BIO200 INTRODUCTION TO TISSUES, CLASIFICATION OF LIVING THINGS & ECOLOGY TISSUES
BIO200INTRODUCTION TO TISSUES,
CLASIFICATION OF LIVING THINGS & ECOLOGY
TISSUES
ANIMAL TISSUES
RELECTION
DEFINITON OF TISSUE
• Groups of cells of similar appearance and a common function
• A group of closely associated, similar cells that carry out specific functions.
ANIMAL TISSUES
• 4 main categoriesi) epithelial tissueii) muscle tissueiii) connective tissueiv) nervous tissue
EPITHELIAL TISSUE
EPITHELIAL TISSUE
• Sheets of cells – covering the outside of the body and lines the organs and cavities within the body.
• Close packing of epithelial cells – involve in tight junction (function as a barrier against mechanical injury, pathogens and fluid loss) - example??
• Form active interfaces with the environment – epithelium lines the nasal passages
• Polarized – 2 different sides (apical & basal)• Apical surface – faces the lumen
cavity/outside of the organ- exposed to the fluid or air- often covered with specialized projections (e.g epithelial of small intestine – microvilli)
• Basal surface – attached to a basal lamina, a dense mat of extracellular matrix
• Separates the epithelium from the underlying tissue.
Figure 40.5ab
Apical surface
Basal surfaceBasal lamina
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Polarity of epithelia
• Types of epithelial cell shapes– Squamous (like floor tiles)– Cuboidal (like dice)– Columnar (like bricks standing on end)
• Type of epithelial tissue arrangement– Simple (single cell layer)– Stratified (multiple tiers of cells)– Pseudostratified (a single layer of cells
varying in height)
Simple squamous epithelium
• Simple squamous epithelium- thin and leaky- function in exchange of material by diffusion- Lines blood vessels and air sacs in the lungs (diffusion of nutrients and gasses is critical)
Simple squamous epithelium
Simple columnar and cuboidal
• Simple columnar and cuboidal- lines passageways- specialized for secretion and absorption- lines the intestines- secretes digestive juices and absorb nutrient
Simple cuboidal Simple columnar
• Stratified squamous epithelium- outer layer of skin- line passageways into the body- provides protection- regenerates rapidly by cell division near basal lamina. The new cells are pushed outward, replacing the cells that are sloughed off.- commonly found on surfaces subject to abrasion (outer skin, anus, vagina)
Stratified squamous epithelium
Stratified squamous
Pseudostratified ciliated columnar
• Pseudostratified ciliated columnar- lines passageways, protects underlying tissue- a mucous membrane that lines portions of respiratory tract
Pseudostratified ciliated columnar
MUSCLE TISSUE
Muscle Tissue
• Tissue responsible for nearly all types of body movement
• Consist of filaments containing the proteins actin and myosin
How many types of muscle tissue?
Types of muscle tissues
• 3 types of muscle tissue :- skeletal muscle- Cardiac muscle- Smooth muscle
Types of muscle tissue
Skeletal muscle
Skeletal muscle
• Attached to bones by tendons• Responsible for voluntary movements• Consists of bundles of long cells called
muscle fibers.• Also called striated muscle (the arrangement
of overlapping filament gives the cells a stripped appearance)
Skeletal muscle
Cardiac muscle
• Forms the contractile wall of the heart.striated like skeletal muscle, but
• Cardiac mus.- branched• End of cells – joined by intercalated disc
(relay signals from cell to cell during heartbeat, synchronize the heartbeat)
Cardiac muscle
Cardiac muscle
Cardiac muscle
Smooth muscle
• Named because lacks striations. Spindle-shaped cells lacking cross striations.
• Found in the walls of digestive tract, urinary bladder, arteries and other internal organ.
• Contract slowly thanskeletal muscle – but longer.
• Involuntary movement, such as churning of the stomach or construction of arteries.
Smooth muscle