Introduction to Physiology and Basic Concepts (Ch. 1–2)

Vocabulary flashcards covering key terms from Chapter 1 (Introduction to Physiology) and basic concepts introduced in Chapter 2 (Molecular Interactions).

Anatomy

The study of body structure and the terminology used to describe it.

Physiology

The science of body functions; study of how the body's parts work and respond to changes.

Levels of Organization

Hierarchy from atoms to organisms: atom → molecule → macromolecule → organelle → cell → tissue → organ → organ system → organism.

Atom

The smallest unit of an element that retains its properties; composed of protons, neutrons, and electrons.

Molecule

Two or more atoms bonded together.

Macromolecule

A large molecule made of many smaller units, such as DNA or proteins.

Organelle

A functional subunit within a cell, e.g., mitochondrion, lysosome.

Cell

The basic unit of life that carries out all life processes.

Tissue

A layer or mass of cells with a specific function (e.g., adipose tissue).

Organ

A structure composed of two or more tissues that performs a coordinated function.

Organ System

A group of organs that work together to perform major functions (e.g., circulatory system).

Organism

An individual living thing made up of organ systems.

Epithelial Tissue

Tissue that protects, secretes, absorbs, and excretes; lines surfaces and forms glands; typically lacks blood vessels and divides rapidly.

Connective Tissue

Binds, supports, and protects; widely distributed; contains extracellular matrix and cells spaced apart.

Muscle Tissue

Responsible for movement; contracts in response to stimuli.

Nervous Tissue

Transmits impulses for coordination, regulation, and sensing; composed of neurons and supporting cells.

Matrix (ECM)

The extracellular material that surrounds cells in connective tissues; made of fibers and ground substance.

Circulatory System

System that transports materials through the body (heart, blood vessels, blood).

Homeostasis

Maintenance of a relatively stable internal environment; dynamic, ongoing readjustment to stay within limits.

Dynamic Steady State

A stable internal condition with continuous movement of materials between compartments, but no net change in the overall load.

Regulated Variable

A variable kept within a normal range by control systems (e.g., pH, oxygen, blood volume).

Control Systems

Local and reflex mechanisms that regulate variables; include input signals, integrating centers, output signals, and effectors.

Local Control

Control restricted to a small region or tissue.

Reflex Control

Long-distance control signaling using nervous and/or endocrine systems.

Input Signal

A stimulus that initiates a response in a control system.

Integrating Center

The part of a control system that processes input signals and determines the appropriate response.

Output Signal

Messages that travel from the integrating center to an effector to produce a response.

Effector

The tissue or organ that carries out the response to adjust the regulated variable.

Teleological Approach

Explanation of function or purpose (“why” a process occurs).

Mechanistic Approach

Explanation of how a process occurs or operates (“how”).

Mass Balance

Law stating steady state: intake plus production minus output equals body load; load remains constant when gains equal losses.

Load

The amount of a substance in the body at a given time.

Excretion

Removal of substances from the body via kidneys, liver, lungs, and skin.

Clearance

The volume of blood cleared of a substance per unit time.

Extracellular Fluid (ECF)

Fluid outside cells; serves as a buffer between the external environment and intracellular fluid.

Intracellular Fluid (ICF)

Fluid contained within cells.

Internal Environment

Fluid environment in which cells reside; essentially the extracellular fluid that surrounds cells.

pH

Negative logarithm of the hydrogen ion concentration; scales from 0 to 14 with 7 as neutral.