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COORDINATION AND RESPONSE

• Living organisms have the ability to detect the internal and external environment changes

The changes which cause response in the body are called stimuli

• Two types of stimuli:

• (a) internal stimuli• Changes in blood pressure, sugar level

• (b) external stimuli– Changes in light intensity, sound, temperature,

pressure, touch

Stimuli receptors Effector

Response

• A response is the ways an organisms react after stimulus is detected

Stimuli receptors Effector

Response

When stimuli are detected and eventually result in reponse it is called coordination

Stimuli receptors Effector

Response

• Coordination ensures the activities of an organism function as an intergrated whole

Coordination and response

Nervous system Endocrine system

Nervous system

Sensory receptors

Intergrating centre

effectors

PeripheralNervous system

efector

Central nervoussystem

• Sensory receptors – Detect changes in the external environment

• Found in eyes, nose, ears, tongue, skin

- Detect changes in the internal environment

Located in specific internal organs

• Examples of external environment receptors:– Light sensitive cell in the retina

– Temperature and touch receptor in the skin

– Vibration sensitive cells in the ears

• Examples of internal environment receptors :–Cells sensitive to level of carbon dioxide in the

blood, blood osmotic pressure

Pancreatic cells detect blood glucose level

• Intergrating centre– Intergrating centre is the central nervous system

( brain, spinal cord)

Intergration happens when information from the receptors is interpreted to bring appropriate response

• Effectors – Carry out the responses to stimuli

– Effectors – muscle cells, glands

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

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

Change in the blood temperature

Detected by temperature

sensitive cells in hypothalamus

Impulses are carried by afferent nerves to the thermoregulatory centre in hypothalamus

The role of the human nervous system

Human nervous system

Central nervous system

Peripheral nervous system

brain Spinal cord Cranial nerves

spinal nerves

Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves which emerge from segments of the spinal cord

• Nervous system performs three main functions :– 1. sensory

– 2. intergrative

– 3. motor

• sensory receptors detect stimuli – initiate impulses that carry information to the CNS

• CNS – initiate suitable responses

• Motor commands from the CNS are transmitted to the effectors - muscles, glands

• Human brain :– Cerebrum

– Cerebellum

– Medulla oblongata

– Thalamus

– Hypothalamus

Cerebral cortex

Cerebrum

- largest, most complex part of the brain

- divided into two – left hemisphere - right hemisphere

• Left hemisphere – controls movements on the right side of the body

Functions – receive the sensory input and carries out integrative functions before initiating motor response

– Coordinates the activities other parts of the brain

• Outer region of the cerebrum - cerebral cortex– Many folds to increase surface area

Cerebral cortex

– Function –• directs voluntary muscle movement, result in sensory

perception (know what he sees, hears, smell)

Mental abilities – learning, memorising, reasoning, language skills, mathematic skills, imagination, artistic talents, personality

• Damage to this area can cause specific defect – speech impairment, reading difficulty, paralyse

• Cerebellum– The coordinating centre for body movements

– Receieves information from sensory receptor from all parts of the body and from the cerebrum

– Evaluate infromation and relays the need for coordinated movements back to the cerebrum

– Cerebrum then sends appropriate commands to the muscles

• Medulla oblongata– Function –

• regulates the internal body processes that do not require conscious effort – heartbeat, breathing, vasoconstriction

• Reflex centre for vomiting, coughing, sneezing, hiccupping, swallowing

• Hypothalamus– Function – homeostatic regulation

– Coordintion centre for regulating sleep, hunger, thirst, body temperature, water balance, blood presure

– Control centre for endocrine system (hormone)

• Pituitary gland– Function – secretes hormones that influence other

glands and body functions

The hypothalamus controls the release of several hormone from the pituitary gland

• Thalamus – Function –

• sorting the incoming and outgoing information in the cerebral cortex

• Enhancing and blocking signals from the sensory receptors to the cerebrum

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

Dorsal rootganglion

• Spinal nerves emerge from the spinal cord through two branches/ roots:

