Basic Principles of Animal Form and Function

• Anatomy is the study of the biological form of

  an organism.
• Physiology is the study of the biological functions an organism performs.
• The comparative study of animals reveals that form and function are closely correlated.
• Size and shape affect the way an animal interacts with its environment.
• Many different animal body plans have evolved and are determined by the genome.
• The ability to perform certain actions depends on an animal’s shape, size, and environment.
• Evolutionary convergence reflects different species’ adaptations to a similar environmental challenge.
• Physical laws impose constraints on animal size and shape.
• An animal’s size and shape directly affect how it exchanges energy and materials with its surroundings.
• Exchange occurs as substances dissolved in the aqueous medium diffuse and are transported across the cells’ plasma membranes.
• A single-celled protist living in water has a sufficient surface area of plasma membrane to service its entire volume of cytoplasm.
• Multicellular organisms with a sac body plan have body walls that are only two cells thick, facilitating diffusion of materials.
• More complex organisms have highly folded internal surfaces for exchanging materials.
• In vertebrates, the space between cells is filled with interstitial fluid, which allows for the movement of material into and out of cells.
• A complex body plan helps an animal in a variable environment to maintain a relatively stable internal environment.
• Most animals are composed of specialized cells organized into tissues that have different functions.
• Tissues make up organs, which together make up organ systems.
• Different tissues have different structures that are suited to their functions.
• Tissues are classified into four main categories: epithelial, connective, muscle, and nervous.
• Epithelial Tissue - Covering & Lining
• Epithelial tissue covers the outside of the body and lines the organs and cavities within the body. It contains cells that are closely joined.
• The shape of epithelial cells may be cuboidal (like dice), columnar (like bricks on end), or squamous (like floor tiles).
• Connective tissue mainly binds and supports other tissues.
• Connective Tissue


  It contains sparsely packed cells scattered throughout an extracellular matrix.
• Connective Tissue


  The matrix consists of fibers in a liquid, jellylike, or solid foundation.
• There are three types of connective tissue fiber, all made of protein: Collagenous fibers, Elastic fibers, Reticular fibers
• Collagenous fibers provide strength and flexibility.
• Elastic fibers stretch and snap back to their original length.
• Reticular fibers join connective tissue to adjacent tissues.
• In vertebrates, the fibers and foundation combine to form six major types of connective tissue: Loose connective tissue, Cartilage, Fibrous connective tissue, Adipose tissue, Blood, Bone
• Loose connective tissue binds epithelia to underlying tissues and holds organs in place.
• Cartilage is a strong and flexible support material.
• Fibrous connective tissue is found in tendons, which attach muscles to bones, and ligaments, which connect bones at joints.
• Adipose tissue stores fat for insulation and fuel.
• Blood is composed of blood cells and cell fragments in blood plasma.
• Bone is mineralized and forms the skeleton.
• Muscle tissue consists of long cells called muscle fibers, which contract in response to nerve signals.
• Muscle tissues is divided in the vertebrate body into three types: Skeletal muscle, Smooth muscle, Cardiac muscle
• Skeletal muscle, or striated muscle, is attached to bones and is responsible for voluntary movement.
• Smooth muscle mainly lines internal organs and is responsible for involuntary body activities.