Laboratory Exercise 2: Introduction to Histology PDF

Laboratory Exercise 2 Introduction to Histology Introduction Cell: basic unit of life Cellular arrangement gives body parts ability to perform certain tasks Form follows function! Histology: the study of the microscopic anatomy (microanatomy) of cells and tissues Goal: To create...

Laboratory Exercise 2 Introduction to Histology Introduction Cell: basic unit of life Cellular arrangement gives body parts ability to perform certain tasks Form follows function! Histology: the study of the microscopic anatomy (microanatomy) of cells and tissues Goal: To create accurate mental pictures of the body’s construction To learn to observe a 2D image and mentally construct a 3D image Tissue Types 1. Epithelial – coverings & linings 2. Muscle – contractible tissue that move structures to which they are attached 3. Nervous – specialized for communication & activity coordination 4. Connective – provides physical and functional support Epithelial Tissue Sheets/linings covering body surfaces Characteristics depend on activities that occur at a particular surface Simple vs. stratified Squamous vs. cuboidal vs. columnar Muscle Tissue Specialized for contraction due to presence of contractile, force-generating proteins, such as actin and myosin Three varieties of muscle: Skeletal: voluntary Smooth: involuntary Cardiac: involuntary; contained within heart Nervous Tissue Consists of both impulse-transmitting nerve cells, or neurons, and a group of supporting tissues, or glial cells Neurons contain 3 parts: 1. Cell body 2. Dendrites 3. Axon Connective Tissue Supports other tissues, both physically & functionally Cells widely separated by space containing gel & fibers 🡪 LARGE AMOUNTS OF EXTRACELLULAR FLUID (a.k.a., matrix)! Four types of connective tissue Connective Tissue Classification (4 Types) 1. Connective Tissue Proper Fibers arranged and suspended in a gel Gelatin: 3D molecular scaffold filled with water Nutrients & waste can move through water Gel can be rigid or fluid Fibers: thread-like structures that reinforce connective tissue Collagen most common Fibers can be tough or elastic Can be dense/fibrous or loose Adipose tissue = specialized type of loose connective tissue Connective Tissue Classification (4 Types) 2. Cartilage Cells called chondrocytes surrounded by semi-solid ground substance that imparts elastic properties Cartilage presence can vary across development: In fetus, forms precursor to many developing bones In adults, persists on bone surfaces at all moveable joints Connective Tissue Classification (4 Types) 3. Bone Bone cells = osteocytes Concentric layers of calcified material laid around blood vessels Intracellular material = mineralized (crystals of calcium salt deposited in gel) 4. Blood Classified as connective tissue because about half of its volume = extracellular fluid Using a Microscope 1) Plug in and turn on the microscope 2) Start with the stage in the lowest position and the objective lens at the lowest magnification setting 3) Place the slide on the stage and hold in place with the stage clip 4) Look through the eyepiece and use the coarse focus knob to raise the stage and bring the slide into view. The slide should not touch the lens 5) Use the fine focus knob until the image becomes clear 6) Adjust the light source, as needed, to gain a clearer view of the slide and move the slide gently around the stage in order to examine all of the slide 7) Twist the objective lens to the next magnification setting 8) Use the FINE FOCUS to adjust the image into clear view 9) When finished viewing a slide, lower the stage, turn objective lens to the lower magnification power, and remove slide For this lab, we will NOT use the highest magnification. If you need to move the Goals: To create accurate mental pictures of the construction of the body To be able to differentiate between different tissue types using histology as a tool