55054737 c12
TRANSCRIPT
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COORDINATION AND RESPONSE
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• Living organisms have the ability to detect the internal and external environment changes
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The changes which cause response in the body are called stimuli
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• Two types of stimuli:
• (a) internal stimuli• Changes in blood pressure, sugar level
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• (b) external stimuli– Changes in light intensity, sound, temperature,
pressure, touch
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Stimuli receptors Effector
Response
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• A response is the ways an organisms react after stimulus is detected
Stimuli receptors Effector
Response
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When stimuli are detected and eventually result in reponse it is called coordination
Stimuli receptors Effector
Response
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• Coordination ensures the activities of an organism function as an intergrated whole
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Coordination and response
Nervous system Endocrine system
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Nervous system
Sensory receptors
Intergrating centre
effectors
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PeripheralNervous system
efector
Central nervoussystem
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• Sensory receptors – Detect changes in the external environment
• Found in eyes, nose, ears, tongue, skin
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- Detect changes in the internal environment
Located in specific internal organs
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• Examples of external environment receptors:– Light sensitive cell in the retina
– Temperature and touch receptor in the skin
– Vibration sensitive cells in the ears
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• Examples of internal environment receptors :–Cells sensitive to level of carbon dioxide in the
blood, blood osmotic pressure
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Pancreatic cells detect blood glucose level
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• Intergrating centre– Intergrating centre is the central nervous system
( brain, spinal cord)
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Intergration happens when information from the receptors is interpreted to bring appropriate response
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• Effectors – Carry out the responses to stimuli
– Effectors – muscle cells, glands
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Sensory receptor is stimulated , nerve impules are generated
Impulse carried along the afferent pathway throughthe afferent nerves
Impulses arrive at the intergrating centre
Integration centre sent response in the impulse form
Impulses is carried by efferent pathway through the efferent nerves to effectors
Reponse to the stimuli take place
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Pathway involved in detecting and responding to change in the internal environment
Change in the blood temperature
Detected by temperaturesensitive cells in hypothalamus
Impulses are carried by afferent nerves to the thermoregulatory centre in hypothalamus
Integration occur in thermoregulatory centre
Impulses are carried from hypthalamus to the effector throughefferent nerves
Effectors – smoothmucles of the arterioles,sweat gland, etc
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Change in the blood temperature
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Detected by temperature
sensitive cells in hypothalamus
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Impulses are carried by afferent nerves to the thermoregulatory centre in hypothalamus
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The role of the human nervous system
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Human nervous system
Central nervous system
Peripheral nervous system
brain Spinal cord Cranial nerves
spinal nerves
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Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves which emerge from segments of the spinal cord
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• Nervous system performs three main functions :– 1. sensory
– 2. intergrative
– 3. motor
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• sensory receptors detect stimuli – initiate impulses that carry information to the CNS
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• CNS – initiate suitable responses
• Motor commands from the CNS are transmitted to the effectors - muscles, glands
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• Human brain :– Cerebrum
– Cerebellum
– Medulla oblongata
– Thalamus
– Hypothalamus
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Cerebral cortex
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Cerebrum
- largest, most complex part of the brain
- divided into two – left hemisphere - right hemisphere
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• Left hemisphere – controls movements on the right side of the body
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Functions – receive the sensory input and carries out integrative functions before initiating motor response
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– Coordinates the activities other parts of the brain
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• Outer region of the cerebrum - cerebral cortex– Many folds to increase surface area
Cerebral cortex
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– Function –• directs voluntary muscle movement, result in sensory
perception (know what he sees, hears, smell)
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Mental abilities – learning, memorising, reasoning, language skills, mathematic skills, imagination, artistic talents, personality
