intro Flashcards
(41 cards)
The glands
-hypothalamus- within brain -> releasing hormones -> effect pituitary gland
-pituitary- you can see it -> trophic hormones act on distal target organs
-thyroid- TRH (hypothalamus) -> TSH (pituitary)
-parathyroid- 4 small glands
-pancreas- islets of langerhans
-adrenals
-gonads
posterior pituitary gland
-has STORED* hormones
Directly innervated by hypothalamic neurons via the pituitary stalk:
Posterior pituitary secretion of
-Vasopressin (antidiuretic hormone; ADH)
-Oxytocin
-Both are very sensitive to NEURONAL damage by lesions that affect the pituitary stalk or hypothalamus
primary organ/problem** vs secondary vs tertiary
PRIMARY:
-the distal organ that actually has the disease
-primary problem is in the target organ/peripheral endocrine gland
-ex. decrease T4 production -> dysfunction in thyroid gland itself -> primary hypothyroidism
2ndary problem
- pituitary problem
-ex. hypo functioning of the pituitary gland -> no stimulation to thyroid gland to produce T4 -> secondary hypothyroidism
Tertiary problem
- hypothalamus problem (rare)
endocrinology
Endocrinology: “to set in motion”
-endocrine = ductless
-works elicit cellular responses and regulate physiologic processes through feedback mechanisms
different mechanisms of cell signaling (she brushed over this)
-intracrine- within cell
-autocrine- from within cell to outside -> back in
-paracrine- local
-endocrine- general circulation
-neuroendocrine
Posterior pituitary hormones
1) oxytocin
2) Vasoactive peptide (AVP)/ antidiuretic hormone (ADH)
-AVP/ADH deficiency = diabetes insipidus (DI) -> lots of dilute urine and extreme thirst
-excessive or inappropriate AVP production = hyponatremia if water intake is not reduced in parallel with urine output
Hypothalamus Hormones
TRH, CRH, GnRH, GHRH, Somatostatin, Dopamine
(The Coolest Girls Get Sick D*ck)
What are the anterior pituitary hormones?
TSH, FSH, LH ,ACTH , MSH , Growth Hormone and Prolactin
What are the thyroid hormones? T3 and T4 repress…..
T3 and T4
T3 and T4 repress TSH
-NEGATIVE feedback
- -increase in hormone from target organ (ex. T4) -> sends signal to pituitary and hypothalamus to decrease stimulating hormones (decrease TSH and TRH)
basic genetics of hormones (she brushed on this…dont really study)
The synthesis of peptide hormones and their receptors occurs through a classic pathway of gene expression ->
Transcription → mRNA → protein → posttranslational protein processing → intracellular sorting, membrane integration, or secretion ->
Have regulatory DNA elements ->
-Control by other hormones also necessitates the presence of specific hormone response elements
-Insulin synthesis requires ongoing gene transcription but at the translational level is controlled by the glucose & amino acid levels
physiology: what type of binding, receptor types, and what is the Hypothalamic- pituitary relationship
Selective binding
- regulation of gene function and enzyme action
Receptors
- membrane
- nuclear
Hypothalamic- pituitary relationship -> middle man
-varying degrees of control
-negative feedback control mechanism
hormones to target organs image
-cortisol- most important hormone*- you can not live without it -> controls BP and glucose
-every cell needs T4 for metabolism
-FSH & LH - affect testes and ovaries
-prolactin- produces breast milk itself
-ADH -> kidneys
-oxytocin -> breasts and uterus
hormone flow chart
-somatostatin - inhibits GH and TSH
-IGF*- part of GH that affects the tissues and long bones
-GH- affects glucose
-TSH can affect prolactin
hyperthyroidism
-increase T4
-tachycardia, sweating, diarrhea, anxiety, tremors
-increased metabolism
-constipation, depressed, gained weight, myxedema, slower movements
-problem is in the thyroid?, pituitary?, hypothalamus?
What factors stimulate growth vs what leads to epiphyseal closure
stimulate growth:
-GH
- IGF-I
- thyroid
epiphyseal closure:
- sex steroids
Factors involved in short stature
-GH deficiency,
-hypothyroidism
- Cushing’s syndrome,
-precocious puberty,
-malnutrition or chronic illness
- genetic abnormalities
reproduction
Sex determination, puberty, pregnancy, menopause
What factors involved in maintaining homeostasis?
-TSH
- PTH
- Cortisol**
- Vasopressin
- Insulin
hyperfunction
OVERSECRETION of hormones
-produced by a certain set of cells
Causes:
-tumors (benign (MOST) or malignant)* MC
-hyperplasia of endocrine gland
-ectopic secretion of hormones by other tumors
-ex. lung cancer -> increase ADH (malignant)
hypofunction
Under stimulation from pituitary or abnormal tissue response
tx: replacement of hormone or hormone stimulating drugs
hormone secretion, transport, and degradation
Stored in secretory granules
-releasing factors or neural signal -> ion channels -> secretion of hormone
Transport and degradation
- affect the rapidity with which its signal decays
-frequency of dosing and the time required to reach steady state are closely linked to RATE of hormone decay
The circulating level of a hormone is determined by:
- rate of secretion and its circulating half life
-half life important for achieving physiologic hormone replacement
hypothalamo- pituitary axis
adenohypophysis = anterior pituitary
-portal vascular system: blood vessels connect hypothalamus and anterior pituitary
Neurohypophysis- neuronal control; posterior pituitary
Cyclical release of hormones:
-pulsatile release of hormones
-circadian rhythms- it matters when you do the blood draw (morning vs night) for ACTH, GH, prolactin
-month long rhythms with superimposed circadian rhythms: LH, FSH
If pituitary stalk is severed what increases and what decreases?
Pituitary stalk is severed:
- prolactin release INCREASES because it is regulated by INHIBITORY STIMULI
- release of all other anterior pituitary hormones DECREASE because it is regulated by POSITIVE FEEDBACK