Tissues to Know for BIO 163 Lab PDF

**[Tissues to know for BIO 163 Lab]** For each of the following tissues you should: 1. Be able to identify the tissue and any important cells and structures in the tissue. **Epithelial tissues**: form protective coverings and function in secretion and absorption **Connective tis...

**[Tissues to know for BIO 163 Lab]** For each of the following tissues you should: 1. Be able to identify the tissue and any important cells and structures in the tissue. **Epithelial tissues**: form protective coverings and function in secretion and absorption **Connective tissues:** support soft parts and bind structures together **Muscular tissues:** produce body movement **Nervous tissue:** conduct impulses to control and coordinate body activities 2. Know the function of the specific tissue. 3. Know locations in the body where the tissue is found **[Epithelial]** Cell shapes: squamous (thin and flattened), cuboidal (cube-shaped), or columnar (tall and elongated) Number of layers: simple (1 layer) and stratified (2 or more layers) **Function:** Protection, secretion, absorption, excretion **Location:** Cover body surface, cover and line internal organs, compose glands **Characteristics:** Lack blood vessels, readily divide; cells are tightly packed **[Connective]** **Function:** Bind, support, protect, fill spaces, store fat, produce blood cells **Location:** Widely distributed throughout body **Characteristics:** Most have a rich supply of blood, with at least two distinct cell types; cells are farther apart than epithelial cells with extracellular matrix in between **[Muscle]** **Function:** Movement **Location:** Attached to bones, in the walls of hollow internal organs, heart **Characteristics:** Able to generate force in response to specific stimuli **[Nervous]** **Function:** Conduct impulses for coordination, regulation, integration, and sensory reception **Location:** Brain, spinal cord, nerves **Characteristics:** Cells communicate with each other and other body parts by receiving and sending stimuli **[Epithelial Tissues]** **[Simple squamous: ]** - Made up of a single layer of thin, flattened cells - Cells are tightly packed together - Cells have broad, thin nuclei - Due to flattened structure of cells, this type is found in diffusion and filtration sites - Because it is suited for diffusion, it functions in the exchange of gases in the alveoli of the lungs, and lines blood and lymph vessels, as well as body cavities - It is very delicate, and can be damaged easily **[Simple cuboidal:]** - Consists of a single layer of cube-shaped cells with centrally located nuclei - Lines most kidney tubules, covers ovaries, and lines ducts of some glands - Functions in urine formation in the kidneys, and glandular secretion - When it lines tubules or ducts, free surface faces lumen, a hollow channel **[Simple columnar:]** - Made up of one row of tall, elongated cells - Nuclei are located near the basement membrane - Cells may be ciliated or nonciliated - Nonciliated cells line the uterus, stomach, and intestines, where they protect underlying tissues, secrete digestive fluids, and absorb nutrients - Cilia are long extensions from the free surfaces of certain cells; they beat in a certain direction to move cells or mucus - Ciliated cells are found in the uterine tubes, and help move egg cells toward the uterus - Some cells contain tiny microvilli (smaller than cilia) to increase surface area for absorption - Goblet cells are scattered among the cells; secrete mucus onto the free surface of the tissue for lubrication or protection **[Stratified Squamous:]** - Made up of many layers of flattened cells, designed to protect underlying layers - Named for the shape of the outermost layers of cells, which are composed of squamous cells - Cuboidal cells in the deeper layers divide, and push the older cells outward, where they begin to flatten - Makes up the outer layer of skin (epidermis), and lines the mouth, esophagus, vagina, and anal canal - In the skin, outer layers of cells undergo keratinization, producing a dry, water-proof, protective layer, in which outer cells are dead - Keratinization does not occur in areas in which tissues remain moist and alive: oral cavity, esophagus, vagina, or anal canal **[Pseudostratified Columnar:]** - Cells appear layered due to the varying positions of their nuclei within the row of cells, but are not truly layered - Cells vary in shape - All cells reach basement membrane, but not all reach free surface - Most cells have cilia along their free surface - Goblet cells are scattered among the epithelial cells; secrete mucus - Found in the passageways of the respiratory system - In the respiratory tract, the mucus traps microorganisms and dust, and the cilia sweep them away from the airways **[Transitional:]** - Designed to distend (stretch) and return to its normal size, in response to changing tension - Found in the linings of the urinary bladder, urethra, and ureters - Upon contraction of a wall of one of these organs, the tissue is composed of several layers of cells of irregular shape - Upon distension, the cells become elongated - Functions as an expandable lining, and prevents urine from diffusing back into the internal environment **[Connective Tissue Proper]** **[Areolar : LOOSE]** - Forms thin, delicate membranes - Main cell type is fibroblasts - Matrix consists of a gel-like ground substance containing collagen and reticular fibers - Locations: binds skin to underlying tissues, under most epithelial layers, between muscles **[Reticular connective tissue:]** LOOSE - Contains thin, reticular