Presentation on theme: "Chapter 40: Basic Principles of Animal Form and Function"— Presentation transcript:
1Chapter 40: Basic Principles of Animal Form and Function Periods 3-4
2Animal Form and Function are Correlated at all Levels of Organization Anatomy: the structure of an organism and its studyPhysiology: the processes and functions of an organism and their studyPhysical constraints on animal size and shapePhysics laws govern strength, diffusion, movement, and heat exchangeNatural selection often shapes similar adaptations when diverse organisms face similar environmental challenges (convergent evolution)Ex: body shape of fast swimmersPhysics influences the maximum size of animalsAs body dimensions increase, thicker skeletons are required to maintain strengthAs body size increases, more muscle is required for locomotionExchange with the EnvironmentEach cell of an animal must have access to an aqueousenvironmentTwo layered sacs and flat shapes maximize exposure to thesurrounding environmentInterstitial fluid: fluid filling the spaces between animal cellsComplex body plans also have a circulatory fluid (blood)Exchange between interstitial fluid and circulatory fluidenables cells to obtain nutrients and get rid of wastes
3Hierarchical Organization of Body Plans Organ System: a group of organs that work together to perform vital body functionsOrgan: a specialized center of body function composed of several different types of tissuesTissue: an integrated group of cells with a common function, structure, or both1. Epithelial Tissue: sheets of tightly packed cells that line organs and body cavities as well as external surfaces2. Connective Tissue: tissue that functions mainly to bind and support other tissues, having a sparse population of cells scattered through an extracellular matrixCollagenous Fibers: made of collagen (protein); provide strength combined with flexibility; nonelastic and do not tear easily when pulled lengthwiseElastic Fibers: long threads made of elastin (protein); easily stretched but are also resilient, snapping back to original length when tension is releasedReticular Fibers: made of collagen and continuous with collgenous fibers; form a tightly woven fabric that joins connective tissue to adjacent tissues3. Muscle Tissue: long muscle cells that can contract on its own or when stimulated by nerve impulses4. Nervous Tissue: tissues made up of neurons and supportive cells
4Animal Tissues 1. Epithelial Tissue The close packing (tight junctions) enables the tissue to function as a barrierEpithelium: the cells of epithelial tissue, which form active interfaces with the environmentCubodial: diceColumnar: bricks standing on endSquamous: like floor tilesSimple Epithelium: single cell layerStratified Epithelium: multiple tiers of cellsPseudostratified Epithelium: a single layer ofcells varying in height2. Connective TissueConsists of a sparse population of cells scattered though an extracellular matrixMajor Types of Connective Tissue in Vertebrae…Loose Connective Tissue: collagenous, elastic, and reticular fibers bind to underlying tissues and hold organs in placeCartilage: abundance of collagenous fibers embedded in a rubbery matrix made of a protein-carb complex called chondroitin sulfateFibrous Connective Tissue: dense with collagenous fibers; form parallel bundles to maximize nonelastic strength; tendons (attach muscle to bone) and ligaments (connect bones at joints)Adipose Tissue: loose connective tissue that stores fat in adipose cells distributed throughout the matrix; insulates the body and stores fuel as fat molecules
5Animal Tissues Continued Connective Tissue (Cont.)Blood: liquid ECM (plasma); consists of water, salts, and dissolved proteins; erythrocytes (red blood cells), leukocytes (white blood cells), and cell fragments (platelets)Bone: mineralized connective tissue; bone-forming cells are called osteoblastsThe connective tissue that holds many tissues/organs together and in place contains scattered cells of varying function…Fibroblasts: cells that secrete the protein ingredients of the extracellular fibersMacrophages: cells that engulf foreign particles and debris of dead cells by phagocytosisCOMPREHENSION CHECK:Connective Tissue Review3. Muscle TissueFilaments containing the proteins actin and myosin, which enable muscles to contractSkeletal Muscle: known as striated muscle due to a striped (striated) appearance; responsible for voluntary movement; consists of long cells called muscle cellsCardiac Muscle: forms the contractile wall of the heart; striated and has contractile properties similar to skeletal muscle; unconscious task=contraction of the heartSmooth Muscle: responsible for involuntary body activities; lacks striations; found in the walls of the digestive tract, urinary bladder, arteries, and other internal organsMuscle Tissue Video4. Nervous TissueNeurons (nerve cells) have extensions (axons) that arespecialized to transmit nerve impulsesGlial cells (glia) help nourish, insulate, and replenish neurons
6Communication: Nervous System vs. Endocrine System Neurons transmit electric/chemical signals to specific target cellsNerve impulses travel along the neuron extensions (axons)Info conveyed by the specific pathways that the signal takesTransmission is very fast, each impulse takes fraction of a secondto reach target cellWell suited for rapid responses to environment and controllingfast locomotion and behavior.Ex: Impulses cause your hand to pull away quickly from a hot surface.Endocrine SystemHormones are signaling molecules that are released into thebloodstream to reach all locations in the body.Different hormones cause specific effects and only cells with thespecific receptors for the particular hormone responds.Depending on which cells have the specific receptor for the hormone, the hormone may have only one effect in one location or in many sites throughout the body.It is slow acting, but long term. This is because the hormone remains in the bloodstream and target tissue for a longer time period.Ex: Insulin controls levels of glucose in the blood by binding to and regulating virtually every cell outside the brain
7Regulators and Conformers A regulator for an environmental variable uses internal control mechanisms to regulate homeostasis when faced with an external change.A river otter keeps its body at a constant temperature regardless of the temperature of the water which it swims in.A conformer for an environmental variable conforms its internal conditions to conform to the extern changes in the environment.A largemouth bass conforms its internal temperature to the lake it lives in.An organism can be a conformer and a regulator to different environmental variables.The bass is a conformer for temperature, but is a regulator for solute concentration. The concentration in its blood and fluid differs from the concentration of the water it lives in.
