© 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko
PowerPoint Lectures forCampbell Biology: Concepts & Connections, Seventh EditionReece, Taylor, Simon, and Dickey
Chapter 20 Unifying Concepts of Animal Structure and Function
▪ How can geckos climb walls and stick to the ceiling?– The surfaces of gecko toes are covered by millions of
microscopic hairs.– Each hair has a slight molecular attraction that helps it
stick to the surface.– This adhesive relationship is an example of the
correlation between structure and function.
Introduction
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Figure 20.0_1
Figure 20.0_2Chapter 20: Big Ideas
Structure and Functionin Animal Tissues
Organs and OrganSystems
External Exchange andInternal Regulation
Figure 20.0_3
STRUCTURE AND FUNCTION IN ANIMAL TISSUES
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20.1 Structure fits function at all levels of organization in the animal body
▪ Anatomy is the study of structure.▪ Physiology is the study of function.▪ Animals consist of a hierarchy of levels or
organization.– Tissues are an integrated group of similar cells that
perform a common function.– Organs perform a specific task and consist of two or
more tissues. – Organ systems consist of multiple organs that together
perform a vital body function.
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Figure 20.1
Tissue levelMuscle tissue
Cellular levelMuscle cell
Organ levelHeart
Organ system levelCirculatory system
Organism levelMany organ systemsfunctioning together
20.2 EVOLUTION CONNECTION: An animal’s form reflects natural selection
▪ The body plan or design of an organism– reflects the relationship between form and function,
– results from natural selection, and
– does not imply a process of conscious invention.
▪ Streamlined and tapered bodies– increase swimming speeds and
– have similarly evolved in fish, sharks, and aquatic birds and mammals, representing convergent evolution.
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Video: Shark Eating a SealVideo: Galápagos Sea Lion
Figure 20.2
Seal
Shark
Penguin
20.3 Tissues are groups of cells with a common structure and function
▪ Tissues
– are an integrated group of similar cells that perform a common function and
– combine to form organs.
▪ Animals have four main categories of tissues:1. epithelial tissue,
2. connective tissue,
3. muscle tissue, and
4. nervous tissue.
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20.4 Epithelial tissue covers the body and lines its organs and cavities
▪ Epithelial tissues, or epithelia, are sheets of closely packed cells that– cover body surfaces and
– line internal organs and cavities.
▪ Epithelial cells come in three shapes:1. squamous—like a fried egg,
2. cuboidal—as tall as they are wide, and
3. columnar—taller than they are wide.
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20.4 Epithelial tissue covers the body and lines its organs and cavities
▪ Epithelial tissues are named according to the– number of cell layers they have and
– shape of the cells on their apical surface.
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Figure 20.4
Stratified squamousepithelium
Pseudostratifiedciliated columnarepithelium
Simple columnarepithelium
Simple cuboidalepithelium
Simple squamousepithelium
Basallamina
Underlyingtissue
Apical surface ofepithelium
Cell nuclei
20.5 Connective tissue binds and supports other tissues
▪ Connective tissue can be grouped into six major types.1. Loose connective tissue
– is the most widespread,
– consists of ropelike collagen and elastic fibers that are strong and resilient, and
– helps to join skin to underlying tissues.
2. Fibrous connective tissue – has densely packed collagen fibers and
– forms tendons that attach muscle to bone.
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20.5 Connective tissue binds and supports other tissues
3. Adipose tissue stores fat in large, closely packed cells held in a matrix of fibers.
4. Cartilage– is a strong and flexible skeletal material and
– commonly surrounds the ends of bones.
5. Bone– has a matrix of collagen fibers
– embedded in a hard mineral substance containing calcium, magnesium, and phosphate.
6. Blood transports substances throughout the body.
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Figure 20.5
CellnucleusCollagenfiberElasticfibers
Loose connective tissue(under the skin)
Cell nucleus
Collagenfibers
Fibrous connectivetissue (forming a tendon)
Fat droplets
Adiposetissue
White bloodcells
Red bloodcell
PlasmaBlood
Centralcanal
Matrix
BoneBone-formingcells
Cartilage-formingcells
Matrix
Cartilage(at the endof a bone)
Figure 20.5_1
Cellnucleus
Collagenfiber
Elasticfibers
Loose connective tissue(under the skin)
Figure 20.5_2
Cell nucleus
Collagenfibers
Fibrous connectivetissue (forming a tendon)
Figure 20.5_3
Fat droplets
Adiposetissue
Figure 20.5_4
Cartilage-formingcells
Matrix
Cartilage(at the endof a bone)
Figure 20.5_5
Centralcanal
Matrix
Bone
Bone-formingcells
Figure 20.5_6
White bloodcells
Red bloodcell
PlasmaBlood
20.6 Muscle tissue functions in movement
▪ Muscle tissue is the most abundant tissue in most animals.
