1. LIFE SCIENCES 2011 J Gerber and J Goliath1

2. Hormones and nerves enable animals to:  Respond to internal and external change  Co-ordinate the various activities of the body  Observations of the response of some invertebrates e.g wood lice, to light and humidity J Gerber and J Goliath2

3. The need for a nervous system in humans in terms of:  Reaction to stimuli (external and internal)  Co-ordination of various activities of the body J Gerber and J Goliath3

4. Location and functions of :  Cerebrum  Hypothalamus  Cerebellum  Medulla oblongata  Spinal cord  Model of human brain  Observe and draw the external structure of the brain J Gerber and J Goliath4

5.  Dagga  Heroin  Ecstacy  Tik J Gerber and J Goliath5

6. Peripheral nervous system  Location and function Autonomic nervous system  Location and function J Gerber and J Goliath6

7.  Causes, symptoms, treatment of ONE of the following diseases/disorders of the nervous system:  Alzheimer’s Disease OR  Attention Deficit Disorder OR  Depression J Gerber and J Goliath7

8.  Generalised structure of a neuron including: nucleus, cell body, cytoplasm, myelin sheath, axon and dendrites  Labelled drawings to show the three types of neurons from microscope slides or micrographs  Structure and functions of the three types of neurons  The nerve is composed of nerve fibres held together by connective tissue  Transmission of nerve impulses along neurons and across synapses using neurotransmitters (no detail of electrical charges needed) J Gerber and J Goliath8

9.  Difference between reflex arc and reflex action  Observe microscope slides and draw and LABEL the cross section through the spinal cord  Structure of a simple reflex arc (receptor, sensory neuron, dorsal root of spinal nerve, spinal cord, interneuron, motor neuron, ventral root of spinal nerve, effector)  Functioning of the reflex arc, use an example  Significance of a reflex arc J Gerber and J Goliath9

10.  Receptors on the skin of wood lice are sensitive to humidity and light  Wood lice move away from light and dry environments J Gerber and J Goliath10

11. The systems below work together to respond to external and internal changes:  Nervous system  Endocrine system (hormones) J Gerber and J Goliath11

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13. Location  Largest part of the brain is situated in the skull. Functions  Centre of all voluntary actions  Contains areas that receive and interpret nerve impulses from the sense organs for the sensation of smell, sound, sight, taste and touch.  Centre of higher mental functions e.g memory, intelligence, emotions etc. J Gerber and J Goliath13

14. Location  Situated under the thalamus. Functions  Reflex control centre of mechanisms such as temperature, blood pressure, sleep and emotion  Produces certain hormones e.g. ADH which assist in maintaining water balance  Control centre for homeostasis J Gerber and J Goliath14

15. Location  Situated behind and underneath the cerebrum Functions  Controls the co-ordination of voluntary movements  Contain the centres which control balance and equilibrium J Gerber and J Goliath15

16. Location  Forms bottom part of the brain stem and is an extension of the spinal cord Functions  Transmitter of impulses between brain and spinal cord  Controls autonomic functions e.g. breathing, heartbeat, peristalsis, widening and narrowing of blood vessels J Gerber and J Goliath16

17. Location  Extends from the medulla oblongata through the vertebral canal to the lumber region Functions  Provides a pathway for nerve impulses to and from the brain  Contains reflex centres that initiate reflex actions J Gerber and J Goliath17

18. Dagga  Chemical substance in dagga combines with specific receptors (memory, concentration, movement) in the brain and inhibits the normal functioning of these receptors. Heroin  Has a depressive affect on the CNS, slows down breathing and suppresses pain. J Gerber and J Goliath18

19. Heroin  This drug has a depressive effect on the CNS, slows down breathing and suppresses pain.  Inhibits the activity of the medulla oblongata. J Gerber and J Goliath19

20. Ecstacy  Causes an excessive release of a certain neurotransmitter which over stimulates brain neurons which causes damage to the terminal branches of the axons  Negative effect on the emotions, memory and ability to learn. J Gerber and J Goliath20

21. Tik  Has a stimulating effect on the CNS e.g. accelerated breathing and heart rate.  Causes an excessive release of a certain neurotransmitter which over stimulates neurons in the brain and damage these neurons J Gerber and J Goliath21

22. Location  Nervous tissue found outside the CNS and is subdivided into the somatic and autonomic nervous systems. Consist of 12 pairs of cranial nerves and 31 pairs of spinal nerves Functions  Conduct nerve impulses from the receptors to the CNS, along the sensory neurons  Conduct nerve impulses from the CNS to the effectors, along the motor neurons J Gerber and J Goliath22

