Lab 3 Tissues & Integumentary System PDF

**Lab 3. Tissues and the Integumentary System** **Introduction**: Review Chapters 4 and 5 in your text. This lab will reintroduce you to histology (the study of body tissues), and to our first organ system, the integumentary system. When we study organs and organ systems, we will see that these or...

**Lab 3. Tissues and the Integumentary System** **Introduction**: Review Chapters 4 and 5 in your text. This lab will reintroduce you to histology (the study of body tissues), and to our first organ system, the integumentary system. When we study organs and organ systems, we will see that these organs are a collection of different tissues. Conversely, when we study histology, we use samples taken from organs, therefore we must examine the organ carefully in order to study a particular tissue type. For example, we will look at a specimen collected from a kidney, which consists of different types of epithelial tissues and connective tissues, but we will only be looking for one particular type of epithelial tissue! *Tissues: Histology* A [tissue] is a collection of cells with a similar shape, function and embryonic origin. Some tissues include the non-living secretions made by the living cells, and in some cases you will see more non-living than living material! Animal tissues are derived from **four main tissue types, which are [epithelial, connective, muscle and nervous tissues].** As we\'ll see, no cells of these tissues look like the \"generalized cell\" that you studied in lab 2, but instead each cell type has a particular shape, size and contents reflects its specific function. we will study these tissues again and again when we encounter them as components of organ systems. Following are some examples of epithelial and connective tissues. Images of prepared tissues can look similar or confusing to the untrained eye. To better understand what you're seeing, compare these images to illustrations in the textbook and to some of the coloring for this week. [Epithelial tissue]: this tissue forms [coverings and glands]. It is always named by cell shape ([squamous, cuboidal, columnar and transitional]) and by the number of layers of cells ([simple, stratified or pseudostratified]). Some epithelial tissue cells are ciliated or have microvilli. Following are some examples Mammal simple squamosal epithelium, and simple cuboidal epithelium, sec., from mammal kidney, at 400x. Note how the simple squamosal cells are only a small part of the organ. You can identify them by their dark-stained, flattened nuclei (near tip of pointer). The nuclei of cuboidal cells are also visible, as dark, round structures within the pink cytoplasm. This is how our slides look in lab: Another shot of the same tissue with labels. Again, note the somewhat flat, dark-staining nuclei of the Bowman's capsule. It's easier to appreciate the cuboidal cells in this image, both the nuclei and the nucleoli are visible here, note the nice round nuclei of the cuboidal cells.  Human simple columnar epithelium, from human ileum. Note how the darkly-stained nuclei are relatively lined up and oval in shape. Here's a view from the lab. C:\\Users\\ah006\\Downloads\\IMG\_0055.jpg Here's a clearer image, with the cells and nuclei labeled:  [Connective tissue]: usually has a substantial non-living component which is secreted by the cells. The non-living component is called the matrix and in turn consists of fibers and ground substance. Differences among the secretions account for the different types of connective tissue. Following are some examples, hyaline cartilage, loose areolar connective tissue, Human hyaline cartilage. Here, the matrix and chondrocytes have been stained, allowing the lacunae to be seen. This is a photo taken from our lab. A somewhat clearer photo of hyaline cartilage with labels:  Loose, areolar connective tissue. This tissue has relatively few cells, the thick, pink fibers are collagen, and the darker fibers are elastic and reticular fibers. connective\_tissue\_loose\_areolar Here's another with labels:  Adipose tissue: this connective tissue is made up of fairly densely-packed adipocytes, there is very little matrix. Note the blood vessel near the center of this photo. AdiposeTissue2 A second image, labeled:  [Muscle tissue]: consists of three types of muscle, which vary in their location, structure, and control. These three types are [skeletal, cardiac, and smooth muscle]. We will cover this in lecture this week and later on in the semester when we cover the muscles on their own. [Nervous tissue]: is made up of [neurons], and several types of [neuroglia]. You will be introduced to nervous tissue this week but will delve much deeper into these cells later this semester. *The Integumentary System:* The largest organ in the body is the skin, also called the integument or cutaneous membrane. Like all membranes, it consists of two layers, one of which is epithelial tissue, the [epidermis], and the other connective tissue, the [dermis]. While not part of the integumentary per se, we also include a study of the subcutaneous layer, or [hypodermis]. The main functions of this organ include protection, thermoregulation, and sensation. *Skin Model*: Use this key to identify the structures on the model of the skin. [I. Epidermis] is labeled a -- e. It consists of stratified squamous epithelial tissue, mostly keratinocytes which contain a tough, water-resistant protein known as keratin. The accessory structures that are formed by the epidermis are the sebaceous glands, sudoriferous glands, hair follicles and nails (hair and nails are actually a type of glandular secretion). There is no blood supply that extends into the epidermis. From superficial to deep the layers of epidermis are labeled a -- e, and can be briefly described as follows: a\) the stratum corneum (dead keratinocytes), b\) stratum lucidum (found in thick skin of the plantar and palmar surfaces only), c\) stratum granulosum and d) stratum spinosum (dying keratinocytes) and e\) stratum basale (actively dividing keratinocytes and also melanocytes which contain the pigment melanin). [II. Dermis]. This layer of the cutaneous membrane consists mostly of dense, irregular connective tissue, with the main protein being collagen. It is divided into two regions, the superficial papillary region which has dermal papillae (labeled f), and the deeper reticular region. It also has embedded within it numerous accessory structures: Capillary bed, labeled r Encapsulated nerve endings, including Meissner's corpuscles (labeled w) and Pacinian corpuscles (labeled u) Naked nerve endings, labeled v, which are (sensory) dendrites or (motor) axons There are two types of sudoriferous glands, which secrete sweat: 1\) eccrine sudoriferous glands, labeled both h and j, are found in thick and in thin skin The sebaceous glands are labeled o and n; these secrete sebum (oil) B and C -- K is the hair follicle, associated with it is an arrector pili muscle, labeled x. [III. Hypodermis]. This is not technically part of the skin. It lies deep to the dermis and consists of adipose tissue, g. E:\\Human Anatomy Lab manual\\Anatomy lab manual images\\IMG\_0054.jpg