Nervous System Overview Quiz

Nervous System Overview

• The nervous system is responsible for receiving information from various senses, integrating that information, and producing a rapid response.
• Key functions include muscle contraction, glandular secretion, thought, and emotions.

Central Nervous System (CNS)

• The CNS is composed of the brain and spinal cord.
• The brain is protected by the skull, while the spinal cord is encased in the vertebral column.
• Meningeal membranes, including dura mater, arachnoid, and pia mater, protect the CNS and blood vessels.
• Cerebrospinal fluid fills the space between the arachnoid and pia mater, acting as a shock absorber and isolating the CNS from infections.
• The blood-brain barrier prevents certain substances from entering the brain.

Brain Lobes

• The brain is divided into four lobes: frontal, parietal, occipital, and temporal.
• Each lobe plays a role in specific functions such as thought, memory, vision, and language.
• The insula is occasionally considered a fifth lobe, located deep within the temporal lobe.

Brain Structures

• Cerebrum:
  • Largest part of the brain.
  • Responsible for thought, language, senses, memory, and voluntary movement.
• Cerebellum:
  • Located at the base of the brain.
  • Responsible for muscle coordination, balance, and posture.
• Brain Stem:
  • Connects the brain to the spinal cord.
  • Controls breathing, swallowing, heartbeat, and blood pressure.

Spinal Cord

• Extends from the base of the skull to the area of the second lumbar vertebra.
• Composed of nerve cells and nerves that transmit messages between the brain and the body.
• Protected by the vertebral column.

Neuron

• Contains a cell body with a nucleus, mitochondria, and other organelles.
• Dendrites receive messages from other neurons.
• Axons send messages to other neurons.
• Neurons do not physically touch, instead there is a gap called a synapse.
• Neurotransmitters are chemicals responsible for transmitting messages across synapses.

Neuroglial Cells

• Support and protect neurons.
• Do not generate or transmit impulses.
• CNS:
  • Microglia: Immune cells of the CNS.
  • Ependymal cells: Line cavities of the CNS and produce cerebrospinal fluid.
  • Astrocytes: Provide structural support, regulate blood flow, and assist with nutrient transport in the CNS.
  • Oligodendrocytes: Produce myelin in the CNS.
• PNS:
  • Schwann cells: Produce myelin in the PNS.
  • Satellite cells: Support and protect neuron cell bodies in the PNS.

Membrane Potential

• The sodium-potassium pump actively transports 3 sodium ions out of the cell in exchange for 2 potassium ions, maintaining the resting potential.
• Some potassium ions leak out of the cell, making the inside of the cell more negative than the outside.

Disorders of the Nervous System

• Parkinson's disease: Motor disorder caused by neurodegeneration in the substantia nigra, part of the basal ganglia.
• Alzheimer's disease: Neurodegenerative disorder that leads to memory loss.
• Epilepsy: Common condition affecting the brain, causing seizures due to bursts of electrical activity.
• Paralysis: Loss of sensation and movement in a part of the body resulting from injury to the spinal cord or brain.