For the husband is the head of the wife (οτ ανηρ εστιν κεφαλη της γυναικος). "For a husband is head of the (his) wife." No article with ανηρ or κεφαλη.

As Christ also is the head of the church (ως κα ο Χριστος κεφαλη της εκκλησιας). No article with κεφαλη, "as also Christ is head of the church." This is the comparison, but with a tremendous difference which Paul hastens to add either in an appositional clause or as a separate sentence.

Himself the saviour of the body (αυτος σωτηρ του σωματος). He means the church as the body of which Christ is head and Saviour.