Title: Chapter 4: The Tissue Level of Organization
1Chapter 4 The Tissue Level of Organization
2What are the four tissues of the body?
3- Tissues are collections of cells and cell
products that perform specific, limited functions - Histology
- 4 tissue types form all the structures of the
human body - epithelial, connective, muscle, and neural
4Epithelial Tissues
- Epithelia
- layers of cells covering internal or external
surfaces - Glands
- structures that produce secretions
5What are the special structures and functions of
epithelial tissues?
6Characteristics of Epithelia
- Cellularity
- Polarity
- Attachment (basal lamina)
- Avascularity
- Regeneration
7Functions of Epithelial Tissue
- Provide physical protection
- Control permeability
- Provide sensation
- Produce specialized secretions (glandular
epithelium) - Microvilli or cilia
8Maintaining Epithelia Integrity
- Intercellular connections
- Attachment to the basal lamina
- Epithelial maintenance and repair
9Intercellular Connections
- Support and communication
Figure 42a
10Large Connections
- CAMs (cell adhesion molecules)
- transmembrane proteins
- Intercellular cement
- glycoproteins
- Hyaluronan (hyaluronic acid)
11Cell Junctions
- Form bonds with other cells or extracellular
material - tight junctions
- gap junctions
- desmosomes
12Tight Junctions
- Interlocking membrane proteins
- Prevents passage of water and
solutes
Figure 42b
13Gap Junctions
- Allow rapid communications
- Held together by channel proteins (connexons)
- Allow ions to pass
Figure 42c
14Desmosomes
- CAMs and intercellular cement
- Allow bending and twisting without separation
Figure 42d
15Attachment to Basal Lamina
- Epithelial cells hold onto each other and are
connected to the rest of the body - Inner surface is connected to a 2-part basal
lamina - Lamina lucidia
- Lamina densa
16Maintenance Repair
- An epithelium must continuously repair and renew
itself - Function of stem cells (germinative cells)
located near basement membrane
17Classes of Epithelia
- Based on shape and layers
Table 41
18Layers
- Simple epithelium
- single layer of cells
- Stratified epithelium
- several layers of cells
- Pseudo-stratified epithelium
- single layer of cells that appears stratified
19Cell Shape
- Squamous epithelia
- flat shaped
- Cuboidal epithelia
- square shaped
- Columnar epithelia
- tall shaped
20Glandular Epithelia
- Endocrine
- Release hormones
- into interstitial fluid
- no ducts
- Exocrine
- Produce secretions
- onto epithelial surfaces
- through ducts
Figure 46
21- Exocrine glands can be classified by
- Mode of secretion
- Type of secretion
- Structure of gland
- Unicellular or multi-cellular
- Simple vs. compound
22Modes of Secretion
Figure 46a
23Modes of Secretion
Figure 46b
24Modes of Secretion
Figure 46c
25Types of Secretions
26What are the structures and functions of
different types of connective tissues?
27Structure of Connective Tissues
- Specialized cells
- Matrix
- Solid extracellular protein fibers
- Fluid extracellular ground substance
28Functions of Connective Tissues
- Connect epithelium to the rest of the body (basal
lamina) - Provide structure (bone)
- Transport materials (blood)
- Protection
- Store energy (fat)
- Defense
29Classification of Connective Tissues
- Connective tissue proper
- connect and protect
- Fluid connective tissues
- transport
- Supportive connective tissues
- structural strength
30Connective Tissue Proper
Figure 48
318 Cell Types of Connective Tissue Proper
- Fibroblasts
- Macrophages
- Adipocytes
- Mesenchymal cells
- Melanocytes
- Mast cells
- Lymphocytes
- Microphages
32Fibers in Connective Tissue Proper
- Collagen fibers
- most common strong and flexible
- tendons and ligaments
- Elastic fibers
- contain elastin
- Reticular fibers
- strong and flexible
- resists force in many directions
33Ground Substance
- In connective tissue proper and ground substance
- is clear, colorless, and viscous
- fills spaces between cells and slows pathogens
34Categories of Connective Tissue Proper
- Loose connective tissue
- more ground substance, less fibers
- Areolar adipose reticular
- Dense connective tissue
- more fibers, less ground substance
- e.g., tendons
35Dense Connective Tissues
- Connective tissues proper, tightly packed with
high numbers of collagen or elastic fibers - dense regular connective tissue
- dense irregular connective tissue
36Fluid Connective Tissues
- Fluid connective tissues
- blood and lymph
- watery matrix of dissolved proteins
- carry specific cell types (formed elements)
37Formed Elements of Blood
Figure 412
38Supportive Connective Tissues
- Support soft tissues and body weight
- cartilage
- for shock absorption and protection
- Chondrocytes
- Hyaline cartilage Elastic cartilage
Fibrocartilage - Bone (osseous tissue)
- calcified (made rigid by calcium salts, minerals)
- for weight support
- Osteocytes
39- How do epithelial and
- connective tissues combine to
- form 4 types of membranes?
