Mmm... While neither anatomy nor physiology,
Movement is the go-to book for FMS, and in my opinion every movement professional should read it.
Becoming a Supple Leopard is another book I recommend.
In my instructor course (the government supervised gym instructor course in Israel) we had our own course booklet, but as
@Anna C said, any academic introduction level book would do. IMHO for basic anatomy and physiology Wikipedia would also deliver if you know what to look for, specially since you just need some refreshing to do.
From my experience the stuff we need regarding these as quality strength teachers are the basics. The "real" needs in physiology, neuro-physiology, cognition and whatever scientific terms we want, are covered in
Movement for FMS. While never attending (yet) SFG, I am 100% sure that all the relevant needs are addressed in the certification.
Trust SFG and FMS staff that they will provide you with the tools and knowledge.
I'll start a rant now...
I know far too many trainees and coaches that know anatomy and physiology at a high level and have zero grasp on human movement or how to teach it. This pretty much is aided by the teaching of classical kinesiology, along with the (un)functional anatomy it is based on and has no actual roots in reality. Try to analyze a squat or a deadlift, or any other compound movement, and you'll see massive internal contradictions. I think this is where to foundations of body-part Frankenstein training lay.
I prefer a coach who might not know all the names and origin and insertion points of the muscle in the rotator cuff and scapula, but teach how pack the shoulder when you press than the more common coach, who knows anatomy perfectly, but don't know what shoulder packing is and why you need to do it. The chief instructor in my course told me that improving my shoulder stability and technique work will not increase my bench press at all... Well, it did...
Rant over