23. Location  Consists of nerves which are connected to the CNS. Consists of the following systems i.e. sympathetic and parasympathetic. Functions  Controls all involuntary actions.  Conducts nerve impulses from the CNS to the effectors e.g. muscles and glands.  Sympathetic system prepares the body for emergency.  Parasympathetic system allows the body to return to normal after stimulation by the sympathetic system – antagonistic. J Gerber and J Goliath23

24.  Same basic structure as any other cell.  Cell body consists of cytoplasm and a nucleus.  Cytoplasm contains Nissl granules which are rich in RNA and play a role in protein synthesis.  Two types of outgrowths – dendrites and axons.  Dendrites conduct nerve impulses to the cell body.  Axons conduct impulses away from the cell body.  Axons are surrounded by a myelin sheath for protection. J Gerber and J Goliath24

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26.  Neurons are classified based on the number of outgrowths projecting from the cell body. Structure of different neurons  Monopolar neurons – one outgrowth that branches into two, i,e, one dendrite and one axon.  Bipolar neurons – two outgrowths, i.e. a dendrite and axon.  Multipolar neurons – many outgrowths, a number of dendrites and one axon. J Gerber and J Goliath26

27.  Neurons are classified according to their function as follows:  Sensory or afferent neurons – conduct impulses from the receptors to the CNS and are mostly monopolar.  Motor of efferent neurons – conduct impulses from the CNS to the effectors and are multipolar.  Interneurons or connector neurons – connect sensory and motor neurons in the CNS and are multipolar. J Gerber and J Goliath27

28.  Neurons are bundled together in the human body.  Small bundles of axons are called nerve fibres.  Nerve fibres are bundled together with some connective tissue.  Nerve fibres and connective tissue make up nerve tissue. J Gerber and J Goliath28

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30.  Neurons are interconnected to form a continuous conduction system throughout the body.  The axon of one neuron connects with the dendrites of the next neuron.  Successive neurons are not directly connected to each other, but seperated by a small gap.  A physiological (functional) connection is formed known as a synapse.  The gap is called the synaptic cleft. J Gerber and J Goliath30

31.  A receptor is stimulated by a change in the environment and produces impulses.  Dendrites of a sensory neuron conduct these nerve impulses to the cell body.  Nerve impulses are conducted from the cell body along a single axon to the terminal branches.  Ends of terminal branches do not touch the dendrites of the neurons in the spinal cord because of a gap.  Ends of terminal branches of axons contain neurotransmitters which are released into the synapse when the terminal branches of axons are stimulated by an incoming impulse.  Neurotransmitters play a role in the transmission of nerve impulses. J Gerber and J Goliath31

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33.  Reflex action – a quick, automatic movement/action by an effector, in response to a stimulus received by a recepto.r  Reflec arc – pathway along which nerve impulses are carried from a receptor to an effector to bring about a reflex action. J Gerber and J Goliath33

34.  Receptor – detects a stimulus and converts into a nerve impulse.  Sensory neuron – conducts the nerve impulse to the grey matter of the spinal cord.  Interneuron – serves as a reflex centre in the grey matter of the spinal cord and conducts nerve impulses from the sensory neuron to the motor neuron.  Motor neuron – conducts the nerve impulses from the spinal cord to the effector.  Effector – reacts to the original stimulus. J Gerber and J Goliath34

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36.  Heat stimulus received by a receptor and convert into a nerve impulse.  Nerve impulse is transmitted by the sensory neuron through the dorsal root of spinal cord.  Sensory nerve transmits the impulse to the interneuron in grey matter of spinal cord.  Neuron is connected synaptically to the motor neuron.  Axon of the motor neuron transmits the impulse through the ventral root to the effector. J Gerber and J Goliath36

37.  Reflex arcs protect the body from dangerous situations from the external environment. J Gerber and J Goliath37

38. QUESTION 1 Tommy was keeping his finger over a burning candle. In about 0,2 seconds he pulled his finger away. 1.1What type of action is Tommy’s reaction? 1.2Explain your answer to QUESTION 1.1 J Gerber and J Goliath38

39. QUESTION 1.3 Diagram 1 below shows a cross section through Tommy’s spinal cord. Diagram 2 shows Tommy’s finger over the burning candle and a muscle in his arm. Draw the missing parts/structures and also indicate the path (use different colours if possible) followed by the impulse during the reaction named in QUESTION 1.1. J Gerber and J Goliath39

40. 1.1 Reflex 1.2 Reaction was quick/sudden; without even thinking about it/autonomic. 1.3 J Gerber and J Goliath40