Basic Principles of Animal Form and Function Levels

Basic Principles of Animal Form and Function Levels of Structural Organization Body plan and External Environment Regulating the Internal Environment

Levels of Structural Organization • Hierarchy of multicellular organisms • Cell tissue organ system

Organ Systems • • • Integumentary Skeletal Muscular Digestive Nervous Circulatory • • • Respiratory Immune/Lymphatic Excretory Endocrine Reproductive

Tissue Groups of cells with common structure and Function, four types: • Epithelial • Connective • Nervous • Muscle

Epithelial Tissue • Tightly packed • Lines organs and body cavities, covers the body • Classified by shape and by number of layers

Connective Tissue • Characterized by a sparse cell population scattered through an extensive extracellular matrix • Major types: loose connective, adipose, fibrous connective, cartilage, bone, blood

Nervous Tissue • Senses stimuli and transmits signals from one part of the animal to another • Neurons – nerve cells

Muscle Tissue • Consists of long excitable cells capable of contraction • Most abundant tissue in animals • Three types: skeletal, smooth, and cardiac

Regulating the Internal Environment • Interstitial fluid-composed of fluid between the cells of vertebrates • Homeostasis-dynamic state of equilibrium in which internal conditions remain relatively stable; “steady state”

Thermoregulation • Adjust rate of exchange between animal and it’s environment • vasodilation • vasoconstriction • countercurrent heat exchange • evaporative heat loss • behavioral responses • rate of metabolic heat production

Regulation of Body Temperature • Heat gain or loss in organisms results from: conduction, convection, radiation, and evaporation • Ectotherms: absorb heat from the environment, most invertebrates, fishes, reptiles, and amphibians • Endotherms: derives most of their heat from metabolism, mammals, birds, some fish, and numerous insects

Ectothermy • Body orientation to the sun (locust) • social organization (honeybees)

Endothermy • Ability to regulate metabolism • Humans and other terrestrial mammals utilize hypothalamus • Feedback through nervous system results in vasodilation or vasoconstriction to skin vessels

Counter Current Heat Exchange

Heat Shock Proteins • Found in animal cells, yeast, and bacteria • cells are able to make RAPID adjustments to temperature changes • prevent denaturation • produced by heat-shock genes

Torpor during Environmental Extremes • Hibernation • Estivation • Daily torpor (diurnal vs nocturnal)