Primary Tissues Flashcards
What is a tissue?
A collection of specialised cells with a distant function
How do different cell types arise from differential gene expression?
Cellsonly express a subset of genes in their genome, this provides key characteristics for cell type. Selective expression and “gene-silencing”, such as PTM and splicing results in different cell types. Differentiation programmes determine cell structure and function.
What is an organ?
Several tissues grouped together
4 different tissues found in the body
epithelia
connective tissue
muscle
neural tissue
Briefly explain properties of epithelia
works to cover an exterior with a layer of cells, can be varied in the shape and arrangement of cells.
Main functions of epithelia?
secretion, absorption, transport, protective/selective barrier
surface modifications of epithelia?
microvili: enhance absorption with actin in core
cilia: movement and absorption, motile contain microtubules
main types of junctions in epithelia and their functions
tight: sealing
desmosome: strengthen cell links by intermediate filaments
gap: connect cytosols of adjacent cells for passage of tiny molecules
adherens: links movement proteins by actin
What structures in the neuron are responsible for conducting stimuli to and from the cell?
Axons direct stimuli away and dendrites direct stimuli to the cell.
Explain the biological significance of the myelin sheath in neurons
Myelin sheath found around axon is discontinuous and enhances conduction. In CNS one oligodendrocyte makes one internode and in PNS: one schwann cell makes one internode
Important glial cells and their functions
CNS: oligodendrocytes: myelination astrocytes (fibrous and protoplasmic): maintain epithelia microglia: phagocytosis and antigen presentation to lymphocytes Ependyma: lining in CNS cavities PNS: schwann cells satellite cells
3 types of muscle and their properties
skeletal: striated, coordinated contraction, voluntary or involuntary control, cylindrical multi-nucleated cells with nucleus in the periphery
cardiac: striated coordinated contraction, involuntary control, rectangular mono-nucleated cells nucleus in centre of cell
smooth: non-striated, coordinated contraction, involuntary, spindle shaped mono-nucleated cells with nucleus in the centre of the cell
3 types of fibrocollagenous tissue
loose: spaces of proteoglycan (protein bound to monosaccharide)
dense: packed with collagen
reticular: network formation
What cell types are found in fibrocollagenous tissue?
macrophages: phagocytose foreign bodies/present antigens
mast cells: synthesise histamine (for immune response)
plasma cells: synthesise antibodies
stem cells
blood cells
adipocytes
Function of cartilage
Flexibility, strength and smooth muscle joint movement
