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Berniece Leonhardt
Histology Chapter 6 Webquest Answer Key: A Guide to Tissues
Histology is the study of the microscopic structure and function of tissues. Tissues are groups of cells with similar structure and embryonic origin working together to perform a particular function in the body. There are four main types of tissues: epithelial, connective, muscle, and nervous.
This webquest will help you review the basic characteristics and functions of each tissue type, as well as some examples of where they are found in the body. You will also learn how to identify different types of tissues based on their appearance and arrangement. To complete this webquest, you will need to visit the following websites and answer the questions below.
Questions
- What are the four main functions of epithelial tissue?
- What are the two ways to classify epithelial tissue based on cell shape and arrangement?
- What are the three types of fibers found in connective tissue?
- What are the three types of muscle tissue and where are they located?
- What are the two main types of cells in nervous tissue and what are their roles?
Answers
- The four main functions of epithelial tissue are protection, absorption, filtration, and secretion.
- The two ways to classify epithelial tissue based on cell shape and arrangement are squamous (flat), cuboidal (cube-shaped), or columnar (tall and narrow) for cell shape, and simple (one layer) or stratified (multiple layers) for cell arrangement.
- The three types of fibers found in connective tissue are collagen (strong and flexible), elastic (stretchy and recoiling), and reticular (thin and branching).
- The three types of muscle tissue are skeletal (attached to bones, voluntary, striated), cardiac (found in the heart, involuntary, striated), and smooth (found in the walls of hollow organs, involuntary, non-striated).
- The two main types of cells in nervous tissue are neurons (transmit electrical impulses) and neuroglia (support and protect neurons).
Epithelial Tissue
Epithelial tissue is composed of tightly packed cells that form a continuous layer over all the free surfaces of the body, both external and internal. Epithelial tissue has several functions, such as protection, absorption, filtration, secretion, and sensation. Epithelial tissue also forms glands that produce various substances such as hormones, enzymes, sweat, and saliva.
Epithelial tissue can be classified based on two criteria: the shape of the cells and the number of cell layers. The shape of the cells can be squamous (flat), cuboidal (cube-shaped), or columnar (tall and narrow). The number of cell layers can be simple (one layer) or stratified (multiple layers). Some epithelial tissues have a third criterion: the presence or absence of cilia (hair-like projections) or microvilli (finger-like extensions) on the apical surface (the surface facing the lumen or external environment).
Some examples of epithelial tissues are:
- Simple squamous epithelium: a single layer of flat cells that lines the blood vessels, heart, lungs, and body cavities. It allows for diffusion, filtration, and secretion.
- Stratified squamous epithelium: multiple layers of flat cells that form the epidermis of the skin, the lining of the mouth, esophagus, anus, and vagina. It protects against abrasion, infection, and water loss.
- Simple cuboidal epithelium: a single layer of cube-shaped cells that forms the lining of the kidney tubules, ducts of glands, and surface of the ovaries. It functions in absorption and secretion.
- Stratified cuboidal epithelium: multiple layers of cube-shaped cells that form the ducts of sweat glands and mammary glands. It functions in protection and secretion.
- Simple columnar epithelium: a single layer of tall and narrow cells that lines the stomach, intestines, gallbladder, and uterine tubes. It functions in absorption, secretion, and movement of substances by cilia or microvilli.
- Stratified columnar epithelium: multiple layers of tall and narrow cells that form the lining of the pharynx, larynx, salivary glands, and male urethra. It functions in protection and secretion.
- Pseudostratified columnar epithelium: a single layer of cells with varying heights that gives the appearance of multiple layers. It lines the respiratory tract and parts of the male reproductive system. It functions in secretion and movement of substances by cilia.
- Transitional epithelium: a type of stratified epithelium that can stretch and change shape. It forms the lining of the urinary bladder, ureters, and part of the urethra. It functions in distension and contraction.
Connective Tissue
Connective tissue is composed of cells that are embedded in an extracellular matrix that consists of ground substance (a fluid or gel-like material) and fibers (collagen, elastic, or reticular). Connective tissue has several functions, such as protection, support, binding, storage, transport, and immunity.
Connective tissue can be classified based on the type and arrangement of fibers in the matrix. The main types of connective tissue are:
- Loose connective tissue: a type of connective tissue that has a sparse distribution of fibers and a high proportion of ground substance. It fills spaces between organs and tissues, cushions and protects organs, stores fat, and provides immunity. Examples are areolar tissue (found under epithelia), adipose tissue (found under skin and around organs), and reticular tissue (found in lymphoid organs).
- Dense connective tissue: a type of connective tissue that has a dense arrangement of fibers and a low proportion of ground substance. It provides strength and resistance to stress in different directions. Examples are dense regular tissue (found in tendons and ligaments), dense irregular tissue (found in skin and organ capsules), and elastic tissue (found in large arteries and some ligaments).
- Cartilage: a type of connective tissue that has a firm but flexible matrix composed mainly of collagen fibers embedded in chondroitin sulfate (a 51082c0ec5