BELLWORK

TISSUES
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Tissues are made up of cells
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Cells connect with one another via different junctions to form tissues
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Tight Junctions: cells join together VERY tightly
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Example: cells in the intestine
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Gap junctions: spaces or “gaps” between cells that allow the flow of molecules
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Example: calcium between cells
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Adhesion junctions: act like “staples” to hold the cells together in the tissue
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Example: skin cells

TISSUES
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There are 4 primary Tissue Types
1.
2.
3.
4.
Epithelium: covers the body surfaces, lines body cavities, and forms glands
Connective: protects and supports the body
Muscular: generates physical force needed for body movements
Nervous: detects changes inside and outside the body, coordinates body activities

EPITHELIAL TISSUE
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Divided into 2 types
1.
Covering & Lining Epithelium:
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Covers the surface outside of the body and lines internal organs
2.
Glandular Epithlium:
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Makes up the secreting portion of glands (sweat glands)
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Secretes hormones or other products
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Functions
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Protection, Absorption, Filtration and Secretion

EPITHELIAL TISSUE
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Characteristics
1.
Epithelial cells are packed closely together to form continuous sheets
2.
3.
4.
Epithelial cells have an apical surface and a basal surface
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Apical: most superficial layer of cells
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Basal: deepest layer of cells; between the epithelium and the underlying connective tissue
Epithelial cells are avascular — they lack blood vessels
Can regenerate easily – cells are replaced quickly

EPITHELIAL TISSUE
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Covering and Lining Epithelium
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Classified according to the number of layers and the shape of the cells
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Number of layers
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Simple: one layer
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Stratified: more than one layer
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Pseudostratified: looks like many layers but it’s only one layer

EPITHELIAL TISSUE
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Covering and Lining Epithelium
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Shape of cells
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Squamous: flattened
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Cuboidal: cube - shaped
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Columnar: column-like
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Combining number of layers and cell shape creates the different types of covering and lining epithelium

1.
2.
3.
4.
5.
6.
7.
What are tissues made off
Cube-liked shaped cells
Type of tissue which supports and protects the body
Junctions which hold cells very close together
Tissue which detects chages inside and outside the body
Looks like multiple layers but is only one layer of cells
The 4 characteristics of epithelial tissue

EPITHELIAL TISSUE
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Simple Epithelium
1.
Simple Squamous
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Single layer of flat cells
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Found in the air sacs of lungs and lining of the heart and blood vessels
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Allow materials to pass through by diffusion and filtration
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Secretes lubricating substances

EPITHELIAL TISSUE
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Simple Epithelium
2.
Simple Cuboidal
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Single layer of flat cube-shaped cells
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Found in the ducts and secretory portions of small glands and in kidney tubules
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Secretes and absorbs

EPITHELIAL TISSUE
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Simple Epithelium
3.
Simple Columnar
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Single layer of tall/column like cells
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Ciliated Tissues: found in bronchi, uterine tubes and uterus
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Smooth(unciliated): found in the digestive tract, bladder
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Absorbs and secretes mucous and enzymes

EPITHELIAL TISSUE
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Simple Epithelium
4.
Pseudostratified
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Single layer of cells, some are shorter than others
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Often looks like a double layer
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Lines the trachea and the upper respiratory tract
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Secretes mucus, and moves mucus

EPITHELIAL TISSUE
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Stratified Epithelium
1.
Stratified squamous
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Multiple layers of flat squamous cells
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Lines the esophagus, mouth and vagina
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Protects against abrasion

EPITHELIAL TISSUE
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Stratified Epithelium
2.
3.
Stratified cuboidal
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Rare
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Function is mainly protection, secretion and absorption
Stratified columnar
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Rare
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Function is protection and secretion

EPITHELIAL TISSUE
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Stratified Epithelium
4.
Transitional epithelium
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Shape of cells depends upon the amount of stretching
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Lines the bladder, urethra, and the ureters
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Allows the urinary organs to stretch and expand

EPITHELIAL TISSUE
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Glandular Epithelium
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Function is to secrete enzymes, hormones, oil, sweat, earwax, saliva and mucus
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Two major glandular epithelium gland types
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Endocrine gland: secretes hormones directly into the bloodstream
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Example: thyroid gland secretes the hormone thyroxin into the bloodstream and is distributed throughout the body raising metabolism
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Exocrine gland: secretes their substances into tubes which carry the secretions to the epithelial surface
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Example: sweat glands, saliva, mammary glands

EPITHELIAL TISSUE

EPITHELIAL TISSUE
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You’ll watch a review video and answer the questions you’ll find at the end of your notetaker
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These will be for a grade, if you don’t answer the questions because the video is to fast just pay attention, you’ll have time after the video to answer the questions