Hormones 1

Define Hormones

chemicals seriated by cells in certain parts of the body, that travel through the blood stream to act on a target area in body

Endocrine glands

system of glands that release hormones

Are other parts of the body able to produce release hormones aside from glands

yes there are tissues in the body and organs like the heart which make secrete hormones of their own

Exocrine glands

glands that release fluids with hormones outside of the body like tears, sweat

how is the range of effect, duration of effect for a NT different from a hormone

a NT has a local effect: only within synaptic cleft and allows communication only between involved cells

fast and short lived since it attaches for milliseconds is released and promptly broken down, reabsorbed

what is the range of effect for a hormone

a hormone can several targets, even far away as it travels through the bloodstream so it has a Systemic effect

compared to NT the effect is slow and long lasting since it can work up to seconds or hours, or result in permenent effects that last over time. since it helps with processes like growth, metabolism, stress response.

why does route of transmission: change whether chemicals are NT or hormone

even if the chemical has the same target

ex.

if its norepinephrine released at heart (local effect)

adrenal gland released into blood stream acts on several areas of body to regulate stress response

Major Endocrine Glands

(brain (5), neck (1), adrenal (3), gut (2), genitals (1)

Hypothalamus

Pineal gland

Pituitary gland

Anterior and Posterior pituitary

Thyroid

Adrenal gland, cortex, medulla

Pancreas

Gut

Gonads

Hypothalamus

control center for hormones,

works closely with pituitary glands

Pineal gland

related to melatonin

Adrenal Gland (2 parts)

adrenal cortex: makes glucocorticoids (corisol) - outer

adrenal medulla: makes epineprhine, norepinephrine - inner

Pancreas

related to metabolizing glucose into insulin and glucagon

Gut

related to digestive hormones

Gonads

Endocrine communication

hormone travels through bloodstream to acting on target tissues

endocrine commination with Vasopressin

this chemical is secreted by Pituiary into the bloodstrem where it acts on the Kidneys making it retain water and blood pressure'

in the brain it affect social behaviours

endocrine communication with Cortisol

this chemical when released by the adrenal gland will travel through bloodstream and increase blood glucose, suppress unneeded functions to prepare for stress response.

in the brain it memory, attention

Paracrine comminication

short distance communication where chemical affects nearby cells aka local action

ex Nitric oxide and Histamine

Nitric oxide Paracrine communication

this gas NT diffuses to closeby neurons: and monitors glial cells, causing local vasodilation in active brain regions and, suppresses NTs

Histamine Paracine comminication

mast cells in connective tissue secrete this chemical and it diffuses to nearby blood vessels and vasodilates / increase blood flow there

is Neurotransmission Paracrine or Endocrine

Neurotransmission (NT communication) is paracrine since its local

(hormones are also endocrine only since bloodstream system travel not local)

What is Synaptic Neurocrine communication

communication specifically between NT going to Postsynaptic membrane

(ex. Ach to nicotinic receptros)

Autocrine communication

when a released chemical acts on the cell it was released by (loop where the cell affects its own activity)

ex. Dopaminergic neurons, T lymphocytes

Autocrine commication with Dopaminergic neurons

these neurons release dopamine

dopamine binds to (auto)receptors of same dopaminergic neurons

this regulates dopamine release preventing more

What are the chemicals that are released into the environment for commination

Pheromones

Allomones, kairomones, synomones

Pheromones

chemicals that are released out to commutate with those of same species

what’s being commutated is a standardized message: single interpretation specific (mating, call for danger, destination)

common seen in insects not humans

benefits sender and receiver

Allomones, Allomones, kairomones, synomones

chemicals released into environment to communicate with another species

can be used to repel (defense), or attract

only benefits the sender (luring someone to eat them, or skunk spray to repel)

Allomones

when chemical released to other species only benefits the sender

(luring someone to eat them, or skunk spray to repel)

Kairomones

when chemical released to other species it benefits the receiver

ex. prey naturally gives signal/smell and other predator species can find and eat them (not on purpose)

Synomones

when the chemical released to another species benefits both the sender and the receiver (reciprocal relationship)

ex. bee and flower pollen. smell attracts bee, bee gets pollen for honey and spreads pollen helping flowers

Rooster endocrine hormone experiment

Berthold castrated roosters saw they didn’t develop as well (without testerone)

he put testes back in roosters body at different location before dev and they then had development

not related to nerve connection since its elsewhere so he concluded it must be chemical which is was

(testerone produced in testes was released into bloodstream and is key affector in male development)

Organization effects

these effects are the permeant changes in the body and brain structure due to hormone exposure at early development

ex. in rooster experiment the testes had to be implanted back during early development otherwise no regular organizational effect where rooster developed male characteristics from testerone

Activational effects

hormones which when given to adults activate behavior but are temporary and not as dramatic as organization effect

(most hormones)

ex. testosterone while has organizational effect also increases sexual behavior

Principles of Hormone Action pt. 1 (GCRM)