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• Damage to this area can cause specific defect – speech impairment, reading difficulty, paralyse
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• Cerebellum– The coordinating centre for body movements
– Receieves information from sensory receptor from all parts of the body and from the cerebrum
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– Evaluate infromation and relays the need for coordinated movements back to the cerebrum
– Cerebrum then sends appropriate commands to the muscles
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• Medulla oblongata– Function –
• regulates the internal body processes that do not require conscious effort – heartbeat, breathing, vasoconstriction
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• Reflex centre for vomiting, coughing, sneezing, hiccupping, swallowing
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• Hypothalamus– Function – homeostatic regulation
– Coordintion centre for regulating sleep, hunger, thirst, body temperature, water balance, blood presure
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– Control centre for endocrine system (hormone)
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• Pituitary gland– Function – secretes hormones that influence other
glands and body functions
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The hypothalamus controls the release of several hormone from the pituitary gland
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• Thalamus – Function –
• sorting the incoming and outgoing information in the cerebral cortex
• Enhancing and blocking signals from the sensory receptors to the cerebrum
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The spinal cords and it functions• Spinal cord is surrounded by cerebrospinal fluid
-shock absorber and provide nutrients
• Consist of white matter and grey matter
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Dorsal rootganglion
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• Spinal nerves emerge from the spinal cord through two branches/ roots:
• Dorsal roots
• Ventral rootsDorsal root
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• Dorsal roots – Contains axon of the afferent neurons which conduct
nerve impulses from the sensory receptors to the spinal cord
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Dorsal rootganglion
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– Dorsal root ganglion contains the cell bodies of afferent neurons
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• Ventral root– Contains the axons of the efferent neurons which
conduct impulses away from the spinal cord to the effector
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Dorsal rootganglion
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• The spinal cord :– Processes sensory information and send out
responses through the efferent neurones
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– Contains neurones that transfer signals to and from the brain
– Neural pathway for reflexes
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receptor Neuron afferent Spinal cord
brain
Neuron efferent
Effectors /muscle
Pathway off the impulse
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The neurones
• The nervous system is made up of millions of nerve cells calls neurones
• Neurones transmit nerve impulses to other nerve cells, glands, muscles
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• Three types of neurones:• Afferent neurones
• Efferent neurones
• internuerones
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• Afferent neurones – Carry sensory information from the receptor cells to
the brain and spinal cord
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Movement of impulse
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• Efferent neurones – Carry information from the brain or spinal cord to the
effectors (muscle, gland cells)
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Movement of impulse
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• Interneurones– Convey nerve impulses between various parts
of the brain and spinal cord– Transmit nerve impulses between afferent
neurones and efferent neurones– Transmit nerve impulses from one side of the
spinal cord to the other side or from brain to the spinal cord
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The transmission pathway of information
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Receptors pick up the ringing of doorbell
Nerve impulses from the receptors moves in the afferent neruones
Nerve impulses transfer from the afferent to theinterneurons
Interneurones sent impulses to the brain
Brain interpretes impulses, give order in the form of impulses
From the interneurones impulses is transmitted tothe efferent neurones and thento the muscles
The muscles in the arm carry out response
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The transmission of information along the neurones
• The transmission of information along the neurones is through electical signals known as nerve impulses
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• Impulse – positive charges that travel along the axon to the synaptic terminal
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• A neurones will not transmit impulses if the stimulation is not strong enough
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Afferent neurones interneurones Efferent neuronesimpulse impulse
Receptor
Brain
impulse
Stimulus
impulse
Interpret, Integration,Response
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Receptors pick up the ringing of doorbell
Nerve impulses from the receptors moves in the afferent neruones
Nerve impulses transfer from the afferent to theinterneurons
Interneurones sent impulses to the brain
Brain interpretes impulses, give order in the form of impulses
From the interneurones impulses is transmitted tothe efferent neurones and thento the muscles
