Question | Answer |
What is a tissue? | A group of specialised cells with a distinct function. |
What are the advantages of having tissues? | Division of labour and coordinated function for tissues.
Larger organisms possible, support and motility- exploitation of resources not available to single cells. |
What regulates gene expression? | Transcription factors. |
What are the four basic types of body tissue? | Epithelia.
Connective tissue.
Muscle.
Neural tissue. |
What is the function of a tight junction? | Sealing. |
What is the function of desmosomes? | Strengthen cell links. |
What is the function of gap junctions? | Connect cytosols of adjacent cells for very small molecules. |
What is the function of adherens junctions? | Spots of connection linking movement of proteins (actin). |
Where do epithelial cells sit? | On an amorphous basement membrane made of extracellular matrix molecules. |
What is the function of the BM? | Anchor for epithelial cells.
BM contains proteins that link to the surface of epithelial cells.
Contains filamentous proteins that provide strength. |
What is the function of the nervous system? | Collects, processes/integrates and sends information (cells are adapted for local and distant cellular communication). |
How many neurons are in the central nervous system? | 100 billion neurons. |
What are the key characteristic functions of neurons? | They separate cells that communicate by releasing chemicals by secretion at the ends of cell processes.
Therefore a neuron is no more than an elongated secretory cell. |
What do dendrites do? | Direct stimulus towards the cell. |
What does the axon do? | Directs stimulus away from the cell. |
When does secretion occur in the nervous system? | At the end of axons.
Into specialised intracellular gaps called synapses (and neuromuscular junctions). |
What is the function of myelination? | It is a fatty sheath- discontinuous with periodic gaps.
It enhances conduction. |
What is an Oligodendrocyte? | One of the cells of the glia, responsible for producing the myelin sheaths of neurons of the CNS. |
What is a glial cell? | The special connective tissue of the CNS. |
What are examples of glial cells in the CNS? | Oligodendrocytes (myelination).
Astrocytes.
Microglia.
Ependyma (lining cells of the CNS cavities). |
What are examples of glial cells in the PNS? | Schwann cells (myelination).
Satellite cells (support cells in ganglia). |
What is the function of astrocytes? | Metabolic and mechanical support.
In CNS scar tissue also. |
What is an alternative function of glial cells? | Resident macrophages of the CNS.
Involved in Phagocytosis and antigen presentation. |
How many types of muscle cell are there? | 3. |
What is the structure and function of skeletal muscle? | Striated, coordination contraction under direct voluntary.
Can be involuntary in reflexes. |
What is the structure and function of cardiac muscle? | |