GENBIO Tissues PDF

Tissues Emily Mharl M. Ruiz, LPT Teacher II Benigno S. Aquino National High School Lesson 4: Cell Types  Objectives: At the end of the learning period, student should be able to: a. classify different cell types (of plant/animal tissue) and specify the function...

Tissues Emily Mharl M. Ruiz, LPT Teacher II Benigno S. Aquino National High School Lesson 4: Cell Types  Objectives: At the end of the learning period, student should be able to: a. classify different cell types (of plant/animal tissue) and specify the functions of each; b. make a concept map that shows the different plant and animal cells and tissues; and c. relate cell and tissue functions for the organism’s over-all functions.  TISSUE Tissue An aggregation of cells and cell products of similar structure, origin and performs a common function  TISSUE Tissue An aggregation of cells and cell products of similar structure, origin and performs a common function  Epithelial Tissue –Covers surfaces –Has little extracellular material –Usually has a basement membrane –No blood vessels Locations: Body coverings Body linings Glandular tissue Functions: Protection Absorption Filtration Secretion Epithelium Characteristics Cells fit closely together and often form sheets The apical surface is the free surface of the tissue The unattached surface Can be exposed to exterior or cavity of an organ The lower surface of the epithelium (the basal lamina) rests on a basement membrane Consists of reticular connective tissue Avascular (no blood supply) Relies on circulatory system to obtain food and oxygen Surrounding connective tissues supply via diffusion from nearby capillaries Regenerate easily if well nourished (through normal cell division) Those on the exterior of the skin are exposed to friction and other hostile substances and are therefore lost © 2015 Pearson Education, Inc.  Classification of Epithelia Names using number of cell layers Names using shape of cells Simple epithelium has one layer of cells Stratified epithelium has more than one cell layer Squamous are flat and thin Pseudostratified epithelium has one layer, but Cuboidal are cube-like appears to have two or more layers Transitional epithelium is stratified epithelium that can Columnar are tall and thin be greatly stretched Epithelial Tissue Functions Epithelial Tissue Functions 1. Protecting underlying structures – Example: outer layer of skin and oral mucosa 2. Acting as barriers – Example: outer layer of skin 3. Permitting the passage of substances – Example: epithelium in the lungs 4. Secreting substances – Example: mucous glands and sweat glands 5. Absorbing substances – Example: epithelial cells of the intestine  Connective Tissue Main function: binding and support other tissues Large amount of extra- cellular matrix with fewer cells Connective tissue cells secrete the extra- cellular matrix Extracellular matrix consists of network of fibers in liquid, jelly- like or solid matrix Connective Tissue Extracellular matrix contains Protein fibers Collagen fibers are flexible but resist stretching Reticular fibers form a fiber network Elastic fibers recoil Ground substance Proteoglycans in ground substance hold water, enabling connective tissues to return to their original shape after being compressed Fluid Connective Tissue Matrix- Protein Fibers Strengthens and supports connective tissue Collagen Fibers Strong, resist pulling forces, flexible Made of the protein collagen which is the most abundant protein in your body Elastic Fibers smaller in diameter than collagen fibers, branch to form network Made of the protein elastin Reticular Fibers Provide support for the walls of blood vessels Made of collagen with a glycoprotein covering Connective Tissue Consist of cells separated from each other by abundant extracellular matrix Functions 1. Enclosing and separating 2. Connecting tissues to one another (Ex. Ligaments and Tendons) 3. Supporting and moving (Ex. Bones and cartilage) 4. Storing (Ex. Adipose tissue and Bones) 5. Cushioning and insulating (Ex. Adipose tissue) 6. Transporting (Ex. Blood) 7. Protecting (Ex. Blood and Bones) Connective Tissue Cells Fibroblasts – large flat cells with branching processes. Migrate throughout connective tissue secreting the fibers and ground substance Macrophages – develop from white blood cells. Surround and engulf material by phagocytosis Mast Cells – alongside blood vessels that supply connective tissue. Produce histamine – a chemical that dilates blood vessels. Adipocytes – “fat cells” store triglycerides.  Types of Connective Tissue Loose Connective Tissue Fibers are loosely intertwined among many cells. 3 types of loose connective tissue Areolar Connective Tissue – one of the most widely distributed connective tissues in the body. Contains fibroblasts, macrophages, plasma cells, mast cells, adipocytes and a few white blood cells Helps to form the subcutaneous layer Adipose Tissue – The cells, called adipocytes, are specialized for storage of triglycerides. Adipocytes fill up with a large fat droplet, so the nucleus gets pushed to one side of the cell. Used for insulation, protection and as an energy reserve Reticular Connective Tissue – made of interlacing reticular fibers and reticular cells that connect to each other to form a network. Used to bind together smooth muscle cells and to filter out worn out blood cells and bacteria  Types of Connective Tissue Dense Connective Tissue Contains more numerous, thicker and denser fibers but fewer cells than loose connective tissue. 