The muscles in the arm carry out response
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The transmission of information across synapses
• Neurones are not connected to each other
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• Beyond the synaptic terminal there is synaptic cleft (narrow space) that separate synaptic terminal from the dendrite of a receiving neurones
Synaptic cleft
Synaptic terminal
dendrite
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• Synapse is the site where two neurones or a neurone and an effector cell communicate
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• Electrical signals must be transmitted across the synaptic cleft to an adjacent cell
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• The transmission of nerve impulses across the synaptic cleft occurs with the help of neurotransmitter (chemical substances)
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• Neurotransmitter is stored in the synaptic vesicles
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• The transmission of impulses involves the conversion of electrical signal into chemical signals
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Electrical signal
Chemical signal
Electrical signal
(neurotransmitter)
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Electrical impulses reaches the presynaptic membrane
Neurotransmitter diffuseacross the synaptic cleftand bind to specific protein/receptorsthat attached to the postsynaptic membrane
Binding of the neurotransmitter to receptorsgenerates a new impulses signal
Impulses is transferred to another neurones
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• The transmission of nerve impulses across synapses is an active process which required energy
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• Synaptic terminal contains abundant mitochondria to generate energy for transmission of nerve impulses
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• After the neurotransmitter has relayed its message – Broken down by enzymes
– Taken up again by the synaptic terminal and recycled
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• Examples of neurotransmitter :• Acetylcholine
• Noradrenaline
• Serotonin
• dopamine
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• The functions of synapses :• Controlling and intergrating the nerve impulses
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• Facilitating the transmission of nerve impulses in one direction
– Synaptic vesicles only present in synaptic terminals
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– Only presynaptic membrane can discharge neurotransmitter
– Receptors only present in postsynaptic membranes
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Action of skeletal muscle
Voluntary action Involuntary action
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• Voluntary action of the skeleton muscle– Voluntary actions are under conscious control
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– Information that reaches cerebral cortex or conscious level result in a perception of the external environment
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Stimulus receptor Afferent neurone
Cerebral cortex
Efferent neurone
effector
response
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• Involuntary action that involves the skeletal muscles: the reflex arc– Involves skeletal muscle that does not require
consciuos effort
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• Example – if a finger touch a hot stove, the reactions is to pull the finger away without having to thing
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• Rapid, automatic
• The nerve pathway involved is called reflex arc
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Reflex arc
Sharp pin pierces the skin – sensory receptorin the skin generate nerve impulses
Nerve impulses transmitted along an afferent neurone toward the spinal cord
In spinal cord the nerve impulses are transmitted to the interneurone
From interneurone the impulses are transmitted to the efferent neurone
Efferent neurone carries the nerve impulses to the effector
Pin can be pulled out immediately
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The importance of reflexes
- Cut the time of response
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- the pain is slightly delayed after the response has been made
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• Only involves the spinal cord, the brain is reserved for more complex task
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• Reflex that involves the brain– The opening and closing of the pupil of the eye
– Automatic response, we have no control of the size of the pupil
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• Another types of automatic response is knee jerk reflex – Involves afferent neuron and efferent neurone
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Knee jerk response
Rubber hammer hits a tendon that connect the quadriceps muscle in the thigh to a bone in the lower leg
The force stretches the quadriceps muscles and stimulate the stretch receptors in the muscles, triggering nerve impulses
Afferent neurones transmitimpulses to the efferentneurones in the spinalcord
The efferent neurones transmit impulses tothe quadriceps muscle, muscle contract, the leg jerking forward
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Reflex arc
Afferent neurones - interneurones – efferent neurones – effector
-- piercing of the skin
Afferen neurone – efferent neurone-effector ---knee jerk reflect
Afferent neurones – brain - interneurone – efferent neurone – effector
--opening and closing of the pupil
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Involuntary action which involves smooth muscles, cardiac muscle or glands
1. The autonomic nervous system
- controls involuntary actions involving :
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* glands
*cardiac muscle
* smooth muscle of the internal organs
