The Endocrine System Flashcards
What is the difference between the endocrine system and the nervous system?
The nervous system regulates the activity of muscles and glands via electrochemical impulses delivered by neuron’s and those organs respond within milliseconds. The endocrine system influences metabolic activity by means of hormones which are chemical messengers released into the blood to be transported throughout the body.
What does the endocrine system do?
It interacts with the nervous system to coordinate and integrate the activity of body cells.
What are the major processes controlled and integrated by the endocrine system?
Reproduction; growth and development, Maintenance; of electrolytes, water,nutrient balance, and Mobilization of body defenses.
What is endocrinology?
The scientific study of hormones and endocrine organs
What are endocrine glands?
Also known as ductless glands they produce hormones and lack ducts, they typically have a rich vascular and lymphatic drainage that receives their hormones, as most are usually arranged in chords and branching networks.
What do the endocrine glands include?
The pituitary,thyroid,parathyroid, adrenal,and pineal glands.
What is the hypothalamus in the endocrine system?
It is a neuroendocrine organ, as it performs its neural functions in addition to the production and release of hormones.
What are hormones?
Long distance chemical signals that travel in the lymph or blood of the body and regulate the metabolic function of other cells within the body.
What are autocrines?
Chemicals that exert their effects on the same cells that secrete them.
What are paracrines?
They act locally but affect cell types other than those releasing the paracrine chemicals.
Give me an example of a homeostatic imbalance of the endocrine system
In certain Cancer tumor cells synthesize hormones identical to those made in the normal endocrine glands and lead to uncontrolled secretion that could lead to problems due to hormone-mediated pathology
Hormones can be classified by ?
Either amino acid based in which the vary in sizes of amino acid derivatives, to peptides, and proteins or steroids which are synthesized from cholesterol in which only gonadal and adrenocortical hormones are steroids
A given hormone influences the activity of only certain tissue cells referred to as target cells by altering their cellular activity.
True
Hormones can typically produce one or more of the following changes, what are they?
1) alters plasma membrane permeability or membrane potential, or both,by opening or closing the ion channels. 2) stimulates the synthesis of proteins or regulatory molecules such as enzymes within the cell. 3) activates or deactivates enzymes. 4) induces secretory activity 5) stimulates mitosis.
What is the difference between water soluble and lipid soluble hormones?
Water soluble hormones typically act on receptors in the plasma membrane and lipid soluble hormones act on intracellular receptors within the cell. Keep in mind there are exceptions.
How does the cyclic AMP signaling mechanism work?
1) The hormone acting as the first messenger binds to its receptor on the plasma membrane. 2)binding causes activation of the G protein when GDP is displaced by GTP acting like a switch. 3) G protein binds to adenylate cyclase enzyme where it is hydrolyzed and deactivates the G protien. 4) For as long as cyclase generates a second messenger cAMP from ATP. 5) cAMP activates protein kinase which activates some proteins and inhibits others.
What enzyme degrades cAMP?
Phosphodiesterase
What signaling mechanism does oxytocin use? And how does it work.
PIP2 The PIP two – calcium signaling mechanism involves a G protein and a membrane bound to factor in this case an enzyme called phospholipase C then splits PIP2 phospholipid into diacylglycerol DAG then into inositol triphosphate. Like DAG cAMP activate a protein kinase enzyme which triggers responses within the target cell where IP3 releases calcium from intracellular storage sites. By directly altering the activity of specific enzymes and channels or by binding directly to calmodulin.
In order for a target cell to respond to a hormone the cell must have a specific protein receptors on its plasma membrane or in its interior to which that hormone can bind
True
Although binding of the hormone to the receptor is is the crucial first step. What are the three factors that are equally important in the activation by the hormone receptor.
1) blood levels of the hormone
2) relative number of receptors for that hormone on or in the target cells
3) affinity (strength) of the binding between the hormone and the receptor
What is up-regulation?
When the target cell form more receptors in response to rising blood levels of the specific hormone
Down regulation involves the loss of receptors due to desensitization of the target cells preventing it from over reaction to the persistently high hormone
True
What are the types of hormone interactions at target cells?
There are three types of interactions which are as follows; (1) Permissiveness - is the situation when one hormone cannot exert its full effectiveness without another hormone being present. (2) Synergism- hormones occurs in situations where more than one hormone produces the same effects at the target cell and their combined effects are amplified. 3) Antagonism- may compete for the same receptors, acting through different metabolic pathways.
What are the three types of stimuli that trigger endocrine glands to manufacture and release thier hormones
Humoral,neural, and hormonal stimuli
