1. 4
Tissues

2. I. Tissues
A. Cells work together in functionally related groups called tissues
B. Tissue - A group of closely associated cells that perform related functions and are similar in structure

3. II. Four Basic Tissue Types and Basic Functions
► Epithelial tissues - covering
► Connective tissues - support
► Muscle tissues - movement
► Nervous tissue - control

4. III. Epithelial Tissue
A. Covers all body surfaces and lines all body cavities
B. Functions of epithelia
1. protection
2. secretion
3. absorption
4. diffusion
5. filtration
6. sensory reception

5. C. Special Characteristics of Epithelia
1. cellularity - cells separated by minimal extracellular material
2. specialized contacts - cells joined by special junctions
3. polarity - cell regions of the apical surface differ from the basal surface
4. avascular (no blood vessels) - epithelia receive nutrients from underlying connective tissue
5. regeneration - lost cells are quickly replaced by cell division

6. Cilia
Narrow extracellular space
Microvilli
Apical region of an epithelial cell
Cell junctions
Tight junction
Epithelium
Adhesive belt
Desmosome
Gap junction
Basal region
Basal lamina
Basement membrane
Reticular fibers
Nerve ending
Connective tissue
Capillary

7. ► First name of tissue indicates number of cell layers Simple epithelia - single layer of cells attached to basement membrane Stratified epithelia - multiple layers of cells (basal cells attached to basement membrane) ► Last name of tissue describes shape of cells Squamous—cells are wider than tall (plate-like) Cuboidal—cells are as wide as tall, like cubes Columnar—cells are taller than they are wide, like columns

8. Classification based on number of cell layers
Apical surface
Basal surface
Simple
Apical surface
Basal surface
Stratified
Classification based on number of cell layers 8

9. Classification based on cell shape
Squamous
Cuboidal
Columnar
Classification based on cell shape 9

10. Simple Squamous Epithelium
Description
A. single layer; flat cells with disc-shaped nuclei
Functions
A. passage of materials by passive diffusion and filtration
B. secretes lubricating substances in serosae
Location
A. alveoli of lungs
B. renal corpuscles
C. lining of heart, blood, and lymphatic vessels
D. lining of ventral body cavity (serosae)

11. Simple squamous epithelium
Description: Single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia.
Air sacs of lung tissue
Nuclei of squamous epithelial cells
Function: Allows passage of materials by diffusion and filtration in sites where protection is not important; produces lubricating fluid in serosae.
Location: Kidney glomeruli; air sacs of lungs; lining of heart, blood vessels, and lymphatic vessels; lining of ventral body cavity (serosae).
Photomicrograph: Simple squamous epithelium forming part of the alveolar (air sac) walls (140). 11

12. Simple squamous epithelium12

13. Simple Cuboidal Epithelium
Description
A. single layer of cube-like cells; large, spherical central nuclei
Function
A. secretion and absorption
Location
A. kidney tubules, small glands, ovary surface

14. Simple cuboidal epithelium
Description: Single layer of cubelike cells with large, spherical central nuclei.
Simple cuboidal epithelial cells
Function: Secretion and absorption.
Basement membrane
Location: Kidney tubules; ducts and secretory portions of small glands; ovary surface.
Connective tissue
Photomicrograph: Simple cuboidal epithelium in kidney tubules (430). 14

15. 15

16. Simple Columnar Epithelium
Description—single layer of column-shaped (rectangular) cells
A. some bear cilia at their apical surface
B. may contain goblet cells
Function
A. absorption; secretion of mucus, enzymes, and other substances
B. ciliated type propels mucus or reproductive cells by ciliary action
Location
A. nonciliated- stomach, intestines, gall bladder
B. ciliated – bronchi, uterine tubes, uterus

17. Simple columnar epithelium
Description: Single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells).
Microvilli
Goblet cell
Simple columnar epithelial cell
Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action.
Location: Nonciliated type lines most of the digestive tract (stomach to anal canal), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus.
Basement membrane
Photomicrograph: Simple columnar epithelium of the small intestine (650). 17

