Lecture 4: Endocrine Flashcards
The endocrine system work with the nervous system to handle what 2 responsibilities
- Homeostasis
2. Feedback mechanisms
What is a key difference between the nervous system and the endocrine system
- Nervous system is fast acting and reacting
- Endocrine system slow but long lasting response
What are endocrine glands and their primary functions (3)
- units of secretion
- to create, release and distribute hormones
What are the 6 endocrine glands
- Pineal body or gland (a.k.a epiphysis)
- Pituitary (a.k.a. hypophysis)
- Thyroid
- Parathyroid
- Thymus
- Adrenal
What are the endocrine tissues and organs
- partly hormonopoietic
- they have the capacity to create hormones but that is not their primary function
Name the 10 endocrine organs
- Pancreas
- Ovaries
- Testicles
- Kidneys
- Stomach
- Adipose tissue
- Small intestine
- Skin
- Heart
- Placenta
What hormones does the pancreas produce
- insulin
- glucagon
What hormones do the ovaries produce
- estrogen
- progestrone
What hormones do the testicles produce
-testosterone
What hormones do the kidneys produce
-erythropoietin
What hormones does the stomach produce
- gastrin
- serotonin
What hormones does adipose tissue produce
-leptin
What hormones does the small intestine produce
- secretin
- cholecystokinin
- gastrin
What hormones does the skin produce
-cholecalciferol (inactive form of vitamin D)
What hormones does the heart produce
-atrial natriuretic peptide (ANP)
What hormones does the placenta produce
- estrogen
- progestrone
- hCG
What is a neuroendocrine organ
-translator or interface of the two systems
What is the 1 neuroendocrine organ
Hypothalamus
What are the 2 ways to classify hormones
- function
- structure
What are the 3 functional classifications of hormones
- tropic hormones (target other endocrine glands)
- sex hormones (target reproductive tissues)
- anabolic hormones (stimulate anabolism)
What are the 2 structural classifications of hormones
- steroid
- nonsteroid
What are the 4 types of nonsteroid structures of hormones
- protein
- peptide
- amino acid derivative
- glycoprotein
What is the lock and key mechanism
- the target cell has a receptor specific for the hormone that affects it
- each hormone attaches to a specific receptor
What is signal transduction principle
- the transmission of molecular signals from a cell’s exterior to it’s interior
- different hormone, different effects
What is the principle of synergism
-occurs when 2 or more hormones produce the same effects in a target cell and their results are amplified
what is the principle of permissiveness
-the situation in which a hormone cannot exert its full effects w/o the presence of another hormone
What is the principle of antagonism
- pairs of hormones that have the opposite effects
What two ways can hormones be soluble
water or by lipid
what are the 2 mechanism that hormones can be transported through
- receptor mediated transport
2. diffusion
What is receptor mediated transport
- Proteins on the outside of the cell membrane are receiptors to allow hormones to produce their effect on cell
- hormones cannot enter cell alone as water soluble molecules cannot penetrate the mebrane very well
- energy is required
- most hormones are transported this way
What is an example of receptor mediated transport
hormone derived from amino acids
What is the transport mechanism diffusion
- membrane primarily made up of fats
- makes it easy for lipids to pass through freely
- they have a direct action on genes (no additional signaling steps)
- based on chemistry: molecules that are alike dissolve each other (solubility)
What is an example of the diffusion hormone transport
-steroid hormones (synthesized from cholestrol)
What are the 3 ways to promote endocrine hormone release
- ion concentration (altered levels of critical hormones)
- action potential (caused by neural input)
- hormones (hormone release caused by another hormone that’s a-tropoic)
What is target cell regulation
-a target cell responds to a hormone bcs it bears receptors for the hormone.
