How to install drivers?

Question

On Windows you go to the Device manager, right click the device, click Update driver and follow through the prompts.
How does one do this on a Mac?

Answer 1

USB terminology is confusing because it is highly abstracted & hierarchical. Some of it refers to hardware, some to software, & some to parts of both. For instance +interface standards+ like OHCI, UHCI, & EHCI each define the requirements for both a conformal Host Controller (a hardware device) and a Host Controller driver (software) to operate a Universal Serial Bus (an abstract collection of devices including both the software and hardware that allow connections between them). These devices can be logical or physical entities & each have one or more capabilities.
However, both the hardware & software implementations of these standards can & do differ greatly. For example, UHCI is a proprietary standard providing full and low speed USB functionality for Intel chipsets; OHCI is a corresponding open standard for pretty much those of every other manufacturer. EHCI is a public standard for USB high speed (2.0) functionality.
These standards also require that a +root hub+ be attached directly to the Host Controller, but not how many ports (points of connection for access to or from the system) it must have. Root hub ports may connect hosts to hubs or directly to other downstream devices, internal or external. Moreover, there may be more than one Host Controller in the system.
I realize all this may be confusing but the point is you can't really separate the hardware from the software if you want to understand how it all works, nor can you generalize beyond a very superficial level from one system to another. Thus the earlier comment (not my own) that it doesn't work like you think it does.
How it does work is that all of the necessary Host Controller driver software is installed in /System/Library/Extensions/IOUSBFamily.kext/Contents/PlugIns (including AppleUSBEHCI.kext, AppleUSBUHCI.kext, & AppleUSBOHCI.kext) if the OS is installed on the startup drive. I don't know what you mean by "when you install from a USB drive" but the bus type or its speed has nothing to do with this process. If you installed the OS correctly then this software was installed, period. The OS installer doesn't install different driver software on or for different hubs, busses, or interfaces depending on which of them is in use at install time -- it is all or nothing, & if it is nothing then the installed OS can't access anything over USB at any speed. Period, end of story.
So something is causing your problem, but not what your theory suggests. To help you figure out what that is, we need to know what you mean about installing from a USB drive vs. the internal one. I suspect by "installing" you really mean "starting up from." If you mean something else, please explain in detail what you mean by that.
BTW, as you might expect from the above, System Profiler provides an abstracted, hierarchical OS level view of the USB hardware called the +USB Device Tree+. At the first level you see the USB busses. Each is associated with a bus number, a Host Controller location & its root hub (usually built-in), the interface driver (OHCI, UHCI, or EHCI) it uses, & its other OS level characteristics. But remember that a bus is a collection of devices & that a device may be a logical (virtual) or physical (real) entity. Because of this, trying to interpret this view as a strictly hardware representation will only confuse you. (That is what JaimieV meant about ignoring the virtual structure.) IOW, it isn't directly analogous to a hardware block diagram or to the actual hardware connections in your Mac.
In fact, USB allows devices conforming to different interface standards to operate over the same physical connections (something else I think you are at least a little confused about). In System Profiler this is represented by different downstream devices appearing in the hierarchy of different (virtual) USB busses, each with its own instance of OS level characteristics including a bus number & host driver location.
I don't know what devices you are seeing appear where in this virtual hierarchy -- different Macs use different internal hub implementations & I don't have an MBP -- but I believe you should see at least two "USB High-Speed Bus" & up to about 5 "USB Bus" entries in the first level bus entries. The first type corresponds to the EHCI host implementation & the second should be for the UHCI one. Hubs & other devices downstream of the host should appear in their second & subsequent hierarchic levels. I don't think any internal downstream device should appear under a first level "USB Bus" entry with a OHCI host controller characteristic (except possibly the card reader), but every high speed (USB 2.0) device should be under a "USB High-Speed Bus" entry. Note that the "Speed" characteristic of the device has nothing to do with the bus speed -- it is entirely possible a low speed device is on a high speed EHCI compliant bus & shares its bandwidth with high speed devices on the same bus.
If this doesn't sound like what System Profiler is showing you, please explain in detail what it does show. But please remember that this is a virtual representation, not a literal hardware one.