Thursday, July 29, 2010

PBL-Group 1
Group members

• Nur Hidayah Binti Shaari (D20071029446)

• Muna Munirah Binti Haji Zakaria (D2007109562)

• Nor Fadhillah Binti Ramli ( D20071029484)

• Mohd Zulhusni Bin Zulkifli (D20071029461)

What is CNS?
Divided into 2 parts:-
  • Brain
  • Spinal cord

Function of spinal cord?
It has 2 main function:
-center for many reflex action
-means of communication between the brain and spinal nerves
-contains motor areas and sensory areas
It can be divided into:-
Forebrain- cerebrum and diencephalon
Midbrain- midbrain(parts of the brain stem)
Hindbrain- Pons,cerebellum and medulla oblongata
Function of brain:-
Function of
Center of intelect,memory, conciousness and language and also control sensation.

Develops into:-
  • Epithalamus
  • Thalamus
  • Hypothalamus
  • Thalamus: main input center for sensory information going to the cerebrum and the main output center for motor information
  • Hypothalamus: regulate a widw variety of physiological processes : maintainance body temperature,feeding
Midbrain(part of brainstem)
Comprising the medula oblongata
  • Control and integrate reflex activities,eg: respiration and breathing
  • Receives sensory input from eyes,ears and muscles
  • Connects various parts of brain with one another
  • Contain respiratory and sleep center
What causes coma?
The reticular activating system(RAS) is a neutral pathway between the brain stem and thalamus.
The RAS received message from neuron in the spinal cord and from many other part of the nervous system and communicate with the cerebral cortex by complex neuron cicuit.
Component of the RAS help regulate concsiousness
When certain neuron of the RAS bombard the cerebral cortex with stimuli, the individual feels alert and can focus on specific talk. If the RAS is severely damaged, the indivedual may past into a deep permanent coma.


PBL-Group 1

Group members

• Nur Hidayah Binti Shaari (D20071029446)

• Muna Munirah Binti Haji Zakaria (D2007109562)

• Nor Fadhillah Binti Ramli ( D20071029484)

• Mohd Zulhusni Bin Zulkifli (D20071029461)

task 2

Learning issues
1.      Why does sedative types of medicine have shorter duration compared to others type of medicine?
Sedative types of medicine have shorter duration compared to others type of medicine which this drugs can  relieve anxiety. At high doses, many of these sedative drugs can cause unconsciousness and death. These drugs work in the brain by binding to the neurotransmitter gamma-aminobutyric acid (GABA). Neurotransmitters help to regulate the speed at which nerve impulses travel. When the amount of GABA increases, the speed of nerve transmissions decreases. These drugs depress the nervous system and cause relaxation of skeletal muscle.

2.      How would medicine affect the function of neurotransmitter?

Drugs may also alter synaptic transmission by directly affecting the postsynaptic receptors. Some drugs activate receptors, and others block them. While THC (the main psychoactive chemical in marijuana) and morphine activate their specific receptors, other drugs block specific receptors. Caffeine, the mild stimulant found in coffee and some soft drinks, exerts its effects by preventing a neurotransmitter/neuromodulator called adenosine from binding to its receptor. Normally, the binding of adenosine to its receptor causes sedation; it is a natural sleep-inducer. Instead of causing sedation, the blocking of the adenosine receptors with caffeine leads to an increase in activity and arousal levels.
The actions of some drugs are very complex. LSD, for example, acts on serotonin receptors. Serotonin, an important neurotransmitter in many brain regions, is involved in regulating a wide variety of functions including mood and basic survival functions such as sleeping and eating. Scientists continue to study how hallucinogens act, but apparently LSD activates some serotonin receptors (LSD acts as a receptor agonist) and blocks other serotonin receptors (LSD acts as a receptor antagonist).
A third way to affect synaptic transmission is to alter the removal of neurotransmitters from the synapse. Cocaine and amphetamines work this way (this is the second way in which amphetamines can alter neurotransmission).Both drugs block the dopamine transporter (reuptake pump) that removes dopamine from the synapse. The result is a fairly rapid rise of dopamine in the synapse, leading to feelings of euphoria and well-being. There are no drugs of abuse that block enzymatic destruction of neurotransmitters, although some antidepressants work by this mechanism.

3.What are the effect of different quantity of dose?