8Homeostasis: Positive and Negative Feedback Homeostasis is state in when the organism maintains a constant internal environment despite external environmental changes.The organism maintains a specific variable at or near a set point.A stimulus fluctuates the variable from the set point, and the sensor detects the stimulus to trigger a physiological response that helps return the variable to the set point.Negative feedback reduces the stimulus to prevent the reaction from continuing.Exercise increases body temperature. The nervous system detects this increase and triggers sweating. The evaporation of moisture cools body to return temperature to the set point.The presence of a product of the system results in adecrease in the production of that product.Ex: trp operon.Positive feedback amplifies the stimulus where the productof a reaction influences or increases the forward directionof the system.In child birth, the pressure of the baby’s head stimulatesthe uterus to contract, which results in greater pressureand heightening the contractions.
9Thermoregulation-Thermoregulation is the process by which animals maintain their internal temperature within a tolerable range.-Ectotherms and endotherms manage their heat budgets very differently1. Endothermic animals, such as birds and mammals, use metabolic heat to regulate their body temperature.2. Ectothermic animals, such as snakes and most fishes, gain most of their heat from the external environment.EctothermEndotherm
10Vasodilation vs. Vasoconstriction -Many endotherms and ectotherms can alter the amount of blood flow between the body core and the skin.Vasodilation is an increase in the diameter of surface blood vessels near the body surface.Triggered by nerve signals that relax the musclesIn endotherms, vasodilation usually warms the skin, increasing the transfer of body heat.- LizardThe reverse process, vasoconstriction, reduces blood flow and heat transfer by decreasing the diameter of surface vessels.-Jack Rabbit, blood vessels in the ears keeps it from overheating
11Countercurrent Exchange Another circulatory adaptation is countercurrent exchange, the transfer of heat or solutes in adjacent fluids that flow in opposite directions.Countercurrent heat exchanger- an antiparallel arrangement of blood vessels that involves heat transferArteries and veins are near one another. As warm blood passes through the arteries, heat transfers to the colder venous blood returning from the extremities.
12Ectotherms and Endotherms Many animals can adjust to a new range of environmental temperatures by a physiological response called acclimatization.Ectotherms and endotherms acclimatize differently.In endotherms, acclimatization often includes adjusting the amount of insulation- growing fur and sheddingIn ectotherms, there are adjustments at the cellular levelCells may increase the production of certain enzymesMembranes change the proportions of saturated and unsaturated lipids to remain fluid at different temperatures.Some ectotherms produce “antifreeze” compounds, or cryoprotectants, to prevent ice formation in body cells.Bear is an example of an endotherm acclimation. Bear has a thicker coat in winter and sheds it in the summer.
13Bioenergetics and Metabolic Rates Bioenergetics: the overall flow and transformation of energy in an organismA Metabolic Rate is the sum of all the biochemical reactions that use energy over a given period of time.Energy is measured in Joules or CaloriesEnergy can be measured by Rates of Oxygen inhaled and CO2 produced.
14BMR vs. SMRBasal Metabolic Rate (BMR) is the minimum metabolic rate of an animal at rest and not experiencing stress. BMR is measured at a “comfortable” temperature.Standard Metabolic Rate (SMR) is the metabolic rate of an unstressed animal at rest at a particular temperature.
15Energy Budgets and Size The relationship between metabolic rate and size are directly related.
16Energy ConservationTorpor is a physiological state in which activity is low and metabolism decreases.Hibernation is a long-term torpor is reaction to winter coldness and food scarcity.Estivation is a summer torpor in response to high temperatures and food scarcity.Some animals exhibit a daily torpor usually as an adaptation to feeding patterns. Ex: Bats
17COMPREHENSION CHECK Torpor Estivation Hibernation Daily Torpor BMR SMR __ Long-term period of sleep during summer months __ General term for a change in activity and metabolism __ Metabolic rate at a particular temperature __ Metabolic rate at a comfortable temperature __ Bats feeding in the night and go dormant during the day __ A grizzly bear in the winter monthsTorporEstivationHibernationDaily TorporBMRSMRBAFEDC