HYPOTHALAMUS AND THE ADRENAL GLANDS P2 (Version 1) (Full time) Feb-Mar 2012 – Q4.3 Describe the role of the hypothalamus and the adrenal glands in bringing changes to the blood vessels of the human skin and explain why these changes take place Possible answer HYPOTHALAMUS - The change in temperature is detected by the thermoreceptors in the skin - The stimulus is converted to a nerve impulse - Which is transmitted to the hypothalamus - The hypothalamus sends impulses to the muscle layer in the arterioles of the skin (Max 3) - ON A COLD DAY the arterioles close to the surface constrict/vasoconstriction occurs - Less blood flows to capillaries close to the surface - Sweat production decreases / less sweat is lost - less heat is radiated from the body/less heat is lost - ON A HOT DAY the arterioles close to the surface dilate/ vasodilation occurs - More blood flows to the capillaries close to the surface - Sweat production increases/ more sweat is lost - More heat is radiated from the body/more heat is lost ADRENAL GLAND The adrenal gland secretes adrenalin Adrenalin is the hormone that prepares the body to cope with emergency/danger /stress situations Adrenalin causes the blood vessels of the skin to constrict• Less blood flows to the surface of the skin Because the skin is not an important organ during an emergency Re-directing more blood /more oxygen and food to vital organs To enable the body to respond during an emergency (Max 6) SYTHESIS 3 Well structured - demonstrates insight and understanding of question 2 Minor gaps in the logic and flow of the answer 1 Attempted but with significant gaps~ in the logic and the flow of the answer 0 Not attempted/nothing written other than the question number
Posted on: Thu, 24 Jul 2014 19:16:59 +0000
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