Untitled Quiz

Introduction to Neuroanatomy

• Lecture by Prof Dr Mohamed El-Badry Mohamed
• Professor of Human Anatomy and Embryology, Merit University
• Professor of Human Anatomy and Embryology, Assiut University

Objectives of the Lecture

• Students will be able to identify the organs of the central nervous system.
• Students will be able to identify the structures of the peripheral nervous system.
• Students will be able to recognize the types of autonomic nervous systems and their locations.
• Students will be able to describe the anatomy of cells in the central nervous system and their functions.
• Students will be able to name the cavities of the brain and their locations.
• Students will be able to identify the lobes of the cerebral hemispheres and their functions.
• Students will be able to describe the structure of gray and white matter of the brain.
• Students will be able to determine the number of spinal nerves and their distribution.
• Students will be able to list the cranial nerves.

Nervous System

A. Somatic Nervous System

1. Central nervous system

 - Brain:  cerebrum, cerebellum, brain stem (midbrain, pons, medulla oblongata)
 - Spinal cord

2. Peripheral nervous system

 - Cranial nerves (12 pairs)
 - Spinal nerves (31 pairs)
     - 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal

B. Autonomic Nervous System

1. Sympathetic nervous system

 - Thoraco-lumbar (T1-L2)

2. Parasympathetic nervous system

 - Cranio-sacral (Cr III, VII, IX, X, and S2,3,4)

Cerebrum

• Two cerebral hemispheres connected by the corpus callosum.
• Composed of outer cortex (grey matter) and inner medulla (white matter).

Grey Matter

• Primarily cell bodies of nerve cells.
• Includes glial cells (astrocytes, protoplasmic and fibrous, oligodendrocytes, microglia).
  • Astrocytes provide structural and nutritional support to neurons.
  • Oligodendrocytes form myelin sheaths in the CNS.
  • Microglia are phagocytes of the CNS.

White Matter

• Consists mainly of nerve fibers and glial cells.

Classification of Neurons

I. Based on the Number, Length, and Branching of Neurites

• Unipolar: single neurite; posterior root ganglion
• Bipolar: single neurite from either end of cell body; retina, sensory cochlea, and vestibular ganglia
• Multipolar: many dendrites and one long axon; fiber tracts of brain and spinal cord, peripheral nerves, and motor cells of spinal cord

II. Based on Size

• Golgi type I: single, long axon; fiber tracts of brain and spinal cord, peripheral nerves, motor cells of spinal cord
• Golgi type II: short axon with dendrites that resembles a star; cerebral and cerebellar cortex.

Neuroglial Cells

• Diagrammatic representation of different types of neuroglial cells showing their arrangement.
  • Ependyma
  • Protoplasmic astrocytes
  • Fibrous astrocytes
  • Oligodendrocytes
  • Microglial cells
  • Capillary
  • Neuron

Lobes of the Cerebrum

• Frontal lobe: motor, cognition
• Parietal lobe: general somatic sensation
• Temporal lobe: hearing
• Occipital lobe: vision

Basal Ganglia

• Nuclei buried within the white matter.
• Includes: Caudate nucleus, Putamen, Globus pallidus, Claustrum, Amygdaloid body.

Diencephalon

• Located between the brain stem and cerebral hemispheres.
• Includes: Epithalamus, Thalamus, Subthalamus, Hypothalamus, and Metathalamus.

Brain Stem

• Structures: Medulla oblongata, Pons, and Midbrain.

Cerebellum

• Largest part of the hindbrain
• Originates from the dorsal aspect of the brain stem
• Overlies the 4th ventricle
• Connected to the brain stem by three pairs of fiber bundles (superior, middle, inferior cerebellar peduncles).

Cranial Nerves

• Originate in the brain and exit through foramina.
• Distributed in the head and neck, except the vagus nerve (cranial nerve 10).
  • 12 pairs of cranial nerves: olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, hypoglossal.