18. 18

19. Pseudostratified Columnar Epithelium Description
A.like simple columnar, but uneven surface
B. may contain goblet cells and bear cilia
C. nuclei lie at varying heights within cells
D. gives false impression of stratification
Function—secretion of mucus; propulsion of mucus by cilia
Locations
A. non-ciliated type
i. ducts of male reproductive tubes
ii. ducts of large glands
B. ciliated type
i. lines trachea and most of upper respiratory tract

20. Pseudostratified columnar epithelium
Description: Single layer of cells of different heights, some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting goblet cells and bear cilia.
Cilia
Goblet cell
Pseudo- stratified epithelial layer
Function: Secretion, particularly of mucus; propulsion of mucus by ciliary action.
Location: Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract.
Basement membrane
Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (780).
Trachea 20

21. 21

22. Stratified Squamous Epithelium
Description
A. many layers of cells are squamous in shape
B. deeper layers of cells appear cuboidal or columnar
C. thickest epithelial tissue
D. adapted for protection from abrasion
1. Keratinized
a. Location—epidermis of the skin
b. contains the protective protein keratin
c. waterproof
d. surface cells are dead and full of keratin
2. Non-keratinized
a. Forms moist lining of body openings

23. Function - protects underlying tissues in areas subject to abrasio
Locations
Keratinized - forms epidermis
Non-keratinized - forms lining of mucous membranes
i. esophagus
ii. mouth
iii. anus
iv. vagina
v. urethra

24. Stratified squamous epithelium
Description: Thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers.
Stratified squamous epithelium
Function: Protects underlying tissues in areas subjected to abrasion.
Nuclei
Basement membrane
Location: Nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane.
Connective tissue
Photomicrograph: Stratified squamous epithelium lining the esophagus (280). 24

25. 25

26. Stratified Cuboidal Epithelium (rare)
Description - generally two layers of cube-shaped cells
Function - protection
Location
Forms ducts of:
1. mammary glands
2. salivary glands
3. largest sweat glands

27. Stratified cuboidal epithelium
Description: Generally two layers of cubelike cells.
Basement membrane
Cuboidal epithelial cells
Function: Protection.
Location: Largest ducts of sweat glands, mammary glands, and salivary glands.
Duct lumen
Photomicrograph: Stratified cuboidal epithelium forming a salivary gland duct (290). 27

28. 28

29. Stratified Columnar Epithelium (rare) Description A. several layers
Description
A. several layers
B. basal cells usually cuboidal superficial cells elongated
Function - protection and secretion
Location
A. rare tissue type
B. found in male urethra and large ducts of some glands

30. Stratified columnar epithelium
Description: Several cell layers; basal cells usually cuboidal; superficial cells elongated and columnar.
Stratified columnar epithelium
Basement membrane
Function: Protection; secretion.
Underlying connective tissue
Location: Rare in the body; small amounts in male urethra and in large ducts of some glands.
Photomicrograph: Stratified columnar epithelium lining the male urethra (360).
Urethra 30

31. 31

32. Transitional Epithelium
Description
A. characteristics of stratified cuboidal and stratified squamous
B. superficial cells dome-shaped when bladder is relaxed
C. squamous when full
Function
A. permits distension of urinary organs when filled with urine
Location - epithelium of urinary bladder and ureters

33. Transitional epithelium
Description: Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamous-like, depending on degree of organ stretch.
Transitional epithelium
Function: Stretches readily and permits distension of urinary organ by contained urine.
Basement membrane
Location: Lines the ureters, bladder, and part of the urethra.
Connective tissue
Photomicrograph: Transitional epithelium lining the bladder, relaxed state (365); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and become elongated when the bladder is filled with urine. 33

34. 34

35. V. Glands A. Endocrine glands (INTO the blood) ductless glands
secrete directly into surrounding tissue fluid
produce messenger molecules called hormones
B. Exocrine glands (ONTO a surface)
1. ducts carry substances to epithelial surface
a. mucus-secreting glands
b. sweat and oil glands
c. salivary glands
d. liver and pancreas

