membrane voltage to reach critical level known as threshold, voltage gated Na+ channels in membrane will open; large influx of Na+ through channels into cells triggers AP that is unstoppable and will lead to muscle fiber contraction; AP spreads across sarcolemma from one voltage gated Na+ channel to next one in adjacent areas making areas depolarize
      - Repolarization: restoring of resting conditions; Na+ voltage gated channels close and voltage gated K+ channels open; K+ efflux out of cell rapidly brings cell back to initial resting membrane voltage; Refractory period: muscle fiber cannot be stimulated for a specific amount of time until repolarization is complete; ionic conditions of resting state are restored by Na+ through K+ pump
    - - Resting State: all gated Na+ and K+ channels are closed
      - Depolarization: Na+ channels open
      - Repolarization: Na+ channels are inactivating and K+ channels open
      - Hyperpolarization: some K+ channels remain open and Na+ channels reset
- - - - Decussation: most pathways cross from one side of CNS to other at some point
      - Relay: consist of chain of 2 or 3 neurons
      - Somatotopy: precise spatial relationship in CNS correspond to spatial relationship in body
      - Symmetry: pathways are paired symmetrically
- - - - SNS: all somatic motor neurons release acetylcholine (ACh); effect is always stimulatory
      - ANS: preganglionic fibers release ACh; postganglionic fibers release norepinephrine or ACh at effectors; effect is either stimulatory or inhibitory depending on type of receptors