BIOL 117 1st Edition Lecture 6Outline of Last Lecture I. Organelles - Nucleus- Endoplasmic Reticulum - Golgi complex - Lysosomes - Mitochondria II. Cytoskeleton - Microtubules (thickest)- Intermediate Filaments- Microfilaments (thinnest) Outline of Current Lecture I. From cells to Organ Systems - Tissues - Epithelial TissueII. Glandular Epithelia - GlandsIII. Connective TissueIV. Muscle TissueV. Nervous TissueCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.For most part cells do not flow around by themselves but rather attached to other cells creating tissue. Tissue is an ensemble of similar cells form the same origin that together carry out a specific function. Organs are formed by the functional grouping together of multiple tissues. There are 4 different types of tissues: 1. Epithelial tissue- forms boundaries between different environments, protects, secretes, absorbs, filters. Lining of digestive tract organs and other hollow organs. Skin surface 2. Connective tissue- supports, protects, binds other tissues together. Bones, tendons, fat and other soft padding tissue. Serves as a storage site for fat. 3. Muscle tissue- contracts to cause movement of substances through the body. Muscles attached to bones (skeleton), muscles of heart (cardiac), muscles of walls of hollow organs (smooth) 4. Nervous tissue – internal communication, responds to stimuli. Brain, spinal cord and nerves. CNS & PNS Epithelial Tissue – occurs in the body as covering or lining epithelium, or as glandular epithelium.Its functions are: - Protection - Absorption - Filtration- Excretion - Secretion - Sensory receptionAll epithelial tissues share two characteristics 1. A free surface that may be specialized for protection, secretion, or absorption. 2. Basement membrane is a noncellular layer that binds the epithelial cells to underlying connective tissue and helps the epithelial tissue resist stretching. Special characteristics of epithelia-cell junctions, such as polarity(directionally), specialized contacts (communication among cells) , supported by connective tissues, avascular, but innervated and can regenerate. There are three basic shapes of epithelial tissues to suit their functions:1. Squamous - is made up of flattened, or scale-like cells. It forms linings- in the blood vessels or lungs. Nucleus is very flat2. Cuboidal - is made up of cube-shaped cells. Found in many glands and in the lining of kidney tubules where provide some protection and are specialized for secretion and absorption. Nucleus is in the center3. Columnar – consists of elongated, column shaped cells, specialized for absorption and secretion. Nucleus close to the basement membrane. Epithelial cells have two parts to their name: these cells can be either simple (a single layer of cells) or stratified (multiple layer of cells). Single layer or flattened cells wit disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithella. It allows materials to pass by diffusion and filtration in sites where protection is not important: secretes lubricating substances in serosae. 1. Simple squamous/stratified – one layer or flattened cells, located in air sacs of lungs, heart, blood vessel linings/ several layers, located on surface of skin, lining of mouth andvagina, provides protection against abrasion and infection. 2. Simple cuboidal/stratified – one layer of cube-shaped cells, function as absorption and secretion/ two layers of cube-shaped cells, located in channels of mammary glands, sweat glands, function as protection3. Simple columnar/stratified - one layer of tall, slender cells, located in lining of gut and respiratory tract, function as absorption and secretion/ several layers, rare, located in urethra, function as protection. Gland is epithelial tissue that secretes a product. - Exocrine gland secretes their products into a channel leading to body surfaces, cavities, or organs. Ex: digestive enzymes, milk glands, sweat glands. - Endocrine gland lack channels and secretes their products, hormones into spaces just outside the cell. Connective tissue- many forms and functions, often serves as body’s glue, to bind and support the other tissues. It is the most abundant and widely distributed tissue in the body. All connective tissues contain cells embedded in an extracellular matrix. The matrix consists of protein fibers and noncellular material called ground substance. It might be solid (bone), fluid (blood), gelatinous (cartilage).- Cartilage – is tough but flexible. Serves as cushioning between certain bones and helps maintain the structure of certain body parts such as ears and the nose. Lacks blood vessels and nerves. Heals more slowly than bones. Three types: 1. Hyaline- most abundant, provides support and flexibility (drumstick) 2. Elastic – more flexible than hyaline because of the large amounts of wavy elastic fibers in its matrix. (external ear to provide strength and elasticity)3. Fibrocartilage – fewer cells than either hyaline or elastic. It forms cushioning layer in the knee joint as well as the outer part of the shock-absorbing disks between the vertebrae of the spine. - Bone- combination with cartilage and other components of joints, makes up the skeletal system. Bones are living things that metabolize tissue with a good blood supply that promotes prompt healing. Functions in support protection (by enclosing organs), and movement. - Blood – specialized connective tissue consisting of a liquid matrix, called plasma in ,which so called formed elements. The fibers in blood are soluble proteins. Found within blood vessels, transports nutrients, gases, hormones, wasters, fights infections. Muscle tissue - composed of muscle cells (muscle fibers) that contract when stimulated. There are 3 types: - Skeleton muscle tissue- attached to bones. When contracts, it moves a part of the body. Because skeleton muscle is under conscious control, it is describe as voluntary muscle. Long, cylinder-shaped cells. - Cardiac muscle tissue- found only in the walls of the heart where its contractions are responsible for pumping blood to the rest of the body. Involuntary muscles. - Smooth muscle tissue – is involuntary and is found in the walls of blood vessels and airways, where its contraction reduces the flow of blood or air. Found in the walls of organs such as stomach. Nervous