PNB Exam 4 (2nd set of videos)

what is the endocrine system responsible for

responsible for producing the body's hormones

- chemical messenger system within the body

what is endocrine tissue

type of epithelial tissue that is organized into glands

where do endocrine glands release things and what do they release

endocrine glands release secretions into nearby blood vessels

why is placing secretions into the bloodstream important

allows the endocrine system to be very decentralized

ex: in contrast to CNS which is contained in just brain and spinal cord, endocrine glands can be located anywhere inside the body

what causes the endocrine glands to be decentralized

chemical messengers are released into the blood stream so they can go anywhere the blood goes

what does decentralization do to hormones

causes hormones to have a very global affect

- affects tissues in many different places inside the body all at the exact same time

the endocrine system coordinates many processes within the body by ...

effecting changes at the cellular level

what are the 3 main differences between the endocrine system and the nervous system

- NS is one cell to one cell while ES is one cell to many cells

- NS has cells with Gener localized signals while ES has a global affect

- NS has short duration, rapid recovery while ES has long duration long recovery

why is the NS faster than the ES

- NS is based on electricity

why is the ES slower working than NS (3 steps)

- chemical messengers in ES are synthesized and take time to do so

- need to then get released by blood stream and find target tissue which also takes time

- target tissue has to mount some kind of response to the hormone which takes time

the ES is slower compared to NS but is it actually slow

no: still incredibly fast just not electrical

what are tissues that work for the NS and the ES

neuroendocrine tissues

ex: chromaffin cells of the adrenal medulla or hypothalamus

what do neuroendocrine tissues take place of

take the place of post ganglionic sympathetic neurons

- stimulated by sympathetic preganglionic neurons but release hormones into blood stream instead of onto another neuron

5 responsibilities of the endocrine system (responsibilities of the hormones)

- metabolism

- vascular function

- reproduction

- cell growth & cell differentiation

- behavior

how does the endocrine system control metabolism

regulates metabolism by controlling breakdown of fats and release of glucose

what does it mean that the endocrine system controls vascular function

increases or decreases heart rate

why is the endocrine system helpful for cancer biologists

hormones can drive cell growth and cell proliferation

what can cause cancer from the endocrine system

when the endocrine system gets mis regulated it can lead to diseases like cancer

around how many hormones are there inside the body

over 50 closer to 500 (many more to discover or assign functions to)

what are the 3 things that hormones vary in

- origin

- structure

- function

what are the 3 groups of hormones

- peptide

- steroid

- amine

what is the synthesis and storage of peptide hormones

made in advanced and stored in secretory vesicles

how are peptide hormones released from the parent cell

exocytosis

how are peptide hormones transported in blood

dissolve in blood

what is the half-life of peptide hormones

short

where is the location of the receptor of peptide hormones

cell membrane

what is the response to receptor-ligand binding for peptide hormones

activation of second messenger systems; may activate genes

what is the general target response of peptide hormones

modification of existing proteins and induction of new protein synthesis

what are 2 examples of peptide hormones

- insulin

- parathyroid hormone

what is the synthesis and storage of steroid hormones

synthesized on demand from precursors

how are steroid hormones released from the parent cell

simple diffusion

how are steroid hormones transported in blood

bound to carrier proteins

what is the half life of steroid hormones

long

where is the location of the receptor of steroid hormones

cytoplasm or nucleus; some have membrane receptors also

what is the response to receptor ligand binding for steroid hormones

activation of genes for transcription and translation; may have nongenomic actions

what is the general target response of steroid hormones

induction of new protein synthesis

what are 3 examples of steroid hormones

- estrogen

- androgens

- cortisol

what are the two types of tyrosine derivatives

catecholamine and thyroid hormones

what is the synthesis and storage of catecholamines

made in advanced, stores in secretory vesicles

how are catecholamines released from the parent cell

exocytosis

how are catecholamines transported in blood

dissolved in plasma

what is the half-life of catecholamines

short

where is the location of the receptor of catecholamines

cell membrane

what is the response to receptor ligand binding for catecholamines

activation of second messenger systems

what is the general target response of catecholamines

modification of existing proteins

what are 2 examples of catecholamines

- epinephrine

- norepinephrine

what is the synthesis and storage of thyroid hormones

made in advanced; precursor stored in secretory vesicles

how are thyroid hormones released from the parent cell

simple diffusion

how are thyroid hormones transported in blood

bound to carrier proteins

what is the half-life of thyroid hormones

long

where is the location of the receptors for thyroid hormones

nucleus

what is the response to receptor ligand binding for thyroid hormones

activation of genes for transcription and translation

what is the general target response for thyroid hormones

induction of new protein synthesis

what is an example of a thyroid hormone

Thyroxine (T4)

