Chapter 7 Flashcards
What is a hormone?
A hormone is a chemical messenger that gets secreted into the blood by specialized epithelial cells
Are hormones a part of the nervous or endocrine system?
They are a part of the endocrine system even if they are secreted by endocrine cells/ glands located in nervous tissue
Compared to neurotransmitters, do hormones have faster or slower responses?
Slower responses as a result of having to travel farther (in some cases)
Do hormones only reach far distances?
No, they can act on far away targets or act locally
Compared to neurotransmitters, do hormone effects last longer?
yes
Between endocrine and nervous which system uses both chemical and electrical signals for communication?
Nervous system
Which system uses just chemicals for communication? And what are the chemicals? Where do they go?
The endocrine system uses just chemicals which are the hormones that travel through the bloodstream
Which cells are targets for hormones?
Any cell in the body that has the receptor
What are the endocrine system glands that are located in the brain?
the hypothalamus
pituitary
pineal
Which glands in the endocrine system are located at the neck?
the thyroid gland and the parathyroid glands
How many parathyroid glands are there and where are they located?
there are 4 and they are located on the dorsal side of the thyroid
What does the pineal gland release?
melatonin
Which systems is the thymus gland a part of?
endocrine and immune
What is the function of the pancreas?
to help regulate metabolism
Where is the thymus gland located?
In the chest
Which of the the endocrine system glands located in the abdominal region of the body?
the adrenal glands and the pancreas
What are the endocrine glands that are a part of the gonads?
ovaries and testes
Where can endocrine cells/ hormone producing cells be found in the body?
All over they do not have to a part of a specific gland
What are a couple of organs/organ systems that have endocrine cells?
the heart and the digestive system
Are hormones secreted at high or low concentrations compared to other communication molecules?
low concentrations
what is the definition of a ligand?
a molecule that binds to a receptor and then has an affect on that cell
are hormones ligands?
yes
What kind of hormones have their receptors inside of the cell/past the cell membranes?
steroid hormones
What effect do steroid hormones have?
They have a slower acting and longer lasting effects for example it can stimulate transcription and translation
Are all hormones steroid hormones?
no
What is the name of the molecule that makes hormones steroid hormones?
cholesterol which is why it is important
What are some examples of steroid hormones?
testosterone, progesterone, estrogen, and cortisol
What is half-life?
it is the amount of time it takes for a hormone to be reduced in the blood concentration by 50%
How do hormones break down?
The molecules that make up a specific hormone break down over time and then get excreted through the kidneys
How long do neurotransmitters effect last? What about hormones?
neurotransmitters- seconds
hormones- hours to days
What makes an endocrine pathway simple?
That there is only one endocrine gland involved
In the simple endocrine pathway, what is both a sensor and a integrating center?
the endocrine cell
In a simple endocrine pathway, what is the output signal?
the hormone
More often than not, do hormones provide positive or negative feedback?
negative
What is an example of a simple endocrine pathway?
The parathyroid gland which can detect low calcium levels in the plasma
What does the parathyroid gland do with low calcium in the plasma in a simple endocrine pathway?
The parathyroid gland:
- senses the low calcium amount
- integrates the information
- releases the parathyroid hormone into the bloodstream
What structures in the body does the parathyroid go to? and what is the effect of it?
-It will go the bones to increase the reabsorbtion of calcium (by breaking down bone to release calcium into the blood)
-the kidneys will reabsorb calcium to make sure it is not secreted via urine
What is another example of simple endocrine pathway?
The pancreas releasing insulin
What are the different ways the pancreas can be stimulated?
- an increase of blood glucose
- the presence of food in the gi tract
- endocrine cells in the small intestine releasing GLP1
What does the pancreas release in response to high blood glucose?
insulin
What is the effect of insulin?
It will go to the target tissues where those tissues will increase the use and uptake of glucose which lowers the levels of it in the blood
Which hormone has the opposite effect of insulin on glucose levels?
glucagon
How does the nervous system affect endocrine responses?
- intergrate stimuli in endocrine reflexes
- change the hormone secretion levels
What are the 3 major groups of neurohormones that get secreted in the blood.
- adrenal gland releases catecholamines
- hypothalamus secretes oxytocin and anti-diuretic hormone (ADH)
- the hypothalamus also produces releasing and inhibiting hormones that direct the activity of the anterior pituitary
What are catecholamines?
-norepinephrine
-epinphrine
-adrenaline
What are neurohormones?
a hormone that is released by neuron and that goes into the blood
What tissue is the anterior pituitary made up of?
endocrine tissue
What tissue is the posterior pituitary made up of?
