Presentation on theme: "Vertebrate Tissues Mrs. Stahl Zoology. Tissue A group or mass of similar cells working together to perform a common function. The study of tissues= Histology."— Presentation transcript:
Epithelial Tissue Covers or lines something and typically consists of sheets of cells that have surface specializations adapted for their specific roles. Functions: Size, shape, and arrangement directly relate to these specific functions – Absorb- lining of the intestines – Transport- Kidney tubules – Excrete- Sweat and Endocrine Glands – Protect- The Skin – Contain nerve cells for sensory reception- taste buds on the tongue.
to protect Classified based on thickness and shape
Classification of epithelia According to thickness – “simple” - one cell layer – “stratified” – more than one layer of cells (which are named according to the shape of the cells in the apical layer) According to shape – “squamous” – wider than tall – “cuboidal” – as tall as wide – “columnar” - taller than wide
Simple Columnar Single layer, elongated cells with the nucleus located in the same spot Function- protection, absorption, secretion Location- lining of the digestive tract and uterus, gall bladder – Some have fingerlike projections called microvilli which increase surface absorption – Contains scatter goblet cells functioning in the secretion of mucus
“ciliated” literally = eyelashes (see next page)
Stratified Squamous Multi-layered, thicker Function- protection Location- lining of body cavities like the mouth and outer layer of the skin, nasal cavity, esophagus, vagina, and anal canal (non-keratinized). Keratinized -> epidermis of the skin
Pseudostratified Columnar Stratified appearance but really a single layer with nuclei at various levels giving the layered look, ciliated, have goblet cells Function- secretion and cilia aided movement Location- lining air passages -> trachea, auditory tubes of the reproductive system
Special Features of Epithelium Cilia- hair-like appendages attached to the apical surface of cells that act as sensory structures or to proton movement Goblet Cells- specialized cells that produce mucus to lubricate and protect the surface of the organ. Villi- fingerlike projections that arise from the epithelial layer in some organs. Increase surface area allowing for faster and more efficient absorption Microvilli- smaller projections that arise from the cells surface. Increased surface area, bushy appearance.
Connective Tissue Characteristics: – Most abundant tissue in your body (made up of ground substance (fluid and semi-solid) and fibers – Binds structures together, stores nutrients, cells reproduce – Provides support, protection, framework, fills space, stores fat, produces blood cells, fights infection – Extracellular matrix- a bed of secreted organic material of varying composition that binds separated cells of tissue. Nonliving material between cells.
Classes of Connective Tissue: note the cell types and great variety of subclasses
2 General Types 1. Loose Connective Tissue: strong, flexible fibers of the protein collagen are interwoven with fine, elastic, and reticular fibers, giving its elastic consistency and binding capabilities. 2. Fibrous Connective Tissue: Densely packed collagen fibers and they may lie parallel to one another creating very strong cords (ex- tendons and ligaments) – Tendons- connect muscles to bones – Ligaments- connect bones to bones
Connective Tissue Originate from embryonic tissue called mesenchyme-> rises from the mesoderm, an embryonic germ layer (stem tissue)
Common Cell Types Adipocytes- adipose tissue cells Fibroblasts- most common, secrete collagen proteins that are used to maintain a structural framework, play an important role in healing wounds. Osteocytes- bone cells, are trapped within the bone matrix (the hard part of the bone), has tentacle like dendrites that allow it to maintain contact with neighboring cells / communicate.
Mast cells- tissue of the immune system of vertebrate animals. Mediate inflammatory responses-> allergic reactions. They are scattered all over the connective tissue. Chemical mediators produce responses-> inflammation, swelling, contraction of smooth muscles, increased mucus production
Adipose Large cells Function= protection, insulation, stores energy Location= beneath the skin, around kidneys, eyeballs, abdominal membranes
Cartilage Cells= chondrocytes Hard, flexible, supports ears, skeleton of sharks and rays Hyaline- most common, covers ends of bones and joints, respiratory passages Elastic- flexible and elastic, external ear, larynx Fibrocartilage- very tough, large, menisci (cartilage where two bones meet), intervertebral disks
Nervous Tissue Found in the brain, spinal cord and nerves Composed of: – Neurons- impulse conducting cells – Neuroglia- protection, support, and nourishment – Peripheral Glial Cells- form sheaths and help protect, nourish, and maintain cells of the peripheral nervous system (outside the brain and spinal cord)
Tissue Repair Regeneration- replaces dead or damaged cells with the same type of cell, restoring normal function Fibrosis- replaces damaged tissue with scar tissue, which holds the tissues together but does not restore normal functions.