Key Concepts in Physiology

Definition: Physiology is the study of the functions and mechanisms in a living system, focusing on how organisms, organ systems, organs, cells, and biomolecules carry out chemical or physical functions.
Branches of Physiology:
- Cell Physiology: Study of cellular processes and interactions.
- Systemic Physiology: Examines the functions of different organ systems (e.g., cardiovascular, respiratory).
- Comparative Physiology: Compares physiological functions across different species.
- Developmental Physiology: Focuses on how physiological functions change throughout life.

Homeostasis: The ability of an organism to maintain a stable internal environment despite external changes.
- Mechanisms include feedback loops (negative and positive), regulatory systems, and signaling pathways.
Metabolism: The sum of all biochemical reactions in the body, including:
- Catabolism: Breakdown of molecules to produce energy.
- Anabolism: Synthesis of complex molecules from simpler ones.
Respiration: The process of gas exchange (oxygen intake and carbon dioxide removal).
- Includes external respiration (lungs) and internal respiration (cellular level).
Circulation: Movement of blood and lymph through the body, involving:
- Heart function (pumping mechanism).
- Blood vessel types (arteries, veins, capillaries).
- Blood components (red blood cells, plasma).
Nervous System Function:
- Central nervous system (CNS) and peripheral nervous system (PNS) roles.
- Transmission of signals through neurons and synapses.
- Reflex arcs and neurotransmitters.
Endocrine System:
- Hormonal regulation of physiological processes.
- Key glands: pituitary, thyroid, adrenal, pancreas.
- Feedback mechanisms (e.g., negative feedback).

Muscular System:
- Types of muscles: Skeletal (voluntary), Cardiac (involuntary), Smooth (involuntary).
- Mechanisms of muscle contraction (sliding filament theory).
Digestive System:
- Processes: Ingestion, digestion, absorption, and excretion.
- Key organs: Stomach, intestines, liver, pancreas.
Immune System:
- Defense against pathogens.
- Components include white blood cells, lymphatic system, and antibodies.
Urinary System:
- Functions in excretion, regulation of blood volume, and electrolyte balance.
- Key organs: Kidneys, ureters, bladder, urethra.

Feedback Mechanisms:
- Negative Feedback: Reduces output or activity when a set point is exceeded (e.g., temperature regulation).
- Positive Feedback: Amplifies processes until a climax event occurs (e.g., childbirth).
Integration of Systems: All physiological systems interact and influence each other, maintaining overall homeostasis.

Techniques: Common physiological research methods include:
- Electrophysiology: Recording electrical activity of cells.
- Imaging techniques: MRI, CT scans for internal structure observation.
- Biochemical assays: Analyzing chemical signals and metabolites.
Applications: Understanding physiology is crucial for medical advancements, disease treatment, and clinical practices.

Physiology encompasses a vast array of topics essential for understanding how living organisms function and adapt. It integrates knowledge from various scientific disciplines and is fundamental to health sciences.

The study of the functions and mechanisms in a living system, focusing on how organisms, organ systems, organs, cells, and biomolecules carry out chemical or physical functions.

Cell Physiology: Study of cellular processes and interactions.
Systemic Physiology: Examines the functions of different organ systems (e.g., cardiovascular, respiratory).
Comparative Physiology: Compares physiological functions across different species.
Developmental Physiology: Focuses on how physiological functions change throughout life.

Homeostasis: The ability of an organism to maintain a stable internal environment despite external changes.
- Mechanisms include feedback loops (negative and positive), regulatory systems, and signaling pathways
Metabolism: The sum of all biochemical reactions in the body.
- Catabolism: Breakdown of molecules to produce energy.
- Anabolism: Synthesis of complex molecules from simpler ones.
Respiration: The process of gas exchange (oxygen intake and carbon dioxide removal).
- Includes external respiration (lungs) and internal respiration (cellular level).
Circulation: Movement of blood and lymph through the body.
- Heart function (pumping mechanism).
- Blood vessel types (arteries, veins, capillaries).
- Blood components (red blood cells, plasma).
Nervous System Function:
- Central nervous system (CNS) and peripheral nervous system (PNS) roles.
- Transmission of signals through neurons and synapses.
- Reflex arcs and neurotransmitters.
Endocrine System:
- Hormonal regulation of physiological processes.
- Key glands: pituitary, thyroid, adrenal, pancreas.
- Feedback mechanisms (e.g., negative feedback).

Muscular System:
- Types of muscles: Skeletal (voluntary), Cardiac (involuntary), Smooth (involuntary).
- Mechanisms of muscle contraction (sliding filament theory).
Digestive System:
- Processes: Ingestion, digestion, absorption, and excretion.
- Key organs: Stomach, intestines, liver, pancreas.
Immune System:
- Defense against pathogens.
- Components include white blood cells, lymphatic system, and antibodies.
Urinary System:
- Functions in excretion, regulation of blood volume, and electrolyte balance.
- Key organs: Kidneys, ureters, bladder, urethra.

Feedback Mechanisms:
- Negative Feedback: Reduces output or activity when a set point is exceeded (e.g., temperature regulation).
- Positive Feedback: Amplifies processes until a climax event occurs (e.g., childbirth).
Integration of Systems: All physiological systems interact and influence each other, maintaining overall homeostasis.

Techniques: Common physiological research methods include:
- Electrophysiology: Recording electrical activity of cells.
- Imaging techniques: MRI, CT scans for internal structure observation.
- Biochemical assays: Analyzing chemical signals and metabolites.
Applications: Understanding physiology is crucial for medical advancements, disease treatment, and clinical practices.

Physiology encompasses a vast array of topics essential for understanding how living organisms function and adapt. It integrates knowledge from various scientific disciplines and is fundamental to health sciences.