• Dorsal roots

• Ventral rootsDorsal root

• Dorsal roots – Contains axon of the afferent neurons which conduct

nerve impulses from the sensory receptors to the spinal cord

Dorsal rootganglion

– Dorsal root ganglion contains the cell bodies of afferent neurons

• Ventral root– Contains the axons of the efferent neurons which

conduct impulses away from the spinal cord to the effector

Dorsal rootganglion

• The spinal cord :– Processes sensory information and send out

responses through the efferent neurones

– Contains neurones that transfer signals to and from the brain

– Neural pathway for reflexes

receptor Neuron afferent Spinal cord

brain

Neuron efferent

Effectors /muscle

Pathway off the impulse

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

• Three types of neurones:• Afferent neurones

• Efferent neurones

• internuerones

• Afferent neurones – Carry sensory information from the receptor cells to

the brain and spinal cord

Movement of impulse

• Efferent neurones – Carry information from the brain or spinal cord to the

effectors (muscle, gland cells)

Movement of impulse

• 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

The transmission pathway of information

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

The transmission of information along the neurones

• The transmission of information along the neurones is through electical signals known as nerve impulses

• Impulse – positive charges that travel along the axon to the synaptic terminal

• A neurones will not transmit impulses if the stimulation is not strong enough

Afferent neurones interneurones Efferent neuronesimpulse impulse

Receptor

Brain

impulse

Stimulus

impulse

Interpret, Integration,Response

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

The transmission of information across synapses

• Neurones are not connected to each other

• 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

• Synapse is the site where two neurones or a neurone and an effector cell communicate

• Electrical signals must be transmitted across the synaptic cleft to an adjacent cell

• The transmission of nerve impulses across the synaptic cleft occurs with the help of neurotransmitter (chemical substances)

• Neurotransmitter is stored in the synaptic vesicles

• The transmission of impulses involves the conversion of electrical signal into chemical signals

Electrical signal

Chemical signal

Electrical signal

(neurotransmitter)

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

• The transmission of nerve impulses across synapses is an active process which required energy

• Synaptic terminal contains abundant mitochondria to generate energy for transmission of nerve impulses

• After the neurotransmitter has relayed its message – Broken down by enzymes

– Taken up again by the synaptic terminal and recycled

• Examples of neurotransmitter :• Acetylcholine

• Noradrenaline

• Serotonin

• dopamine

• The functions of synapses :• Controlling and intergrating the nerve impulses

• Facilitating the transmission of nerve impulses in one direction

– Synaptic vesicles only present in synaptic terminals

– Only presynaptic membrane can discharge neurotransmitter

– Receptors only present in postsynaptic membranes

Action of skeletal muscle

Voluntary action Involuntary action

• Voluntary action of the skeleton muscle– Voluntary actions are under conscious control

– Information that reaches cerebral cortex or conscious level result in a perception of the external environment

Stimulus receptor Afferent neurone

Cerebral cortex

Efferent neurone

effector

response

• Involuntary action that involves the skeletal muscles: the reflex arc– Involves skeletal muscle that does not require

consciuos effort

• Example – if a finger touch a hot stove, the reactions is to pull the finger away without having to thing

• Rapid, automatic

• The nerve pathway involved is called reflex arc

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

The importance of reflexes

- Cut the time of response

- the pain is slightly delayed after the response has been made

• Only involves the spinal cord, the brain is reserved for more complex task

• 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

• Another types of automatic response is knee jerk reflex – Involves afferent neuron and efferent neurone

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

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

Involuntary action which involves smooth muscles, cardiac muscle or glands

1. The autonomic nervous system

- controls involuntary actions involving :

* glands

*cardiac muscle

* smooth muscle of the internal organs

– Connects the medula oblongata and hypothalamus with the internal organs and regulates the internal body processes

– Require no conscious effort Cerebral cortex

– Impulses are not transfered to the cerebral cortex – we were not aware of the response

– Enable vital functions – heartbeats, blood circulation – continues during unconsciousness / sleeping

– Autonomic nervous system can be divided into :• Sympathetic division

• Parasympathetic division

Sympathetic division

- prepares the body for stressful situations

- increase the pulse rate, blood pressure, breathing rate

-

slows down the digestive system – more blood is available to carry oxygen to vital organs (heart, brain)