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– Connects the medula oblongata and hypothalamus with the internal organs and regulates the internal body processes
– Require no conscious effort Cerebral cortex
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– Impulses are not transfered to the cerebral cortex – we were not aware of the response
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– Enable vital functions – heartbeats, blood circulation – continues during unconsciousness / sleeping
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– Autonomic nervous system can be divided into :• Sympathetic division
• Parasympathetic division
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Sympathetic division
- prepares the body for stressful situations
- increase the pulse rate, blood pressure, breathing rate
-
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slows down the digestive system – more blood is available to carry oxygen to vital organs (heart, brain)
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Parasympathetic division
- prepares the body during ordinary situations / relaxed state
-
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decrease the pulse rate, blood pressure, breathing rate
-stimulate the digestive system to continue breaking down food
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Diseases of the nervous system
1. Parkinson's disease
- affect the muscular movements causing tremors or trembling of the arms, jaws, leg, face
- difficulty maintaining normal postures, impaired balance and coordination
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2. Alzheimer's disease
- neurological disorder causes the loss of reasoning and ability to care fo oneself
- individuals becomes confuse, forgetful, lose ability to read, write, eat, walk and talk
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• The information for involuntary actions does not involve the cerebral cortex– No perception is generated
– We not aware of the response
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The role of Hormones in humans • Hormones are chemical messengers produced
by the endocrine gland
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• Endocrine glands – ductless glands that release hormones directly into the interstitial fluid and then to the bloodstream
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• Hormones only affect specific target cell
• Hormones causes the target cell to respond in a specific manner
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The need for the endocrine system
• The endocrine and nervous system play important roles in maintaining homeostasis
• Some physiological processes need both system too work together, others only involve the endocrine system
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The nervous systemcontrols voluntaryand involuntary actions
conveys impulses
message conductedvia neurones
message are carried between specific location
responses or effects are temporary
message are conveyedrapidly
The endocrine systemcontrols involuntary actions
conveys chemical signals
message are conveyedvia bloodstream
message are carried tovarious destinations
responses or effects are long lasting
message are conveyed slowly
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The human endocrine system
- consist of glands that contain hormones-secreting cells
- the glands secrete different types of hormones involved in specific physiological processes
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Function of hormones
Reproduction
Follicle stimulatinghormone, luteinising hormone, oestrogen,progesterone, androgen
Growth
Growth hormone,thyroid stimulatinghormone, thyroxine
Homeostasis
Insulin, glucagon,antidiuretic, adrenaline
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Endocrine gland
Anterior pituitarygland
Posterior pituitarygland
Thyroid stimulatinghormone (TSH)follicle stimulating hormone (FSH)luteinising hormone (LH)adrenocorticotrophic hormonegrowth hormone (GH)Prolactin (PRL)
Antidiuretic hormone (ADH)Oxytoxin
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Other endocrine glands
• Thyroid gland – Thyroxine
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• Adrenal cortex– Aldosterone
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• Pancreas– Insulin
– Glucagon
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• Ovaries – Oestrogen
– Progesterone
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• Testis – Testosterone
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Regulation of hormone secretion
- endocrine gland release hormones more frequently when stimulated
-
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• hormone secretion is normally regulated to prevent over production or under production
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• Regulation of hormone is controlled by:• Signals from nervous system
• Other hormones
• The level of specific substances in the body
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The regulation of hormone secretion by signal from the nervous system
- pituitary gland is the master of endocrine gland because it secreters hormones that control other endocrine gland
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• The pituitary gland is controlled by hypothalamus
• Posterior pituitary gland contains axons and synaptic terminals of the neurosecretory cells that originate in the hypothalamus
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• Hypothalamus :• Controlling the secretion of hormones from the pituitary
gland
• Link between the nervous system and the endocrine system
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• Maintain homeostasis by receiving impulses of the internal environment
• Have specialised nerve cells called neurosecretory
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Neurosecretory cells in hypothalamus
ADH, oxytoxinpass through the axon into the posterior pituitarycells and stored inthe synaptic terminals
ADH and oxytoxin are secreted intothe bloodstream
