4 – Lab The Tissue Level of Organization

© 2012 Pearson Education, Inc.

PowerPoint® Lecture Presentations prepared byJason LaPresLone Star College—North Harris

4 – Lab The Tissue Level of Organization

1


An Introduction to Tissues

• Learning Outcomes• 4-1 Identify the four major types of tissues in the

body and describe their roles.

• 4-2 Discuss the types and functions of epithelial tissue.

• 4-3 Describe the relationship between form and function for each type of epithelium.

2



• Learning Outcomes• 4-4 Compare the structures and functions of the

various types of connective tissues.

• 4-5 Describe how cartilage and bone function as a supporting connective tissue.

• 4-6 Explain how epithelial and connective tissues combine to form four types of tissue

membranes, and specify the functions of each.

• 4-7 Describe how connective tissue establishes the framework of the body.

3



• Learning Outcomes• 4-8 Describe the three types of muscle tissue and

the special structural features of each type.

• 4-9 Discuss the basic structure and role of neural tissue

• 4-10 Describe how injuries affect the tissues of the body.

• 4-11 Describe how aging affects the tissues of the body.

4



• Tissues

• Structures with discrete structural and functional properties

• Tissues in combination form organs, such as the heart or liver

• Organs can be grouped into 11 organ systems

5


4-1 Four Types of Tissue

• Tissue

• Are collections of cells and cell products that perform specific, limited functions

• Four types of tissue

1. Epithelial tissue

2. Connective tissue

3. Muscle tissue

4. Neural tissue

6



• Epithelial Tissue• Covers exposed surfaces

• Lines internal passageways

• Forms glands

• Connective Tissue• Fills internal spaces

• Supports other tissues

• Transports materials

• Stores energy 7



• Muscle Tissue• Specialized for contraction

• Skeletal muscle, heart muscle, and walls of hollow organs

• Neural Tissue• Carries electrical signals from one part of the body

to another

8


4-2 Epithelial Tissue

• Epithelia

• Layers of cells covering internal or external surfaces

• Glands

• Structures that produce secretions

9



• Characteristics of Epithelia

• Cellularity (cell junctions)

• Polarity (apical and basal surfaces)

• Attachment (basement membrane or basal lamina)

• Avascularity

• Regeneration

10


Figure 4-1 The Polarity of Epithelial Cells

Cilia

MicrovilliApicalsurface

Golgiapparatus

Nucleus

MitochondriaBasement membraneBasolateralsurfaces 11



• Functions of Epithelial Tissue

1. Provide Physical Protection

2. Control Permeability

3. Provide Sensation

4. Produce Specialized Secretions (glandular epithelium)

12


4-3 Classification of Epithelia

• Singular = Epithelium; Plural = Epithelia

• Classes of Epithelia

1. Based on shape

• Squamous epithelia — thin and flat

• Cuboidal epithelia — square shaped

• Columnar epithelia — tall, slender rectangles

2. Based on layers

• Simple epithelium — single layer of cells

• Stratified epithelium — several layers of cells 13


Table 4-1 Classifying Epithelia

14


Table 4-1 Classifying Epithelia

15



• Squamous Epithelia• Simple squamous epithelium

• Absorption and diffusion

• Mesothelium

• Lines body cavities

• Endothelium

• Lines heart and blood vessels

16


Figure 4-3a Squamous Epithelia

Simple Squamous Epithelium

Lining of peritoneal cavityConnective tissue

Nucleus

Cytoplasm

LOCATIONS: Mesothelia lining ventral body cavities; endothelia lining heartand blood vessels; portions of kidney tubules (thin sections of nephron loops); inner lining of cornea; alveoli of lungs

FUNCTIONS: Reduces friction; controls vessel permeability; performsabsorption and secretion

LM 238

17


18



• Squamous Epithelia

• Stratified squamous epithelium

• Protects against attacks

• Keratin protein adds strength and water resistance

19


Figure 4-3b Squamous Epithelia

LOCATIONS: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina

FUNCTIONS: Provides physical protection against abrasion, pathogens, and chemical attack

