Epithelia Tissue
Avascular; innervated |
Forms boundaries |
Polarity |
Specialized contacts |
Supported by
connective tissue |
Can regenerate |
Multicellular Exocrine Glands
Merocrine Gland |
Apocrine Gland |
Holocrine Gland |
Produce secretion, but gland is not damaged |
Bud secretions off through vesicles |
Secretions destroy cell |
Most common type; Secretes products as produced |
Only apex ruptures |
Accumulates product then ruptures |
Composed of a duct and secretory unit; usually surrounded by supported connective tissue
Unicellular Exocrine Glands
Mucous cells and Goblet cells |
Found in epithelial lining of intestinal and respiratory tracts |
All produce mucin (dissolves in water to form mucus) |
Glands
Endocrine Glands |
Exocrine Glands |
*Ductless; secretions not released
into a duct |
Secretions released onto body surfaces or cavities |
Secretes hormones by excocytosis |
More numerous than endocrine |
Hormones travel through blood or lymph to target organ |
Secrets into ducts |
Glandular Epithelia
One or more cells that makes and secretes a fluid called secretion |
Classified by site of product release and relative # of cells forming gland |
Transitional Epthelia
Forms lining of hollow urinary organs |
Basal layer is cuboidal or columnar |
Ability to change shape with stretch |
Apical cells vary in appearance |
Stratified Columnar Epithelia
Limited distribution in body |
Only apical layer is columnar |
FOUND IN: some glandular ducts; transition areas between other epithelia |
Stratified Cuboidal Epithelia
Very rare |
Found in some sweat and mammary glands |
Typically two cell layers thick |
Stratified Squamous Epithelia
Most widespread of stratified epithelia |
Free surface squamous, deeper layers cuboidal or columnar |
Located for wear and tear |
Farthest from basal layer (nutrients) less viable |
Forms epidermis of skin, moist linings of esophagus |
Pseudostratified Columnar Epithelium
Cells vary in height; some don't reach surface |
May contain mucus-secreting cells and bear cilia |
Secretes substances (mucus) & propulsion of mucus by cilia |
FOUND IN: ducts of large glands; trachea |
Simple Columnar Epithelium
Single layer of tall, closely packed cells |
Absorption; secretion of mucus, enzymes |
FOUND IN: most of digestive tract, excretory ducts, uterine tubes |
Simple Cuboidal Epithelia
Single layer of cells |
For secretion and absorption |
Forms walls of smallest ducts of glands |
FOUND IN: kidney tubules and ovary surface |
Simple Squamous
Cells flattened laterally |
Cytoplasm is sparse |
Function where rapid diffusion is priority |
Secretes lubricating substances in serosae |
FOUND IN: kidney; lungs; lining of heart; lymphatic vessels |
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Bone
aka osseous tissue
Supports and protects body structures
Stores fat and synthesizes blood cells in cavities
More collagen than cartilage
Has inorganic calcuim salts
Osteoblasts product matrix
Osteocytes maintain matrix
Osteons are structural units
Richly vascularized |
Cartilage DOES NOT turn into bone
Blood
Most atypical connective tissue--is a fluid
Red blood cells most common cell type
Also contains white blood cells and platelets
Fibers are soluble proteins that precipitate during blood clotting
Functions in transport |
Connective Tissue
Most abundant of primary tissues |
Has mesenchyme |
Binding and support |
Varying degrees of vascularity |
Protecting |
Has extracellular matrix |
Insulating |
Storing reserve fuel |
Transporting substances |
Types of Cartilage
Hyaline |
Elastic |
Fibrocartilage |
Amorphous but firm matrix |
Elastic fibers in matrix |
Matrix less firm than hyaline |
Supports and reinforces |
Maintains shape of structure |
Thick collagen fibers dominate |
Resilient cushion |
Allows great flexibility |
Absorbs compressive shock |
Resists compression |
Supports external ear |
Discs of knee joint |
Costal cartilage
of ribs |
Cartilage
Contains chondroblasts and chondrocytes
Tough yet flexible
Lacks nerve fibers
Up to 80% water so it can rebound after compression
Avascular so receives nutrients from membrane surrounding it (perichondruim) |
