1. Chapter 6 Tissues

2. Principal Types of Tissue
Four types of tissues:
I. Epithelial tissue
II. Connective tissue
III. Muscle tissue
IV. Nervous tissue

3. Extracellular Matrix (ECM)
Functions
Helps bind tissues together structurally
Allows local communication among ECM and various cells—through connection via integrins in plasma membranes

4. Extracellular Matrix (ECM)
Components
Water
Proteins
Structural proteins
Collagen—strong, flexible protein fiber
Elastin—elastic fibers
Includes glycoproteins—proteins with a few carbohydrate attachments
Glycoprotein attachments also allow local communication within a tissue

5. I. Epithelial Tissue Functions Protection Sensory functions Secretion
Absorption
Excretion

6. I. Epithelial Tissue Types and locations
Epithelium is divided into two types:
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

7. I. Epithelial Tissue Classification of epithelial tissue
Classification based on cell shape
Squamous
Cuboidal
Columnar
Pseudostratified columnar

8. I. Simple epithelium 1. Simple squamous epithelium
One-cell layer of flat cells
Permeable to many substances
Examples: endothelium—lines blood vessels; mesothelium—pleura

9. I. Simple epithelium 2. Simple cuboidal epithelium
One-cell layer of cuboidal cells
Found in many glands and ducts

10. I. Simple epithelium 3. Simple columnar epithelium
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

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12. I. Simple epithelium 4. Pseudostratified columnar epithelium
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

13. I. Stratified epithelium5.
A. Stratified squamous (keratinized) epithelium
Multiple layers of flat, squamous cells
Cells filled with keratin
Covers outer skin on body surface

14. I. Stratified epithelium5.
B. Stratified squamous (nonkeratinized) epithelium
Lines vagina, mouth, and esophagus
Free surface is moist
Primary function is protection

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17. I. Stratified epithelium
6. Stratified cuboidal epithelium
Two or more rows of cells are typical
Basement membrane is indistinct
Located in sweat gland ducts and pharynx

18. I. Stratified epithelium
7. 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

19. I. Stratified epithelium
8. Stratified transitional epithelium
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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21. Can you identify these? B A E C D F G

22. II. 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

23. II. Connective Tissue Four main types: 1.Fibrous 2. Bone 3. Cartilage
A. Loose, ordinary (areolar)
B. Adipose
C. Reticular
D. Dense
Irregular
Regular (collagenous and elastic)
2. Bone
A. Compact bone
B. Cancellous bone
3. Cartilage
A. Hyaline
B. Fibrocartilage
C. Elastic
4. Blood

24. 1. Fibrous connective tissue
A. Loose, ordinary (areolar) connective tissue
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
Function—stretchy, flexible connection

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26. 1. Fibrous connective tissue
B. Adipose tissue
Similar to loose connective tissue but contains mainly fat cells
Functions—protection, insulation, support, and food reserve

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29. 1. Fibrous connective tissue
C. Reticular tissue
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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31. 1. Fibrous connective tissue D. 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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34. 2. Bone tissue Highly specialized connective tissue type Functions:
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

35. A. Compact bone Osteon (Haversian system) Cell types:
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)
In membranes—e.g., flat bones of skull
From cartilage (endochondral)—e.g., long bones, such as the humerus

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39. B. Cancellous bone 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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42. 3. 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

43. 3. Types of Cartilage A. Hyaline B. Fibrocartilage C. Elastic
Appearance is shiny and translucent
Most prevalent type of cartilage
Located on the ends of articulating bones
B. Fibrocartilage
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)
C. Elastic
Contains many fine, elastic fibers
Provides strength and flexibility
Located in external ear and larynx

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47. 4. Blood A liquid tissue 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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49. 4. 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

50. III. Muscle Tissue Types (Table 5-7)
1. Skeletal, or striated voluntary (Figure 5-32)
2. Smooth, or nonstriated involuntary, or visceral (Figures 5-33 and 5-34)
3.Cardiac, or striated involuntary (Figure 5-35)

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57. III. Muscle Tissue Microscopic characteristics
1. Skeletal muscle—threadlike cells with many cross striations and many nuclei per cell
2. Smooth muscle—elongated, narrow cells, no cross striations, one nucleus per cell
3. Cardiac muscle—branching cells with intercalated disks (formed by abutment of plasma membranes of two cells)

58. IV. Nervous Tissue
Functions—rapid regulation and integration of body activities
Specialized characteristics
Excitability
Conductivity
Organs
Brain
Spinal cord
Nerves

59. IV. Nervous Tissue Cell types Neuron—conducting unit of system
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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61. IV. Tissue Repair
Tissues have a varying capacity to repair themselves; damaged tissue regenerates or is replaced by scar tissue
Regeneration—growth of new tissue
Scar—dense fibrous mass; unusually thick scar is a keloid
Epithelial and connective tissues have the greatest ability to regenerate
Muscle and nervous tissues have a limited capacity to regenerate

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64. Body Membranes
Thin tissue layers that cover surfaces, line cavities, and divide spaces or organs (Figure 6-39, Table 6-8)
Epithelial membranes are most common type (Figure 6-40)
Cutaneous membrane (skin)
Primary organ of integumentary system
One of the most important organs
Composes approximately 16% of body weight 64

65. Body Membranes Epithelial membranes (cont) 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 65

66. Body Membranes Epithelial membranes (cont) Mucous membrane (mucosa)
Lines and protects organs that open to the exterior of the body
Found lining ducts and passageways of the respiratory, digestive, and 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 of protection against environmental microbes (Figure 6-41) 66

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68. 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 68

69. 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 69

70. 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 tissues to regulate body function 70