Parasympathetic division

- prepares the body during ordinary situations / relaxed state

-

decrease the pulse rate, blood pressure, breathing rate

-stimulate the digestive system to continue breaking down food

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

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

• The information for involuntary actions does not involve the cerebral cortex– No perception is generated

– We not aware of the response

The role of Hormones in humans • Hormones are chemical messengers produced

by the endocrine gland

• Endocrine glands – ductless glands that release hormones directly into the interstitial fluid and then to the bloodstream

• Hormones only affect specific target cell

• Hormones causes the target cell to respond in a specific manner

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

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

The human endocrine system

- consist of glands that contain hormones-secreting cells

- the glands secrete different types of hormones involved in specific physiological processes

Function of hormones

Reproduction

Follicle stimulatinghormone, luteinising hormone, oestrogen,progesterone, androgen

Growth

Growth hormone,thyroid stimulatinghormone, thyroxine

Homeostasis

Insulin, glucagon,antidiuretic, adrenaline

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

Other endocrine glands

• Thyroid gland – Thyroxine

• Adrenal cortex– Aldosterone

• Pancreas– Insulin

– Glucagon

• Ovaries – Oestrogen

– Progesterone

• Testis – Testosterone

Regulation of hormone secretion

- endocrine gland release hormones more frequently when stimulated

-

• hormone secretion is normally regulated to prevent over production or under production

• Regulation of hormone is controlled by:• Signals from nervous system

• Other hormones

• The level of specific substances in the body

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

• The pituitary gland is controlled by hypothalamus

• Posterior pituitary gland contains axons and synaptic terminals of the neurosecretory cells that originate in the hypothalamus

• Hypothalamus :• Controlling the secretion of hormones from the pituitary

gland

• Link between the nervous system and the endocrine system

• Maintain homeostasis by receiving impulses of the internal environment

• Have specialised nerve cells called neurosecretory

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

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

The regulation of hormone secretion by other hormones

hypothalamus

Thyroid releasing hormones

Anterior pituitary gland

Thyroid stimulating hormones

Thyroid gland

Thyroxine hormones Are released

• The secretion of most hormones is first regulated and controlled by the nervous system

• Hormones that are released by the pituitary gland are used to stimulate other glands to secrete hormones

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

• The release of a hormone from the target exerts a negative feedback control

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

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

• Examples :

• Blood glucose level rises, the pancreas produces insulin

• Insulin increase the glucose uptake by the cell

• Cells metabolise or convert the glucose to glycogen

• The blood glucose level returns to normal

The involvement of the nervous and endocrine system in a fight or flight

situation

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

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

• The hearts contracts vigorously to pump larger amount of oxygen and glucose to the brain and skeletal

• Skeletal muscle becomes more energised and enable a person to fight or flee immediately from danger

• The nervous and endocrine system working together to bring immediate response to cope with threat

Hormon imbalance and related disease

1. growth hormone

- over secretion

– gigantism

- acromegally (adult) – bones, hand, feet, cheek & other tissues enlarge

- under secretion :

- dwarfism

- genetically enginered growth hormone is given to the children allowing them to attain normal height

2. Thyroxine

- over secretion :

- increase metabolic rate – excessive sweating, heat intolerence, nervousness, rapid heart rate, weight loss

- goitre – thyroid gland enlarge – iodine deficiency

- thyroid gland cannot synthesise enough thyroxine, its enlarge in response from pituitary gland

– Under secretion :• Child - Severe mental retardation (cretinism)

• Adult – myxedema – slow heart rate, low body temperature, sensitive to cold, gain weight easily

3. Insulin

- Over secretion – hypoglecaemia (low level of glucose in the body)

- symptoms – fatigue, insomnia, mental confusion, nervousness, mood swings, fainting spells, headaches

– 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

• Increase frequency of urination

• Large quantities are produced by genetically engineered bacteria – injected to the patient

4. ADH

- Over secretion

- high retention of water in the body

– Under secretion • Diabetes insipidus

• Excrete a large amount of urine

• Always thirsty, drinks frequently

• Water lost in the urine

Homeostasis in humans

• The maintainance of relatively constant internal environment is known a homeostasis

