Anatomy biological form o Provides clues to physiology Chapter 40 Basic Principles of Animal form and Function Physiology biological function Why do species vary so much adaption and natural selection Animal size and shape o Limited by strength diffusion movement and heat exchange Form and Function Water limits shape of fast swimmers in water o As size increases thicker skeletons are required Muscles must take up more body mass At some point mobility becomes limited Exchange with the environment o Requirement to exchange with environment puts another restraint on animals o Rate of exchange is proportional to the membrane surface area Animals with simple internal organization Hydra saclike body plan and body wall only 2 cell layers thick Tape worm flat thin shape no digestive system Multicellular animal must have adequate exchange for every cell Have digestive respiratory and circulatory exchange surfaces o Exchange surfaces Interstitial fluid fluid that fills the spaces between cells Exchange between circulatory fluid nutrients for wastes o Benefits of a complex body plan Skeleton protects against predators Sensory organs provide info about the environment Digestive system controls release of energy Can maintain internal environment Especially important for land animals as they aren t bathed in liquid Hierarchical organization of body plans o Cells smallest unit of life o Tissue group of cells with similar appearance and common function o Organ collection of tissues organized into functional units o Organ system group of organs that work together Some organs can belong to more than 1 system pancreas is involved in digestion and endocrine signaling 4 types of tissues Epithelial tissues epithelium cover membrane surfaces and line organs cavities o Sheets of cells bound by tight junctions o Provide a barrier to injury pathogens and water loss o 5 types of epithelium Cuboidal epithelium dice shaped cells used for secretion Epithelium of kidney tubules and glands Simple columnar epithelium brick shaped cells used for secretion and absorption Lines intestines Simple squamous epithelium 1 layer of plate like cells used for exchange of materials by diffusion Thin and leaky Lines blood vessels and air sacs in lungs Stratified squamous epithelium multilayered and regenerative New cells formed by division near the basal lamina and push outward to replace cells that are sloughed off Surfaces subject to abrasion Pseudo stratified columnar epithelium 1 layer of cells of varying height Ciliated in mucus membrane lining of the stomach o Epithelium is polarized Apical surface faces the lumen cavity outside and is exposed to fluid air Microvilli increase surface area of apical surface Basal surface attached to the base Basal lamina dense mat of ECM separating epithelium from the underlying tissue Connective tissue cells scattered in ECM holds tissues and organs together in place volume of cells ECM o Matrix generally made of fibers in a liquid jelly or solid foundation o Fibroblasts secrete fiber proteins o Macrophages engulf foreign particles and cell debris o 3 fiber types Collagenous strength and flexibility Mostly collagen Reticular join connective tissue to tissues Elastic makes tissues elastic o Loose connective binds epithelia to tissue and holds organs in place Most widespread All 3 fiber types loosely woven together In skin and throughout body o Fibrous connective tissue dense with collagenous fibers Tendons muscles to bones Ligaments bones to bones and joints o Bone mineralized connective tissue Osteoblasts make bone by depositing collagen matrix Calcium magnesium and phosphate ions Osteons concentric layers of mineralized matrix around a central canal of blood vessels and nerves repeating units Make up skeleton o Blood carries nutrients and wastes to and from cells Plasma liquid extracellular matrix Water salt and proteins Erythrocytes red blood cells that carry oxygen Leukocytes white blood cells for dense o Cartilage collagenous fibers in rubbery protein carbohydrate complex called chondroitin sulfate Chondrocytes secrete collagen and chondroitin sulfate Strong and flexible Skeleton of embryos are made of cartilage this is replaced by bone o Adipose specialized loose connective tissues that store fat in adipose cells Protects and insulates Stores fuel as fat Adipose cells contain a large fat droplet Muscle tissue responsible for movement o Filaments of actin an myosin o Skeletal striated muscle voluntary movements Bundles of long cells called muscle fibers Multiple nuclei Form by fusion of many cells Sarcomeres contractile unit o Smooth walls of digestive tract urinary bladder and internal organs Not striated Spindle shaped Involuntary o Cardiac contractile wall of heart Striated Muscle cells interconnected by intercalated discs Relay signals from cell to cell and sarcomere heart function Nervous tissue nerve cells transmit impulses o Received info from dendrites o Axons send signals o Glial cells support cells and nourish insulate and replenish neurons Skin is an organ Endocrine signaling o Made of epidermis dermis hypodermis and adipose layers Coordination and Control 2 major signaling systems o Hormones signaling molecules released into blood Only cells with receptors respond Slow acting and long lasting o Good for coordinating gradual changes that effect the entire body Growth development Reproduction Metabolic processes Digestion Nervous system nerve impulses o Targeted and sent along specific communication lines 4 types of cells receive impulses Other neurons Muscle cells Endocrine cells Exocrine cells o Travel along axons by changes in voltage o Between neurons by short range neurotransmitters o Rapid and short o Good for immediate and rapid responses to the environment Feedback Control Maintains Internal Environment Regulating and conforming o Regulator animal that uses internal mechanisms to control change in the face of o Conformer animal that allows internal environment to change with external external fluctuation environment Homeostasis maintenance of internal balance Maintaining homeostasis o Set point a particular value that an animal maintains a variable at o Stimulus fluctuations in the variable o Sensor detects a stimulus and sends to control center to trigger a response o Response physiological activity that helps return variables to the set point Feedback control o Negative feedback reduces stimulus Adaptations that reduce fluctuation Insulation for temperature
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