Lecture 7 - Pituitary physiology Flashcards
Pituitary effect loops: what is the standard loop and how do the latter stages affect the prior ones?
Hypothalamus - pituitary - effector gland
Produced effector hormone suppresses prior organs through a negative feedback loop
How can we use hypothalamus/pituitary gland hormone levels to locate problems within the endocrine systems?
Compare hypothalamus and pituitary gland hormones to figure out what the issue is - ie high amounts of gland while pituitary is low (suppressed by negative feedback) then it is likely to be a gland issue
Pituitary gland: what is it important for?
- Metabolic control
- Sexual function
- Fertility
- Puberty
- Water balance
- Stress response
- Growth
- Lactation
- Parturition (childbirth)
Pituitary gland: what are the components of it and do they differ in how they receive signals?
- Anterior - signals from H through the blood
- Posterior - neuronal signals from H
- Pituitary stalk
Optic chiasm: what is it and what clinical significance can it have with the pituitary gland?
Space just above the pituitary gland where the optic nerves cross over and where a pituitary tumour may invade, potentially causing a loss of vision
Anterior pituitary axes: what are they?
- Growth
- Adrenal
- Gonads
- Thyroid
- Prolactin
Posterior pituitary hormones
Vasopressin, oxytocin
(rewatch)
Growth hormone system: what is the hypothalamic signal, what is the pituitary hormone, what is the target organ, and what is the downstream hormone?
Growth hormone releasing hormone (GHRH)
Growth hormone (GH)
Liver
Insulin-like growth factor-1 (IGF-1), resulting in growth
Adrenal hormone system: what is the hypothalamic signal, what is the pituitary hormone, what is the target organ, and what is the downstream hormone?
Corticotropin releasing hormone (CRH)
Adrenocorticotropin hormone (ACTH)
Adrenal cortex
Cortisol
Gonad hormone system: what is the hypothalamic signal, what is the pituitary hormone, what is the target organ, and what is the downstream hormone?
Gonadotrophin releasing hormone (GnRH)
LH/FSH
Gonads
Testosterone/oestrogen
Thyroid hormone system: what is the hypothalamic signal, what is the pituitary hormone, what is the target organ, and what is the downstream hormone?
Thyrotropin releasing hormone (TRH)
Thyroid stimulating hormone (TSH)
Thyroid
T4 (T3)
Prolactin hormone system: what is the hypothalamic signal, what is the pituitary hormone, and what is the target organ?
Dopamine, neuropeptides
Prolactin
Mammary gland
Vasopressin: what is it, when is it released, and what does it do?
Anti-diuretic hormone (ADH)
Controlled by baroreceptors and osmoreceptors
Regulates water reabsorption in the kidney
Oxytocin: what is it and what does it do?
Critical hormone in the processes of parturition and lactation and also social behaviours (notably bonding)
Overactive thyroid: what are the key symptoms?
- High temps
- Quick metabolism
- Weight loss
- High bone turnover
- High heart rate
- Fast growth/puberty
Underactive thyroid: what are the key symptoms?
- Low temps
- Slow metabolism
- Weight gain
- Slow bone turnover
- Slow heart rate
Adenohypophysis: what is it?
AKA anterior pituitary - front lobe of the pituitary gland
Syndrome: what is it?
Group of symptoms which consistently occur together, or a condition characterized by a set of associated symptoms
FIPA: what is it and what does it mean?
Familial-isolated pituitary adenomas - pituitary tumours that are not associated with any other tumours
A patient complains of weight loss and sweating and has the following blood test, what is their diagnosis:
TSH - low
fT4 - high
fT3 - high
Primary hyperthyroidism - inappropriate production of thyroid hormones which is likely to also be causing negative feedback onto TSH
A patient complains of weight loss and sweating and has the following blood test, what is their diagnosis:
TSH - slightly high
fT4 - high
fT3 - high
Secondary hyperthyroidism - inappropriate production of TSH which is likely to be causing high production of thyroid hormones, suggesting a pituitary issue
A patient complains of weight gain and coldness and has the following blood test, what is their diagnosis:
TSH - high
fT4 - normal
fT3 - low
Primary hypothyroidism - under-production of thyroid hormones which is likely to be caused by the thyroid becoming unresponsive to TSH despite the high levels
A patient complains of weight gain and coldness and has the following blood test, what is their diagnosis:
TSH - low
fT4 - low
fT3 - low
Secondary hypothyroidism - under-production of thyroid hormones which seems to be caused by the under-production of TSH, suggesting a pituitary issue
