Transcript Chapter_005.ppt

Chapter 5
Tissues
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Slide 1
Principal Types of Tissue (Table 5-1)

Epithelial tissue

Connective tissue

Muscle tissue

Nervous tissue
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Slide 2
Extracellular Matrix (ECM)

Complex, nonliving material between cells in
a tissue (Figure 5-1)

Some tissues have a large amount of ECM; other
tissues have hardly any ECM

Different kinds of components give ECM in
different tissues a variety of characteristics
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Slide 3
Extracellular Matrix (ECM)

Components (Table 5-2)

Water

Proteins
• Structural proteins


Collagen—strong, flexible protein fiber
Elastin—elastic fibers
• Includes glycoproteins—proteins with a few carbohydrate
attachments

Fibronectin and laminins help connect the ECM
components to cells by binding with integrins in plasma
membranes

Glycoprotein attachments also allow local communication
within a tissue
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Slide 4
Extracellular Matrix (ECM)

Components (cont.)

Proteoglycans
• Hybrid molecules that are mostly carbohydrates attached
to a protein backbone
• Examples: chondroitin sulfate, heparin, and hyaluronate
• Different proteoglycans give different characteristics to
ECM, such as thickness, shock absorption (Table 5-2)
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Slide 5
Extracellular Matrix (ECM)

Functions

Helps bind tissues together structurally
• ECM components bind to each other and to integrins in
plasma membranes of cells
• In some tissues, it is primarily intercellular junctions that
hold cells together

Allows local communication among ECM and
various cells—through connection via integrins
in plasma membranes
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Slide 6
Embryonic Development of Tissues

Primary germ layers (Figure 5-2)

Endoderm

Mesoderm

Ectoderm

Gastrulation—process of cell movement and
differentiation, which results in development
of primary germ layers

Histogenesis—the process by which the
primary germ layers differentiate into different
kinds of tissue
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Slide 7
Epithelial Tissue

Types and locations

Epithelium is divided into two types:
• Membranous (covering or lining) epithelium
• Glandular epithelium

Locations
• Membranous epithelium—covers the body and some of
its parts; lines the serous cavities, blood and lymphatic
vessels, and respiratory, digestive, and genitourinary
tracts
• Glandular epithelium—secretory units of endocrine and
exocrine glands
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Slide 8
Epithelial Tissue

Functions

Protection

Sensory functions

Secretion

Absorption

Excretion
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Slide 9
Epithelial Tissue

Generalizations about epithelial tissue

Limited amount of matrix material

Membranous type attached to a basement
membrane

Avascular

Cells are in close proximity, with many
desmosomes and tight junctions

Capable of reproducing itself
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Slide 10
Epithelial Tissue

Classification of epithelial tissue

Membranous (covering or lining) epithelium
(Table 5-3)
• Classification based on cell shape (Figure 5-3)

Squamous

Cuboidal

Columnar

Pseudostratified columnar
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Slide 11
Epithelial Tissue

Classification of epithelial tissue (cont.)

Classifications based on layers of cells (Table 5-4)
• Simple epithelium

Simple squamous epithelium (Figures 5-4 and 5-5)

One-cell layer of flat cells

Permeable to many substances

Examples: endothelium—lines blood vessels; mesothelium—pleura

Simple cuboidal epithelium (Figure 5-6)

One-cell layer of cuboidal cells

Found in many glands and ducts
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Slide 12
Epithelial Tissue
• Simple epithelium (cont.)

Simple columnar epithelium (Figure 5-7)

Single layer of tall, column-shaped cells

Cells often modified for specialized functions—e.g., goblet cells (secretion), cilia
(movement), microvilli (absorption)

Often lines hollow visceral structures

Pseudostratified columnar epithelium (Figure 5-8)

Columnar cells of differing heights

All cells rest on basement membrane but may not reach the free surface above

Cell nuclei at odd and irregular levels

Found lining air passages and segments of male reproductive system

Motile cilia and mucus are important modifications
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Slide 13
Epithelial Tissue
• Stratified epithelium

Stratified squamous (keratinized) epithelium

Multiple layers of flat, squamous cells (Figure 5-9)

Cells filled with keratin

Covers outer skin on body surface

Stratified squamous (nonkeratinized) epithelium
(Figure 5-10)

Lines vagina, mouth, and esophagus

Free surface is moist

Primary function is protection
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Slide 14
Epithelial Tissue
• Stratified epithelium (cont.)

Stratified cuboidal epithelium

Two or more rows of cells are typical

Basement membrane is indistinct

Located in sweat gland ducts and pharynx

Stratified columnar epithelium

Multiple layers of columnar cells

Only most superficial cells are typical in shape

Rare

Located in segments of male urethra and near anus
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Slide 15
Epithelial Tissue
• Stratified epithelium (cont.)