36. C. Unicellular Exocrine Glands (The Goblet Cell)
1. goblet cells produce mucin
2. mucin  water  mucus
3. protects and lubricates many internal body surfaces
4. goblet cells are a unicellular exocrine gland (e.g. intestine)

37. D. Multicellular Exocrine Glands
1. have two basic parts
2. epithelium-walled duct
3. classified by structure of duct
a. simple
b. compound
c. tubular
d. alveolar
e. tubuloalveolar

38. Compound duct structure
Simple duct structure
Compound duct structure
(duct does not branch)
(duct branches)
Tubular secretory structure
Simple tubular
Simple branched tubular
Compound tubular
Example Intestinal glands
Example Stomach (gastric) glands
Example Duodenal glands of small intestine
Alveolar secretory structure
Simple alveolar
Simple branched alveolar
Compound alveolar
Compound tubuloalveolar
Example No important example in humans
Example Sebaceous (oil) glands
Example Mammary glands
Example Salivary glands
Surface epithelium
Duct
Secretory epithelium 38

39. 1. factors binding epithelial cells together
E. Cell Junctions
1. factors binding epithelial cells together
2. adhesion proteins link plasma membranes of adjacent cells
F. Special cell junctions
1. tight junctions - close off intercellular space
a. found at apical region of most epithelial tissues types
b. some proteins in plasma membrane of adjacent cells are fused
c. prevent molecules from passing between cells
2. adhesive belt junctions - anchoring junction
3. transmembrane linker proteins
a. attach to cytoskeleton and bind adjacent cells

40. 4. desmosomes—main junctions for binding cells together
a. scattered along abutting sides of adjacent cells
b. intermediate filaments extend across the cytoplasm
c. and anchor at desmosomes on opposite side of the cell
d. are common in cardiac muscle and epithelial tissue
5. gap junctions - passageway between two adjacent cells
a. let small molecules move directly between cells
b. cells are connected by hollow protein channel
c. passage of small atoms (e.g. ions) or molecules
d. function in intercellular communication

41. 41 Plasma membranes of adjacent cells Microvilli Intercellular space
Basement membrane
Intercellular space
Intercellular space
Plaque
Channel between cells (connexon)
Interlocking junctional proteins
Intercellular space
Intermediate filament (keratin)
Linker glycoproteins (cadherins)
Tight junctions: Impermeable junctions prevent molecules from passing through the intercellular space.
Desmosomes: Anchoring junctions bind adjacent cells together and help form an internal tension-reducing network of fibers.
Gap junctions: Communicating junctions allow ions and small molecules to pass from one cell to the next for intercellular communication. 41

42. G. The Basal Lamina
1. at boundary between the epithelium and connective tissue
2. non-cellular supporting sheet between the epithelial tissue
3. connective tissue deep to it
4. consists of proteins secreted by epithelial cells
5. Functions
a. determining which molecules from capillaries enter the epithelium
b. scaffolding along which regenerating epithelial tissue cells can migrate
c. underlying connective tissue deep to it form
the basement membrane

43. VI. Epithelial Surface Features
A. Microvilli—fingerlike extensions of plasma membrane
1. have a core of actin filaments that stiffen the microvillus
2. abundant in kidney tubules and small intestine
3. surface across which small molecules enter or leave cells

44. Microvilli
Microvillus
Actin filaments 44

45. B. Cilia – whiplike extensions of apical surface membranes
1. microtubules held together by cross-linking proteins
2. microtubules arranged in pairs called doublets
3. movement is generated when adjacent doublets grip each
other with the motor protein dynein
4. cilia originate as microtubules assemble around centrioles

46. Cilia
Layer of mucus
Cell surface 46

47. VII. Connective Tissue A. Most diverse and abundant tissue
A. Most diverse and abundant tissue
B. Main classes of connective tissue
1. connective tissue proper
2. cartilage
3. bone tissue
4. blood

48. C. Important functions of connective tissue type
1. form basis of the skeleton
2. store and carry nutrients
3.surround blood vessels and nerves
4. support and binding of other tissues
5. holding body fluids (interstitial fluid  lymph)
6. defending body against infection
7. storing nutrients as fat and protection