▪ There are three types of vertebrate muscle tissue:1. Skeletal muscle causes voluntary movements.
2. Cardiac muscle pumps blood.
3. Smooth muscle moves walls of internal organs, such as the intestines.
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Figure 20.6
Unit ofmusclecontraction
Musclefiber(cell)
Nuclei
Skeletalmuscle
Musclefiber
Nucleus
Junctionbetweentwo cells
Cardiac
muscle
Musclefiber
Smooth
muscle
Nucleus
Figure 20.6_1
Unit ofmusclecontraction
Musclefiber(cell)
Nuclei
Skeletalmuscle
Figure 20.6_2
Musclefiber
Nucleus
Junctionbetweentwo cells
Cardiac
muscle
Figure 20.6_3
Musclefiber
Smooth
muscle
Nucleus
20.7 Nervous tissue forms a communication network
▪ Nervous tissue– senses stimuli and– rapidly transmits information.
▪ Neurons carry signals by conducting electrical impulses.▪ Other cells in nervous tissue
– insulate axons,– nourish neurons, and– regulate the fluid around neurons.
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Figure 20.7
Dendrites
Cell body
Axon
ORGANS AND ORGAN SYSTEMS
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20.8 Organs are made up of tissues
▪ Each tissue performs specific functions.
▪ The heart has– extensive muscle that generates contractions,
– epithelial tissues that line the heart chambers,
– connective tissues that make the heart elastic, and
– neurons that regulate contractions.
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20.8 Organs are made up of tissues
▪ The small intestine– is lined by a columnar epithelium,
– includes connective tissues that contain blood vessels, and
– has two layers of smooth muscle that help propel food.
▪ The inner surface of the small intestine has many fingerlike projections that increase the surface area for absorption.
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Figure 20.8
Small intestine
LumenEpithelial tissue
(columnar epithelium)
Connective tissue
Smooth muscletissue (two layers)
Connective tissueEpithelial tissue
▪ Bioengineering is seeking ways to repair or replace damaged tissues and organs.
▪ New tissues and organs are being grown using a patient’s own cells.
▪ These techniques– remove the risk of tissue rejection and
– may someday reduce the shortage of organs available for transplants.
20.9 CONNECTION: Bioengineers are learning to produce tissues and organs for transplants
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Figure 20.9
20.10 Organ systems work together to perform life’s functions
▪ Each organ system– typically consists of many organs,
– has one or more functions, and
– works with other organ systems to create a functional organism.
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Figure 20.10_L
Bloodvessels
Heart
Circulatorysystem
Respiratorysystem
Nasalcavity
PharynxLarynxTracheaBronchusLung
Bone
Cartilage
Skeletal system
Muscular system
Skeletal muscles
Integumentary system
Hair
Skin
Nails
Urinarysystem
Digestivesystem
Urinarybladder
SmallintestineLargeintestine
Kidney
Ureter
Urethra
MouthEsophagusLiverStomach
Anus
Figure 20.10_REndocrine system
Thymus
Adrenalgland
Pancreas
Testis(male)
Hypothalamus
Pituitary gland
Thyroid gland
Parathyroidgland
Ovary(female)
Lymphatic andimmune systems
Lymphnodes
Appendix
Bonemarrow
Thymus
Spleen
Lymphaticvessels
Reproductivesystem
FemaleOviduct
Ovary
UterusVagina
Male
SeminalvesiclesProstateglandVasdeferens
PenisUrethraTestis
Nervous system Brain
Sense organ(ear)
Spinal cordNerves
▪ The skeletal and muscular systems support and move the body.
▪ The digestive and respiratory systems obtain food and oxygen.
▪ The circulatory system transports these materials.
▪ The urinary system disposes of wastes.
▪ The integumentary system covers the body.
20.10 Organ systems work together to perform life’s functions
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Figure 20.10_1
Circulatorysystem
Respiratory
systemNasalcavity
Bloodvessels
Heart
PharynxLarynxTracheaBronchusLung
Figure 20.10_2
Integumentary system
Hair
Skin
Nails
Figure 20.10_3
Bone
Cartilage
Skeletal system
Figure 20.10_4
Muscular system
Skeletal muscles
Figure 20.10_5
Urinary
system
Digestivesystem
Urinarybladder
Smallintestine
Largeintestine
Kidney
Ureter
Urethra
MouthEsophagus
LiverStomach
Anus
▪ The lymphatic and immune systems protect the body from infection.
