Ch. 32 Flashcards
What has to be present for a cell to respond to a hormone?
the receptors for the hormone.
What is down/up regulation?
cell makes fewer/more hormone receptors
Do different cells respond differently to the same hormone?
YES
progesterone enlarges breast tissue, while it does something different in the uterus
What is endocrine function?
hormone has to travel in circulation
What is paracrine function?
hormones act on nearby cells
What is autcrine function?
hormone effects cell that made it
Where is T3 and T4 destroyed and passed out?
The liver and in bile
What is a primary hormone disorder?
an abnormality in the gland where the hormone is produced
What is a secondary hormone disorder?
This is where there is an abnormality in the stimulation from the pituitary.
What is a tertiary hormone disorder?
there is an abnormality in the stimulation from the hypothalamus
What happens with hormone regulation after the outside input has been processed by the hypothalamus?
The hypothalamus will decide to secrete more or less of a releasing hormone that will act on the pituitary gland
The pituitary gland will then release stimulating (trophic) hormones that will act on a peripheral gland
The peripheral gland will then release its hormone which will act on its target cells
What are the pituitary hormones that we need to know?
GH (growth hormone)
TSH (thyroid stimulating hormone)
What
What is the most common cause of hyperpituitary?
anterior pituitary adenoma
What are the S/S of hyperprolactinemia?
WOMEN:
amenorrhea - loss of period
galactorrhea - milk production without pregnancy
infertility
MEN:
impotence
loss of libido
galactorrhea
SOMETIMES BECAUSE OF CLOSE PROXIMITY TO OPTIC NERVE THERE WILL BE VISUAL ISSUES: LIKE LOSS OF PERIPHERAL FIELD
With hypopituitary, is it all the cells being affected, or a specific subset?
it can be either or
How much of the pituitary must be destroyed in order for hypopituitary to manifest?
70-90%
What are the causes of hypoptuitary?
congenital hypopituitary, space occupying lesions, or radiation therapy
Does hypopituitary progress rapidly?
No, its usually slow in prgression
What is the typical order you will loose hormones with hypopituitary?
1: GH, LH, FSH
2: TSH
3: ACTH
4: prolactin
What is another name for growth hormone?
somatotropin
What stimulates the release of GH??
hypoglycemia
fasting
starvation
stress
What inhibits GH secretions?
hyperglycemia, free fatty acid release, obesity, cortisol
`How do the growth promoting actions of GH work?
It tells the liver to secrete IGF-1 (insulin like growth factor)
this causes an increase in protein synthesis
This causes the bone and cartliage linear growth to increase, an increase in the size and function of body organs, and an increase in lean muscle mass
What are the anti-insulin actions of GH?
It increases lipolysis of adipose tissue, which increases our use a free fatty acids, as well as a decrease in adipose tissue
It also decreases the use of carbohydrates (glucose), which INCREASES BLOOD GLUCOSE
Can GH make cells resistant to insulin?
yes yes yes
What can be the causes of GH deficiency?
Idiopathic GH deficiency: lack of hypothalamic GHRH
pituitary tumors or agenesis of the pituitary: cant produce GH
Laron-type dwarfism: heredetary defect in IGF production
How do we name a GH excess that happens in different stages of life?
childhood: gigantism
adulthood: acromegaly (mainly effect cartilagenous tissue because growth plates have closed by this time) also can see heat intolerance, oily skin, muscle weakness, menstrual irregularity
What are some other manifestations of GH excess?
HTN
sleep apnea
paresthesias
headaches
ALL OF THIS IS FROM OVERGROWTH THAT TRAPS OR OBSTRUCTS OTHER TISSUES
What is a common cause of GH excess?
benign adenoma
What hormones does the thyroid release?
T3 and T4
CARRIED BY BINDING PROTEINS
What do we measure to test for thyroid function
T3
free T4
TSH
anti-TPO antibodies (autu-immune (like hashimotots)) destroys receptor sites on thyroid for TSH
radioiodine uptake (radiographic test)
What does T3 stimulate?
metabolism and protein synthesis in nearly all tissues of the body (including CNS)
Is T4 active?