49. D. Special Characteristics of Connective Tissue
1. few cells, abundant extracellular matrix
2. extracellular matrix is composed of ground substance
3. extracellular fibers
4. extracellular matrix produced by cells called fibroblasts
5. common embryonic origin is mesenchyme

50. E. Structural Elements of Connective Tissue
1. connective tissues differ in structural properties
2. differences in types of cells
3. differences in composition of extracellular matrix
4. however, connective tissues all share structural elements

51. F. Cells
1. fibroblasts - primary cell type of connective tissues produces the extracellular matrix
2. chondroblasts secrete matrix in cartilage (chondro)
3. osteoblasts secrete matrix in bone (osteo)

52. G. Fibers
1. Extracellular matrix is composed of fibers and ground substance
2. Fibers function in support and also have unique properties
a. collagen fibers - strongest; resist tension
b. reticular fibers - bundles of special type of cartilage
c. elastic fibers - contain elastin

53. H. Ground substance
1. Is produced by primary cell type of the tissue
2. Is usually gel-like substance consisting of:
a. proteoglycans and glycosaminoglycans (arthritis)
b. cushions and protects body structures
c. holds tissue fluid

54. Connective Tissue Extracellular matrix Ground substance Macrophage
Fibers
Collagen fiber
Elastic fiber
Reticular fiber
Fibroblast
Lymphocyte
Fat cell
Capillary
Mast cell
Neutrophil 54

55. VIII. Embryonic Connective Tissue (Mesenchyme)
A. has gel-like ground substance
B. cells are star-shaped mesenchymal cells
C. connective tissues arise from mesenchyme in the embryo

56. Embryonic connective tissue: mesenchyme
Description: Embryonic connective tissue; gel-like ground substance containing fibers; star-shaped mesenchymal cells.
Mesenchymal cells
Ground substance
Function: Gives rise to all other connective tissue types.
Fibers
Location: Primarily in embryo.
Photomicrograph: Mesenchyme, an embryonic connective tissue (385). The matrix is composed of the fluid ground substance (clear-appearing background) and fine, sparse fibers. 56

57. 57

58. IX. Areolar (Loose) Connective Tissue
A. underlies all epithelial tissues
B. between muscle and skin
C. surrounds small nerves and blood vessels
D. structures & functions shared by other connective tissues
E. fibers provide support
F. Three types of protein fibers in extracellular matrix
a. collagen fibers
b. reticular fibers
c. elastic fibers
► Fibroblasts produce these fibers

59. G. Tissue fluid (interstitial fluid)
1. watery fluid in extracellular matrix (comes from blood plasma)
K. Ground substance
1. made and secreted by fibroblasts
2. viscous, spongy part of extracellular matrix
a. Consists of sugar and protein molecules
Main battlefield in fight against infection
i. macrophages
ii. plasma cells
iii. mast cells
iv. white blood cells
v. neutrophils

60. Description
1. gel-like matrix with all three fiber types
2. cells of areolar connective tissue
3. fibroblasts, macrophages, mast cells, white blood cells
Function
1. wraps and cushions organs
2. holds and conveys tissue fluid (interstitial fluid)
3. Important role in inflammation
Locations
1. widely distributed under epithelia
2. ackages organs
3. surrounds capillaries

61. Connective tissue proper: loose connective tissue, areolar
Description: Gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some white blood cells.
Elastic fibers
Ground substance
Function: Wraps and cushions organs; its macrophages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid.
Fibroblast nuclei
Collagen fibers
Location: Widely distributed under epithelia of body, e.g., forms lamina propria of mucous membranes; packages organs; surrounds capillaries.
Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (340).
Epithelium
Lamina propria 61

62. 62

63. X. Adipose Tissue Description 1. closely packed adipocytes
2. have nucleus pushed to one side by fat droplet
3. highly vascularized
Function
1. provides reserve food fuel
2. insulates against heat loss
3. supports and protects organs
Location
1. under skin (hypodermis)
2. around kidneys
3. behind eyeballs, within abdomen, and in breasts

