Introduction to Physiology

Introduction to Physiology

• Physiology is the study of how living organisms function.
• It encompasses a wide range of topics, from the molecular level to the organismal level.
• Physiological processes are vital for survival and involve complex interactions among biological systems.
• Key areas of study include:
  • Cellular physiology, focusing on the functions of individual cells.
  • Systems physiology, examining how different organ systems work together.
  • Organismal physiology, investigating the overall function of a whole organism.

Key Concepts in Physiology

• Homeostasis: Maintaining a stable internal environment despite external fluctuations.
  • Examples include regulating body temperature, blood glucose levels, and blood pressure.
  • Homeostatic mechanisms control these critical parameters.
• Feedback loops: Essential for homeostasis.
  • Negative feedback loops counteract deviations from a set point, restoring equilibrium.
  • Positive feedback loops amplify changes, leading to a rapid response, such as blood clotting.
• Cell Signaling: Crucial cellular communication.
  • Signaling pathways involve molecules like hormones, neurotransmitters, and local mediators.
  • These signals trigger cascades of cellular events.
• Membrane transport: Essential for cellular function.
  • Active and passive transport mechanisms regulate the movement of ions and nutrients across cell membranes.

Specialized Areas of Physiology

• Cardiovascular physiology: Studying the heart, blood vessels, and blood circulation, including blood flow, pressure, and circulation patterns.
• Respiratory physiology: Examining the respiratory system's role in gas exchange (oxygen and carbon dioxide) between the body and the environment.
• Renal physiology: Investigating the kidney's function in filtering blood, regulating electrolyte balance, and producing urine.
• Neurophysiology: Studying the nervous system, including nerve impulses, synaptic transmission, and brain function.

Cellular Physiology

• Cell membrane structure and function: Maintaining the internal cellular environment and facilitating external communication.
  • Cell membranes are selectively permeable, controlling substance passage.
• Cellular Metabolism: Chemical reactions that build and break down molecules for energy.
  • Anabolism and catabolism are key metabolic processes.
  • Enzymes catalyze these reactions.
• Cellular Respiration: Energy production within cells.
• Cell signaling mechanisms: Intra- and intercellular communication.

Systems Physiology

• Digestive physiology: Processing food to absorb nutrients.
• Musculoskeletal physiology: Skeletal and muscular systems in movement, support, and protection.
• Endocrine physiology: Hormone production and function.
• Immune physiology: Body's defense mechanisms against infection.

Factors Influencing Physiological Processes

• Genetics: Individual's genetic makeup affects physiological traits.
• Environment: External factors (temperature, altitude, diet) influence physiological processes.
• Age: Physiological functions change throughout life.
• Disease: Pathologies impact physiological processes.