Plant Tissues Essay Sample
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- Word count: 990
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- Category: anatomy
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Introduction of TOPIC
1. Meristematic Tissue.
A. Apical Meristems
B. Lateral Meristems
2. Permanent Tissue
A. Dermal (Surface Tissue)
B. Fundamental Tissue (Ground Tissue)
C. Vascular Tissue
Composed of immature cells and are regions of active cell division. small, thin walls and rich in cytoplasm. Found in the growing tips of the roots and stem. A. Apical Meristems
* Responsible for increase in length of the plant body.Found on root tips and apical buds B. Lateral Meristems
* Responsible for increase in girth or diameter
* Ex: Cambium present in woody plants and produce the cork
A. Dermal (Surface Tissue)
* Forms the protective outer covering of the plant body A.1. Epidermis
* Produce cutin to protect plants against loss of water * Produce root hairs for absorption of water and minerals
* Replaces the epidermis
* Constitutes the corky outer bark of old trees.
B. Fundamental (Ground Tissue)
* Used in the production and storage of food and in the support of plant. B.1. Parenchyma
* Parenchyma on leaves function for photosynthesis * Mechanical strength by maintaining turgidity and also store waste products. B.2. Collenchyma
* Support of stems and adapt themselves to the rapid elongation of leaves. B.3. Sclerenchyma
* Provides elasticity, flexibility, and rigidity to the plant body forming support.
C. Vascular Tissue
C.1. Xylem Primarily functions for the transport of water and dissolved substances upward in the plant body.
C.2. Phloem Primary functions in the transport of organic materials such as carbohydrates and amino acids.
Developed from the primary germ layers of the embryo:
Ectoderm Mesoderm Endoderm There are 4 types of tissues: Epithelial tissue , Connective tissue ,Muscular tissue, Nervous tissue Classification of Epithelial Tissue based on Shape and Arrangement of Cells Simple squamous –found in the lens of the eye and inner ear Stratified squamous – forms the external layer of the skin and lines the mouth and pharynx. Cuboidal – mostly found lining small ducts and tubules of the kidney and the glands Simple columnar – found in the trachea, bronchi, digestive tract and secrete fluids and absorb digestive food. A. Connective Tissue Proper Very variable but intercellular m
atrix always contains numerous fibers. 2 Types of Connective Tissue Proper
Made up of highly elastic fibers with few scattered thin collagen fibers. This tissue fills the space between organs and serves as packing materials surrounding the elements of other tissues This binds muscle cells together and binds skin to underlying tissues Ex. Adipose tissue, areolar tissue 2. Dense Connective Tissue
Made up of thick collagen fibers and dark, compressed cells between the fiber bundles. Functions: (1) for flexibility and support, (2) shock absorption and (3) reduction of friction.Ex. Tendon, ligament, urinary tract and collagen B. Cartilage
Made up of cells known as chondrocytes found in cavities .Provides smooth
surfaces and maintain the shape of the area.
Types of Cartilage
1. Hyaline cartilage –nose, larynx, trachea, bronchi, ends of ribs and surfaces of bones. 2. Elastic cartilage – yellow color, greater flexibility and elasticity and found in the external ear, Eustachian tube and epiglottis 3. Fibro cartilage – resembles a tendon but not covered by perichondrium C. Bone (Osseous tissue)
Has hard, relatively rigid matrix which contains numerous collagen fibers and a surprising amount of water, impregnated with mineral salts such as calcium carbonate and calcium phosphate. Bone is a living tissue with cells called osteocyte and masked collagenous fibers embedded in a matrix containing ostein. Covered with fibrous membrane –periosteum Lines the bone marrow cavity- endosteum Functions: (1) support; (2) protection; (3) assisting for movement and (4) storage of minerals D. Blood (Vascular Tissue) Consists of cells, matrix and fibers 3 Components of Blood
1. Erythrocyte (RBC) small, concave, disc-shaped cells that lack nuclei during maturation in mammals Formed in the bone marrow They arise from normally nucleated, rapidly dividing connective tissue cells of the bone marrow Contains hemoglobin 2. Leukocyte (WBC) Bigger than erythrocyte and have large, often irregularly shaped nuclei Defenses against disease and infection Act as phagocytes, engulfing and destroying bacteria and remnants of damaged tissue cells Produce powerful enzyme 3.Lymphocytes –specialized cells that play a central role in immune reactions by producing antibodies.
III. MUSCLE TISSUE
Function: responsible for movement in higher animals, heat production and maintenance of posture.
Types of Muscle Tissue
a. Striated or Voluntary Muscle (Skeletal Muscle) Has cross-striations (A-I bands) and can be controlled at will Consists of myofibrils which contains actomyosin.Sarcomere-the functional/structural unit of muscle contraction b. Smooth or Involuntary Muscle (Visceral Muscle) Spindle-shaped cells which are thickened at the middle but tapered towards ends. Without striation and responsible for involuntary movements of internal organs c. Cardiac Muscle Striated and branched muscle fibers Found exclusively in the heart (myocardium) and is involuntary in movement. IV. NERVOUS TISSUE Highly specialized for the conduction of nerve impulses. a. Nervous Tissue Proper Has specialized conducting cell called neuron, linked together to form pathways. b. Interstitial Tissue (Neuroglia) Supports the neuron
1. Cell body (soma/cyton)
* Enclosed by a membrane, with nucleus, cytoplasm and cellular organelles.
* Produces proteins and energy required for the function of the neuron.
* Numerous extensions that is short and branched
* receive signals from sensory receptors
* Connect with other neurons to collect stimuli and pass these on to the cell body
* Projections from the cell body that is long and thin
* conducts nerve impulses
* Any long axon is also called a nerve fiber
* Covered by myelin sheath
4. Terminal Branches/ Synaptic Terminals
* Attached to receptors of the body