Term
| Characteristics of Epithelial Tissue |
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Definition
1) Cells tightly packed with little EC matrix. 2) Bottom layer of cells anchored to basement membrane. 3) Cells packed too closely for blood vessesl; must exchange material by diffusion to/from blood vessels in connective tissue. 4) Cells divide/heal quickly |
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Term
| Simple Squamous Epithelium |
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Definition
single layer of flat cells, may have a bulge for nuclei
function: rapid diffusion
location: capillaries and alveoli (sacs) in lungs |
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Term
| Simple Cuboidal Epithelium |
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Definition
single layer of cube-shaped cells with round nuclei
function: absorption and secretion
location: lining kidney tubules and the ducts of thyroid, pancreas and liver glands |
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Term
| Simple Columnar Epithelium |
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Definition
single layer of tall cells, elongated nuclei
apical surface has microvilli to increase rate of absorption and secretion
goblet cells secrete mucus
function: absorption and secretion
location: lining the digestive tract |
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Term
| Pseudostratified Columnar Epithelium |
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Definition
looks like layers, but all cells contact basement membrane
goblet cells secrete mucus
cilia on apical surface move mucus
function: move mucus and cells along the surface
location: lining respiratory tract and oviducts |
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Term
| Stratified Squamous Epithelium - Nonkeratinized |
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Definition
many layers, surface cells are squamous
cell division in basal (lower) layers pushes older cells pushed upward
outer layers are sloughed off
function: protection of underlying tissues
location: areas of wear and tear experiencing friction
mouth, esophagus, anus, vagina |
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Term
| Stratified Squamous Epithelium - Keratinized |
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Definition
many layers, surface cells are squamous
layers of dead cells on the surface contain lots of keratin protein, form waterproof layer
function: protection of underlying tissues
location: epidermis (outer part of skin) |
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Term
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Definition
changes appearance depending on tension on the organ
looks like many layers when relaxed, fewer layers when stretched
surface cells are rounded
function: allows stretching (number of layers seem to change when stretched)
location: lining urinary system, urinary bladder |
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Term
| Characteristics of connective tissue |
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Definition
cells typically spaced far apart and surrounded by a lot of extracellular matrix.
Functions include connecting organs, support, protection, movement, storage, transport. |
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Term
| Areolar connective tissue |
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Definition
loose connective tissue
fibroblasts surrounded by matrix with collagen and elastic fibers in random directions
Types of cells in areolar connective tissue:
fibroblasts – secrete the matrix
macrophages –attack and engulf foreign particles
leukocytes – white blood cells, react to foreign cells/substances
mast cells – secrete heparin to thin blood and histamine to dilate blood vessels
function: bind epithelia to other tissues, holds nerves and blood vessels for epithelia
location: under epithelia, small spaces between organs, membranes lining body cavities |
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Term
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Definition
specialized areolar connective tissue.
containes adipocytes (fat cells) filled with droplet of triglycerides.
function: stores triglycerides for energy, protects and insulates.
location: between muscles and skin, surrounding organs. |
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Term
| Dense regular connective tissue |
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Definition
parallel collagen fibers
function: provide great strength in one direction
location: tendons (connect muscle to bone), ligaments (connect bone to bone) |
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Term
| Dense irregular connective tissue |
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Definition
random bundles of collagen fibers
function: provide strength in all directions
location: dermis connecting outer layer of skin to muscle/connective tissue
around organs, bones, and cartilage |
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Term
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Definition
fibroblasts secrete densely packed bundles of collagen fibers.
little ground substance between fibers, fibroblasts flattened between bundles.
strong, but few blood vessels make it hard to heal. |
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Term
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Definition
Chondrocytes surrounded by secreted collagen fibers, chondroitin, and
rubbery-gel ground substance.
Ground substance is too stiff for cells for be embedded in it.
Chondrocytes are in cavities called lacunae.
Few blood vessels, materials exchange by slow diffusion through the stiff matrix.
Cells divide slowly and tissue heals slowly. |
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Term
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Definition
Most common, very smooth, can’t see collagen fibers between lacunae.
Function: provides shape and support, smooth movement.
Location: tip of nose, rings around trachea, articular cartilage on ends of bone. |
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Term
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Definition
More flexible, contains visible elastic fibers in the area between lacunae
Function: flexible and stretchy support
Location: earlobe, epiglottis |
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Term
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Definition
Very tough, visible collagen bundles embedded in the ground substance.
Function – absorbs shock.
Location: intervertebral disks, meniscus of knee joint. |
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Term
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Definition
Osteocytes in a hard matrix of collagen fibers, chondroitin, calcium salts.
