Endocrine Disorders W3 Flashcards
The endocrine system is the body’s main communication system, composed of glands, tissues and organs that release hormones into the blood stream.
How is it linked to the nervous system?
Linked to the N.S by hypothalamus… *Hypothalamic pituitary axis*
Hypothalamus controls pituitary gland, pituitary regulates realease of hormones from other glands
Compare and constrast the N.S and Endocrine system
N.S
- messengers = electrical impulses and neurotransmitters through neurons
- brain and spinal chord
- voluntary and involuntary control
- localised responses, fast, short lived
Endocrine
- messangers = hormones through blood
- glands and organs
- involuntary control
- widespread responses, slow, long lasting
What are the structures of the endocrine system
Glands: pituitary, thyroid, parathyroid, adrenal and pineal glands, thymus, pancreas, gonands
Other tissues and organs: adipocytes, cells in small intestine, stomach, kidneys and heart
What is the control centre of the endocrine system
The hypothalamus realeases hormones which stimulate release of hormones from pituitary
What is the main form of feedback that regulates endocrine hormones
- Negative feedback: keeps concentration of a hormone within relatively narrow range
= maintains homeostasis - Positive feedback: causes concentration of hormone to become increasingly higher: only for oxytocin
Describe how Calcium levels are controlled using negative feedback
Increased Ca2+ in blood
= Thyroid releases calcitonin
= osteoclast inhibited + Ca2+ reabsorbtion by kidneys decreases
= Ca2+ level in blood decreases
Decreased Ca2+ in blood
= Parathyroid releases PTH
= osteoclast reabsorb bone (release Ca2+) + Ca2+ reabsorbed from urine by kidneys and small intestine
= Ca2+ level in blood increases
List and describe the 3 classifications of cause for hypo-/hyper-function
Primary: originate in the gland responsible for producing the hormone ex. tumour
Secondary: defective levels of tthe stimulating hormones or releasing factors but normal gland function ex. GFRH from hypothalamus
Tertiary: result from hypothalamic dysfunction, affecting pituitary function
What hormones are released from the anterior and posterior pituitary?
G - growth hormone (anterior)
O - oxytocin (posterior)
A - antidiuretic hormone (posterior)
T - thyroid stimulating hormone (anterior)
F - follicle stimulating hormone (anterior)
L - luteninsing hormone (anterior)
A - adrenocorticotropic hormone (anterior)
P - prolactin (anterior)
Describe the symptoms and possible causes of Hypopituitarism
Underproduction of hormones released by the pituitary gland
- Usually gradual in appearence of signs
- Symptoms depend on WHICH hormones under-secreated but common ones = chronic unfitness, weakness, faitgue, loss of appetite, cold intolerance, sexual dysfunction
- Caused by tumours, acidental damage (radiation or surgery)
What is Panhypopituitarism
When ALL hormones secreted by the pituitary gland is disturbed
What is another name for growth hormone and where is it secreted from
Somatotropin or Somatropin
Released by pituitary
What do normal levels of growth hormone do?
Influences height, helps build muscles and bones
- boosts proliferation of cells and regeneration of tissues
- promotes healthy growth and weight gain in children and adolescents
- augments bone density and muscle mass
- ensures balance of body fluids (fats, water, blood)
- controls glucose synthesis, uptake and protein/lipid metabolism
- boosts energy levels/productivity/cognitive function/brain health
Describe the symptoms of GH deficiency in children/adolescents
Affects physical development - linear bone growth
Delays puberty- normal intelligence
Affects function of liver protein = short stature and immature facial features
Describe the symptoms and possible cause of GH deficiency in adults?
Symptoms…
- destruction of bone cells = fractures and osteoporosis
- affects metabolism
Possible cause…
- lack of GHRH or lack of GH secreating cells ie. non-functional tumours
What are the impacts on the oral cavity in children with GH deficiency
- md and mx growth effected
- tooth root and development of supporting structures retarded
- malocculsion, smaller arches
- delays in erupion and shedding
Describe the symptoms and possible cause of GH excess (acromegaly) in adults?
Acromegaly!
- Jaws, fingers, toes are bigger and bones become thicker
- forehead bosses and slants
- lower jaw protrusion
- flaring and spacing of anterior teeth
- enlarged soft tissues (tongue, liver, kidneys)
- Spiky exostosis- growths in alvelor bone.
- increased risk of diabetes
Possible causes…
- slow growing pituitary adenoma (tumour)
- headaches, poor vision, heart failure, weakness
Describe the symptoms and possible cause of GH excess in children (pituitary gigantism)
Pituitary gigantism
- abnormally large height and weight at young age
- rapid growth of all body tissues
- hyperglycaemia (overactive B cells) - type 2 diabetes
- death in early adulthood
Possible causes…
- acidophillic growth hormone-producing cells are excessively active or have acidophilic tumour
What are the impacts on the oral cavity in adults with GH excess (acromegaly)?
- Mandibular prognathism and thickening
- incerased thickness and height of alveolar process
- spacing and flaring of anterior teeth
- malocculsion
- enlarged tongue
Dentists well placed for early identification
Describe the symptoms of ADH deficiency in adults
Diabetes insipidus…
- excessive water loss
- drink alot and pee alot
- xerostomia
What do normal levels of ADH (vasopressin) do?
Regulate water balance
- act on kidneys to promote water reabsorption from forming urine (smaller amt/concentrated urine)
- cause vasoconstriction/raises BP
Synthesised in Hypothalamus: released by posterior pituitary in response to increased plasma osmolarity (high salt).
Describe the components of the ‘thyroid system’ ie. glands and hormones involved
Hypothalamus - TRH (thyrotopin releasing hormone)
Anterior pituitary - TSH (thyroid stimulating hormone)
Thyroid gland - Thyroid hormones T3 (Triiodothyronine) & T4 (thyroxine)
What do normal levels of T3 & T4 do
Increased metabolism and protein synthesis
- Effect growth and deveopment (including mental deveopment)
- Increased catecholamine effect
What is the stimuli for TRH release
- Cold
- Stress/emotional reactions
- Sleep
Grave’s Disease is known to cause hyperthyroidism:
Describe the symptoms and possible causes of hyperthyroidism in adults
Symptoms…
- increased skin temp and excess sweating
- tachycardia/irregular heart rate
- tiredness, muscle weakness, difficultly sleeping
- twitching/trembling
- anxiety
- exophthalmos (protruding eyes)
- increased sensitivity to catecholamines
Possible causes…
- High T4 (thyroxine)
- Graves disease (autoimmune disorder assoc. with thyroid-stimulating antibodies) (high TSH)
- toxic goitre (enlargment of thyroid)
- adenoma (tumour)
What is Thyrotoxicosis
Syndrome caused by high levels of thyroid hormone
- normally due to hyperthyroidism
What are the impacts on the oral cavity of hyperthyroidism
- more susceptible to peridontal disease & caries
- sensitive to adrenaline (L.A’s) -> hypertensive crisis?
- stress assoc. exaserbate cardiovascular issues
big concern = thyroid storm ie. thyrotoxic crisis (life threatening)!
What are the two possible causes of hypothyroidism
Aquired
- due to surgury, drugs ie. lithium, excess or lack or iodine
- Hashimotos thyroditis: autoimmune reaction destorys thyroid
Congenital
- causes cretinism (physical deformity and mental retardation)
Describe the symptoms of hypothyroidism in adults
Hypometabolism
- fatigue, weight gain despite loss of appetite
- cold intolerance
- myxedema (puffy appearance)
- pericardial or pleurral effusion (build up of fluid)