Stratified transitional epithelium (Figure 5-11)

Located in lining of hollow viscera subjected to stress
(e.g., urinary bladder)

Often 10 or more layers thick

Protects organ walls from tearing
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Slide 16
Epithelial Tissue

Glandular epithelium

Specialized for secretory activity

Exocrine glands—discharge secretions into ducts

Endocrine glands—“ductless” glands; discharge
secretions directly into the blood or interstitial fluid

Structural classification of exocrine glands
(Figure 5-12; Table 5-5)
• Multicellular exocrine glands are classified by the shape of their
ducts and the complexity of their duct system

Shapes include tubular and alveolar

Simple exocrine glands—only one duct leads to the surface

Compound exocrine glands—have two or more ducts
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Slide 17
Epithelial Tissue

Glandular epithelium (cont.)

Functional classification of exocrine glands (Figure 5-13)
• Apocrine glands

Secretory products collect near apex of cell and are secreted by pinching off the
distended end

Secretion process results in some damage to cell wall and some loss of
cytoplasm

Mammary glands are good examples of this secretory type
• Holocrine glands

Secretion products, when released, cause rupture and death of the cell

Sebaceous glands are holocrine
• Merocrine glands

Secrete directly through cell membrane

Secretion proceeds with no damage to cell wall and no loss of cytoplasm

Most prevalent gland type
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Slide 18
Connective Tissue

Functions, characteristics, and types

General function—connects, supports, transports,
and protects

General characteristics—extracellular matrix
(ECM) predominates in most connective tissues
and determines its physical characteristics;
consists of fluid, gel, or solid matrix, with or without
extracellular fibers (collagenous, reticular, and
elastic) and proteoglycans or other compounds
that thicken and hold together the tissue
(Figures 5-1 and 5-14)
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Slide 19
Connective Tissue

Four main types (Table 5-6):


Fibrous
• Loose, ordinary
• Cancellous bone
(areolar)
• Adipose

• Reticular
• Dense

Irregular

Regular
(collagenous and elastic)
Bone
• Compact bone

Cartilage
• Hyaline
• Fibrocartilage
• Elastic
Blood
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Slide 20
Connective Tissue

Fibrous connective tissue

Loose, ordinary (areolar) connective tissue
(Figure 5-15)
• One of the most widely distributed of all tissues
• Intercellular substance is prominent and consists of
collagenous and elastic fibers loosely interwoven and
embedded in soft, viscous ground substance
• Several kinds of cells present: notably, fibroblasts and
macrophages; also mast cells, plasma cells, fat cells,
and some white blood cells (Figure 5-16)
• Function—stretchy, flexible connection
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Slide 21
Connective Tissue


Adipose tissue (Figures 5-17 and 5-18)

Similar to loose connective tissue but contains mainly fat cells

Functions—protection, insulation, support, and food reserve
Reticular tissue (Figure 5-19)

Forms framework of spleen, lymph nodes, and bone marrow

Consists of network of branching reticular fibers with reticular
cells overlying them

Functions—defense against microorganisms and other injurious
substances; reticular meshwork filters out injurious particles, and
reticular cells phagocytose them
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Slide 22
Connective Tissue

Dense fibrous tissue
• Matrix consists mainly of fibers packed densely and
relatively few fibroblast cells

Irregular—fibers intertwine irregularly to form a thick mat (Figure 5-20)

Regular—bundles of fibers are arranged in regular, parallel rows
–
Collagenous—mostly collagenous fibers in ECM (Figure 5-21 and 5-22)
–
Elastic—mostly elastic fibers in ECM (Figure 5-23)
• Locations—composes structures that need great tensile
strength, such as tendons and ligaments; also dermis
and outer capsule of kidney and spleen
• Function—furnishes flexible connections that are strong
or stretchy
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Slide 23
Connective Tissue

Bone tissue

Highly specialized connective tissue type
• Cells—osteocytes—embedded in a calcified matrix
• Inorganic component of matrix accounts for 65%
of total bone tissue

Functions:
• Support
• Protection
• Point of attachment for muscles
• Reservoir for minerals
• Supports blood-forming tissue
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Slide 24
Connective Tissue

Compact bone (Figures 5-25 and 5-26)

Osteon (Haversian system)
•
•
•
•

Structural unity of bone
Spaces for osteocytes called lacunae
Matrix present in concentric rings called lamellae
Canaliculi are canals that join lacunae with the central Haversian canal
Cell types:
• Osteocyte—mature, inactive bone cell
• Osteoblast—active, bone-forming cell
• Osteoclast—bone-destroying cell

Formation (ossification) (Figure 5-24)
• In membranes—e.g., flat bones of skull
• From cartilage (endochondral)—e.g., long bones, such as the humerus
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Slide 25
Connective Tissue

Cancellous bone (Figures 5- 25 and 5-27)

Trabeculae—thin beams of bone

Supports red bone marrow
• Myeloid tissue—a type of reticular tissue
• Produces blood cells

Called spongy bone because of its spongelike
appearance
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Slide 26
Connective Tissue

