Comprehensive Anatomy & Physiology Study Guide: Key Terms and Concepts

Anatomy & Physiology: Foundational Concepts

Introduction to Anatomy and Physiology

Anatomy and Physiology are closely related fields that study the structure and function of the human body. Understanding key terms is essential for mastering the subject.

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of body parts and how they work to carry out life-sustaining activities.

• Homeostasis: The maintenance of a stable internal environment despite changes in external conditions.

• Levels of Organization: Chemical, cellular, tissue, organ, organ system, organism.

• Metabolism: All chemical reactions that occur within the body.

• Negative Feedback: A mechanism that reverses a deviation from the set point; most homeostatic control mechanisms.

• Positive Feedback: A mechanism that amplifies a change; less common in the body.

The Chemical Level of Organization

Atoms, Molecules, and Chemical Bonds

The chemical level forms the foundation for all biological processes. Understanding atoms, molecules, and chemical bonds is crucial for grasping cellular function.

• Atom: The smallest unit of matter that retains the properties of an element.

• Molecule: Two or more atoms bonded together.

• Ionic Bond: Formed when electrons are transferred from one atom to another.

• Covalent Bond: Formed when atoms share electrons.

• Hydrogen Bond: A weak bond between two molecules resulting from an electrostatic attraction.

• pH: A measure of hydrogen ion concentration; scale ranges from 0 (acidic) to 14 (basic).

The Cellular Level of Organization

Cell Structure and Function

Cells are the basic units of life. Each cell contains organelles that perform specific functions necessary for survival.

• Cell Membrane: A phospholipid bilayer that surrounds the cell and regulates what enters and leaves.

• Nucleus: Contains genetic material (DNA) and controls cellular activities.

• Mitochondria: The site of ATP production; known as the "powerhouse" of the cell.

• Ribosomes: Sites of protein synthesis.

• Endoplasmic Reticulum (ER): Rough ER synthesizes proteins; Smooth ER synthesizes lipids.

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or use within the cell.

• Lysosomes: Contain digestive enzymes to break down waste.

The Tissue Level of Organization

Types of Tissues

Tissues are groups of similar cells that perform a common function. There are four basic types of tissues in the human body.

• Epithelial Tissue: Covers body surfaces and lines cavities.

• Connective Tissue: Supports, protects, and binds other tissues together.

• Muscle Tissue: Responsible for movement.

• Nervous Tissue: Transmits electrical impulses for communication.

The Integumentary System

Structure and Function

The integumentary system includes the skin, hair, nails, and glands. It protects the body and helps regulate temperature.

• Epidermis: The outermost layer of skin; provides a waterproof barrier.

• Dermis: Beneath the epidermis; contains connective tissue, hair follicles, and sweat glands.

• Hypodermis: Subcutaneous layer; stores fat and anchors skin to underlying tissues.

• Melanin: Pigment that gives skin its color.

Bones and Bone Structure

Classification and Anatomy of Bones

Bones provide support, protection, and enable movement. They are classified by shape and structure.

• Long Bones: Longer than they are wide (e.g., femur).

• Short Bones: Cube-shaped (e.g., carpals).

• Flat Bones: Thin and broad (e.g., skull).

• Irregular Bones: Complex shapes (e.g., vertebrae).

• Osteon: Structural unit of compact bone.

• Osteocyte: Mature bone cell.

• Osteoblast: Bone-forming cell.

• Osteoclast: Bone-resorbing cell.

The Axial and Appendicular Skeleton

Major Divisions of the Skeleton

The human skeleton is divided into axial and appendicular components, each with distinct functions.

• Axial Skeleton: Skull, vertebral column, and thoracic cage.

• Appendicular Skeleton: Limbs and girdles (shoulder and pelvic).

Joints

Classification and Function

Joints, or articulations, connect bones and allow for movement.

• Fibrous Joints: Immovable (e.g., sutures in the skull).

• Cartilaginous Joints: Slightly movable (e.g., intervertebral discs).

• Synovial Joints: Freely movable (e.g., knee, shoulder).

Muscle Tissue and the Muscular System

Types and Functions of Muscle Tissue

Muscle tissue is specialized for contraction and movement. There are three types of muscle tissue.

