animal tissues

Animal Tissues and Organ Systems

Chapter 32

Impacts, IssuesOpen or Close the Stem Cell Factories?

Only embryonic stem cells can differentiate into any specialized cell in the body; engineered stem cells are not yet safe for humans

Homeostasis in Animals

Body parts must interact to perform many tasks• Coordinate and control individual parts• Acquire and distribute raw materials to cells and

dispose of wastes• Protect tissues against injury or attack• Reproduce, nourish and protect offspring through

early growth and development• Maintain the internal environment (homeostasis)

32.1 Organization of Animal Bodies

Tissue• Interacting cells and extracellular substances that

carry out one or more specialized tasks

Organ• Structural unit of two or more tissues organized in

a specific way to carry out specific tasks

Organ systems• Two or more organs and other components

interacting in a common task

Animal Cells are United by Cell Junctions

Tight junctions• Prevent fluid from seeping between epithelial

cells; fluid must pass through cells

Adhering junctions• Hold cells together at distinct spots

Gap junctions• Permit ions and small molecules to pass from

cytoplasm of one cell to another

32.1 Key Concepts Animal Organization

All animals are multicelled, with cells joined by cell junctions

Typically, cells are organized in four tissue types: epithelial tissue, connective tissue, muscle tissue, and nervous tissue

Organs, which consist of a combination of tissues, interact in organ systems

32.2 Epithelial Tissue

Epithelium (epithelial tissue)• A sheet of cells that covers the body’s outer

surface and lines its internal ducts and cavities

Basement membrane• A secreted extracellular matrix that attaches the

epithelium to the underlying tissue

Microvilli• Fingerlike projections of absorptive epithelia

General Structure of Simple Epithelium

Fig. 32-3, p. 541

free surface of a simple epithelium

basement membrane (material secreted by epithelial cells)

underlying connective tissue

Describing Epithelial Tissues

Thickness• Simple epithelium: One cell thick• Stratified epithelium: More than one cell thick

Cell shape• Squamous: Flattened• Cuboidal: Cube-shaped• Columnar: Tall

Types of Epithelial Tissues

Fig. 32-4a, p. 541

Simple squamous epithelium

• Lines blood vessels, the heart, and air sacs of lungs

• Allows substances to cross by diffusion

Fig. 32-4b, p. 541

Fig. 32-4b, p. 541

Simple cuboidal epithelium

• Lines kidney tubules, ducts of some glands, oviducts

• Functions in absorption an secretion, movement of materials

Fig. 32-4c, p. 541

Fig. 32-4c, p. 541

Simple columnar epithelium mucus-secreting gland cell

• Lines some airways, parts of the gut

• Functions in absorption and secretion, protection

Glandular Epithelium

Glands• Organs that release substances onto the skin, or

into a body cavity or interstitial fluid

Exocrine glands (glands with ducts)• Deliver secretions to an external or internal

surface (saliva, milk, earwax, digestive enzymes)

Endocrine glands (no ducts)• Secrete hormones which are carried in blood

32.3 Connective Tissues

Connective tissues consist of cells and the extracellular matrix they secrete

Connective tissues connect body parts and provide structural and functional support to other body tissues

Soft Connective Tissues

Loose connective tissue• Fibroblasts secrete a matrix of complex

carbohydrates with fibers dispersed widely through the matrix

Dense connective tissue (dense collagen fibers)• Dense irregular: Supports skin, internal organs• Dense regular: Ligaments and tendons

Specialized Connective Tissues

Cartilage: Rubbery extracellular matrix, supports and cushions bones

Adipose tissue: Fat filled cells, stores energy, cushions and protect organs

Bone: Rigid support, muscle attachment, protection, mineral storage, blood production

Connective Tissues

Connective Tissues

Fig. 32-5a, p. 542

Fig. 32-5b, p. 542

Fig. 32-5c, p. 542

Fig. 32-5d, p. 542

Fig. 32-5e, p. 543

Fig. 32-5f, p. 543

Cartilage and Bone Tissue

Fig. 32-6, p. 543

cartilage at the end of long bone

compact bone tissue

spongy bone tissue

A Fluid Connective Tissue

Blood: Plasma, blood cells and platelets

Fig. 32-7, p. 543

white blood cell

red blood cell

platelet

32.4 Muscle Tissues

Muscle tissue is made up of cells that contract when stimulated, requires ATP energy

Three Types of Muscle Tissues

Skeletal muscle tissue• Moves the skeleton (voluntary)• Long, striated cells with many nuclei

Cardiac muscle tissue• Heart muscle (involuntary)• Striated cells with single nuclei

Smooth muscle tissue• In walls of hollow organs (involuntary)• No striations, single nuclei

32.5 Nervous Tissue

Nervous tissue• Consists of specialized signaling cells (neurons)

and cells that support them (neuroglial cells)

Nervous tissue detects internal and external stimuli, and coordinates responses to stimuli

Neurons

Neurons• Excitable cells with long cytoplasmic extensions• Send and receive electrochemical signals

