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GCSE Biology 1AHuman Biology KEYWORDS KEYWORDS ( Write these into your journal book and find the definition as part of your weeks homework) Gland, Hormone,

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Presentation on theme: "GCSE Biology 1AHuman Biology KEYWORDS KEYWORDS ( Write these into your journal book and find the definition as part of your weeks homework) Gland, Hormone,"— Presentation transcript:

1 GCSE Biology 1AHuman Biology KEYWORDS KEYWORDS ( Write these into your journal book and find the definition as part of your weeks homework) Gland, Hormone, Impulse, Nervous system, Effector, Stimulus, Receptor, Neurone, Synapse

2 GCSE Biology 1AHuman Biology Name the hormones – Using Figure 2 on page 24 of the Student Book, write down the names of the hormones secreted by the glands shown on the diagram. Time: 10 minutes Working Groups: Your choice of 1, 2 or 3 STARTER

3 GCSE Biology 1AHuman Biology STARTER continued Name the hormones – Have you thought of any others? Time: 10 seconds to add them to your list

4 GCSE Biology 1AHuman Biology STARTER answers Pituitary gland – FSH, LH (stimulates the release and maturity of follicles during menstruation) Thyroid gland – Thyroxine (regulates the rate of metabolism) Adrenal gland - corticosteroids and catecholamines including cortisol and adrenaline and small amounts of testosterone (regulates stress levels) Pancreas – peptides (regulates the production of shorter active digestive enzymes) Ovary – oestrogen, progesterone and small amounts of testosterone (regulates the growth of eggs and stabilises the growing foetus during pregnancy) Testis – testosterone (plays a key role in the health and well-being of the man)

5 GCSE Biology 1AHuman Biology I AM LEARNING TO understand how the body is controlled I WILL LEARN THAT The nervous system enables humans to react to their surroundings and coordinate their behaviour. Receptors detect stimuli which include light, sound, changes in position, chemicals, touch, pressure, pain and temperature. Information from receptors passes along cells (neurones) in nerves to the brain. The brain coordinates the response. Many processes in the body are coordinated by chemical substances called hormones. Hormones are secreted by glands and are transported to their target organs by the bloodstream. I CAN Explain how the body control’s its functions and responses through hormones (chemicals) and nerves (electrical impulses) LEARNING OBJECTIVES

6 GCSE Biology 1AHuman Biology Identification of the density of nerve endings Identification of the density of nerve endings – AIM: To investigate the sensitivity of different areas of the skin. Method: 1.Working in pairs, one student looks in a different direction, while another student touches them on the back of the hand with either one or two pieces of blunt pencil about 1 cm apart. 2.The blindfolded student has to say whether it was one point or two points that touched them. 3.Place a cross on the hand for each point felt. Results: Map the density of sensory receptors by drawing it into your book. Conclusion: Are the receptors in groups? Or randomly placed? What can you say about the density of the receptors identified?

7 GCSE Biology 1AHuman Biology CONTROL SYSTEMS There are two main control systems in your body. 1.Nervous system 1.Nervous system – which has two main sections central or CNScentral or CNS that is made up of the spinal cord and brain and functions to coordinate all actions of the body peripheral or PNSperipheral or PNS that is made up of the bodies nerves and functions to connect the CNS to the rest of the body through neurones. PNS is further divided into –somatic or SNS –somatic or SNS which is associated with the voluntary control of body movements and is made up of all neurones, sense organs, skin, skeletal muscles –Autonomic or ANS –Autonomic or ANS which is associated with the involuntary control of body movements such as reflex and controls such things as heart rate, body temperature, digestion etc. The ANS is further divided into »Parasympathetic nervous system »Parasympathetic nervous system works in actions that do not require a fast response (fight or fight response) »Sympathetic nervous system »Sympathetic nervous system works in actions that do require a fast response (rest and digest response) 2.Endocrine system 2.Endocrine system – which is a system of glands that release a number of signalling chemicals known as hormones.

8 GCSE Biology 1AHuman Biology Say what? NERVOUS SYSTEM CNS PNS ANS SNS ParasympatheticSympathetic Nervous system Nervous system releases electrical impulses that are quick but the effects are short lived and it involves the CNS (either just spinal cord or both spinal cord and brain) messages are carried by neurones Endocrine system Endocrine system releases chemical signals that are slow to react but the effects are long lasting. This does not involve the CNS. Messages are carried by the blood.

