As a singer your body is part of your instrument and your voice is produced through many complex steps which are the power source, the vibrators(or oscillators), and the shapers(resonators & articulators).
Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762
Each part is intertwined and connected to other parts of the body to make it work as one organization, and therefore if one part is broken or doesn't work properly then that small part is going to affect the whole body.
Have you had a tooth ache before ? Because of that small part of the body is in poor condition, the whole body will be affected by it and won't be able to function as it was in a normal condition.
For example it is very possible that your voice can be affected by sprained wrist or ankle or any other injuries in joints because even a small injury can misaligned the body posture and it can weaken and malfunction your voice.
The first place where the voice production starts is your brain.
As you decide to speak or sing, your brain sends signals to the nerves and the muscles. And then the brain feels and hears the outcome and makes a required adjustment to produce the sound you intend to make.
After that lungs, abdomen including diaphragm, chest and back muscles create air flow in a high pressure.
And then air goes through the vocal folds(the vocal cords) in the larynx(the voice box) that vibrate at different frequencies.
Voice is created when the vocal folds open and close like hand clapping.
The stronger the vocal folds shut, the louder the voice becomes, the more often they open and close, the higher the voice becomes and the frequency of the sound becomes higher.
After that the quality of your voice is shaped by the shapers that are the resonators(amplifiers: Chest, Tracheal Tree, Pharynx, Larynx, Oral Cavity, Nasal Cavity, Sinuses) and the articulators(modifiers: Lips, Tongue, Teeth, Soft & Hard Palates, Cheeks).
Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762.
The tongue positions, the raised and lowered larynx and the soft palate changes the original tone from the vocal folds significantly.
Then see you in the next blog 'The Diaphragmatic Breathing For Singing', Hun~
Keep learning & keep Singing!