Animal Structure and Animal Structure and Function: An IntroductionFunction: An Introduction

Chapter 38Chapter 38

KEY CONCEPTSKEY CONCEPTS

• Structure and function are closely linked at Structure and function are closely linked at every level of organizationevery level of organization

Learning Objective 1Learning Objective 1

• Compare the structure and function of the Compare the structure and function of the four main kinds of animal tissues: four main kinds of animal tissues: epithelialepithelial, , connectiveconnective, , musclemuscle, and , and nervousnervous

TissueTissue

• A group of similarly specialized cellsA group of similarly specialized cells

• Associated to perform one or more Associated to perform one or more functionsfunctions

Epithelial TissueEpithelial Tissue (Epithelium)(Epithelium)

• A continuous layer (sheet) of cellsA continuous layer (sheet) of cells• covering a body surface covering a body surface • lining a body cavity lining a body cavity

• Functions in protection, absorption, Functions in protection, absorption, secretion, or sensationsecretion, or sensation

Connective Tissue 1Connective Tissue 1

• Relatively few cells separated by Relatively few cells separated by intercellular substanceintercellular substance

• fibersfibers scattered throughout a scattered throughout a matrixmatrix

• Intercellular substance fibersIntercellular substance fibers• collagen fiberscollagen fibers• elastic fiberselastic fibers• reticular fibersreticular fibers

Connective Tissue 2Connective Tissue 2

• Contains specialized cellsContains specialized cells• such as such as fibroblastsfibroblasts and and macrophagesmacrophages

• Functions:Functions:• joins other body tissues joins other body tissues • supports body and organssupports body and organs• protects underlying organsprotects underlying organs

Muscle TissueMuscle Tissue

• Consists of cells specialized to contractConsists of cells specialized to contract

• Each cell is an elongated muscle fiberEach cell is an elongated muscle fiber• many contractile units (many contractile units (myofibrils)myofibrils)

Nervous TissueNervous Tissue

• NeuronsNeurons• elongated cellselongated cells• specialized for transmitting impulsesspecialized for transmitting impulses

• Glial cellsGlial cells • support and nourish neuronssupport and nourish neurons

Learning Objective 2Learning Objective 2

• Compare the structure and function of the Compare the structure and function of the main types of main types of epithelial tissueepithelial tissue

Epithelial TissueEpithelial Tissue

• Epithelial cell shapesEpithelial cell shapes• squamoussquamous, , cuboidalcuboidal, , columnarcolumnar

• Epithelial tissue structureEpithelial tissue structure• simplesimple, , stratifiedstratified, , pseudostratifiedpseudostratified • (See Table 38-1)(See Table 38-1)

Simple Squamous EpitheliumSimple Squamous Epithelium

• Lines blood vessels and air sacs in lungsLines blood vessels and air sacs in lungs• Permits exchange of materials by diffusionPermits exchange of materials by diffusion

Simple Cuboidal and Simple Cuboidal and Columnar EpitheliaColumnar Epithelia

• Line passagewaysLine passageways• Specialized for secretion and absorption Specialized for secretion and absorption

Stratified Squamous EpitheliumStratified Squamous Epithelium

• Forms outer layer of skinForms outer layer of skin• Lines passageways into the bodyLines passageways into the body• Provides protection Provides protection

Pseudostratified EpitheliumPseudostratified Epithelium

• Lines passagewaysLines passageways• Protects underlying tissuesProtects underlying tissues

Glands 1Glands 1

• Specialized epithelial tissue Specialized epithelial tissue

• Goblet cellsGoblet cells • unicellular unicellular exocrine glandsexocrine glands that secrete that secrete

mucusmucus

Glands 2Glands 2

• Exocrine glandsExocrine glands • secrete product through a duct onto exposed secrete product through a duct onto exposed

epithelial surface epithelial surface

• Endocrine glandsEndocrine glands • release hormones into release hormones into interstitial fluidinterstitial fluid or blood or blood

GlandsGlands

Fig. 38-1, p. 809

Unicellular glands (goblet cells)Cilia

Basement membrane

Skin

(b) Sweat gland. (c) Parotid salivary gland.

(a) Goblet cells.

