14/09/2015 Brain and Mind (OCR)

14/09/2015 The Nervous System The CENTRAL NERVOUS SYSTEM (CNS) enables us to react to our surroundings. It consists mainly of the brain, the spinal chord, nerve cells (“neurones”) and receptors. Types of receptor: 1)Light receptors in the eyes 2)Sound receptors in the ears 3)Taste receptors on the tongue 4)Smell receptors in the nose 5)Touch, pressure and temperature receptors in the skin 6)Changes of position receptors in the ears (balance)

14/09/2015 Nervous Reactions When we react to a stimulus our bodies use the following pattern: Stimulus Receptor Coordinator Effector Response For example, consider a man and a camel: Oh No! What are the stimulus, receptor, coordinator, effector and response in this situation?

14/09/2015 Examples of reactions StimulusReceptor (i.e. the thing that detects the stimulus) Effector (i.e. the thing that will do the reaction) Response (i.e. action taken) Bright light Sour taste Losing balance Sit on a drawing pin

14/09/2015 Types of nerve cell (“neuron”) NucleusMuscle strands (effector) Axon 1) Motor neurone2) Sensory neurone3) Relay neurone Impulse Nerve cells (neurons) are elongated with branched endings to connect to many muscles fibres. Fatty sheath

14/09/2015Synapses Neurones never ____ each other – there is a small gap between them called a _____. A signal is sent from one _______ to the next by a _______ transmitter across the synapse (called a “neurotransmitter”). These transmitters are then ________ back into the sensory neurone to be used again. Children have around 1000 trillion synapses whereas adults only have between 100 and 500 trillion. Words – chemical, synapse, neurone, touch, reabsorbed

14/09/2015 Conscious actions A conscious action is one where the brain makes a considered response. Here’s what happens: Stimulus Receptor Sensory Neurone Coordinator Motor Neurone Effector Response 1) Receptors in your skin detect a stimulus 3) Here another sensory neurone carries the signal to the brain 4) The brain decides to move away the hand 5) This impulse is sent by MOTOR NEURONES to the hand muscles (the effectors) via the spinal chord… 2) The impulse is carried by SENSORY NEURONES to the spinal chord 6) Which then moves the hand away

14/09/2015 Reflex actions Sometimes conscious action is too slow to prevent harm, e.g… In situations like this the body bypasses the brain to produce a quicker response. Here’s how it works…

14/09/2015 Reflex actions 1. Receptor2. Sensory neurone 3. Relay neurone in the spinal chord 4. Motor neurone 5. Effector

14/09/2015 Simple reflexes in humans Babies can demonstrate simple reflexes: 1)Stepping reflex 2)Startle (or moro) reflex 3)Grasping reflex 4)Rooting reflex 5)Sucking reflex

14/09/2015 The Iris Reflex When the light is bright the radial muscles relax, the circular muscles contract and the pupil increases in size. When the light is bright the radial muscles _____, the circular muscles _______ and the pupil ________ in size.

14/09/2015 Conditioned reflexes - Pavlov’s Dog Ivan Pavlov, I won the Nobel Prize in 1904 and am most famous for investigating “conditioned responses”: 1)Steak + dog = saliva 2)Steak + bell + dog = saliva 3)Bell + dog = saliva

14/09/2015 Complex Behaviour When the brain is asked to do certain tasks different areas are “activated”. New experiences cause new neuron pathways to develop, while pathways that are not used are eventually destroyed. This is why we become better at certain tasks when we practice them more often. PET scan showing areas “activated” by doing algebra.

14/09/2015 Feral children 1. What does the term “Feral children” mean? 2. what has caused their condition and what are the consequences?

14/09/2015 The Cerebral Cortex By studying the effects (e.g. memory/sight loss) when different parts of the brain are damaged scientists have been able to identify which parts of the brain control which functions.

14/09/2015 Other techniques of studying the brain 1) An electroencephalogram (EEG) is a visual record of the electrical activity generated by neurons in the brain. It works by amplifying and detecting the electrical signals from the brain. 2) Magnetic resonance imaging (MRI) scanning is a new technique that produces images of different cross sections of the brain and uses colours to represent activity.

14/09/2015Memory Our memory is divided into two types: short term and long term. Short term memory is capable of storing a limited amount of information for a limited amount of time. Long term memory is when more information is stored over a much longer time. Ways of improving short term memory, e.g. a phone number Ways of improving long term memory e.g. exam revision

Information Processing Model of Memory 14/09/2015

B6 Revision Google – type in GCSE BITESIZE Select from the ‘Additional Science’ section OCR Additional Science Select from the ‘Biology’ section ‘Brain and Mind’ Use the information from this site to write definitions for the following key words 14/09/2015

B6 Key words Serotonin Stimulus Receptor Synapse Motor Neurone 14/09/2015 Sensory Neurone Reflex Effector Central Nervous System Peripheral Nervous System Involuntary Conditioned Response Behaviour

14/09/2015 The Effect of Drugs Drugs can have different effects on the nervous system. For example, alcohol _____ reactions down by affecting chemical transmitters in the brain whereas caffeine causes nerve impulses to be sent ______, thereby _______ reaction time. Serotonin is a neurotransmitter in the central nervous system that is associated with feeling ____. The drug ecstasy blocks the synapses where the serotonin is removed, making the feeling last longer. However, the neurons are harmed in this process and taking ecstasy can lead to long term _____ loss. Words – memory, slows, increasing, faster, happy