For drugs to exert their effects, a person must take them into the body and absorb them into the bloodstream. Some of these effects relate to the amount of the drug taken. For example, at low doses, no effect (or response) can be observed or measured. Once a certain amount of the drug enters the bloodstream, a response can then be measured. This point is known as the threshold.
At doses of the drug below the threshold amount, there is too little of the drug in the body to cause neurons to be activated. For example, there may not be enough heroin in the body to bind to opiate receptors in sufficient amounts to cause a change in neuronal activity. As the amount of drug taken increases, so does the response. A response cannot continue to increase infinitely, however. At some point, the response to a given amount of drug will reach a plateau, or a maximum level. To continue our example, when levels of opiates are very high in the blood, many opiate receptors have heroin bound to them and the neurons are already activated; no additional activation is possible. At higher doses, opiates are toxic and can cause a fatal response by halting respiration.

1.      What is the chemical, that contain in each type of medicine and the side effect?

a)      Ponstan
Ponstan belongs to the family of drugs known as a nonsteroidal anti-inflammatory drug (NSAID) medicine and commonly used for the treatment or prevention of the symptoms of inflammation and eases mild to moderate pain. Ponstan is also used to reduce fever and relieves the symptoms of rheumatoid arthritis (rheumatism), osteoarthritis, menstrual cramps or premenstrual pain and swelling. Ponstan works by blocking the action of a substance in the body known as cyclo-oxygenase.
Ponstan is more useful medicine for the treatment and relief of those patients who suffered to the problems of the symptoms of dysmenorrhoea, menorrhagia, Toothache, Pain following surgery and Muscle pain (myalgia).
Ponstan always takes under doctor’s guidance. The recommended doses of Ponstan will be different for different patients, according to the requirements of each patient; you continue to take it for as long as your doctor prescribes. If you can not tolerate the recommended dosage, your doctor can prescribe a dose that sufficient for you. Take Ponstan exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor. Ponstan is being manufactured by Elan Pharma and is available in 250mg capsules. Ponstan is also available in generic form known as Mefenamic acid Capsules. Ponstan may also be used for relieves other conditions that determined by your doctor or consultant.
Ponstan belongs to the family of drugs known as a nonsteroidal anti-inflammatory drug (NSAID) medicine and commonly used for the treatment or prevention of the symptoms of inflammation and eases mild to moderate pain. Ponstan is works by blocking the action of a substance in the body called cyclo-oxygenase. Cyclo-oxygenase is an enzyme involved in the production of chemicals in the body as prostaglandins. Prostaglandins cause pain, swelling and inflammation. By blocking the action of cyclo-oxygenase, Ponstan stops the production of these inflammatory prostaglandins, and therefore reduces inflammation and pain. Ponstan decreases fever by adjusting the body's thermostat in the brain. Ponstan blocks production and release of chemicals that cause pain and inflammation.
Possible side effects that occurs during the uses of Ponstan:
b)      Allergic reactions
c)      Headache
d)     Bladder pain
e)      Bloody or cloudy urine
f)       Problem with urination
g)      Burning or painful urination

b)      Voltaren
Voltaren (diclofenac sodium enteric-coated tablets) is a benzene-acetic acid derivative. Voltaren is available as delayed-release (enteric-coated) tablets of 75 mg (light pink) for oral administration. The inactive ingredients in Voltaren are including hydroxypropyl methylcellulose, iron oxide, lactose, magnesium stearate, methacrylic acid copolymer, microcrystalline cellulose, polyethylene glycol, povidone, propylene glycol, sodium hydroxide, sodium starch glycolate, talc, titanium dioxide.
c)      Diazepam
Diazepam is in a group of drugs called benzodiazepines (ben-zoe-dye-AZE-eh-peens). Diazepam affects chemicals in the brain that may become unbalanced and cause anxiety.
Diazepam is used to treat anxiety disorders, alcohol withdrawal symptoms, or muscle spasms. Diazepam is sometimes used with other medications to treat seizures.
Diazepam may also be used for other purposes not listed in this medication guide
If overdose diazepam Overdose symptoms may include extreme drowsiness, confusion, limp or weak muscles, fainting, shallow breathing, or breathing that stops.

