Lecture 7 Flashcards
What is the role of endocrine and nervous system and the rest of the body?
Long distance communication
What parts of the body produce hormones within the endocrine system?
Thyroid gland, parathyroid gland, hypothalamus, pituitary gland, pancreas, adreanal glands, ovary and testes
What is the role of the endocrine system?
Regulates growth, reproduction and metabolism
How does the endocrine regulate the body?
With glands and tissues secreting hormones into the blood stream to bind to receptor on target cells in distance parts of the body
What type of hormones bind to receptors on target cells?
Water soluble hormones
How do water soluble hormones initiate a response on target cells?
Travels in blood stream to bind to receptors on the membrane of the target cells -> the binding changes cell activity since hormone cannot enter -> this activates G- protein to turn on the cascade of events inside the cell-> activates cAMP messenger system -> activates protein kinase to phosphorylate other proteins -> protein activate and produce physiological response
Why are second messengers necessary for water soluble hormones?
Since the hormone cannot enter the cell. Uses cAMP as an intercellular messenger to pass on the reaction and is rapidly broken down
How do lipid soluble hormones initiate a response to target cells?
Lipid soluble hormones are unable to travel through the blood therefore need a transport protein to taxi it to the location it needs -> diffuses into cell to nucleus -> hormone uses receptor to bind the DNA and begins transcription -> mRNA to ribosomes to translate to new protein by protein synthesis (mRNA) -> produces physiological effect altering cell activity
Process is slow but has a long lasting effect
What activates the release of hormones in the body (humoral stimuli)?
Condition of the blood
Ex. High [glucose] triggers beta cells in pancreas to release insulin -> insulin tells cells to make glucose receptors and take in glucose
What activates neural stimuli?
Neural stimuli triggers hormones to release
Shock/scare -> sympathetic nervous system triggers preganglionic directly to adrenal medulla -> release of epinephrine and norepinephrine to increase HR and contraction force
What are examples of lipid soluble and water soluble hormones?
Steroids, thyroid hormones - testosterone, estrogen, cortisol
Peptides, proteins, catecholamines - insulin, LH, FSH, GH, glucagon
What is an example of a positive feedback neural stimulus?
Uterine contractions -> hypothalamus -> posterior pituitary to release oxytocin to trigger more contractions by the cervix stretching
What is an example of a negative feedback of hormonal stimulus?
The production of a hormone from one tissue can trigger the inhibition hormone to be released by another tissue
Low meta triggers thyrotropin from hypo -> triggersT3 and T4 to released from thyroid gland and stop the thyrotropin release
What is triggered in extreme external or internal stimulus?
General adaptation syndrome governed by the hypothalamus
What are the stages the body responds to in preparation to stress?
Alarm reaction (fight flight) - increased blood glucose, increase HR, increase breathing, decrease blood to skin and digestion,
Resistance reaction - increase blood glucose (cortisol inhibits insulin release), inhibit immune system, release of aldosterone and ADH
Long term exhaustion from depletion of body resources, K from aldosterone, damage to organs