MembranesMembranes

• Epithelial membraneEpithelial membrane• sheet of epithelial tissuesheet of epithelial tissue• layer of underlying connective tissue layer of underlying connective tissue

• Mucous membraneMucous membrane • lines cavity that opens to outside of bodylines cavity that opens to outside of body

• Serous membraneSerous membrane • lines cavity that does not open to the outsidelines cavity that does not open to the outside

Learning Objective 3Learning Objective 3

• Compare the main types of Compare the main types of connective connective tissuetissue

• Summarize their functionsSummarize their functions

Connective TissuesConnective Tissues

• Cells embedded in Cells embedded in intercellular substanceintercellular substance • microscopic microscopic collagencollagen fibers, elastic fibersfibers, elastic fibers, ,

reticular fibersreticular fibers (thin branched fibers) (thin branched fibers) • scattered through a scattered through a matrixmatrix (thin gel of (thin gel of

polysaccharides)polysaccharides)

Loose Connective TissueLoose Connective Tissue

• CoConsists of nsists of fibersfibers running in various running in various directions through a semifluid directions through a semifluid matrixmatrix

• Flexible tissue forms a covering for Flexible tissue forms a covering for nerves, blood vessels, and musclesnerves, blood vessels, and muscles

Dense Connective TissueDense Connective Tissue

• Stronger, less flexible than loose Stronger, less flexible than loose connective tissue connective tissue

• Collagen Collagen fibersfibers arranged in definite pattern arranged in definite pattern

• Forms Forms • tendons tendons ((connect muscles to bones) connect muscles to bones) • ligamentsligaments (connect bones to bones) (connect bones to bones)

Dense Connective TissueDense Connective Tissue

Elastic Connective TissueElastic Connective Tissue

• Consists of bundles of parallel Consists of bundles of parallel elastic fiberselastic fibers

• Found in lung tissue, walls of large arteriesFound in lung tissue, walls of large arteries

Reticular Connective TissueReticular Connective Tissue

• Consists of interlacing Consists of interlacing reticular fibersreticular fibers

• Forms support framework for many organsForms support framework for many organs

Adipose TissueAdipose Tissue

• Consists of fat cellsConsists of fat cells

• Found with loose connective tissue in Found with loose connective tissue in subcutaneous tissuesubcutaneous tissue

Cartilage and BoneCartilage and Bone

• Form skeletons of vertebratesForm skeletons of vertebrates

• CartilageCartilage consists of consists of chondrocyteschondrocytes • in in lacunaelacunae (small cavities in hard matrix) (small cavities in hard matrix)• nonvascular nonvascular

• OsteocytesOsteocytes • secrete and maintain secrete and maintain bone matrixbone matrix • vascular vascular

Cartilage and BoneCartilage and Bone

• CartilageCartilage

• BoneBone

BoneBone

Fig. 38-2ab, p. 814

(a) The human skeleton consists mainly of bone.

(b) A bone is cut open, exposing its internal structure.

BloodBlood andand LymphLymph

• Circulating tissues Circulating tissues • fluid intercellular substances fluid intercellular substances

• Help parts of an animal communicate with Help parts of an animal communicate with one another one another

Learning Objective 4Learning Objective 4

• Contrast the three types of Contrast the three types of muscle tissuemuscle tissue and their functionsand their functions

Skeletal MuscleSkeletal Muscle

• StriatedStriated and under and under voluntary controlvoluntary control

• Elongated, cylindrical Elongated, cylindrical fibersfibers with with several several nucleinuclei

• Skeletal muscles contract, move parts of Skeletal muscles contract, move parts of the bodythe body

Cardiac MuscleCardiac Muscle

• StriatedStriated, contractions are , contractions are involuntaryinvoluntary

• Elongated, cylindrical Elongated, cylindrical fibersfibers branch and branch and fuse; fuse; one or two central nucleione or two central nuclei

• Muscle contracts, heart pumps bloodMuscle contracts, heart pumps blood

Smooth MuscleSmooth Muscle

• No striationsNo striations, contractions , contractions involuntaryinvoluntary

• Elongated, spindle-shaped Elongated, spindle-shaped fibersfibers with a with a single central nucleussingle central nucleus

• Smooth muscle moves body organs Smooth muscle moves body organs ((exampleexample: pushes food through digestive tract): pushes food through digestive tract)

Muscle TissuesMuscle Tissues

Learning Objective 5Learning Objective 5

• How does the structure of the How does the structure of the neuronneuron relate to its function?relate to its function?