d)     Panadol Active Fast (Paracetamol)
Panadol capsules, tablets and soluble tablets and Panadol ActiFast tablets all contain the active ingredient paracetamol.
                 e) Propofol
Propofol is a drug that reduces anxiety and tension, and promotes relaxation and sleep or loss of consciousness. The primary effect of propofol is potentiation of GABA-A receptors.  Similar to barbiturates and benzodiazepines, propofol has been shown to produce rewarding and reinforcing effects in animals.  Sub-anesthetic and anesthetic doses of propofol have been shown to increase dopamine concentrations in the nucleus accumbens (brain reward system) in rats. 
Propofol has a fast onset of action and crosses the blood-brain barrier very quickly. Its short duration of action is due to rapid distribution from central nervous system to other tissues.  Approximately 70% of the dose is excreted in the urine within 24 hours and 90% is excreted within 5 days of administration.
Propofol has a narrow window of safety.  Induction of anesthesia with propofol is associated with cessation of breathing in some adults and children.  Prolonged high dose infusions of propofol for sedation in adults and children have been associated with cessation of breathing, breakdown of heart muscle, and heart and kidney failure leading to death in some cases, referred as “Propofol Infusion Syndrome”.  Propofol abuse may also cause accumulation of fluid in the lungs, cardio-respiratory depression and death.  There is no antagonist or reversal medication for propofol toxicity

2.      Why the ponstan (200 mg) takes short duration to recover illness compare with panadol active fast?
Prostaglandins are produced by the body in response to injury and certain diseases. One of their actions is to sensitise nerve endings, so that when the injury is stimulated it causes pain (presumably to prevent us from causing further harm to the area).
As paracetamol reduces the production of these nerve sensitising prostaglandins it is thought it may increase our pain threshold, so that although the injury remains, we can feel it less. Like paracetamol, NSAIDs or Non Steroidal Anti-Inflammatory Drugs in example Ponstan also inhibit prostaglandin synthesis, however its action starts by blocking its mother enzyme cyclooxygenase which accounts for both pain and inflammation. This is the main difference between paracetamol and Ponstan. That is the reason why it takes short duration time.

Action Plan
·         Surf internet
·         Reference books
·         Discussion

PBL-Group 1

Group members

• Nur Hidayah Binti Shaari (D20071029446)

• Muna Munirah Binti Haji Zakaria (D2007109562)

• Nor Fadhillah Binti Ramli ( D20071029484)

• Mohd Zulhusni Bin Zulkipli (D20071029461)

1. Why ion control the electrical signal in brain.

• Sodium

• Potasium

2. What the mechanisme involve that facilitated how two ion channels collaborate in the control of electrical signals in the brain.

The mechanism that involves is the action of the sodium potassium pump. Sylvia S. Mader(2006) says that sodium potassium pump is a membrane protein that actively transport Na+ out and K+ into the axon. The work of the pump the will maintain the enequal distribution of Na+ and k+ across the membrane. The mechanism goes like this,

- Cells pump extra potassium into their interiors and pump extra sodium out to the surrounding fluid.

- Electrical impulses in neurons are created when these ions are allowed to return to their original locations by passing rapidly through channels in nerve cells' outer membranes.

- Nerve cells possess wire-like extensions, called axons, which initiate these impulses and carry them from one cell to the next.

The electrical signal in the brain is actually been transmitted uses the information send by the nerve impulses occurs as the action potential occurs. The action potential is a rapid change in polarity across and axomembrane, Sylvia S. Mader (2006).

When an action potential occur, the gates of sodium channel open and  depolarization occurs. The when the gates of pottasium channel open. The repolarization occurs.

  •       What happen in CNS?

CNS is actually make up by the brain and the spinal cord. Here the sensory information is received and the motor control is initiated, sylvia S. Mader (2006)

  •  Why CNS only exist in vertebrate?

 As we know, The CNS is made up by brain and spinal cord. CNS is only exist in vetebrate as  both the spinal cord and the brain is surround by vetebrae. Usually the invetebrae are lack of brain. Thus the did not have CNS.

  •     What is the factor that causes epileptic seizures, pain and abnormal muscle movement.

Some people have mutations in potassium channels that decrease this control, causing excessive nerve firing manifested as epileptic seizures and uncontrolled muscle movements called myokymia and ataxia.

Sources: News

  •      How the the electrical impulses in neurons are created.

Nerve impulses are electrical as they run along the nerve. They then become chemical as they travel over the synaptic cleft. When a neuron receives a stimulus of sufficient strength the electrical current moves along the dendrite and axon to the neurotransmitter swellings. The movement of ions causes these electrical impulses.