Surface of tongue

Squamoussuperficial cells

Stem cellsBasementmembraneConnective

tissueLM 310

Stratified Squamous Epithelium

20


21



• Cuboidal Epithelia• Simple cuboidal epithelium

• Secretion and absorption

• Stratified cuboidal epithelia

• Sweat ducts and mammary ducts

22


Figure 4-4a Cuboidal and Transitional Epithelia

Simple Cuboidal Epithelium

LOCATIONS: Glands; ducts;portions of kidney tubules; thyroidgland

FUNCTIONS: Limited protection,secretion, absorption

Kidney tubule

Connectivetissue

Nucleus

Cuboidalcells

Basementmembrane

LM 650

23


Figure 4-4b Cuboidal and Transitional Epithelia

LOCATIONS: Lining of some ducts(rare)

FUNCTIONS: Protection, secretion,absorption

LM 500

Lumenof duct

Sweat gland duct

Stratifiedcuboidal

cellsBasementmembrane

Nuclei

Connectivetissue

Stratified Cuboidal Epithelium

24


Simple Cuboidal Epithelium

25



• Transitional Epithelium• Tolerates repeated cycles of stretching and recoiling

and returns to its previous shape without damage

• Appearance changes as stretching occurs

• Situated in regions of the urinary system (e.g., urinary bladder)

26


Figure 4-4c Cuboidal and Transitional Epithelia

Transitional Epithelium

FUNCTIONS: Permitsexpansion and recoilafter stretching

LOCATIONS: Urinarybladder; renal pelvis;ureters

LM 400

Urinary bladder

LM 400

Empty bladder

Epithelium(relaxed)

Connective tissue andsmooth muscle layers

Epithelium(stretched)

Connective tissue andsmooth muscle layers

Basement membrane

Full bladder

Basement membrane

LM 400

27


Transitional Epithelium

28



• Columnar Epithelia

• Simple columnar epithelium

• Absorption and secretion

• Pseudostratified columnar epithelium

• Cilia movement

• Stratified columnar epithelium

• Protection

29


Figure 4-5a Columnar Epithelia

LOCATIONS: Lining ofstomach, intestine, gallbladder,uterine tubes, and collectingducts of kidneysFUNCTIONS: Protection,secretion, absorption

Simple Columnar Epithelium

Microvilli

Cytoplasm

Intestinal lining

Basementmembrane

Looseconnective tissue LM 350

Nucleus

30


Simple Columnar Epithelium

31


Figure 4-5b Columnar Epithelia

LOCATIONS: Lining ofnasal cavity, trachea, andbronchi; portions of malereproductive tract

FUNCTIONS: Protection,secretion, move mucuswith cilia

Pseudostratified Ciliated Columnar Epithelium

Cilia

Trachea

Cytoplasm

Nuclei

Basementmembrane

Looseconnective tissue

LM 350

32


Pseudostratified Ciliated Columnar Epithelium

33


Figure 4-5c Columnar Epithelia

LOCATIONS: Small areas ofthe pharynx, epiglottis, anus,mammary glands, salivarygland ducts, and urethra

FUNCTION: Protection

Stratified Columnar Epithelium

Salivary gland duct

Deeper basalcells

Looseconnective tissue

Superficialcolumnar cells

Cytoplasm

Nuclei

Basementmembrane

LumenLumen

LM 175

34



• Glandular Epithelia

• Endocrine glands

• Release hormones

• Into interstitial fluid

• No ducts

• Exocrine glands

• Produce secretions

• Onto epithelial surfaces

• Through ducts35



• Glandular Epithelia

• Gland Structure

• Unicellular glands

• Mucous (goblet) cells are the only unicellular exocrine glands

• Scattered among epithelia

• For example, in intestinal lining

36



• Gland Structure • Multicellular glands

1. Structure of the duct

• Simple (undivided)

• Compound (divided)

2. Shape of secretory portion of the gland

• Tubular (tube shaped)

• Alveolar or acinar (blind pockets)

