Function of R.B.C's

1. Transport of Gases:

R.B.C's play an important role in the transport of gases such as O2 and CO2.

i. Transport of O2:

When we inhale O2. Then this O2 reach the lungs where hemoglobin which is the chief component of erythrocyte combines with O2 to form oxy-hemoglobin. Actually the function of erythrocytes is to carry the O2 in the form of oxy-hemoglobin to various time of the body. After reaching the tissues again the O2 is released.

Hb+O2--------> HbO2
HbO2---------> Hb+O2

ii. Transport of Co2:

So after the oxidation of glucose Co2 is released which is not required in the tissues. This Co2 is carried back by R.B.C to the lungs in the form of carb-hemoglobin. From the lungs the Co2 passes out.

2. Energy Production:

R.B.C's also play an important role in the production of energy indirectly because after carries O2 by erythrocytes to the tissues where oxidation of glucose takes places and energy is produced which is required for normal body function.

C6H12O6 + 6 O2 -----------> 6-O2 + 6+O2 = Energy

If R.B.C's left the function of O2 transport no energy will be produced because no oxidation of glucose takes place.

3. Acid-Base Balance:

They also help to maintain acid base balance. It is carried out by the buffering action for example bicarbonates and plasma protein. The buffer action of plasma protein is of great importance which carries about 10% of Co2. In lungs O2Hb is formed from reduced Hb and H+ are released react with Hco2- to give H2Co3. As inside the lungs the cone of Co2. So the equilibrium, the right and Co2 passes out.

H(+) + HCo3(-) <--------> H2Co3 <-----> H2O - Co2

Posted by: Wasim Javed

Steges of blood formation in the embryoand foatus

There are three successive stages of blood formation in the embryo and foatus.

1. Mesoblastic haemopoiesis:-

It is the blood formation and occurs in the first two months of embryonic life. In this case most of the cells are formed outside the embryo. This stage diminished in a human embryo of nine weeks.

2. Hepatic- haemopoiesis:-

This constitutes the see and stage and includes. The splenic and thy-mic blood formation this stage occurs from the end to fifth month.

3. Myeloid haemopoiesis :-

This stage beings at the fifth with the establishment of the presental circulation. In this stage first liver is responsible for the formation of R.B.C's and the bone marrow for the W.B.C's later in the bone marrow take the responsibility of fer the formation of R.B.C's


Posted by: Wasim Javed

The Need for a USB to Ethernet Adapter

The Ethernet adapter is far more reliable and much more efficient when compared to the USB while using the computer for internet surfing. Also since the connection is wireless, it makes more sense to have this adapter installed. The USB to Ethernet adapter is a modern way of integrating effectiveness with speed and provides low cost solution to desktops, laptops and notebook computers.

The main purpose is to allow for free access between machines and so for this purpose the Bridge driver needs to be installed in the CPU. In the latest machines, the driver will be automatically identified and the user will be prompted on whether or not he wishes to install the same. It is ideal to have it in the system as it allows for faster transfer of data and uninterrupted broadband services. This makes the system more reliable and perfect for environments where service needs to be uninterrupted and at a higher speed than usual. Easily available for Windows users, these might prove a bit of a hassle for those with systems running on MAC operating system. Even though the USB to Ethernet adapters are available easily at low cost, the drivers for MAC based systems are rather expensive. An alternative driver called Pegasus is available for them, which is economical and just as effective. When the USB cable is inserted it should throw up a screen that states that a new port has been added.



Posted by: Wasim Javed

What is a USB to Ethernet Adapter

While connecting an external device to the computer one makes use of the Universal Serial Bus (USB) ports available either in the front or rear side of the motherboard. Once the cable is put in place, it enables easy use of the local area network, or connection between two or more computers. Most of the external peripherals use a USB port for connection with the main computer. Since it is a plug and play system, it can be used for any kind of device as long as the related cable is put in place. The latest versions of USB supports up to 480 Mbps of data transfer which is phenomenally large when compared to the ones available earlier. In order to work faster and for the broadband connection to be fully utilized, USB to an Ethernet adapter needs to be installed. This requires special drives which first have to be put in place following which the user can enjoy unlimited internet access.


