FORM 5 CHAPTER 3

1. FORM 5CHAPTER 3 COORDINATION AND RESPONSE

2. COORDINATION AND RESPONSE • An organism experiences changes in its internal and external environments all the time • The changes which cause responses in the body are called stimuli • There are two types of stimuli: a) internal b) external 4. Mammals detect stimuli through highly specialised sensory cell called receptor. 5. Effectors in the body carry out the responses to stimuli

3. COORDINATION AND RESPONSE • When the stimuli are detected and eventually resort in an appropriate response, it is called coordination • The roles of coordination and response are carried out by two different coordinating systems, namely the nervous system and the endocrine system

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5. The main component and pathway involved in detecting and responding to changes in the external environment puteri5578

6. The main component and pathway involved in detecting and responding to changes in the internal environment puteri5578

7. THE ROLE OF HUMAN NERVOUS SYSTEM • Organisation of the nervous system • The human nervous system consist of a giant network of nerve cells or neurones, and nerve tissues which convey information between the sensory receptors, the organs and effectors. • It is divided into main subsystem: a) central nervous system (CNS), consist of brain and spinal cord b) peripheral nervous system (PNS), consist of cranial nerves and spinal nerves. puteri5578

8. Human nervous system puteri5578

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10. Cerebrum • Divided into two halves called the cerebral hemispheres (left and right) • It is responsible for many mental abilities Cerebellum • Coordinating centre for body movements • Evaluates the information and relays the need for coordinated movements back to the cerebrum • Then sends appropriate commands to the muscle puteri5578

11. Medulla oblongata • Regulates the internal body processes that do not requires conscious effort, that is, automatic functions such as the heart beat and breathing. • Reflex centre for vomiting, coughing, sneezing, hiccupping and swallowing. Hypothalamus • Important role in homeostatic regulation. • Control centre of the endocrine system puteri5578

12. Pituitary gland • Secretes hormones that influence other glands and body function • Controls the release of several hormones from the pituitary gland and thereby serve as important link between the nervous and endocrine system. Thalamus • Responsible for sorting the incoming and outgoing information in the cerebral cortex • Integrates the information from the sensory receptor to the cerebrum by enhancing certain signals blocking others. puteri5578

13. The spinal cord and its function • Contain within the vertebral column • It is consist of white matter and grey matter a) in cross section, grey matter looks like a butterfly or the letter H b) consist mainly of cell bodies of neurones c) surrounded by white matter d) the white matter comprises myelin-coated axons of neurones that extend the whole length of the spinal cord puteri5578

14. A cross section of the spinal cord showing the white matter and the grey matter puteri5578

15. The neurones • The nervous system is made up of millions of nerve cells called neurones • Neurones transmit nerve impulses to other nerve cells, glands or muscles puteri5578

16. Types of neurones • Neurones afferent (sensory) • Carry sensory information from receptor cell to the brain and spinal cord. puteri5578

17. Types of neurones • Neurones efferent • carry information from the brain or spinal cord to the effectors, that is the muscle or gland cells puteri5578

18. Types of neurones • Interneurones • convey nerve impulses between the various parts of the brain and spinal cord, transmit nerve impulses between afferent and efferent puteri5578

19. The transmission of information across synapses • Synapse is the site where two neurons, or a neuron and a effector cell communicate. • The transmission of information across a synapse involve the conversion of electrical signals in the form of neurotransmitter • The function of synapses include controlling and integrating the nerve impulses transmitted by the stimulated receptors puteri5578

20. Voluntary action and involuntary action • The PNS has two main function • It transmits signal to the CNS for processing • It transmits responses from the CNS to the rest of the body • Voluntary actions such as walking and talking are under conscious control • Involuntary actions that involve skeletal muscle allows immediate action that does not require conscious effort puteri5578

21. For example, if a finger touch a hot stove, the reaction is to pull the finger immediately without having to think about it • In such circumstance when the responses to stimuli are involuntary, they are called reflexes. • The nerve pathway involved in a reflex action is called a reflex arc • The effectors involved in involuntary action are smooth muscle and cardiac muscle puteri5578

22. Diseases of the nervous system Parkinson’s disease • Is a progressive disorder of a CNS that typically affect victims around the age of 60 years onwards. • Parkinson’s disease affect muscular movements, causing tremors or trembling of the arms, jaws legs and face • Patients also have difficulty in maintaining normal postures and experience impaired balance and coordination puteri5578

