Studied by 22 peopletarget receptors
what do hormones and other signalling molecules bind to triggering specific response pathways
feedback regulation and coordination
what in the nervous system is common in the endocrine system
circulatory system
where are hormones (chemical signals) secreted into to communicate regulatory messages
endocrine and nervous system
the two systems that coordinate communication throughout the body
endocrine system
system that secretes hormones that coordinate slower but longer acting responses
nervous system
system that conveys high-speed electrical signals along specialized cells called neurons through dedicated pathways (signals regulate other cells)
type of secreting cell, route taken by a signal in reaching its target
The ways signals are transmitted between animal cells are classified by which two criteria
maintains homeostasis, regulates growth and development, mediates responses to stimuli
responsibilities of endocrine system
bloodstream
how do the hormones that are secreted into the extracellular fluid by endocrine cells reach to targets
local regulators
molecules that act over short distances and reach target cells only by diffusion
paracrine signalling
the target cells lie near the secreting cells & of different type
autocrine signalling
the target cell is also the secreting cell and/or the same type of cell
synaptic signalling
neurons form specialized junctions with target cells called synapses (paracrine is a muscle, autocrine if neuron)
neurotransmitters
at synapses, neurons secrete __ that diffuse short distances and bind to target cell receptors
neuroendocrine signalling
type of signalling where specialized neurosecretory cells secrete neurohormones that travel to target cells via the bloodstream
pheromones
used by members of animal species to communicate; are chemicals that are released into the environment
polypeptides, amines from amino acids, steroid hormones
three major classes of hormones in vertebrates
lipid soluble hormones
pass easily through cell membranes (steroid hormones)
water-soluble hormones
dont pass easily through the cell membrane (polypeptides and amines)
gas
Many cells can produce this that have local signalling effects due to their small size and lack of charge which allows for them to diffuse freely
proteins
many of the most familiar hormones are __ encoded by genes (insulin, growth factors)
amine hormones
hormones that are signalling factors produced from amino acids (neuronal signalling factors)
water-soluble hormones
hormones that are secreted by exocytosis, travel freely in the bloodstream, and bind to cell surface receptors
lipid soluble hormones
diffuse across cell membranes, travel in bloodstream bound to transport proteins, diffuse through membrane of target cell and bind to receptors in the cytoplasm or nucleus
signal transduction pathway
binding of a hormone to its receptor leads to what
epinephrine
multiple effects in mediating the bodys response to short term stress; can trigger a pathway which breaks down glycogen which released glucose into bloodstream
change in gene expression
what is the usual response to lipid-soluble hormones
type of receptor and signal transduction pathway
same hormones can have different effects on cells depending on what
thyroid hormones
hormones that regulate metabolism in vertebrates; also control the metamorphosis of the larva into adult in frogs
endocrine glands
where the endocrine cells are often grouped into ductless organs(thyroid, parathyroid, testes, ovaries); these secrete hormones directly into surrounding fluid
exocrine glands
(salivary glands) ducts which carry secreted substances onto body surfaces or into body cavities
regulatory pathways
hormones are assembled into __ __
positive feedback loop
reinforces a stimulus to produce an even greater response (oxytocin)
negative feedback loop
loop inhibits a response by reducing the initial stimulus, thus preventing excessive pathway activity
simple neuroendocrine pathway
In a simple neuroendocrine pathway, the stimulus is received by a sensory neuron, which stimulates a neurosecretory cell The neurosecretory cell secretes a neurohormone, which enters the bloodstream and travels to target cells
oxytocin
released from the posterior pituitary due to nerve impulses from the hypothalamus
ecdysteroid
found in invertebrates where when in presence of juvenile hormone, moulting is promoted, but in absence of JH, the development of adult characteristics
posterior hypothalamus
which part of the hypothalamus stores and secretes hormones
hypothalamus
what plays a central role in integrating the endocrine and nervous systems
pituitary gland
is attached to the hypothalamus and has a posterior and anterior side
nervous, endocrine
The hypothalamus receives information from the __ system and initiates responses through __ signalling
posterior pituitary
the extension of the hypothalamus which stores and secretes hormones the hypo
anterior pituitary
extension of the hypothalamus which makes and releases hormones under the regulation of the hypothalamus
oxytocin, antidiuretic hormone
two hormones released from the posterior pituitary that act on nonendocrine tissue
oxytocin
regulates milk secretion by mammary glands
releasing and inhibiting
Hormone production in the anterior pituitary is controlled by __ and __ hormones secreted from the hypothalamus
tropic hormones
many anterior pituitary hormones act as __ __; regulate function of other endocrine cells or glands
thyroid hormone
a hormone that in humans and other mammals regulates many functions
thyroropin-releasing hormone (TRH)
what is released by the hypothalamus when thyroid levels are low
thyroid stimulating hormone (TSH)
secreting by anterior pituitary when TRH is released
Hypothyroidism
too little thyroid function, can lead to symptoms such as Weight gain, lethargy, cold intolerance
Hyperthyroidism
excessive production of thyroid hormone, can lead to High temperature, sweating, weight loss, irritability, and high blood pressure
Malnutrition
(e.g., iodine deficiency) can alter thyroid function (e.g., disruption of negative feedback loop)
growth hormone (GH)
the hormone that is secreted by the pituitary gland that has tropic and nontropic effects; promotes growth directly
parathyroid hormone (PTH), calcitonin
the two antagonistic hormones that regulate the homeostasis of calcium
parathyroid glands
what released parathyroid hormones
thyroid gland
what released calcitonin
increases level of blood Ca2+
what does PTH do
decreases level of blood Ca2+
what does calcitonin do
adrenal medulla (inner portion), adrenal cortex (outer portion)
two glands of the adrenal gland
epinephrine and norepinephrine
what two things does the adrenal medulla secrete
corticosteroids
the adrenal cortex releases what after reacting to endocrine signals
corticosteroids, glucocorticoids
what two corticosteroids are produced from the hormone cascade pathway
Note 
Flashcard (28)