Hypothalamic releasing hormones, hypothalamicinhibiting hormones
These hormones are carried in the blood stream to the anterior pituitary
Hypothalamic releasing hormones stimulate the seretion of anterior pituitaryhormones
Hypothalamic inhibiting hormones prevent the secretion of the anterior pituitary hormones
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hypothalamus
Hypothalamic releasing hormones
Hypothalamic inhibiting hormones
Anterior pituitary
Secretion of anteriorPituitary hormones
Inhibition of secretion of Anterior pituitary hormones
ADH and oxytoxin
Posterior pituitarygland
ADH , oxytoxin Secreted into the Blood stream
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The regulation of hormone secretion by other hormones
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hypothalamus
Thyroid releasing hormones
Anterior pituitary gland
Thyroid stimulating hormones
Thyroid gland
Thyroxine hormones Are released
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• The secretion of most hormones is first regulated and controlled by the nervous system
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• Hormones that are released by the pituitary gland are used to stimulate other glands to secrete hormones
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Posterior pituitary
Anteriorpituitary
ADH - kidney tubule
Oxytoxin- smooth musclein the uterus
ACTH-adrenal cortex
TSH- thyroid
FSH, LH- ovaries, testes
GROWTH HORMONE- bone, tissues
PROLACTIN- mammary glands
Pituitary
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• The release of a hormone from the target exerts a negative feedback control
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Thyroid releasing hormone from hypothalamus TRH stimulate the
anterior pituitaryto secrete TSH
TSH stimulates the thyroid gland to secrete thyroxineWhen thyroxine
concentration is high, its inhibit TRH productionfrom the hypothalamusand TSH from the anteriorpituitary
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The regulation of hormone secretion by the level of specific substances in the blood
- the secretion of hormones is regulated by the level of specific substances in the blood
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• Examples :
• Blood glucose level rises, the pancreas produces insulin
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• Insulin increase the glucose uptake by the cell
• Cells metabolise or convert the glucose to glycogen
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• The blood glucose level returns to normal
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The involvement of the nervous and endocrine system in a fight or flight
situation
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Fight or flight situation
Nerve impulses from the hypothalamus stimulate the neurones from the sympathetic division of the autonomic nervous system in the adrenal medulla
Stimulate the adrenal medulla to secrete adrenaline and noradrenaline
Adrenaline and noradrenaline cause an increase in heartbeat, breathing rates, blood pressure, blood glucose level, metabolic activity
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Fight or flight situations
Nerve impulses from hypothalamus
Stimulates the neurones from the symphathethic Division of the autonomic nervous system in the adrenalmedulla
Stimulate the cells of the adrenal medulla to secrete Adrenaline and noradrenaline
Adrenaline and noradrenaline cause increase in heartbeat,Blood pressure, blood glucose level, metabolic activity
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• The hearts contracts vigorously to pump larger amount of oxygen and glucose to the brain and skeletal
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• Skeletal muscle becomes more energised and enable a person to fight or flee immediately from danger
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• The nervous and endocrine system working together to bring immediate response to cope with threat
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Hormon imbalance and related disease
1. growth hormone
- over secretion
– gigantism
- acromegally (adult) – bones, hand, feet, cheek & other tissues enlarge
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- under secretion :
- dwarfism
- genetically enginered growth hormone is given to the children allowing them to attain normal height
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2. Thyroxine
- over secretion :
- increase metabolic rate – excessive sweating, heat intolerence, nervousness, rapid heart rate, weight loss
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- goitre – thyroid gland enlarge – iodine deficiency
- thyroid gland cannot synthesise enough thyroxine, its enlarge in response from pituitary gland
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– Under secretion :• Child - Severe mental retardation (cretinism)
• Adult – myxedema – slow heart rate, low body temperature, sensitive to cold, gain weight easily
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3. Insulin
- Over secretion – hypoglecaemia (low level of glucose in the body)
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- symptoms – fatigue, insomnia, mental confusion, nervousness, mood swings, fainting spells, headaches
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– Under secretion – diabetes mellitus• Abnormally high level of glucose in the blood
• Body do not produce enough insulin or cannot use the insulin that are produced
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• Increase frequency of urination
• Large quantities are produced by genetically engineered bacteria – injected to the patient
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4. ADH
- Over secretion
- high retention of water in the body
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– Under secretion • Diabetes insipidus
• Excrete a large amount of urine
• Always thirsty, drinks frequently
• Water lost in the urine
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Homeostasis in humans
