AQA BIOLOGY PAPER 1 MID-TERM EXAM

AQA BIOLOGY PAPER 1 MID-TERM EXAM What is a relay neurone? - ANSWER-Neurones that carry impulses from the sensory neurone to the motor neurone. What is a motor neurone? - ANSWER-Neurones that carry information from the CNS to the effectors. What is the nervous system? - ANSWER-It is a system that allows you to react to your surroundings. How do signals travel across a synapse? - ANSWER-The chemical or neurotransmitter diffuses across the synapse and binds to a complementary receptor on the neurone (postsynaptic). This causes an electrical impulse to travel down the next neurone. What is a synapse? - ANSWER-A gap between two neurones. What is the thermoregulatory centre of the brain? - ANSWER-Near the hypothalamus, monitors the temperature of blood. Describe the stages in a reflex arc. - ANSWER-Stimulus-Receptor-sensory neurone CNS (relay neurone) - motor neurone - effector - response Name responses that reduce body temperature. - ANSWER-Hairs lie flat, sweat and blood vessels get wider(vasodilation) What happens during vasodilation? - ANSWER-The blood vessels supplying the skin dilate (widen). This helps to transfer energy to the environment. Name responses that increase body temperature. - ANSWER-Hairs stand up, no sweat, shivering and blood vessels constrict(vasoconstriction) What happens during vasoconstriction? - ANSWER-The blood vessels supplying the skin constrict to close off the skins blood supply. What is the body's core temp? - ANSWER-37 degrees Celsius What are hormones? - ANSWER-Chemical messengers that travel in the blood to target organs. What is homeostatsis? - ANSWER-The maintenance of a constant internal environment. What is a stimulus? - ANSWER-A change in your environment than requires a response. e.g Light, sound, touch, pressure, pain, chemical or temperature.