This particular home has block walls that are built with a mixture of 8x8x16 (full blocks), 8x8x8 (half blocks), pre-stressed lintels above doors and windows, and your top course that we call a Bond Beam block, seen below.
The bond beam block runs the entire top section of the block wall so that it can be poured solid. Rebar is run in the middle of the bond beam block to tie in the rebar that is placed inside the walls. The below plan shows you where each solid downpour is located. In the exterior wall you will see solid black squares that represents each downpour.
The simple drawing below shows how the rebar is run through the top bond beam and inside the block walls.
Below you will see an open block with rebar inside. These are inspections ports so the city/county inspector can ensure everything is tied together properly before the down pours are filled.
Once the inspector passes the bond beam inspection all of the ports will be covered with plywood so the cells can be filled.
Going back to one of our first posts you will see the footers being poured for our stem wall. The footers have rebar that stick out vertically (seen in the picture below). This is how the footers, slab, block walls, and bond beam are all tied together with concrete.
So, how do you know the cells fill all the way up? Do the inspectors some back and check the wall after the concrete is added?