NeuronNeuron

• Elongated cell Elongated cell

• Receives and transmits information Receives and transmits information

• SynapseSynapse • a junction between neuronsa junction between neurons

NeuronNeuron

• DendritesDendrites • receive signals receive signals • transmit signals to transmit signals to cell bodycell body

• AxonAxon • transmits signals away from cell body transmits signals away from cell body • to other neurons, muscles, glands to other neurons, muscles, glands

NeuronNeuron

Fig. 38-3, p. 817

Neurons

Dendrite

Nuclei of glial cells

Axon

100 µm

KEY CONCEPTSKEY CONCEPTS

• The main types of tissues in a complex The main types of tissues in a complex animal are epithelial, connective, muscle, animal are epithelial, connective, muscle, and nervousand nervous

Learning Objective 6Learning Objective 6

• Describe the Describe the organ systemsorgan systems of a mammal of a mammal

• Summarize the Summarize the homeostatichomeostatic actions of actions of each organ systemeach organ system

Organ SystemsOrgan Systems

• TissuesTissues and and organsorgans working together working together

• In mammals, 11 In mammals, 11 organ systemsorgan systems work work together in the together in the organismorganism

• Each Each organ systemorgan system functions to maintain functions to maintain homeostasishomeostasis

11 Organ Systems11 Organ Systems

IntegumentaryIntegumentary RespiratoryRespiratory

SkeletalSkeletal UrinaryUrinary

MuscularMuscular NervousNervous

Digestive Digestive EndocrineEndocrine

CardiovascularCardiovascular ReproductiveReproductive

Immune (lymphatic) Immune (lymphatic)

1111 Organ Organ SystemsSystems

1111 Organ Organ SystemsSystems

Insert “Human organ Insert “Human organ systems”systems”

organ_systems_v2.swforgan_systems_v2.swf

Watch body systems work Watch body systems work together by clicking on the figure together by clicking on the figure

in ThomsonNOW.in ThomsonNOW.

KEY CONCEPTSKEY CONCEPTS

• Tissues and organs form the 11 main Tissues and organs form the 11 main organ systems of a complex animalorgan systems of a complex animal

Learning Objective 7Learning Objective 7

• Define Define homeostasishomeostasis

• Contrast Contrast negativenegative and and positive feedback positive feedback systemssystems

HomeostasisHomeostasis

• Balanced internal environment (steady Balanced internal environment (steady state) state)

• Homeostatic mechanismsHomeostatic mechanisms• control processes that maintain conditionscontrol processes that maintain conditions

Negative Feedback Systems 1Negative Feedback Systems 1

• Maintain dynamic equilibrium (Maintain dynamic equilibrium (homeostasishomeostasis))

1. Stressor1. Stressor• causes change in some steady statecauses change in some steady state

2. Triggers a response2. Triggers a response• that opposes the change that opposes the change

Negative Feedback Systems 2Negative Feedback Systems 2

3. 3. SensorSensor detects change detects change• a deviation from desired condition (a deviation from desired condition (set point)set point)

4. Sensor signals an 4. Sensor signals an integratorintegrator (control center) (control center)

5. Integrator activates 5. Integrator activates effectorseffectors• organs or processes that restore steady stateorgans or processes that restore steady state

Negative FeedbackNegative Feedback

Fig. 38-5, p. 821

HOMEOSTASIS Stressor

5 Normal condition (set point) restored.

1 Stressor causes deviation from set point.

4 Integrator activates effectors (homeostatic mechanisms).

2 Sensor detects change from set point.

3 Sensor signals integrator (control center).

Positive Feedback SystemPositive Feedback System

• Deviation from steady state causes Deviation from steady state causes changes that intensify (rather than changes that intensify (rather than reverse) the changesreverse) the changes