• Internal environment consist of phyical factors and chemical factors

The excretory system

• Primary organs – kidneys– Regulate water and salt balance – excreting more or

les salt, increasing intake or loss of water

– Regulate osmotic pressure and ionic level in the bloods

– Excrete waste products

– Regulate blood pH

Waste products

From metabolic reactions - urea, creatinine (from amino acids)- uric acids (from nucleic acids)

Foreign substances in the diet- drugs, toxin

The human kidney

• Kidneys filter blood and form urine

• Urine exits thorugh the ureter, urinary bladder and urethra

• Urine consist of :• Water

• Urea

• Disolved waste

• Exces nutrients

• Kidney has two region :• Renal cortex – outer light red region

• Renal medulla – inner dark red region

The nephron

- the funcional unit of a kidney

- each kidney – about one million nephrons

-

- consists of three major parts :

1. glomerulus and its blood vessels

2. Bowman's capsule

3. renal tube

• Renal tube is made up of :• Proximal convoluted tubule

• Loop of Henle

• Distal convoluted tubule

• Three basic processes to produce urine:• Ultrafiltration

• Reabsorption

• Secretion

Ultrafiltration in Bowman's capule

- podocytes and endothelium of the the glomerulus form a filtration membrane

-

permits the passage of water and solute from the blood into the capsular space

• Blood pressure is high when it reach the nephron

• The pressure increase because the afferent arteriole has larger diameter than the efferent arteriole

• Blood enters the glomerulus– Ultrafiltration take place

– High pressure forces fluid through the filtration membrane into the capsular space

– Filtration membrane filter certain size of molecules

– Fluid that pass the filtration membrane is called glomerulus filtrate

• Glomerulus contents :• Water, glucose, amino acids, urea, mineral salts, small

molecule

• Same composition as blood plasma

• No red blood cells, plasma proteins (too large)

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

Reabsorption

- take place when substances move across the walls of the renal tubule into the capillary network

-

- Chloride ions move out passively

- reabsorption of glucose and amino acids through active transport

-

- movement of solutes into the capillary network increase the concentration solute in the capillary network

- water moves into the blood capillaries by osmosis

- Loop of Henle:

- water, sodium, chloride ions are reabsorbed

- Distal convoluted tubule :

- watery filtrate contains low in salt, high in waste ( urea)

- more water, sodium, chloride ions are reabsorbed

- Collecting duct :

- filtrate has very little salt, 99% of water has been reabsorbed

- only 1 % of the water leaves as urine

-

urine moves down the collecting duct

- some urine diffuse out into surrounding fluid and blood ( small size )

-

45% of the original urea remain to be excreted as urine

Secretion

- there are waste products in the blood that were not filtered

-

secretion is a process in which waste and excess substances that were not initially filtered are secreted into the renal tube

- Secretion at – renal tubule, collecting ducts, distal convoluted tubule

-

- occurs by active and passive transport

-

secreted substances :– Hydrogen ions

– Potassium ions (K+)

– Urea

– Creatinine

– Toxin

– drugs

• Positive feedback mechanism produces a response that intensifies the original change

• Example :– The release of the oxytoxin which stimulates and

intensifies uterine contraction during labour

- by adjusting the amount of ions to reabsorb or secretion, the kidneys can regulate chemical composition of the blood

The constituents of urine

- pH – slightly acidic

- Water – 1-2 litres

- Uric acid - 0.8g

- Cl- - 6.3g

- Creatinine – 1.6 g

- Na+ - 4 g

- HCO3- - 0.03 g

- Urea – 30 g

- K + - 2 g

Negative feedback mechanism

• Internal environment of the human body must be maintain at constant level

• Internal environment :– Tissue fluid

– Blood

– lymph

• Factors affecting internal environment:• Blood sugar level

• Body temperature

• Blood osmotic pressure

• Partial pressure of oxygen and carbon dioxide

Blood sugar level

Body temperature

Blood osmotic pressure

Partial pressure of oxygenand carbon dioxide

• The maintenance of relatively constant internal environment - Homeostasis

• Homeostasis is achieved by negative feedback mechanism

• Whenever changes occur in internal environment our body will initiates a corrective mechanism

Normal value

Value rise Corrective mechanism

Normal value

Correctivemechanism

Value drops

Negative feedback

Negative feedback

Blood pressure

• Kidney involves in negative feedback mechanism to maintain homeostasis

The role of kidneys in Homeostasis

- the body gains and loss water every day

• Kidney control the water content of the blood at constant level– osmoregulation