Posted by: Wasim Javed

EAP or Extensible Authentication Protocol

EAP was lately introduced as the newest PPP authentication protocol with MS CHAP V2 based features. During the authentication phase EAP is not in the picture! That's the biggest difference between EAP and other methods. EAP does not perform any sort of authentication, it in-fact only negotiates the actual EAP type and the user authentication is done by the Domain controller which hold the user database or a RADIUS (Remote Dial-in User Service) which works are an agent to get user credentials verified against a Domain Controller.

Until MS-CHAP V2, this authentication was happening only at the NAS server with the user database but with EAP, it's against a central user database holder or a Domain Controller only.

EAP is a new PPP authentication protocol that allows for an arbitrary authentication method. Once the user is connected over PPP, NAS server immediately collects the user credentials and sends them over to a RADIUS or Domain Controller for verification.


Posted by: Wasim Javed

MS-CHAP v2 or Microsoft Challenge Handshake Authentication Protocol Version 2

The newer version of MS-CHAP was introduced some after the older one giving it a name MS-CHAP V2. The encryption authentication mechanism was updated with much stronger security specifically when the username and password can now be exchanged along with determination of encryption keys. Initially the NAS server attempts to send the session ID and challenge to the remote client. The remote client uses the hash algorithm to reply back to NAS server's challenge string along with the supported encryption type, the session ID, its own peer challenge and the user password. In next step, the NAS server verifies client's information and responds with the another ID specifying the reason if this connection was a success or failure based upon the information like the negotiated encryption type, Peer challenge response, and decision on the NAS server challenge (the password client has provided).

The remote client verifies this information with the one it sent before and connects to the NAS server. If for some reason the authentication response was not correct, the remote client will terminate the connection. Therefore, it's a behavior where the both client and server authenticate each other mutually. Also, there are two type of encryption keys used, one of sending the data and the other one receiving the data.


Posted by: Wasim Javed

MS-CHAP or Microsoft Challenge-Handshake Authentication Protocol

MSCHAP is an encrypted authentication mechanism which works very similar to CHAP. We have seen in CHAP, where a NAS server sends a challenge to the client consisting of a Session ID and a hash challenge string. The remote client then, returns back the challenge with the session ID and MD4 based hashed answer. The introduction of MD4 gave an extra level of security where the clear-text was replaced with the hash passwords. MS-CHAP gave more attributes to the secure transmission of password over the wire by adding more error code aware attributes like, password expired code, next level of encryption between client and server allowing user to change there password while connected to the NAS server or during authentication process. The additional encryption between client and server is supported by using an encryption key to support data encryption by MPPE (Microsoft Point to Point Encryption).


Posted by: Wasim Javed

CHAP or Challenge-Handshake Authentication Protocol

CHAP is better than PAP as its uses encrypted authentication mechanism which would protect the username and password from being sent if the destination NAS server does not support this authentication method. Basically, the actual password will not be transmitted over the network, instead when the basic PPP connection is established, the NAS server sends a challenge phrase associated with a Session ID to the remote client. Then the remote client uses a specific MD5 (message digest version 4) hash algorithm to answer the challenge string with the username and an answer to the hash challenge with its username, network ID and password. The username will still be sent in plain text though.

CHAP is definitely a better choice than PAP where the password is sent in clear-text. But in CHAP the password is mixed up in hash form as an answer to the challenge string sent by the NAS server. Once the answer to the hash challenge is received the NAS server which already know the password, authenticates the user immediately. CHAP keeping sending challenges for the user to reply and verify its identity several times during the connection making it a more secure connection from any intrusion. The advantage CHAP carries over PAP is the way a user is authenticated over a dial-up or direct PPP connection.


Posted by: Wasim Javed