Tissues
1
Tissues and tissue types
 Tissues are:
Group of cells similar in structure an function
Tissues are organized into organs
Histology = study of tissues
 The four tissue types are:
Epithelial
Connective
Muscular
Nervous
2
Functions of epithelium
 Physical protection
 Secretion
 Sensory perception
 Absorption
 Filtration
 Excretion
3
Epithelial tissue
 Includes glands and epithelium
Glands are secretory
 Avascular
 Polarity
 Regeneration
 Cellularity
 Supported by connective tissue
Attached to a basement membrane
4
5
Specializations of epithelium
Ciliated
Microvilli
Stereocilia
Flagella
6
Classification of epithelia
 Number of cell layers
Simple
Stratified
 Shape of apical surface cells
Squamous
Cuboidal
Columnar
7
8
9
10
Cuboidal Epithelia
11
12
Cuboidal Epithelia
13
Figure 4.4b
Transitional Epithelium
14
Figure 4.4c
15
Columnar Epithelia
16
Figure 4.5a
17
Columnar Epithelia
18
Figure 4.5b
19
Columnar Epithelia
20
Figure 4.5c
Glandular epithelia
 Epithelium that secrete substances
 Exocrine glands
Secrete through ducts onto the surface of the
gland
 Endocrine glands
Release hormones into surrounding fluid.
Ductless glands.
21
22
Part 2
23
Connective Tissues
24
Connective tissue functions and
classification:
 Protects
 Supports
 Bind tissues together
 Classification:
 Embryonic
Mesenchyme
Loose connective tissue, mucous
 Adult
25
A Classification of Adult
Connective Tissues
26
Connective tissues characteristics
 No free surface
 Vascular
Scanty in tendons
Except cartilage
 Supports the body
 Maintain body form
27
Components of the connective tissue
1)Extracellular matrix
Ground substance
Amorphous
Binds cells to fibers
Colorless
Homogeneous
Liquid, semisolid, gel-like, or hard
28
Matrix
 Fibers
Collagen (white)
Most abundant
Brings flexibility and strength to the tissue
Thicker one
Elastic (yellow)
Brings elasticity to the tissues
Can stretch and recoil
29
Fibers
 Reticular
Thinnest one
Found in smooth muscle and framework of the
organs
Brings flexibility to organs that need changes
in volume
30
31
32
Components of the connective tissue
2) Cells
Fibroblast
most abundant
Synthesis of fibers and ground substance
Macrophage
Phagocytic capacity
33
Components of the connective tissue
Adipocytes
Closely packed
Signet ring cell
Nucleus eccentric and flat
Mesenchymal cells
Mast cells
Releases histamin
Responsible for allergic reactions
Lymphocytes, etc
34
The Cells and Fibers of
Connective Tissue Proper
35
Connective tissue proper
 Classified as loose or dense
 Loose
 Areolar tissue
 Adipose tissue
 Reticular tissue
 Rich blood supply
36
Connective tissue proper
 Dense
Dense regular
Dense irregular
Elastic
Poor blood supply
37
Connective Tissue in Embryos
38
39
40
41
42
Dense Connective Tissues
43
Figure 4.12a
Dense Connective Tissues
44
Figure 4.12b
Dense Connective Tissues
45
Figure 4.12c
46
47
48
Bone, or osseous tissue
 Has osteocytes and osteoblasts
 Lacuna
 Little ground substance
 Dense mineralized matrix
 Richly Vascularized
49
Bone
50
Part 3
51
Supporting connective tissues:
Cartilage
Cells called chondrocytes or
chondroblasts
Cells found in lacunae
Firm matrix
Avascular
Three types: hyaline, elastic,
fibrocartilage
52
Types of Cartilage
53
54
Types of Cartilage
55
56
Types of Cartilage
57
58
Fluid connective tissues
• Blood
– Red blood cells, white blood cells and
platelets
– Plasma is the fluid matrix
59
Formed Elements of the Blood
60
61
Muscle tissue
Specialized for contraction
Three types
Skeletal
Cardiac
Smooth
62
Skeletal muscle
Cells are multinucleate, long, cylindrical
Presence of striation
 Voluntary muscle
63
Muscle Tissue - Skeletal
64
65
Cardiac muscle
 Cells:
Long,
1 or 2 nucleus
Branching cells
 Intercalated discs
 Presence of striation
 Involuntary muscle
66
Muscle Tissue - Cardiac
67
68
Smooth muscle tissue
 Cells
Fusiform
One central nucleus
 Non-striated
 Involuntary muscle
 Forms the wall of hollow organs
69
Muscle Tissue - Smooth
70
71