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4 Types of Tissues
- -Epithelial
- -Connective
- -Muscle
- -Nervous
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3 Germ Layers
- -Endoderm
- -Mesoderm
- -Ectoderm
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Epithelial Tissue
- -Covers surfaces
- -Little extracellular material
- -Basement Membrane
- -Avascular (no blood supply)
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Epithelial Cells
- -Apical surface (free surface)
- -Lateral surface (attached to other cells)
- -Basal surface (attached to basment membrane)
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Functions of Epithelial Tissue
- -Protect underlying structures
- -Acting as barriers
- -Permitting the passage of substances
- -Secreting substances
- -Absorbing substances
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Epithelial Tissue Classified by:
- -Number of cell layers
- -Cell shape
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Simple epithelium function
- -Diffusion
- -Secretion
- -Absorption
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Statified epithelium function
protection
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Squamous epithelium function
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Cubodial or Columnar cells containing cellular organelles function
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Desmosomes
mechanically bind cells together
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hemidesmosomes
mechanically bind cells to the basement membrane
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Gap junctions allow...
intercellular communication
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mesothelium
simple squamous epithelium, lines body cavity, thoracic
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Endocrine Glands
- -do not have ducts
- -secrete hormones directly into the blood
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Exocrine Glands
-secretions are released onto a surface or into a cavity.
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merocrine
no loss of cellular material (sweat glands)
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apocrine
- -part of cell pinches off
- -shed of apical surface
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Holocrine
-entire cell is shed (sebaceous glands)
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Connective Tissue Funcitons
- -Enclosing and Separating
- -Connecting Tissues to one another
- -Supporting and moving
- -Storing
- -Cushioning
- -Transporting
- -Protecting
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Blast
germ, an immature cell, forms the matrix
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Clast
cells break it down
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Extracellular matrix contains
- -Protein fibers
- -Ground substance
- -Fluid
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Types of Protein fibers
- -Collagen fibers=flexible but resist stretching
- -Reticular fibers=form a fiber network
- -Elastic fibers= recoil
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Muscle Cell
muscle fibers
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Muscle Tissue Function
Contract, or shorten, making movement possible.
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Nervous tissue specialized to...
conduct action potentials (electrical signals)
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Neurons
the functional unit
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Neurogila
support the neurons
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mucous membranes
line cavities that open to the outside of the body
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Serous membranes
line trunk cavities that do not open to the outside of the body
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synovial membranes
line freely movable joints
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Skeletal muscle
- -striated
- -voluntary
- -multinucleated
- -elongated
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Cardiac Muscle
- -involuntary
- -straited
- -intecalated discs
- -uninucleated
- -branch shaped
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Smooth Muscle
- -involuntary
- -nonstriated
- -uninucleated
- -spindle shaped
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Function of Skin
- -Protection
- -Sensation
- -Temperature regulation
- -Vitamin D production
- -Excretion of small amounts of waste products
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Keratinocytes
- -most abundant cell type
- -produce the fibrous protein keratin
- -gives sking its protective properties
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Melanocytes
- -produce the brown pigment melanin
- -found in the deepest layers of the epidermis (granulosum)
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Langerhans' cells
- -epidermal macrophages
- -help activate the immune system
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Merkel Cells
-touch receptors in association with sensory nerve endings
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Thick skin composed of
Five epithelial strata
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Thin skin is missing
stratum lucidum
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hair is found only in
thin skin
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2 layers of dermis
papillary and reticular
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