Endocrine Pathophysiology Flashcards
Hormone Regulation
Chemical triggers
Endocrine factors
Neural control
Hormone Regulation - Chemical triggers
Blood sugar levels (if high release insulin, if low release glucagon) Calcium levels (parathyroid hormone especially - if fall too low is released)
Hormone Regulation - Endocrine factors
Hormone from one gland triggers another gland to release a hormone
Ex = Pit gland - TSH - activates thyroid gland to release T3/T4
Hormone Regulation - Neural control
Autonomic nervous system
Startled - SNS activation - hypopituitary axis says need to release adrenal hormones to adapt to stress
Hormone regulation - Neural control
Epinephrine vs. Cortisol
Epinephrine - triggered with F/F
Cortisol - also released by SNS but is more dominant in chronic stress
Initial response = protective = Epinephrine
Longer we are exposed to chronic stress = cortisol levels go up = higher risk of immune suppression
Mechanisms of hormone action
Feedback loops
Hormone receptors
Up regulation
Down regulation
Mechanisms of hormone action - Feedback loop examples with pathology
Hyper or hypothyroid issues have disruption in the feedback loops
Mechanisms of hormone action - Feedback loop examples with pathology - Hyperthyroidism
Hyper - body forms antibodies that mimic TSH - these antibodies attach to TSH receptors on thyroid and thyroid thinks it needs to kick out more T3 and T4 so it will - pit gland senses the extra T3 and T4 so it will dec TSH
So Graves for ex - High T3 and T4, Low TSH
Mechanisms of hormone action - Feedback loop examples with pathology - Hypothyroidism
Thyroid is being attacked by antibodies that kill the thyroid gland and it cannot produce - leaking out as much T3 and T4 as it can - Pituitary thinks we need more TSH so it sends a lot of TSH - Thyroid keeps trying to respond but it can’t
Hashimoto - Low T3 and T4, High TSH
Mechanisms of hormone action - Up regulation
Addition of hormone receptors to a cell membrane - would happen if certain hormones are low in blood and cells are trying to open as many receptors as they can to bring the hormone in
Mechanisms of hormone action - Down regulation
More common in pathology is down regulation
Closing or removal of receptors from a cell
When there is an excess of a hormone in the blood - they say no thank you and close their doors
Mechanisms of hormone action - Down regulation - Example of pathology
Type II diabetes
Person has high glucose levels - body normally responds with secretion of insulin - over time you get hyper insulinemia - chronic high insulin in blood so then your cells down regulate insulin (dec insulin sensitivity)
exercise can restore and reverse this!!! Metformin is common rx
Hypothalamic Pituitary System
Interaction between neurological and endocrine system
Hypothalamus is connected to the pituitary gland
Hypothalamus synthesizes and releases hormones that regulate other glands
Interaction between neurological and endocrine system
Hypothalamic pituitary system
Anterior and posterior pituitary secrete
Different hormones and have differing target tissues
ADH is secreted from anterior or posterior
pituitary
What is other name for ADH
Posterior
Vasopressin
Posterior pituitary - SIADH is what
High levels of ADH
Syndrome of inappropriate ADH
Posterior pituitary - what does ADH normally do
Targets the kidneys and tells them to keep some water stored back in the body
Retain fluid
Posterior pituitary - SIADH - Causes
Ectopic production by tumor (infection/lesion)
Brain injury (impact to pit)
Drugs (barbituates, nicotine, morphine)
Posterior pituitary - SIADH - s/s
Edema, concentrated urine, Hypertension
GH is secreted from anterior or posterior pituitary
Anterior
Hypopituitarism is what
Hypo pituitary condition where you are not secreting enough of a lot of different hormones
GH is usually what we see though
Hypopituitarism - Dwarfism
What is it? Primary cause?
Too little GH
Primary cause is pituitary infarct
GH targets what
muscle and bone
Presentation of hypopituitarism
Presentation depends on which hormone are affected
If GH affected - will see dwarfism
Hyperpituitarism - Gigantism and Acromegaly
Increase in release of GH