fibers - Fibers form a 3-dimensional network - Forms a framework for certain internal organs (liver, spleen) **[Dense :]** - Consists of densely packed collagen fibers and a network of elastic fibers - Contains few cells; most are fibroblasts - Due to strength of collagen fibers, the tissue can withstand pulling forces - Has a poor blood supply, so heals slowly - Found in tendons, ligaments, deep layer of skin, and the white layer of the eyeball (sclera) **[Adipose: LOOSE]** - Contains adipocytes, which store fat in cytoplasm - Found under skin, between muscles, around kidneys, around abdominal membranes, behind eyeballs - Functions: Cushions joints & organs, stores energy, insulates body **[Specialized Connective Tissues]** **Bone** - The most rigid connective tissue, due to presence of mineral salts (calcium salts) - Collagen fibers within the matrix provide some flexibility - Bone supports and protects many body structures in cranial & thoracic cavities - Forms sites for muscle attachments - Site of blood cell formation (red bone marrow) - Stores and releases chemicals, such as calcium and phosphorus - 2 types of bone tissue: compact and spongy - Structure of compact bone: - Bone cells, called osteocytes, lie within lacunae (chambers) - Matrix is arranged in concentric circles (lamellae) around central or Haversian canals - Cylindrical units are called osteons or Haversian systems - Central canals contain blood vessels, and distribute blood to the cells through tiny tubes called canaliculi - Bone has a good blood supply, enabling rapid recovery after an injury **[Blood]** - Functions to transport substances throughout the body - Transports substances between interior cells and cells that exchange nutrients, gases, and wastes with the environment - Composed of formed elements suspended in a liquid matrix called plasma. - Formed elements include red blood cells to carry oxygen, white blood cells for protection against infection, and platelets for blood clotting - Most blood cells are produced by the red bone marrow within certain long bones **[Hyaline cartilage]** - The most common type of cartilage - Contains fine collagen fibers in matrix; appears glassy - Found on the ends of bones, supports respiratory structures and passages, also important in embryonic development of many bones and bone growth **[Elastic cartilage: ]** - Contains elastic fibers in dense network; flexible - Provides framework for the external ears and parts of the larynx **[Fibrocartilage]** - Tough tissue containing many collagenous fibers - Good shock absorber - Found in intervertebral discs, knees and pelvic girdle **[Muscle tissue]** **[Skeletal muscle]** - Makes up muscles that attach to bones - Voluntary; can be controlled by conscious effort - Cells (fibers) are long and cylindrical, striated (have a striped appearance), have many nuclei - Cells contract only when stimulated by nerve cells (neurons) - Skeletal muscles move head, trunk, and limbs **[Smooth muscle]** - Named because smooth muscle cells lack striations - Cells are spindle-shaped, with 1 central nucleus - Involuntary, since it cannot be stimulated to contract with conscious effort - Found in the walls of hollow internal organs, such as in the digestive tract, blood vessels, and urinary bladder **[Cardia muscle]** - Found only in the heart - Consists of branching cells (fibers), each with a single nucleus - Cells form branching networks - Cells are connected to each other by intercalated discs, containing special gap junctions that send impulses from cell to cell - Involuntary; cannot be controlled by conscious effort - Striated; has a striped appearance - Makes up most of the heart - Pumps blood through heart and into blood vessels **[Nervous tissue]** - Found in the brain, spinal cord, and nerves - Neurons, or nerve cells: - Cells that respond to certain types of environmental stimuli or changes, by conducting electrical impulses to other neurons, muscles, and glands - Consist of a soma (cell body), and cellular processes (extensions), called dendrites (receive stimuli) and axons (send out signals) - Coordinate and regulate body functions - Neuroglia (nerve glue): - Cells that support, nourish, and communicate with neurons, but do not conduct impulses - Bind nervous tissue together, conduct phagocytosis **[Glands]** - Organs composed of epithelial tissues - Made up of cuboidal or columnar cells - Produce and secrete substances into ducts or into body fluids: - Glands that secrete products into ducts that open to a body surface are exocrine glands - Glands that secrete products into body fluids or blood are endocrine glands **Exocrine glands** are classified by the ways the glands secrete their products: **Merocrine (eccrine) glands** are the most common type; release fluid products by exocytosis: Some are serous; produce a watery serous fluid, sometimes with high enzyme concentration Others are mucous; produce a thicker, protective substance (mucus) Examples: pancreas, salivary glands, and sweat glands **Apocrine glands** Cellular product and portions of the free ends of glandular cells pinch off during secretion; example: mammary glands **Holocrine glands** release entire cells that disintegrate to release their secretions; example: sebaceous (oil) glands Cell Types - **Fibroblasts:** most common fixed cell type; large, star-shaped cells that secrete fibers - **Macrophages (histiocytes)**: function as phagocytes; defend against infection and foreign particles - **Mast cells**: large, fixed cells, located near blood vessels; release heparin (anticoagulant) and histamine (promotes inflammation)