3. Relationship between ducts and glandular areas

• Branched (several secretory areas sharing one duct) 37


Figure 4-7 A Structural Classification of Exocrine Glands

SIMPLE GLANDS

Glandcells

SIMPLETUBULAR

SIMPLE COILEDTUBULAR

Examples:

Examples:

Examples:• Intestinal glands • Merocrine sweat

stage in developmentof simple branchedglands

SIMPLE BRANCHEDTUBULAR

Examples:• Gastric glands• Mucous glands

• Not found in adult; a

SIMPLE ALVEOLAR(ACINAR)

SIMPLE BRANCHEDALVEOLAR

Examples:• Sebaceous (oil)

glandsof esophagus,tongue, duodenum

glands

Duct

38


Figure 4-7 A Structural Classification of Exocrine Glands

COMPOUND GLANDS

COMPOUNDTUBULAR

COMPOUND ALVEOLAR(ACINAR)

COMPOUND TUBULOALVEOLAR

Examples:• Mucous glands (in mouth) Examples:• Bulbo-urethral glands (in

male reproductive system)

tubules)

• Mammary glandsExamples:

• Salivary glands• Glands of respiratory

passages• Testes (seminiferous• Pancreas

39


4-4 Connective Tissue

• Characteristics of Connective Tissue

1. Specialized cells

2. Solid extracellular protein fibers

3. Fluid extracellular ground substance

• The Extracellular Components of Connective Tissue (Fibers and Ground Substance)

• Make up the matrix• Majority of tissue volume

• Determines specialized function40



• Functions of Connective Tissue

• Establishing a structural framework for the body

• Transporting fluids and dissolved materials

• Protecting delicate organs

• Supporting, surrounding, and interconnecting other types of tissue

• Storing energy reserves, especially in the form of triglycerides

• Defending the body from invading microorganisms41



• Classification of Connective Tissues

1. Connective tissue proper

• Connect and protect

2. Fluid connective tissues

• Transport

3. Supporting connective tissues

• Structural strength

42



• Categories of Connective Tissue Proper

• Loose connective tissue

• More ground substance, fewer fibers

• For example, fat (adipose tissue)

• Dense connective tissue

• More fibers, less ground substance

• For example, tendons

43



• Fibroblasts

• Fibrocytes

• Adipocytes

• Mesenchymal cells

• Macrophages

• Mast cells

• Lymphocytes

• Microphages

• Melanocytes

Connective Tissue Proper Cell Populations

44



• Fibroblasts• The most abundant cell type

• Found in all connective tissue proper

• Secrete proteins and hyaluronan (cellular cement)

• Fibrocytes• The second most abundant cell type

• Found in all connective tissue proper

• Maintain the fibers of connective tissue proper

45



• Adipocytes• Fat cells

• Each cell stores a single, large fat droplet

• Mesenchymal Cells• Stem cells that respond to injury or infection

• Differentiate into fibroblasts, macrophages, etc.

46



• Macrophages• Large, amoeba-like cells of the immune system

• Eat pathogens and damaged cells

• Fixed macrophages stay in tissue

• Free macrophages migrate

47



• Mast Cells• Stimulate inflammation after injury or infection

• Release histamine and heparin

• Basophils are leukocytes (white blood cells) that also contain histamine and heparin

48



• Lymphocytes• Specialized immune cells in lymphatic (lymphoid)

system

• For example, lymphocytes may develop into plasma cells (plasmocytes) that produce antibodies

49



• Microphages• Phagocytic blood cells

• Respond to signals from macrophages and mast cells

• For example, neutrophils and eosinophils

• Melanocytes• Synthesize and store the brown pigment melanin

50



• Connective Tissue Fibers

1. Collagen fibers

2. Reticular fibers

3. Elastic fibers

51



• Collagen Fibers

• Most common fibers in connective tissue proper

• Long, straight, and unbranched

• Strong and flexible

• Resist force in one direction

• For example, tendons and ligaments

52



• Reticular Fibers

• Network of interwoven fibers (stroma)

