16 Coordination in humans

1. 16 Coordination in humans

2. Think about it 16.1 What does our nervous system consist of ? 16.2How does the nervous system function? 16.3What is the structure of the spinal cord and what are its functions? 16.4What is a reflex action? 16.5What is the structure of the brain and what are its functions? 16.6What are the differences between reflex actions and voluntary actions?

3. 16.7What is hormonal coordination? 16.8How does hormonal control work? 16.9What are the similarities and differences between hormonal and nervous coordination? Practical 16.1 STS connection 16.1STS connection 16.2 Summary concept diagram

4. Sanglan (桑蘭), a famous Chinese gymnast became paralysed (癱瘓) below her thorax after an accident in a practice vault (跳馬) .

5. What changes occurred in her body after the accident?

6. Which part of her body was damaged?

7. Do you know the causes of paralysis in other people who have this disability?

8. Our nervous system is important in coordinating the receptors and effectors in our body. Damage in any part of the nervous system may cause paralysis. Do you know the causes of paralysis in other people who have this disability?

9. 16.1 What does our nervous system consist of ? nervous system endocrine system coordination in mammals

10. 16.1 What does our nervous system consist of ? Nervous system • coordinates the receptors and effectors • consists of two parts: 1central nervous system (CNS) 2peripheral nervous system (PNS)

11. General plan of the nervous system peripheral nervous system (PNS) central nervous system (CNS) cranial nerve brain spinal cord spinal nerve

12. Protection of the central nervous system Brain cranium 3 layers of membranes central cavity filled withcerebrospinal fluid (腦脊髓液) • provides brain with nutrients and oxygen • removes wastes from brain cells • absorbs shock • maintains shape of brain

13. Protection of the central nervous system Spinal cord spinal cord central canal filled with cerebrospinal fluid 3 layers of membranes vertebral column

14. 16.2 How does the nervous system function? Nervous system is made up of neurones (神經元). Neurones … nerve cells basic units of the nervous system transmit nerve impulses

15. Structure of the neurone cytoplasm nerve fibre nucleus dendron (樹突) axon (軸突) myelin sheath (髓鞘) cell body

16. Structure of the neurone a nerve fibre (axon or dendron) • Nerves • nerve fibres of many neurones wrapped in connective tissue a bundle of nerve fibres connective tissue The make-up of a nerve

17. Types of neurones in CNS 1 Sensory neurone axon impulses cell body receptors CNS dendron receptor

18. Types of neurones in CNS 2 Motor neurone cell body impulses effector CNS axon effector

19. Types of neurones 3 Interneurone cell body sensory neurone motor neurone impulses in CNS dendron axon

20. Transmission of nerve impulses between neurones • neurones are separated by synapses (突觸) • synapses cause nerve impulses to travel in one direction only

21. Transmission of nerve impulses between neurones axon chemicals released from axon ending diffuse across a synapse synapse dendron

22. CNS PNS The role of nervous system stimuli 1receptor e.g. pain receptor receives stimuli and generates nerve impulses receptors sensory neurone 2 impulses are transmitted to the CNS via sensory neurones interneurone interneurone from brain motor neurone effector

23. CNS PNS The role of nervous system brain spinal cord receptors sensory neurone 3 information is processed (處理) and integrated (融合) in CNS which then generates nerve impulses interneurone interneurone from brain motor neurone effector

24. CNS PNS The role of nervous system 4 impulses are transmitted via motor neurones to the effector, e.g. muscle receptors sensory neurone interneurone 5 effector brings about a response, e.g. muscle contraction interneurone from brain motor neurone effector response

25. Brief Revision ~ Word corner ~ Cranium, Neurone ** Crani-  Skull ** Neuro- Nerve

26. 16.3 What is the structure of the spinal cord and what are its functions? Structure of the spinal cord white matter (outer layer) grey matter (inner layer) dorsal root (sensory neurones) ventral root (motor neurones) dorsal root ganglion (cell bodies of sensory neurones) spinal nerve

27. Functions of the spinal cord • relays nerve impulses between the brain and other body parts • responsible for many reflex actions brain nerve impulses enter and leave the brain through the spinal cord spinal cord

28. 16.4 What is a reflex action? • inborn • rapid • involuntary • stereotyped (有固定形式的) reflex action (反射動作) is can be cranial reflex spinal reflex brought about by brought about by • impulses travelling through brain • impulses travelling through spinal cord

29. Reflex arc • the nervous pathway between a receptor and an effector which brings about a reflex action 2 sensory neurone 1 receptor 3 intermediate neurone (may be absent) 4 motor neurone 5 effector