40Membranes
- Membranes
- are physical barriers
- that line or cover portions of the body
- Consist of
- an epithelium
- supported by connective tissues
414 Types of Membranes
- Mucous- line passageways that have external
connections - Serous - Line cavities not open to the outside
- Pleural Peritoneum Pericardium
- Cutaneous - skin
- Synovial - joint cavities
Figure 416
42What are the structures and functions of the
three types of muscle tissue?
43Muscle Tissue
- Produces all body movement
- Specialized for contraction
- Actin and myosin fibers
- Muscle fibers and satellite cells
443 Types of Muscle Tissue
- Skeletal muscle
- Striated, voluntary, and multinucleated
- Cardiac muscle
- Striated, involuntary, and single nucleus
- Smooth muscle
- Nonstriated, involuntary, and single nucleus
45What is the basic structure and role of neural
tissue?
46Neural Tissue
- Also called nervous or nerve tissue
- specialized for conducting electrical impulses
- rapidly senses internal or external environment
- process information and controls responses
47Central Nervous System
- Neural tissue is concentrated in the central
nervous system - brain
- spinal cord
482 Kinds of Neural Cells
- Neurons
- nerve cells
- perform electrical communication
- Neuroglia
- support cells
- repair and supply nutrients to neurons
49The Neuron
Figure 419
50SUMMARY
- Organization of specialized cells into tissues
- epithelial tissue
- connective tissue
- muscular tissue
- nervous tissue
51- Division of epithelial tissues into epithelia and
glands - epithelia as avascular barriers for protection
- glands as secretory structures
52- Attachments of epithelia to other cells and
underlying tissues - polarity (apical surface and basal lamina)
- cell adhesion molecules (CAMs)
- cell junctions (tight junctions, gap junctions
and desmosomes)
53- Classification of epithelial cells
- by number of cell layers (simple or stratified)
- by shape of cells (squamous, columnar or cuboidal)
54- Classification of epithelial glands
- by method of secretion (exocrine or endocrine)
- by type of secretions (merocrine, apocrine,
holocrine)
55- The functions of connective tissues
- structure
- transport
- protection
- support
- connections
- energy storage
56- The structure of connective tissues
- matrix
- ground substance
- protein fibers
57- The classification of connective tissues
- connective tissue proper (cell types, fiber
types, and embryonic connective tissues) - fluid connective tissues (blood and lymph, fluid
transport systems) - supporting connective tissues (cartilage and bone)
58- The 4 types of membranes that cover and protect
organs - mucous membranes (lamina propria)
- serous membranes (transudate)
- cutaneous membrane (skin)
- synovial membrane (encapsulating joints)
59- The 3 types of muscle tissues (skeletal, cardiac,
and smooth) - The classification of muscle tissues by
striation, nucleation, and voluntary control
60- The 2 types of cells in neural tissue
- neurons and neuroglia
- The parts of a neuron (nerve cell)
- cell body, dendrites, and axon (nerve fiber)