▪ The nervous and endocrine systems control and coordinate body functions.
▪ The reproductive system produces offspring.
20.10 Organ systems work together to perform life’s functions
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Figure 20.10_6
Endocrine system
Thymus
Adrenalgland
Pancreas
Testis(male)
Hypothalamus
Pituitary gland
Thyroid gland
Parathyroidgland
Ovary(female)
Figure 20.10_7
Lymphatic andimmune systems
Lymphnodes
Appendix
Bonemarrow
Thymus
Spleen
Lymphaticvessels
Figure 20.10_8
Nervous system Brain
Sense organ(ear)
Spinal cord
Nerves
Figure 20.10_9
Reproductivesystem
FemaleOviduct
Ovary
UterusVagina
Male
SeminalvesiclesProstateglandVasdeferensPenisUrethraTestis
20.11 CONNECTION: New imaging technology reveals the inner body
▪ New technologies– are used in medical diagnosis and research and– allow physicians to examine organ systems without
surgery.
▪ X-rays help create images of hard structures such as bones and teeth.▪ Magnetic resonance imaging (MRI)
– takes advantage of the behavior of the hydrogen atoms in water molecules and
– provides three-dimensional images of very small structures.
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Figure 20.11A
Femur(thigh bone)
Torn meniscus
Tibia (shin bone)
▪ A newer X-ray technology called computed tomography (CT)– produces high-resolution images of cross sections of the
body and
– can detect small differences between normal and abnormal tissues in many organs.
▪ Positron-emission tomography (PET) helps identify metabolic processes at specific body locations.
▪ CT and PET images can be combined for an even more informative image.
20.11 CONNECTION: New imaging technology reveals the inner body
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Figure 20.11B
20.12 The integumentary system protects the body
▪ The skin consists of two layers:1. The epidermis
– is a stratified squamous epithelium and
– forms the surface of the skin.
2. The dermis– forms a deeper skin layer and
– is composed of dense connective tissue with many resilient elastic fibers and strong collagen fibers.
– The dermis contains hair follicles, oil and sweat glands, muscle cells, nerves, sensory receptors, and blood vessels.
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Figure 20.12
Epidermis
Dermis
Hypodermis(under the skin)
Adipose tissue
Blood vessels
Hair follicle
Oil gland
Sweatgland
Nerve
Muscle
Sweatpore
Hair
▪ Skin has many functions.– The epidermis
– resists physical damage,
– decreases water loss, and
– prevents penetration by microbes.
– The dermis– collects sensory information,
– synthesizes vitamin D, and
– helps regulate body temperature.
20.12 The integumentary system protects the body
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▪ Exposure of the skin to ultraviolet light– causes skin cells to release melanin, which contributes
to a visible tan, and
– damages DNA of skin cells and can lead to– premature aging of the skin,
– cataracts, and
– skin cancers.
20.12 The integumentary system protects the body
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▪ Hair– is an important component of the integumentary system
of mammals,– helps to insulate their bodies, and– consists of a shaft of keratin-filled dead cells.
▪ Oil glands release oils that– are associated with hair follicles,– lubricate hair,– condition surrounding skin, and– inhibit the growth of bacteria.
20.12 The integumentary system protects the body
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EXTERNAL EXCHANGE AND INTERNAL REGULATION
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20.13 Structural adaptations enhance exchange with the environment
▪ Every organism is an open system that must exchange matter and energy with its surroundings.
▪ Cells in small and flat animals can exchange materials directly with the environment.
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20.13 Structural adaptations enhance exchange with the environment
▪ However, as organisms increase in size, the surface area
– is too small for the corresponding volume and
– too far away from the deepest cells of the body.
– In these organisms, evolutionary adaptations
– consist of extensively branched or folded surfaces, which increase the area of these surfaces and
– provide for sufficient environmental exchange.
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20.13 Structural adaptations enhance exchange with the environment
▪ The respiratory system exchanges gases between the external environment and blood.▪ The digestive system acquires food and eliminates
wastes.▪ The excretory system eliminates metabolic waste.▪ The circulatory system
– distributes gases, nutrients, and wastes throughout the body and
– exchanges materials between blood and body cells through the interstitial fluid that bathes body cells.
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Figure 20.13AEXTERNAL ENVIRONMENTMouth Food CO2 O2
ANIMAL
Digestivesystem
Respiratorysystem
Circulatorysystem
Urinarysystem
HeartInterstitialfluid
Bodycells
Intestine
Anus
Unabsorbedmatter (feces)
Metabolic wasteproducts (urine)
Nutrients
Bloo
d
Figure 20.13B
Trachea
▪ Homeostasis is the active maintenance of a steady state within the body.– External environmental conditions may fluctuate wildly.
