The Endocrine System (Part 1) Flashcards
explain the main functional difference between the endocrine and nervous system
- nervous - rapid response
2. endocrine - slower, more prolonged response
finish the sentence: the endocrine glands and cells release…
the endocrine glands and cells release hormones (chemical substances) into the bloodstream to target specific organs, tissues and cells, and to elicit a response
state 3 functions of the endocrine system (5 available)
- produce hormones
- regulate metabolism
- regulate the balance of ions, water and nutrients in the blood stream
- controls response to stress
- regulates growth, development and reproduction
state what it is meant by the key term - myokines
A myokine is one of several hundred cytokines or other small proteins and proteoglycan peptides that are produced and released by skeletal muscle cells in response to muscular contractions
state what it is meant by the key term - adipokines
cytokines secreted by adipose tissue, and are important regulators of appetite and satiety, energy expenditure, inflammation, blood pressure, etc…
state what it is meant by the key term - hepatokines
any of several cytokines found in the liver
state what it is meant by the key term - endocrine
relating to or denoting glands which secrete hormones or other products directly into the blood
state what it is meant by the key term - exocrine
relating to or denoting glands which secrete their products through ducts opening on to an epithelium rather than directly into the blood
state 3 structural/functional facts about glands
- a single gland may secrete multiple hormones
- usually a gland is composed of different cell types
- a certain cell type within a gland will secrete a specific hormone
state what epinephrine and norepinephrine are
adrenaline (epinephrine) and noradrenaline (norepinephrine)
state the 3 major classes of hormones
- amine hormones
- peptide + protein hormones
- steroid hormones
finish the sentence: the chemical structure of hormones influences…
the chemical structure of hormones influences how hormones are transported in the blood and how they will interact with the target cell (mode of action)
what are amine hormones derived from
Amine hormones are derived from the amino acid Tryosine
state 3 examples of amine hormones
- Thyroid hormones secreted by thyroid glands
- epinephrine and norepinephrine
- dopamine
what are epinephrine, norepinephrine and dopamine collectively known as
catecholamines
state 2 examples of thyroid hormones
- throxine (T4)
2. triiodothymine (T3)
where are epinephrine/norepinephrine secreted by? (2 places)
- adrenal medulla, in adrenal glands
2. adrenergic neurones in nervous system
where is dopamine secreted from?
the hypothalamus
state 3 examples of peptide/protein hormones
- insulin
- glucagon
- insulin-like growth-factor 1 (IGF-1)
- glucagon-like peptide 1 (GLP-1)
- HGH
- Leptin
state 4 facts about peptide/protein hormones
- usually synthesised as protein pro hormones in the endocrine cells
- packaged into secretory vesicles, pro hormones then turned into peptides (active hormones)
- stored inside the cell
- released into bloodstream when cells stimulated
state 3 facts about steroid hormones
- derived from cholesterol (lipid)
- all hydrophobic
- primarily produced in the adrenal cortex and the gonads (testes and ovaries)
what is 1,25-dihydroxyvitamin D
1,25-dihydroxyvitamin D is a steroid hormone secreted by the kidneys
what is the effect of a hormone directly related to
the effect of a hormone is directly related to the concentration of that hormone in the blood stream
the concentration of a hormone in the blood depends on what 4 factors?
- secretion from endocrine cell (stimuli/input dependent)
- metabolism + excretion of hormones
- how they circulate in the blood (free or bound to plasma transport proteins)
- the binding to target cells to illicit a response
state what it is meant by the key term - tropic hormones
hormones which induce the secretion of other hormones are often termed ‘tropic hormones’. usually induce the growth and development of the target cell
state the 2 major factors which determines hormone transport in the blood
depends on their chemical composition and mainly their water solubility (hydrophilicity)
state what it is meant by the key term - hydrophilicity
Having an affinity for water; readily absorbing or dissolving in water
state 4 facts about protein + amine hormone transport in the blood
- usually water soluble to dissolved in plasma
- fact acting
- short half life (minutes)
- rapidly eliminated
state 4 facts about steroid and thyroid hormone transport in the blood
- lipid soluble (hydrophobic) and bind to plasma transport proteins
- slower action
- long half life (hours to days)
- slower elimination
state what it is meant by the key term - blood hormone concentration
the total hormone concentration is the sum of the free and bound hormones, but only free hormones can interact with target cells and organs
state the blood hormone concentration formula
free hormone + carrier plasma protein ->-
what is the concentration of free hormone usually measured in?
low micrograms, nano-grams, or pico-grams
state 3 facts about the mechanisms of hormone action
- carried to all tissues, but only certain tissues respond
- tissue that respond have specific receptor proteins ON or IN the target cell
- the location depends again on the water/lipid solubility of the hormones
state what it is meant by the key term - second messengers
small biologically active molecules which are produced inside the cell as a result of the peptide hormones binding to it’s cell surface and the activation of the signal pathway
state 3 examples of second messengers
- cyclic AMP (cAMP)
- inosine triphosphate (IP3)
- diaglycerol (DAG)
state 2 facts about hormone-receptor interactions
- the number of receptors is essential for the hormones actions on the target cell
- because the number of receptors is limited, the hormones action will always reach a saturation point and plateau
- the number of receptors could be regulated by the availability of the hormone in the blood stream (up + down regulate)
- some hormones can regulate receptors for other hormones too - permissive role
state the names of the 4 types of endocrine disorders
- hypo-secretion
- hyper-secretion
- hyposensitivity
- hypersensitivity
state what it is meant by the key term - hypo-secretion
too little hormone is secreted (eg - type 1 diabetes)
state what it is meant by the key term - hyper-secretion - plus one example
too much hormone is secreted (usually caused by an endocrine tumour; eg - water retention, hyper-secretion of vasopressin/ADH)
state what it is meant by the key term - hyposensitivity plus one example
reduced responsiveness of the target cell to physiological levels of hormone (eg - insulin resistance in type 2 diabetes)
state what it is meant by the key term - hypersensitivity - plus one example
increased responsiveness of the target cell to the hormone (eg - hyperthyroidism causes inc^ HR due to inc^ epinephrine receptor count)
