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Week 4 2014 - Solutions
How do hormones change the functioning of cells?
A hormone can change the functioning of cells in a number of ways. They change the type,activities or quantities of proteins produced. They also change the activities of enzymes or bychanging the concentration of enzymes.
Activate certain genes in the nucleus so enzymes produce a particular type of proteins.
Change the shape of structure of an enzyme so it is turned off.
Change the rate of production of an enzyme or structural protein by changing the rate ofreplication (transcription and translation) during protein synthesis.
Explain how steroids work differently from proteins and amines.
Protein and amine hormones attach to receptor molecules on the surface of the target cell. Bycombining with the receptor, this causes a secondary messenger to diffuse through the cell andactivate certain enzymes.
Steroid hormones combine with a receptor protein inside the cell and then activates genes thatcontrol the formation of particular proteins.
Enzyme Amplification.
The process where thousands of enzymes are activated by only one hormone molecule. Thehormone triggers a cascading effect causing more and more enzymes to be activated.
Relationship between hypothalamus & pituitary in terms of their:
Location
Both lie in the brain with the pituitary gland just below the hypothalamus.
the ways in which they function.
The hypothalamus has a duel role – regulating autonomic body functions such as temperaturebut it also produces hormones, most of which get secreted from the pituitary gland.
The pituitary secretes hormones that control other endocrine glands.
The hypothalamus produces hormones that regulate some of the activities of theanterior lobe of the pituitary, those being ACTH and TSH.
The hypothalamus produces ADH and oxytocin that are then released from the posteriorpituitary. These are released after stimulation from the hypothalamus.
Why the pituitary is the master gland and what hormones does it control?
Effect on other Endocrine Glands
Stimulates the development of the follicles that contain eggs, that further stimulates the production of oestrogen.
Helps form the corpus lutuem that then produces oestrogen and progesterone.
In males it stimulates the production of the male sex hormones.
controls the release of hormones from the adrenal cortex.
Hormones from the Posterior Lobe, where do they come from and how do they get there?
The posterior lobe of the pituitary releases oxytocin and ADH. These are both produced in thecells of the hypothalamus. These hormones move down long extensions from thehypothalamus and into the ALP. The release of these hormones are triggered by nerveimpulses initiated in the hypothalamus and conducted along the cell extensions.
What is a target organ?
The pituitary secretes hormones that control other endocrine glands.
How do hormones get from their source to their target organ?
Target organ & function of the following:
Stimulates contraction of the muscles of the uterus. Stimulates the contraction of cells releasing milk during breastfeeding.
Increase permeability of the ducts meaning prepares the body for flight or fight response Controls calcium and phosphate levels in the bloodReduces glucose in the blood by promoting the uptake of glucose into the cells and the Increase blood sugar in blood by converting glycogen to glucose in adipose tissueRegulates the body’s metabolism by What does specificity mean and how is it achieved?
Hormones are only able to influence cells that have the correct receptor for the hormone. Thereceptors consist of chemical structures that only allow specific hormones with specificchemical structures to interact with them.
Why does increasing hormone levels not increase the intensity of the response?
Saturation occurs when all the receptor molecules are filled by hormone molecules and thereforecannot produce any greater effect.
How does EPO increase sporting performance?
EPO builds red blood cells which mean the body has more blood cells and hence can utilise moreoxygen and get rid of more wastes increasing sporting performance.

Source: http://www.warwickscience.info/3A-B%20HBS/Unit%203%20-%20Endocrine%20System/Readings/3HBS%20-%20Endocrine%20System%20%20(Week%204%20Readings).pdf