– Homeostatic mechanisms regulate internal conditions.
20.14 Animals regulate their internal environment
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Figure 20.14_UN
Figure 20.14
Homeostaticmechanisms
Externalenvironment
Largefluctuations
Internalenvironment
Smallfluctuations
▪ Control systems– detect change and– direct responses.
▪ Negative-feedback mechanisms– keep internal variables steady and– permit only small fluctuations around set points.
20.15 Homeostasis depends on negative feedback
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Animation: Negative Feedback
Animation: Positive Feedback
Figure 20.15_s1
Homeostasis:Body temperature
approximately 37°C
Figure 20.15_s2
Brain activatescoolingmechanisms.
Brainactivateswarming mechanisms.
Temperature risesabove set point
Temperature fallsbelow set point
Homeostasis:Body temperature
approximately 37°C
Figure 20.15_s3Sweat evaporates,cooling the body.
Blood vessels dilate.
Brain activatescoolingmechanisms.
Blood vessels constrict.
Brainactivateswarming mechanisms.Shivering generates
heat.
Temperature risesabove set point
Temperature fallsbelow set point
Homeostasis:Body temperature
approximately 37°C
Figure 20.15_s4Sweat evaporates,cooling the body.
Blood vessels dilate.
Brain activatescoolingmechanisms.
Cooling mechanismsshut off.
Warming mechanismsshut off.
Blood vessels constrict.
Brainactivateswarming mechanisms.Shivering generates
heat.
Temperaturedecreases
Temperatureincreases
Temperature risesabove set point
Temperature fallsbelow set point
Homeostasis:Body temperature
approximately 37°C
Figure 20.15_5
Homeostasis:Body temperature
approximately 37°C
Temperaturedecreases
Temperature risesabove set point
The thermostat shuts offthe cooling mechanisms.
Blood vessels in the skin dilate,
increasing heat loss.
Sweat glands secrete sweat thatevaporates, cooling the body. The thermostat
in the brainactivates cooling mechanisms.
Figure 20.15_6
Homeostasis:Body temperature
approximately 37°C
Temperatureincreases
Temperature fallsbelow set point
The thermostat shuts offthe warming mechanisms.
Blood vessels in the skin constrict,
minimizing heat loss.
Skeletal muscles contract;shivering generates heat.
The thermostatin the brainactivates warmingmechanisms.
You should now be able to
1. Describe the levels of organization in an animal’s body.
2. Explain how size and shape can influence the structure of an animal.
3. Define a tissue, describe the four main types of animal tissue, and note their structures and their functions.
4. Explain how the structure of organs is based on the cooperative interactions of tissues.
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5. Explain how artificial tissues are created and used.
6. Describe the general structures and functions of the 12 major vertebrate organ systems.
7. Describe and compare X-ray, CT, MRI, and PET imaging technologies.
8. Relate the structure of the skin to its functions.
You should now be able to
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9. Describe the systems that help an animal exchange materials with its environment.
10. Describe examples of adaptations to increase the surface-to-volume ratio.
11. Define the concept of homeostasis and illustrate it with examples.
12. Explain how negative feedback is used to regulate internal body temperature.
You should now be able to
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Figure 20.UN01
20.4 Epithelial tissuecovers the body andlines its organs andcavities.
20.5 Connectivetissue binds andsupports othertissues.
20.6 Muscletissue functionsin movement.
20.7 Nervous tissueforms acommunicationnetwork.
Sheets of closelypacked cells
Sparse cells in extra-cellular matrix
Long cells (fibers)with contractileproteins
Neurons withbranching extensions;supporting cells
Columnar epithelium Loose connective tissue Skeletal muscle Neuron
Exam
ple
Stru
ctur
eFu
nctio
n
Figure 20.UN01_1
20.4 Epithelial tissuecovers the body andlines its organs andcavities.
20.5 Connectivetissue binds andsupports othertissues.
Sheets of closelypacked cells
Sparse cells in extra-cellular matrix
Columnar epithelium Loose connective tissue
Exam
ple
Stru
ctur
eFu
nctio
n
Figure 20.UN01_2
Exam
ple
Stru
ctur
eFu
nctio
n 20.6 Muscletissue functionsin movement.
20.7 Nervous tissueforms acommunicationnetwork.
Long cells (fibers)with contractileproteins
Neurons withbranching extensions;supporting cells
Skeletal muscle Neuron
Figure 20.UN02
a.
b.
c.
d.e.