Tissues Flashcards
- where rapid diffusion is priority
–kidney, lungs
–lines body cavities
single squamous epithelia
- common in ducts of glands (salivary glands, pancreas)
- forms walls of kidney tubules
- functions in secretion and absorption
simple cuboidal epithelia
• Some have microvilli and others cilia
• Often includes mucus-secreting cells = Goblet Cells
• Functions in secretion and absorption of mucus, enzymes, etc.
• Location:
– Lines the entire Digestive tract, Bronchi, Uterine Tubes
simple columnar epithelia
• Functions in secretion and
movement of mucus
• Location: Upper
Respiratory Tract
- many have cilia
pseudo stratified columnar epithelia
Most widespread of stratified epithelia
• Free surface is squamous, w deeper cuboidal or columnar layers
• Protective Covering in areas of high wear and tear (example: Skin)
• Keratinized cells found in skin
• Non-keratinized cells are found in moist linings (Mouth; Esophagus)
stratified squamous epithelia
• Where: sweat and salivary gland ducts
• What: secretion, absorption
stratified cuboidal epithelia
• Where: mammary gland ducts, larynx
• What: secretion
stratified columnar epithelia
• Forms lining of hollow urinary organs
• Found in bladder, ureters, and urethra
• Cube-shaped when organ/tube not stretched
• Squamous when organ/tube is stretched by fluid
transitional epithelia
• Ductless since secretions diffuse into blood vessels
• All secretions are Hormones
endocrine glands
• Secretions empty through ducts onto body surfaces (skin) or
into body cavities
• Mucous, Sweat, Oil, Salivary
• Can be:
– Unicellular: Goblet Cells (mucus) => Intestine and Respiratory Tract
– Multicellular: Most Exocrine Glands
- Classified by: Structure and Mode of Secretion
exocrine glands
gland where vesicles empty their contents into the duct through exocytosis, like sweat glands
merocrine gland
gland where a portion of the cell containing secretory products is pinched off the cell, like mammary glands
apocrine gland
gland where entire cells are shed off by the gland and are secreted, like sebaceous glands
holocrine glands
– Most widely distributed connective tissue
– Wraps and cushions organs
– Helps hold internal organs together and in their proper
positions
• E.g. Attaches skin to underlying tissues
– Extracellular Matrix:
• produced by cells called FIBROBLASTS
• Clear, Colorless, Viscous
• Fewer Fibers; More Ground Substance
– Can act as water reservoir by holding more fluid
– Body cells obtain nutrients from and release waste into
this “tissue fluid”
– During inflammation it soaks up excess fluid (causes
edema)
loose areolar connective tissue
• Highly vascularized
• Adipocytes cells in extracellular matrix
– Contain large lipid deposits
• Functions
– Insulates the body
– Protects some organs (kidneys, eyeballs)
– Serves as a site of energy storage
• Locations:
– Under the skin
– Around kidneys
– Hips
– Breasts
adipose connective tissue (fat)
• Like areolar tissue but w Reticular Fibers (instead of
collagen and elastin fibers)
• Forms the cobweb-like stroma of the spleen, lymph
nodes, and bone marrow
• Holds blood cells in place in these organs
loose reticular connective tissue
• More Fibers; Less Ground Substance
• Main matrix element Collagen Fibers (stacked on top of
each other in orderly arrangement)
• Main cell type Fibroblasts
• Poor Blood Supply
• Locations
• Tendons—muscle to bone
• Ligaments—bone to bone at joints
dense regular connective tissue
• Main matrix element Collagen Fibers (random
arrangement)
• Main cell type Fibroblasts
• Locations: Dermis of Skin, Scars
dense irregular connective tissue
• Found in very elastic ligaments
– Example: Ligaments connecting adjacent vertebrae
• Also found in walls of many large arteries
– Arteries need to stretch when blood enters and recoil to push
blood out
elastic connective tissue
• Most Common type of cartilage
• Composed of:
– Chondrocytes in lacunae
– Abundant collagen fibers in proteoglycan matrix
• Found: where strong support is needed with some
flexibility
• Locations
– Nose tip
– Trachea/Bronchi
– Rib cage
– End of long bones (movable joints)
– Most of fetal skeleton prior to birth
• Involved in growth that increases bone length
hyaline cartilage
– Elastic and Collagen fibers in proteoglycan matrix
– Similar to hyaline but with more elastic fibers
– Provides elasticity (soft plastic) (rigid but elastic)
– Location
• External Ear
• Epiglottis
elastic cartilage
– Thick Collagen fibers in proteoglycan matrix
– Slightly compressible (like soles of good shoes) and tough
– Most collagen fibers of any cartilage
– Location: Areas of pressure on joints (shock absorbers)
• Forms cushion-like discs between vertebrae
Intervertebral Disks
• Knee joints
fibrocartilage
– Strong but porous (to
store Bone Marrow)
– Found Inside bones
• Inside Heads of
Long Bones
• Inner layer of Flat
Bones
– Lattice network of
trabeculae with large
spaces between them
spongy (cancellous) bone
– Dense w no visible spaces
– Found in Periphery (Outer) portion of all bones
– Stores Calcium
– Arranged in concentric layers around central canals
compact bone