• Strong and flexible

• Resist force in many directions

• Stabilize functional cells (parenchyma) and

structures

• For example, sheaths around organs

53



• Elastic Fibers

• Contain elastin

• Branched and wavy

• Return to original length after stretching

• For example, elastic ligaments of vertebrae

54



• Ground Substance

• Is clear, colorless, and viscous

• Fills spaces between cells and slows pathogen

movement

55


Figure 4-8 The Cells and Fibers of Connective Tissue Proper

Reticularfibers

MelanocyteFixed

macrophage

Plasma cell

Bloodin vessel

Adipocytes(fat cells)

Groundsubstance

Mast cell

Elasticfibers

Freemacrophage

Collagenfibers

Fibroblast

Mesenchymalcell

Lymphocyte

56


Figure 4-8 The Cells and Fibers of Connective Tissue Proper

Elasticfibers

Collagenfibers

Fibroblast

Freemacrophage

Connective tissue proper LM 50257



• Embryonic Connective Tissues

• Are not found in adults

• Mesenchyme (embryonic stem cells)

• The first connective tissue in embryos

• Mucous connective tissue

• Loose embryonic connective tissue

58


Areolar or Loose Connective Tissue

59


Figure 4-9a Connective Tissues in Embryos

Mesenchymalcells

Mesenchyme

This is the first connectivetissue to appear in an embryo.

LM 136

60


Figure 4-9b Connective Tissues in Embryos

Mesenchymalcells

Blood vessel

Mucous connective tissue(Wharton’s jelly)

LM 136

This sample was taken fromthe umbilical cord of a fetus.

61



• Loose Connective Tissues

• The “packing materials” of the body

• Three types in adults

1. Areolar

2. Adipose

3. Reticular

62



• Areolar Tissue

• Least specialized

• Open framework

• Viscous ground substance

• Elastic fibers

• Holds blood vessels and capillary beds

• For example, under skin (subcutaneous layer)

63



• Adipose Tissue• Contains many adipocytes (fat cells)

• 2 types of adipose tissue

1. White fat

2. Brown fat

64



• White fat• Most common • Stores fat• Absorbs shocks• Slows heat loss (insulation)

• Brown fat• More vascularized • Adipocytes have many mitochondria• When stimulated by nervous system, fat breakdown accelerates,

releasing energy • Absorbs energy from surrounding tissues

65



• Adipose Tissue

• Adipose cells

• Adipocytes in adults do not divide

• Expand to store fat

• Shrink as fats are released

• Mesenchymal cells divide and differentiate

• To produce more fat cells

• When more storage is needed

66


Adipose Tissue

67



• Reticular Tissue

• Provides support

• Complex, three-dimensional network

• Supportive fibers (stroma)

• Support functional cells (parenchyma)

• Reticular organs

• Spleen, liver, lymph nodes, and bone marrow

68


Figure 4-10a Adipose and Reticular Tissues

Adipose Tissue

LOCATIONS: Deep to the skin,especially at sides, buttocks,breasts; padding around eyesand kidneysFUNCTIONS: Providespadding and cushionsshocks; insulates(reduces heat loss);stores energy

Adipose tissue

Adipocytes(white adipose

cells)

LM 300

69


Figure 4-10b Adipose and Reticular Tissues

Reticular Tissue

FUNCTIONS: Provides supportingframework

LOCATIONS: Liver, kidney, spleen,lymph nodes, and bone marrow

Reticular tissuefrom liver

Reticular Tissue

Reticular fibers

LM 375

70


Reticular Tissue

71



• Dense Connective Tissues

• Connective tissues proper, tightly packed with high

numbers of collagen or elastic fibers

• Dense regular connective tissue

• Dense irregular connective tissue

• Elastic tissue

72


Dense Regular Connective Tissue

73



• Dense Regular Connective Tissue

• Tightly packed, parallel collagen fibers

• Tendons attach muscles to bones

• Ligaments connect bone to bone and stabilize organs

• Aponeuroses attach in sheets to large, flat muscles

74


Figure 4-11a Dense Connective Tissues

Dense Regular Connective Tissue

Collagenfibers

Fibroblastnuclei

Tendon LM 440

LOCATIONS: Between skeletalmuscles and skeleton (tendonsand aponeuroses); betweenbones or stabilizing positionsof internal organs (ligaments);covering skeletal muscles;deep fasciae