Positive FeedbackPositive Feedback

Fig. 38-7, p. 822

Stressor: hemorrhage

Homeostasis

1 Loss of blood causes blood pressure to decrease.

4 Cardiac output decreases (heart pumps less blood).

2 Less blood circulates to heart.

3 Heart function declines.

KEY CONCEPTSKEY CONCEPTS

• Homeostatic mechanisms are responsible Homeostatic mechanisms are responsible for the body’s automatic tendency to for the body’s automatic tendency to maintain a relatively stable internal maintain a relatively stable internal environmentenvironment

Learning Objective 8Learning Objective 8

• Compare the costs and benefits of Compare the costs and benefits of ectothermyectothermy

ThermoregulationThermoregulation

• Process of maintaining body temperature Process of maintaining body temperature within certain limitswithin certain limits

• despite changes in surrounding temperature despite changes in surrounding temperature

• Animals have different structural, Animals have different structural, behavioral, and physiological strategies behavioral, and physiological strategies

EctothermsEctotherms

• In In ectothermsectotherms, body temperature depends , body temperature depends on temperature of environment on temperature of environment

• Use behavioral strategies to adjust body Use behavioral strategies to adjust body temperaturestemperatures

Costs and BenefitsCosts and Benefits

• Benefits of Benefits of ectothermyectothermy • very little energy used to maintain the very little energy used to maintain the

metabolic ratemetabolic rate• ectotherms can survive on less food ectotherms can survive on less food

• Disadvantage of Disadvantage of ectothermyectothermy • activity limited by daily and seasonal activity limited by daily and seasonal

temperature conditionstemperature conditions

Learning Objective 9Learning Objective 9

• Compare the costs and benefits of Compare the costs and benefits of endothermyendothermy

• Describe strategies animals use to adjust Describe strategies animals use to adjust to challenging temperature changesto challenging temperature changes

EndothermsEndotherms

• Have Have homeostatic homeostatic mechanismsmechanisms

• regulate body regulate body temperature within a temperature within a narrow rangenarrow range

Costs and BenefitsCosts and Benefits

• Benefits of Benefits of endothermyendothermy• high metabolic ratehigh metabolic rate• constant body temperature allows higher rate constant body temperature allows higher rate

of enzyme activityof enzyme activity• active even in low winter temperatures active even in low winter temperatures

• Disadvantage of Disadvantage of endothermyendothermy• high energy costhigh energy cost

Temperature Temperature Regulation in Regulation in

HumansHumans

Fig. 38-9, p. 823

Decreased muscle activity

NervesIncreased sweating/ panting

Evaporation

Smooth muscle in blood vessels relaxes

Blood vessels dilate

Sensors signal temperature- regulating center in hypothalamus (integrator)

Specialized nerve cells (sensors) detect change from set point

Body temperature increases

Body temperature decreases (normal condition restored)

Stressors HOMEOSTASIS Stressors

Fig. 38-9, p. 823

Body temperature increases (normal condition restored)

Body temperature decreases

Specialized nerve cells (sensors) detect change from set point

Sensors signal temperature- regulating center in hypothalamus (integrator)

Blood vessels constrict

Smooth muscle in blood vessels contracts

Nerves

Increase in voluntary movement; shivering

Increase in metabolic rate

Thyroid glandAnterior pituitary gland

Insert “Control of human Insert “Control of human body temperature”body temperature”

hot_guy_m.swfhot_guy_m.swf

AcclimatizationAcclimatization

• Process of adjustment to seasonal changesProcess of adjustment to seasonal changes

TorporTorpor• TorporTorpor

• adaptive hypothermia (in small endotherms adaptive hypothermia (in small endotherms when surrounding temperature drops) when surrounding temperature drops)

• HibernationHibernation • long-term torpor in response to winter coldlong-term torpor in response to winter cold

• EstivationEstivation • torpor due to lack of food or water during torpor due to lack of food or water during

summer heatsummer heat

KEY CONCEPTSKEY CONCEPTS

• Thermoregulation contributes to Thermoregulation contributes to homeostasishomeostasis

Insert “Human Insert “Human thermoregulation”thermoregulation”

temp_regulation.swftemp_regulation.swf

Explore negative feedback and Explore negative feedback and temperature regulation in temperature regulation in

humans and other animals by humans and other animals by clicking on the figures in clicking on the figures in

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