Ned Mejia Simulator

• TISSUES

  • It is a group of cells having similar structure and function.
  • The study of tissue is called Histology.
• • Cavity is the fluid filled space inside the body.
• Epithelial tissues can be found in different areas such as the body coverings, body linings, and the glandular tissue.
• NUMBER OF CELL LAYERS

  • Simple - one layer
  • Stratified - more than one layer
• SHAPE OF CELLS

  • Squamous - flattened
  • Cuboidal - cube shaped
  • Columnar - column like
• SIMPLE CUBOIDAL

  • It is for secretion.
  • They are a single layer of cube-like cells.
  • It is common in glands and their ducts.
  • It forms walls of kidney tubules.
  • It covers the ovaries.
• SIMPLE COLUMNAR

  • They are brick-shaped cells.
  • It is for secretion and active absorption.
  • A single layer of tall cells.
  • It often includes goblet cells, which produce mucus.
  • A mucus is a viscous fluid composed primarily of highly glycosylated proteins called mucins.
  • It lines the digestive tract.
• SIMPLE SQUAMOUS

  • They are plate-like cells.
  • It is for the exchange of material through diffusion.
  • A single layer of flat cells.
  • It usually forms membranes such as lines body cavities and lines lungs and capillaries.
• STRATIFIED SQUAMOUS

  • It lines the esophagus, mouth, and vagina.
  • It protects against abrasion.
• STRATIFIED CUBOIDAL

  • It has multiple layers of cuboidal cells.
  • It lines the ducts of the sweat glands (Sudoriferous), salivary glands, and mammary glands.
  • It is found in ovarian follicles and seminiferous tubules of the testes.
  • Its main function is to provide a robust protective layer for underlying tissues.
• STRATIFIED COLUMNAR

  • It has multiple layers of columnar cells.
  • It is found in the conjunctiva of the eye, in parts of the pharynx, anus, uterus, and the male urethra and vas deferens.
  • The conjunctiva lines the inside of the eyelids and covers the sclera (the white of the eye).
• PSEUDOSTRATIFIED COLUMNAR

  • They are a single layer of cells.
  • It is for the lining of the respiratory tract; that is usually lined with cilia (i.e., type of cell modification that sweeps the mucus).
  • Single layer, but some cells are shorter than others.
  • It often looks like a double cell layer.
  • It is sometimes ciliated, such as in the respiratory tract
  • It may function in absorption or secretion.
  • It may just look stacked because of varying height.
• CONNECTIVE TISSUE

  • It connects and joins the different parts of the body together. 
• • The cells of the connective tissue are loosely packed and the space between the cells are filled with a jelly like matrix (extracellular matrix).
• • Blood - It is made up of plasma (liquid extracellular matrix).
• Erythrocytes that carry oxygen (RBC), leukocytes for defense (WBC), and platelets (thrombocytes) for blood clotting.
• Bone - hard and strong tissue
• It mineralizes connective tissue made by bone-forming cells called osteoblasts which deposit collagen.
• Osteocytes is the alternative name for adult bone cells or mature bone cells.
• • Lacuna is a small space containing osteocytes.
• The Haversian canal contains small blood vessels responsible for the blood supply to osteocytes (individual bone cells).
• Cartilage - It is characterized by collagenous fibers embedded in chondroitin sulfate.
• • Chondrocytes are the cells that secrete collagen and chondroitin sulfate.
• • Chondroitin Sulfate is an important structural component of cartilage and provides much of its resistance to compression.
• Ligaments - They are flexible tissues which join bones together and help in movements.
• Tendons - They are fibrous tissues which join muscles to bones and help in movements.
• AREOLAR TISSUE

  • It fills the space between skin and muscles, inside the organs, around blood vessels etc.
  • It helps to repair the tissues.
• ADIPOSE TISSUE

  • It is found below the skin and between internal organs.
  • It contains fats and helps to store fats.
  • Adipocytes are fat cells.
• NERVOUS TISSUE

  • These tissues are composed of nerve cells called neurons and glial cells that function as support cells.
• • The dendrite is the part of the neuron that receives impulses from other neurons.
  • Axon is the part where the impulse is transmitted to other neurons.
• THREE TYPES

  APICAL MERISTEMATIC TISSUES

  • These are present in the tips of stems and roots.
  • They help in the growth of stems and roots.

  LATERAL MERISTEMATIC TISSUES

  • These are present in the sides of stems and roots.
  • They help to increase the girth of the stems and roots.

  INTERCALARY MERISTEMATIC TISSUES

  • These are present at the base of leaves and internodes and help in the growth of those parts.
• PERMANENT TISSUE

  • These are formed from meristematic tissues.
  • They do not divide and have permanent shape and size.
  • They differentiate into different types of permanent tissues.
  • Two main types:
  • Simple Permanent Tissues
  • Complex Permanent Tissues
• 1. SIMPLE PERMANENT TISSUES

  • These are made up of one type of cell.
  • It has three types called Parenchyma, Collenchyma, and Sclerenchyma.
• PARENCHYMA

  • Loosely packed thin walled cells having more intercellular spaces.
  • It contains chloroplast and prepares food by photosynthesis.
  • Roots and stems store water and minerals.
• COLLENCHYMA

  • It is less intercellular spaces and thicker at the corners.
  • It gives flexibility and allows easy bending of different parts like stem, leaf, etc.
  • It gives mechanical support to the plant.
• SCLERENCHYMA

  • It consists of long, narrow, dead thick walled cells.
  • Cell walls contain lignin - A chemical substance which acts like cement and hardens them.
• COMPLEX PERMANENT TISSUES

  • These are made up of more than one type of cells.
  • It has two types called Xylem and Phloem.
• XYLEM

  • It consists of tracheids, vessels, xylem parenchyma, and xylem fibers.
  • Tracheids and vessels help to transport water and minerals from roots to all parts of the plant.
• PHLOEM

  • It consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.
  • The sieve tubes and companion cells transport food from leaves to all parts of the plant.
• • Cellular modifications are commonly found in eukaryotic cells, where there is a need for cell specialization.