No, not until it is converted into T3, happens in tissues
What controls the negative feedback look of thyroid hormones?
levels of T4 and T3
COMMUNICATE TO HYPOTHALAMUS
What tissues aren’t effected by the thyroid?
testes, spleen, retinas, lungs
What effect does the thyroid have on all cells?
increases metabolic rate, and muscle protein used for food
How does the thyroid affect our cholesterol?
hypo: high cholesterol
hyper: low cholersterol
What does hyperthyroidism do to our muscles and vitamin supply?
muscle fatigue
vitamin deficiency
What do altered levels of thyroid hormone do to the heart?
Hyper: increased HR, contractility, CO (particularly dangerous increase in metabolism if some has atherosclerosis, danger of heart attack)
hypo: decreased HR, contractility, CO (very bad if someone has heart failure)
What do altered levels of thyroid hormone do to the GI tract?
hyper: diarrhea (increased motility, and production of secretions)
Hypo: constipation (decreased motility and GI secretions)
What do altered levels of thyroid hormone do to neuromuscular?
hyper: fine muscle tremor, nervous, anxiety
hypo: sluggish, mentally slow
How do we treat hypothyroidism regardless of the cause?
hormone replacement, (sometimes treatment for hyperthyroidism causes hypothyroidism and need for supplementation)
Can thyroid hormone cross the placenta? why is this important with congenital hypothyoidism?
YES
if the mom is providing the fetal thyroid hormone and the baby has a deficient thyroid, we wont know until the baby is born and shows symptoms)
What are some symptoms of a baby with hypothyroidism?
jaundice
hoarse cry
sluggish
umbilical hernias
feeding issues
What is the most preventable cause of mental retardation?
congenital hypothyroidism
What is the most common type of hypothyroidism?
acquired (more specifically hashimotos thyroiditis)
What are the types of acquired hypothyroidism?
hashimotos thyoiditis
thyroidectomy
What is another name for hyperthyroidism?
thyrotoxicosis
What is required for the synthesis of T3 and T4?
IODINE (if we dont have iodine we will have a decreased metabolism)
Is there a negative feedback to the hypothalamus for TSH?
NO NO NO
What happens if the thyroid cant make T3 or T4 and the hypothalamus continues to stimulate more and more production of T3 and T4 because of the low levels in the body?
The hypothalamus will continue to release TRH, which will tell the pituitary to make TSH, which will tell the thyroid to get to work.
This issue is that if the thyroid cant work to make these hormones (might not have the iodine building block to make it) then it will continue to get stimulated and will eventually hypertrophy causing a GOITER
What do we eat that has been supplemented with iodine?
salt
What are your T4 and TSH levels with hypothyroidism?
T4 low
TSH high
Is hypothyroidism a primary, secondary, or tertiary disorder most commonly?
PRIMARY
What can cause hypothyroidism?
thyroidectomy
radiation ablation
iodine deficiency or severe ingestion of iodine
hashimoto
Go more in depth about hashimoto thyoiditis.
This is an autoimmune disorder
The body has anti-TPO antibody that attacks the receptors on the thyroid for TSH, which means they dont make more T4
TSH is high and T4 is low
sometimes will present with a goiter, but not always
treated with supplements
What is myxedema?
a severe form of hypothyroidism where a levels get so low that we can go into a coma, become hypothermis (low metabolism), and cardiovascular collapse.
What are the symptoms of hypothyroid?
cold intolerance,lethargy, impaired memory, peripheral edema and puffy face, deep coarse voice, bradycardia, constipation, gastric atrophy (can lead to B12 deficiency), gain weight, swelling, muscle weakness, pallor, coarse brittle hair, large tongue, loss of lateral eyebrows
What is one of the most common causes of hyperthyroidism?
Graves disease
describe graves disease and its defining manifestations.
an autoimmune disorder that causes abnormal stimulation of thyroid gland by it TSH receptor antibodies, happens mainly in women from 20 to 40
diffuse goiter
exopthalmus
What are some other causes of hyperthyroidism?
multinodular goiter
adenoma
thyroiditis
iodine agent
Describe a thyroid crisis (storm).
this is a severe thyrotoxic state with very high mortality rate if not diagnosed early and treated immediately
mortality rates are mainly associated with the cardiac complications it causes
What is the function on ACTH? what secretes it?
