Tissues grade 11


 Epithelial tissue forms protective coverings and linings for all body surfaces, cavities, and organs, also making up glands, functioning in absorption, secretion, filtration, protection, and sensation. Characterized by tightly packed cells with little space between them, it has a free surface and attaches to underlying connective tissue via a basement membrane, lacking its own blood vessels but receiving nutrients via diffusion. Tissues are classified by cell shape (squamous, cuboidal, columnar) and layers (simple, stratified, pseudostratified). 

Key Characteristics
  • Covering/Lining: Forms skin (epidermis) and lines internal structures like the digestive tract, blood vessels, and respiratory system.
  • Cellularity: Cells are tightly packed with minimal extracellular matrix.
  • Polarity: Has a free (apical) surface and a basal surface attached to the basement membrane.
  • Avascularity: No direct blood supply; relies on diffusion from underlying connective tissue.
  • Regeneration: High capacity for cell replacement. 
Functions
  • Protection: Forms a barrier against injury, pathogens, and dehydration (e.g., skin).
  • Absorption: Absorbs nutrients (intestines) or water (kidneys).
  • Secretion: Produces mucus, hormones, and enzymes (glands, stomach lining).
  • Filtration: Filters blood (kidneys).
  • Sensation: Contains sensory receptors for touch, pain, and temperature. 
Types (by Shape & Layers)
  • Simple (Single Layer):
    • Squamous: Flat, thin cells for diffusion/filtration (e.g., air sacs, blood vessels).
    • Cuboidal: Cube-shaped cells for secretion/absorption (e.g., kidney tubules, glands).
    • Columnar: Tall cells for absorption/secretion (e.g., stomach, intestines).
    • Pseudostratified Columnar: Appears layered but isn't; ciliated cells line respiratory tract.
  • Stratified (Multiple Layers):
    • Stratified Squamous: Multiple layers of flat cells for protection (e.g., skin, mouth).
    • Stratified Cuboidal/Columnar: Rare, found in ducts of large glands.
  • Transitional: Stretches and recoils (e.g., urinary bladder). 

Comments

Post a Comment

Popular posts from this blog

                                       My degree, My Country, My World                   I have followed my degree on Biological sciences.Biological science is one of the most important subject in the world today.Biology encompasses everything from the molecular study of life process,right up to the study of animal and plant communities. There are so many importance from a biology degree to the country.They are in bio technology,in forensic science,in government and policy,in economics and science and publishing and communication. From a biology degree the major contribution to the world is we can solution for the major problems that the people suffer.The main suffering problems are the water problem and food production.and also from a biological degree we can find the solutions for the large scale concerns that may affect anyone from d...
Read more
MY DEGREE ,MY COUNTRY, MY WORLD Degree is a any justification for the job market but it is not sufficient. Because the new world is very advanced and competitive. So if we need a good job, we may have load of qualifications. So my degree is BSc. General in Applied science (Biological Science). My target is finding a good job. But some people prefer the academic field so we can work any field from this degree. Because i learn three subjects. My majors are Chemistry , Zoology, and   Botany. In chemistry we learn Organic chemistry, Inorganic chemistry , Physical chemistry and their practical knowledge. But our country is a developing country so our country   have very few industries. Even though we have   low job market in chemistry , some good jobs are available. In zoology and botany we learn Economic botany, Postharvest technology in plant products, Food microbiology, Horticulture and   landscaping, and Molecular Biology ...etc. So these causes directly target th...
Read more
Image
                        My Degree, My Country, My World                  I have followed my degree on Information Communication Technology in Applied Sciences, Rajarata University of Srilanka.ICT is most important and valuable degree program in today.In modern society ICT is ever-present, with over three billion people having access to the Internet.Especially in developing countries, has led ICT to become a keystone of everyday life.ICT is more important to every one today.Lets talk about it.                  Today ICT is of first rate in education systems.ICT has an important prominent role in knowledge due to its changeable ability and its capability to making relationship among students.It has created thousands of new job opportunities.IT industry is the second largest fields that gain foreign exchange.IT field is interrelated with ...
Read more