23. Alzheimer's disease • Alzheimer's disease is a neurological disorder which affect victims around the age of 60yearsonwards, causes the loss of reasoning and the ability to care for oneself. • Individual of Alzheimer's disease often become confuse, forgetful, and lose their way although they are in place which are familiar to them. • As their mind continue to deteriorate, patients may lose the ability to read, write, eat, walk and talk. • the cause of this disease still unknown, but the factors such as genetic, environmental or the aging process itself can lead to Alzheimer's disease puteri5578

24. The role of hormone in human • Endocrine system consists of a number of glands that secrete hormones. • Hormones are the chemical messenger produce by the endocrine glands. • Although the hormones travel in the blood of the body, they affect and influence only the specific target cell. • Once the hormone binds to its target cell, the hormone cause the cell to respond in the specific manner. puteri5578

25. The transport of hormones to target cells puteri5578

26. The need for the endocrine system • The endocrine system and nervous system play important roles in maintaining homeostasis. • Both this system often works together. puteri5578

27. The nervous system • Control voluntary and involuntary actions • Conveys electrical signals • Messages are conducted via neurones. • Messages are conveyed rapidly • Messages are carried between specific locations • The responses or effect are temporary The endocrine system • controls involuntary actions • Conveys chemical signal (hormones) • Messages are conveyed via the bloodstream • Message are conveyed slowly • Messages are carried from the source to the various destination • The response or effects are long-lasting puteri5578

28. Regulation of hormones secretion • The pituitary gland is regarded as the master endocrine gland because it secrete several hormones that control other endocrine gland • Pituitary gland itself controlled by the hypothalamus. • Pituitary gland consist of two parts: a) posterior pituitary b) anterior pituitary • The posterior pituitary contains the axons and synaptic terminals of the neurosecretory cells that originate in the hypothalamus puteri5578

29. ACTH TSH FSH & LH Growth hormones prolactin The role of the hypothalamus in regulating the secretion of hormones from the pituitary gland Hypothalamus Anterior pituitary Anterior pituitary oxytocin ADH Kidney tubules Smooth muscle in the uterus Adrenal cortex Thyroid Ovaries, testes Bones, tissues Mammary glands puteri5578

30. ADH and axytocin are synthesised in the neurosecretory cells of the hypothalamus but secrete by the posterior pituitary • The hypothalamus controls the hormone secretion of the anterior pituitary gland and therefore, affect the secretion of many other endocrine glands indirectly. • The anterior pituitary controls the secretions of hormones from the thyroid gland, the adrenal gland and gonad. All of which are also endocrine glands.

31. Negative feedback mechanism in hormone regulation HYPOTHALAMUS Thyroid-releasing Hormone, TRH Stimulates the anterior pituitary to secrete TSH Negative feedback inhibits the release of TRH ANTERIOR PITUITARY Thyroid-stimulating Hormone, TSH Negative feedback inhibits the release of TSH Stimulates the target gland to secrete Thyroxine TARGET GLAND Thyroxine When the thyroxine concentration exceeds a certain level in the blood, its inhibits TRH production in the hypothalamus and TSH production from the anterior pituitary puteri5578

32. HOMEOSTASIS IN HUMAN • Homeostasis is the maintenance of a relatively constant internal environment. • Physical factor such as body temperature and blood pressure while chemical factor are sugar level and osmotic pressure such as partial of carbon dioxide and oxygen The excretory system • Plays an important role in homeostasis • The primary organs of the excretory system are the kidneys. puteri5578

33. Function of the kidneys • Helps to regulates the water and salt balance in the body by excreting more or less salt, and increasing the in take or loss of water. • Regulate the osmotic pressure and ionic levels in the blood • Excrete waste products. • Regulate the blood pH • Waste products excreted by the kidneys are substances that are not useful to the body such as waste products from the metabolic reaction (urea, creatinine and uric acid) and foreign substances in the diet (drugs or toxins) puteri5578

34. The human kidney • The kidneys filter the blood and form the urine which is exits the body through the ureters, urinary bladder and urethra. • Urine consists of water, urea and other dissolved waste, and some excess nutrients. • Human kidney has two distinct region: • Renal cortex • Renal medulla puteri5578

