Pharm Week 2 Class Notes #2

Overview of the Nervous System

• The nervous system is crucial for communication and control within the body.

• Main components: Brain and Spinal Cord (Central Nervous System)

Peripheral Nervous System (PNS)

• Connects CNS to the rest of the body via cranial and spinal nerves.

• Acts as a communication pathway or middleman, transmitting signals.

Motor Division of PNS

• Responsible for connecting impulses from the CNS to muscles and glands.

• Operates continuously while engaging in various activities (e.g., moving hands, walking).

Divisions of the Motor Division

• Somatic Nervous System (Voluntary Control)

• Controls voluntary muscle movements (e.g., pressing a button).

• Conscious and purposeful actions.

• Autonomic Nervous System (Involuntary Control)

• Manages involuntary functions, affecting:

  • Heart rate

  • Blood pressure

  • Respiratory rate

  • Gland functions (e.g., sweating, pupil dilation).

Sensory Division

• Involves sensory signals that allow for perception.

• Important in taste, smell, sight, and hearing.

Autonomic Nervous System Subdivisions

• Sympathetic Division (Fight or Flight)

• Triggers increased heart rate, blood pressure, and respiratory rate during stress or emergencies.

• Represents the body’s active response to fear or excitement.

• Parasympathetic Division (Rest and Digest)

  • Conserves energy and promotes restorative functions (e.g., digestion).

  • Controls body at rest, leading to decreased heart rate and blood pressure.

Importance of Balance between Divisions

• Essential for mental health; issues arise if one system dominates too much over the other.

• Both divisions must work together to maintain homeostasis.

Neurotransmitters in the Autonomic Nervous System

• Sympathetic Nervous System

• Presynaptic neurotransmitter: Acetylcholine

• Postsynaptic neurotransmitter: Norepinephrine

• Receptors: Alpha (affects blood vessels) and Beta (affects heart and lungs).

  • Beta 1 receptors: Increase heart function and rate.

  • **Beta