It is an extension of the hypothalamus tissue
Where is the the hypothalamus located in relation to the pituitary gland?
just above it
The pituitary glands sits on what bone structure of the skull?
the stella turccia
Is the posterior hypothalamus glandular tissue or neural tissue?
neural
What is a releasing hormone?
A hormone that stimulates the release of another hormone
How to hormones form the hypothalamus get released via the posterior pituitary?
The hypothalamic neurons cell bodies remain in the hypothalamus but the hormone moves down the axon to the posterior pituitary to the axons that are specialized for exocytosis and in the posterior pituitary into the blood
Does the posterior pituitary make any hormones?
No
What is the affect of the Anti-diuretic hormone?
It has the kidney retain water to maintain proper osmolarity levels and it can affect aggressive behavior in the brain
Where is oxytocin produced and released?
Produced in the hypothalamus
released in the posterior pituitary
What are the two target tissues of oxytocin and what are it’s effects?
Uterus- increases muscle contraction during labor which is stimulated by the baby’s head stretching the cervix
Mammary glands- causes milk ejection which can be brought on by suckling or the baby crying
How does oxytocin affect the brain of everyone?
It affects social behavior such as emotional bonding, empathy, and maternal behavior
Where is the antidiuretic hormone (ADH) produced and released?
It is produced in the hypothalamus and released by the posterior pituitary
What are the targets of ADH/ vasodepressin?
Kidneys- helps regulate the osmolarity of the blood by retaining water to reduce osmolarity - happens when your dehydrated
Brain- aggression/ aggressive behavior
What is ADH called when its in the brain?
Vasopressin
What are releasing hormones?
Hormones from the hypothalamus that stimulate the release of hormones from the anterior pituitary
What are inhibiting hormones?
Hormones from the hypothalamus that go to the anterior pituitary to inhibit the release of a hormone
What are trophic hormones?
They are hormones that control or regulate the release of other hormones
How many hormones from the anterior pituitary are trophic?
5
What is the hypothalamic-hypophyseal portal system?
It is a system that allows for the blood from the hypothalamus to go directly to the anterior pituitary
Are the hormones going from the hypothalamus to the anterior pituitary released at high or low concentrations and why?
They are released at low concentrations because they do not have to travel very far to get directly to their target
What is the hypothalamic hormone that regulates the production of prolactin from the anterior pituitary? Is it inhibiting or releasing?
Dopamine and it is tonically inhibiting the release of prolactin which is only stimulated by pregnancy
What is the target of prolactin?
Mammary glands
What does TRH stand for?
Thyroid releasing hormone
TRH stimulates the release of what anterior pituitary hormone?
TSH or the thyroid stimulating hormone
What is the target tissue of TSH and what is its response?
The target tissue is the thyroid gland to release the thyroid hormones T3 and T4
What does the hypothalamic hormone CRH mean? Is is inhibiting or releasing?
Adrenocorticotrpohic hormone and it is releasing
What anterior pituitary hormone does CRH stimulate?
ACTH or the Adrenocorticotrophic hormone
What tissue does the ACTH hormone effect and what is it’s response?
It effects the adrenal cortex to release cortisol
What does the hypothalamic hormone GnRH stand for? is it inhibiting or releasing?
It stands for gonadotrophic releasing hormone
Which two anterior pituitary hormones does GnRH effect?
FSH- follicle stimulating hormones
LH-luteinzing hormone
What are the targets for LH and FSH?
The Gonads where they produce adrogens, estrogens, and progesterone
What is the response form the gonads?
Ovaries - ovulation or production of an ooocyte
testes- sperm production
What are the two hypothalamic hormones that effect the growth hormone? And what are their effects?
CHRH- growth hormone releasing hormone
Somatostatin- growth hormone inhibiting hormone
Where are the targets of the growth hormone? Which one is trophic? Which one is not?
Liver (trophic) - to produce insulin like growth factors like for cartilage with plays a role in height
General tissues (not trophic) - directly stimulates tissue and cell growth
What are factors that effect GH or growth hormone?
It can be affected by stress/ cortisol and if a lot of that happens in childhood it can actually stunt growth
What is the hypothalamic pituitary feedback system?
It is how hormones are regulated via negative feedback
What are the 3 intergrating centers in the hypothalamic pituitary feedback system?
-hypothalamus
- anterior pituitary
- target tissues
What happens in long loop of the hypothalamic pituitary feedback system?
The hormone secreted by the target blocks the secretion of the hypothalamus or the anterior pituitary
Why is called the long loop in the hypothalamic pituitary feedback?
because it is the feedback loop that has to travel the longest
What happens in the short loop of the hypothalamic pituitary feedback?
The hormone secreted by the anterior pituitary suppresses the hypothalamus
What happens in the ultrashort loop of the hypothalamic pituitary feedback system?
