Cells Flashcards
What is exocytosis and endocytosis
Things moving out of the cell
Things moving into the cell
Two important types of Bulk Transport?
Growth factor receptors
Hormone receptors
What are growth factor receptors?
A cell determines whether or not it should grow from growth factors that may be present in the medium around it.
These growth factors are polypeptides often 50-100 amino acids long.
When present in sufficient quantity, a growth factor will stimulate a cell to enter into round of growth and division
What are hormone receptors? How do they work?
Hormones are primarily chemical messengers which regulate metabolism at sites far from they point of origin. At the cell membrane or a receptive cell, the hormone binds to its receptor molecule. The receptor-molecule complex then activates an enzyme that removes two phosphates from ATP and converts it into cyclic AMP (cAMP). Cyclic AMP is the second messenger, which then influences one of more processes or enzymes in the cell.
How can a “disease state” arise? Example?
Any defect in the receptor or decrease in the number of receptors on the cell surface of the target cell can lead to it. An example of this is diabetes mellitus which can result not only from a lack of the hormone insulin, but also from a deficiency or defect in the receptor protein on the target cell.
Terms for Cell Death & Injury: Etiology of disease
Cause
There are two major classes of etiological factors:
Intrinsic (genetic) and acquired (infectious nutritional, chemical, physical). Knowledge of the primary cause of the disease can be made, a disease understood, or a treatment developed.
Idiopathic - Cause is unknown
Latrogenic - Cause is treatment, procedure, error
Terms for Cell Death & Injury: Predisposing factors
Risk factors
Tendencies that promote the development of a disease in an individual.
Terms for Cell Death & Injury: Pathogenesis
Mechanisms of its development. Pathogenesis refers to the sequence of events in the response of cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease. To understand the sequence of events in the development of the disease is as important as the cause since there may be a significant time delay before the disease is expressed.
Terms for Cell Death & Injury: Morphologic changes
Structural Alterations induced in the cells and organs of the body. These changes may be characteristic of the disease or diagnostic of the etiological process.
Terms for Cell Death & Injury: Clinical Significance
The functional consequences of the morphological changes. These changes in different tissues or organs influence normal function and determine the clinical features (signs and symptoms), course and prognosis of the disease.
What is the cells ability to handle normal physiological demands?
Normal homeostasis
What are cellular responses and adaptations?
Cells must adapt to changes in their environments. These adaptations usually represent responses of cells to normal stimulation by hormones or endogenous chemical substances. Cellular adaptions may involve:
Regulation of specific cellular receptors
Induction of new protein synthesis by target cells.
Receptor binding, signal transduction, transcription, translation
Regulation of packaging and release.
types of cellular adaption
Atrophy hypertrophy hyperplasia hypoplasia agenesis metaplasia dysplasia intracellular accumulations
What is cell injury?
Occurs if the limits of adaptive response to a stimulus are exceeded, or in certain instances when adaption is not possible, a sequence of events follows. It is reversible to a point but if the stimulus persists or is severe enough from the beginning, the cell reaches the point of no return and suffers irreversible cell injury and cell death.
What are causes of cell injury?
Hypoxia free radicals physical agents - mechanical forces extremes of temperature - pressure, radiation, electrical injury. Chemical agents microbial agents immune mechanisms genetic abnormalities nutritional imbalences aging