• The maintainance of relatively constant internal environment is known a homeostasis
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• Internal environment consist of phyical factors and chemical factors
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The excretory system
• Primary organs – kidneys– Regulate water and salt balance – excreting more or
les salt, increasing intake or loss of water
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– Regulate osmotic pressure and ionic level in the bloods
– Excrete waste products
– Regulate blood pH
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Waste products
From metabolic reactions - urea, creatinine (from amino acids)- uric acids (from nucleic acids)
Foreign substances in the diet- drugs, toxin
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The human kidney
• Kidneys filter blood and form urine
• Urine exits thorugh the ureter, urinary bladder and urethra
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• Urine consist of :• Water
• Urea
• Disolved waste
• Exces nutrients
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• Kidney has two region :• Renal cortex – outer light red region
• Renal medulla – inner dark red region
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The nephron
- the funcional unit of a kidney
- each kidney – about one million nephrons
-
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- consists of three major parts :
1. glomerulus and its blood vessels
2. Bowman's capsule
3. renal tube
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• Renal tube is made up of :• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule
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• Three basic processes to produce urine:• Ultrafiltration
• Reabsorption
• Secretion
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Ultrafiltration in Bowman's capule
- podocytes and endothelium of the the glomerulus form a filtration membrane
-
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permits the passage of water and solute from the blood into the capsular space
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• Blood pressure is high when it reach the nephron
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• The pressure increase because the afferent arteriole has larger diameter than the efferent arteriole
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• Blood enters the glomerulus– Ultrafiltration take place
– High pressure forces fluid through the filtration membrane into the capsular space
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– Filtration membrane filter certain size of molecules
– Fluid that pass the filtration membrane is called glomerulus filtrate
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• Glomerulus contents :• Water, glucose, amino acids, urea, mineral salts, small
molecule
• Same composition as blood plasma
• No red blood cells, plasma proteins (too large)
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Afferent arteriole
Glomerulus
Efferent arteriole
Efferent arteriole divides into blood capillariessurrounding kidney tubules
Blood capillaries -Peritubular capillaries
Blood capillaries join together to form renal vein
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Reabsorption
- take place when substances move across the walls of the renal tubule into the capillary network
-
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- Chloride ions move out passively
- reabsorption of glucose and amino acids through active transport
-
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- movement of solutes into the capillary network increase the concentration solute in the capillary network
- water moves into the blood capillaries by osmosis
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- Loop of Henle:
- water, sodium, chloride ions are reabsorbed
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- Distal convoluted tubule :
- watery filtrate contains low in salt, high in waste ( urea)
- more water, sodium, chloride ions are reabsorbed
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- Collecting duct :
- filtrate has very little salt, 99% of water has been reabsorbed
- only 1 % of the water leaves as urine
-
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urine moves down the collecting duct
- some urine diffuse out into surrounding fluid and blood ( small size )
-
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45% of the original urea remain to be excreted as urine
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Secretion
- there are waste products in the blood that were not filtered
-
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secretion is a process in which waste and excess substances that were not initially filtered are secreted into the renal tube
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- Secretion at – renal tubule, collecting ducts, distal convoluted tubule
-
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- occurs by active and passive transport
-
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secreted substances :– Hydrogen ions
– Potassium ions (K+)
– Urea
– Creatinine
– Toxin
– drugs
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• Positive feedback mechanism produces a response that intensifies the original change
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• Example :– The release of the oxytoxin which stimulates and
intensifies uterine contraction during labour
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- by adjusting the amount of ions to reabsorb or secretion, the kidneys can regulate chemical composition of the blood
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The constituents of urine
- pH – slightly acidic
- Water – 1-2 litres
- Uric acid - 0.8g
- Cl- - 6.3g
- Creatinine – 1.6 g
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- Na+ - 4 g
- HCO3- - 0.03 g
- Urea – 30 g
- K + - 2 g
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Negative feedback mechanism
