Hormones
Chemicals made by cells that affect growth or function of other targeted tissues/organs
involved in metabolism, growth, sexual dev, stress, etc
Endocrine system
Collective group of cells capable of secreting hormones
Can only cells of endocrine system release hormones?
No (immune system cells release cytokines, neurons release NT)
Characteristics of hormones: Control is regulated via __?
Hypothalamic-pituitary axis
Characteristics of hormones: Feedback
modification or control of a process or system by its results or effects
hypothalamus receives input in form of NT, chem mediators, etc
can be neg or pos
Characteristics of hormones: when a hormone binds to a receptor, what are the two outcomes that may happen?
Act on target organ to achieve effect
Act on gland to produce another hormone
What are the releasing hormones produced by the hypothalamus?
Growth hormone (GH)
Thyrotropin
Corticotropin
Gonadotropin
(All have -releasing hormone to the end of them)
What are the inhibiting hormones produced by the hypothalamus?
Dopamine (inhbits prolactin)
Somatosin (inhibits GH and TSH)
Anterior pituitary gland function
Receives signal from hypothalamus via circulation
under neg feedback regulation
Posterior Pituitary gland function
Direct neural connection (axons)
not under neg feedback regulation
What hormones does the APG release?
luteinizing hormone
Adrenocorticotropin
Prolactin
GH
Thyroid stimulating (TSH)
Follicle stimulating (FSH)
Corticotropin releasing hormone (CRH)
Released by hypothalamus and acts on anterior pituitary to release adrenocorticotropic hormone
Adrenocorticotropic hormone (ACTH)
Released by anterior pituitary gland (from CRH binding)
acts on adrenal cortex
stimulates release of hormones (Aldosterone and cortisol)
Gonadotropin releasing hormone (GnRH)
Released by hypothalamus and acts on anterior pituitary gland to release LH (leutinizing hormone) and FSH (follicle stimulating hormone)
follicle stimulating hormone (FSH)
Released from anterior pituitary gland (from GnRH binding)
targets reproductive organs and stimulates sexual reproduction (ovulation in women; sperm production in men)
Growth hormone releasing hormone (GHRH)
released by hypothalamus and acts on pituitary gland to release growth hormone
Growth hormone (GH)
Released by anterior pituitary (when GHRH binds)
Targets bones, muscles, tissues
stimulates growth
Thyrotropin releasing hormone (TRH)
released by hypothalamus and acts on anterior pituitary gland to release thyroid stimulating hormone
Thyroid stimulating hormone (TSH)
Released by the anterior pituitary (When TRH binds)
Acts on thyroid gland to produce secretion of thyroid hormones (T3 and T4)
Positive feedback loop
presence of hormone stimulates increased production of hormone until cycle interrupted
less common (Example: oxytocin released during labor; stretching happens)
Negative feedback loop: what are the two mechanisms
Low levels of hormones stimulates release of more hormones
High levels of hormones inhibit release of hormones
dirunal patterns of secretion
Daily
What must hormones bind to in order to elicit a response?
Receptor
Cell to cell communication: Paracrine
Hormone cell communicating to nearby cell
Cell to cell communication: Autocrine
Hormone cell communicating to self
Cell to cell communication: Endocrine
Hormone cell communicating with capillary (helps with far distance)
Cell to cell communication: Synaptic
Hormone cell (neuron) communicating via neuron to neuron (axon/terminal to dendrites)
Cell to cell communication: Neuroendocrine
Hormone cell (neuron) communicating with capillary
What did Dr. Hans Selye do?
Discovered new sex hormone
Injected ovarian extract into rats
What is stress?