• Skeletal Muscle: Voluntary movement; attached to bones.

• Cardiac Muscle: Involuntary; found only in the heart.

• Smooth Muscle: Involuntary; found in walls of hollow organs.

• Actin and Myosin: Protein filaments responsible for muscle contraction.

Nervous Tissue and the Nervous System

Structure and Function

The nervous system coordinates body activities through electrical and chemical signals.

• Neuron: Nerve cell; transmits electrical impulses.

• Neuroglia: Support cells in the nervous system.

• Central Nervous System (CNS): Brain and spinal cord.

• Peripheral Nervous System (PNS): All nerves outside the CNS.

The Endocrine System

Hormones and Glands

The endocrine system regulates body functions through hormones secreted by glands.

• Hormone: Chemical messenger released into the bloodstream.

• Pituitary Gland: The "master gland"; regulates other endocrine glands.

• Thyroid Gland: Regulates metabolism.

• Adrenal Glands: Produce hormones involved in stress response.

Blood and the Cardiovascular System

Components and Functions of Blood

Blood transports nutrients, gases, and wastes. The cardiovascular system circulates blood throughout the body.

• Red Blood Cells (Erythrocytes): Carry oxygen.

• White Blood Cells (Leukocytes): Defend against infection.

• Platelets (Thrombocytes): Involved in blood clotting.

• Heart: Pumps blood through the circulatory system.

• Arteries: Carry blood away from the heart.

• Veins: Carry blood toward the heart.

• Capillaries: Exchange of substances between blood and tissues.

The Lymphatic System and Immunity

Defense Mechanisms

The lymphatic system helps defend the body against pathogens and maintains fluid balance.

• Lymph: Fluid that circulates in the lymphatic system.

• Lymph Nodes: Filter lymph and house immune cells.

• Immunity: The ability to resist infection.

The Respiratory System

Gas Exchange and Regulation

The respiratory system supplies oxygen and removes carbon dioxide from the body.

• Lungs: Main organs of respiration.

• Alveoli: Tiny air sacs where gas exchange occurs.

• Diaphragm: Muscle that aids in breathing.

The Digestive System

Structure and Function

The digestive system breaks down food, absorbs nutrients, and eliminates waste.

• Mouth: Begins mechanical and chemical digestion.

• Esophagus: Transports food to the stomach.

• Stomach: Mixes and digests food.

• Small Intestine: Main site of nutrient absorption.

• Large Intestine: Absorbs water and forms feces.

Metabolism, Nutrition, and Energetics

Energy Production and Nutrient Utilization

Metabolism encompasses all chemical reactions in the body, including those that produce energy from nutrients.

• Anabolism: Building up of complex molecules from simpler ones.

• Catabolism: Breaking down of complex molecules to release energy.

• ATP (Adenosine Triphosphate): The main energy currency of the cell.

The Urinary System

Excretion and Fluid Balance

The urinary system removes waste products and regulates fluid and electrolyte balance.

• Kidneys: Filter blood and produce urine.

• Ureters: Transport urine from kidneys to bladder.

• Bladder: Stores urine.

• Urethra: Conducts urine out of the body.

Fluids & Electrolytes

Regulation and Balance

Maintaining proper fluid and electrolyte balance is essential for normal cellular function.

• Electrolytes: Ions that help regulate nerve and muscle function.

• Osmosis: Movement of water across a semipermeable membrane.

• Dehydration: Loss of water from the body.

The Reproductive System

Structure and Function

The reproductive system enables the production of offspring and the continuation of genetic material.

• Testes: Male gonads; produce sperm and testosterone.

• Ovaries: Female gonads; produce eggs and estrogen.

• Uterus: Site of fetal development.

• Menstrual Cycle: Regular changes in the female reproductive system.

Development and Inheritance

Genetics and Embryology

Development and inheritance cover the processes from fertilization to birth and the transmission of genetic traits.

• Fertilization: Union of sperm and egg.

• Embryo: Early stage of development.

• Gene: Unit of heredity; segment of DNA.

• Chromosome: Structure containing genetic material.