Tissue-similar cells organized into layers or groups Tissues-Chapter 5 Tissue-similar cells organized into layers or groups

Primary Tissues Epithelial tissue-covers and lines Connective tissue-all over Muscular tissue-contracts Nervous tissue-conducts impulses

Epithelial Tissue covers surfaces and lines cavities cells are tightly packed capable of reproduction lacks blood vessels connected to underlying tissues by a nonliving basement membrane cell types: squamous (flat), cuboidal, columnar simple (1 layer) and stratified ( >1 layer)

Simple Squamous Epithelium one layer of flat cells functions in diffusion, osmosis, filtration locations: air sacs of lungs, lines blood vessels

Figure 05.01

Simple Cuboidal Epithelium one layer of “cube”-shaped cells function: secretion location: lines ducts

Figure 05.02

Simple Columnar Epithelium one layer of tall cells function: absorption may have mucus-producing goblet cells associated with it may have microvilli (tiny finger-like projections on free surface) in organs requiring lots of absorption such as small intestine location: lines digestive organs (stomach, small & large intestine)

MICROVILLI

Pseudostratified Columnar Epithelium one layer of cells, but they are different heights, giving appearance of more than one layer has cilia on free surface, may have goblet cells function: move substances across free surface location: lines passageways in respiratory tract (trachea, bronchi), lines reproductive tubes

Figure 05.05

Stratified Squamous Epithelium many layers of cells with the upper layers being flattened mitosis occurs in lower layers and existing cells are pushed to the surface (becoming flattened) function: protection location: skin, esophagus, oral cavity, anus, vagina

Transitional Epithelium a few to several layers of cube-shaped cells function: distensibility location: urinary bladder

Glandular Epithelium Exocrine Glands have ducts secrete “juices” unicellular (goblet cells) or multicellular Endocrine Glands no ducts secrete “hormones” into blood

Types of Exocrine Glands Based on How They Secrete Merocrine-release secretion only into duct-- Ex: some sweat glands (odorless), pancreas, tear glands Apocrine-release secretion within pieces of cells-- Ex: some sweat glands (odor), mammary glands Holocrine-release secretion within whole cells-- Ex: oil glands of skin

Connective Tissue Cells may be widely spaced. The area between the cells is the MATRIX, which is composed of GROUND SUBSTANCE (liquid - solid) and FIBERS.

Cell Types Fibroblasts-most abundant cell type-produces fibers Macrophages-phagocytes Mast cells-produce heparin(anticoagulant) and histamine (inflam-mation) Fibers Collagenous-made of thick bundles of the protein collagen-very strong Reticular-made of thin, branching bundles of collagen-give delicate support Elastic-made of the protein elastin

Types of Connective Tissue Identified mostly by the ground substance and fibers

Loose (Areolar) C.T. has fibroblasts jelly-like ground substance with some collagenous and elastic fibers loosely arranged filler substance; holds fluids

Figure 05.18

Adipose Tissue cells are designed to store fat functions in cushioning, heat insulation, energy storage

Figure 05.19

Reticular C.T. contains reticular fibers function is internal support location: spleen, lymph nodes, liver

Figure 05.20 Reticular Fibers

Dense Regular Fibrous C.T. has lots of collagenous fibers which are parallel to each other function: VERY strong location: tendons, ligaments, sclera Lacks blood vessels….therefore, slow to heal

Figure 05.21

Dense Irregular Fibrous C.T. has lots of collagenous fibers that run in all directions location: dermis of skin

Elastic C.T. has collagenous and ELASTIC fibers function: elasticity location: walls of arteries, vocal cords

Figure 05.22

Cartilage has a solid gel-like ground substance with fibers embedded in it cells (chondrocytes) reside in cavities called lacunae slow to heal because it lacks a blood supply --- receives nourishment from blood vessels in the outer covering called the perichondrium 3 types: hyaline cartilage, elastic cartilage, and fibrocartilage

Hyaline Cartilage most common cartilage looks like white glass location: ends of bones, nose, in walls of trachea and bronchi associated with bone growth and development

Figure 05.23

Elastic Cartilage has elastic fibers location: larynx, ears

Figure 05.24

Fibrocartilage has lots of parallel collagenous fibers---very strong location: intervertebral disks, in knee joint

Figure 05.25

Bone (Osseous) Tissue has a solid ground substance made of mineral (calcium, phosphorus) salts--also has collagenous fibers cells (osteocytes) are in cavities (lacunae) matrix is arranged in layers (lamellae) around channels (Haversian/central canals) which contain blood vessels and nerve fibers tiny canals (canaliculi) connect lacunae

Central/Haversian Canal

Blood liquid ground substance contains red blood cells, white blood cells, and platelets

Reticuloendothelial tissue made of all the body’s phagocytes (ex: macrophages) widespread--cells may be resident or wandering

Membranes Serous membranes -line cavities without external openings-produce thin, watery serous fluid-ex: visceral and parietal pleura Mucous membranes -line body cavities with external openings-produce thick, sticky mucus-ex: lining of digestive, urinary, repro, and respiratory tracts Synovial membranes -line joint cavities-produce thick, clear synovial fluid Cutaneous membrane-skin