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Anatomy & Physiology: Central Nervous System and Peripheral Nervous System

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Termini in questo insieme (29)

  • Central nervous system (CNS)

    Consists of the brain and spinal cord.

  • Cephalization

    Evolutionary development of the rostral (anterior) portion of CNS, resulting in increased neurons and highest level reached in human brain.

  • Primary brain vesicles

    Three vesicles formed from anterior neural tube: prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain).

  • Secondary brain vesicles

    Derived from primary vesicles: forebrain → telencephalon and diencephalon; midbrain remains undivided; hindbrain → metencephalon and myelencephalon.

  • Cerebral hemispheres

    Formed from telencephalon; largest part of brain, accounting for 83% of brain mass.

  • Gray matter vs. white matter in CNS

    Gray matter: neuron cell bodies and nonmyelinated neurons; white matter: myelinated and nonmyelinated axons.

  • Ventricles of the brain

    Fluid-filled chambers continuous with central canal of spinal cord, filled with cerebrospinal fluid (CSF), lined by ependymal cells.

  • Major sulci and fissures of cerebral hemispheres

    Longitudinal fissure separates hemispheres; central sulcus separates frontal and parietal lobes; lateral sulcus outlines temporal lobe.

  • Cerebral cortex functions

    Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory, and understanding.

  • Primary motor cortex location and function

    Located in precentral gyrus of frontal lobe; controls precise, skilled voluntary movements via pyramidal cells.

  • Broca's area

    Motor speech area usually in left hemisphere; directs muscles for speech production and planning voluntary motor activities.

  • Primary somatosensory cortex

    Located in postcentral gyrus of parietal lobe; receives general sensory input from skin and proprioceptors; capable of spatial discrimination.

  • Thalamus function

    Relay station for sensory information to cortex; mediates sensation, motor activities, cortical arousal, learning, and memory.

  • Hypothalamus functions

    Main visceral control center vital for homeostasis; regulates autonomic nervous system, emotions, body temperature, hunger, thirst, sleep-wake cycles, and endocrine functions.

  • Brain stem components

    Includes midbrain, pons, and medulla oblongata; controls automatic survival behaviors and contains nuclei for 10 of 12 cranial nerves.

  • Cerebellum functions

    Coordinates precise skeletal muscle movements and balance; processes input from cortex, brain stem, and sensory receptors.

  • Limbic system

    Includes structures in medial cerebral hemispheres and diencephalon; involved in emotion, memory, and motivation.

  • Reticular activating system (RAS)

    Maintains consciousness and alertness by sending impulses to cerebral cortex; filters out repetitive or weak stimuli.

  • Cranial nerves

    Twelve pairs of nerves associated with brain; numbered I to XII; functions include sensory, motor, or both.

  • Sensory receptor classification by stimulus type

    Includes mechanoreceptors (touch, pressure), thermoreceptors (temperature), photoreceptors (light), chemoreceptors (chemicals), and nociceptors (pain).

  • Phasic vs. tonic receptors

    Phasic receptors adapt quickly to stimuli; tonic receptors adapt slowly or not at all (e.g., nociceptors).

  • Spinal cord gray and white matter organization

    Gray matter is central with dorsal and ventral horns; white matter surrounds gray matter and is divided into dorsal, lateral, and ventral columns.

  • Ascending sensory pathways

    Three-neuron chains transmitting sensory information to brain: first order (receptor to spinal cord), second order (spinal cord to thalamus), third order (thalamus to cortex).

  • Descending motor pathways

    Two types: direct (pyramidal) pathways for fast, skilled movements; indirect pathways for posture, balance, and coarse movements.

  • Nerve fiber regeneration in PNS

    Possible if soma intact; involves Wallerian degeneration, macrophage cleanup, axon growth through regeneration tube, and remyelination.

  • Blood-brain barrier (BBB)

    Selective barrier formed by tight junctions of capillary endothelium, basal lamina, and astrocyte feet; protects brain from harmful substances.

  • Cerebrospinal fluid (CSF) functions

    Provides buoyancy, protection, nourishment, and chemical signaling for CNS; produced by choroid plexus and circulated through ventricles.

  • Sleep stages

    Includes NREM (4 stages with increasing depth) and REM sleep; REM characterized by active brain, muscle paralysis, and dreaming.

  • Homeostatic imbalance: stroke (CVA)

    Ischemia causes brain tissue death; symptoms include paralysis and speech deficits; treated with tissue plasminogen activator (TPA).