This self-paced, online anatomy and physiology course covers all the bodily systems playing a major role in human anatomy. The material is presented in a practical and comprehensive manner. The focus of the course is on the need-to-know facts that must be understood in order to pursue any healthcare career or related education in the field of science. These easy to follow lessons are ideal for anyone requiring a solid understanding of how the human body works.
Anatomy, which is sometimes called morphology, provides a map of how a body is put together, human or otherwise.
Physiology is akin to an instruction manual. Form and function must both be considered to fully understand the human body.
Physiology is the study of living things, but what exactly does it mean to be alive? It is difficult to isolate a single characteristic that separates all living entities from non-living ones. For example, some might say the ability to reproduce is a necessary trait to indicate life. But mules--which are definitely living offsprings of a horse and donkey--cannot reproduce. So physiologists consider a number of traits that all living things have in common and thus identify life based on the following characteristics:
- Absorption: the passage of nutrients from digested food through membranes and into body fluids
- Assimilation: the ability to change nutrients of absorbed substances into chemically different forms
- Circulation: movement of substances throughout the body via body fluids such as blood
- Digestion: chemically breaking down food into its molecular components and getting rid of wastes
- Growth: in general, defined as increasing in size without changing basic shape
- Movement: the ability to change position or internal structures
- Reproduction: creating offspring
- Respiration: can mean the act of breathing but on a cellular level; it's a metabolic process that uses oxygen to release energy from glucose
- Responsiveness: reacting to one's environment, such as pupils contracting in light, the rush of adrenalin when confronted with danger or fear, or a plant bending toward sunlight
- Excretion: the removal of wastes created by metabolic activity
Everything that is alive--from cells to elephants--relies on homeostasis, which is the way the physiological systems work together in living organisms to maintain a stable internal environment, despite changing external or environmental conditions. In humans, that means regulating things like temperature, pH, hydration, and blood oxygen levels.
All living things also require some sort of metabolism, which is commonly understood to mean breaking food down and turning it into energy. But in physiological terms, it refers to the entire range of an organism's biochemical processes. These metabolic pathways involve enzymes that transform one substance into another substance, by either breaking one down (catabolism) or creating a new one (anabolism).
Levels of Anatomical Organization
Anatomists organize the human body into different levels, each level increasing in complexity.
- Atoms join together to form molecules, such as H2O.
- Molecules combine to form macromolecules such as polysaccharides (complex carbohydrates), monosaccharides (simple sugars), and fats (lipids).
- Macromolecules combine to create organelles like mitochondrion and ribosomes.
- Organelles are part of a cell, the basic unit of a body.
- Cells are organized into tissues such as muscle, neural, and cardiac.
- Tissues are organized into organs, from the brain to the large intestine and everything in between.
- Organs working together are organ systems, which include the digestive system, the endocrine system, and the nervous system.
- Organ systems make up an organism, such as humans, dogs, or plants.