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AN INTRODUCTION TO ANIMAL STRUCTURE AND
FUNCTION
CHAPTER 40CHAPTER 40
LEVELS OF ORGANIZATION
Hierarchy = cell, tissue, organs, Hierarchy = cell, tissue, organs, organ systemsorgan systems
TissueTissue = group of cells with = group of cells with common structure and functioncommon structure and function
Cells held together by sticky Cells held together by sticky coating or woven in fiberscoating or woven in fibers
Figure 40.1 The structure and function of epithelial tissues
CATEGORIES OF TISSUES Epithelial TissueEpithelial Tissue
Tightly packed cells with tight Tightly packed cells with tight junctionsjunctions
Covers outside of body and Covers outside of body and lines organs and body cavitieslines organs and body cavities
Free surface exposed to air or Free surface exposed to air or fluid and cells at base of fluid and cells at base of barrier attached to basement barrier attached to basement membranemembrane
Types (may occur in Types (may occur in combination)combination)SimpleSimple – one layer of cells – one layer of cellsStratifiedStratified – multiple layers – multiple layersCuboidalCuboidal – dice – diceColumnarColumnar – bricks – bricksSquamousSquamous – flat tiles – flat tiles
Figure 40.1x Epithelial tissues
Connective tissueConnective tissueFew cells scattered throughout Few cells scattered throughout
extracellular matrixextracellular matrixBinds and supports tissuesBinds and supports tissuesLoose weave of three types Loose weave of three types
proteinaceous fibersproteinaceous fibersCollagenousCollagenous – collagen; strong – collagen; strong and resist stretchingand resist stretching
ElasticElastic – elastin; return to – elastin; return to original shapeoriginal shape
ReticularReticular – branched, join to – branched, join to adjacent tissuesadjacent tissues
Types of Connective TissueTypes of Connective TissueLooseLoose
• Fibroblasts secrete Fibroblasts secrete proteins (for fibers)proteins (for fibers)
• Macrophages immune Macrophages immune defensedefense
AdiposeAdipose• Insulates and stores fuelInsulates and stores fuel• Fat dropletFat droplet
FibrousFibrous
• Bundles of collagenous fibersBundles of collagenous fibers
• Found in tendons and Found in tendons and ligamentsligaments
CartilageCartilage
• Collagenous fibers Collagenous fibers embedded in chondroitin embedded in chondroitin sulfate secreted by sulfate secreted by chondrocyteschondrocytes
BoneBone• MineralizedMineralized• Osteoblasts deposit Osteoblasts deposit collagen and calcium collagen and calcium phosphate which hardens phosphate which hardens into hydroxyapatiteinto hydroxyapatite
BloodBlood• Plasma, water, salts, Plasma, water, salts, proteinprotein
• Blood CellsBlood Cells
–ErythrocytesErythrocytes (red) – carry (red) – carry OO22 and CO and CO22
–LeukocytesLeukocytes (white) – fight (white) – fight diseasedisease
–PlateletsPlatelets (fragments) – clot (fragments) – clot
Figure 40.2 Some representative types of connective tissue
Figure 40.2x Connective tissue
Nervous TissueNervous Tissue – transmit – transmit signalssignalsNeuronNeuron – nerve cell – nerve cell
DendritesDendrites – extensions – extensions conduct to cell bodyconduct to cell body
AxonsAxons – extensions – extensions conduct away from cell bodyconduct away from cell body
Figure 40.3 The basic structure of a neuron
Muscle TissueMuscle TissueCells contractCells contract
ActinActin and and myosinmyosin are are contractile proteinscontractile proteins
Types of muscleTypes of muscleSkeletalSkeletal
• Voluntary movementsVoluntary movements• striatedstriated
CardiacCardiac
• Contractile wall of heartContractile wall of heart
• Striated and branchedStriated and branchedSmoothSmooth
• Walls of internal organsWalls of internal organs
• Involuntary movementsInvoluntary movements
• Not striatedNot striated
Figure 40.4 Three kinds of vertebrate muscle
Figure 40.4x Three kinds of vertebrate muscle
Figure 40.5x Stomach: Stomach wall showing the three tunics (left), gastric glands and pits (right)
Controlling internal environment RegulatorRegulator – an animal that uses – an animal that uses
internal control mechanisms to regulate internal control mechanisms to regulate something in response to environmentsomething in response to environment Homeostasis Homeostasis – maintaining a steady – maintaining a steady
statestate ConformerConformer – an animal that allows the – an animal that allows the
