Endocrine System Flashcards
(29 cards)
List the major endocrine organs
Pituitary gland
Pineal gland
Thymus
Thyroid gland
Adrenal gland
Pancreas
Ovary/ Testes
Describe endocrine signalling
Relatively slow
Long distance signalling
Unspecific- any cell expressing receptor is excited
Describe paracrine signalling
Local signalling
Fundamental to synapic transmission
Describe autocrine signalling
Cells influence their own activity- released signalling molecule acts on same cell that releases it
Involved in infection immunity
Describe neuroscience signalling
Hypothalamus projects hormones to pituitary
Once acted on pituatary gland, they are released into blood stream and transported to the rest of the body
List the places in the body that peptide hormones are synthesised
Anterior pitatary
Pancreas
Heart
Adipose tissue
Describe the synthesis of peptide hormones
Messenger RNA is triggered which promoted transcription and production of peptide hormones
What do parathyroid hormones do?
Regulate calcium levels to promote bone remodelling
List the amine hormones
- Thyroxine
- Thyrosine
- Epinephrine (Adrenaline)
What are steroid hormones?
Synthesised from cholesterol, therefore they are lipid soluble
Receptors located intracellularly
Outline the metabolism of hormone
Hormones circulate either bound to a carrier protein or ‘free’
Free hormone concentration dictates availability
Bound hormone increases half life
Free hormone concentration dictates physiological response
Kidney/Liver primary sites of hormone catabolism
Target cell also breaks down hormone
List the factors that influence the release of growth hormone
Growth hormone releasing factor
Gherlin
Hypoglycaemia
Starvation
Dec blood fatty acids
List the factors that inhibit growth hormone release
Hyperglycaemia
High levels of fatty acids
Outline the mechanism of action of growth hormone
- Growth hormone binds to growth hormone receptor called JAK2
- This triggers signal transducer ad activator of transcription (STAT)
- STAT complexes translocate the nucleus of a cell
- This includes gene transcription
- Synthesis of insulin- like growth factors are triggered
- Long- term physiological response is modulated
What are the targets and acute effect of growth hormone
Muscle- dec glucose uptake
Fat- inc lipolysis
Liver- inc gluconeogenesis
AKA- Anti-insulin effects
How is growth hormone switched off?
Through negative feedback mechanism
How does thyroid stimulating hormone work?
- Low levels of through hormones in blood/ low stability rate stimulate the release of TRH
- TRH i carried to anterior pituitary,which stimulates the release of TSH
- TSH stimulates thyroid follicular cells
- Thyroid hormones released into blood by follicular cells
- Elevated level of thyroid hormones inhibits release of TRH (-ve feedback)
What is the effect of thyroid hormones on their target cells?
Triggers transcription factor in nucleus and TH receptor in mitochondria
Protein synthesis makes structural proteins/ enzymes which triggers the target cell response
The mitochondria elevate ATP production which also causes a target cell response
Give 3 physiological outcomes of thyroid hormones
Inc basal metabolic rate
Stimulate synthesis of Na+/ K+ ATPase
Stimulate protein synthesis
Outline the hypothalamic response to prolonged forms of stress
Hypothalamus responds to the stress by sending signals to the anterior pituitary gland
End result= cortisol released from adrenal cortex (outer region of adrenal gland)
What are the physiological effects cortisol release?
Liver- Promotes gluconeogenesis
Skeletal muscle- Inhibits glucose uptake, promotes proteolysis of muscle proteins, AA production used by liver for gluconeogenesis
Adipose tissue- Inhibits glucose uptake, promotes lipolysis, FFA’s used by liver for gluconeogenesis
Parturition- Elevated levels just prior to birth enhance oxytocin synthesis and prostaglandin production promote uterine contraction
Anti-inflammatory and Immunosuppressive effects
What is Cushing’s syndrome?
Obesity and weight gain
Resulting from excessive cortisol production
Caused by tumours of adrenal/ pituitary gland
Summarise the effect of adrenaline/ noradrenaline
Increased Field of Vision and mental alertness Increased use of energy by cells
Mobilisation of glycogen and lipid reserves Redistribution of blood flow
Reduced digestion and urine production
Increased heart rate and respiration
Increased sweat gland secretion
When is the release of insulin stimulated?
Inc of blood glucose
Inc of amino acid levels
Inc hormone level (gastrin, secretin and CCK)
