Zoology Unit 4: Multicellular Organization Lesson 4.1 PDF

ZOOLOGY UNIT 4 MULTICELLULAR ORGANIZATION Lesson 4.1: Tissue Mireille Joy D. Cayabo Subject Teacher Study Guide Zoology  UNIT 4: MULTICELLULAR ORGANIZATION Animal or...

ZOOLOGY UNIT 4 MULTICELLULAR ORGANIZATION Lesson 4.1: Tissue Mireille Joy D. Cayabo Subject Teacher Study Guide Zoology  UNIT 4: MULTICELLULAR ORGANIZATION Animal organization becomes more complex with increasing number of cells. The simplest animals are unicellular. They are complete organisms that carry all the basic life functions within the confines of one cell. Multicellular animals or the metazoans are more complex and have greater capacity for internal specialization than unicellular animals. There are five grades of organization that can be recognized in animals: (1) Protoplasm, (2) Cell, (3) Tissue, (4) Organ, and (5) Organ System. The first two grades of organization are found in unicellular organisms and the last three are found in the higher forms. The third grade of organization will be emphasized in this chapter. Lesson 4. 1 :Tissues o Epithelial Tissue o Connective Tissue o Muscular Tissue o Nervous Tissue Lesson 4. 2. Organs and Systems Lesson 4.3. Body Plan and Multicellular Animals At the end of this unit, you will be able to: a. Name the four major tissues types and their subcategories; b. Give the chief locations of the various tissue types in the body; and, c. Describe the process of tissue repair. Study Guide Zoology  UNIT 4. 1 :TISSUES A tissue is a group of similar cells, usually with a common embryonic origin, that function together to carry out specialized activities. Histology (hiss-TOL-o ̄ -je ̄ ; hist- tissue; -logy study of) is the science that deals with the study of tissues. A pathologist (pa-THOL-o ̄ -gist; patho- disease) is a physician who specializes in laboratory studies of cells and tissues to help other physicians make accurate diagnoses. One of the principal functions of a pathologist is to examine tissues for any changes that might indicate disease. The cells in multicellular animal may be divided into: (1) somatic cells or body cells constituting the individual animal throughout its life, and (2) germ cells, having to do only with reproduction and continuance of the species. There are four major groups of somatic tissues: (1) epithelial, (2) connective, (3) muscular, and (4) nervous. TYPES OF TISSUES Body tissues are classified into four basic types based on their structure and functions: 1.Epithelial tissue (ep-i-THE -le ̄ -al) covers body surfaces; lines body cavities, hollow organs, and ducts (tubes); and forms glands. 2.Connective tissue protects and supports the body and its organs, binds organs together, stores energy reserves as fat, and provides immunity. 3.Muscular tissue generates the physical force needed to make body structures move. 4.Nervous tissue detects changes inside and outside the body and initiates and transmits nerve impulses (action potentials) that coordinate body activities to help maintain homeostasis. EPITHELIAL TISSUE Epithelial tissue, or more simply epithelium (plural is ep- ithelia), may be divided into two types: covering and lining epithelium glandular epithelium o covering and lining epithelium forms the outer covering of the skin and the outer covering of some internal organs. o It also lines body cavities; blood vessels; ducts; and the interiors of the respiratory, digestive, urinary, and reproductive systems. o It makes up, along with nervous tissue, the parts of the sense organs for hearing, vision, and touch. o Glandular epithelium makes up the secreting portion of glands, such as sweat glands. Study Guide Zoology GENERAL FEATURES OF EPITHELIAL TISSUE General features of epithelial tissue include the following: Epithelium consists largely or entirely of closely packed cells with little extracellular material between them, and the cells are arranged in continuous sheets, in either single or multiple layers. Epithelial cells have an apical (free) surface, which is exposed to a body cavity, lining of an internal organ, or the exterior of the body; lateral surfaces, which face ad- jacent cells on either side; and a basal surface, which is attached to a basement membrane. In discussing epithelia with multiple layers, the term apical layer refers to the most superficial layer of cells, whereas the term basal layer refers to the deepest layer of cells. The basement membrane is a thin extracellular structure composed mostly of protein fibers. It is located between the epithelium and the underlying connective tissue layer and helps bind and support the epithelium (see Figure 4.1). Epithelia are avascular (a- without; vascular blood vessels); that is, they lack blood vessels. The vessels that supply nutrients to and remove wastes from epithelia are located in adjacent connective tissues. The exchange of materials between epithelium and connective tissue occurs by diffusion. Epithelia have a nerve supply. Because epithelium is subject to a certain amount of wear and tear and injury, it has a high capacity for renewal by cell division. Study Guide Zoology CLASSIFICATION OF EPITHELIUM CLASSIFICATION BY CELL ARRANGEMENT (LAYERS) ❖ SIMPLE EPITHELIUM (one layer of