Bio Endocrine Flashcards
As peptide hormones are no polar they can’t pass the plasma membrane, what they do?
Binds to a receptor.
Hormone (1st messenger) binds to a receptor on the outside of the membrane which can activate multiple enzymes that trigger the production of the second messenger inside the cell( cAMP, IP3, Ca)
Most peptide and amino acid derivative hormone have names that end in?
In or ine
Fast onset bug short acting
Most steroid hormones have names end in?
Ol or oid
Slow but longer lasting change
How hormones act?
Peptide have surface receptors and act via second messenger systems
Steroid hormones bind to intracellular receptors and function by binding to DNA to alter gene transcription
What hormones are catecholamines?
Epinephrine and norepinephrine
Bind to G protein coupled receptors
Each step of the signaling cascade can induce what?
Amplification of the signal
What is negative feedback?
When a hormone or product later in pathway inhibits hormones or enzymes earlier in the pathway.
It maintains the homeostasis and conserves energy
What is hypophyseal portal system?
Blood vessel system that directly connects the hypothalamus with the anterior pituitary
What does dopamine do to prolactin?
Decreases it
High and low growth hormone cause in kids?
High - gigantism
Low- dwarfism
In adults high GH - acromegaly
ADH functions
Increased blood volume and higher blood pressure and decrease osmolarity
Does posterior pituitary synthesize its hormones?
No! They are synthesized in hypothalamus and released from posterior pituitary.
When T3 and T4 produced?
By the iodination of the tyrosine amino acid in the follicular cells of the thyroid. Number 3 and 4 refer to the number of iodine atoms attached to the tyrosine.
High T3 and T4 leads to decreased TSH and TRH - negative feedback
Deficiency of iodine in kids may result in?
Intellectual disability and developmental delay (cretinism)
Function of calcium
Decreased by calcitonin
Bone structure and strength
Release of neurotransmitters from neurons
Regulation of muscle contractions
Clotting of blood ( calcium is a cofactor)
Cell movement and exocytosis of cellular materials
High levels of Ca stimulated release of calcitonin
Antagonistic hormones
Glucagon and insulin
Parathyroid hormone and calcitonin
How does renin angiotensin aldosterone system works?
When BP is decreased, it is activated to increase blood volume, cardiac output and BP.
Negative feedback
Functions of pancreas
Endocrine: islets of Langerhans cells secrete hormones into blood vessels : alpha, beta, delta
Exocrine: acinar cells secrete digestive enzymes into pancreatic duct, tears and bile
What does diebetes people have very often?
Polyuria ( increased frequency of urination)
Polydipsia ( increased thirst)
Gonads function
Testes secrete testosterone in response to simulation of gonadotropins (LH, FSH)
Ovaries secrete estrogen and progesterone in the response to gonadotropins
Hormones table
Function of delta cells of pancreas
Somatostatin
Inhibits insulin and glucagon
Function of FSH
In males: Spermatogenesis
In females: growth of ovarian follicles
Function of LH
Males: testosterone
Women: induced ovulation
Function of calcitonin
Thyroid gland, decrease ca
Increase of ca in bone, decrease of ca in blood, decrease ca absorption in gut, increase ca excretion from kidneys
Parathyroid hormone function
Increase of Ca, bone breakdown
Decrrase ca in bone, increase in blood, increase absorption in gut, decrease extraction from kidneys
Vasopressin function
Posterior pituitary
Decrease water output in urine
Vasoconstriction
Aldosterone function
Adrenal cortex, mineralocorticoids
Decrease K in blood. Increase Na and water in blood due to osmosis , increase BP
Role of catecholamines in stress response
Melatonin function
Released by pineal grand in response to low light levels detected by the retina
Promotes sleep
Stress response
Adrenal glands hormone are similar that they
Secrete hormones that alter blood pressure
What calcitonin stimulates?
Vitamin D activation
Increased level of insulin causes
Blood glucose to decrease: decrease of glucagon release, decrease of plasma AA, decrease of gluconeogenesis, increase of glycogen stores, increase of triaglyceride synthesis and protein synthesis
Insulin sensitive and insulin resistant
Sensitive- only a minimal amount of insulin is needed to reduce glucose
Resistant- more insulin is needed to reduce the same amount of glucose
Appetite hormones are
Leptin when appetite suppressed during satiety made of adipose cells
gherlin when appetite is stimulated during hunger made from gastric cells by acting on cells in the hypothalamus
Cholecystokinin- gut derived hormone that promotes satiety
Posterior pituitary functions
Oxytocin and ADH
Storage site for neurohormones ( hormones released from neurons) that are released by exocytosis from the axons into the blood vessels that carry blood away from the posterior pituitary
Parathyroid hormone function
Raise calcium
Maintain normal osteoclasts activity in bone by increasing osteoclast activity and decreased bone mineralization in high PTH.
High release of PTH can be cause due to decreased synthesis of vitamin d which leads to decreased intestinal ca absorption
What is endocrine signaling?
Hormones are secreted into the bloodstream by specialized cells and transported throughout the body via the circulatory system. Once the hormone reaches its target tissue, it alters cellular function.
Long durable, cell to cell communication
G protein coupled receptor function
When the alpha subunit of a G protein is bound to GDP, the protein is inactive.
Upon ligand binding, GTP binds in place of GDP causing activation of phospholipase C. In case of IP3
