Thoracic diaphragm

In human anatomy, the thoracic diaphragm, or simply the diaphragm (Ancient Greek: διάφραγμα diáphragma "partition"), is a sheet of internal skeletal muscle that extends across the bottom of the thoracic cavity. The diaphragm separates the thoracic cavity containing the heart and lungs, from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.

The term "diaphragm" in anatomy can refer to other flat structures such as the urogenital diaphragm or pelvic diaphragm, but "the diaphragm" generally refers to the thoracic diaphragm. In humans, the diaphragm is slightly asymmetric -- its right half is higher up (superior) to the left half, since the large liver rests beneath the right half of the diaphragm.

Other mammals have diaphragms, and other vertebrates such as amphibians and reptiles have diaphragm-like structures, but important details of the anatomy vary, such as the position of lungs in the abdominal cavity.

Diaphragm

Diaphragm (Ancient Greek: διάφραγμα diáphragma "partition") may refer to any of the following:

Acoustics

Anatomical structure

Optics and photography

Other

Anatomy

Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts. In some of its facets, anatomy is related to embryology and comparative anatomy, which itself is closely related to evolutionary biology and phylogeny.Human anatomy is one of the basic essential sciences of medicine.

The discipline of anatomy is divided into macroscopic and microscopic anatomy. Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch of superficial anatomy. Microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology, and also in the study of cells.

The history of anatomy is characterized by a progressive understanding of the functions of the organs and structures of the human body. Methods have also improved dramatically, advancing from the examination of animals by dissection of carcasses and cadavers (corpses) to 20th century medical imaging techniques including X-ray, ultrasound, and magnetic resonance imaging.

USMLE Step 1

The USMLE Step 1 (more commonly just Step 1 or colloquially, The Boards) is the first part of the United States Medical Licensing Examination. It assesses whether medical school students or graduates can apply important concepts of the sciences fundamental to the practice of medicine. US medical students, as well as Canadian medical students who wish to seek licensure in the US, typically take Step 1 at the end of the second year of medical school. Graduates of international medical schools (i.e., those outside the US or Canada) must also take Step 1 if they want to practice in the US. Graduates from international medical schools must apply through ECFMG, and the registration fee is $850. For 2015, the NBME registration fee for the test is $590, with additional charges for applicants who choose a testing region outside the United States or Canada.

Format

The exam is an eight-hour computer-based test taken in a single-day, composed of seven 44-question sections with a total of 308 multiple-choice questions. One hour is provided for each section, allotting an average of a minute and eighteen seconds to answer each question. Between test sections, the test taker is allotted a cumulative 45 minutes (during the test day) for personal breaks. (There is a 15-minute tutorial at the beginning of the exam, which the test-taker can choose to skip and have that time added to break time.) If the taker finishes any section before the allotted one hour time limit, the unused time is added to the break time total. The test is administered at any of several Prometric computer testing sites.

Human body

The human body is the entire structure of a human being and comprises a head, neck, trunk (which includes the thorax and abdomen), arms and hands, legs and feet. Every part of the body is composed of various types of cells, the fundamental unit of life.

At maturity, the estimated average number of cells in the body is given as 37.2 trillion. This number is stated to be of partial data and to be used as a starting point for further calculations. The number given is arrived at by totalling the cell numbers of all the organs of the body and cell types. The composition of the human body is made up of a number of certain elements including carbon, calcium and phosphorus.

The study of the human body involves anatomy and physiology. The human body can show anatomical non-pathological anomalies known as variations which need to be able to be recognised. Physiology focuses on the systems and their organs of the human body and their functions. Many systems and mechanisms interact in order to maintain homeostasis.