LU9: HORMONES AND ENDOCRINOLOGY
LU9: HORMONES AND ENDOCRINOLOGY
Blood transfers hormones
to whole body.
Hormone reaches target tissue and bind to specific receptor.
Gland secrete hormones into extracellular fluid.
Target tissue responds and resulted in
Hormones produced by
Feedback reach gland to either stop or increase production of hormones.
Hormones Regulation in Insect
induces molting in moth.
Juvenile hormone (JH)
: Promotes retention of larval characteristic (secreted by a pair of small gland/corpora allata)
BH stimulates protoracic gland
(produced by Neurosecretory) to secrete ecdysone.
JH balances the effect of BH and ecdysone
Caused by endocrine disease/drugs interaction and can result in serious medical condition (if left untreated)
Symptoms include behavioral, physical or physiological changes.
Unusual level of hormones in bloodstream can leads to hormone disorder.
: Iodine deficiency causes thyroid to enlarge as it tries to produce thyroxine
Control & Feedback
: Changing blood levels of certain ions stimulate hormone release.
: Nerve impulses stimulate hormone release (Most are under control of the sympathetic nervous system)
: Endocrine glands are activated by other hormones
Endocrine gland hypersecretion
(leading to hormone excess)
Endocrine gland hyposecretion
(leading to hormone deficiency)
(benign or malignant)
of endocrine glands
Classes of Hormones
(large proteins + carbohydrate: eg., FSH, LH)
(modified amino acids: eg., epinephrine, melatonin)
(small proteins: eg, insulin, ADH)
Hydrophilic & not lipid soluble
(can't diffuse across membrane)
Trigger secondary (2°) messenger pathway
(signal transduction & multi-step "cascade")
Activate cellular response
(enzyme action, uptake or secretion of molecules, etc.)
(modified cholesterol: eg., sex hormones, aldosterone)
(diffuse across membrane & enter cells)
Bind to receptor proteins (cytoplasm) & then hormone-receptor complexes moves into nucleus.
Bind to receptor proteins (nucleus) & then bind to DNA (as transcription factors)
(result in synthesis of new proteins)
Endocrine & Nervous Signaling links
("master control center")
Nervous system (receives information from nerves around body about internal conditions)
Regulates release of hormones from pituitary
Endocrine system (secretes broad range of hormones regulating other glands)
Hormones Feedback Mechanism
Stimulus triggers control mechanism that inhibits further (body temperature, sugar metabolism)
blood glucose, blood osmolarity, blood calcium, metabolism & growth
Stimulus triggers control mechanism that amplifies effect (lactation, labor contractions)
milk productions, frog metamorphosis
: System of ductless glands (Each gland contain specialized cells that synthesizes Hormone)
Endocrine vs Exocrine
: Ductless, Blood stream, & Hormone
: Ducts, Lumen and surfaces, and Eg: enzyme & sweat
Endocrine vs Nervous Signaling
blood circulation to whole body
slow, long-lasting response
neuron network to target cells
fast, short-lasting response
electrical + chemical
(nervous impulse + neurotransmitter)
Caused by excessive concentration thyroxine-a thyroid hormone in the bloodstream
: Weight loss despite increase in appetite, increased activity level, rapid heart rate, increased urination, diarrhea, aggression, nervousness
(common glandular disorder in cats)
Prolonged exposure of cortisol leads to hypercortisolism
shows collection of external sign or symptom related to cortisol imbalance
: A chemical signal that secreted into body fluid (often blood), & communicate regulatory messages within the body.
Coordinate the organs through action and feedback
metabolism, growth, development, maturation, reproduction
A method of communication between one body part to another