Endocrine Flashcards
List 4 functions of the endocrine system
Growth & development
Sex differentiation
Metabolism
Adaptation
What is a hormone, and how do they move around the body?
Chemical messengers in body fluids that move through the blood to distant/local target sites
Give an example of a single hormone that exerts effects on multiple tissues
Estradiol
Give & define an example of a single function regulated by several hormones
Lipolysis - release of fatty acid from adipose tissue
List the classes of hormones with examples
Amines e.g. Adrenaline, noradrenaline, T4, T5
Proteins & polypeptides e.g. cortisol, aldosterone, testosterone
Steroids e.g. insulin, growth hormone
Describe how do amine & steroid hormones circulate in the blood
Carried by specific carrier proteins that are synthesised in the liver
Describe how peptide & protein hormones circulate in the blood
Circulate as free, unbound molecules
Describe the different types of receptors that bind to different classes of hormones
Protein & polypeptide hormones bind to cell surface receptors and act through 2nd mechanisms
Steroid hormones bind to receptors inside the cell e.g. cytoplasm/nuclear receptors which modulate protein/enzyme synthesis
Which type of receptor induces a longer duration of action after binding to a hormone?
Receptors inside the cell e.g. nuclear receptors compared to cell-surface receptors due to new DNA produced
Describe 2 factors affecting response of target cell to hormone
No. Of receptors present determines up/down regulation
Affinity of receptors affected by conditions e.g. pH
Describe the MOA of protein & polypeptide hormones binding to receptors
Hormone binds to cell-surface receptors
Initiating transduction
Enzyme activation
Channel opens
2nd messenger system
Protein synthesis
Describe the MOA of steroid hormones binding to receptors
Unbound hormones diffuse into cell cytoplasm/nucleus
Receptor-hormone complex binds to DNA activating/suppressing gene(s)
Transcription creates new mRNA that moves back into cytoplasm
Translation produces new proteins
Some steroid hormones bind to membrane receptors that use 2nd messenger systems to produce a rapid response
What part of the brain coordinates hormone regulation?
Hypothalamus
List 6 hormones involved in hormone regulation
GHRH
TRH
CRH
GnRH
Somatostatin
Dopamine
Describe 3 ways in which hormone levels are monitored
Negative feedback e.g. monitor uptake of insulin & glucagon to maintain homeostasis
Positive feedback e.g. breastfeeding - involves hypothalamic - pituitary target cell system
Level of substance the hormone regulates
