Anatomy and Physiology History

History of Anatomy and Physiology

• Early students of anatomy and physiology were likely focused on treating illnesses and injuries.
• Superstition and magic were initially relied upon for healing.
• Herbs and natural chemicals were later used to treat ailments.
• Early anatomical study included the dissection of cadavers.
• Techniques for accurate observation and experimentation were developed.
• Greek and Latin words are the foundation of anatomical and physiological language.
• The scientific method has been used to gather information to understand the workings of the body.
• An illustration by Andreas Vesalius was made in 1543.

Anatomy and Physiology

• Anatomy is the study of the body's structure (morphology), including its form and organization.
• Physiology is the study of how the body's parts function and interact.
• Anatomy and physiology are closely related, where function depends on structure.
• Anatomists use observation and dissection, while physiologists use experimentation.
• Physiological discoveries are more common, but new anatomical discoveries are still being made.

Levels of Organization

• Cells are the basic structural and functional units of all living things.
• Tissues are groups of cells working together.
• Organs are groups of tissues with specific functions.
• Organ systems are groups of organs working together.
• Organisms have organ systems all functioning and working together.

Characteristics of Life

• Growth is the increase in body size and the number of cells.
• Reproduction is the production of new organisms or cells.
• Responsiveness is the reaction to internal or external changes.
• Movement is a change in the position of the body or its parts, including internal organ motion.
• Metabolism (nutrient cycling) is the sum of all chemical reactions in an organism's cells.
• Respiration is the release of energy from food, using oxygen and producing carbon dioxide.
• Digestion is the breakdown of food into usable forms for absorption into the blood.
• Circulation is the movement of cells and chemicals within body fluids.
• Excretion is the removal of metabolic wastes.

Maintenance of Life

• Water is the most abundant chemical in the body.
• Water is required for many metabolic processes.
• It provides an environment for internal processes.
• Water serves as a transport medium.
• It regulates body temperature.
• Water makes up intracellular and extracellular fluids.
• Heat is a form of energy produced in metabolic reactions.
• Temperature controls the rates of reactions in the body.
• Pressure is a force applied to something.
• Atmospheric pressure is needed for breathing.
• Hydrostatic pressure (fluid pressure) is needed to move blood within blood vessels to deliver oxygen and nutrients.
• Food must supply proper quality and quantity of nutrients.
• Oxygen is needed to release energy from food.

Homeostasis

• The internal environment must remain stable when external factors change.
• Homeostasis is the maintenance of a stable internal environment.
• Homeostasis is regulated with control systems called homeostatic mechanisms.
• Receptors detect and monitor specific types of changes.
• The set point represents the normal value or range of values.
• Effectors are muscles or glands that respond to changes to restore stability.
• Homeostatic mechanisms are self-regulating control systems for maintaining homeostasis.
• The body functions properly when heat, pressure, and concentrations of water, nutrients, and oxygen remain within specific ranges.
• Body temperature regulation occurs similar to that of a thermostat in a home.
• Blood pressure regulation involves pressure-sensitive receptors and muscle cells in blood vessels .
• Receptors monitor deviations from a set point, relaying information about changes in internal conditions (stimuli).
• The set point is the normal value the body tries to maintain for a particular variable.
• The body temperature set point is 98.6°F (37°C).
• Muscle cells or glands (effectors) cause changes to return a variable to its set point.
• Negative feedback is a mechanism that corrects deviations in a variable from its set point.
• It is used in most homeostatic mechanisms.
• Effectors return conditions toward normal when receptors detect deviation.
• The effector activity lessens as the variable returns toward its set point.
• A thermostat is an example of a homeostatic control mechanism with receptors, a set point, and effectors that maintain a normal room temperature.
• Thermoreceptors detect a drop in body temperature.
• Nerve signals are sent to the control center in the brain.
• Blood vessels in the skin constrict to prevent heat loss helping conserve heat.
• Involuntary muscle contractions (shivering) produce body heat.
• Sweat glands become inactive.
• The body warms, and body temperature returns toward normal.
• Thermoreceptors detect a rise in body temperature.
• Nerve signals go to the control center in the brain.
• Sweat glands activate to cool the skin.
• Blood vessels in the skin dilate to lose heat to the environment.
• The digestive system brings nutrients into the body.
• The respiratory system brings in oxygen and releases carbon dioxide.
• The cardiovascular system distributes oxygen and nutrients while removing wastes.
• The urinary and respiratory systems remove wastes from the body.
• Positive feedback is a mechanism by which a variable's deviation from its set point causes conditions to move farther away from the normal state.
• The change increases from the set point.
• Positive feedback causes unstable conditions in the body, but they are short-lived and eventually bring about homeostasis.
• Blood clotting, which stops bleeding is an example.
• Uterine contractions stimulate more contractions during childbirth, leading to the birth of the baby.

Anatomical Terminology

• In the anatomical position, the body is erect, face forward, with upper limbs at the sides and palms forward.
• Terminology is based on the assumption that the body is in an anatomical position.
• Terms of relative position describe the location of body parts in relation to one another.
• Superior means above another part.
• Inferior means below another part.
• Anterior (ventral) means toward the front.
• Posterior (dorsal) means toward the back.
• Medial means closer to the midline when the body is divided into left and right halves.
• Lateral means toward the side, away from the midline.
• Bilateral refers to paired structures, one on each side.
• Ipsilateral refers to structures on the same side of the body.
• Contralateral refers to structures on opposite sides of the body.
• Proximal means closer to the point of attachment to the trunk or another referenced body part.
• Distal means further from the point of attachment to the trunk or another referenced body part.
• Superficial means near the surface or outward.
• Deep means more internal.
• A sagittal section is a longitudinal division into right and left portions.
• A median or midsagittal section divides the body into equal parts along the midline.
• A parasagittal section is lateral to the midline.
• A transverse (horizontal) section divides the body into superior and inferior portions.
• A frontal (coronal) section divides the body into anterior and posterior portions.