cell) Concerned with absorption, secretion and filtration. Very thin Protection is not one of their specialties. Simple Squamous Epithelium Single layer of thin squamous cells resting on a basement membrane. Air sacs of lungs, where oxygen and CO2 are exchanged Forms the walls of capillaries, where nutrients and gases pass between the tissue cells and the blood in capillaries. Simple Cuboidal Epithelium One layer of cuboidal cells resting on a basement membrane Common in glands and ducts (ex. Salivary glands and pancreas) Forms walls of the kidney tubules and covers the surface of the ovaries. Simple Columnar Epithelium Single layer of tall cells that fit closely together. Goblet cells, which produce a lubricating mucus, are often seen in this type of epithelium. Simple columnar epithelium lines the entire length of the digestive tract from the stomach to anus. STRATIFIED EPITHELIUM (more than one cell layer) Primary function: protection ❖ Stratified Squamous Epithelium Most common stratified epithelium in the body. Consists of several layers of cells Found in sites that receive a good deal of abuse or friction, such as the esophagus, the mouth, and the outer portion of the skin. ❖ Stratified Cuboidal Epithelium Two cell layers with (at least) the surface cells being cuboidal in shape. Rare in the body but found mainly in the ducts of large glands. Study Guide Zoology  ❖ Stratified Columnar Epithelium Columnar cell, but its basal cells vary in size and shape. Rare in the body but found mainly in the ducts of large glands. ❖ Transitional Epithelium Highly modified, stratified squamous epithelium that forms the lining of only a few organs – the urinary bladder, the ureters, and part of the urethra. As the cells are stretched, they become flatter, giving the appearance of stratified squamous epithelium. Because of its elasticity, transitional epithelium lines hollow structures that are subjected to expansion from within, such as the urinary bladder. It allows organs to stretch to hold a variable amount of fluid without rupturing. ❖ Gradual Epithelium The function of glandular epithelium is secretion, which is accomplished by glandular cells that often lie in clusters deep to the covering and lining epithelium. A gland may consist of one cell or a group of highly specialized epithelial cells that secrete substances into ducts (tubes), onto a surface, or into the blood. All glands of the body are classified as either endocrine or exocrine. The secretions of endocrine glands (EN-do ̄ -krin; endo- within; -crine secretion) enter the interstitial fluid and then diffuse into the bloodstream without flowing through a duct. These secretions, called hormones, regulate many metabolic and physiological activities to maintain homeostasis. The pituitary, thyroid, and adrenal glands are examples of endocrine glands. Exocrine glands (EK-so ̄ -krin; exo- outside;) secrete their products into ducts that empty at the surface of covering and lining epithelium such as the skin surface or the lumen (interior space) of a hollow organ. The secretions of exocrine glands include mucus, perspiration, oil, earwax, milk, saliva, and digestive enzymes. Examples of exocrine glands are sweat glands, which produce perspiration to help lower body temperature, and salivary glands, which secrete mucus and digestive enzymes. As you will see later, some glands of the body, such as the pancreas, ovaries, and testes, contain both endocrine and exocrine tissue. CLASSIFICATION BY THE SHAPE OF THE CELLS ❖ Squamous cells – flattened like fish scales ❖ Cuboidal cells – cube-shaped like dice ❖ Columnar cells – shaped like columns Study Guide Zoology Study Guide Zoology Study Guide Zoology Study Guide Zoology Study Guide Zoology Study Guide Zoology CONNECTIVE TISSUE ❖ Connects body parts ❖ Found everywhere in the body ❖ Most abundant and widely distributed of the tissue types. ❖ Functions: protecting, supporting, and binding together other body tissues. COMMON CHARACTERISTICS OF CONNECTIVE TISSUE ❖ Variations in blood supply Most connective tissues are well vascularized (good blood supply), but there are exceptions. Tendons and ligaments have a poor blood supply and cartilages are avascular. ❖ Extracellular matrix Connective tissues are made up of many different types of cells plus varying amounts of a nonliving substance found outside the cells Consists of protein fibers and ground substance, the material between the cells and the fibers. The extracellular matrix is usually secreted by the connective tissue cells and determines the tissue’s qualities. TYPES OF CONNECTIVE TISSUES 1. Bone – sometimes called osseous tissue, is composed of bone cells sitting in cavities called lacunae and surrounded by layers of a very hard matrix that contains calcium salts in addition to large numbers of collagen fibers. 2. Cartilage – less hard and more flexible than bone. Most widespread is hyaline cartilage, which has abundant collagen fibers hidden by a rubbery matrix with a glassy, blue white appearance. Other type of cartilage: fibrocartilage (forms the cushion-like disks between the vertebrae of the spinal column), elastic cartilage (found where a structure with elasticity is desired; support the external ear.) 3. Dense connective tissues – also called dense fibrous tissue, has collagen fibers as its main matrix element. It forms strong, rope-like structures such as tendons and ligaments. Tendons attach skeletal muscles to bones; ligaments connect bones to bones at joints. 