BIO 270 Exam 4 (final) - Hynd
processing of peptide hormones - ✔️✔️1. preprohormones are synthesized from rER
and migrate to Golgi in membrane bound vesicles
2. while in ER and golgi, preprohormones are processed into prohormones followed by
active hormones
3. golgi packages and labels hormones into secretory vesicles that are stored in
cytoplasm until appropriate signal
4. upon signal, vesicle membrane fuses with plasma membrane and peptide hormone is
exocytosed
major processes the endocrine system can regulate include... - ✔️✔️- reproduction,
growth and development
- elecrolyte/water/nutrient balance of blood
- cellular metabolism/energy balance
- immune defenses
hormone - ✔️✔️chemical released into blood to regulate distant target cells
hormones exert effect on _____ cells some distance away from the site of release -
✔️✔️target
endocrinology - ✔️✔️study of homeostatic activities accomplished by hormones
major glands of the central endocrine system - ✔️✔️hypothalamus and pituitary
major glands of the peripheral endocrine system - ✔️✔️thyroid, adrenal, parathyroid,
gonads
phospholipids - ✔️✔️double layered barrier that allows only small, non-polar (lipid,
steroids, etc.) across
on the outer region of phospholipids, polar heads are (hydrophilic/hydrophobic) -
✔️✔️hydrophilic (attracted to water)
on the center region of phospholipids, tails are (hydrophilic/hydrophobic) -
✔️✔️hydrophobic (deterrent of water)
endocrine gland - ✔️✔️structure that synthesizes and secretes hormones into the
blood
exocrine gland - ✔️✔️structure that synthesizes and secretes a product by way of a
duct to an external environment (sweat glands, pancreatic acini)
,tropic hormone - ✔️✔️hormone that regulates production and secretion of another
hormone
(endocrine/exocrine) glands are ductless - ✔️✔️endocrine
types of hormones - ✔️✔️hydrophilic, lipophilic
hydrophilic hormones - ✔️✔️highly soluble in water
types of hydrophilic hormones - ✔️✔️peptide (i.e. insulin), catecholamines (i.e. NE,
Epi)
lipophilic hormones - ✔️✔️highly soluble in lipids
types of lipophilic hormones - ✔️✔️thyroid hormone (derived from tyrosine), steroid
hormones (derived from cholesterol)
peptide hormones are synthesized by endocrine as..... - ✔️✔️any protein that is
destined for export from the cell
processing of steroid hormones - ✔️✔️1) Cholesterol is the precursor for all
steroid hormones
2) Enzymatic reactions modify the side groups on cholesterol
(Specific enzymes are localized to
particular steroidogenic organs/glands)
3) Once formed, steroids immediately diffuse through plasma membrane to reach blood
- (Only cholesterol is stored in significant quantities)
4) Following secretion, some steroid hormones, and thyroid hormone, are changed into
more potent or different hormones
peptide hormones dissolve in .... - ✔️✔️blood
how are steroid/thyroid hormones transported? - ✔️✔️cannot dissolve in blood, bind to
plasma proteins
some plasma proteins only carry _____ lipophilic hormones, while others (albumin) pick
up ____ hormone - ✔️✔️specific, any
transport of catecholamines - ✔️✔️50% circulate as free hormones, 50% bind to
albumin
only (bound/unbound) hormones are active and capable of binding with target cell
receptors, why? - ✔️✔️unbound - ensures large reserve pool to replenish "free" pool
,to induce a response, hormones must bind to.... - ✔️✔️receptors associated with their
target cell
hormone receptor - ✔️✔️protein that recognizes and binds to a specific hormone, can
be on the plasma membrane or inside the cell
target cell - ✔️✔️have receptors for hormone, will change cellular process when
hormone binds
peptides and catecholamines bind with receptors on the target cells.... - ✔️✔️outer
plasma membrane surface - cannot pass through lipid membrane
steroid and thyroid hormones bind to target cells... - ✔️✔️intracellular receptors - easily
penetrate lipid membrane of target cell
hormone functions on target cell by altering the cells proteins in one of two ways.... -
✔️✔️1. hydrophilic hormones activate second messenger pathways to alter the activity
of preexisting intracellular proteins (usually enzymes)
2. lipophilic hormones directly activate gene expression in the target cell forming new
proteins
hormones' effects are proportional to their _____ concentration in the plasma -
✔️✔️free
plasma concentration is under ______ control - ✔️✔️homeostatic
plasma concentration of free (active) hormones depends on what four things? - ✔️✔️1.
rate of secretion into the blood
2. rate of metabolic activation/conversion
3. binding to plasma proteins (lipophilic hormones only)
4. rate of removal by inactivation and excretion in urine
endocrine glands secrete hormones according to what needs? - ✔️✔️homeostatic
negative-feedback control - ✔️✔️output reverses the change in input to maintain
variable near setpoint (ensures that hormone levels don't continue to rise)
endocrine disorders that result from hormone excess or deficiency or decreased target-
cell responsiveness - ✔️✔️hyposecretion, hypersecretion, abnormal target cell
responsiveness, androgen insensitivity syndrome
hyposecretion - ✔️✔️- primary hyposecretion: gland secretes too little hormone
, - secondary hyposecretion: gland secretes too little hormone due to deficiency of its
tropic hormone
hypersecretion - ✔️✔️- primary hyperseretion: gland secretes too much hormone
- secondary hypersecretion: gland secretes too much hormone due to excess of its
tropic hormone
abnormal target cell responsiveness - ✔️✔️target cells do not respond adequately to
the hormone (active free hormone concentration normal or even high)
androgen insensitivity syndrome (AIS) - ✔️✔️unresponsiveness of target cell to
presence of male sex hormones
pituitary gland - ✔️✔️small gland located in bony cavity below hypothalamus,
connected to hypothalamus by a thin stalk
two components of pituitary gland - ✔️✔️- posterior pituitary: neural tissue,
neurosecretory axons
- anterior pituitary: glandular tissue, secrete hormones directly into blood
release of pituitary hormones is controlled by... - ✔️✔️hypothalamus
both hormones released by posterior pituitary are (hydrophilic/hydrophobic) -
✔️✔️hydrophilic
What are the two hormones released from the posterior pituitary? - ✔️✔️vasopressin
(ADH) and oxytocin
vasopressin (ADH) - ✔️✔️released from posterior pituitary, conserves water during
urine formation, causes contraction of arteriolar smooth muscles, release controlled by
hypothalamic osmoreceptors
oxytocin - ✔️✔️released from posterior pituitary, stimulates contraction of uterine
smooth muscle, stimulates milk ejection from mammary glands, other maternal
behaviors
most anterior pituitary hormones are ____ - ✔️✔️tropic
how are anterior pituitary hormones synthesized and released? - ✔️✔️synthesizes and
releases its own hormones into blood
two most important factors that regulate anterior pituitary hormones secretion... -
✔️✔️1. hypothalamic releasing and inhibiting hormones
2. negative feedback by target-gland hormones
