Human Anatomy and Physiology I Lab 4: Classification of Tissues (PDF)

Human Anatomy and Physiology I Laboratory BSC 2085L Lab 4: Classification of Tissues, Part II EXERCISE 6A: CLASSIFICATION OF TISSUES Tissues are groups of cells that are similar in structure and function. The study of tissues is called histology. There are four pri...

Human Anatomy and Physiology I Laboratory BSC 2085L Lab 4: Classification of Tissues, Part II EXERCISE 6A: CLASSIFICATION OF TISSUES Tissues are groups of cells that are similar in structure and function. The study of tissues is called histology. There are four primary types of tissues in the human body: epithelial, connective, muscle and nervous. Each tissue type has distinctive structures, patterns, and functions. As you progress through Human Anatomy and Physiology, you will see that tissues are structurally and functionally connected to other tissues in organs. The purpose of Exercise 6 is to learn each of the four primary tissue types and their various subcategories. Read Exercise 6 in your lab manual (and chapter 4 in your textbook) for more information about these tissues. Look at the figures in your lab manual for pictures of each of the tissues listed below and examine slides of each tissue indicated with an asterisk (*) in this lab handout. If the slide looks different from the picture in your textbook, draw it! These slides will be used on next weeks lab quiz. Objectives: Complete Activities 2 and 4: Connective Tissue and Nervous Tissue Upon completion of this lab, you should be able to: recognize and name each tissue type: primary name and subcategory name describe its functions know where the tissue is found in the body name the cells in each type of tissue name the special structures in each tissue: example = fibers present, goblet cells, microvilli, etc. I. Connective Tissue (most abundant tissue in the body by weight) - function to protect, support and bind together other tissues of the body - cells are located in an extracellular matrix of fibers and ground substance (Figure 6.4) - blood vessels are present in all connective tissue (except cartilage) - all connective tissue comes from the same embryonic tissue known as mesenchyme (Figure 6.5a) - there are four classes of connective tissue: connective tissue proper, cartilage, bone, and blood A. Connective Tissue Proper - fibroblasts make connective tissue proper; secrete collagen and elastin protein - there is loose connective tissue proper and dense connective tissue proper *1. Areolar tissue (Figure 6.5b) - widely distributed: thin membranes throughout body, beneath the skin and most epithelium, between muscles a. cells: 1. fibroblasts = produce protein fibers 2. macrophages = defend from infection by phagocytizing foreign particles 3. mast cells = release histamine and heparin in an inflammatory response b. fibers: 1. collagen = bundled together as thick “white” fibers; provide high tensile strength 2. elastic = long thin “yellow” fibers; stretch easily and retain shape (stain black under the microscope) *2. Adipose tissue (Figure 6.5c) - stores fat for energy, protection, insulation  *3. Reticular tissue (Figure 6.5d) - fibers form a soft internal skeleton that supports other cell types - found in the liver, spleen and lymphatic organs; example slide = liver* a. fibers: reticular = similar to collagen fibers; form branching networks *4. Dense regular connective tissue (Figure 6.5e) - closely packed bundles of collagen fibers running in parallel directions; some elastic fibers - tough, pliable, resists stress from one direction - fibroblasts present secrete collagen fibers - found in tendons and ligaments - example slide = yellow elastic tissue* *5. Elastic Connective Tissue (Figure 6.5f) - Dense regular connective tissue with a high proportion of elastic fibers - Allows tissue to recoil after being stretched - found in the walls of major arteries *6. Dense irregular connective tissue (Figure 6.5g) - thicker bundles of collagen fibers running in many different directions - resists tension from many directions; gives strength - fibroblasts present secrete collagen fibers - found in the dermis of the skin B. Cartilage - there are three types of cartilage: hyaline, elastic, and fibrocartilage - extracellular matrix is a gel-like ground substance (made of proteoglycans) that provides resilience; collagen and elastic fibers provide strength a. cell type: chondroblasts = secrete cartilage matrix chondrocytes = maintain cartilage matrix; live in lacunae *1. hyaline cartilage (Figure 6.5h) - most abundant type of cartilage - found in the trachea and larynx, covers the ends of long bones in joints, forms costal cartilage of ribs, and in the nose - has resilient cushioning properties; decreases friction (in joints) *2. elastic cartilage (Figure 6.5i) - has many elastic fibers; has a greater tolerance to repeated bending - found in the outer ear and epiglottis *3. fibrocartilage (Figure 6.5j) - contains bundles of collagen fibers - tough; acts as a shock absorber - found in the intervertebral discs, pubic symphysis, and discs of knee joint  *C. Bone (Figure 6.5k) - also known as osseous tissue - function to support and protect the body - extracellular matrix is made of collagen fibers and mineral salts (hydroxyapatite) - lamellae: concentric layers of matrix surrounding osteonic canals a. cells type: osteoblasts = secrete bone matrix osteocytes = maintain bone matrix; live in lacunae *D. Blood (Figure 6.5l) - most atypical connective tissue - extracellular matrix is fluid blood plasma a. cells: 1. red blood cells = carry gases 2. white blood cells = fight infection 3. platelets = clot blood II. *Nervous Tissue (Figure 6.6) - found in the brain, spinal cord and peripheral nerves a. cells: 1. neurons = transmit electrical impulses throughout the body 2. neuroglial cells = support, bind, and provide nutrition for neurons