Cartilage

Chondrocyte is only cell type present

Lacunae house cells, as in bone

Avascular—therefore, nutrition of cells depends on
diffusion of nutrients through matrix

Heals slowly after injury because of slow nutrient
transfer to the cells

Perichondrium is membrane that surrounds
cartilage
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Slide 27
Connective Tissue

Types

Hyaline (Figure 5-28)
• Appearance is shiny and translucent
• Most prevalent type of cartilage
• Located on the ends of articulating bones

Fibrocartilage (Figure 5-29)
•
•
•
•

Strongest and most durable type of cartilage
Matrix is semirigid and filled with strong, white fibers
Found in intervertebral disks and pubic symphysis
Serves as shock-absorbing material between bones at the knee (menisci)
Elastic (Figure 5-30)
• Contains many fine, elastic fibers
• Provides strength and flexibility
• Located in external ear and larynx
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Slide 28
Connective Tissue

Blood

A liquid tissue (Figure 5-31)

Contains neither ground substance nor fibers

Composition of whole blood
• Liquid fraction (plasma) is the matrix—55% of total blood
volume
• Formed elements contribute 45% of total blood volume

Red blood cells, erythrocytes

White blood cells, leukocytes

Platelets, thrombocytes
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Slide 29
Connective Tissue

Blood (cont.)

Functions
• Transportation
• Regulation of body temperature
• Regulation of body pH
• White blood cells destroy bacteria

Circulating blood tissue is formed in the red bone
marrow by a process called hematopoiesis; the
blood-forming tissue is sometimes called
hematopoietic tissue
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Slide 30
Muscle Tissue


Types (Table 5-7)

Skeletal, or striated voluntary (Figure 5-32)

Smooth, or nonstriated involuntary, or visceral
(Figures 5-33 and 5-34)

Cardiac, or striated involuntary (Figure 5-35)
Microscopic characteristics

Skeletal muscle—threadlike cells with many cross
striations and many nuclei per cell

Smooth muscle—elongated, narrow cells, no cross
striations, one nucleus per cell

Cardiac muscle—branching cells with intercalated disks
(formed by abutment of plasma membranes
of two cells)
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Slide 31
Nervous Tissue

Functions—rapid regulation and integration
of body activities

Specialized characteristics


Excitability

Conductivity
Organs

Brain

Spinal cord

Nerves
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Slide 32
Nervous Tissue

Cell types (Table 5-7)

Neuron—conducting unit of system (Figure 5-36)
• Cell body, or soma
• Processes


Axon (single process)—transmits nerve impulse away from
the cell body

Dendrites (one or more)—transmit nerve impulse toward
the cell body and axon
Neuroglia—special connecting, supporting,
coordinating cells that surround the neurons
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Slide 33
Tissue Repair





Tissues have a varying capacity to repair
themselves; damaged tissue regenerates
or is replaced by scar tissue
Regeneration—growth of new tissue
(Figure 5-37)
Scar—dense fibrous mass; unusually thick scar
is a keloid (Figure 5-38)
Epithelial and connective tissues have the
greatest ability to regenerate
Muscle and nervous tissues have a limited
capacity to regenerate
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Slide 34
Body Membranes


Thin tissue layers that cover surfaces, line cavities,
and divide spaces or organs (Figure 5-39, Table 5-8)
Epithelial membranes are most common type
(Figure 5-40)

Cutaneous membrane (skin)
• Primary organ of integumentary system
• One of the most important organs
• Composes approximately 16% of body weight

Serous membrane (serosa)
•
•
•
•
Parietal membranes—line closed body cavities
Visceral membranes—cover visceral organs
Pleura—surrounds a lung and lines the thoracic cavity
Peritoneum—covers the abdominal viscera and lines the
abdominal cavity
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Slide 35
Body Membranes
• Mucous membrane (mucosa)


Lines and protects organs that open to the exterior of the body

Found lining ducts and passageways of respiratory, digestive, other tracts

Lamina propria—fibrous connective tissue underlying mucous epithelium

Mucus is made up mostly of water and mucins—proteoglycans that form a
double-layer protection against environmental microbes (Figure 5-41)
Connective tissue membranes
• Do not contain epithelial components
• Synovial membranes—line the spaces between bone in joints
• Have smooth and slick membranes that secrete synovial fluid
• Help reduce friction between opposing surfaces in a moveable joint
• Synovial membranes also line bursae
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Slide 36
The Big Picture:
Tissues, Membranes, and the Whole Body

Tissues and membranes maintain homeostasis

Epithelial tissues
• Form membranes that contain and protect the internal
fluid environment
• Absorb nutrients
• Secrete products that regulate functions involved
in homeostasis

Connective tissues
• Hold organs and systems together
• Form structures that support the body and permit
movement
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Slide 37
The Big Picture:
Tissues, Membranes, and the Whole Body

Tissues and membranes maintain
homeostasis (cont.)

Muscle tissues
• Work with connective tissues to permit movement

Nervous tissues
• Work with glandular epithelial tissue to regulate
body function
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Slide 38