Lecture 2 Flashcards
What is a tissue?
Group of similar cells that usually have common embryonic origins and function together to perform specialised functions.
4 types of tissue?
Epithelial, connective, muscle, nervous.
Where does nerve tissue originate from?
Ectoderm.
Where does connective and muscle tissue originate?
Mesoderm.
Where do epithelial cells originate?
Endoderm, ectoderm and mesoderm.
5 different types of cell junction?
Tight, adherens, desmosome, hemidesmosome, gap.
What binds adjacent cells together in an adherens junction?
Adhesion belt - cadherin between plasma membranes, and plaque inside each cell.
How do desmosomes bind cells together?
Cadherin pulls proteins together, whilst plaque on the inside of both cells has keratin filaments protruding from it.
How do hemidesmosomes and desmosomes differ?
Hemidesmosomes bind to the basement membrane instead of another cell.
What are gap junctions?
2 cells connected by connexons (made of connexin).
Two main types of nervous tissue?
Neurons, neuroglia.
What do neuroglia do?
Insulate (non conducting) and protect neurons.
3 types of muscle?
Skeletal, cardiac, smooth.
Structural description of skeletal muscle?
Long, cylindrical cells containing many peripheral nuclei.
Striated and parallel due to myofilament arrangement.
What is skeletal muscle attached to?
Bones of skeleton.
Where is cardiac and smooth muscle found?
Cardiac - walls of the heart.
Smooth - walls of hollow structures, e.g. blood vessels, lung airways.
How does smooth muscle work?
Alternately contracts and relaxes, propelling substances.
Where are the nuclei located in smooth and cardiac muscle?
One in centre.
How are cardiac and smooth muscle connected?
Cardiac - intercalated junctions.
Smooth - connected via gap junctions.
3 functions of epithelium?
Covering body substances.
Lining hollow organs, body cavities and ducts.
Forming glands.
4 characteristics of epithelium?
Forms continuous sheets.
Avascular.
Innervated.
Generally, high proliferative potential.
How are epithelium cells typically fixed to basal lamina?
Hemidesmosomes.
3 types of layering of epithelium?
Simple, pseudostratified, stratified.
3 types of shapes of epithelial cells?
Squamous, cuboidal, Columnar.