9 GCSE Biology 1AHuman Biology

10 GCSE Biology 1AHuman Biology Parts of the nervous system nervous system The nervous system is made up of three main parts; The brain The spinal cord Nerve fibres stimuli It detects stimuli such as light, sounds, temperature, pressure, pain and co-ordinates the bodies response.

11 GCSE Biology 1AHuman Biology Parts of the nervous system For example; If you smell something burning… receptorstimulusYour nose (receptor) detects the stimulus (smell) Nerve fibresbrainNerve fibres send the message to the brain brainYour brain then sends a message to move your body away or to put out the fire! SIMPLES RIGHT! SIMPLES RIGHT!

12 GCSE Biology 1AHuman Biology Lets look at some bits more closely RECEPTORS Receptors are sensors on the body that detect stimuli electrical signalsThey convert stimuli into electrical signals (messages) called impulses.

13 GCSE Biology 1AHuman BiologyEFFECTORS effectorresponse An effector is any part of the body that produces the response. Here are some examples of effectors: a muscle contracting to move the arm a muscle squeezing saliva from the salivary gland hormonea gland releasing a hormone into the blood

14 GCSE Biology 1AHuman Biology NERVE FIBRES (neurones) (impulses)Nerve fibres are bundles of nerve cells (neurones) that pass on electrical signals (impulses) to the brain. effectorsFrom the brain, nerve fibres send impulses to effectors (muscles).

15 GCSE Biology 1AHuman BiologyNEURONES There are three types of neurones 1.Sensory neurone 1.Sensory neurone – carries impulses from the receptors to the spinal cord. 2.Relay Neurone 2.Relay Neurone – carries impulses to and from the spinal cord and the brain 3.Motor Neurone 3.Motor Neurone – carries impulses from the brain to the effector

16 GCSE Biology 1AHuman Biology Multiple-choice quiz

17 GCSE Biology 1AHuman BiologySYNAPSES neurones synapse Where two neurones meet, there is a tiny gap called a synapse. chemicals Signals cross this gap using chemicals. neurone One neurone releases the chemical into the gap. chemical neurone The chemical diffuses across the gap and makes the next neurone transmit an electrical signal. a/human/thenervoussystemrev2.shtml Watch this video on synapses then draw a flow chart of the process

18 GCSE Biology 1AHuman Biology What is a synapse? A synapse is a junction between two neurones across which electrical signals pass. The human body contains up to 500 trillion synapses. presynaptic cell postsynaptic cell

19 GCSE Biology 1AHuman Biology The release of neurotransmitters When a nerve impulse arrives at the end of one neurone it triggers the release of neurotransmitter molecules from synaptic vesicles. synaptic vesicle neurotransmitter molecules

20 GCSE Biology 1AHuman Biology Continuing the impulse The neurotransmitters diffuse across the synaptic cleft and bind with receptors on the next neurone, triggering another impulse. nerve impulse receptor synaptic cleft

21 GCSE Biology 1AHuman Biology The stick drop test! METHOD: 1.Working in pairs, one student holds a metre rule vertically at the zero end, between the thumb and forefinger of another student, so that the 50 cm mark is level with the top of the forefinger. 2.Without warning, the first student drops the rule and the second student attempts to catch it between the thumb and forefinger, noting the distance on the ruler just above the forefinger. 3.Repeat several times, so that a mean can be calculated. 4.Then change around so that everyone gets a turn. Write a report of the experiment. CONCLUSION AND DISCUSSION: What was the accuracy of the measurements, the calculation of means and the control of variables? Identify the parts of the body involved. What senses are being used? Can we train ourselves to react more quickly? Does practice make perfect? Can we alter reflex actions? – think of a situations where it is possible to alter the automatic response (not dropping a hot object, deliberately breathing more slowly, etc.). Are there some reflex actions over which we have no control?

22 GCSE Biology 1AHuman Biology REFLEX ARC reflex arcWhen your body needs to react to something very quickly (to protect itself) it uses a reflex arc (spinal reflex). Instead of sending impulses from the receptor Spinal cordbrainspinal cordeffector It sends impulses from the receptor spinal cordeffector…Yup it bypasses the brain! a/human/thenervoussystemrev3.shtml

23 GCSE Biology 1AHuman BiologyANSWERS Electrical impulses along neurones, chemical (neurotransmitters) across the synapse. The microscopic gap between two neurones. By chemicals called neurotransmitters. To pass the impulse onto the correct motor neurone. Glands or muscle that produce the effect or make a response.

