Animal form and function

the study of the biological form of an organism

the study of the biological functions an organism performs

the way an animal interacts with its environment

genome

shape, size, and environment

reflects different species’ adaptations to a similar environmental challenge

Physical laws impose constraints on animal size and shape

gas exchange

• 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 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)
• The arrangement of epithelial cells may be simple (single cell layer), stratified (multiple tiers of cells), or pseudostratified (a single layer of cells of varying length)

• cuboidal
• columnar
• squamous

• Connective tissue mainly binds and supports other tissues
• It contains sparsely packed cells scattered throughout an extracellular matrix
• The matrix consists of fibers in a liquid, jellylike, or solid foundation

• collagenous fibers
• elastic fibers
• reticular fibers

• Fibroblasts that secrete the protein of extracellular fibers (produce the proteins)
• Macrophages that are involved in the immune system

• 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
• tissue stores fat for insulation and fuel
• is composed of blood cells and cell fragments in blood plasma
• is mineralized and forms the skeleton

• Muscle tissue consists of long cells called muscle fibers, which contract in response to nerve signals
• It is divided in the vertebrate body into three types:
• –skeletal muscle, or striated muscle, is responsible for voluntary movement
• –smooth muscle is responsible for involuntary body activities
• –cardiac muscle is responsible for contraction of the heart

• Nervous tissue senses stimuli and transmits signals throughout the animal
• Nervous tissue contains:
• – neurons, or nerve cells, that transmit nerve impulses
• –glial cells , or glia, that help nourish, insulate, and replenish neurons

Control and coordination within a body depend on the endocrine system and the nervous system

• The endocrine system transmits chemical signals called hormones to receptive cells throughout the body via blood
• A hormone may affect one or more regions throughout the body
• Hormones are relatively slow acting, but can have long-lasting effects

• The nervous system transmits information between specific locations
• The information conveyed depends on a signal’s pathway, not the type of signal
• Nerve signal transmission is very fast
• Nerve impulses can be received by neurons, muscle cells, and endocrine cells