Neuroanatomy Lecture Notes
Overview
- Basic concepts of the nervous system.
- Divisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS).
- Components: Brain and spinal cord (CNS); sensory and motor nerves (PNS).
Central Nervous System (CNS)
- Components: Brain and spinal cord.
- Functions:
- Collects information from the environment and body via sensory systems.
- Processes, compares, and contrasts information with past experiences.
- Stores sensory input and integrates new information with stored data.
- Decides on motor responses and generates output.
- Flow of Information: Sensory input goes to CNS -> CNS processes and makes decisions -> Motor output is generated.
Peripheral Nervous System (PNS)
- Divisions: Sensory and motor parts.
- Functions:
- Takes sensory info from periphery to CNS.
- Carries motor decisions from CNS to peripheral tissues.
Sensory System
- Divisions: Special senses and general senses.
- Special Senses: Elicited from specific body parts (eyes, nose, tongue, ears).
- General Senses: Can be felt from multiple body parts (touch, temperature).
- Somatic Sensations: From skin, subcutaneous tissue, locomotor system. Includes pain, temperature, touch, and proprioception.
- Visceral Sensations: From internal organs; often result in dull pain, discomfort from distension, etc.
Motor System
- Types of Motor Responses: Voluntary (somatic) and involuntary (autonomic).
- Voluntary (Somatic): Controlled consciously (skeletal muscles).
- Involuntary (Autonomic): Not under conscious control (smooth muscles, glandular secretions).
- Autonomic Nervous System:
- Sympathetic: Increases activity under stress (fight/flight response).
- Parasympathetic: Dominates when relaxed (rest and digest).
Brain Anatomy
- Divisions of the Brain:
- Hindbrain (Rhombencephalon): Medulla, pons, cerebellum.
- Midbrain (Mesencephalon): Central part of the brain.
- Forebrain (Prosencephalon): Cerebral hemispheres (telencephalon) and deeper structures (diencephalon).
- Gray Matter vs White Matter:
- Gray Matter: Collections of neuronal cell bodies (cortex if on the surface, nucleus if deeper and surrounded by white matter).
- White Matter: Bundles of axons connecting different parts of the CNS.
- Tracts: Bundles of axons moving up and down (ascending and descending).
- Commissural Fibers: Connect right and left parts of the brain.
- Association Fibers: Connect front and back parts of the brain.
- Reticular Formation: Network of mixed gray and white matter in the brainstem.
Neurons and Glial Cells
- Neurons: Conduct electrochemical information (action potentials).
- Glial Cells (Neuroglia): Support neurons.
Additional Concepts
- Proprioception: Sense of body position, important for coordination and movement.
- Conscious vs Unconscious Sensory Input: Some sensory information reaches conscious awareness (processed by the cerebral cortex), while other information does not.
- Nerves vs Tracts:
- Nerves: Collection of axons outside CNS.
- Tracts: Collection of axons within CNS.
- Myelination: Nerves are myelinated by Schwann cells; tracts by oligodendrocytes.
Diseases
- Different diseases can affect either Schwann cells or oligodendrocytes, leading to demyelination and conduction problems in the PNS and/or CNS.
This is a summary of the key points and concepts covered in the lecture on basic neuroanatomy.