exam 1 Flashcards
Tissues
groups of cells with similar structure and function
Tissues types
- Epithelial: covers, lines
- Connective: supports
- Muscle: movement
- Nervous: control
Epithelial Tissue
Organizes and compartmentalizes the body outside and in.
Forms sheets and layers to cover the outside of body and the organs; lines the interior of the body cavities and the hollow organs. Layers can be rolled into a tube and act as a duct
epithelial Functions
Protect, cover, line, filter, absorb, secrete, sense.
epithelial examples
Skin, surface of kidneys and liver, lining of stomach and lungs, ducts in kidneys, liver, salivary and mammary glands.
Characteristics of epithelial
- tightly packed
- polar, apical, basal
- lateral surfaces connected
- avascular
- ex. No blood vessels
- innervated
- nerves are present
Cellular attachments
- plasma membrane attachments
- junctional complexes
- major types
- tight junctions
- desmosomes
- gap junctions
Tight junctions
- fusion of outer plasma membranes
- no leaks
- forces material to pass through cells, IF it can
Desmosomes
- strong mechanical coupling
- plaque
- cytoskeleton
- in tissues with tension & stretching
- skin, heart, uterus
Gap junctions
- channel proteins
- connexions
- join cytoplasms
- exchange materials
- amino acids, CHOs
- electrical signals
Basement membrane = basal lamina
- foundation made by epithelial cells
- nonliving fibers
- cements cells to underlying tissue
- helps keep cells in place
Surface specialization
- surface vary
- smooth
- cilia: move
- microvilli: do not move
- brush border
- keratin
Classification of epithelia
- number of layers of cells
- simple or stratified
- shape of cells
- squamous, cuboidal, columnar
- presence of surfaces specialization
- cilia, keratin, etc
Simple squamous epithelium
- delicate and thin
- flat and smooth
- lining surfaces
- lung, vessels, body cavities, kidney
Stratified cuboidal epithelium
- large excretory ducts
- sweat glands, mammary glands, salivary glands
Transitional epithelium
- description
- basal layer cuboidal or columnar
- superficial layer squamous
- leakproof membrane
- expand and contract
- bladder, ureters, urethra
Simple cuboidal epithelium
- single layer of cube-shaped cells
- nuclei aligned in single row
- secretion (smooth) and absorption (microvilli)
Simple columnar epithelium
- cells elongated, close together
- sometimes cilia or microvilli
- nuclei aligned at base
- absorption and secretion
Stratified squamous epithelium
- multilayered
- protect underlying tissues
- for mechanical and chemical stress areas
- mouth, esophagus, vagina
- outer layer continually worn off
- replaced at equal rate from cells in deeper layers
Named for surface layer
- replaced at equal rate from cells in deeper layers
Characteristics of Connective Tissues (CT)
- most abundant tissue by weight
- vascularized (unlike epithelium)
- 3 distinct components
- cells, extracellular fibers, ground substances
- ex. Blood, tendons, fat, cartilage, bone
Components of Connective Tissue (CT)
ground substances, cells, extracellular fibers
3 surfaces of epithelial cells
Basal, apical, lateral
Components of Connective Tissue (CT) - Ground Substance
- ground substance: ranges from liquid to gel to solid
- amorphous homogenous material
- glycoproteins
- medium for nutrient/waste exchange
- envelopes/protects cells
- obstacle for microbes
- amorphous homogenous material
Components of Connective Tissue (CT) - Cells
- Fixed cells
- fibroblasts, adipocytes (fat cells), and reticular cells.
- wandering cells
- mast cells, leukocytes (white blood cells), and macrophages (fixed and wandering)
