form 5 note_chapter_3
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A powerpoint slide to explain the concepts of Coordination and Response, Biology Form 5, Chapter 3TRANSCRIPT
FORM 5CHAPTER 3
COORDINATION AND
RESPONSE
Kirsten (ThinkTankCentre)
COORDINATION AND RESPONSE
1. An organism experiences changes in its internal and external environments all the time
2. The changes which cause responses in the body are called stimuli
3. There are two types of stimuli:a) internalb) external
4. Mammals detect stimuli through highly specialised sensory cell called receptor.
5. Effectors in the body carry out the responses to stimuli
Kirsten (ThinkTankCentre)
COORDINATION AND RESPONSE
5. When the stimuli are detected and eventually resort in an appropriate response, it is called coordination
6. The roles of coordination and response are carried out by two different coordinating systems, namely the nervous system and the endocrine system
Kirsten (ThinkTankCentre)
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The main component and pathway involved in detecting and responding to changes in the external environmentputeri5578 5
The main component and pathway involved in detecting and responding to changes in the internal environmentputeri5578 6
THE ROLE OF HUMAN NERVOUS SYSTEM
• Organisation of the nervous system1. 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.
2. It is divided into main subsystem:a) central nervous system (CNS), consist of brain and spinal cordb) peripheral nervous system (PNS), consist of cranial nerves and spinal nerves.
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Human nervous systemputeri5578 8
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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
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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.
• Important role in homeostatic regulation.• Control centre of the endocrine system
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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.
Hypothalamus• 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.
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The spinal cord and its function
1. Contain within the vertebral column2. It is consist of white matter and grey matter
a) in cross section, grey matter looks like a butterfly or the letter Hb) consist mainly of cell bodies of neuronesc) surrounded by white matterd) the white matter comprises myelin-coated axons of neurones that extend the whole length of the spinal cord
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A cross section of the spinal cord showing the white matter and the grey matterputeri5578 14
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
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Types of neurones
Neurones afferent (sensory)
• Carry sensory information from receptor cell to the brain and spinal cord.
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Types of neuronesNeurones
efferent• carry
information from the brain or spinal cord to the effectors, that is the muscle or gland cells
Kirsten (ThinkTankCentre) 17
Types of neurones Interneurones• convey nerve
impulses between the various parts of the brain and spinal cord, transmit nerve impulses between afferent and efferent
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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
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Voluntary action and involuntary action
• The PNS has two main function1. It transmits signal to the CNS for processing2. 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
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• 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
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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
22Kirsten (ThinkTankCentre)
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
23Kirsten (ThinkTankCentre)
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.
24Kirsten (ThinkTankCentre)
puteri5578 25The transport of hormones to target cells
The need for the endocrine system
1. The endocrine system and nervous system play important roles in maintaining homeostasis.
2. Both this system often works together.
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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
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
Kirsten (ThinkTankCentre)
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 pituitaryb) anterior pituitary
• The posterior pituitary contains the axons and synaptic terminals of the neurosecretory cells that originate in the hypothalamus 28Kirsten (ThinkTankCentre)
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The role of the hypothalamus in regulating the secretion of
hormones from the pituitary gland
Hypothalamus
Anterior pituitary
Anterior pituitary
ADH oxytocin
ACTH TSH FSH & LHGrowth hormonesprolactin
Kidney tubules
Smooth muscle in the uterus
Adrenal cortex
Thyroid Ovaries, testes
Bones, tissues
Mammary glands
• 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.
Kirsten (ThinkTankCentre)
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HYPOTHALAMUS Thyroid-releasing
Hormone, TRH
ANTERIOR PITUITARYThyroid-stimulating
Hormone, TSH
TARGET GLANDThyroxine
Stimulates the anterior pituitary to secrete TSH
Stimulates the target gland to secrete 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
Negative feedback inhibits
the release of TSH
Negative feedback inhibits
the release of
TRH
Negative feedback mechanism in hormone regulation
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.
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Function of the kidneys1. 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.
2. Regulate the osmotic pressure and ionic levels in the blood
3. Excrete waste products.4. 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)
33Kirsten (ThinkTankCentre)
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:a) Renal cortexb) Renal medulla
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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:a) Glomerulusb) Bowman’s capsulec) Renal tubule• Renal tubule is made up of the:a) Proximal convoluted tubuleb) Loop of Henlec) Distal convoluted tubule
36Kirsten (ThinkTankCentre)
puteri5578 37Nephron
• Nephron perform three basic process:1. Ultrafiltration2. Reabsorption3. 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
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Ultrafiltration in bowman’s capsule
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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.
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• 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.
41Kirsten (ThinkTankCentre)
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.
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Detected by osmoreseptors in hypothalamus
Decrease in solute potential
Normal plasma osmotic level
Increased in solute potential
Detected by osmoreseptors in hypothalamus
Increased permeability of distal convoluted tubule and collecting duct to waterGreater proportion of water reabsorption in renal tubules
A small volume of concentration urine produced
A large volume of dilute urine produced
smaller proportion of water reabsorption in renal tubules
Decreased permeability of distal convoluted tubule and collecting duct to water
An increased in ADH released from posterior pituitary
A decreased in ADH released from posterior pituitary
Plasma solute potential decreases
Plasma solute potential increases
Increased water intake
Decreased water intake
REGULATION OF ADH PRODUCTION
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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.
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BLOOD GLUCOSE LEVEL IN THE BODY
After meal
Rise in blood glucose level
Secretion of more insulin or less
glucagon by pancreas
Liver cells absorb glucose
from blood to form
glycogen
Increase in glucose
uptake by body cells for
respiration
Liver cell break down
glycogen into
glucose
Decrease in glucose
uptake by body cells for respiration
Drop in blood glucose level
Secretion of less insulin or more
glucagon by pancreas
During fasting or after exercise
Blood glucose level returns to normal
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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:
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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
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Kirsten (ThinkTankCentre)
Depressants• Slow down the activity of the central nervous
system• Alcohol, barbiturates & heroin slow down the
breathing rate &lower blood pressure
50Kirsten (ThinkTankCentre)
Plants hormones• Plants hormones is a chemical substances which
is produced by the plants and influences the growth and development of the plants. Examples auxins and ethylene
Auxins• Auxins controlled the plants respond to stimuli by
growing in a certain direction called tropism.• Growth of shoots towards sunlight is called +ve
phototropism and growth of shoots away from sunlight is called -ve phototropism.
• Auxins promotes the elongation of cells in the shoot
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• The growth movement of a plant is response to gravity is called geotropism.
• Auxins is used to:a) Increase the stem length by increasing the rate of cell
divisionb) Stimulate the growth of adventitious roots from the
stemc) Parthenocarpy, produce seedless fruitd) Promotes growth of plants cells. Delay fruit ripening
and prevent fruit from falling off the plant before it is ripe
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Ethylene• Ethylene is a plant hormones which is synthesised
during the ripening of fruits.• The synthesis of ethylene occurs in fruits, leaves and
stems• Speedup the ripening of fruits by stimulating the
production of cellulase that used to hydrolyses the cellulose in plants cells walls, making the fruits soft.
• Promotes the breakdown of complex carbohydrates into simple sugar. That is why a ripe fruit tastes sweeter than an unripe fruit
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THE END
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