Lecture on Body Cell Diversity and Nervous System

Introduction to Body Cell Diversity

• Cells in the body are diverse in structure and function.
• Parietal Cells: Found in the stomach, produce stomach acid.
• Mast Cells: Part of the immune system, release histamine for inflammatory response.
• Skeletal Muscle Cells: Also known as muscle fibers, are cylindrical and multi-nucleated, essential for muscle contraction.
• Neurons: Specialized cells in the nervous system.

Overview of the Nervous System

Structure of the Nervous System

• Central Nervous System (CNS): Includes the brain and spinal cord.
• Peripheral Nervous System (PNS): Consists of nerves throughout the body, providing sensory information to the CNS and executing motor responses.

Central Nervous System (CNS)

The Brain

• Divided into three regions: hindbrain, midbrain, and forebrain.

Hindbrain

• Medulla: Regulates breathing, blood pressure, and heart rate.
• Pons: Coordinates signals to the brain.
• Cerebellum: Manages balance and movement coordination.

Midbrain

• Involved in alertness, sleep/wake cycle, and motor activity.

Forebrain

• Cerebrum: Divided into right and left hemispheres, responsible for speech, thinking, reasoning, and emotions.
• Thalamus: Involved with sensory and motor information.
• Hypothalamus: Controls the endocrine system.

Peripheral Nervous System (PNS)

Divisions of PNS

• Somatic Nervous System (SNS): Manages motor functions of skeletal muscles, includes voluntary actions and somatic reflexes.
• Autonomic Nervous System (ANS): Regulates internal environments, gastrointestinal, excretory, endocrine, smooth and cardiac muscle, and autonomic reflexes.

Divisions of ANS

• Sympathetic System: Manages fight or flight response, increases heart and breathing rate.
• Parasympathetic System: Manages rest and digest activities, decreases heart rate, and stimulates digestion.

Cells of the Nervous System

Neurons

• Structure: Consists of a cell body, dendrites (signal reception), and axon (signal transmission).
• Synapse: Junction where neurons communicate with other cells.

Glial Cells

• Support neurons and are essential for:
  • Maintaining chemical balance and the blood-brain barrier.
  • Producing myelin sheaths for insulation of axons.
  • Producing cerebrospinal fluid.
  • Providing immune functions.

Action Potential

• Neurons communicate using action potentials.
• Resting Potential: Neurons maintain a resting potential of -70 mV using ions like Na+ and K+.
• Depolarization: Na+ floods into the axon, making the charge more positive, causing the action potential to spread.
• Action potentials are "all or none" responses.
• Myelinated Neurons: Action potential jumps between nodes.

Neurotransmitter Release

• Action potential reaches axon terminals and causes neurotransmitter release into the synaptic cleft.
• Neurotransmitters bind to specific receptors on the next neuron to propagate the signal.

Recap

• Discussed CNS and PNS, major brain areas, PNS divisions, neuron and glial cell roles, action potential, and neurotransmitter release.
• Highlighted ongoing research and career opportunities in neurology.

The lecture concludes with a reminder to stay curious about the nervous system and its complexities, as further studies could provide more insights into its functions and related diseases.