Hormones and the Endocrine system Flashcards
List six differences between communication in the nervous and endocrine systems
Nervous - fast - uses a neurotransmitter to transfer messenger - Short effect - Targets muscle and glandular tissue - Short distance from target across synapse Endocrine - Slow reaction time - uses a hormone messenger - duration of effects is long - Targets all body cells and tissues - Cells producing messenger is endocrine gland cells or modified nerve cells
Define hormone
Are chemical substances that affect the activity of another part of the body (target site)
Describe the three components of endocrine control pathways
Receptor- detects stimulus
Control centre - receives information from receptor
Effector - generates the appropriate response
Why do some cells respond to a particular hormone in the bloodstream while others don’t?
This is because only target cells have the specific receptor protein to recognise that particular hormone
How does the hypothalamus integrate the nervous and endocrine systems in vertebrates?
Receives information from nerves around the body and brain and initiates endocrine signals
In response to these signals, the hypothalamus releases neurohormones into the blood which have effects elsewhere in the body.
Why is the posterior pituitary called the neurohypophysis and what does it do?
because it is composed of nervous (brain) tissue; it is not a true gland, but a place of temporary storage for hormones synthesised in the brain
Define tropic hormones and describe the two different types of tropic hormones released by the hypothalamus that act on the anterior pituitary.
which are hormones that regulate the function of other endocrine cells such as those found in the AP
releasing hormones that stimulate the AP to release hormones and inhibiting hormones that inhibit the AP’s hormone release.
How do neurohormones differ from ‘classic’ hormones? How are they similar?
Neuroendocrine system
Specialized neurons are capable of synthesizing, storing and releasing hormones into body fluids.
Hormones are released from specialized non-neural tissue into body fluids. Classical endocrine glands are found only in higher invertebrates (some molluscs) and vertebrates.
How does the nervous system contribute to moulting in insects?
When JH concentration is high, ecdysone induces moulting resulting in a bigger larva (JH suppresses metamorphosis into adult). When JH concentration is low, ecdysone induces moulting resulting in metamorphosis of adult
Juvenile hormone is sometimes used commercially as an insecticide. What effects does it
have on insect populations? Explain.
This hormone promotes retention of juvenile/larval characteristics, suppressing metamorphosis to adult stage