30. Examples of reflex actions Withdrawal reflex 4 interneurone 6 arm muscle (effector) contracts 5 motor neurone 7 hand withdraws 1stimulus 3 impulses sent through sensory neurone 2 pain receptors are stimulated

31. Examples of reflex actions Knee jerk reflex 3 impulses sent through sensory neurone 2 stretch receptor is stimulated 1 tendon below the knee cap is tapped 4 motor neurone 5 leg muscle (effector) contracts 6 the leg kicks

32. 16.5 What is the structure of the brain and what are its functions? 3 main parts: cerebrum (大腦) cerebellum (小腦) medulla (延腦)

33. 1 Cerebrum • site of intelligence and controls voluntary actions Outer layer: cerebral cortex grey matter (cell bodies) Inner layer: white matter (axons and dendrons)

34. 1 Cerebrum • consists of 2 halves: 1) left cerebral hemisphere • controls right side body movement 2) right cerebral hemisphere • controls left side body movement • the 2 halves are connected by nerves for communication

35. 1 Cerebrum 3 main areas in the cerebral cortex: • Sensory areas • receive impulses from various receptors • Association areas • link information from different sensory areas/receptors • Motor areas • send out impulses to effectors

36. 2 Cerebellum • outer layer: grey matter inner layer: white matter • coordinates muscular movements • maintains balance cerebellum

37. 3 Medulla • controls many reflex actions and involuntary actions • outer layer: white matter • inner layer: grey matter reverse of that in cerebrum and cerebellum medulla

38. 16.1 Examination of a human brain model Procedure: 1 Examine a human brain model. 2 Identify the structures. 3 Notice the folds on the surface of the brain.

39. 16.1 Effects of drug abuse on body organs  Conduct a project on the effects of drug abuse on body organs, particularly the brain. Go to Activity Book 2, p.143

40. Brief Revision 1 Of the three main parts of the brain, _________ controls voluntary actions, whereas ___________ and _________ controls involuntary actions. cerebrum cerebellum medulla 2 The three main areas in the cerebral cortex are the ________ area, the __________ area and the _______ area. sensory motor association

41. Reflex actions Voluntary actions 16.6 What are the differences between reflex actions and voluntary actions? involve cerebrum? Yes No under conscious control? Yes No involve receptor? Not necessarily Yes

42. Reflex actions Voluntary actions 16.6 What are the differences between reflex actions and voluntary actions? No, they are learnt Yes inborn? speed of response Slower Faster Various responses Stereotyped response response to same stimulus

43. Extension 16.7 What is hormonal coordination? pituitary gland (腦下垂體) Endocrine system thyroid gland (甲狀腺) • responsible for coordination by hormones • consists of many endocrine glands (內分泌腺) pancreas adrenal glands (腎上腺) ovaries (卵巢) testes (睾丸) woman man Main endocrine glands

44. Extension 16.7 What is hormonal coordination? Hormones • chemicals secreted by ductless endocrine glands transported in blood • serve as chemical messengers which act on target organs and regulate body processes

45. Extension Transport of hormones: 2 hormones diffuse into blood 4 cells in specifictarget organsreceive hormones and changes occur 1 secreting cells in endocrine gland secretehormones 3 hormones are transported to all parts of the body

46. Extension Examples of endocrine glands Ovaries and testes • produce sex hormones (性激素) which 1 stimulate ovaries to release eggs (卵子) and testes to make sperm (精子) 2 responsible for the development of secondary sexual characteristics(第二性徵)

47. Extension Examples of endocrine glands Pancreas • produce insulin (胰島素) and glucagon (高血糖素) • they work together to regulate the blood glucose level insulin glucose glycogen glucagon

48. Extension 16.8 How does hormonal control work?  by a negative feedback mechanism (負反饋機制) balancing action to decrease the level higher level of factors than normal detector normal level of factors negative feedback balancing action to increase the level lower level of factors than normal detector

49. The operation of a thermostat (恆溫器) of an air-conditioner Extension An everyday example: RT = room temperature S = set temperature

50. Extension Regulation of blood glucose level More insulin is secreted (1) more glucose is converted to glycogen in liver (2) more glucose is oxidized to CO2 and H2O in body cells High blood glucose level Blood glucose level falls Normal blood glucose level Low blood glucose level Less insulin is secreted (1) more glycogen in liver is converted to glucose (2) less glucose is oxidized in body cells Blood glucose level rises