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36. The nephron • The functional unit of the kidney is the nephron. • The human kidney consists of about 1 million nephrons. • A nephron consists of three major parts: • Glomerulus • Bowman’s capsule • Renal tubule • Renal tubule is made up of the: • Proximal convoluted tubule • Loop of Henle • Distal convoluted tubule puteri5578

37. Nephron puteri5578

38. Nephron perform three basic process: • Ultrafiltration • Reabsorption • Secretion Ultrafiltration • When the blood enters the glomerulus, ultrafiltration take place when the high pressure forces fluid through the filtration membrane into the capsular space • The fluid that enters into the capsular space is called the glomerular filtrate • glomerular filtrate contain water, glucose, amino acid, urea, mineral salt and other small molecule. Some composition as blood plasma but not contain red blood cells and plasma protein puteri5578

39. Ultrafiltration in bowman’s capsule puteri5578

40. Reabsorption • Reabsorption take place when the substance moves across the renal tubule into the capillary network. • In the proximal convoluted tubule, there are abundance of mitochondria to generate ATP for the process of active transport that used to reabsorb glucose and amino acid. • Solute concentration in the capillary network is increase, so that water moves into the blood capillary by osmosis • In the loop of Henle, water, sodium and chloride ions are reabsorbed. puteri5578

41. At the distal convoluted tubule, more water, sodium and chloride ions are reabsorbed. • B the time, the filtrate reaches the collecting duct, very little salt left and 99% of water has been reabsorbed into the bloodstream. • Only 1% of water in the filtrate actually leaves the body as urine. • Some urea diffuses out into the surrounding fluid and blood because of its small molecular size. • Finally, about 45% of the original urea remain in the collecting duct to be excrete in the urine. puteri5578

42. Secretion • Not everything is filtered, only 20% of the plasma leaves the blood vessels and enters the renal tubule. Hence there are waste product in the blood which were not filtered originally. • Secretion is a process in which waste and excess substances that were not initially filtered are secreted into the renal tubule. • Secretion take place in the renal tubules and collecting ducts but is especially active at the distal convoluted tubule. • Secretion occurs by passive diffusion and active transport. puteri5578

43. Detected by osmoreseptors in hypothalamus An increased in ADH released from posterior pituitary Increased permeability of distal convoluted tubule and collecting duct to water Decrease in solute potential Greater proportion of water reabsorption in renal tubules Decreased water intake A small volume of concentration urine produced Plasma solute potential increases Normal plasma osmotic level A large volume of dilute urine produced Plasma solute potential decreases Increased water intake Increased in solute potential smaller proportion of water reabsorption in renal tubules A decreased in ADH released from posterior pituitary Detected by osmoreseptors in hypothalamus Decreased permeability of distal convoluted tubule and collecting duct to water REGULATION OF ADH PRODUCTION

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45. Notes about Kidney Dialysis: • The main stages that blood passes through during the dialysis process include: • Blood enters machine from body (under pressure from radial artery). • Pump (some diagrams show a roller pump) controls pressure and flow rate. • Anticoagulant added to prevent clotting. • Blood passes through dialysis membrane (equivalent to kidney nephrons). • Bubble Trap removes any gas bubbles from blood. • Blood is filtered then returned to the patient's radial vein. puteri5578

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47. After meal During fasting or after exercise Rise in blood glucose level Drop in blood glucose level Secretion of more insulin or less glucagon by pancreas Secretion of less insulin or more glucagon by pancreas Liver cells absorb glucose from blood to form glycogen Liver cell break down glycogen into glucose Decrease in glucose uptake by body cells for respiration Increase in glucose uptake by body cells for respiration + + Blood glucose level returns to normal BLOOD GLUCOSE LEVEL IN THE BODY

48. Practising a healthy lifestyle • Drugs can alter brain functions and the rates at which neurones release neurotransmitters • There are some types of drug and their effects on the body: puteri5578

49. Stimulants • Increase the activity of the central nervous system • Cocaine, nicotine, amphetamines & caffeine increase the heart rate and alertness • Hallucinations, LSD perceive things that do not exist puteri5578

50. Depressants • Slow down the activity of the central nervous system • Alcohol, barbiturates & heroin slow down the breathing rate &lower blood pressure puteri5578