Kin 131 exam Endocrine system Flashcards
What is a hormone?
A chemical messenger that is secreted into the bloodstream to influence another organ or tissue
What is the endocrine system?
A series of glands throughout the body that produce hormones
Explain the differences between the endocrine system and the nervous system
Signalling mechanisme:
- Endocrine: Chemical
- Nervous: Chemical and electrical
Primary chemical signal:
- Endocrine: Hormones
- nervous: Neurotransmitters
Response time:
- Endocrine: Fast or slow depending on where its traveling from
- Nervous: Imediate
Target cell:
Endocrine: near or far
Nervous: Nearby
Environment interaction:
- Endocrine: internal only
- Nervous: Internal and external
What are the different type of endocrine glands?
A gland is a tissue that secretes a substance
Exocrine glands:
- Secretes substance into a duct
Endocrine glands:
- Secretes directly to the bloodstream
What are paracrine and autocrine substances?
paracrine substance:
- Causes a reaction on the cells around it
Autocrine substance:
- Causes a reaction with the cell that released it
What two substances hormones are made of. What are the different ways they are transported
- Lipid based
- Dont need a vesicle to cross the lipid bilayer of the cell since they are lipid soluble, but a carrier protein is needed once in bloodstream - Amino acid based
- Needs a vesicle to cross the lipid bilayer since their not lipid soluble, but does not need a carrier protein to be transported in the bloodstream
Where are the receptor cells located for water soluble hormones vs lipid soluble hormones?
Water soluble
- Receptors on the outside of the lipid bilayer
Lipid soluble
- Receptors on the inside of the lipid bilayer
What are the ways sensitivity to hormones can change
- Up-regulation
- Target cell becomes more sensitive due to the increase in receptor cells caused by low concentration of that hormone - Down regulation
- target cell becomes less sensitive to the hormone, due to lower numbers of the receptor cells caused by excessive amounts of that hormone
What are the different affects hormones can have
- permissive effect:
- Interaction between hormones where one hormones enables the other to work - Synergistic effect:
- interaction where two hormones amplify each others effects - Antagonistic effect
- When two hormones have opposing effects
What are the 3 different ways hormones are triggered to be released
- Plasma ion concentration
- Detecting a change in concentration of a substance triggering the release of hormones - Neuronal controle
- Neurons stimulates the release of a hormone
- Eg. the adrenal medulla - Another hormone
- One hormone triggers the release of another
- Called a tropic hormone
Ways hormones are removed after they complete their function
- Exretion
- Excreted through ruin - Liver metabolization
- Enzymes in the blood breaking them down to amino acids
- Target cells break them down to their amino acids
Which removal is faster? The removal of amino based hormones or steroid based hormones?
Amino acid hormones are removed quickly
Steroid hormones are removed slowly
Explain the Hormone disorders
AT GLAND
1. Hyper secretion: too much hormone is produced
- Primary: Gland just overproduces
- Secondary: Overstimulation
- Hyposecretion: Too little hormone is produced
- Primary: gland just doesn’t produce enough
- Lack or overinhibition of a stimulus
AT TISSUE
1. Hyper responsive: Target tissue has excessive reposes to hormones to to excessive receptors
- Hyporesponsive: Target tissue has no or little reaction to hormone due to loss or dysfunctional receptors
What are the key organs that secrete hormones
- Pineal gland
- Adrenal gland
- Hypothalamus and pitituary gland
- thyroid
- Parathyroid glands
- Pancreas
- Ovaries
- Testes
Explain the Pineal gland.
Location: In the brain inferior to the thalamus
Function: Production and secretion of melatonin
Release controled by: Hypothalamus
Melatonin:
- Controls our circadian rhythm (sleep wake cycle)
- Melatonin causes us to sleep
- Light stimulus inhibits the production of melatonin
Explain the adrenal gland
- Location: sits onto of the kidneys
- Consists of
1. the adrenal cortex (3 zones)
2. Adrenal medula
Explain the adrenal cortex
- Produces steroid based hormones
- Produces long hormones that regulate long term stress and blood pressure
3 zones:
1. Zona glomerulosa: Produces aldosterone: Hormone that regulates water, water, and bloodpressure in body
- Zona faculata: Produces cortisol: helps the body respond to stress by increasing blood sugar and metabolism, and it also has an anti-inflammatory effect.
- Zona reticulairis: Produces androgens: Converted to testosterone and estrogen
Explain the adrenal medulla
- Sympathetic neurons communicate directly with it during stress
- Produces amine based hormones (catacholmeins: Epinephrine and norepinephrine)
- Hormones released due to short term stress