Overview
This lecture provides a structured overview of human anatomy and physiology, emphasizing key concepts, organization of the body, and the importance of homeostasis across all organ systems.
Learning Anatomy & Physiology: Foundations
- Anatomy is the study of body structures—what things look like and what they're made of.
- Physiology is the study of body functions—what things do and how they work.
- Structure determines function; knowing anatomy helps predict physiology.
- Use schemas (big idea boxes) to organize and connect concepts rather than studying terms in isolation.
The Central Concept: Homeostasis
- Homeostasis is the body's ability to maintain stable internal conditions (e.g., temperature, blood pH, fluid balance).
- Loss of homeostasis leads to disease; persistent imbalance can be fatal.
- Nearly every cell, organ, and system works to maintain homeostasis.
Levels of Body Organization
- The body is organized hierarchically: atoms → molecules → organelles → cells → tissues → organs → organ systems → organism.
- Organ systems (e.g., cardiovascular, nervous) coordinate to sustain life; individual cells are the functional units.
- DNA in the nucleus encodes proteins that determine cell structure and function (gene expression).
Communication & Regulation: Nervous and Endocrine Systems
- The nervous system (brain, spinal cord, neurons) sends rapid signals (neurotransmitters) to control muscles and respond to stimuli.
- The endocrine system (glands like the pancreas, thyroid) uses hormones (e.g., insulin) in the blood to regulate processes like blood glucose.
- Cells have specific protein receptors to detect these signals and respond.
Acquiring and Maintaining Cellular Needs
- The cardiovascular system delivers oxygen and nutrients; blood circulates to every cell.
- The respiratory system supplies oxygen and removes CO2; the digestive system provides nutrients.
- Cellular respiration uses glucose and oxygen to produce ATP (energy), with CO2 and water as byproducts.
Fluid & Electrolyte Balance: Kidney and Related Systems
- The kidneys filter the blood, reabsorbing useful substances and excreting excess or harmful materials as urine.
- They regulate blood pressure, volume, pH, and electrolyte levels (sodium, potassium).
- The liver neutralizes toxins and manages metabolism; the lymphatic system returns lost fluid to blood and helps with immune defense.
Protection: Skin, Skeleton, and Immunity
- The skin (epidermis, dermis, subcutaneous layer) protects against pathogens, water loss, and temperature extremes.
- Skeletal and muscular systems protect organs and enable movement for defense.
- The immune system and inflammation defend against pathogens and heal injuries.
Reproduction and Genetic Diversity
- Sexual reproduction (meiosis) halves chromosome numbers in sperm and eggs, ensuring offspring have a unique combination of genes.
- Fertilization creates a genetically diverse zygote that develops into a new individual.
Key Terms & Definitions
- Anatomy — study of body structure.
- Physiology — study of body function.
- Homeostasis — maintenance of stable internal environment.
- Neuron — nerve cell receiving and sending signals.
- Gene Expression — process of reading DNA to make specific proteins.
- Neurotransmitter — chemical messenger for nerve signals.
- Hormone — chemical messenger in the blood.
- Cellular Respiration — process of generating ATP using glucose and oxygen.
- Electrolytes — charged ions (e.g., sodium, potassium) essential for function.
- Lymphatic System — system returning fluid to blood and aiding immunity.
- Meiosis — cell division reducing chromosome number for reproduction.
Action Items / Next Steps
- Use schemas to connect new anatomy and physiology concepts in your notes.
- Review the structure and function of the 11 major organ systems.
- Study processes like cellular respiration and how organ systems maintain homeostasis.
- Prepare for deeper dives into each organ system in upcoming classes or assigned readings.