Endocrine Physiology Flashcards
What are the two systems responsible for responding to external and internal changes in the body?
Endocrine and nervous system.
Endocrine system acts _____ to _____. Explain this.
Cell to cell. Can be long distance - a hormone from one cell released into blood stream and circulated. Levels rise through the whole body but only cells with that receptor can have a response.
Nervous system acts ____. Explain this.
Neurotransmitter created by one cell acts on another target cell which is local to producing cell. Bind to a receptor also.
What are the three different types of factors released by the two different systems?
Autocrine, Paracrine and Endocrine.
Explain Autocrine factors.
Secreted or surface bound growth factors and cytokines which are expressed by a cell to act on itself or adjacent cells of same lineage.
Explain Paracrine factors.
Secreted or surface bound growth factors or cytokines expressed by a cell and act locally within tissue. Don’t have to act on same cell as releaser by on adjacent or nearby cells.
Explain Endocrine factors.
Secreted hormones produced in an endocrine organ to have effects on the distant organs - effect all target tissues in the body at once.
What is the role of autocrine and paracrine factors?
Regulate migration, proliferation (cell division), differentiation (maturation into a cell type), activity (function) and apoptosis of cells.
How does autocrine and paracrine signaling work?
Cytokines and growth factors exert their effect on target cells by binding to a specific cell surface receptor and when a ligand binds to receptor there is a ligand receptor complex that activates the intracellular pathways that change the activity or function of that cell.
What is the role of the endocrine system?
Controls activities that don’t require immediate adjustment - exerts effects for longer periods of time. Endocrine system transports hormones through the blood.
What are some processes under hormonal control?
Metabolism, internal environment regulation, reproduction and growth and development
How do hormones act on target cells?
Control rate of enzymatic reactions, control iron and molecular transport and control gene expression and protein synthesis.
What is a tropic hormone? Give an example.
Hormone that acts to regulate the reproduction and secretion of another hormone. TSH (Thyroid stimulating hormone) secreted by anterior pituitary - stimulate gland to secrete thyroid hormone.
What are the three chemical classes of hormones?
Peptide/protein hormones composed of linked amino acids.
Steroid hormones from cholesterol
Amines modified from tryptophan or tyrosine.
How can hormones be grouped if not chemically?
By solubility:
Peptides and amines hydrophilic ( cant cross cell membrane)
Steroid hormones lipophilic - can easily cross cell membrane
