Tissues

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Tissues
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Terms to know

• Tissue
• A group of similar cells with a common embryonic
  origin.
• Histology
• The science that deals with the study of tissues.
• Pathologist
• A scientist who specializes in the diagnosis and
  examination of cells and tissues.

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The 4 Basic Tissue Types

• Epithelial tissue
• Connective tissue
• Muscular tissue
• Nervous tissue

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Epithelial tissue

• Covers body surfaces, lines body cavities, hollow
  organs and forms glands.
• Consists of closely packed cells with little
  extracellular material between them, arranged in
  single or multiple sheets.
• Has an apical (free) surface, that is open to a
  body cavity.
• Has lateral surfaces, that face cells on either
  side.
• Has a basal (deepest layer) surface, that is
  attached to a basement membrane that helps to
  bind and support the epithelium.
• Is avascular ( a- without, vascular blood ) and
  lacks blood vessels. Materials are exchanged via
  diffusion.
• Is subject to wear and tear and injury, so it has
  a high capacity for renewal by cell division.

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Two Types of Epithelial Tissue

• Lining and Covering
• Epithelial
• Forms the outer of the skin.
• Forms the outer covering of some internal organs.
• Lines body cavities, blood vessels.
• Interiors of several organ systems.
• Parts of the sense organs.

• Glandular Epithelial
• Forms the secreting portion of the glands, such
  as sweat glands.

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4 Basic Shapes of Covering and Lining Epithelium

• Squamous ( flat) Flat and attach to each other
  like tiles. Thinness allows for rapid passage of
  substances through them. (skin)

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2) Cuboidal cells get their name from their
shape. They may have microvilli on their free
surface. Function Secretion (sweat, mucus and
enzymes) and Absorption (digested food in
intestines).
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3) Columnar cells are taller than wide. They
protect underlying tissue and aid in secretion
and absorption. ( gallbladder)
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4) Transitional cells are able to change in
shape from cuboidal to flat as organs stretch
(distend) to a larger size and then collapse.This
prevents the organs from rupturing. Ex. Bladder.
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Papanicolaou test Pap smear

• A test to detect early changes in the cells of
  the female reproductive system. Sloughed off
  apical cells from the epithelium of the cervix
  and vagina are collected and microscopically
  examined. The Pap test in recommended annually
  for all women to aid in the detection of
  precancerous or cancerous cells.

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2 Types of Glandular Epithelium

• Endocrine glands
• Exocrine glands

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The function of glandular epithelium is
secretion. A gland may consist of one or more
groups of highly specialized epithelial cells
that secrete substances into ducts, onto a
surface or into the blood. Glands may be either
endocrine or exocrine.
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Endocrine glands(endo- within/ -crine
secretion)

• Secrete hormones.
• Diffuse directly into bloodstream.
• Regulate metabolic and physiological activities.
• Ex. Pituitary gland

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Exocrine glands( exo- outside)

• Secrete product into ducts that empty onto an
  apical (free) surface.
• Include mucus, perspiration, earwax, milk,
  saliva, oil and digestive enzymes.
• Picture 1 colon 2 active mammary gland

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Connective Tissue
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Features of connective tissue

• Consists of cells and a matrix
• Does not occur on free surfaces
• Has a nerve supply and is highly vascular (rich
  in blood)
• Vascular exceptions cartilage tendons

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Connective tissue cellsFibroblasts

• Aid in healing wounds.

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Macrophages

• macro- large / -phages eaters
• Develop from a type of white blood cell, are
  involved in the defense of body tissues.

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Mast Cells

• Produce histamine during an allergic reaction.
• Increase blood flow to injured areas.

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Adipocytes

• Also called fat cells, they contain large amounts
  of fats and oils. Fat cells are found under the
  skin and around organs.
• As a person gains weight the fat cells grow in
  size, not amount.
• Men carry fat in chest, abdomen and buttocks
  (apple)
• Female carry hips, breasts, waist, buttocks
  (pear)

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Liposuction
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Six types of connective tissue

• Loose connective tissue
• Dense connective tissue
• Cartilage
• Bone tissue
• Blood tissue
• Lymph

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Loose Connective Tissue

• Areolar Connective Tissue
• Adipose Connective Tissue
• Reticular Connective Tissue

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Dense Connective Tissue

• Provides strong attachment sites between
  structures (tendon) and strength.
• Makes up tendons, ligaments and deeper parts of
  the dermis of the skin, pericardium of the heart.
• Contains a liquid matrix called blood plasma, a
  straw colored liquid that is 90 water.

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Cartilage

• Consists of collagen and elastic fibers.
• Three types of cartilage include hyaline,
  elastic and fibrocartilage.
• Function Gives support and maintains shape.
• Location epiglottis, external ear, auditory
  tubes.

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Bone tissue

• Bone tissue can be either compact or spongy.
• Bone tissue makes up the various bones in the
  body.
• Function support, protection, storage, blood
  forming tissue

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Blood tissue (blood)

• Blood makes up 6-10 of body weight.
• Contains red blood cells (RBCs) that transport
  oxygen.
• White blood cells (WBCs) that are involved in
  phagocytosis, immunity and allergic reaction.
• Platelets which aid in blood clotting.

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Lymph

• Lymph is a fluid that flows in the lymphatic
  vessels. It is a connective tissue that consists
  of several types of cells in a clear fluid.

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Muscle Tissue
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General characteristics

• There are 3 types of muscle tissue smooth,
  skeletal and cardiac.
• Muscle tissue consists of elongated cells called
  muscle fibers, that generate force.
• Muscle tissues produce motion, maintain posture
  and generate heat.

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Skeletal muscle

• Usually attached to bones of the skeleton.
• Striated (alternating dark and light bands) and
  voluntary (can be made to relax or contract by
  conscious control.)
• A single skeletal muscle fiber can be 30-40 cm
  long.

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Cardiac Muscle

• Forms the bulk of the heart wall.
• It is striated and involuntary (cannot be
  consciously controlled).
• Fibers are attached at intercalated discs.
• Function Pumps blood throughout the body.

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Smooth Muscle

• Composes the walls of hollow internal structures
  (vessels, stomach, lungs).
• Its contractions help to constrict blood
  vessels, break down and move food along GI tract,
  eliminate wastes.
• Smooth muscles are involuntary and nonstriated.
• Pictures smooth muscle fiber,colon cross section

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Nervous Tissue

• Consists of 2 principle cells neurons and
  neuroglia.
• Neurons (nerve cells) are sensitive to various
  stimuli.
• Location nervous system
• Function Exhibits sensitivity to various types
  of stimuli, converts stimuli into nerve impulses
  and sends to muscle fibers, glands and other
  neurons.

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Structure of a Neuron
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Types of malignant cancer

• Picture 1 breast cancer
• Picture 2 lung cancer
• Picture 3 basal cell carcinoma of nose