_20_Lecture_Presentation.ppt

PowerPoint Lectures forCampbell Biology: Concepts & Connections, Seventh EditionReece, Taylor, Simon, and Dickey

Chapter 20Chapter 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

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

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.

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.

Video: Shark Eating a SealVideo: Galápagos Sea Lion

Figure 20.2

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.

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.

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.

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.

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.

Figure 20.5

Cellnucleus

Collagenfiber

Elasticfibers

Loose connective tissue(under the skin)

Cell nucleus

Collagenfibers

Fibrous connectivetissue (forming a tendon)

Fat droplets

Adiposetissue

White bloodcells

Red bloodcell

PlasmaBlood

Centralcanal

Matrix

Bone-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-formingcells

Figure 20.5_6

White bloodcells

Red bloodcell

Plasma

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.

Figure 20.6

Unit ofmusclecontraction

Musclefiber(cell)

Nuclei

Skeletalmuscle

Musclefiber

Nucleus

Junctionbetweentwo cells

Cardiacmuscle

Musclefiber

Smoothmuscle

Nucleus

Figure 20.6_1

Unit ofmusclecontraction

Musclefiber(cell)

Nuclei

Skeletalmuscle

Figure 20.6_2

Musclefiber

Nucleus

Junctionbetweentwo cells

Cardiacmuscle

Figure 20.6_3

Musclefiber

Smoothmuscle

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.

Figure 20.7

Dendrites

Cell body

ORGANS AND ORGAN SYSTEMS

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.

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.

Figure 20.8

Small intestine

Epithelial tissue(columnar epithelium)

Connective tissue

Smooth muscletissue (two layers)

Connective tissue

Epithelial 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

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.

Figure 20.10_L

Bloodvessels

Circulatorysystem

Respiratorysystem

Nasalcavity

Pharynx

Larynx

Trachea

Bronchus

Cartilage

Skeletal system

Muscular system

Skeletal muscles

Integumentary system

Urinarysystem

Digestivesystem

Urinarybladder

Smallintestine

Largeintestine

Kidney

Ureter

Urethra

Esophagus

Stomach

Figure 20.10_R

Endocrine 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

UterusVagina

Seminalvesicles

Prostategland

Vasdeferens

UrethraTestis

Nervous system Brain

Sense organ(ear)

Spinal cord

Nerves

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.

Figure 20.10_1

Circulatorysystem

Respiratorysystem

Nasalcavity

Bloodvessels

Pharynx

Larynx

Trachea

Bronchus

Figure 20.10_2

Integumentary system

Figure 20.10_3

Cartilage

Skeletal system

Figure 20.10_4

Muscular system

Skeletal muscles

Figure 20.10_5

Urinarysystem

Digestivesystem

Urinarybladder

Smallintestine

Largeintestine

Kidney

Ureter

Urethra

Esophagus

Stomach

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.

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

UterusVagina

Seminalvesicles

Prostategland

Vasdeferens

UrethraTestis

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.

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

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.

Figure 20.12

Epidermis

Dermis

Hypodermis(under the skin)

Adipose tissue

Blood vessels

Hair follicle

Oil gland

Sweatgland

Muscle

Sweatpore

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.

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.

– 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.

EXTERNAL EXCHANGE AND INTERNAL REGULATION

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.

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.

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.

Figure 20.13AEXTERNAL ENVIRONMENT

MouthFood

CO2 O2

ANIMAL

Digestivesystem

Respiratorysystem

Circulatorysystem

Urinarysystem

HeartInterstitialfluid

Bodycells

Intestine

Unabsorbedmatter (feces)

Metabolic wasteproducts (urine)

Nutrients

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

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

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

approximately 37°C

Figure 20.15_s3Sweat evaporates,cooling the body.

Blood vessels dilate.

Blood vessels constrict.

Brainactivateswarming mechanisms.Shivering generates

approximately 37°C

Figure 20.15_s4Sweat evaporates,cooling the body.

Blood vessels dilate.

Cooling mechanismsshut off.

Warming mechanismsshut off.

Blood vessels constrict.

Brainactivateswarming mechanisms.Shivering generates

Temperaturedecreases

Temperatureincreases

approximately 37°C

Figure 20.15_5

approximately 37°C

Temperaturedecreases

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

approximately 37°C

Temperatureincreases

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.

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.

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.

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

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

Figure 20.UN01_2

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

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fibrous connective tissue

epithelial cells

vital body function

structure fits function

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