64. Connective tissue proper: loose connective tissue, adipose
Description: Matrix as in areolar connective tissue, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet.
Nucleus of fat cell
Function: Provides reserve food fuel; insulates against heat loss; supports and protects organs.
Vacuole containing fat droplet
Location: Under skin in the hypodermis; around kidneys and eyeballs; within abdomen; in breasts.
Adipose tissue
Photomicrograph: Adipose tissue from the subcutaneous layer under the skin (350).
Mammary glands 64

65. 65

66. XI. Reticular Connective Tissue
Description - network of reticular fibers in loose ground substance
Function
1. forms a soft, internal skeleton (stroma)
2. supports other cell types
Location - Lymph nodes, bone marrow, and spleen

67. Connective tissue proper: loose connective tissue, reticular
Description: Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network.
White blood cell (lymphocyte)
Function: Fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages.
Reticular fibers
Location: Lymphoid organs (lymph nodes, bone marrow, and spleen).
Photomicrograph: Dark-staining network of reticular connective tissue fibers forming the internal skeleton of the spleen (350).
Spleen 67

68. 68

69. XII. Dense Connective Tissue
A. Two types of dense connective tissue
1. Dense irregular connective tissue
2. Dense regular connective tissue
(have more collagen than areolar connective tissue)

70. B. Dense Irregular Connective Tissue
Description
1. collagen fibers are thick and irregularly arranged
2. contains some elastic fibers and fibroblasts
Function
1. withstands tension
2. provides structural strength
Location
1. dermis of skin
2. submucosa of digestive tract
3. fibrous capsules of joints
4. capsules surrounding organs
(e.g. kidneys, bones, and lymph nodes )

71. Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast; defense cells and fat cells are also present.
Nuclei of fibroblasts
Function: Able to withstand tension exerted in many directions; provides structural strength.
Collagen fibers
Location: Fibrous capsules of organs and of joints; dermis of the skin; submucosa of digestive tract.
Photomicrograph: Dense irregular connective tissue from the dermis of the skin (300).
Fibrous layer of joint capsule 71

72. 72

73. C. Dense Regular Connective Tissue
Description
a. collagen fibers are parallel to the direction of pull
b. fibroblasts are located between collagen fibers
c. contains few elastic fibers
d. has great tensile strength
e. poorly vascularized
f. forms fascia (tissue around muscles and tedons)

74. Function
a. attaches muscle to bone
b. attaches bone to bone
c. withstands great stress in one direction
Location
a. tendons and ligaments
b. aponeuroses (broad sheet-like tendons)
c. fascia around muscles

75. Connective tissue proper: dense connective tissue, dense regular
Description: Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast.
Collagen fibers
Nuclei of fibroblasts
Function: Attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction.
Location: Tendons, most ligaments, aponeuroses.
Photomicrograph: Dense regular connective tissue from a tendon (425).
Shoulder joint
Ligament
Tendon 75

76. 76

77. D. Elastic Connective Tissue
Description - Elastic fibers predominate
Function - allows recoil after stretching
Location
a. within walls of arteries
b. in certain ligaments
c. surrounding bronchial tubes

78. Connective tissue proper: dense connective tissue, elastic
Description: Dense regular connective tissue containing a high proportion of elastic fibers.
Function: Allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration.
Elastic fibers
Location: Walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes.
Photomicrograph: Elastic connective tissue in the wall of the aorta (250).
Aorta
Heart 78

79. Photomicrograph: Elastic connective tissue in the wall of the aorta (250).79

80. XIII. Cartilage all cartilages have similar structural components
all cartilages have similar structural components
1. firm, flexible tissue
2. contains no blood vessels or nerves
3. matrix contains up to 80% water
4. chondrocytes – mature cells
5. chondroblasts - immature cells for growth and maintenance
a. secrete matrix of fibers during cartilage growth

81. B. Three types of cartilage
1. Hyaline cartilage
2. Elastic cartilage
3. Fibrocartilage
► Each cartilage has specialized functions