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• Internal environment of the human body must be maintain at constant level
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• Internal environment :– Tissue fluid
– Blood
– lymph
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• Factors affecting internal environment:• Blood sugar level
• Body temperature
• Blood osmotic pressure
• Partial pressure of oxygen and carbon dioxide
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Blood sugar level
Body temperature
Blood osmotic pressure
Partial pressure of oxygenand carbon dioxide
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• The maintenance of relatively constant internal environment - Homeostasis
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• Homeostasis is achieved by negative feedback mechanism
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• Whenever changes occur in internal environment our body will initiates a corrective mechanism
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Normal value
Value rise Corrective mechanism
Normal value
Correctivemechanism
Value drops
Negative feedback
Negative feedback
Blood pressure
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• Kidney involves in negative feedback mechanism to maintain homeostasis
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The role of kidneys in Homeostasis
- the body gains and loss water every day
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• Kidney control the water content of the blood at constant level– osmoregulation
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Osmoregulation – the process of maintaining the water content of the blood at constant level
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Homeostasis achieved by regulating the volume of urine production and excretion
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Drinks too much water
Blood osmotic pressure drops below normal
Osmoreceptor cells in hypothalamus are less stimulated
Pituitary glands less stimulated
Less ADH issecreted from pituitaryglands
Low level of ADHcause the distal tubule & collecting duct less permeableto water
Less water is reabsorbed into the blood
The result – increasethe blood osmotic pressureand return to normal
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Low level of ADHcause the distal tubule & collecting duct less permeableto water
Less water is reabsorbed into the blood
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Drinks toolittle
Blood osmotic pressure increasesabove normal
Osmoreceptor cellsin the hypothalamus detect increase in blood osmotic pressure
Osmoreceptor cells in the hypothalamus stimulate pituitary gland to release more ADH
ADH increasesthe permeability of thedistal tubule and collecting duct
More water is reabsorbed from the filtrate into the blood
Blood pressure return to normal
Water content of theurine decreases.Urine more concentrated , dark
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ADH increasesthe permeability of thedistal tubule and collecting duct
More water is reabsorbed from the filtrate into the blood
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• The lower osmotic pressure reduces the activity of the hypothalamic osmoreceptor cells
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• Osmoreceptor cells stop stimulating pituitary gland to secrete more ADH
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Kidney Problem
- kidneys of some people are damaged due to diseases , drug or injury
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Treatment
- Haemodialysis
- kidney transplants
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haemodialysis – the process of filtering blood by using an artificial means that replace the functions of a failed kidney
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– Blood from the artery is passed through the machine which contains a dialyser
– Dialyser has two sections separated by semi permeable membrane
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– Blood passes on one side of the membrane and dialysis solution passes on the other
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– The different concentration gradient between the blood and dialysis solution is such that the waste molecules and excess salts can diffuse through the membrane
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Blood Dialysis solution
Toxin from the blood diffuse through the semi permeable membrane
Required ions andglucose are added into the dialysissolutin
Semi permeable membrane
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• Another treatment for impaired kidney is the transplant of a healthy kidney from a donor to the patient
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The regulation of blood sugar level
- pancreas gland is responsible for maintaining the blood sugar level within 75-110mg/100ml
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- pancreas secrete insulin hormone and glucagons into the bloodstream
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Insulin and glucagons
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High blood sugarconcentration
Low blood sugarconcentration
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• Insulin reduce the blood glucose level
• Glucagon increase the the blood glucose level
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• Both hormone work in opposition to regulate the blood glucose level
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• Diabetes mellitus – Defects in production, release, and reception of
insulin
– The proximal convoluted tubule cannot reabsorb all the glucose from the kidney filtrate
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The regulation of body temperature
- the body temperature fluctuate
- maintains at 37 C
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Changes in the external temp.
Cause initialchange in bodytemp.
Changes detected by
Thermoreceptors in hypothalamusdetect blood temp.
