Neurology:

Is the branch of medicine that deals with diseases of the nervous system.

Nervous system divided into:

Central nervous system (CNS)

Peripheral nervous system (PNS)

Autonomic nervous system (ANS)

Two cerebral hemispheres Connected to:

1. each other by the corpus callosum

2 .brain stem by cerebral peduncles

EACH CEREBRAL HEMISPHERE DIVIDED

INTO four lobes:

1. Frontal

2. Parietal

3. Temporal

• Located behind the brain stem

• Responsible for coordination and balance

• Helps control movement and posture

• Controls fine motor skills

• Inside spinal canal

• End at the lower border of L1

• The lowest 3 segments = Conus

• The above 4 segments = Epiconus

• Inner grey mater and outer white

matte

Lumbosacral roots collection fills the lower part of the spinal canal below L1

. A.H.Cs

. Roots

. Plexuses

. Peripheral nerves

Nervous system is the most complex system in the body.

It is distributed throughout the body.

Nervous system is formed by :

1- Neurons.

2- Neuroglial cells(supporting cells)

• Basic structural and functional unit of the nervous system

• Responsible for transmitting electrical and chemical signals

• Main parts:

• Cell body (soma): contains nucleus

• Dendrites: receive signals

• Axon: sends signals

• Function: communication within the body

• Non-excitable supporting cells of the nervous system

• Do not transmit nerve impulses

• Functions:
  • Support and protect neurons
  • Provide nutrients
  • Maintain the environment
  • Form the myelin sheath (increases signal speed)

• A nerve is a bundle of nerve fibers (axons)

• Surrounded by connective tissue layers: Endoneurium, Perineurium, Epineurium

• Contains blood vessels

• Appears whitish due to myelin and collagen
  Function:

• Connects CNS with sense organs and effectors
  Types:

• Sensory nerves

• Motor nerves

• Mixed nerves

Nerve Fiber

• A nerve fiber = single axon + Schwann cell sheath

• May be myelinated or unmyelinated
  Structure:

• Axon: carries impulses

• Myelin sheath: increases speed

• Schwann cells: form the sheath

• Nodes of Ranvier: gaps that speed transmission

Large axons are engulfed by Schwann cells,
where their plasma membrane fuses with itself around the axon, forming the mesaxon.
The mesaxon wraps around the axon many times, forming the myelin sheath.
Myelin is a lipoprotein complex that is removed by standard histological procedures,
so to demonstrate it, a special stain is used: osmic acid stain,
which appears dark brown or black in light microscopic images.

Ovoid structures consist of neuronal cells, supportive cells, Schwann cells, and satellite cells.
These cells are supported by fibrocollagenous tissue.
They serve as relay stations to transmit nerve impulses.
There are two types of ganglia:

• Sensory ganglia

• Autonomic ganglia