Group of closely associated cells that perform related functions and are similar in structure
What are the four projections found on the apical surface of epithelial tissue?
Microvilli, Cilia, Cell Junctions, Basal Lamina
What projection maximizes surface area, for example in the small intestine absorbs nutrients into blood?
What projection aids in movemen of mucous/other substances across epithelial surfaces for example in the respiratory tract, moves contaminated mucous in order to spit or swallow?
What projections anchor epithelial tissues to connective tissue in order to recieve nutrients, oxygen and exchange carbon dioxide and waste?
What must happen in order for epithelial tissue to recieve oxygen an nutrients?
oxygen and nutrients from the capillaries in the connective tissue must diffuse to get to the next tissue
What kind of epithelial tissue do we have for our skin an why?
Stratified (multiple layers) because we need protection from mechanical stress and it is constantly being replaced
Single layer of flattened cells with disc-shaped central nuclei an sparse cytoplasm, the simplest of epithelia
Allows passage of materials by diffusion and filtration in sites where protections in not important; secretes lubricating substances in serosae
What are the two key thoughts when determining between simple vs stratified?
Movement an exchange, we want something with one/thin layer in order to have movement or exchange occur easily
What is unique about simple squamous?
it is too thin to conatin any type of organells or to house any machinery to carry out absorption
Where do we find simple squamous and give one good reason why.
In the repiratory tract because when we inhale air, there is more oxygen in the air than there is in our blood, so the oxygen will difuse into blood an we need these tissues to be very thin in these areas to help the diffusion/exchange process
Where do we find simply cuboidal and give one good reason why.
Digestive tract beacuse it requires energy for absorption and secretion so we need area to keep organelles/machinery for absorption but also tissue so that we can have movement an exchange.
single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucous-secreting unicellular glands
absorption; secretion of mucous, enzymes and other substances; ciliated type propels mucous (or reproductive cells) by ciliary actions
Where do we find simple columnar and give one good reason why.
In the digestive tract going from stomach to anal in order to move things through the digestive system but still have exchange and movement
single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; may contain unicellular glads and bear cilia
Pseudostratified ciliated columnar
secretion, particularly of mucus ; propulsion of mucus by ciliary action
Pseudostratified ciliated columnar
Where do we find pseudostratified ciliated columnar and give one good reason why.
found in sperm carrying ducts and repsiratory tract in order to move things along
thick membrane comosed of several cells layers; surface cells are flattened while basal cells are columnar and cuboidal, surface cells are full of keratin and dead, basal cells active in mitosis
what are the three types of protein fibers in the extracellular matrix?
collagen, elastic and reticular
what is interesting about ground cells/matrix in areolar tissue?
there is alot of matrix between the cells
several cell layers; basal cells are usually cuboidal; superficial cells elongated and columnar
resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surfaces cells dome shaped or squamouslike, depending on degree of organ stretch
streatches readily and permits distension of urinary organ by contained urine
what does glandular tissue consists of?
Exocine: release products into ducts/tubes where they are delivered to specific locations.
Endocrine: products are released into blood circulation where they interact with certain hormones
What are the three cell junctions or cell to cell contacts?
desmosomes, tight juntions, and gap junctions
anchor cells together where high mechanical stree and forces are present such as in the heart with constant movement that may cause damage
barrier to keep things from getting from one tissue to another such as in the blood-brain and blood-testes barrier
cell to cell contact where passages travel from one cell to the next such as electrical impulses and flow of nutrients such as allowing a whole chamber to contract all at once
Name the four sub classes of connective tissues
Connective Tissue Proper, Cartilage, Bone Tissue, Blood
List some characteristics of cartilage
does not regenerate well, provides structure and shape, only chonrocytes, 80% water, avascular and not innervated
List some characteristics of bone
support (framework), protection and nutrient storage(calcium and phosphate); osteoblasts and osteoclasts and blood vessels