82. C. Hyaline Cartilage Description
Description
a. imperceptible collagen fibers (hyaline = glassy)
b. are mature cartilage cells
c. lie within lacunae
Function
a. supports and reinforces
b. resilient cushion
c. resists repetitive stress
Location
a. fetal skeleton
b. ends of long bones
c. costal cartilage of ribs
d. cartilages of nose, trachea, and larynx

83. Cartilage: hyaline
Description: Amorphous but firm matrix; collagen fibers form an imperceptible network; chondroblasts produce the matrix and, when mature (chondrocytes), lie in lacunae.
Chondrocyte in lacuna
Matrix
Function: Supports and reinforces; serves as resilient cushion; resists compressive stress.
Location: Forms most of the embryonic skeleton; covers the ends of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachea, and larynx.
Photomicrograph: Hyaline cartilage from a costal cartilage of a rib (470).
Costal cartilages 83

84. 84

85. D. Elastic Cartilage
Description
a. similar to hyaline cartilage
b. more elastic fibers in matrix
Function
a. maintains shape of structure
b. allows great flexibility
Location
a. supports external ear
b. epiglottis

86. Location: Supports the external ear (pinna); epiglottis.
Cartilage: elastic
Description: Similar to hyaline cartilage, but more elastic fibers in matrix.
Chondrocyte in lacuna
Function: Maintains the shape of a structure while allowing great flexibility.
Matrix
Location: Supports the external ear (pinna); epiglottis.
Photomicrograph: Elastic cartilage from the human ear pinna; forms the flexible skeleton of the ear (510). 86

87. 87

88. a. matrix similar but less firm than hyaline cartilage
E. Fibrocartilage
Description
a. matrix similar but less firm than hyaline cartilage
b. thick collagen fibers predominate
Function - tensile strength and ability to absorb compressive shock
Location
a.intervertebral discs
b. pubic symphysis
c.discs of knee joint

89. Cartilage: fibrocartilage
Description: Matrix similar to but less firm than that in hyaline cartilage; thick collagen fibers predominate.
Function: Tensile strength with the ability to absorb compressive shock.
Collagen fibers
Location: Intervertebral discs; pubic symphysis; discs of knee joint.
Chondrocytes in lacunae
Intervertebral discs
Photomicrograph: Fibrocartilage from an intervertebral disc (175). 89

90. 90

91. XIV. Bone Tissue Description bone matrix contains:
Description
bone matrix contains:
1. inorganic Calcium salts
2. abundance of collagen fibers
3. well vascularized
► osteoblasts—secrete collagen fibers; create/maintain/remodel bone
► osteocytes—mature bone cells in lacunae
► (osteoclasts) – degrade bone during remodeling and repair

92. Function
1. supports and protects organs
2. provides levers and attachment site for muscles
3. stores calcium and other minerals
4. stores fat
5. bone marrow - site for blood cell formation
Location - Bones

93. Others: bone (osseous tissue)
Description: Hard, calcified matrix containing many collagen fibers; osteocytes lie in lacunae. Very well vascularized.
Central canal
Lacunae
Function: Supports and protects (by enclosing); provides levers for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation (hematopoiesis).
Lamella
Location: Bones.
Photomicrograph: Cross-sectional view of bone (175). 93

94. 94

95. XV. Blood Tissue Properties 1. an atypical connective tissue
2. develops from mesenchyme (embryonic tissue)
3. consists of cells surrounded by nonliving matrix
Description
1. Red blood cells, white blood cells and platelets
Function - Transport of respiratory gases, nutrients, and wastes
Location – within blood vessels and heart

96. Connective tissue: blood
Description: Red and white blood cells in a fluid matrix (plasma).
Red blood cells (erythrocytes)
White blood cells:
• Lymphocyte
• Neutrophil
Function: Transport respiratory gases, nutrients, wastes, and other substances.
Location: Contained within blood vessels.
Plasma
Photomicrograph: Smear of human blood (1650); shows two white blood cells surrounded by red blood cells. 96

97. 97

98. XVI. Covering and Lining Membranes
A. combine epithelial tissues and connective tissues
B. cover broad areas within body
C. epithelial sheet plus underlying connective tissue
D. Three Types of Membranes
1. cutaneous membrane 
2. mucous membranes 
3. serous membranes