Bone tissue is arranged in osteons.
Ostocytes secrete the matrix in layers (called lamellae) around a central canal.
Central canal contains blood vessels and nerves.
Osteocytes are in lacunae.
Connected to each other and central canal by tiny channels called canaliculi.
Provides access to blood supply, allows bone to heal.
Function: support, protection, calcium storage.
Location: external surface of all bones. |
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Term
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Definition
Blood cells suspended in fluid ground substance called plasma.
Types of blood cells:
erythrocytes – red blood cells, carry oxygen.
leukocytes – white blood cells, part of immune system to protect body.
platelets – cell fragments involved in blood clotting.
Function: transport cells and materials.
Location: inside blood vessels. |
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Term
| Characteristics of muscle tissue |
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Definition
Excitable cells that contract and produce force.
Excitable means that cells respond to stimuli with changes in membrane potential.
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Term
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Definition
Membrane potential is the difference in charge between outside and inside of cell
caused by difference in ion concentrations.
Na/K ATPase pumps 2 K+ into the cell and 3 Na+ out of the cell; K+ leaks out of the cell.
Cell has more + charges outside than inside;
the difference in charge is an electrical potential measured in volts.
Signal from a neuron opens ion channels in the muscle.
Ions moving into the cell change the membrane potential and trigger contraction. |
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Term
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Definition
Large cells with many nuclei called muscle fibers.
Striated – alternating light and dark bands
caused by alternating bands of myosin and actin that allow strong contraction.
Voluntary – we have conscious control over contraction and relaxation.
Location: attached to bones, esophagus, tongue, sphincters.
Function: body movement, speech, swallowing, control of bladder/bowels. |
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Term
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Definition
Long tapered cells (fusiform) with one nucleus.
Not Striated – contain actin and myosin, but not lined up the same way.
Involuntary – not under conscious control.
Location: iris of eye, hair follicles, visceral muscle in digestive, urinary, respiratory,
and circulatory systems.
Function: constriction of pupil, hairs standing on end, moving food, waste, and air though
the body, controlling dilation of blood vessels to regulate blood pressure. |
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Term
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Definition
Branched cells with one nucleus, joined by intercalated disks. Intercalated Disks Contain: adhering junctions to hold cells together despite force of contraction;
gap junctions for fast communication between cells so cells contract together.
Striated - visible, but less distinct than in skeletal muscle.
Involuntary – contains its own pacemaker that causes it to contract rhythmically.
Signals from nervous system may adjust the rate, but the heart beats on its own.
Location: heart
Function: pump blood |
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Term
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Definition
Types of cells in nervous tissue:
Neurons – excitable cells that detect stimuli and transmit information to other cells.
Soma – cell body of neuron containing nucleus.
Dendrites – processes that receive information and relay it to the soma.
Axon – long process that transmits information from the neuron to the next cell.
Neuroglia (glial) – cells that protect and support the neurons.
Location: brain, spinal cord, peripheral nerves
Function: communication between parts of the body, relaying info to and from the brain
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Term
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Definition
A cell or organ that synthesizes a substance (called the secretion) to be released.
Single cell glands like goblet cells.
Organs formed from invaginations in the epithelium.
Epithelial cells synthesize the secretion and connective tissue supports the gland. |
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Term
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Definition
Exocrine glands have ducts to the surface of the epithelium.
Release secretions onto a surface.
Examples: sweat glands, mammary glands, goblet cells. |
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Term
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Definition
Endocrine glands have lost their connection to the surface of the epithelium.
Do not have ducts.
Release secretions (hormones) into the blood and
allow communication between parts of the body.
Examples: pancreas, thyroid, pituitary glands. |
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Term
| Types of Exocrine Gland Secretions |
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Definition
Serous – produce watery secretions containing proteins, fats, salts, etc.
ex. sweat, milk, tears, digestive juices
Mucus – produce thick secretion containing a glycoprotein called mucin. Mucin absorbs water and becomes thick and sticky.
ex. goblet cells
Cytogenic – release whole cells.
ex. testes and ovaries |
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Term
| Methods of Exocrine Gland Secretion |
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Definition
Merocrine (eccrine) – release secretions by exocytosis (most glands). Most common type of secretion.
ex. pancreas glands, tear glands, gastric glands.
Holocrine – cells disintegrate to release secretion
requires continual replacement of cells.
ex. oil producing sebaceous glands.
Apocrine – release secretion by budding off cytoplasm from apical surface. Though they may just as likely secrete the same way as merocrine glands.
ex. mammary glands, sweat glands. |
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