FUNCTIONS: Providesfirm attachment; conductspull of muscles; reducesfriction between muscles;stabilizes relative positionsof bones

75



• Dense Irregular Connective Tissue• Interwoven networks of collagen fibers

• Layered in skin

• Around cartilages (perichondrium)

• Around bones (periosteum)

• Form capsules around some organs (e.g., liver, kidneys)

76


Figure 4-11b Dense Connective Tissues

Collagenfiber

bundles

Deep dermis LM 111

Dense Irregular Connective Tissue

LOCATIONS: Capsules ofvisceral organs; periosteaand perichondria; nerveand muscle sheaths; dermisFUNCTIONS: Providesstrength to resist forcesapplied from manydirections; helpsprevent overexpansionof organs such asthe urinary bladder

77



• Elastic Tissue

• Made of elastic fibers

• For example, elastic ligaments of spinal vertebrae

78


Figure 4-11c Dense Connective Tissues

Elasticfibers

Fibroblastnuclei

Elastic ligament

Elastic Tissue

LOCATIONS: Between vertebraeof the spinal column (ligamentumflavum and ligamentum nuchae);ligaments supporting penis;ligaments supporting transitionalepithelia; in blood vessel walls FUNCTIONS: Stabilizespositions of vertebrae andpenis; cushions shocks;permits expansion andcontraction of organs

LM 887

79


Elastic Tissue

80



• Fluid Connective Tissues

• Blood and lymph

• Watery matrix of dissolved proteins

• Carry specific cell types (formed elements)

• Formed elements of blood

• Red blood cells (erythrocytes)

• White blood cells (leukocytes)

• Platelets81



• Fluid Elements of Connective Tissues

• Extracellular

• Plasma

• Interstitial fluid

• Lymph

82


Figure 4-12 Formed Elements of the Blood

Red blood cells

Red blood cells account for roughlyhalf the volume ofwhole blood andgive blood its color.

Red blood cells, orerythrocytes(e-RITH-ro-sıts), areresponsible for the transport of oxygen (and, to a lesser degree, of carbon dioxide) in the blood.

¯ ¯

83



White blood cells

Eosinophil

Neutrophil

Basophil

White blood cells, or leukocytes(LOO-ko-sıts; leuko-, white), help defend the body from infection and disease.

¯ ¯

Eosinophils and neutro-phils are phagocytes. Ba-sophils promote inflamma-tion much like mast cells in other connective tissues.

Lymphocytes are un-common in the bloodbut they are the domi-nant cell type in lymph,the second type of fluid connective tissue.

Monocytesare phagocytessimilar to thefree macro-phages inother tissues.

84



PlateletsPlatelets aremembrane-enclosedpackets of cytoplasmthat function in bloodclotting.

These cell fragmentsare involved in theclotting responsethat seals leaks indamaged or brokenblood vessels.

85



• Lymph

• Extracellular fluid

• Collected from interstitial space

• Monitored by immune system

• Transported by lymphatic (lymphoid) system

• Returned to venous system

86



• Fluid Tissue Transport Systems

• Cardiovascular system (blood)

• Arteries

• Capillaries

• Veins

• Lymphatic (lymphoid) system (lymph)

• Lymphatic vessels

87


4-5 Supporting Connective Tissues

• Support Soft Tissues and Body Weight

• Cartilage

• Gel-type ground substance

• For shock absorption and protection

• Bone

• Calcified (made rigid by calcium salts, minerals)

• For weight support

88



• Cartilage Matrix

• Proteoglycans derived from chondroitin sulfates

• Ground substance proteins

• Chondrocytes (cartilage cells) surrounded by

lacunae (chambers)

89



• Cartilage Structure

• No blood vessels

• Chondrocytes produce antiangiogenesis factor

• Perichondrium

• Outer, fibrous layer (for strength)

• Inner, cellular layer (for growth and maintenance)

90


Figure 4-13a The Growth of Cartilage

Interstitial growth

Chondrocyte undergoes divisionwithin a lacuna surrounded bycartilage matrix.