internal condition to conform to the internal condition to conform to the external changesexternal changes
BIOENERGETICS
Metabolic rateMetabolic rate – total amount – total amount of energy an animal loses per of energy an animal loses per unit time; usually measured in unit time; usually measured in calories or kilocaloriescalories or kilocaloriesMeasured by amount of Measured by amount of
oxygen used or amount of oxygen used or amount of heat lossheat loss
Minimum rates support basic Minimum rates support basic functions of lifefunctions of life
Maximum rates occur during peak Maximum rates occur during peak activityactivity
EndothermsEndotherms – generate their own – generate their own body heat metabolicallybody heat metabolicallyExamples: birds and mammalsExamples: birds and mammalsBasal metabolic rate (BMRBasal metabolic rate (BMR)) – –
under resting, fasting, non-under resting, fasting, non-stressful conditionsstressful conditions
Average female BMR = Average female BMR = 1300 - 1500 kcal/day1300 - 1500 kcal/day
Average male BMR = Average male BMR = 1600 – 1800 kcal/day1600 – 1800 kcal/day
EctothermsEctotherms – acquire most of – acquire most of their body heat from their body heat from environmentenvironmentExamples: most fish, Examples: most fish,
amphibians, reptiles, and amphibians, reptiles, and invertebratesinvertebrates
Figure 40.12 Maximum metabolic rates over different time spans
Standard metabolic rate Standard metabolic rate (SMR)(SMR) – under – under controlled controlled temptemp, resting, fasting, and , resting, fasting, and non-stressful conditionsnon-stressful conditions
Metabolic rate per gram is Metabolic rate per gram is inversely related to body size inversely related to body size among similar animalsamong similar animalsSmaller animals consume Smaller animals consume
more calories per gram than more calories per gram than larger animalslarger animals
Figure 40.13a Annual energy budgets for four animals: Total annual energy expenditures
Figure 40.13b Annual energy budgets for four animals: Energy expenditure per unit mass
BODY PLANS AND ENVIRONMENT Physical support on land Physical support on land
depends on adaptations of body depends on adaptations of body proportions and postureproportions and posture
In mammals and birds, leg In mammals and birds, leg position more important than position more important than leg bone sizeleg bone size
Animal cells must have enough Animal cells must have enough surface area in contact with surface area in contact with aqueous mediumaqueous mediumUpper limits of cell size imposed Upper limits of cell size imposed
by surface to volume ratioby surface to volume ratioAs cell size increases, volume As cell size increases, volume increases proportionally more increases proportionally more than surface areathan surface area
Maximize surface areaMaximize surface area
Figure 40.8 Internal exchange surfaces of complex animals
REGULATING INTERNAL ENVIRONMENT HomeostasisHomeostasis – dynamic – dynamic
equilibriumequilibriumReceptorReceptor – detects internal – detects internal
changechangeControl centerControl center- processes - processes
info from receptor and directs info from receptor and directs effector to respondeffector to respond
EffectorEffector – provides the – provides the responseresponse
Figure 40.10 Bioenergetics of an animal: an overview
Negative feedbackNegative feedback – stops or – stops or reduces intensity of original stimulus reduces intensity of original stimulus and thus the new change is opposite and thus the new change is opposite in direction the initial changein direction the initial changeMost common homeostatic Most common homeostatic
mechanism in animalsmechanism in animalsThermostat controlThermostat controlHypothalamus detects high blood Hypothalamus detects high blood
temp, so increases sweating to temp, so increases sweating to induce evaporative coolinginduce evaporative cooling
Figure 40.9a An example of negative feedback: Control of room temperature
Figure 40.9b An example of negative feedback: Control of body temperature
Positive feedbackPositive feedback – enhances – enhances the initial change in a variablethe initial change in a variableMore rareMore rareDuring childbirth, pressure During childbirth, pressure
against uterine opening against uterine opening stimulates contractions which stimulates contractions which causes greater pressure causes greater pressure against uterine openingagainst uterine opening