Threat to homeostasis
Can be real or perceived
can be good or bad
Stage I of stress
Stimuli from senses sent to brain
Stage II of stress
Brain deciphers stimulus as threat or non threat
Stage III of stress
Body stays activated until threat gone
Stage IV of stress
Body returns to homeostasis
threat gone
Stress hormones: Catecholamines
Norepinephrine (released from presynaptic neurons)
Epinephrine (secreted by adrenal medulla)
Stress hormones: Glucocorticoids (steroid hormone)
Cortisol (secreted by adrenal cortex)
Immune system effects in response to stress
Decreased resistance to infection
alteration of immune response
Selye's General Adaptation Syndrome: alarm stage
Stressor triggers hypothalamic-pituitary-adrenal axis (HPA)
Selye's General Adaptation Syndrome: Resistance (adaption) stage
Begins with action of adrenal hormones (cortisol, (nor)epinephrine)
Selye's General Adaptation Syndrome: Exhaustion stage
Occurs only if stress continues and adaption is not successful
Altered hormone function
Impairment of endocrine gland
Lack of/excessive hormone synthesis
Impaired receptor binding
Impaired feedback mechanisms
Impaired cell response to hormones
Hypopituitarism
not enough hormones via pituitary gland
Results in fatigue, dry skin, growth impairment, anorexia,etc
Diagnosing altered hormone function
History and physical examination
Lab tests (serum and hormone levels)
Imaging
Genetic test
Altered hormone function treatment
Removal of tumor releasing hormone
medication that replaces hormone deficiency
Syndrome of inappropriate antidiuretic hormone (SIADH) pathophysiology
Excessive production and release of ADH (usually caused by tumor secretion)
water accumulates in cells
Sodium diluted in extracellulat space
What is the result of Syndrome of inappropriate antidiuretic hormone (SIADH)?
Hypotonic hyponatremia
Syndrome of inappropriate antidiuretic hormone (SIADH) Clinical manifestations
Decreased urine output
Anorexia
nausea
psychosis
coma
seizure
(depends on serum sodium levels)
Syndrome of inappropriate antidiuretic hormone (SIADH) diagnostic criteria
hyponatremia
Hypotonicity
Decreased urine volume
concentrated urine (high sodium)
Syndrome of inappropriate antidiuretic hormone (SIADH) treatment
Remove cause
water restriction
Isotonic or hypertonic IV fluid
pharmacologic treatment
diabetes insipidus (DI) pathophysiology
Insufficient ADH
inability to retain water
diabetes insipidus (DI) clinical manifestations
Polyuria
Excessive thirst
Dehydration
Shock
diabetes insipidus (DI) diagnostic criteria
ADH levels
Serum solute concentration
Urine specific gravity
diabetes insipidus (DI) treatment
Treat cause
hydration
Desmopressin (Anti diuretic)
another name for hyperthyroidism?
Grave's disease
Hyperthyroidism (Graves disease) pathophysiology
Excessive thyroid hormone due to excess stimulation of thyroid gland, disease of thyroid gland, or excess production of TSH
What type of hypersensitivity is Grave's Disease
Type II
IgG binds to TSH receptors
Hyperthyroidism (Graves disease) clinical manifestations
Goiter
Weight loss (fast metabolism(
Tremors
Sweating
Weakness
Exopthalmos (Excessive inflammation)
Hyperthyroidism (Graves disease) diagnostic criteria
Sertum TSH (Low)
Serum T3/T4 (High)
Hyperthyroidism (Graves disease) treatment
meds that block T3/T4 production
Surgical removal of gland (requires thyroid HRT after)
Hypothyroidism pathophysiology
Deficiency of thyroid hormone (T3/T4)
happens due to lack of thyroid development, deficient synthesis of TH, impaired secretion of TSH or TRH
Hypothyroidism clinical manifestations
Fatigue
cold intolerance
constipation
Goiter
weight gain
Hypothyroidism diagnostic criteria
TSH levels (high)
total T3 and T4 uptake
Hypothyroidism treatment
lifelong thyroid HRT
Cushing syndrome pathophysiology
Excess glucocorticoids secreted from adrenal cortex
Cushing syndrome clinical manifestations
Metabolic alteration
obesity of trunk, face, and upper back
Glucose intolerance
Suppression of immunity/inflammation
impaired stress response
Cushing syndrome diagnostic criteria
Cortisol levels in 24 hoururine
imaging studies (detect tumor that may be secreting)
Cushing syndrome treatment
Remove cause of excess cause of cortisol secretion
Addisions disease pathophysiology
Autoimmune destruction of adrenal cortex
glucocorticoid deficiency
ACTH levels increase to make up for deficiency
Addisions disease clinical manifestations (glucocorticoid deficiency)
Darker pigmentation of skin (from high ACTH)
Hypoglycemia
Weakness
weight loss
personality changes
Addisions disease clinical manifestations (mineralocorticoid deficiency)
dehydration
hyponatremia
hyperkalemia
hypotension
Shock
Addisions disease diagnostic criteria
Hyponatremia
hyperkalemia
Corticosteriod levels low after ACTH administered
Addisions disease treatment
Fluid replacement
Oral glucocorticoid and mineralocorticoid replacment
A patient with a "buffalo hump" and a "moon face" enters the primary care clinic. Which diagnosis is most likely for this patient?
Cushings syndrome