Integrated graphics is a GPU that is built into the motherboard or the CPU this means no add in card is used. These are most common in laptops and low cost computers as they are basically free with the Processor but cannot be upgraded unless you swap the processor for a higher version.
Converts image information into electrical currents that vary to display an image on the computer monitor.
Two major companies in the design of the cards are Nvidia and ATI, although there are many others. The cards may not exist in some cases, where a computer might use on-board video card's on the chipset (such as those made by Intel).
Nvidia and ATI don't make the cards themselves, instead they develop the Graphical Processing Units (GPUs). These are taken by other companies and developed into the cards, with varying levels of Graphical RAM and output ports.
Nvidia's double-card technology is named SLi, ATI's is named CrossFire.
Historically, the cards slotted into AGP slots, these were updated by PCI and later to todays standard, PCI-E (which is in 4x and 16x most commonly) and has updated versions from 1.0 to 3.0. The different slots allow increasingly more bandwidth to travel through them to the motherboard.
The GPU is a part of the graphics card which stands for GRAPHICS PROCESSING UNIT, a lot of people mistake the GPU for the actual card itself. This is the brains of the card which does all the visual processing.
Ram or Random Access Memory is much the same on a graphics card as it is on a motherboard it is a dedicated graphics memory, so it is separate and not used by any other part of your PC.
Most Modern Graphics card's memory can range from 512MB all the way up to 11GB with the most popular types of memory being DDR3 or GDDR5.
Memory is quite important if you want to play games or render videos at higher resolutions or higher quality textures as this stores all the graphical information that needs to be displayed on the screen.