-sensitivity is dependant on # of receptors
-hormone receptors must be broken down on receptor to end effect
up-regulation vs down-regulation
What are the 3 subgroups of eicosanoids
- prostaglandins
- thromboxanes
- Leukotrienes
What are 2 characteristics of eicosanoids
- rapidly metabolized, do not circulate far
- work on a cellular level
What are Prostaglandins
- 16 diff PGs total & 9 classes (A - I)
- many involved w/ cAMP cycle (secondary messenger cycle)
What are 3 examples of prostaglandins
- PGA (decrease BP -> increase in regional flow in heart and kidneys
- PGE (platelet aggregation & RBC shape, role in inflammation response)
- PGF (involved w/ uterine contractions, peristalsis)
What are Thromboxanes
-synthesized by platelets, involved w/ clotting
What are Leukotrienes
Involved w/ immune responses
What is the other name for neurohypophysis
posterior pituitary
Where are hormones that are produced in the hypothalamus stored
in posterior pituitary
What are the 2 nuclei of the hypothalamus that produce hormones
- Supraoptic nucleus (antidiuretic ADH or vasopressin)
2. paraventricular nucleus (oxytocin)
What is antidiuretic hormone (ADH) of the posterior pituitary
- AKA vasopressin
- maintains water balance via water retention in kidneys
- stimulates contraction of small arterioles
What is oxytocin (stored in posterior pituitary)
2 primary roles:
- stimulation of uterine muscles
- ejection of milk frm mammary glands
- important for bonding btw mother and child
What is the Adenohypophysis
Anterior pituitary
What are the 5 distinct types of secretory cells in the anterior pituitary
- Somatotrophs (growth hormone GH)
- Lactotrophs (prolactin PRL)
- Corticotrophs (adrenocorticotropic hormone ACTH)
- Thyrotrophs (thyroid stimulating hormone TSH)
- Gonadotrophs (follicle-stimulating hormone FSH, luteinizing LH)
What is the growth hormone / somatotroph (in anterior pituitary)
- promotes growth via insulin-like growth factor 1 (IFG-1), frm liver
- increases amino acid transport into cells
- stimulates protein anabolism
- stimulates metabolism of fat
What is prolactin (PRL) (in anterior pituitary)
-initiation of milk secretion
What is adrenocorticotropic hormone (in anterior pituitary)(ACTH)
-promotes development of adrenal glands and secretion of cortisol
What is Thyroid-stimulating hormone-TSH (in anterior pituitary)
- promotes growth of thyroid
- stimulates production of thyroid hormone
What is Follicle-stimulating hormone -FSH (in anterior pituitary)
- stimulates primary follicles to mature
- causes synthesis of estrogen
- development of seminiferous tubules & spermatogenesis in males
What is Luteinizing hormone - LH (in anterior pituitary)
- stimulates corpus luteum (yellow body)
- releases progesterone
- stimulates testes development in males & testosterone production
What are the hormones generated and released in the hypothalamus (7)
- Gn-rh: gonadotropin releasing hormone
- Growth hormone releasing hormone
- Growth hormone inhibiting hormone
- TRH: Thyroid releasing hormone
- PRH: Prolactin releasing hormone
- Pih: Prolactin inhibiting hormone
- CRH: Corticotropin releasing hormone
Where do the hormones go after released from anterior and posterior pituitary
the target organ
What happens when there is hyposecretion of GH
-child: pituitary dwarfism
What happens when there is hypersecretion of GH
gigantism: normal proportion
- acromegaly (adult): irreversible thickening of bone in hands, face, skin
What happens when there is hyposecretion of TSH
- child: cretinism / menatally retarded
- adult: myxedema-edema of face and extremities
what happens when there is hypersecretion of TSH
- graves’ disease (autoimmune exophtalmos)
- Hashimoto (autoimmune, goiter)
What happens when there is hyposecretion of ACTH
-addison disease(life threatening, weakness, anorexia, dehydration, nausea, circulatory shock)
What happens when there is hyposecretion of ADH
diabetes insipidus: excretion of large quantities of diluted urine
What happens when there is hypersecretion of ADH
- syndrome of inappropriate ADH secretion
- retention H2O
- headache
- weight gain
Where is the thyroid gland
- seated on the larynx
- bounded (superiorly) by thyroid cartilage and (inferiorly) by the trachea
What are the 3 hormones in the thyroid gland
- T3 (triiodothyronine)
- T4 (tetraiodothyronine) / Thyroxine - secreted by follicular cells, collectively known as thyroid hormone
- Calcitonin ( secreated by parafollicular)
What is the function of the thyroid hormones T4 and calcitonin
thyroid hormone: metabolism and growth
Calcitonin: -regulation of circulating calcium
-calcium deposits for bone
What are the functions of the thyroid gland
- controls metabolism (weight + or -)
- regulates damaged and dying cell replacement
- affects HR
- affects temp and temp regulation
- affects the strength of muscles
What are the effects of hypothyroidism (long list so just a few)
- hair loss
- apathy
- lethargy
- dry skin (coarse and scaly)
