Will you, or someone you know, be a patient (sick person) in a hospital? Be sure you know what jobs people in a hospital are expected to do. It is not a nurse's job to bring you a glass of water, even if they do so to be kind.
A nurse is a highly trained health care professional. A clerk in a doctor's office is not a nurse. In a hospital the person most responsible for your recovery is your nurse. The doctor is an academic who provides advice to the nurse, then moves on to the next patient. The nurse takes care of you and tells the doctor if there is any change in your condition. Most medical work done with a patient is done by nurses. Other people work for the nurse. I recommend asking the orderly (medical assistant) for a glass of water or to clean up a mess.
Not all nurses are women and not all doctors are men. Male nurses are needed for male wards and there are not enough male nurses. So for young men looking for a job, consider training to be a nurse. If you do want to become a nurse, take a course that leads to an RN (Registered Nurse) certification. There are other easier health care courses, for orderlies.
The Accident and Emergency ward is for what it says. They take care of people who need serious medical help quickly. Anyone with a mild cold or headache can go and buy the appropriate medicine in a store. Otherwise they will wait for a very long time. An ambulance is for bringing someone to the hospital who is so sick that they could not take a taxi.1
A surgeon is an elite doctor with special training. Surgeons, not ordinary doctors, cut people open to fix problems. In British English, surgeons (at least male ones) use the title Mr to show that they are different from mere doctors. (Common Titles - Mr Surgeon)
A pharmacist has specialist training in chemistry; that is why they are called a chemist in British English. To be confusing the word chemist can also refer to a non-medical chemical worker. A pharmacist must understand medicines and explain how they are taken, side effects and interactions with other drugs. A pharmacist should know if a medicine needs to be stored in the refrigerator or not. They can tell you if it should be taken with food or if some foods should be avoided with the medicine. If needed, they can also prepare medicines from chemical stocks. A dispenser can read the label, count out the correct number of pills and give them to you. If you have a question, ask the pharmacist, not just anyone behind a counter.
Try to make sure that you know who is who and what they do. Don't call an ambulance for a normal headache. Ask a pharmacist questions, not a dispenser. Your doctor might be a woman and your nurse a man.
1. There are of course non-emergency ambulances or patient transport ambulances which are vans or minibuses painted in hospital colours for transporting regular or long term (chronic) patients to and from treatment.