Table 1.

Cells (as a percentage of epithelial cells) in the airways of healthy humans.

Cell Type	Bronchi	Larger Bronchioles	Smaller Bronchioles	Reference
Basal	27–30	27–30	4–23	Crystal 2014 [16] Boers 1998 [13] Walters 2014 [44]
		8 → 50	2–22	Okuda 2021 [15] Zuo 2020 [45] Deprez 2020 [20] Braga 2019 [18] Travaglini 2020 [17]
Ciliated	53	62–71		Staudt 2014 [46] Walters 2014 [44]
		5 → 50	30–60	Okuda 2021 [47] Zuo 2020 [45] Deprez 2020 [20] Braga 2019 [18] Travaglini 2020 [17] Paranjapye 2022 [48]
Goblet	11	1–10	0–2	Lumsden 1984 [14] Boers 1999 [15]
Club Cell (“Secretory Cell”)	0	1–30	10–40	Lumsden 1984 [14] Boers 1999 [15] Okuda 2021 [47] Zuo 2020 [45] Deprez 2020 [20] Braga 2019 [18] Travaglini 2020 [17] Paranjapye 2022 [48]
Neuroendocrine	“rare” (0.2–0.5)			Boers 1996 [34] Knight 2003 [33]
	“abundant” (2.5–10)			Weichselbaum 2005 [35]
Ionocytes	“rare” (<1–2)			Plasschaert 2018 [43] Braga 2019 [18] Scudieri 2020 [24] Travaglini 2020 [17] Paranjapye 2022 [48]
Tuft Cell (Brush Cell)	“rare”			Goldfarbmuren 2020 [49] Ualiyeva 2020 [31] Deprez 2020 [20]