Pharmacology for Nursing - Topic 3: Physiology Concepts

Introduction

• Lecturer: Professor Jim Hoffman
• Topic: Physiology Concepts for Nursing Pharmacology
• Learning Objectives: Autonomic nervous system, Renin-angiotensin-aldosterone system, and Inflammatory process
• Resources: Online text with hyperlinks to 4.2, 6.2, 10.2 sections

Importance of Basic Anatomy and Physiology

• Essential for understanding medications and pharmacodynamics
• Definition: Pharmacodynamics - effects of drugs on the body
• Key drug responses:
  • Mimic/Stabilize normal functions
  • Inhibit/Block normal activities

Autonomic Nervous System (ANS)

Overview

• Divisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS)
• Components of the PNS:
  • Motor (outgoing messages)
  • Sensory (incoming messages) to CNS
• Motor Division: Somatic (voluntary) and Autonomic (involuntary)

Autonomic Nervous System Details

• Sympathetic Nervous System (SNS): Fight or Flight
  • Chemicals: Norepinephrine, Epinephrine, Dopamine, Serotonin (Catecholamines)
  • Receptor Sites: Alpha-1, Alpha-2, Beta-1, Beta-2
• Parasympathetic Nervous System (PNS): Rest and Digest
  • Chemical: Acetylcholine
  • Receptor Sites: Nicotinic, Muscarinic

Drug Actions in the ANS

• Agonists: Drugs that stimulate/mimic normal physiological functions
• Antagonists: Drugs that block normal physiological functions

Key Concepts

• Sympathetic (Adrenergic) vs. Parasympathetic (Cholinergic)
  • Stimulating SNS: Pupil dilation, Inhibited secretions, Accelerated heart rate, Bronchodilation, Increased glucose production, Secretion of adrenaline, Urinary retention
  • Stimulating PNS: Pupil constriction, Facilitated secretions, Slowed heart rate, Bronchoconstriction, Stimulated bile release, Increased urination
• Receptor Site Impacts:
  • Parasympathetic: Less selectivity (Muscarinic)
  • Sympathetic: Higher selectivity (Alpha and Beta receptors)

Renin-Angiotensin-Aldosterone System (RAAS)

Basic Components

• Maintains fluid and blood pressure homeostasis
• Key Players: Renin, Angiotensinogen, Angiotensin 1, Angiotensin 2, Aldosterone
• Process:
  • Kidneys release renin in response to low fluid/Sodium
  • Renin + Angiotensinogen → Angiotensin 1
  • Angiotensin 1 + ACE (from pulmonary circulation) → Angiotensin 2
  • Angiotensin 2 Effects: Widespread vasoconstriction, Stimulates adrenal cortex to release aldosterone
  • Aldosterone → Retains sodium and water, increasing blood volume and pressure

Key Concepts

• Neural Response: Sympathetic activation, release of epinephrine/norepinephrine, rapid vasoconstriction, and rise in heart rate
• Hormonal Response: RAAS activation, angiotensin 2 effects, and aldosterone-mediated fluid retention
• Integration: Sympathetic nervous system's short-term response works with RAAS for prolonged responses

Inflammatory Response

Overview

• Role: Body’s response to tissue injury
• Components: Increased permeability, blood flow, mediator chemicals (e.g., prostaglandin), sensitivity of pain receptors
• Drugs: Anti-inflammatories (NSAIDs, Steroids), Immunosuppressants
• Key Concepts:
  • Anti-inflammatory drugs manage pain by blocking or inhibiting parts of the natural inflammatory response
  • Importance of understanding potential ramifications of interrupting normal physiological responses

Final Notes

• Importance of integrating pharmacology with anatomy, physiology, and pathophysiology
• Review key systems and their drug interactions:
  • Autonomic Nervous System
  • Renin-Angiotensin-Aldosterone System
  • Inflammatory Response
• Understanding physiology concepts aids in comprehending pharmacodynamics of medications