Animal Tissues and Organ Systems Chapter 32

Impacts, Issues

Open 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

free surface of a simple epithelium basement membrane (material secreted by epithelial cells) underlying connective tissue

Fig. 32-3, p. 541

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

Simple squamous epithelium • Lines blood vessels, the heart, and air sacs of lungs • Allows substances to cross by diffusion

Fig. 32-4a, 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. 32-4b, 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

Fig. 32-4c, p. 541

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

cartilage at the end of long bone

compact bone tissue

spongy bone tissue

Fig. 32-6, p. 543

A Fluid Connective Tissue  Blood: Plasma, blood cells and platelets

white blood cell

red blood cell

platelet

Fig. 32-7, p. 543

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

cranial cavity spinal cavity

thoracic cavity diaphragm abdominal cavity

pelvic cavity Fig. 32-11a, p. 546

Dorsal Surface transverse midsagittal

ANTERIOR

POSTERIOR

frontal Ventral Surface

Fig. 32-11b, p. 546

SUPERIOR (of two body parts, the one closer to head) frontal plane (aqua)

midsagittal plane (green)

ANTERIOR (at or near front of body)

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

POSTERIOR (at or near back of body)

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

transverse plane (yellow)

Fig. 32-11c, p. 546

Animation: Human body cavities

Animation: Directional terms and planes of symmetry

Eleven Vertebrate Organ Systems

Eleven Vertebrate Organ Systems

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

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

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

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

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

Endocrine System Hormonally controls body functioning; with nervous system integrates shortand long-term activities. (Male testes added.) Fig. 32-12a, p. 547

Lymphatic System

Respiratory System Digestive 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.

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

Reproductive System 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. Fig. 32-12b, p. 547

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

hair epidermis

dermis

hypodermis

oil gland hair follicle blood vessels

sensory neuron

sweat gland smooth muscle Fig. 32-13a, p. 548

outer flattened epidermal cells

cells being flattened dividing cells

dermis Fig. 32-13b, p. 548

hair’s cuticle

one hair cell

keratin macrofibril

keratin polypeptide chain

Fig. 32-13c, p. 548

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

mucous gland

poison gland

pigmented cell Fig. 32-14b, p. 549

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

ABC video: A Saving Graft

ABC video: New Hands

Video: Stem Cells