As daughter cells secrete additional matrix, theymove apart, expanding the cartilage from within.

LacunaChondrocyte

MatrixNew matrix

91


Figure 4-13b The Growth of Cartilage

Appositional growth

As the matrix enlarges, morechondroblasts are incorporated;they are replaced by divisions ofstem cells in the perichondrium.

These immaturechondroblasts secretenew matrix.

New matrix

ImmaturechondrocyteOlder matrixMaturechondrocyte

FibroblastDividing stem cell

Perichondrium

Cells in the cellular layerof the perichondriumdifferentiate intochondroblasts.

Chondroblasts

92



• Types of Cartilage

1. Hyaline cartilage

2. Elastic cartilage

3. Fibrocartilage (fibrous cartilage)

93



• Hyaline Cartilage

• Stiff, flexible support

• Reduces friction between bones

• Found in synovial joints, rib tips, sternum, and trachea

• Elastic Cartilage

• Supportive but bends easily

• Found in external ear and epiglottis 94



• Fibrocartilage (Fibrous Cartilage)

• Limits movement

• Prevents bone-to-bone contact

• Pads knee joints

• Found between pubic bones and intervertebral discs

95


Figure 4-14a Types of Cartilage

Hyaline Cartilage

LOCATIONS: Between tips of ribs and bones of sternum; covering bone surfaces at synovial joints; supporting larynx (voice box), trachea, and bronchi; forming part of nasal septumFUNCTIONS: Provides stiff butsomewhat flexible support;reduces frictionbetween bonysurfaces

Hyaline cartilageLM 500

Matrix

Chondrocytesin lacunae

96


Hyaline Cartilage

97


Figure 4-14b Types of Cartilage

Elastic CartilageLOCATIONS: Auricle of externalear; epiglottis; auditory canal;cuneiform cartilages of larynxFUNCTIONS: Provides support,but tolerates distortion withoutdamage andreturns tooriginal shape

Elastic cartilage

Elastic fibersin matrix

Chondrocytein lacuna

LM 358

98


Elastic Cartilage

99


Figure 4-14c Types of Cartilage

FibrocartilageLOCATIONS: Pads within kneejoint; between pubic bones ofpelvis; intervertebral discsFUNCTIONS: Resistscompression;prevents bone-to-bonecontact; limitsmovement

Fibrocartilage

Fibrousmatrix

Chondrocytesin lacunae

LM 400

100



• Bone or Osseous Tissue• Strong (calcified calcium salt deposits)• Resists shattering (flexible collagen fibers)

• Bone Cells or Osteocytes• Arranged around central canals within matrix• Small channels through matrix (canaliculi) access

blood supply

• Periosteum • Covers bone surfaces• Fibrous layer• Cellular layer 101


Figure 4-15 Bone

Canaliculi

Osteocytesin lacunae

Matrix

Central canal

Blood vessels

LM 375

Osteon

Osteon

Fibrouslayer

Cellularlayer

Periosteum

102


Bone

103


Table 4-2 A Comparison of Cartilage and Bone

104


4-8 Muscle Tissue

• Muscle Tissue• Specialized for contraction

• Produces all body movement

• Three types of muscle tissue

1. Skeletal muscle tissue• Large body muscles responsible for movement

2. Cardiac muscle tissue• Found only in the heart

3. Smooth muscle tissue• Found in walls of hollow, contracting organs (blood

vessels; urinary bladder; respiratory, digestive, and reproductive tracts) 105


4-8 Muscle Tissue

• Classification of Muscle Cells

• Striated (muscle cells with a banded appearance)

• Nonstriated (not banded; smooth)

• Muscle cells can have a single nucleus

• Muscle cells can be multinucleate

• Muscle cells can be controlled voluntarily (consciously)

• Muscle cells can be controlled involuntarily

(automatically)106


4-8 Muscle Tissue

• Skeletal Muscle Cells

• Long and thin

• Usually called muscle fibers

• Do not divide

• New fibers are produced by stem cells (myosatellite

cells)