3 types: Dense regular connective tissue Dense Irregular connective tissue Elastic connective Tissue  Dense Regular Dense Irregular Elastic Bundles of collagen Collagen fibers are Contains fibers are arranged packed closely together regularly in parallel in an irregular, random branching elastic patterns that give it pattern fibers and strength. Found in parts of the fibroblasts Withstands pulling from body where pulling the ends, but unravels forces are exerted in Yellowish in color when pulled from the various directions side Strong, can regain Usually found in sheets Silvery white in shape after appearance. Tough and Examples: Dermis of the skin, heart valves, stretching pliable perichondrium and Found in tendons and periosteum Found in lungs ligaments and arteries  Cartilage Cartilage Dense network of collagen fibers and elastic fibers embedded in chondroitin sulfate (a rubbery component of the ground substance) Can withstand more stress than the dense and loose connective tissue. Collagen fibers make the tissue strong; chondroitin sulfate makes it resilient Chondrocytes – mature cartilage cells Lacunae – holes in the matrix in which the cells sit Perichondrium – dense irregular connective tissue that surrounds cartilage 3 types – hyaline, fibrocartilage and elastic Cartilage is AVASCULAR and NO nerve supply (but the perichondrium does)  Hyaline Elastic Fibrocartilage Cartilage Cartilage Gel like ground Chondrocytes Chondrocytes substance, collagen fibers (not visible with scattered among located in a normal stains) and visible bundles of threadlike network prominent chondrocytes collagen fibers of elastic fibers Most abundant cartilage in the body No perichondrium Provides strength, Found at the end of long Strongest of the 3 elasticity and bones to cushion joints maintains the and at epiphyseal plates types of cartilage (growth plates in bones) shape of certain Found in the structures (like the Weakest of the 3 types intervertebral discs of cartilage external ear) Bone Tissue (Osseous tissue) 2 types – compact and spongy Compact Osteon – basic unit of compact bone Lamellae – concentric circles of matrix Lacunae – spaces in the matrix that house cells Osteocytes – mature bone cells Spongy Trabeculae – columns of bone with spaces filled with red bone marrow Blood Tissue Connective Tissue with a liquid matrix Red Blood Cells (erythrocytes) – transport oxygen White Blood Cells – function in immunity Neutrophils, Eosinophils, Basophils, T and B leukocytes, natural killer cells and Monocytes Platelets – participate in blood clotting Muscle Tissue Muscle is a highly cellular and vascular tissue specialized for contraction via the interaction of myofilaments (between thin and thick filaments ) ; it is responsible for movement of the body and for changes in the size and shape of internal organs. There are three basic types of muscle tissue (skeletal, smooth, and cardiac) classified according to appearance of their contractile cells and location. Muscle Tissue Specialized to contract, or shorten, making movement possible – Length of muscle cells is greater than the diameter – Sometimes called muscle fibers because they often resemble tiny threads Three types of muscle tissue – Skeletal Meat of animals Constitutes ~40% of a person’s body weight Attaches to the skeleton and allows for movement Voluntary, multinucleated, and striated (banded) – Cardiac Muscle of the heart Connected to one another by intercalated disks (contain gap junctions) Involuntary, striated, and usually have one nucleus per cell – Smooth Forms the walls of hollow organs (except the heart) and also is found in the skin and the eyes Involuntary, not striated, and have a single nucleus Muscle Tissue Smooth Muscle Nervous Tissue Nervous tissue is specialized to conduct action potentials (electrical signals) Neurons conduct action potentials Neuroglia support the neurons Tissue Type Epithelial Connective Muscle Nerve Cell Shape Flattened, Irregular or round Elongated Cell appendages cuboidal, branched columnar Cell Single Scattered in In sheets or Isolated or Arrangement multilayered matrix bundles networked Location Body covering or Supports other Lining internal Concentrated in lining organs or organs organs, make brain and spinal cord cavities skeletal muscles + all over the body Surface Feature Cilia, microvilli of Cells - - - Matrix Type Basement Varied – protein membrane fibers + liquid, - - gelatinous, firm to calcified Matrix Amount Minimal Extensive Absent Absent Unique Feature No direct blood Cartilage has no Can generate Can generate supply, except for blood supply electrical signals, electrical signal glands force and movement  Meristems Meristems are regions of cell division Plants could keep growing their entire lives Possible to grow a new plant from a cutting Present in tips and roots of the plant  Simple Tissues Parenchyma – thin walled & alive at maturity; often multifaceted. Collenchyma – thick walled & alive at maturity Sclerenchyma – thick walled and dead at maturity – Sclerids or stone cells – Fibers Epidermis – alive at maturity – Trichomes – “pubescence” or hairs on epidermis – Root Hairs – tubular extensions of epidermal cells Epidermis single-layered group of cells that covers the leaves, stems and roots of a plant Parenchyma Round, polygonal or elongated Thin cell wall Dense cytoplasm, small nucleus and a large vacuole Location: leaves, stems and roots Parenchyma Functions Maintains shape and firmness of plants Store and absorb food Metabolically active Allows gas exchange Collenchyma Elongated in shape Present in dicot’s stem and petiole Provides mechanical support and elasticity Sclerenchyma Composed of dead cells Presence of lignin Location: stems, veins of leaves Right-hand illustration modified from: Weier, Stocking & Barbour, 1974, Botany: An Introduction to Plant Biology, 5th Ed. ,roots FIBERS Functions: protection, gives strength, rigidity, elasticity and flexibility Can withstand strains and pressure Complex Tissue 1.Xylem – water conducting tissue 2.Phloem- food conducting tissue Xylem Vascular tracheids and vessels element (bounded by thick lignified. Vessels are very long tube-like structures formed by a row of cells placed end to end. They conduct water). Functions: carry water & minerals salts upward from the root to different parts of shoots. Since walls of tracheid, vessels of xylem are lignified, they give mechanical strength to the plant body. Phloem Two types : 1. Sieve tubes 2.Companion cells Functions-transport prepared food materials from the leaves to the storage organs & later from storage organs to the growing regions of the plant body.  Vascular Bundles with xylem & phloem Maize or Corn – vein in cross Alfalfa – vein in cross section section  Tissues Emily Mharl M. Ruiz, LPT Teacher II Benigno S. Aquino National High School