Cell and Organ System Physiology

Physiology

• Physiology is the study of how living organisms function.
• It encompasses a broad range of processes, from cellular functions to the workings of entire organ systems.

Cellular Physiology

• Cells are the basic units of life, and their individual functions are crucial to overall organismal function.
• Cellular physiology examines the chemical and physical processes within cells.
• These processes include membrane transport mechanisms (diffusion, osmosis, active transport), energy production (cellular respiration), protein synthesis and degradation, and cell signaling and communication.
• These processes are essential for cells to maintain homeostasis (internal stability) and respond to external stimuli.

Organ System Physiology

• This examines the integrated functioning of various organ systems, including:
  • Nervous system (neurons, synapses, nerve impulse transmission).
  • Cardiovascular system (blood circulation, heart function, blood pressure regulation).
  • Respiratory system (gas exchange, breathing mechanics).
  • Digestive system (food breakdown, nutrient absorption).
  • Urinary system (waste removal, water balance).
  • Endocrine system (hormone production and action).
  • Musculoskeletal system (muscle contraction, skeletal function).
• The interactions between these systems are complex, such as the nervous system interacting with the cardiovascular system to regulate heart rate and blood pressure.

Homeostasis

• Homeostasis is the maintenance of a stable internal environment despite external changes.
• It is critical for proper functioning of cells and organs.
• Physiological mechanisms regulate factors like body temperature, blood glucose levels, blood pH, and water balance.
• Feedback loops maintain homeostasis through continuous monitoring and adjustment.

Nervous System Function

• The nervous system coordinates and regulates body activities.
• Sensory neurons receive stimuli and transmit information to the brain and spinal cord.
• Motor neurons transmit signals from the central nervous system to muscles and glands.
• Interneurons connect sensory and motor neurons and process information.
• Neurotransmitters are chemical messengers carrying signals between neurons.

Cardiovascular System Function

• The cardiovascular system circulates blood.
• The heart pumps blood carrying oxygen, nutrients, and hormones to tissues.
• Blood carries away waste products.
• Blood vessels (arteries, veins, capillaries) are vital for blood transport.

Respiratory System Function

• The respiratory system facilitates gas exchange (oxygen and carbon dioxide).
• Lungs are the primary breathing organs.
• Breathing involves inspiration and expiration.
• Gas exchange occurs in the alveoli of the lungs.

Digestive System Function

• This system breaks down food into absorbable molecules.
• Digestion involves mechanical and chemical processes.
• Nutrients are absorbed into the bloodstream.
• Waste products are eliminated.

Urinary System Function

• The urinary system removes waste and maintains fluid and electrolyte balance.
• Kidneys filter blood and produce urine.
• Urine travels from kidneys to the bladder and is excreted.
• This system maintains internal salt and water balance.

Endocrine System Function

• The endocrine system regulates body functions via hormones.
• Hormones are chemical messengers affecting target cells or organs.
• Different hormones have various effects, such as regulating growth, metabolism, and reproduction.
• Hormone interaction is essential for maintaining a stable internal environment.