Which description fits the macula densa?

1. The initial part of the distal convoluted tubule loops back to touch the arterioles of its own glomerulus. 2. The wall of the tubule at that point of contact is the macula densa. 3. It is a cluster of cuboidal epithelial cells that monitors the composition of fluid flowing through the tubule. 4. It responds to the sodium concentration in that fluid by releasing paracrine signals. 5. Each cell also carries a single nonmotile cilium that reports the rate of fluid movement. 6. Renin secretion belongs to the juxtaglomerular cells of the afferent arteriole, which the macula densa regulates rather than replaces. 7. Filtration slits are formed by podocyte pedicels at the capillary surface, a different structure altogether. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 25 "The Urinary System", section 25.4 Microscopic Anatomy of the Kidney_