Elastic Connective Tissue
Some ligaments very elastic (ones connecting adjacent vertebrae) |
Allows recoil after stretching |
Found in walls of large arteries |
Dense Irregular Connective Tissue
Same elements but bundles of collagen are thicker and irregularly arranged |
Resists tension from many directions |
Provides structural strength |
Dense Regular Connective Tissue
Closely packed bundles of collagen fibers; runs parallel to direction of pull |
Fibroblasts manufacture fibers and ground substance |
Few Cells |
Poorly vascularized |
Reticular Connective Tissue
Resembles areolar but fibers are reticular fibers |
Fibroblasts called reticular cells |
Supports free blood cells in lymph nodes, spleen, and bone marrow |
Adipose Tissue
White Fat |
Brown Fat |
Cell is adipocyte |
Use lipid fuels to heat bloodstream |
Scanty matrix |
Does not use ATP |
Richly vascularized |
Found mosty in infants |
Shock absorption,
insulation,
energy storage |
Areolar Connective Tissue
Support and bind other tissues |
Most widely distributed |
Provides reservoir of water and salts |
Defend against infection |
Store nutrients as fat |
Has fibroblasts |
Loose arrangement of fibers |
When inflamed it soaks up fluid edema |
Connective Tissue Proper
Loose Connective Tissue |
Dense Connective Tissue |
Areolar |
Dense Regular |
Adipose |
Dense Irregular |
Reticular |
Elastic |
All connective tissue except bone, cartilage, and blood
Other Cell Types in Connective Tissue
Fat Cells store nutrients
White Blood Cells Tissue response to injury
Mast Cells Initiate local inflammatory response against foreign bodies
Macrophages Phagocytic cells that "eat" dead cells, microorganisms; immune system |
Cells in Connective Tissue
"Blast" cells are immature form; mitotically active; secrete ground substances and fibers
Fibroblasts in connective tissue proper
Chondroblasts in cartilage
Osteoblasts in bone
Hematopoietic stem cells in bone marrow
"Cyte" cells are mature form; maintain matrix
Chondrocytes in cartilage
Osteocytes in bone |
Connective Tissue Fibers
Collagen |
Elastic |
Reticular |
Strongest; most abundant |
Networks of elastin fibers |
Highly branched collagenous fibers |
Tough
provides
tensile strength |
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Muscle Tissue
Highly vascularized |
Responsible for most types of movement |
Skeletal Muscle
Found in skeletal muscle |
Voluntary movement |
Long, cylindrical, multinucleate cells; has striations |
Cardiac Muscle
Found in walls of heart |
Involuntary control |
Branching, striated, generally uninucleate cells |
Contains intercalated discs |
Smooth Muscle
Spindle-shaped cells with central nuclei |
No striations |
Cells arranged closely to form cheets |
Involuntary control; propels substances along passageway |
Found mostly in walls of hollow organs |
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Nervous Tissue
Main component of nervous system |
Transmit electrical signals from sensory receptors to effectors |
Neurons
Specialized nerve cells that generate and conduct nerve impulses |
Branching cells |
Located in brain, spinal cord, and nerves |
Neuroglia
Supporting cells that support, insulate, and protect neurons |
Covering and Lining Membranes
Cutaneous |
Mucous |
Serous |
Skin |
Mucosa indicates location; not composition |
Serosae found in ventral cavity |
Dry Membrane |
All called mucosae |
Parietal serosae line internal body cavity walls |
Keratinized strat. squamous attached to thick layer of connective tissue (dermis) |
Moist membrane bathed by secretions |
Visceral serosae cover internal organs |
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May secrete mucus |
Serous fluid between layers |
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Epithelial sheet
lies over layer
of connective
tissue called
lamina propria |
Moist membranes |
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Mesothelium rests on thin areolar connective tissue |
Composed of at least two primary tissue types
Epithelium bound to underlying connective tissue proper
Are simple organs
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