CHAPTER 1: The Human Organism

CHAPTER 1 : The Human Organism

Anatomy is the scientific discipline that investigates the structure of the body. Anatomy means to dissect, or to cut apart and separate

Two basic approaches to study of anatomy

Systemic anatomy is the study of the body by system.

Regional anatomy is the study of the organization of the body by areas.

Structural and Functional Organization

Chemical  level

 It involves interaction between atoms, which are the tiny building blocks of matter. Atoms are combined to form molecules, such as water, sugar, fats, proteins, and deoxyribose nucleic acid.

Cell level

Cells are the basic structural and functional unit of organism. Molecules are combined to form organelles

Tissue level

A tissue is a group of similar cells and the materials surrounding them.

  Organ level

 Is a combination of two or more tissue to form a certain function. Examples of organs are urinary bladder, skin, stomach, and eye.

Organ system level

Is a group of organs classified as a unit because of its common function. For example, the urinary system

Organism level

Is any living thing considered as a whole.

Homeostasis

Homeostasis is the existence and maintenance of a relatively constant environment within the body

Terminology and the Body Plan

Studying terms is easier when we will first study the origin of the term. For example foramen means a hole and magnum means large. Foramen magnum is therefore I a large hole in the skull.

Body Position

Anatomical position refers to a person standing erect with the face standing directed forward. Position of the body may affect the description of the body parts to each other. A person is supine when lying face upward and prone when lying face downward.

Directional Terms

Directional terms describe part of the body relative to each other. Up is replaced by superior, down by inferior. Proximal means nearest, Distal means more distant.

In anatomical terminology, front is replaced by anterior, back by posterior

Body Parts and Regions

The arm extends from the shoulder to the elbow, and the forearm extends from the elbow to the wrist.

The abdomen is often subdivided into four quadrants. In addition to this quadrant, the abdomen is sometimes subdivided by regions

Planes

A Sagittal plane runs vertically through the body separating it into left and right part. The the median plane is a sagittal plane that passes through the median of the body. A transverse  or  horizontal  plane  runs parallel to the surface of the body.

Body Cavities

The rib cage is surrounded by thoracic cavity.  The abdominal muscles primarily enclose the abdominal cavity, which contains the stomach, intestines, liver, spleen, pancreas, and kidneys.  Pelvic bones encase the small space for  pelvic cavity.

Serous membranes

Serous membranes covers the organ of the trunk cavities and line the trunk cavities.