The hypothalamus or the anterior pituitary inhibit themselves so once they release a hormone they will surpress it temporarily
What is an example of a long loop feedback system?
The use of cortisol or testosterone. Either way the presence of the hormone in the blood inhibits the activity of the hypothalamic and anterior pituitary to maintain normal levels. If the amount of the hormone in the blood gets too low, then the hypothalamus and the anterior pituitary pick up their activity to maintain normal levels
What is the purpose of the hypothalamic pituitary feedback system?
To maintain homeostatic levels of hormones in the blood
What are some endocrine glands that are examples of ultrashort regulation loop?
The adrenal gland and the hypothalamus
What is the hypothalamic hypophyseal portal system?
It is the system of two capillary beds that are connected by portal veins and it it allows for hormones from the hypothalamus to go directly to the anterior pituitary
Can multiple hormones be in the blood at the same time?
Yes
What are synergistic hormones?
They are hormones that carry out the same function but, when they are together they have a greater effect than if it was 2 or 3 together
Are glucagon, epinephreine, and cortisol synergistic, antagonistic, or permissive? And what do they have an effect on?
They are synergistic since they all increase the blood glucose levels
What are permissive hormones?
It is when a hormone cannot fully exert its full effects or fufill it full potential unless the second hormone is present
What are some examples of permissive effects?
- Progesterone and estrogen (progesterone is only active in cells that respond to estrogen)
- Thyroid hormones are needed to reach full sexual maturity
- Hormones of pregnancy are needed for prolactin to be able to produce milk
What does it mean for hormones to be antagonistic?
It means that the hormones involved have the exact opposite functions
What is an example of antagonistic hormones?
Insulin and glucagon because:
-insulin builds up excess glucose in adipose tissue
-glucagon breaks down glucose in the liver
What does hypersecretion of a hormone mean?
That the gland that is responsible for making the hormone is producing too much
What is a common cause of hypersecretion?
Tumors on the gland that is producing the hormones
How does hypersecretion of a hormone affect the anterior pituitary and the hypothalamic hormones of that pathway?
It lowers the levels of those hormones as a result of negative feedback
What does hyposecretion of a hormone mean?
It means that the hormone is being produced in small amounts
What often causes hyposecretion?
Atrophy - decrease in size or wasting of the target gland for the specific hormone
What is the effect of hyposecretion on the anterior pituitary and the hypothalamic hormones?
That the hypothalamic and anterior pituitary hormone levels are going to be high since they are going to try to stimulate the target tissue to producing more of the specific hormone
What happens in an abnormal target response?
An abnormal target response is when something is wrong with the target cell or the signaling pathway meaning it cannot respond to the hormone let alone send out the signal to produce another one
Out of hyper, hypo, secrection and abnormal target responses, which one is the hardest to diagnose? And why/how is it done?
Abnormal target responses is the hardest because unlike hypersecretion and hyposecretion which can be identified by a blood sample which measures the levels of the pituitary and target hormones. But with the abnormal target responses, something is wrong with the target cell or the signaling pathway response which affects the response to the hormone and may need genetic testing for
What can cause abnormal target responses?
A receptor mutation or a signaling pathway mutation
What does primary pathology mean?
It means that the endocrine gland/ target gland is impaired in some way
How does a primary pathology appear in relation to the other hormone levels?
It means that levels of the target hormone would be the opposite to that of the stimulating hormones from the hypothalamus and the anterior pituitary which would indicate that something is wrong
What does the secondary pathology mean?
It means that there is something wrong in the anterior pituitary
How does the secondary pathology look like relative to the other hormone levels?
It means that the anterior pituitary would be producing the opposite levels of hormone that that they hypothalamic hormone would ex hypothalamic hormone is low and the anterior pituitary hormone is high
What is tertiary pathology?
It is when there is something wrong with the hypothalamic hormone
Are tertiary pathologies common? An what can be the effects of them?
No they are not common and they can be lethal because since the hypothalamus is so small it is hard to try to do anything that can help it or fix it without seriously harming the patient but the pathology can also be lethal as well
How does a teritary pathology look hormone level wise compared to the other hormones in the pathway?
It means that even there is a high or low amount of the target hormone the levels of hypothalamic hormone is the same when it is supposed to be the opposite to regulate it
What are the effects of oxytocin?
- provides positive feedback during childbirth
- controls milk ejection from mammary glands
- important in pair bonding
What is the effects of ACTH on the adrenal cortex?
- to produce glucocorticocoids (cortisol is the main one)
- glucose, protein, and fat metabolism
What are the effects of Growth hormone?
- production of insulin like growth factors from the liver
- stimulates growth in tissues
