Epithelial Cells and Tissues Flashcards
What are the contents of the nucleus?
Nucleoplasm, nucleolis, and chromatin. Heterochromatin is the less active DNA.
What are the densities of the large and small subunits in the prokaryotic ribosome?
Small subunit is 30s, large subunit is 50s, and the total ribosome is 70s
What is the density of the large and small subunit of the eukaryotic ribosome?
Small subunit is 40s, large subunit 60s and total ribosome 80s.
What is the nuclear lamina and what is it involved in?
The specialised type of cytoskeleton that has developed on the internal surface of the nuclear envelope - important for assembly and disassembly of the nuclear envelope in cell division.
How can the rough ER and smooth ER be described as?
Rough ER is granular, smooth ER is agranular.
What are the functions of the SER?
Detoxification and lipid metabolism - also a storage of Ca2+ ions in the cells (important in cell signalling).
What are peroxisomes and what do they do?
Membrane bound organelles that contain enzymes involved in lipid and oxygen metabolism, the enzymes can crystallise to form the cores that are observed in TEM. Enzymes include oxidised, catalases and peroxidases.
What is the function and structure of microtubules?
Polymers of a and B tubulin heterodimers (two protein monomers) that are 20nm thick. They act as tracks for motor proteins, and are a component of the cilia and flagella. Also act as spindle fibres in mitosis.
What is the structure of cilia and flagella?
Microtubules are present in the 9 + 2 formation. Attached to ATP dependent motor proteins that distort the cilia or flagella to cause movement.
Where do microtubules originate from?
microtubule organizing center (MTOC)
What are the intermediate filaments present in epithelia?
Cytokeratins
What are the intermediate filaments found in mesenchymal cells?
Vimentin
What are the intermediate filaments found in neurones?
Neurofilament protein
What are the intermediate filaments found in muscle cells?
Desmin
What is the function of intermediate filaments?
Give mechanical strength to the cell, and connect cells together through the desmosomes. Nuclear lamins are intermediate filaments integrated in the nuclear envelope which stabilises the envelope.
What are microfilaments and what is their function?
Monomer of globular actin, and polymer of filaments actin. Gives the cell its shape and allows it to contract and expand (eg. Muscle cells/mitosis). Can be associated with myosin in the sarcomere. Associate with the adhesion belts in epithelia or epithelium.
What are the main cell types?
Connective, contractile, epithelial, haemopoietic, and neural.
Give some examples of connective tissue cells
Fibroblasts, chondrocytes (cartilage), osteocytes (bone).
Give some examples of contractile tissues.
Skeletal muscle, cardiac muscle, smooth muscle
Give some examples of haemopoietic cells
Blood cells, tissue-resident immune cells, bone marrow cells
Give some examples of neural cells
Neurones and glial cells (support cells)
What are epithelial cancers called?
carcinomas
What are mesenchymal cancers called (connective tissue and muscle)?
Sarcomas
What are haematopoietic cancers called?
Lymphomas (from lymphocytes) and leukaemia (from bone marrow cells).
What are neural cell cancers called?
Neuroblastomas (in neurones) or gliomas (from glial cells).