Nervous Sytem – Basic Anatomy Student Notes

 

 

 

ORGANIZATION OF THE NERVOUS SYSTEM ❤️

Divided into two main systems:

• Central Nervous System (CNS): brain + spinal cord
• Peripheral Nervous System (PNS): nerves outside the CNS (cranial & spinal)

Functional divisions:

• Somatic Nervous System (SNS): voluntary control (skeletal muscles)
• Autonomic Nervous System (ANS): involuntary control (organs, glands)

– Sympathetic (fight/flight)

– Parasympathetic (rest/digest)

 

NEURON STRUCTURE ❤️❤️

• Cell body (soma)
• Dendrites: receive signals
• Axon: transmit impulses
• Axon terminals: release neurotransmitters
• Myelin sheath: increases impulse speed
• Nodes of Ranvier: gaps between myelin, site of saltatory conduction

Types of Neurons (Structure):

• Unipolar, Bipolar, Multipolar

Types of Neurons (Function):

• Sensory (afferent), Motor (efferent), Interneurons

NERVE CELLS ❤️❤️❤️

• Neurons: transmit electrical impulses
• Neuroglia (glial cells): support, nourish, protect neurons
  • Astrocytes: maintain blood-brain barrier (BBB)
  • Oligodendrocytes/Schwann cells: secrete myelin
  • Ependymal cells: secrete CSF
  • Microglia: engulf pathogens