99. 1. Cutaneous membrane
a. skin
2. Mucous membranes
a. lines hollow organs that open to surface of body
b. epithelial sheet with layer of lamina propria

100. 3. Serous membranes
a. simple squamous epithelium called mesothelium
b. produces serous fluid
c. lines closed cavities
i. visceral and parietal pleura (lungs)
ii. visceral and parietal peritoneum (intestines)
iii. visceral and parietal pericardium (heart)

101. Cutaneous membrane
Serous membranes
The cutaneous membrane (the skin) covers the body surface.
Serous membranes line body cavities that are closed to the exterior.
Cutaneous membrane (skin)
Parietal pleura
Visceral pleura
Parietal pericardium
Visceral pericardium
Mucous membranes
Mucous membranes line body cavities that are open to the exterior.
Mucosa of nasal cavity
Mucosa of mouth
Esophagus lining
Parietal peritoneum
Mucosa of lung bronchi
Visceral peritoneum
101

102. XVII. Muscle Tissue A. is a composite tissue
A. is a composite tissue
B. contains areolar connective tissue and muscle tissue
C. muscle cells also called muscle fibers
D. cells contain myofilaments
1. myofilaments contain actin and myosin
E. Three types of muscle tissue
1. skeletal muscle tissue
2. cardiac muscle tissue
3. smooth muscle tissue

103. F. Skeletal Muscle Tissue (Striated muscle; Voluntary muscle)
Description
1. long, cylindrical cells
2. multinucleate
3. obvious striations
Function - voluntary movement
Location - skeletal muscles attached to bones (occasionally to skin)

104. Part of muscle fiber (cell)
Skeletal muscle
Description: Long, cylindrical, multinucleate cells; obvious striations.
Striations
Nuclei
Function: Voluntary movement; locomotion; manipulation of the environment; facial expression.
Location: In skeletal muscles attached to bones or occasionally to skin.
Part of muscle fiber (cell)
Photomicrograph: Skeletal muscle (450). Notice the obvious banding pattern and the fact that these large cells are multinucleate.
104

105. 105

106. G. Cardiac Muscle Tissue
Description
1. branching cells, striated
2. generally uninucleate
3. cells interdigitate at intercalated discs
Function - contracts to propel blood into circulatory system
Location - occurs in walls of heart

107. Location: The walls of the heart. Nucleus
Cardiac muscle
Description: Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs).
Striations
Intercalated discs
Function: As it contracts, it propels blood into the circulation; involuntary control.
Location: The walls of the heart.
Nucleus
Photomicrograph: Cardiac muscle (355); notice the striations, branching of cells, and the intercalated discs.
107

108. Cardiac muscle
108

109. H. Smooth Muscle Tissue
Description
1. spindle-shaped cells with central nuclei
2. arranged closely to form sheets
3. no striations
Function
1. propels substances along internal passageways
2. involuntary control
Location - walls of blood vessels and GI tract

110. Location: Mostly in the walls of hollow organs.
Smooth muscle
Description: Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets.
Smooth muscle cell
Function: Propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control.
Nuclei
Location: Mostly in the walls of hollow organs.
Photomicrograph: Sheet of smooth muscle from the digestive tract (465).
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112. XVIII. Nervous Tissue Description
Description
1. main components are brain, spinal cord, and nerves
2. contains two types of cells:
a. neurons (nerve cells)- conduct nerve impulses
b. neuroglial cells (supporting cells) - supporting cells
Function - transmit electrical signals
Location - brain, spinal cord, and nerves

113. Location: Brain, spinal cord, and nerves.
Nervous tissue
Description: Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonconducting supporting cells, neuroglia (not illustrated).
Cell body of a neuron
Neuron processes
Neuron processes
Cell body
Dendrites
Axon
Function: Transmit electrical signals from sensory receptors and to effectors (muscles and glands) that control the activity of the effector organs.
Nuclei of neuroglia
Location: Brain, spinal cord, and nerves.
Photomicrograph: Neurons (125).
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