Lecture Notes on the Nervous System
Summary
In today’s lecture, Dr. Sanagustín discussed the nervous system, including its anatomy and functions. He explained the system’s basic units (neurons), its major divisions (Central Nervous System and Peripheral Nervous System), their components, and how they communicate with different body parts. Additionally, he outlined the functional divisions of the nervous system into somatic and autonomic systems, detailing their specific roles in body functions.
Key Points from the Lecture
Basic Structure and Functions
- Nervous System: A set of organs made up of nervous tissue primarily consisting of neurons.
- Neuron Components:
- Soma (cell body): Contains the nucleus.
- Dendrites: Bring information to the soma.
- Axon: Transfers nervous impulses away from the soma.
- Teledendrites/Synapses: Connect with other neurons to transmit impulses.
- Function: Transfers information from external/internal receptors to the brain where it gets processed. Commands are then relayed to effectors (muscles, organs) which respond accordingly.
Divisions of the Nervous System
Central Nervous System (CNS)
- Includes the brain and spinal cord.
- Brain Components:
- Cerebrum: Largest part, divided into left and right hemispheres.
- Cerebellum: Located under the cerebrum, involved in motor control.
- Brainstem: Includes midbrain, pons (Bridge of Varolio), and medulla oblongata.
- Spinal Cord: A nervous tissue cord protected by the spinal column, connecting the brain to the body, and segmented into cervical, thoracic, lumbar, and sacral parts.
Peripheral Nervous System (PNS)
- Connects the CNS to limbs and organs.
- Main structures:
- Nerves: Bundles of neuron axons.
- Ganglia: Clusters of neuron somas.
- Includes 12 pairs of cranial nerves and 31 pairs of spinal nerves.
Substances in the Nervous System
- Gray Matter: Mainly soma of neurons; found peripherally in the cerebrum and centrally in the spinal cord.
- White Matter: Mainly axons; location is opposite to gray matter's within CNS structures.
Functional Divisions
Somatic Nervous System
- Voluntary control over body movements.
- Sensory information processing (sight, hearing, taste, touch).
- Motor pathways control skeletal muscle actions.
- Primary neurotransmitter: Acetylcholine.
Autonomic Nervous System (ANS)
- Involuntary control (heart rate, digestion).
- Divided into:
- Sympathetic Nervous System: Responsible for 'fight or flight' response; neurotransmitter is noradrenaline.
- Parasympathetic Nervous System: Manages 'rest and digest' functions; uses acetylcholine.
Conclusion
Dr. Sanagustín emphasized the complexities and overlapping functionalities within the nervous system and related biological systems. He clarified that the divisions used are for better understanding and teaching purposes.
Remember to review the diagrammatic representations shared during the lecture for visual reinforcement of the concepts discussed. Please feel free to refer to the textbook chapters covering the nervous system for additional details and context.