4.Loose connective tissues – softer and have more cells and fewer fibers than any other connective tissue type except blood. 5. Areolar tissue – soft, pliable, “cobwebby” tissue that cushions and protects the body organs it wraps. It functions as a universal packing tissue and connective tissue ‘glue’. a soft layer of areolar connective tissue called lamina propria underlies all mucous membrane. Study Guide Zoology  6. Adipose tissue – commonly called fat. It is an areolar tissue in which fat cell predominate. Forms the subcutaneous tissue beneath the skin, where it insulates the body and protect it from extremes of both heat and cold. 7.Reticular connective tissue – consists of delicate network of interwoven reticular fibers associated with reticular cells, which resemble fibroblasts. Forms the stroma (literally, ‘bed’ or ‘mattress’), or internal framework, which support many free blood cells in lymphoid organs such as lymph nodes, the spleen, and the bone marrow. 8. Blood or vascular tissue – consists of blood cells, surrounded by a nonliving, fluid matrix called blood plasma. It is the transport vehicle for the cardiovascular system, carrying nutrients, wastes, respiratory gases, and many other substances throughout the body. Study Guide Zoology Study Guide Zoology Study Guide Zoology Study Guide Zoology Study Guide Zoology MUSCLE TISSUE ❖ Highly specialized to contract or shorten, to produce movement. ❖ Consists of elongated cells called muscle fibers that are highly specialized to generate force. As a result of this characteristic, muscular tissue produces motion, maintains posture, and generates heat. It also offers protection. TYPES OF MUSCLE TISSUE 1. Skeletal muscle tissue is named for its location— it is usually attached to the bones of the skeleton. 2. Cardiac muscle tissue forms the bulk of the wall of the heart. 3. Smooth muscle tissue is located in the walls of hollow internal structures such as blood vessels, airways to the lungs, the stomach, intestines, gallbladder, and urinary bladder. NERVOUS TISSUE ❖ it consists of only two principal types of cells: neurons and neuroglia. ❖ Neurons (neur- nerve, nerve tissue, nervous system) or nerve cells, are sensitive to various stimuli. They convert stimuli into nerve impulses (action potentials) and conduct these impulses to other neurons, to muscle fibers, or to glands. ❖ Neuroglia (noo-ROG-le ̄ -a; -glia glue) do not generate or conduct nerve impulses, but they do have many other important supportive functions. TISSUE REPAIR (WOUND HEALING) Tissue repair is the process that replaces worn-out, damaged, or dead cells. New cells originate by cell division from the stroma, the supporting connective tissue, or from the parenchyma (par-EN-ki-ma), cells that constitute the functioning part of the tissue or organ. Inflammation – a generalized (nonspecific) body response that attempts to prevent further injury. Immune response -extremely specific and mounts a vigorous attack against recognized invaders (bacteria, viruses, toxins) Tissue repair occurs in two major ways: by regeneration and by fibrosis. Regeneration – replacement of destroyed tissue by the same kind of cells Fibrosis – involves repair by dense connective tissue, formation of scar tissues. Study Guide Zoology  ACTIVITY 1 Match the tissue type to its function: ________1. Epithelial tissue a. Covers and lines surfaces ________2. Connective tissue b. Supports and binds other tissues ________3. Muscle tissue c. Contracts to produce movement ________4. Nervous tissue d. Transmits electrical signals Animal tissues: https://youtu.be/8IANWaZLIvg Intro to Histology: The Four Tissue Types | Corporis : https://youtu.be/S59JwFCjNhc To learn more about tissues, you can visit the following sites: 1. Khan Academy - Offers detailed videos and articles on animal tissues and their functions. o Khan Academy - Tissues 2. National Institutes of Health (NIH) - Provides research articles and resources related to tissue health and biology. o NIH - Research and Resources 3. Visible Body - An interactive platform featuring 3D models of human anatomy, including various tissue types. o Visible Body 4. TeachMeAnatomy - Comprehensive guides on tissues, including descriptions and visuals. o TeachMeAnatomy - Tissues 5. YouTube - Channels like CrashCourse and Armando Hasudungan provide engaging videos on tissues and their roles in the body. o CrashCourse Biology Study Guide Zoology  Chanco, C. R. General Zoology. 2nd Edition. Pasay City, Philippines, 2012. Marieb, E.N. Essentials of Human Anatomy and Physiology, 8th edition Marieb, E.N. Essentials of Human Anatomy and Physiology Laboratory Manual, 3rd edition Marieb, E.N. Essentials of Human Anatomy and Physiology Coloring Workbook, 8th edition Tortora, G.J. Introduction to the Human Body (anatomy and physiology, 8th edition) https://rsscience.com/wp-content/uploads/2022/04/classify-epithelial-tissue-shape- 1024x768.jpg?ezimgfmt=rs:361x271/rscb1/ng:webp/ngcb1 Study Guide Zoology