107


Figure 4-18a Muscle Tissue

Skeletal Muscle Tissue

Skeletal muscle

Cells are long, cylindrical, striated, and multinucleate.LOCATIONS: Combinedwith connective tissuesand neural tissue inskeletal musclesFUNCTIONS: Moves orstabilizes the position ofthe skeleton; guardsentrances and exits tothe digestive,respiratory, and urinarytracts; generates heat;protects internal organs

Nuclei

Musclefiber

Striations

LM 180

108


Skeletal Muscle

109


4-8 Muscle Tissue

• Cardiac Muscle Cells

• Called cardiocytes

• Form branching networks connected at intercalated discs

• Regulated by pacemaker cells

• Smooth Muscle Cells

• Small and tapered

• Can divide and regenerate

110


Figure 4-18b Muscle Tissue

Cardiac Muscle Tissue

Cardiac muscle

Cells are short, branched,and striated, usually with asingle nucleus; cells areinterconnected byintercalated discs.

FUNCTIONS:Circulates blood;maintains blood(hydrostatic) pressure

LOCATION: Heart

LM 450

Nucleus

Cardiacmuscle

cells

Intercalateddiscs

Striations

111


Cardiac Muscle Tissue

112


Figure 4-18c Muscle Tissue

Smooth muscle

Cells are short, spindle-shaped, andnonstriated, with a single, centralnucleus.LOCATIONS: Found inthe walls of blood vesselsand in digestive, respiratory,urinary, and reproductive organs

FUNCTIONS: Moves food,urine, and reproductive tractsecretions; controlsdiameter of respiratorypassageways; regulatesdiameter of blood vessels

LM 235

Nucleus

Smoothmuscle

cell

Smooth Muscle Tissue

113


Smooth Muscle Tissue

114


4-9 Neural Tissue

• Neural Tissue

• Also called nervous or nerve tissue

• Specialized for conducting electrical impulses

• Rapidly senses internal or external environment

• Processes information and controls responses

• Neural tissue is concentrated in the central nervous system

• Brain

• Spinal cord115


Neural Tissue

116


4-9 Neural Tissue

• Two Types of Neural Cells

1. Neurons

• Nerve cells

• Perform electrical communication

2. Neuroglia

• Supporting cells

• Repair and supply nutrients to neurons

117


4-9 Neural Tissue

• Cell Parts of a Neuron

• Cell body

• Contains the nucleus and nucleolus

• Dendrites

• Short branches extending from the cell body

• Receive incoming signals

• Axon (nerve fiber)

• Long, thin extension of the cell body

• Carries outgoing electrical signals to their destination 118


Figure 4-19 Neural Tissue

NEURONS NEUROGLIA (supporting cells)

• Maintain physical structure

• Repair tissue framework

• Perform phagocytosis

• Regulate the composition of theinterstitial fluid surrounding neurons

of tissues

after injury

• Provide nutrients to neurons

Axon

NucleolusNucleusof neuron

Dendrites(contacted byother neurons)

Axon (conductsinformation toother cells)

Cell body

Dendrites

MitochondrionNucleus

Microfibrils andmicrotubules

Nucleolus

Cell body (contains nucleusand major organelles) A representative neuron

(sizes and shapes vary widely)

Contact with other cells

Nuclei of neuroglia

LM 600

119



Axon

NucleolusNucleusof neuron

Cell body

Dendrites

Nuclei of neuroglia

LM 600

120



NEUROGLIA (supporting cells)

• Maintain physical structure

• Repair tissue framework

• Perform phagocytosis

• Regulate the composition of theinterstitial fluid surrounding neurons

of tissues

after injury

• Provide nutrients to neurons

121



Dendrites(contacted byother neurons)

Axon (conductsinformation toother cells)

MitochondrionNucleus

Microfibrils andmicrotubules

Nucleolus

Cell body (contains nucleusand major organelles) A representative neuron

(sizes and shapes vary widely)

Contact with other cells

122

Documents

4 – Lab The Tissue Level of Organization