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2. Bell Ringer
2.01 What is tissue? 2.02 What are some of the different types of tissue found within the human body? 2.03 Why do we need different types of tissue?
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3. I. Tissue: The Living Fabric
A. Individual body cells are specialized and perform specific functions
B. Tissues
Groups of cells similar in structure & function
Four basic tissue types
Epithelial
Connective
Muscle
Nervous
C. Histology
1. Study of tissues
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4. Nervous tissue: Internal communication • Brain • Spinal cord • Nerves
Figure 4.1 Overview of four basic tissue types: epithelial, connective, muscle, and nervous tissues.
Nervous tissue: Internal communication
• Brain
• Spinal cord
• Nerves
Muscle tissue: Contracts to cause movement
• Muscles attached to bones (skeletal)
• Muscles of heart (cardiac)
• Muscles of walls of hollow organs (smooth)
Epithelial tissue: Forms boundaries between different
environments, protects, secretes, absorbs, filters
• Lining of digestive tract organs and other hollow organs
• Skin surface (epidermis)
Connective tissue: Supports, protects, binds
other tissues together
• Bones
• Tendons
• Fat and other soft padding tissue
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5. II. Epithelial Tissue
Epithelial tissue (epithelium) is asheet of cells that covers body surfaces or cavities
1. Two main forms:
a. Covering and lining epithelia
i. On external and internal surfaces
ii. Ex. skin
b. Glandular epithelia
i. Secretory tissue in glands
ii. Ex. salivary glands
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6. 3. Main Functions a. Protection b. Absorption c. Filtration d
3. Main Functions a. Protection b. Absorption c. Filtration d. Excretion e. Secretion f. Sensory Reception
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7. B. Special Characteristics of Epithelial Tissues
Epithelial tissue has 5 characteristics
Polarity
Cells have a top and bottom
Apical Surface (top)
Basal Surface (bottom)
b. Specialized contacts
Tissues fit closely together
Many form continuous sheets
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8. c. Supported by connective tissues
i. helps reinforce and resist stretching and tearing
d. Avascular, but innervated
No blood vessels are found in epithelial tissue
Nourishment must come from other tissues
ii. Epithelia DO have nerve fibers
e. Regeneration
i. Epithelial cells have high regenerative capacities
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9. C. Classification of Epithelia
1. All epithelial tissues have two names
a. First name indicates number of cell layers
i. Simple epithelia are a single layer thick
ii. Stratified epithelia are two or more layers thick
b. Second name indicates shape of cells
i. Squamous: flattened and scale-like
ii. Cuboidal: box-like, cube
iii. Columnar: tall, column-like
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10. c. In stratified epithelia, shape can vary in each layer, so cell is named according to the shape in the outermost layer
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11. Figure 4.2a Classification of epithelia.
Apical surface
Basal surface
Simple
Apical surface
Basal surface
Stratified
Classification based on number of
cell layers.
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12. Figure 4.2b Classification of epithelia.
Squamous
Cuboidal
Columnar
Classification based on cell shape.
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13. 2. Gland
a. One or more cells that makes and secretes an aqueous fluid called a secretion
b. Classified by:
i. Site of product release:
Endocrine: internally secreting
Exocrine: externally secreting
ii. Relative number of cells forming the gland
Unicellular
multicellular
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14. Bell Ringer
2.04 Describe what Simple Cuboidal Epithelia would look like How would you classify epithelium that is multiple layers with column shaped cells?
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15. III. Muscle Tissue
A. Characteristics 1. Highly vascularized 2. Responsible for most types of movement 3. Muscle cells possess myofilaments a. made up of actin and myosin proteins that bring about contraction B. Three types of muscle tissues: 1. Skeletal muscle 2. Cardiac muscle 3. Smooth muscle
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16. Bell Ringer
2.06 What type of gland secretes hormones? 2.07 What type of muscle tissue is voluntary?
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17. IV. Connective Tissue
A. Connective tissue is the most abundant and widely distributed of primary tissues 1. Major functions a. binding and support b. protecting c. insulating d. storing reserve fuel e. transporting substances (blood)
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18. 2. Four main classes a. Connective tissue proper b. Cartilage c. Bone
d. Blood
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19. Table 4.1-1 Comparison of Classes of Connective Tissues
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20. Table 4.1-2 Comparison of Classes of Connective Tissues (continued)
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21. B. Structural Elements of Connective Tissue
1. All connective tissues have three main elements
a. Ground substance
i. gel-like material between cells
b. Fibers
i. Collagen
Provides Strength
ii. Elastic Fibers
Allows for stretching
iii. Reticular
Provides cushioning
c. Cells
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22. 2. The first two elements together make up the extracellular matrix (ECM)
3. Composition and arrangement of these three elements vary considerable in different types of connective tissue
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23. Cell types Extracellular matrix Ground substance Fibers Macrophage
Figure 4.7 Areolar connective tissue: A prototype (model) connective tissue.
Cell types
Extracellular
matrix
Ground substance
Fibers
Macrophage
• Collagen fiber
• Elastic fiber
• Reticular fiber
Fibroblast
Lymphocyte
Fat cell
Capillary
Mast cell
Neutrophil
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24. Fibroblasts found in connective tissue proper
C. Cells
“Blast” cells
Immature form of cell that actively secretes ground substance and ECM fibers
4 Types
Fibroblasts found in connective tissue proper
Chondroblasts found in cartilage
Osteoblasts found in bone
Hematopoietic stem cells in bone marrow
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25. 2. “Cyte” Cells a. Mature, less active form of “blast” cell that now becomes part of and helps maintain health of matrix
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26. 3. Other cell types a. Fat cells i. store nutrients b
3. Other cell types a. Fat cells i. store nutrients b. White blood cells i. tissue response to injury c. Mast cells i. initiate inflammatory response d. Macrophages i. Phagocytic cells that “eat” dead cells and bacteria
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27. Bell Ringer
2.08 Name the 3 types of Loose Connective Tissue 2.09 What does ECM stand for? 2.10 What type of cells help create the ECM?
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28. V. Nervous Tissue
A. Main component of nervous system (brain, spinal cord, nerves)
1. Regulates and controls body functions
2. Made up of two types of cells:
a. Neurons
b. Neuroglia
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29. Nervous tissue Nuclei of supporting cells Cell body of a neuron Neuron
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 nonexcitable
supporting cells.
Neuron processes
Cell body
Nuclei of
supporting
cells
Axon
Dendrites
Cell body
of a neuron
Function: Neurons transmit
electrical signals from sensory
receptors and to effectors
(muscles and glands); supporting
cells support and protect neurons.
Neuron
processes
Location: Brain, spinal
cord, and nerves.
Photomicrograph: Neurons (350×)
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