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