Nerv 2

• Central nervous system (CNS)


  Brain and spinal cord
• Peripheral nervous system (PNS)


  All nerves
• Autonomic nervous system (ANS)


  Part of the nervous system
• Central nervous system (CNS)


  • 85 billion neurons
  • Allows us to subconsciously regulate homeostatic responses
  • Experience emotions
  • Voluntarily control movements
  • Be aware of body and surroundings
  • Engage in other higher cognitive processes
• Divisions of the brain

  • Brainstem
  • Cerebellum
  • Diencephalon
  • Cerebrum
• Brainstem


  • Consists of medulla oblongata, pons, and midbrain
  • White matter with bits of gray matter scattered through it
  • Conducts impulses to the higher parts of the brain
• Brainstem


  • Vital link between the spinal cord and higher brain regions
  • Area where most cranial nerves arise
  • Contains centers that control cardiovascular, respiratory, and digestive function
  • Regulates equilibrium and postural reflexes
  • Controls overall degree of cortical alertness
  • Contains centers that govern sleep
• Cerebellum


  • Second largest part of the human brain
  • Arbor vitae (Latin for "tree of life"): Internal, treelike network of white matter tracts
  • A highly folded, baseball-sized part of the brain that lies underneath the cortex's occipital lobe
• Cerebellum


  • Helps control muscle contractions to produce coordinated movements for maintaining balance, moving smoothly, and sustaining normal postures
  • Variety of additional coordinating effects, assisting the cerebrum and other regions of the brain
• Parts of the cerebellum

  • Vestibulocerebellum
  • Spinocerebellum
  • Cerebrocerebellum
• Diencephalon


  • Consists mainly of the posterior pituitary gland, pituitary stalk, and gray matter
  • Acts as the major center for controlling the ANS, therefore helping control the functioning of most internal organs
  • Controls hormone secretion by anterior and posterior pituitary glands, therefore indirectly helping control hormone secretion by most other endocrine glands
  • Contains centers for controlling body temperature, appetite, wakefulness, and pleasure
• Thalamus


  • Sensory relay station and is important in motor control
  • Produces the emotions of pleasantness or unpleasantness associated with sensations
• Pineal gland (pineal body)


  • Small body resembling a pine nut behind the thalamus
  • Adjusts output of "time-keeping hormone" melatonin in response to changing levels of external light (sunlight and moonlight)
• Cerebrum


  • Largest part of the human brain
  • Outer layers of gray matter are the cerebral cortex, made up of lobes and composed mainly of dendrites and cell bodies of neurons
  • Interior of the cerebrum composed mainly of white matter tracts
  • Basal nuclei: Islands of gray matter that regulate automatic movements and posture
  • Responsible for mental processes of all types, including sensations, consciousness, memory, and voluntary control of movements
• Lobes of the cerebral cortex

  • Occipital
  • Temporal
  • Parietal
  • Frontal
• Cerebral cortex


  • Highly convoluted appearance, consisting of sulci (grooves or depressions) and gyri (ridges or elevations)
• Parietal lobes


  Accomplish somatosensory processing: Sensations from the surface of the body, such as touch, pressure, heat, cold, and pain
• Primary motor cortex


  Located in the frontal lobes, controls the skeletal muscles
• Higher motor areas


  • Supplementary motor area
  • Premotor cortex
  • Posterior parietal cortex
• Plasticity


  Ability of the brain to change or be functionally remodeled in response to demands
• Broca's area and Wernicke's area

  Different regions of the cortex that control different aspects of language
• Specialization in the cortex

  • Left cerebral hemisphere: Logical, analytical, sequential, and verbal tasks
  • Right cerebral hemisphere: Non-language skills
• Default mode network


  Most active when the mind wanders, more active during resting states than during focused tasks
• Spinal cord


  • 43 to 45 cm long
  • Columns of white matter, composed of bundles of myelinated nerve fibers (tracts)
  • Interior composed of gray matter made up mainly of neuron dendrites and cell bodies (H-shaped)
  • Provides two-way conduction paths: Ascending and descending
  • Functions as the primary center for all spinal cord reflexes; sensory tracts conduct impulses to the brain, and motor tracts conduct impulses from the brain
• Spinal nerves


  • Carry both afferent and efferent fibers
  • Connect with each side of the spinal cord by a dorsal root and a ventral root
• Reflex arc


  • Sensory receptor
  • Afferent pathway
  • Integrating center
  • Efferent pathway
  • Effector organ
• Coverings of the brain and spinal cord

  • Cerebral and spinal meninges
  • Dura mater
  • Pia mater
  • Arachnoid mater
• Fluid spaces of the brain and spinal cord


  • Subarachnoid spaces of meninges
  • Central canal inside spinal cord
  • Ventricles in brain
• Cerebrospinal fluid (CSF)


  • Surrounds and cushions the brain and spinal cord
  • Highly selective blood–brain barrier regulates exchanges between the blood and brain
  • Shields from harmful changes
• A lumbar puncture (spinal tap) is a test used to diagnose certain health conditions. It's performed in the lower back, in the lumbar region.