Endocrine Flashcards
What does the endocrine system do?
Secrete hormones from glands to act on target cells
What is neurocrine? Why would you not just use nervous system?
Neurons secreting hormones into blood to target cell that doesn’t have neuroreceptors
Give three areas of the body where there is neurocrine communication
Adrenal Medulla
Ant Pituitary
Post pituitary
There are 9 major glands name them
Hypothalamus Pituitary Thymus Pineal Gonads Thyroid Parathyroid Adrenals Pancreas
Hormones can act on target to cells to control what 5 things?
1) Reproduction
2) Metabolism
3) Growth
4) Body Defence
5) Homeostasis - fluid/electrolyte balance of blood
What is the role of the Thymus? Using what hormone? What happens in adolescence?
Maturation of bone derived stem cells to mature T cells - using Thymosin. Involutes in teens to mostly fat.
What is another way of saying T cell maturation
Thymic Cell Education
What is the HPA Axis? Give an example of what it is used for and state how.
Hypothalamic-pituitary-adrenal axis. Used in stress response
Hyp neurones produce CRH - enters hypothalami-hypophyseal circuit to ant pit
Ant pit produces ACTH - endocrine travel in blood to adrenal gland - adrenal produces cortisol.
Which gland is central to homeostasis?
Hypothalamus
Hypothalamus controls loads of things name 5
Hunger Sexual behaviour Thermoregulation Stress response Lactation Heart rate/BP Circadian rhythm Autonomic input
Name 2 hormone that are produced by hypothalamus and travel to POST pituitary
There are 6 others - name 2 released from ANT pituitary
Oxytocin
ADH
TSH
ACTH
Hypothalamus is both nervous and endocrine true or false
true
What is a portal system? Where can you find two in the body?
2 capillary beds in series
Portal-hepatic
Hypothalamo-hypophyseal
What is the HPT axis and what happens? What are the two feedback loops?
Hypothalamic-pituitary-thyroid axis
Hyp neurones produce TRH - travels down neurones enter hypothalamo-hypophyseal circuit to ant pit - ant pit cells produce TSH - travels via blood to thyroid- thyroid produces T3 T4(thyroxine). Thyroxine has negative feedback to the ant pit (short loop) and hyp (long loop)
Give 3 examples where neuroendocrine signalling occurs in the body
HPT axis
HPA axis
Chromaffin cells into blood
What are 2 catecholamines?
Adrenaline and NA
What are chromaffin cells? Where are they found? What do they do?
Modified neurones in adrenal medulla - act as post-ganglionic sympathetic neurones that secrete adrenaline/NA into blood - example of neuroendocrine
The stress response is initiated by 3 systems _______ ________ and _________
Nervous
Endocrine
Immune system
Which type of hormone are slow and long acting? What do they do? Where do they act in the cell? Give some examples
Steroids are slow because they are synthesised on demand from precursors which takes time. They act mostly on cytosol/nucleus, mostly activate transcription/translation (makes sense if act on nucleus). E.g. oestrogen, aldosterone, cortisol
What are the two types of corticosteroids? Where are they made? What is the difference?
Glucocorticoids - more for immune response
Mineralocorticoids - more for electrolyte/water balance
Made in adrenal cortex
Which two types of hormone are carried in the blood by proteins?
Steroids and Thyroid hormones
Which two types hormones are dissolvable in blood?
Glycoproteins and catecholamines
Give two examples of glycoproteins as hormones. Are they fast/slow acting? What happens when they get to the cell (where do they bind what do they do)
Insulin and Glucagon, quite fast mins-hours (think after food). They bind to cell surface receptors and elicit 2nd messenger response.
Which are the two fastest acting groups of hormone? Why?
catecholamines, thyroid hormones. Premade in vesicles ready to go.
Which 3 groups of hormone are premade in vesicles and which 1 is made on demand
Premade vesicles - thyroid, catecholamines, glycoproteins
On demand - steroids
Which two groups of hormones act by activating 2nd messaging systems in cell, and which two act on transcription/translation?
Thyroid and steroid - transcription/translation
Catecholamines/glycoproteins act on 2nd messenger systems
Which two hormones are involved in short term stress response, which two in long term?
Short - NA/Adrenaline
Long - aldosterone and cortisol
What is the short term vs long term stress response?
Short term:
- increase HR, BP, Sweating, reduce digestion, glucagon, increased alertness –> glucose etc
Long term: Aldosterone - increased Na retention, increased BP and blood vol
Cortisol - surpressed immunity, increased blood sugar as protein and fats converted to glucose
What is the typical distance for paracrine communication
20nm
What are 3 groups of paracrine molecules
Ach, Monoamines, amino acids
Is neuron synapse-synapse an example of paracrine?
Yes
Are glutamate glycine and GABA inhibitory or excitatory transmitters in paracrine communication?
Glu +
Gly -
GABA -
How are oxytocin and ADH produced and released?
Produced by hyp neurons, travel to POST pit, then to blood
What is the pineal gland? What does it do? What happens in early adulthood?
Small gland, full function unknown, produces melatonin which is involved in circadian rhythm. Melatonin inhibits release of gonadotrophin (LH and FSH). It calcifies
Name two gonadotrophin and what inhibits their release
LH and FSH
Release inhibited by melatonin that is produced by the pineal gland.