Gradual

Changes probability or intensity of behavior

Reciprocal relation behavior

Multiplicity of action

Gradual (hormone effect)

hormones take hours or weeks to create physiological or behavioral response once it enters bloodstream

the change after the hormone can last over time (days, weeks, years)

hormones Change probability ort intensity of behavior

when you give a hormone it changes how the behavior happens or the context the behavior happens. 

sometimes stronger than intended. predicts behavior will be more intense, likely to happen

(doesnt create a behaviour just affects likelihood, intensity)

what is meant by hormones have a Reciprocal relationship with behavior

hormones increase behaviors and behaviour also increases the release of hormones

during fight, testoterone increase and this increases agressive behaviour

what is meant by hormones have Multiplicity of action

hormones can have multiple effects (since they travel throughout body, widespread effect they can effect several areas, different hormones at same time)

so the resulting behavior may be influenced by several hormones

Principles of Hormone Action pt. 2

Pulsatile secretion pattern

Rhythmic changes

Can interact with other hormones

Cells with a receptor protein for that hormone

Pulsatile secretion pattern (hormones)

hormones are secreted in bursts or pulses (starting and stopping)

(hormones have) Rhythmic changes

hormone pulses is rhythmic and changes throughout day usually influenced by circadian rhythm

when there’s a hormone imbalance and hormone has to be artificially given its an issue since its difficult to follow natural pulses.

(ex.1 diabetes, insulin injections doesn’t completely mimic body)

(hormones) Can interact with other hormones

when hormones interact with other hormones it can change their effects

(cortisol wants to increase energy to respond to stress affecting glucagon and insulin which control energy consumption)

cells with a receptor protein for that hormone

hormones will only act when there is a receptor for them. important since hormoens would just act everywhere with receptors for specifc hormone they will only act where needed

Neuroendocrine cells

neuron (cells)in the hypothalamus that release hormones straight into the bloodstream

they are important since they bridge the nervous system (brain) and endocrine system (bloodstream)

how do Neuroendocrine cells work

neuroendocrine cell gets impulse, has vesicles which release hormones which diffuse into nearby blood vessels and thus move into the blood

Neuropeptides

complex proteins that are used by neurons to change the sensitivity for receptor binding (acts as a neuromodulator)

Neuromodulators

changes the sensitivity of cell receptors to regulate the activity of certain transmitters

(works more slowly than neurotransmitters and has longer effects)

3 types of hormones by chemical structure

Peptides

Amines

Steroids

why si the chemical structure of a hormone relevant?

the chemical structure of a hormone is tied to where they act within a cell

Peptides

short strings of amino acid (protein building blocks). they are water soluble so cannot enter cell membran

Amines

modified single amino acids

water soluble cannot enter cells other than thyroid hormones

so need receptors outside of cell to attach/ carry out function

Steroid

4 rings of carbon atoms (derived from cholesterol)

sex hormones, glucocorticoids

they can enter the cell since they are lipid based and lipid soluble can bypass bilipid membrane.

binds to receptors inside the cell

can change function of cell itself by going inside

how do different hormones bind to receptors trigger change

binds the same way as NT: lock and key

they act fast (for hormones) seconds to minutes

Peptides and Amines bind to exterior receptor: triggering second messenger pathways leading to alteration

Steroid binds go inside cell and bind to receptor

what is the process of binding on exterior G coupled receptors for hormones

Peptide and amine hormones bind on exterior G coupled receptors (most are), causing them to change shape

the G protein subunits spilt and activate second messenger can trigger various pathways

cyclic AMP

a second messenger used in hormone activated G protein coupling.

it transmits the messages of defense hormones and can have different effects depending on type of cell, cell activity, cell’s location)

whats the process of Steroid hormone binding

1. acts slowly (hrs) to diffuse past call membrane and reach the receptors inside their target cells.

2. when binded to steroid receptor it forms a steroid-receptor complex

3. steroid receptor complex goes inside nucleus binds to DNA

4. becomes a factor in transcription: and alters gene expression

5. leading to production of a new protein that has changes the cells leading to biological effects (organizational effects)
   

what are cofactors to know for Steroid-receptors complexes

enhances or suppresses the effects of steroids in the cell: (works on specific cells) leading to the steroid hormone having a very stron effect or weak effect (depending on the cofactor)

Cell may respond

Different coactivators

same hormone different effects

why may the cell need to respond to Steroid receptor complexes

May be necessary for the cell to respond to the steroid-receptor complexes

why do different cells have different types of coactivators (Steroid-receptor)

Different cells can have different types of coactivators.

The same hormone can cause different effects in different cells, depending on which
coactivators are present

Genomic effects

an gene/protein altering effect from when steroid or thyroid hormones attach to intercellular receptor and alter gene transcription changing the protein being synthesized

slow and can takes hours

Non-genomic effects

an effect that does not directly alter gene expression.is produced by hormones attaching ot membrane receptors

has a rapid response