what are peptides

proteins or chains of amino acids

why are peptide hormones so common

peptide hormones are genetically encoded meaning they are produced in the body from genes being transcribed and translated

why does protein translation happens continuously

in order to make sure that these hormones aren't active all the time inside the body

what form are peptide hormones translated in

inactive form

what happens to peptide hormones as they move away from translation machinery and the ribosome

get packaged into vesicles, in a way that makes them a little more active

- process involves cleaving, cutting, and chopping them into smaller pieces

what is the state of an inactive hormone called for peptide hormones

pre pro hormone

how do pre pro hormones become prohormones

cells use proteolytic enzymes

- enzymes that break peptide bonds to produce smaller but still inactive intermediates

what happens to pro hormones

they can then be further cut to produce an active hormone

explain insulin process becoming prepro insulin

- insulin is encoded by the insulin gene and synthesized as pre pro insulin

what are the 3 aspects of pre pro insulin

- pre pro insulin contains 3 regions: signal sequence, b chain, c chain

explain insulin pre pro hormone becoming pro hormone

- prepro insulin gets processed by ER and that results in a signal sequence getting cut off which causes pro insulin formation

explain insulin pro hormone becoming active

- then it gets sent to the Golgi complex

- more processing if more amino acids are removed

- active insulin (goes on to regulate glucose levels)

peptide hormones are synthesized as

preprohormones

preprohormones are the processed to become

prohormones

prohormones are cleaved to become

hormones

the active form of insulin is

small: only has about 50 or so amino acids

(fairly easy to produce)

what are steroid hormones based off of

cholesterol backbone

what makes steroid hormones unique from one another

the side chains or R groups

- some have hydroxyl groups or Quito groups in various positions

what does the backbone of steroid hormones contain

4 hydrocarbon rings

sex hormones are a type of __ hormone

steroid

2 examples of sex hormones

estrogen and testosterone

the hormones of cortical region of adrenal gland (known as cortical hormones) are what type of hormone

steroid

ex: cortisol or aldosterone (in renal system)

what is needed in order to create different side chains

endocrine cells require specific enzymes to catalyze those reactions

making steroid hormones is essentially ...

a complicated stepwise synthesis reaction

2 most important aspects to know about steroid hormones

- process is complicated

- starts from cholesterol back bone

cellular enzymes modify cholesterol to produce ...

different biological active hormones

- enzymes make modifications

___ are just as important as the cholesterol for making the hormones

enzymes

what can testosterone be converted into

hormone called DHT: dihydrotestosterone

- does so by using an enzyme called 5 Alpha reductase

are testosterone and DHT very different

even though these two hormones are structurally very similar, their small differences in structure give them drastically different functions in the body

what are the differences in functions between testosterone and DHT

testosterone: drives the expression of some secondary sex characteristics

- when testosterone turns into DHT: leads to things like male patterned baldness

what do anti hair loss medications inhibit

inhibit alpha5 reductase to block the conversion of testosterone into DHT

what are amine hormones derived from

single amino acids

what are the two single amino acids that amine hormones are based off of

- tyrosine

- tryptophan

which of the two single amino acids that amine hormones are based off of make the hormones that we will talk about

tyrosine

what does tyrosine create

epinephrine and norepinephrine

- also makes neurotransmitter dopamine and thyroid hormones

what is tryptophan used by and what does it do

pineal gland and epithalamus

- produces the hormone melatonin responsible for sleep wake cycle

what can melatonin go on to produce

serotonin

what is common misconception about tryptophan

eating foods high in tryptophan can make you sleepy

- actually, because blood is being redirected from brain to gut

what is something that all hormones have in common

all hormones require receptors in order to work

what are hormones also known as .. which do what

first messengers: get released into blood stream and get distributed throughout the entire body

almost all tissues will get exposed to any given hormone that is in circulation but ...

but only certain tissues respond because only certain tissues have those specific receptors

how can we control the response to a hormone by

controlling the receptor itself

what is receptor upregulation

when a tissue places more receptors on the cell surface for a particular hormone which increases the sensitivity to a hormone

what is receptor downregulation

cell removes receptors from the plasma membrane which decreases the sensitivity to a hormone

not only can we control the level of the hormone ...

we can also regulate the receptor as well

what is a super important fact about receptors and the relationship with hormones when drug or abnormalities are present

even though the hormones can stimulate the receptor it might be unable to respond to signals being sent by the alpha motor neuron