Anatomy and Physiology: Introduction and Homeostasis

Vocabulary flashcards covering key terms from Lecture 1, including levels of biological organization, tissue types, homeostasis, control systems, and feedback loops.

Anatomy

The study of the form of organisms and their parts.

Physiology

The study of the function of the parts of organisms.

Cells

The smallest biological level of organization that is alive and can survive as a single organism, capable of sensing, responding to its environment, and reproducing.

Epithelia

Tissues consisting of one or more layers of cells in close contact that form borders between other tissues and fluids inside or outside the body.

Connective tissue

Tissue that holds other tissues together, where cells do not touch and are held together by an extracellular matrix.

Muscle tissue

Tissue that contracts to generate motion of the body or of fluids within the body, consisting of smooth, cardiac, and skeletal types.

Nervous tissue

Tissue that sends electrical signals, processes information, and controls the rest of the body.

Organ

A structure made of multiple different tissues in close proximity working together to achieve a function.

Organ Systems

Groups of multiple organs that either have a similar function or work together to achieve a function.

Organism

A biological entity made of multiple organ systems whose parts work together to stay alive.

Homeostasis

An active, energy-requiring process by which an organism maintains stable internal conditions within a narrow range; derived from 'Homeo' (same) and 'stasis' (stand).

Equilibrium

A state in which all parts become equal; non-biological systems tend toward it, but reaching equilibrium in an organism results in death.

Mass balance

The principle that the body must maintain the total amount of each substance, defined by $\text{Change in mass} = \text{Intake} + \text{made by metabolism} - \text{excretion} - \text{lost by metabolism}$.

Control System

A generalized way of describing how the body responds to its environment.

Variable (Control System)

The internal condition that the body wants to maintain, such as temperature or pH.

Setpoint

The specific value at which the body aims to maintain a variable, such as body temperature $\approx 97.3^\circ\text{F}$ or pH $\approx 7.4$.

Receptor

A component of a control system that senses the value of a variable and sends a signal about it to the control center.

Control Center

A component of a control system that receives signals from a receptor, compares the variable value to the setpoint, and sends signals to an effector.

Effector

A component of a control system that receives signals from the control center and takes action to return the variable to the desired range.

Negative feedback

A homeostatic mechanism in which the body responds to a change by moving the variable in the opposite direction to prevent further change.

Positive feedback

A non-homeostatic mechanism in which the body responds to a change by driving the variable further in the same direction, leading to large changes.

Insulin

A hormone released by the pancreas when blood glucose levels are too high, causing the liver to remove glucose from the blood and store it.

Glucagon

A hormone released by the pancreas when blood glucose levels are too low, causing the liver to release stored glucose into the blood.

Oxytocin

A hormone released by the brain during child delivery in response to nervous signals from the cervix, causing the uterus to contract more.