3 Mixed seromucous salivary glands, structure of glandular acini The three large glands have a different composition in the type of secretory units is concerned: - The parotid glands (which represent 25% of the production of saliva) are formed by serous production units and they are compound acinar type.
How Anti-Lock Brakes Work. An anti-lock brake system (ABS) is a braking system that is made to allow a vehicle to maintain traction with the road when braking. Braking is controlled by driver input via the brake pedal, and older braking systems response to a driver braking suddenly or with intense pressure was sometimes to lock up or skid.
What Is a Brake Booster? Brake boosters are used only on power brakes, not manual brakes. The booster's function is to give more braking power with minimal pressure on the brake pedal. If the booster is not working properly, you will still have brakes, but the brake pedal will be very hard to push. A brake booster is what gives power brakes their power. It works on vacuum from the engine. The booster pushes on the master cylinder with the pressure applied to the booster by stepping on the brake. If the engine is off, it cannot get vacuum, therefore the brakes will be hard when the engine is off.