- muscle aches & weakness
- constipation
- intolerance to cold
- receding hairline
- facial & eyelid edema
- dull blank expression
- extreme fatigue
- thick tongue - slow speech
- anorexia
- brittle nails and hair
- menstrual disturbances
- late stage: (subnorm temp, bradycardia, weight gain, decr. LOC, thickened skin, cardiac complications)
What are some affects of hyperthyroidism (long list so just a few)
- intolerance to heat
- fine straight hair
- bulging eyes
- facial flushing
- enlarged thyroid
- tachycardia
- increased systolic BP
- breast enlargement
- weight loss
- muscle wasting
- localized edema
- finger clubbing
- tremors
- increased diarrhea
- menstrual changes (amenorrhea)
Where is the parathyroid gland
- -on the posterior aspect of the thyroid gland
- embedded within the thyroid gland
What 3 areas do the hormones released from parathyroid target
- skeleton
- kidney
- intestine
What is the function of the parathyroid
Principal cells secrete parathyroid hormone - PTH
-activated when Calcium is in low concentrations in the blood
What is the effect of hyperparathyroidism
leaching of bone Ca2+ = spontaneous fractures
hypercalcemia gives lethargy, constipation, possible coma
What is the effect of hypoparathyroidism
Hypocalcemia (rare), increased phophorus
=increased excitability of neurons and muscle cells, muscle spasms, convulsions
Where is the adrenal gland
- lies on the superior aspect of the kidneys
- broken down into 2 regions
What are the 2 regions of the adrenal glands
- adrenal cortex
2. adrenal medulla
What are the 3 zones of the addrenal cortex
- zona glomerulosa (mineralcorticoids ex.Aldosterone)
- zona fasciculate (glucocorticoids ex.Cortisol)
- zona reticularis (gonadocorticoids ex.testosterone & estrogens)
Characteristics of the adrenal medulla
- under the control of the sympathetic nervous system
- secretes catecholamines (adrenaline & noradrenaline)
What is glucocorticoid activity most commonly associated with
the release of stress hormone Cortisol
What is the principal metabolic effect of glucocorticoid activity
gluconeogenesis
- formation of glucose frm noncarbohydrate molecules
(ex. amino acids, glycerol) - elevated cortisol suppresses immune system
What is Cushing disease
-disease of excess cortisol
= persistent hyperglycemia, HTN, edema, buffalo hump (fat in neck), fragile skin, muscle weakness
What are the 3 main catecholamines
- epinephrine (adrenaline)
- norepinephrine (noradrenaline)
- dopamine
what happens when there is hypersecretion of catecholamines
- increased metabolism
- increased cardiac frequency
- hyperglycemia
- palpations
- nervousness
- HTN
- diaphoresis
what happens when there is hyposecretion of catecholamines
-inability to handle stress
What is the specialized cell of the Pineal gland
Pinealocytes
what are Pinealocytes responsible for
the secretion of melatonin
What is melatonin
- implicated w/ biological clock
- sleep & wake cycle
- hallucinations (DMT)
- potent antioxidant
- cancer therapeutic
- body has many receptors for it
What suppresses melatonin
bright (blue) light
- so highest activity happens in darkness
What are the special secretory cells of the thymus
thymocytes
Thymocytes are responsible for the production and release of what 5 diff hormones
- prothymosin
- Thymosin
- Thymopoietin
- Thymulin
- Thymic humoral factor
What is the function of the thymus hormones (3)
- favor the proliferation & maturation of T-lymphocytes (innate immunity)
- maintain & balance other lymph tissues
- involved in differentiation of B cells to plasma cells for antibody production (memory & diversity)
Where is the pancreas located
-long, flat gland that lies horizontally behind stomach
what 2 systems does pancre
endocrine and digestive
The endocrine portion of the pancrease is made up of what?
islets langerhans
What are the 5 types of cells of islets langerhans
- Alpha (secrete glucagon)
- Beta (secrete insulin)
- Delta (secrete somatostatin; involved in regulating the pancreas)
- Epsilon (secrete ghrelin, induce appetite \; slows metabolism)
- PP cells (secrete pancreatic polypeptide, role in digestive sys.)
What is hypoglycemia
low BG (blood glucose/ blood sugar)
what are signs/ symptoms of hypoglycemia
- sweating
- mood changes
- blurred vision
- trembling
- dizziness
- hunger
- H/A
- extreme tiredness & weakness
What are signs / symptoms of hyperglycemia
- dry mouth
- freq. urge to urinate
- freq. bed wetting
- xtreme thirst
- drowsiness
- stomach pain
What is Diabetes Mellitus
- absence, insufficient, inefficient quantity of insulin
- Glucose not absorbed by cells leading to hyperglycemia
- cells enter starvation mode
- leading to breakdown of glycogen and lipids, production of glucose
- can lead to Glycosuria
What is glycosuria
sweet smelling urine
What is type 1 diabetes
no insulin
what is type 2 diabetes
less insulin and insulin resistance
what is gestational diabetes
high glucose levels in mom - brings extra glucose to baby - causes baby to put on extra weight