Thermoreceptors in the skin detect externaltemperature
Thermoregulatory centre in the hypothalamus
Smooth musclesin the arterioles
Sweat gland Erector musclesin the skin
Skeletal muscles
Adrenal, thyroid glands
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Internal temp.rises, vasodilation occurswhen smooth muscles around afferent arteriole relax
Increase bloodflows through theskin
Increase the amountof heat radiated and loss by the skin
Temperature rises
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Internal temp. rises
Sweat glands secretesweat to the surface of the skin and evaporate
The body coolsand the internaltemperature drops to set point onceagain The temperature
drop beneath set pointsweating stop, body heat conserved
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Internal temperature rises above the setpoint
Erector muscles in the skill relaxlowering the skin hair, warm air is not trapped
Internal temperaturedrops below the set point, erector muscle contract, raising the skinhairs, trapping layer of warm air
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Internal temperaturerise above set point
Skeletal muscle are not stimulated,shivering does not occur
Internal temperaturedrops beneath setpoint
Skeletal musclesare stimulated, shiveringoccurs
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Internal temperature rise above the set point
Adrenal and thyroidglands are less stimulatedto secrete adrenaline and thyroxine
The metabolic rateis low, no excess heatis generated
Internal temperature drops beneath belowthe set point
Adrenal and thyroid glands are stimulated to secrete more adrenalineand thyroxine
Metabloc rate increase, more heat is generated
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Practising a healthy lifestyle
• Drugs can alter brain functions and the rates at which neurones releases neurotransmitter
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• The abuse of drugs reuslt in a tolerance of the drug
• More and more drugs is needed to get the same initial effect on the person
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• Types of drugs:• Stimulants
• Depressants
• Hallucinogens
• Narcotics
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• Stimulants – Increase activity of the central nervous system
– Blocks the removal of pleasure -inducing neurotransmitters
– e.g. - cocaine
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• Depressants – Slow down the activity of the central nervous system
– Slow down the transmission of nerve impulses
– e.g : alcohol
– Inhibits the release of ADH
– Large volumes of urine
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• Hallucinogens – LSD (D-lysergic acid diethylamide)
– See, hear and percieve things that do not exist
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• Narcotics – Feeling euphoria, block pain signals, slow down
normal brain function
– e.g.: heroine, morphine
– Mimick neurotransmitter binding to their receptor sites
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Plant Hormones
• Types of plant hormones :– Auxins
– ethylene
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• Plant produce hormones for growth and development
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Auxins
- promote cell elongation cell lengthening
- produced in apical meristem at the tip of the shoots
- result – increase the stem length by increasing the rate of cell division
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• The role of auxins in phototropism:– Growth of plants towards light is caused by unequal
distribution of auxins in the shoot
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.......... ...........
Even distributionof auxin
Sunlight from all side
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• When a plant is exposed to light from one direction
• Auxin build up on the side in the shade, and stimulate the growth of the side that do not receive sunlight
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• The side that do not receive sunlight divide faster and elongate faster than the side that receive sunlight
• Result – the shoot bending towards the lights
• Auxin result in positive phototropism in plant shoots
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The role of auxin in geotropism
- if the seeds is buried horizontally
- light and gravity causes the auxins to be transported to the lower side of the root or shoot
-
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• The auxin that accumulate at the lower side of the shoot stimulate the elongation of the shoot
• Result – the shoot bends upwards
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• The auxin that accumulate at the lower side of the root inhibits the elongation of the root
• The upper side of the root elongated faster than the lower side of the root
• The root bend downwards
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• When the root bend downward, the auxin distribution becomes equal on all side
• The roots continue to grow straight downwards
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• Auxin are also used to stimulate the growth of adventitious roots from the stem– Used to trigger the adventitious roots for commercial
plants
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• Induce the development of fruit without fertilisation or parthenocarpy
• Parthenocarpy is used to produce seedles fruits
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Ethylene
- a plant hormone which is synthesised during the ripening of the fruit
- synthesised in – fruits, leaves, stem
- in the form of gas
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- functions :
- speeds up the ripening of fruits
- stimulating the production of cellulase
- cellulase hydrolyses the cellulose in plants making it soft
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- promotes the breakdown of complex carbohydrates into simple sugar
- make fruits taste sweet
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• Placing a basket of ripe mangoes with unripe bananas can induce ripening of banana