24 GCSE Biology 1AHuman Biology The sequence of a reflex arc

25 GCSE Biology 1AHuman Biology REFLEX ACTION The way the iris in our eye adjusts the size of the pupil in response to bright or dim light is also a reflex action. a/human/thenervoussystemrev3.shtml In bright light In dim light Radial muscles of the iris relax. Circular muscles of the iris contract. Less light enters the eye through the contracted pupil. Radial muscles of the iris contract. Circular muscles of the iris relax. More light enters the eye through the dilated pupil.

26 GCSE Biology 1AHuman Biology The iris reflex

27 GCSE Biology 1AHuman Biology Inside the eye lens focuses light on retina iris regulates amount of light entering eye ciliary muscles change shape of the lens optic nerve transmits impulses to the brain cornea protects eye surface and focuses light rays retina senses light hold lens in place suspensory ligaments

28 GCSE Biology 1AHuman Biology REFLEX ACTION

29 GCSE Biology 1AHuman Biology PASS THE ZAP Some volunteers get an A4 sheets on which the names of parts of the reflex pathway are to be written. The students should then arrange themselves in the correct order. Using a lightning-shaped zap, each student is to talk through their bit of the process as the impulse (zap) gets passed to them.

30 GCSE Biology 1AHuman Biology NERVE PATHWAY… Have a go at completing this worksheet

31 GCSE Biology 1AHuman Biology NERVE PATHWAY… answers SENSORY NEURONE Takes impulses from the sense organ to the relay neurone. RELAY NEURONE Takes impulses to the brain and from the brain. MOTOR NEURONE Takes impulses from the relay neurone to the effector. BRAIN Receives impulses from the spinal cord and sends out new impulses. SENSE ORGAN/ RECEPTOR Senses stimuli from our surroundings. EFFECTOR The muscle that receives the impulse from motor neurone. SPINAL CORD Where the relay neurones are found.

32 GCSE Biology 1AHuman Biology NERVOUS SYSTEM… answers REFLEXPROTECTION GIVEN BLINKINGTo eye COUGHINGStops us choking SNEEZINGRemoves blockages from the nose PUPILS CHANGE SIZE Protects the retina 4a) 37m 55m/s = 0.67s 4b) RT = d s = 20m 40m/s = 0.5s 4c) sensory receptor in eye – sensory neurone – relay neurone - brain – motor neurone - effector 4d) i) brain, ii) takes too long iii) Stimulussensory neurone relay neuronemotor neurone effector

33 GCSE Biology 1AHuman Biology Glossary (1/2) accommodation – The reflex reaction that keeps the lens the right shape to focus light on the retina. CNS – The central nervous system, consisting of the brain and spinal cord. iris – The part of the eye that limits the amount of light entering the eye. lens – The part of the eye that focuses light on the retina. motor neurone – A neurone that carries electrical impulses from the CNS to muscles and glands. neurone – A specialized cell that carries electrical impulses.

34 GCSE Biology 1AHuman Biology Glossary (2/2) neurotransmitter – A chemical that diffuses across synapses to continue an impulse in a connecting neurone. reaction time – The time taken to respond to a stimulus. reflex – A fast, automatic protective response. retina – The part of the eye that contains light receptors. sensory neurone – A neurone that carries electrical impulses from sense organs to the CNS. synapse – The gap between two connecting neurones.

35 GCSE Biology 1AHuman Biology I AM LEARNING TO understand how the body is controlled I WILL LEARN THAT The nervous system enables humans to react to their surroundings and coordinate their behaviour. Receptors detect stimuli which include light, sound, changes in position, chemicals, touch, pressure, pain and temperature. Information from receptors passes along cells (neurones) in nerves to the brain. The brain coordinates the response. Many processes in the body are coordinated by chemical substances called hormones. Hormones are secreted by glands and are transported to their target organs by the bloodstream. I CAN Explain how the body control’s its functions and responses through hormones (chemicals) and nerves (electrical impulses) LEARNING OBJECTIVES


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