Overview of Physiology

Definition: Study of how living organisms function, including physical and biochemical processes.
Branches:
- Cellular Physiology: Focuses on cell functions.
- Organ Physiology: Examines the functions of specific organs.
- System Physiology: Studies systems (e.g., circulatory, respiratory).
- Exercise Physiology: Investigates the body's responses to physical activity.

Homeostasis:
- Maintenance of a stable internal environment despite external changes.
- Involves feedback mechanisms (e.g., negative feedback, positive feedback).
Metabolism:
- Sum of all chemical reactions in the body.
- Divided into:
  - Anabolism: Building up molecules.
  - Catabolism: Breaking down molecules for energy.
Membrane Physiology:
- Cell membranes: Selectively permeable barriers.
- Transport mechanisms:
  - Passive Transport: No energy required (e.g., diffusion, osmosis).
  - Active Transport: Energy required to move substances against a concentration gradient.

Neurons: Electrical signaling units of the nervous system.
Synaptic Transmission: Process by which neurons communicate through neurotransmitters.
Reflex Arc: Pathway that mediates a reflex action, involving sensory input and motor output.

Muscle Types:
- Skeletal Muscle: Voluntary, striated muscle.
- Cardiac Muscle: Involuntary, striated muscle found in the heart.
- Smooth Muscle: Involuntary, non-striated muscle found in organs.
Muscle Contraction:
- Sliding Filament Theory: Actin and myosin filaments slide over each other to contract.

Hormones: Chemical messengers that regulate body functions.
Feedback Loops: Mechanisms that regulate hormone levels (positive and negative feedback).

Heart Function: Pumps blood throughout the body; composed of atria and ventricles.
Circulation Types:
- Systemic Circulation: Supplies blood to the body.
- Pulmonary Circulation: Carries blood to and from the lungs.

Kidney Functions: Filtration of blood, regulation of electrolytes, maintenance of fluid balance.
Nephrons: Functional units of the kidney responsible for urine formation.

Process: Involves ingestion, digestion, absorption, and elimination.
Gastrointestinal Tract: Includes organs like the stomach, intestines, liver, and pancreas.

Male/Female Systems: Involves gametogenesis (spermatogenesis and oogenesis).
Hormonal Regulation: Sex hormones (testosterone, estrogen) play crucial roles in development and functions.

Interaction: Various physiological systems work together to maintain overall homeostasis.
Adaptation: The body adapts functions in response to environmental changes (e.g., altitude, temperature).

Definition: The study of how living organisms function, covering physical and biochemical processes.
Branches:
- Cellular Physiology: Focuses on the functions of individual cells.
- Organ Physiology: Examines the functions of specific organs.
- System Physiology: Studies the functions of organ systems, such as the circulatory or respiratory systems.
- Exercise Physiology: Investigates the body's responses to physical activity.

Homeostasis: The maintenance of a stable internal environment despite external changes.
- Involves feedback mechanisms, such as negative feedback (counteracting a change) and positive feedback (amplifying a change).
Metabolism: The sum of all chemical reactions occurring within the body.
- Divided into:
  - Anabolism: Building up molecules (e.g., protein synthesis).
  - Catabolism: Breaking down molecules for energy (e.g., glucose breakdown).
Membrane Physiology: Cell membranes act as selectively permeable barriers, controlling the movement of substances.
- Transport Mechanisms:
  - Passive Transport: Requires no energy, driven by concentration gradients (e.g., diffusion, osmosis).
  - Active Transport: Requires energy to move substances against their concentration gradients.

Neurons: Specialized cells responsible for electrical signaling in the nervous system.
Synaptic Transmission: The process by which neurons communicate with each other through chemical messengers called neurotransmitters.
Reflex Arc: A neural pathway that mediates a rapid, involuntary response to a stimulus, involving sensory input, processing, and motor output.

Muscle Types:
- Skeletal Muscle: Voluntary, striated muscle responsible for movement.
- Cardiac Muscle: Involuntary, striated muscle that forms the heart.
- Smooth Muscle: Involuntary, non-striated muscle found in the walls of organs.
Muscle Contraction:
- Sliding Filament Theory: Explains muscle contraction as the sliding movement of actin and myosin filaments past each other.

Hormones: Chemical messengers secreted by endocrine glands that regulate various bodily functions.
Feedback Loops: Mechanisms that regulate hormone levels, ensuring proper function.
- Positive Feedback: Amplifies a change (e.g., during childbirth).
- Negative Feedback: Counteracts a change (e.g., regulating blood glucose levels).

Heart Function: Pumps blood throughout the body, consisting of two chambers:
- Atria: Receive blood from the body.
- Ventricles: Pump blood out to the body or lungs.
Circulation Types:
- Systemic Circulation: Delivers oxygenated blood to the body tissues.
- Pulmonary Circulation: Carries deoxygenated blood to the lungs for gas exchange.

Gas Exchange: Occurs in the tiny air sacs called alveoli in the lungs, where oxygen enters the bloodstream and carbon dioxide exits.
Ventilation: The movement of air into and out of the lungs, enabling gas exchange.

Kidney Functions:
- Filtration of blood to remove waste products.
- Regulation of electrolyte balance.
- Maintenance of fluid balance.
Nephrons: Functional units of the kidney responsible for urine formation.

Process: Includes ingestion, digestion, absorption, and elimination of food.
Gastrointestinal Tract: Consists of organs like the stomach, intestines, liver, and pancreas, working together to break down food.

Male/Female Systems: Include organs responsible for gametogenesis (production of gametes):
- Spermatogenesis: Production of sperm in males.
- Oogenesis: Production of eggs in females.
Hormonal Regulation: Sex hormones (testosterone in males, estrogen in females) play crucial roles in development and functions.

Interaction: Different physiological systems collaborate to maintain overall homeostasis.
Adaptation: The body can adapt functions in response to environmental changes (e.g., increased red blood cell production at high altitudes).