Osmoregulation – the process of maintaining the water content of the blood at constant level

Homeostasis achieved by regulating the volume of urine production and excretion

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

Low level of ADHcause the distal tubule & collecting duct less permeableto water

Less water is reabsorbed into the blood

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

ADH increasesthe permeability of thedistal tubule and collecting duct

More water is reabsorbed from the filtrate into the blood

• The lower osmotic pressure reduces the activity of the hypothalamic osmoreceptor cells

• Osmoreceptor cells stop stimulating pituitary gland to secrete more ADH

Kidney Problem

- kidneys of some people are damaged due to diseases , drug or injury

Treatment

- Haemodialysis

- kidney transplants

haemodialysis – the process of filtering blood by using an artificial means that replace the functions of a failed kidney

– Blood from the artery is passed through the machine which contains a dialyser

– Dialyser has two sections separated by semi permeable membrane

– Blood passes on one side of the membrane and dialysis solution passes on the other

– The different concentration gradient between the blood and dialysis solution is such that the waste molecules and excess salts can diffuse through the membrane

Blood Dialysis solution

Toxin from the blood diffuse through the semi permeable membrane

Required ions andglucose are added into the dialysissolutin

Semi permeable membrane

• Another treatment for impaired kidney is the transplant of a healthy kidney from a donor to the patient

The regulation of blood sugar level

- pancreas gland is responsible for maintaining the blood sugar level within 75-110mg/100ml

- pancreas secrete insulin hormone and glucagons into the bloodstream

Insulin and glucagons

High blood sugarconcentration

Low blood sugarconcentration

• Insulin reduce the blood glucose level

• Glucagon increase the the blood glucose level

• Both hormone work in opposition to regulate the blood glucose level

• Diabetes mellitus – Defects in production, release, and reception of

insulin

– The proximal convoluted tubule cannot reabsorb all the glucose from the kidney filtrate

The regulation of body temperature

- the body temperature fluctuate

- maintains at 37 C

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

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

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

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

Internal temperaturerise above set point

Skeletal muscle are not stimulated,shivering does not occur

Internal temperaturedrops beneath setpoint

Skeletal musclesare stimulated, shiveringoccurs

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

Practising a healthy lifestyle

• Drugs can alter brain functions and the rates at which neurones releases neurotransmitter

• 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

• Types of drugs:• Stimulants

• Depressants

• Hallucinogens

• Narcotics

• Stimulants – Increase activity of the central nervous system

– Blocks the removal of pleasure -inducing neurotransmitters

– e.g. - cocaine

• 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

• Hallucinogens – LSD (D-lysergic acid diethylamide)

– See, hear and percieve things that do not exist

• Narcotics – Feeling euphoria, block pain signals, slow down

normal brain function

– e.g.: heroine, morphine

– Mimick neurotransmitter binding to their receptor sites

Plant Hormones

• Types of plant hormones :– Auxins

– ethylene

• Plant produce hormones for growth and development

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

• The role of auxins in phototropism:– Growth of plants towards light is caused by unequal

distribution of auxins in the shoot

.......... ...........

Even distributionof auxin

Sunlight from all side

• 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

• 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

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

-

• The auxin that accumulate at the lower side of the shoot stimulate the elongation of the shoot

• Result – the shoot bends upwards

• 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

• When the root bend downward, the auxin distribution becomes equal on all side

• The roots continue to grow straight downwards

• Auxin are also used to stimulate the growth of adventitious roots from the stem– Used to trigger the adventitious roots for commercial

plants

• Induce the development of fruit without fertilisation or parthenocarpy

• Parthenocarpy is used to produce seedles fruits

Ethylene

- a plant hormone which is synthesised during the ripening of the fruit

- synthesised in – fruits, leaves, stem

- in the form of gas

- functions :

- speeds up the ripening of fruits

- stimulating the production of cellulase

- cellulase hydrolyses the cellulose in plants making it soft

- promotes the breakdown of complex carbohydrates into simple sugar

- make fruits taste sweet

• Placing a basket of ripe mangoes with unripe bananas can induce ripening of banana