The Animal Body: Basic Form and Function
33.1 Animal Form and Function
Every animal has a distinct body plan, adapted in response to environmental pressures, that limits its size and shape.
Animal body plans can have varying degrees of symmetry and can be described as asymmetrical, bilateral, or radial.
Limits on Animal Size and Shape
Animal shape and body size are influenced by environmental factors as well as the presence of an exoskeleton or an endoskeleton.
Limiting Effects of Diffusion on Size and Development
Less efficient diffusion in larger cells led to multicellular organisms with specialized tissues that supply nutrients and remove waste.
An animal's body size, activity level, and environment impacts the ways it uses and obtains energy.
Animal Body Planes and Cavities
Vertebrates can be divided along different planes in order to reference the locations of defined cavities.
33.2 Animal Primary Tissues
Epithelial tissues cover the outer surfaces of the body and the lumen of internal organs; they are classified by shape and number of layers.
Connective Tissues: Loose, Fibrous, and Cartilage
Connective tissue is found throughout the body, providing support and shock absorption for tissues and bones.
Connective Tissues: Bone, Adipose, and Blood
Bone, adipose (fat) tissue, and blood are different types of connective tissue that are composed of cells surrounded by a matrix.
Muscle Tissues and Nervous Tissues
The function of muscle tissue (smooth, skeletal, and cardiac) is to contract, while nervous tissue is responsible for communication.
Homeostatic processes ensure a constant internal environment by various mechanisms working in combination to maintain set points.
Control of Homeostasis
Homeostasis is typically achieved via negative feedback loops, but can be affected by positive feedback loops, set point alterations, and acclimatization.
Thermoregulation is necessary to ensure maintenance of a homeostatic internal body temperature and can be carried out via various processes.
Heat Conservation and Dissipation
Animals have processes that allow for heat conservation and dissipation in order to maintain a homeostatic internal body temperature.