Flash Cards
beneficial stress
eustress
anything that disrupts homeostasis
stress
what happens during eustress
there is a deviation and then normal homeostatic mechanisms bring it back into range
detrimental stress that causes further deviation from homeostatic norms
distress
who was Hans Selye?
an Austrian-born physician who noticed that a bunch of his patients who wer experiencing various ailments all had the same blood chemistry, so he said that “stressful events lead to a disease state”. he was laughed out of Europe and came to America where he developed the General Adaptation Syndrome
says that stress occurs through a well-developed sequence of steps
general adaptation syndrome
what are the steps in the general adaptation syndrome
- alarm reactions
- resistance reactions
- physiological exhaustion
when does the alarm reaction stage of the general adaptation syndrome usually occur and what happens during it?
it occurs every time you are presented with a stress. generally takes care of the situation. it is short lived, reverses the stress using the nervous system
what happens if the alarm reactions don’t work during the general adaptation syndrome?
move on to the second stage - resistance reactions
what occurs during the resistance reactions stage of the general adaptation syndrome?
body adapts to longer term stress. this one is slower to respond and often is a hormone response
what happens during the physiological exhaustion stage of the general adaptation syndrome?
body shuts down and without intervention it ends in death
what are the key organs/systems involved in the general adaptation syndrome?
the endocrine and nervous systems
what is the ‘mediator’ of the nervous system, and what is the ‘mediator’ of the endocrine system?
electrical signals/impulses in the nervous system, hormones in the endocrine system
what are the target tissues in the nervous and in the endocrine systems?
muscles, glands, or other neurons in the nervous system, all cells in the human body are targets for at least one hormone of the endocrine system
how quickly do we see a response with the nervous system and how quickly do we see one with the endocrine system?
immediate with the nervous system - from several hours to several days with the endocrine system
how long is the response duration for the nervous and endocrine systems?
the nervous system is short lived while the endocrine system is longer-lived
chemical messengers
hormones
what are hormones produced by?
endocrine glands
do you need a high dose of a hormone?
no, you only need a little bit
what does it mean that hormones are specific?
they only interact with their target cells/tissues
what is a target cell?
specific cell that reacts with a specific hormone. the hormone will bring out some sort of change in that cell
how are hormones classified?
based on how they operate, based on their solubility, and based on their chemistry
what are the two types of hormones based on how they operate?
circulating hormones and local hormones
produced by endocrine gland and circulate in the blood over a distance before they reach their target
circulating hormones
what is an example of a circulating hormone?
the posterior pituitary produces antidiuretic hormone which has to go from the brain to the kidney through the blood
type of hormones that stay in the area near the tissue/gland that produced them. in the interstitial fluid.
local hormones
what are the two types of local hormones?
autocrines and paracrines
hormones that are secreted and affect the cells that produced them - what is an example?
autocrines - endorphins
hormones that affect cells that neighbor the gland that secreted them. what are some examples?
paracrines - prostaglandins and interleukin II
what are the types of hormones that are classified based on their chemistry?
biogenic amines, peptides and proteins, gaseous hormones, steroid hormones, eicosinoids
small hormones that are usually modified amino acids. hormones like T3 and T4.
biogenic amines (NH3)
hormones that consist of chains of amino acid
peptides and proteins
what hormones are peptides and proteins?
human growth hormone, antidiuretic hormone, oxytocin, insulin
what is the only confirmed gaseous hormone in the human body and what cells does it affect?
nitric oxide affects almost every cell
hormones derived from cholesterol. some of the most potent. sex hormones, cortisol, aldosteroid.
steroid hormones
hormones that are derived from arachidonic acid. usually function as a local hormone. typically pull acid from the cell membrane and then convert it into the hormone. prostaglandin
eicosinoids
what dictates the function of the hormone
solubility
how is a lipid hormone able to be transported through the blood?
it must bind to a plasma transport protein, which makes the hormone temporarily soluble in water
do lipid soluble proteins have a hard time passing into the cell?
no
what happens if the lipid soluble hormone is in the target cell?
it will bind to the receptor and form the hormone receptor complex which enters the nucleus, interacts with DNA and activates certain genes. one of the things that is turned on is protein kinases which alter the physiology of the cell.
why do we want hormone reactions inside the cell to be short lived.
because they longer the hormone is affecting the cell, the greater chance of mistakes in DNA that could lead to cancer, since the hormones interact with DNA
what happens if the lipid soluble hormone is not in the target cell?
the hormone will become an inclusion and become recycled
do water soluble hormones have a problem being transported in the blood?
no because they are soluble into the plasma
where do water soluble hormones start to encounter a problem?
when trying to enter the cell
how do water soluble proteins enter the target cell?
the target cell will have a receptor outside the plasma membrane which is linked to a special protein called a G protein which links the outside of the cell to the inside.
what happens after the water soluble hormone has bound to the receptor on the outside of the plasma membrane?
the G protein is activated when the hormone binds. it activates adneylate cyclase which catalyzes the conversion of ATP to cyclic adenosine monophosphate (cAMP) which is the second messenger. cAMP diffuses in the cell, activating enzymes that generate change in physiology
control of the endocrine system. floor of the brain. controls the anterior pituitary gland
hypothalamus
in what areas does the hypothalamus have neurons
it has neurons in the ventral hypothalamus, paraventricular nuclei, and syrapoptic nuclei
what does the anterior pituitary gland secrete into and what types of hormones does it secrete?
secretes into the hypothalamic hypophyseal portal system - secretes releasing hormones and inhibiting hormones
produced by the downward growth of embryonic hypothalamic tissue and has a neural connection to the hypothalamus
posterior pituitary gland
what are the neurosecretory cells of the posterior pituitary gland
supraoptic and paraventricular nuclei secrete neurohormones - oxytocin and antidiuretic hormone
hormone made of nine amino acids that is a positive feedback mechanism. causes uterine contractions, milk ejection, and is called the cuddle hormone
oxytocin
what gland produces oxytocin
posterior pituitary gland
hormone made of nine amino acids that inhibits water secretion in the kidney tubules
antidiuretic hormone
what gland produces antidiuretic hormone?
posterior pituitary gland
“master gland”, the truly glandular part of the pituitary gland
anterior pituitary gland
what hormones does the anterior pituitary gland secrete?
human growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, gonadotropins (follicle stimulating hormone and luteinizing hormone) prolactin
hormone that is used to produce insulin-like growth factors and stimulates body growth in most cells
human growth hormone
what happens when human growth hormone is not produced in proper amounts?
if there is too much, you can get gigantism or acromegaly. if there is not enough you can have pituitary dwarfism
when there are not proper amounts of human growth hormone, does the time of the disorder matter?
yes, if it is before the growth plates close you have gigantism, but if it is after the growth plates close, you get acromegaly
stimulates the release of hormones from the thyroid gland. affects almost every cell in the body - glucose oxidation, heat production, blood pressure, tissue growth
thyroid stimulating hormone
what are characteristics of myxedema (hypothyroid disorder)
low metabolism, cold, puffy eyes, thick, dry skin, goiter, sluggish