Three types of neurons• Sensory neurons are excited by specific stimuli• Interneurons integrate sensory information• Motor neurons relay commands from brain and

spinal cord to muscles and glands

A Motor Neuron

Coordination of Nervous Tissue and Skeletal Muscle

32.2-32.5 Key Concepts Types of Animal Tissues

Epithelial tissue covers the body’s surface and lines its internal tubes

Connective tissue provides support and connects body parts

Muscle tissue moves the body and its parts

Nervous tissue detects internal and external stimuli and coordinates responses

32.6 Overview of Major Organ Systems

In vertebrates, organs arise from three embryonic germ layers• Ectoderm (outermost layer) forms nervous tissue

and epithelium of skin• Mesoderm (middle layer) forms muscle,

connective tissue, and lining of body cavities• Endoderm (innermost layer) forms epithelium of

gut and lungs

Body Cavities and Directional Terms

Body Cavities and Directional Terms

Body Cavities and Directional Terms

Fig. 32-11a, p. 546

cranial cavity

spinal cavity

thoracic cavity

diaphragm

abdominal cavity

pelvic cavity

Fig. 32-11b, p. 546

Dorsal Surface

transverse

midsagittal

ANTERIOR POSTERIOR

frontal

Ventral Surface

Fig. 32-11c, p. 546

SUPERIOR (of two body parts,

the one closer to head)distal (farthest from trunk or from origin of a body part)

frontal plane (aqua)

midsagittal plane (green)

proximal (closest to trunk or to point of origin of a body part)

ANTERIOR (at or near front of body) POSTERIOR

(at or near back of body)

transverse plane (yellow)INFERIOR

(of two body parts, the one farthest from head)

Animation: Human body cavities

Animation: Directional terms and planes of symmetry

Eleven Vertebrate Organ Systems

Eleven Vertebrate Organ Systems

Fig. 32-12a, p. 547

Integumentary System

Nervous System

Muscular System

Skeletal System

Circulatory System

Endocrine System

Protects body from injury, dehydration, and some pathogens; controls its temperature; excretes certain wastes; receives some external stimuli.

Detects external and internal stimuli; controls and coordinates responses to stimuli; integrates all organ system activities.

Moves body and its internal parts; maintains posture; generates heat by increases in metabolic activity.

Supports and protects body parts; provides muscle attachment sites; produces red blood cells; stores calcium, phosphorus.

Rapidly transports many materials to and from interstitial fluid and cells; helps stabilize internal pH and temperature.

Hormonally controls body functioning; with nervous system integrates short- and long-term activities. (Male testes added.)

Fig. 32-12b, p. 547

Lymphatic System Respiratory System Digestive System Urinary System Reproductive System

Collects and returns some tissue fluid to the bloodstream; defends the body against infection and tissue damage.

Rapidly delivers oxygen to the tissue fluid that bathes all living cells; removes carbon dioxide wastes of cells; helps regulate pH.

Ingests food and water; mechanically, chemically breaks down food and absorbs small molecules into internal environment; eliminates food residues.

Maintains the volume and composition of internal environment; excretes excess fluid and bloodborne wastes.

Female: Produces eggs; after fertilization, affords a protected, nutritive environment for the development of new individuals. Male: Produces and transfers sperm to the female. Hormones of both systems also influence other organ systems.

Animation: Human organ systems

32.6 Key Concepts Organ Systems

Vertebrate organ systems compartmentalize the tasks of survival and reproduction for the body as a whole

Different systems arise from ectoderm, mesoderm, and endoderm, the primary tissue layers that form in the early embryo

32.7 Vertebrate Skin—Example of an Organ System

Skin is the body’s interface with the environment• Sensory receptors, barrier against pathogens,

internal temperature control, water conservation

Vertebrate skin is made up of all four tissue types arranged in two layers: • Outer epidermis contain keratinocytes• Deeper dermis contains nerves, blood and lymph

vessels, hair follicles and glands

Skin Structure

Skin Structure

Skin Structure

Fig. 32-13a, p. 548

hair

epidermis

dermis

hypodermis

sensory neuronoil gland

hair follicle sweat gland

blood vessels smooth muscle

Fig. 32-13b, p. 548

outer flattened epidermal cells

cells being flattened

dividing cells

dermis

Fig. 32-13c, p. 548

hair’s cuticle

one hair cell

keratin macrofibril

keratin polypeptide chain

Animation: Structure of human skin

Animation: Hair fine structure

Frog Skin

Amphibians may have glands that secrete mucus, distasteful chemicals, or poisons• Pigmented cells in dermis warn predators

Fig. 32-14b, p. 549

Fig. 32-14b, p. 549

mucous gland poison gland pigmented cell

Sunlight and Human Skin

Melanocytes in skin make a brown pigment (melanin) which affects skin color and tanning

Melanin protects against UV radiation• A little UV promotes vitamin D production• A lot of UV damages DNA and promotes cancer

32.8 Farming Skin

Commercially grown skin substitutes are already in use for treatment of chronic wounds

Skin may be a source of stem cells that could be used to grow other organs

32.7-32.8 Key Concepts A Closer Look at Skin

Skin is an example of an organ system

It includes epithelial layers, connective tissue, adipose tissue, glands, blood vessels, and sensory receptors

It helps protect the body, conserve water, control temperature, excrete wastes, and detect external stimuli

Animation: Altering hair structure

Animation: Cell junctions

Animation: Functional zones of a motor neuron

Animation: Muscle tissues

Animation: Organization of animal cells

Animation: Soft connective tissues

Animation: Specialized connective tissues

Animation: Structure of an epithelium

Animation: Types of simple epithelium

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