endocrine system 1 Flashcards
week 1
the endocrine system influences the body’s metabolic activities via —
hormones
the endocrine system’s responses are — but — than those of the nervous system
slower; longer lasting
what is endocrinology?
the study of hormones and the endocrine organs
what five things does the endocrine system control and integrate?
- reproduction
- growth/development
- maintenance of electrolytes, water, nutrient balance
- regulation of cellular metabolism and energy balance
- mobilization of the body’s defenses
exocrine glands produce — and — ducts
non-hormonal substances; have
endocrine glands produce — and — ducts
hormones; lack
nervous system is — duration responses, endocrine system is — duration responses
short; long
neurotransmitters in the nervous system act over — distances, hormones in the endocrine system act over — distances
short; long
what are five types of endocrine glands?
pituitary, thyroid, parathyroid, adrenal, and pineal
the hypothalamus is a — organ
nueroendocrine
the —, —, and — have exocrine and endocrine functions
pancreas, gonads, and placenta
what are hormones?
long-distance chemical signals that travel through blood and lymph
what are autocrines?
chemicals released by a cell that affect the same cell that released them.
what are paracrines?
chemicals released by a cell that affect nearby cells, not the cell that released them.
— and — are not considered part of the endocrine system
autocrines; paracrines
what are three types of amino acid-based hormones?
amino acid derivatives, peptides, and proteins
steroids are made from —
cholesterol
— hormones and — hormones are two types of steroids
gonadal; adrenocortical
what are target cells?
tissues with receptors for a specific hormone
upon arrival at target cells, hormones may be able to alter — and/or — by opening/closing ion channels
plasma membrane permeability; membrane potential
upon arrival at target cells, hormones may be able to stimulate the production of — or —
enzymes; other proteins
upon arrival at target cells, hormones may be able to activate/deactivate —
enzymes
upon arrival at target cells, hormones may be able to trigger/cause —
secretion
upon arrival at target cells, hormones may be able to stimulate —
mitosis
water-soluble hormones are all — hormones except — hormone
amino acid-based; thyroid
lipid-soluble hormones include — and — hormones
steroid; thyroid
water-soluble hormones — directly enter a cell and act on — receptors
cannot; plasma membrane
lipid-soluble hormones — directly enter a cell and act on — receptors
can; intracellular
except for thyroid hormone, amino acid-based hormones exert effects through —
second-messenger system
what are two main second-messenger systems?
- cyclic AMP
- PIP2-Calcium
what are the five steps for activating a second messenger?
- a hormone (first messenger) binds to a receptor.
- the receptor activates a G protein.
- the G protein activates or deactivates the enzyme (adenylate cyclase).
- adenylate cyclase turns ATP into cAMP (second messenger).
- cAMP activates protein kinases, which then modify other proteins to produce responses in the cell.
In the cAMP pathway, G protein activates the enzyme —. In the PIP2-Calcium pathway, G protein activates the enzyme —
adenylate cyclase; phospholipase C
phospholipase C splits membrane protein, PIP2, into two second messengers: — and —
diacylglycerol (DAG); inositol trisphosphate (IP3)
diacylglycerol (DAG) activates — and triggers — within target cells.
protein kinases; cellular responses
Inositol trisphosphate (IP3) causes — to be released from intracellular storage sites.
calcium ions (Ca2+)
freed Ca2+ ions act as a —
second messenger
calcium ions (Ca2+) either alters enzyme and channel activity or binds to a regulatory protein called
calmodulin
what happens when Ca²⁺ binds to calmodulin?
it activates enzymes that amplify the cellular response.
what happens when a lipid soluble hormone enters a cell and where does it go to create change?
it binds to a receptor inside, then goes to the nucleus to control gene activity and make proteins that change the cell’s function.
creation and release of most hormones is regulated by —
negative feedback loops
what is a negative feedback loop?
when the body detects a change and works to REVERSE it, keeping things stable.
example of a negative feedback loop?
when the body gets too hot, it sweats to cool down, bringing the temperature back to normal.
what three ways are endocrine glands stimulated to make and release hormones?
- humoral stimuli
- neural stimuli
- hormonal stimuli
when one hormone triggers the release of another hormone, this is — stimuli
hormonal
when hormones are released due to signals from the nervous system, this is — stimuli
neural
when hormone release is triggered by changes in the levels of certain substances in the blood, this is — stimuli
humoral
what is an example of humoral stimuli?
If blood sugar drops, the pancreas releases glucagon to raise it.
what is an example of neural stimuli?
when you’re scared, your brain sends signals to the adrenal glands to release adrenaline.
what is an example of hormonal stimuli?
the hypothalamus releases a hormone that tells the pituitary gland to release another hormone, which then signals the thyroid to release its hormones.
what is the hypothalamic pituitary target endocrine organ feedback loop
a system where the hypothalamus, pituitary gland, and a target endocrine organ work together to regulate hormone levels in the body.
how does the hypothalamic-pituitary-target organ feedback loop work?
through the release of hormones from the hypothalamus and pituitary gland, which stimulate a target organ to release its hormones. when the target organ’s hormones reach a certain level, negative feedback reduces further hormone production, which keeps the balance.
what does it mean when we say the nervous system can override the endocrine system?
it means the nervous system can send fast signals to change the body’s responses, even if hormones from the endocrine system are already working.
what three factors does target cell activation depend on?
- blood levels of the hormone
- the number of receptors on or in a target cell
- how strongly the hormone binds to the receptor
true or false: multiple hormones can not act on the same target at the same time
false; multiple hormones CAN act on the same target at the same time
what are the three types of interactions between hormones affecting the same target cell?
permissiveness, synergism, and antagonism
which interaction needs one hormone in order for another hormone to work?
permissiveness
which interaction has one hormone that opposes the action of another hormone?
antagonism
which interaction has two hormones that work together to create a stronger effect?
synergism
example of permissiveness?
reproductive hormones need thyroid hormone to have an effect.
example of antagonism?
insulin lowers blood sugar, while glucagon raises it
example of synergism?
glucagon and epinephrine both make the liver release glucose.
