Tissues Chapter 4 Tissues groups of cells with

Tissues Chapter 4

Tissues � groups of cells with common role � 4 basic types: � Epithelial � Connective � Muscular � Nervous

Epithelial Tissue �Cells close together – continuous sheets �Cover surfaces & line cavities- always a free surface =Apical surface �Basement membrane of connective tissue �No blood vessels- avascular �Have a nerve supply � High capacity for cell division.

Categories- Table 4. 1 � Simple epithelium = ◦ 1 layer of cells � Stratified Epithelium= ◦ more than 1 layer of cells � Cell Shapes = ◦ squamous, cuboidal, columnar, transitional (change shape)

Simple Epithelium � Squamous= single layer of flat cells. � Important for filtration (kidneys) or diffusion (lungs & capillaries) � Called endothelium when lining heart, blood and lymphatic vessels � Called mesothelium when in serous membranes

Simple Squamous Epithelium single layer of flat cells

Simple Squamous Epithelium single layer of flat cells

Simple Squamous Epithelium single layer of flat cells

Simple Cuboidal Epithelium cube shaped cells, rounded nuclei

Simple Cuboidal Epithelium cube shaped cells, rounded nuclei

Simple Columnar Epithelium May be ciliated or non-ciliated

Simple Columnar Epithelium May be ciliated or non-ciliated

Simple Columnar Epithelium May be ciliated or non-ciliated

Simple Columnar Epithelium May be ciliated or non-ciliated

Pseudostratified Columnar appears stratified: nuclei at various levels

Pseudostratified Columnar appears stratified: nuclei at various levels

Stratified Squamous Epithelium � Apical layer cells are flat � Deep layers vary from cuboidal to columnar � Cells in the basal layer divide and move upward toward apical surface � Found in areas of surface wear & tear

Table 4. 1 f figure 1

Table 4. 1 f figure 2

Stratified Cuboidal Epithelium rare

Stratified Cuboidal Epithelium rare

Stratified Columnar Epithelium rare

Stratified Columnar Epithelium rare

Transitional Epithelium variable in appearance—cells can stretch

Transitional Epithelium variable in appearance—cells can stretch

Glandular Epithelium-Endocrine

Glandular Epithelium-Endocrine

Glandular Epithelium-Endocrine

Glandular Epithelium-Endocrine

Connective Tissue � Most abundant tissue type � small cells far apart � large amount of extracellular material (matrix) � Often good blood supply �Found between other tissues � Classified using matrix characteristics

Connective Tissue Cells vary with tissue type � Fibroblasts- present in several tissues ◦ secrete fibers & ground substance � Macrophages- from monocytes ◦ Engulf bacteria & cell debris by phagocytosis � Plasma cells- develop from B lymphocytes ◦ Make antibodies

Connective Tissue Cells � Mast cells- near blood cells ◦ part of reaction to injury- histamine � Adipocytes= fat cells or adipose cells ◦ Store triglycerides (fat)

Extracellular Matrix �Fluid, gel or solid plus protein fibers �Ground substance-between cells and fibers �Fibers- 3 types �Collagen fibers: very strong & flexible �Elastic fibers: smaller stretch and return to original length �Reticular fibers: provide support & strength ◦ found in basement membranes & organ support

Figure 4. 2

Loose Connective Tissue � Areolar � Adipose � Reticular

Table 4. 2 a figure 1

Table 4. 2 a figure 2

Table 4. 2 b figure 1

Table 4. 2 b figure 2

Table 4. 2 c figure 1

Table 4. 2 c figure 2

Classification � Dense Connective tissue ◦ Dense regular ◦ Dense irregular ◦ Elastic

Table 4. 2 d figure 1

Table 4. 2 d figure 2

Table 4. 2 e figure 1

Table 4. 2 e figure 2

Table 4. 2 f figure 1

Table 4. 2 f figure 2

Cartilage �Dense network of collagen & elastic fibers embedded in chondroitin sulfate �stronger than dense fibrous �Cells = chondrocytes �Occur singly or in groups �Found in spaces called lacunae �Surrounded by perichondrium �No blood vessels or nerves

Classification - Cartilage � 3 types � Hyaline- fibers not easily visible � Fibrocartilage- fibers visible � Strongest type. E. g. in vertebral discs � Elastic- chondrocytes in threadlike network e. g. ear cartilage

Table 4. 2 g figure 1

Table 4. 2 g figure 2

Table 4. 2 h figure 1

Table 4. 2 h figure 2

Table 4. 2 i figure 1

Table 4. 2 i figure 2

Bone = Osseous Tissue � More dense matrix includes Calcium & phosphorus salts � Details in Chapter 6

Liquid Connective Tissue � Blood- matrix = plasma ◦ More in chapter 14 � Lymph- matrix like blood but with less protein ◦ More in chapter 17

Muscular Tissue �large, elongated cells �contractile cells �Skeletal muscle tissue -named for location �Cardiac muscle tissue- forms wall of heart �Smooth muscle tissue –found in walls of hollow organs

Neural Tissue � Nerve cells & neuroglia � Neurons- convert stimuli into nerve impulses and conduct them � Neuroglia –do not generate nerve impulses. � Serve supportive functions

Body Membranes � 3 types of body (not cell) membranes �Mucous Membranes –line body cavities opening to exterior ◦ Secrete mucus �Serous organs Membranes- surround moving ◦ Secrete serous fluid �Synovial Membranes- line cavities of some joints. ◦ Secrete synovial fluid

Tissue Repair �New cells from stroma or parenchyma �Epithelial cells originate from stem cells in defined areas of tissue layer �Bone regenerates readily, cartilage poorly �Muscular tissue can replace cells but slowly �Nerve tissue is poorest at replacement although some stem cells seem to be available. �Replacement from stroma –> scar tissue & functional loss.

Fluorescent Microscopy Using Scanning Laser Confocal Microscopy of Skin Cells The image at the left shows a network of keratin to desmosome to keratin links. These links hold together the epithelial sheet of cells, such as in skin tissue. Notice the nuclei are stained (green) and the desmosome-keratin links are stained (red) in situ. http: //commons. wikimedia. org/wiki/ Free Use License, Accessed May 15 th 2009

Wrap Up!!! What did we learn? � 4 major categories of tissues ◦ Epithelial, connective, muscular and nervous ◦ Tissue classifications (i. e. loose connective, dense, etc. ) � Microscopy methods and magnification of obtaining tissue images � Tissue association with anatomy � Tissue Repair � These topics support many of the teaching objectives of the following TCOs: � 1, 2, 3, 4