Animal responses to the environment

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Animal responses to the environment. LIFE SCIENCES 2011. Human nervous system. Hormones and nerves enable animals to: Respond to internal and external change Co-ordinate the various activities of the body - PowerPoint PPT Presentation

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  • LIFE SCIENCES2011J Gerber and J Goliath*

    J Gerber and J Goliath

  • Hormones and nerves enable animals to:

    Respond to internal and external changeCo-ordinate the various activities of the bodyObservations of the response of some invertebrates e.g wood lice, to light and humidity

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • The need for a nervous system in humans in terms of:

    Reaction to stimuli (external and internal)

    Co-ordination of various activities of the bodyJ Gerber and J Goliath*

    J Gerber and J Goliath

  • Location and functions of :CerebrumHypothalamusCerebellumMedulla oblongataSpinal cordModel of human brainObserve and draw the external structure of the brain

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • DaggaHeroinEcstacyTikJ Gerber and J Goliath*

    J Gerber and J Goliath

  • Peripheral nervous systemLocation and function

    Autonomic nervous systemLocation and function

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • Causes, symptoms, treatment of ONE of the following diseases/disorders of the nervous system: Alzheimers Disease ORAttention Deficit Disorder ORDepression

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • Generalised structure of a neuron including: nucleus, cell body, cytoplasm, myelin sheath, axon and dendritesLabelled drawings to show the three types of neurons from microscope slides or micrographsStructure and functions of the three types of neuronsThe nerve is composed of nerve fibres held together by connective tissueTransmission of nerve impulses along neurons and across synapses using neurotransmitters (no detail of electrical charges needed)J Gerber and J Goliath*

    J Gerber and J Goliath

  • Difference between reflex arc and reflex actionObserve microscope slides and draw and LABEL the cross section through the spinal cordStructure 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 exampleSignificance of a reflex arc

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • Receptors on the skin of wood lice are sensitive to humidity and light

    Wood lice move away from light and dry environmentsJ Gerber and J Goliath*

    J Gerber and J Goliath

  • The systems below work together to respond to external and internal changes:

    Nervous system

    Endocrine system (hormones)J Gerber and J Goliath*

    J Gerber and J Goliath

  • J Gerber and J Goliath*

    J Gerber and J Goliath

  • LocationLargest part of the brain is situated in the skull.FunctionsCentre of all voluntary actionsContains 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 Goliath*

    J Gerber and J Goliath

  • Location

    Situated under the thalamus.

    FunctionsReflex control centre of mechanisms such as temperature, blood pressure, sleep and emotionProduces certain hormones e.g. ADH which assist in maintaining water balanceControl centre for homeostasisJ Gerber and J Goliath*

    J Gerber and J Goliath

  • Location

    Situated behind and underneath the cerebrumFunctions

    Controls the co-ordination of voluntary movementsContain the centres which control balance and equilibriumJ Gerber and J Goliath*

    J Gerber and J Goliath

  • Location

    Forms bottom part of the brain stem and is an extension of the spinal cordFunctions

    Transmitter of impulses between brain and spinal cordControls autonomic functions e.g. breathing, heartbeat, peristalsis, widening and narrowing of blood vesselsJ Gerber and J Goliath*

    J Gerber and J Goliath

  • Location

    Extends from the medulla oblongata through the vertebral canal to the lumber regionFunctions

    Provides a pathway for nerve impulses to and from the brainContains reflex centres that initiate reflex actionsJ Gerber and J Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • 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 neuronsJ Gerber and J Goliath*

    J Gerber and J Goliath

  • 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 neuronsConduct nerve impulses from the CNS to the effectors, along the motor neurons

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • LocationConsists of nerves which are connected to the CNS. Consists of the following systems i.e. sympathetic and parasympathetic.FunctionsControls 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 Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • J Gerber and J Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • J Gerber and J Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • J Gerber and J Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • J Gerber and J Goliath*

    J Gerber and J Goliath

  • 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 Goliath*

    J Gerber and J Goliath

  • Reflex arcs protect the body from dangerous situations from the external environment.J Gerber and J Goliath*

    J Gerber and J Goliath

  • InstructionsExplanation of activity on a reflex arc.After 10 minutes each pair/group/individual give feedback.

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • 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 Tommys reaction?1.2Explain your answer to QUESTION 1.1

    J Gerber and J Goliath*

    J Gerber and J Goliath

  • QUESTION 1.3Diagram 1 below shows a cross section through Tommys spinal cord. Diagram 2 shows Tommys 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 Goliath*

    J Gerber and J Goliath

  • 1.1 Reflex

    1.2 Reaction was quick/sudden; without even thinking about it/autonomic.1.3J Gerber and J Goliath*

    J Gerber and J Goliath

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