Overview
This lecture covers the structure and function of the nervous system, emphasizing its components, key processes, and neurotransmitters, with a focus on nursing implications and medication management for neurologic disorders.
Structure of the Nervous System
- The nervous system regulates and coordinates all body functions, enabling response to the environment.
- It is divided into the central nervous system (CNS) and peripheral nervous system (PNS).
Central Nervous System (CNS)
- CNS is the command center for processing sensory information and issuing commands.
- Consists of the brain and spinal cord.
- Brain regions:
- Cerebrum: controls higher functions like reasoning, memory, speech, and voluntary movement.
- Cerebellum: coordinates movement, balance, and posture.
- Brainstem (midbrain, pons, medulla oblongata): regulates breathing, heart rate, and sleep cycles.
- Spinal cord relays commands between brain and body, and manages reflex responses.
Peripheral Nervous System (PNS)
- PNS includes all nerves outside the CNS, connecting it to the body.
- Divided into somatic and autonomic nervous systems.
- Somatic nervous system controls voluntary movement and reflexes via afferent (sensory) and efferent (motor) neurons.
- Autonomic nervous system regulates involuntary functions like heart rate, digestion, and gland activity.
Branches of the Autonomic Nervous System
- Sympathetic nervous system: triggers "fight or flight" responses (increased heart rate, blood pressure, pupil dilation, reduced digestion, adrenaline release).
- Parasympathetic nervous system: triggers "rest and digest" responses (slowed heart rate, increased digestion, relaxation, pupil constriction).
Neural Communication and Neurotransmitters
- Neurons communicate via electrical impulses (action potentials) and chemical signals (neurotransmitters) at synapses.
- Myelin increases the speed of nerve impulses.
- Neurotransmitters include acetylcholine (muscle activation, memory), dopamine (mood, motivation, motor), serotonin (mood, sleep, appetite), norepinephrine (alertness, stress), and GABA (inhibits excessive activity).
Clinical Implications for Nurses
- Understanding neurotransmitters is key because medications for neurologic disorders aim to adjust their levels.
- Medication management focuses on either increasing or decreasing certain neurotransmitters depending on patient needs.
Key Terms & Definitions
- Central Nervous System (CNS) — Brain and spinal cord; main processing center.
- Peripheral Nervous System (PNS) — Nerves outside the CNS; connects CNS to the body.
- Neuron — Specialized nerve cell transmitting electrical and chemical signals.
- Neurotransmitter — Chemical messenger enabling communication between neurons.
- Somatic Nervous System — Controls voluntary movements.
- Autonomic Nervous System — Regulates involuntary body functions.
- Sympathetic Nervous System — Activates fight-or-flight response.
- Parasympathetic Nervous System — Activates rest-and-digest functions.
Action Items / Next Steps
- Review upcoming ATI modules on neurologic medications.
- Prepare to learn about specific medications, mechanisms, and nursing considerations in the next session.