It tells the adrenal cortex to produce hormones (cortisol, androgens, aldosterone)
the pituitary secretes it
What type of hormones are produced by the adrenal cortex?
steroid hormones (30 different ones)
What are these hormones synthesized from?
acetate and CHOLESTEROL
`What metabolizes the hormones made by the adrenal cortex?
The liver (funny because the liver makes the cholesterol that makes the hormone and also breaks it down)
What is the major glucocorticoid hormone?
cortisol
What do androgens do?
chief sex hormone
effects pubic and axillary hair growth and fetal placental growth
What is aldosterone?
major mineral corticoid steroid hormone
What does aldosterone regulate?
sodium, potassium and water
What regulates production of aldosterone as well?
renin and angiotensin levels
water, sodium, and potassium levels
What regulates the production of cortisol?
negative feedback loop with hyperthalamus, pituitary, and adrenal cortex system
What does cortisol do? (overview)
controls metabolic function of body and inflammatory response
What do we have if we have too much cortisol?
cushings syndrome
What effects does cortisol have on the body?
immune/inflammatory suppression
plasma proteins increased
CATABOLISM INCREASE:
muscle breakdown
sns response increase
blood glucose increase
free fatty acids increase
How does cortisol specifically affect the immune/inflammatory response?
inhibition of prostaglandin synthesis
decreased capillary permeability
depression of phagocytosis
reduction of fever
inhibition of fibroblasts (exudate and healing)
decreased antibody formation
`What are some things that can cause adrenal cortical disorders?
congenital adrenal hyperplasia
adrenal cortical insufficiency
excessive adrenal secretion
Describe congenital adrenal hyperplasia.
autosomal recessive trait
lacking enzymes needed to synthesize corticol, therefore an increase level of ACTH overstimulates adrenal androgens and causes hyperplasia
Describe adrenal cortical insufficiency, and the two types.
This is where the body cant make any of the 3 hormones
primary: addisons disease
secondary adrenal cortical isufficiency: issue with the pituitary gland OR withdrawal of glucocorticoids (mimics addisons disease)
What is an acute adrenal crisisand its symptoms?
This is a life threatening condition
causes nausea and vomiting, muscle weakness, hypotension, dehydration, and vascular
Other than cushings syndrome, what is another excess adrenal secretion condition?
hyperaldosteronism (a lot of time this is paired with cushings)
Why is it important to slowly wean people off of glucocorticoids?
This is important so we dont have a secondary adrenal cortical insufficieny that mimics addisons
What is another common time that people get a secondary adrenal cortical insufficiency?
when people are under a lot of stress.
Describe addisons disease.
this is a primary adrenal cortical insufficiency
RARE autoimmune
affects all layers of the adrenal cortex
associated with TB infection
What disorder mimics addisons disease?
secondary adrenal cortical insuficiency
What are some other causes a adrenal insufficiency?
metastatic carcinoma
fungal (histoplasmosis)
cytomegalovirus
amyloid disease
hemochromotosis
What are some manifestations of addisons?
hyperpigmentation of skin (bronze tone)
hypoglycemia
mucle weakness
loss of weight
vomiting diarrhea
cardiac insufficiency hypotension
adrenal atrophy destruction
urinary losses (sodium, water)
retention of potassium
What is hypercorticolism of any cause called?
cushings syndrome
What are the three important causes cushings syndrome?
tumor of pituitary gland (causes excessive ACTH production)
tumor of the adrenal gland
non-pituitary ACTH secreting tumnor
What is an iatrogenic cause of cushings sydrome?
long term cortisone therapy (stopping or weaning treatment cures it in this case)
What are some manifestations of cushings syndrome?`
buffalo hump and moon face (altered fat metabolism)
altered glucose metabolism (overt diabetes common)
skinny arms and legs, weakness, poor wound healing (protein breakdown and muscle wasting)
pupura
osteoporosis
bruising
amenorrhea
With cushings syndrome, will we also see an increase in mineralcorticoids and androgen levels?
YES YES YES
What is an incidental adrenal mass?
a tumor on the adrenal
most are benign
At what size should an incidental adrenal mass be removed?
4cm
