Physiology Long Test 4: Basic Features of the Nervous System
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Questions and Answers

What percentage of the blood flow from the heart is received by the brain?

  • 40%
  • 20% (correct)
  • 30%
  • 10%

    • What is the function of the blood-brain barrier?

  • To guard the brain chemically (correct)
  • To filter out oxygen from the brain
  • To increase glucose storage in the brain
  • To interrupt blood flow to the brain

    • How long can the brain survive without oxygen before permanent damage occurs?

  • 2 minutes
  • 5 minutes
  • A few minutes (correct)
  • 1 minute

    • What is the term for the imaginary line drawn through the length of the central nervous system?

    <p>Neuraxis</p> Signup and view all the answers

    What is the term for the direction towards the nose and mouth?

    <p>Rostral</p> Signup and view all the answers

    What is the function of cerebrospinal fluid (CSF)?

    <p>To float the brain in a protective pool</p> Signup and view all the answers

    What term refers to structures on the opposite side of the body?

    <p>Contralateral</p> Signup and view all the answers

    What is the main purpose of the meninges?

    <p>To protect the brain and spinal cord</p> Signup and view all the answers

    Which layer of the meninges is closely attached to the brain and spinal cord?

    <p>Pia mater</p> Signup and view all the answers

    What is the purpose of the choroid plexus?

    <p>To produce CSF</p> Signup and view all the answers

    What is the total volume of CSF in the ventricular system?

    <p>~125 ml</p> Signup and view all the answers

    What is the result of a blockage in CSF flow?

    <p>Hydrocephalus</p> Signup and view all the answers

    Study Notes

    Basic Features of the Nervous System

    • The nervous system consists of two key systems: Central Nervous System (CNS) and Peripheral Nervous System (PNS).
    • CNS consists of the brain and spinal cord, encased in bone.

    Central Nervous System (CNS)

    • Brain:
      • Made up of neurons, glia, and other supporting cells.
      • Receives approximately 20% of the blood flow from the heart, continuously.
      • Most protected organ in the body, encased in a tough, bony skull and floating in a pool of cerebrospinal fluid (CSF).
      • Chemically guarded by the blood-brain barrier.
      • Can store only a small amount of glucose and cannot function without oxygen.
      • 1-second interruption of blood flow uses up much of the dissolved oxygen, and 6-second interruption produces unconsciousness.
    • Spinal cord:
      • Contained within the vertebral column.

    Peripheral Nervous System (PNS)

    • Consists of:
      • Cranial nerves
      • Spinal nerves
      • Peripheral ganglia

    Anatomical Directions

    • Anterior vs. Posterior: front end vs. tail end
    • Rostral vs. Caudal: toward nose and mouth vs. toward tail
    • Dorsal vs. Ventral: back/top surface vs. belly/front surface
    • Superior vs. Inferior: above (brain-specific) vs. below (brain-specific)
    • Lateral vs. Medial: toward the side vs. toward the middle
    • Neuraxis: imaginary line drawn through the length of the CNS, from the lower end of the spinal cord up to the front of the brain.

    Brain Sections

    • Cross-sections (frontal section): sliced like bread, dividing into front and back halves
    • Horizontal sections: parallel to the ground, dividing into upper and lower halves
    • Sagittal sections: parallel to the neuraxis, dividing into right and left halves
    • Midsagittal plane: splits the brain symmetrically

    Meninges

    • Protective sheaths around the brain and spinal cord
    • Three layers:
      • Dura mater (outer layer): durable, thick, tough, and flexible but unstretchable
      • Arachnoid membrane (middle layer): soft and spongy, with arachnoid trabeculae
      • Pia mater (inner layer): closely attached to the brain and spinal cord, with smaller surface blood vessels

    Ventricular System and CSF Production

    • Ventricular system: series of interconnected chambers filled with CSF
    • Ventricles:
      • Produce and contain CSF
      • Lateral ventricles: largest chambers of the ventricular system
    • Cerebral aqueduct: connects third ventricle to fourth ventricle
    • Choroid plexus: special tissue with rich blood supply, manufactures CSF, and protrudes into all four ventricles
    • Total CSF volume: ~125 ml
    • Half-life of CSF: ~3 hours
    • CSF flow: produced in lateral ventricles, flows to third ventricle, passes through cerebral aqueduct to fourth ventricle, and circulates around CNS before being reabsorbed into blood.

    Cerebrospinal Fluid (CSF)

    • Reduces brain's effective weight from ~1,400 g to ~80 g
    • Cushions brain, reducing impact from sudden movements
    • May cause hydrocephalus (obstructive) if CSF flow is blocked

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    Description

    This quiz covers the fundamental features of the nervous system, including the central nervous system and its components. Learn about the brain, spinal cord, and their functions.

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