module 8 Flashcards
What chemicals does the endocrine system use to send signals?
hormones
when a neurotransmitter or hormone from a neuron makes contact with an endocrine cell what is happening?
second pattern of hormone release in the human body
Typically, the endocrine system signal will be slower than the nervous system, but it can still be fast enough to affect the target tissue or cell within minutes. (T/F)
TRUE
The hypothalamus is located just above the ____________ ______in the brain.
pituitary gland
Define target tissue
Any tissue that has a receptor for a hormone
What does it mean when hormone concentration in the blood is very low for a particular hormone?
very small changes in the control mechanisms result in proportionately large effects of that hormone.
the hypothalamus is connected to what 2 glands?
1.anterior pituitary gland (adenohypophysis) by a capillary bed
- posterior pituitary gland (neurohypophysis) by the axons of neurons.
The anatomical set-up allows the hypothalamus to communicate with the anterior pituitary gland with 1._________ and with the posterior pituitary gland with 2.________ ______.
- hormones
- nervous signals
T OR F
One way hormone gets released to the body is when a nervous signal comes into the hypothalamus, causes release of hormones from the hypothalamus itself, travel in the capillary bed to the anterior pituitary, bind to receptors, and trigger the release of another hormone back out into the bloodstream.
TRUE
What are hormones usually regulated by?
“long-loop” negative feedback loops.
What do “long-loop” negative feedback loops do?
allow several places where amount of hormone produced or released can be affected.
In the First Pattern of Release, changes in the 1. ________ concentration of a particular 2.______ molecule or 3.________ ion can affect the amount of 4._________ released from a gland
- plasma
- organic
- mineral
- hormone
T OR F
After the second hormone travels to a gland somewhere in the body and triggers the release of a third hormone it then binds to a receptor and causes no change
FALSE, it causes something to happen in most cases (or not happen in a few cases)
What is the basic pattern ___________ -> anterior pituitary -> _____ -> target ________.
hypothalamus -> anterior pituitary -> gland -> target tissue
When the hypothalamus releases TRH which travels to the anterior pituitary to trigger the release of TSH which travels to the thyroid to trigger the release of T3 and T4 would be an example of what?
The basic pattern:
hypothalamus -> anterior pituitary -> gland -> target tissue
T OR F
There are three basic variations in the second pattern of release
TRUE, the basic pattern, the 1st variation, the 2nd variation
Eating a meal:
Blood sugar lvls rise
V
Pancreas secretes insulin
V
Cells take up glucose
V
Blood glucose levels fall
V
pancreas secretes less insulin
V
Blood sugar lvls rise again
Which pattern of release is this an example of?
First Pattern of Release
what is released by the action potential in the 1st variation?
a neurotransmitter (hormone) from the posterior pituitary to the bloodstream.
In the 1st variation, hormones travel to a
______ ______, bind to a ___________ on that target tissue, and cause something to happen.
target tissue
receptor
when ADH is released from the posterior pituitary to travel to the collecting ducts of the kidneys and triggers more water reabsorption from the urine would be an example of what pattern of release?
The 1st variation
hormones -> target tissue -> bind to a receptor on that target tissue -> cause something to happen.
Something can’t get too high or too low if the negative feedback loop is working properly (T/F)
TRUE
The cell does not need to have a receptor for the hormone to bind (T/F)
FALSE, the cell MUST have a receptor for the hormone to bind
The 2nd variation of release occurs when the nervous system enervates a _____ directly.
gland
What happens when a hormone binds to a receptor?
the signal gets transduced from the hormone to a change in protein activity in the cell.
the adrenal gland sits on top of the kidneys and releases epinephrine in response to signals from the sympathetic nervous system is an example of what pattern of release
the 2nd variation:
nervous system enervates a gland directly.
What 3 things can happen to the Hormone after It is Released?
- Binds to a receptor
- Excretion in the urine.
3.broken down by enzymes (inactivated by metabolism).
Where are intracellular receptors located?
the inside of cells in the cytoplasm
What must hormones be capable of doing to bind to intracellular receptors?
diffuse through the plasma membrane of the cell
T OR F There are three basic classes of hormones?
TRUE
What two hormones can diffuse through the membrane and bind to intracellular receptors?
Steroid and thyroid hormones
what are the basic classes of hormones (3)?
- Peptides
- Amines
- Steroids
T OR F
Peptide hormones as their name implies are large proteins that constitute the majority of hormones.
FALSE,
Peptide hormones are SMALL PROTEINS (peptides)
Place the following steps in order
hormone-receptor complex moves into the nucleus
initiation or inhibition of gene transcription.
protein activity in the cell changes
a hormone-receptor complex is formed
hormone-receptor complex binds to DNA
- a hormone-receptor complex is formed
- hormone-receptor complex moves into the nucleus
- hormone-receptor complex binds to DNA
- initiation or inhibition of gene transcription.
- protein activity in the cell changes
the releasing hormones, oxytocin, many GI hormones, and insulin are an example of which class of hormones?
Peptides
which class of hormones are often released form the cell in an inactive form called a prohormone?
Peptide hormones
When does activation occur in peptide hormones?
when the enzyme causes change in overall shape of the hormone to match receptor.
T OR F
Rarely can peptide hormones be the same molecules as a neurotransmitter.
FALSE, they are OFTEN the same molecule as a neurotransmitter
The molecule is called a hormone if it is released from an __________ gland.
endocrine gland
The 1ST type of amines are the _____________ which include epinephrine, norepinephrine, and dopamine.
catecholamines
which class of hormones are released from actual or modified neural tissue such as the adrenal glands and often play important roles in behavior and stress responses.
amines
Where are membrane-bound receptors found?
on the surface of the cell
The 2ND type of amines are the __________ hormones which contain iodine and affect almost every cell in the body via effects on metabolism.
thyroid hormones
What 3 hormones can bind to membrane-bound receptors?
- Peptide hormones
- catecholamines
- steroid hormones (sometimes)
Which class of hormones are lipophilic molecules?
steroids
What do the hormone-receptor complexes in membrane-bound receptors trigger?
second messenger systems
lipophilic molecules such as steroids contain how many carbon rings?
4
What are the possible effects of triggering second messenger systems that affect protein activity in the cell?
- opening or closing ion channels in the membrane
- enzyme activity in the cell
Many steroids are produced by what?
placenta, gonads, and adrenal cortex
which class of hormones includes testosterone, estrogen, progesterone, cortisol, and aldosterone?
steroids
T OR F
The precursor molecule for all steroid hormones is cholesterol.
true
