Tissues Tissues are a group of that perform a common function There are four major types of tissues in the human body:

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Eric Copeland
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1 Name: Per Date: Tissues Tissues are a group of that perform a common function There are four major types of tissues in the human body: _ Functions: Protection Secretion Excretion Two types: Covering the outer and inner surfaces of the body (). Form glands () Characteristics of Epithelium Cellularity: cells are with little or no extracellular materials (without blood vessels) Cells are attached to a Classification of Membranous Epithelium 1. Shapes: : flat, scaly or squished and platelike Cuboidal:, more cytoplasm than squamous : higher than they are wide, narrow and cylindrical Pseudostratified columnar: One layer of cells but all tops of cells do not reach the surface of the membrane 2. Layers: Simple: r : two or more layers of cells : tissue appears stratified but is acutally one layer of cells attached to a basement membrane Some may have cilia, microvilli, and keratin Simple Squamous Epithelial These cells show the characteristic of typical "squamous cells." The nucleus (A) is centrally located, the cell membrane

2 Name: Per Date: (C) is very thin, and the cell is filled with cytoplasm (B). Simple Cuboidal Epithelial These cuboidal cells (A) that line these tubules are as they are deep - cuboidal. The nuclei (B) are easily observed. Simple Columnar Epithelial These cells are not as wide as they are tall with the darkly stained nuclei (B) located at the base of the cells. The cell membranes (C) are very thin but easily identified. Glandular epithelium: Endocrine- substances are (i.e. hormones, thyroid) Exocrine- substances are (i.e. sweat glands, oil glands) Endocrine- Are called substances are diffused directly into the blood stream or interstitial fluid (i.e. hormones, thyroid) Glandular epithelium: Exocrine- substances are secreted into ducts (i.e. sweat glands, oil glands) ---- Three types Apocrine release product into a duct by (damage to cell) Mammary glands Holocrine when releasing product. () Sebaceous glands Merocrine Discharge their secretion product directly through the cell or plasma membrane () Salivary glands CONNECTIVE TISSUE CHARACTERISTICS OF CONNECTIVE TISSUE (intercellular material) Fibers () Cells (fibroblasts, macrophages, blood)

3 Name: Per Date: Proteoglycans Ground substance () NEED TO KNOW CELL TYPE OF EACH TISSUE AND FIBERS!!!!!!!! CLASSIFICATION OF CONNECTIVE TISSUE Fibrous Bone Cartilage Blood FIBROUS CONNECTIVE TISSUE Predominantly consists of Four subtypes: Loose (Areolar) Reticular Dense Adipose (Fat) Areolar Tissue In the watery matrix (ground substance) observe the nuclei of fibroblasts (A), collagen fibers (B) and elastic fibers (C). Reticular Connective Tissue The reticular fibers (A) form a network or lattice in this spleen tissue. Dense Connective Tissue The fibroblasts (A) are more clearly observed between the parallel collagenous fibers (B). Adipose Tissue BONE Bone In the compact bone micrograph at the left, several complete osteons are visible. In the center of the osteon is the central canal (A) which hold the blood vessels and a nerve. These canals are surrounded by concentric rings of inorganic matrix, the lamellae (B). Between the lamellae are bone cells, the osteocytes (C) located in lacunae. CARTILAGE Hyaline Cartilage Fibrocartilage ELASTIC CARTILAGE BLOOD Blood Contains no fibers or ground substance Matrix Plasma (liquid) Formed elements Erythrocytes (red blood cells)

4 Name: Per Date: Leukocytes (white blood cells) Thrombocytes (platelets) Blood Tissue Note the red blood cells, platelets, and leukocytes located within this slide. NEUTROPHIL This granulocyte has very tiny light staining granules. The nucleus is frequently multi-lobed. These cells are capable of phagocytizing foreign cells, toxins, and viruses. Normally, neutrophils account for 50-70% of all leukocytes. EOSINOPHIL This granulocyte has large granules (A) The nucleus often has two lobes. (Does it looks like a telephone receiver?) The granules contain digestive enzymes that are particularly effective against parasitic worms in their larval form. These cells also phagocytize antigen - antibody complexes. These cells account for less than 5% of the WBC's. BASOPHIL The granules in this cell are large, stain deep blue to purple, and often mask the nucleus. These granules contain histamines (cause vasodilation) and heparin (anticoagulant). They represent less than 1% of all leukocytes. LYMPHOCYTE The lymphocyte is an agranular cell with very clear cytoplasm. Its nucleus is very large for the size of the cell. This cell is much smaller than the three granulocytes (which are all about the same size). These cells play an important role in our immune response. The T-lymphocytes act against virus infected cells and tumor cells. The B-lymphocytes produce antibodies. This is the second most numerous leukocyte, accounting for 25-35% of the cells. MONOCYTE ERYTHROCYTES THROMBOCYTES - PLATELETS Platelets, which are cell fragments, are seen next to the "t's" above. Platelets are important for proper blood clotting. Each cubic millimeter of blood should contain 250,000 to 500,000 of these. CLASSIFICATION OF TISSUE MUSCLE MUSCLE TISSUE Muscle Skeletal Smooth Cardiac Skeletal Muscle Tissue Skeletal muscle cells run the full length of a muscle. Line A show the width of one cell (fiber). Note the striations ( stripes ) characteristics of this muscle type. These cells are multicellular, B marks one nucleus. Smooth Muscle Tissue

5 Name: Per Date: Smooth muscle cells are spindle shaped and uninucleate. (B). Cardiac Muscle Tissue Cardiac muscle cells branch, are striated, are uninucleate (B) and have intercalated discs (A). CLASSIFICATION OF TISSUE NERVOUS NERVE TISSUE Nerve Neurons Neuroglia (glial cells) Nervous Tissue The nerves that carry the stimuli that cause your body's muscles to contract at MOTOR neurons. Their structure is different from sensory neurons. The cell body or perikaryon (A) is filled with chromatophilic substances which pick up the stain in this micrograph. The cell's axon can not be distinguished from its dendrites in the micrograph. B marks the axon and dendrite threads. The "C's" marks the neuroglia cells (dark spots) and the neurofibrils.

The Tissue Level of Organization

The Tissue Level of Organization Tissues A groups of similar cells, usually having similar embryonic origin and specialized function Histology: the study of tissues Four general types Epithelial Muscle