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.
Federal Motor Vehicle Safety Standard No. 121 mandates antilock braking systems (ABS) on all new air-. braked vehicles with a GVWR of 10,000 pounds or greater. ABS is required on tractors manufactured on. or after March 1, 1997, and air-braked semi-trailers and single-unit trucks manufactured on or after March. 1, 1998.