Anatomy

Embryology

is the study of these early developmental processes.

Histology

takes a broader perspective and examines tissues, groups of specialized cells and cell products that work together to perform specific functions.

Movement

Organisms are capable of producing movement, which may be internal (transporting food, blood, or other materials inside the body) or external (moving through the environment).

Metabolism and Excretion

Organisms rely on complex chemical reactions to provide energy for responsiveness, growth, reproduction, and movement. They must also synthesize complex chemicals, such as proteins. The term metabolism refers to all the chemical operations under way in the body: Catabolism is the breakdown of complex molecules into simple ones, and anabolism is the synthesis of complex molecules from simple ones. Normal metabolic operations require the absorption of materials from the environment. To generate energy efficiently, most cells require various nutrients, as well as oxygen, an atmospheric gas. The term respiration refers to the absorption, transport, and use of oxygen by cells. Metabolic operations often generate unneeded or potentially harmful waste products that must be removed through the process of excretion.

Reproduction

Organisms reproduce, creating subsequent generations of their own kind, whether unicellular or multicellular.

Responsiveness

Organisms respond to changes in their immediate environment; this property is also called irritability. You move your hand away from a hot stove; your dog barks at approaching strangers; fish are scared by loud noises; and amoebas glide toward potential prey. Organisms also make longer-lasting changes as they adjust to their environments. For example, as winter approaches, an animal may grow a heavier coat or migrate to a warmer climate. The capacity to make such adjustments is termed adaptability.

Growth and Differentiation

Over a lifetime, organisms grow larger, increasing in size through an increase in the size or number of their cells. In multicellular organisms, the individual cells become specialized to perform particular functions. This specialization is called differentiation. Growth and differentiation in cells and organisms often produce changes in form and function. For example, the anatomical proportions and physiological capabilities of an adult human are quite different from those of an infant.

Organs

Tissues in combination form organs such as the heart, kidney, liver, and brain. Organs are anatomical units that have multiple functions.

Cytology

analyzes the internal structure of cells, the smallest units of life. Living cells are composed of complex chemicals in various combinations, and our lives depend on the chemical processes occurring in the trillions of cells that form our body.

Regional anatomy

considers all of the superficial and internal features in a specific area of the body, such as the head, neck, or trunk.

Microscopic anatomy:

considers structures that cannot be seen without magnification. The boundaries of microscopic anatomy, or fine anatomy, are established by the limits of the equipment used.

Comparative anatomy

considers the anatomical organization of different types of animals. Observed similarities may reflect evolutionary relationships. Humans, lizards, and sharks are all called vertebrates because they share a combination of anatomical features that is not found in any other group of animals.

Systemic anatomy

considers the structure of major organ systems, such as the skeletal or muscular systems. Organ systems are groups of organs that function together to produce coordinated effects. For example, the heart, blood, and blood vessels form the cardiovascular system, which distributes oxygen and nutrients throughout the body. There are 11 organ systems in the human body, and they will be introduced later in the chapter. Introductory texts in anatomy, including this one, use a systemic approach because it provides a framework for organizing information about important structural and functional patterns.

Developmental anatomy

examines the changes in form that occur during the period between conception and physical maturity. Because it considers anatomical structures over such a broad range of sizes (from a single cell to an adult human), developmental anatomy involves the study of both microscopic and gross anatomy.

Clinical anatomy

focuses on anatomical features that may undergo recognizable pathological changes during illness.

Cross-sectional anatomy

has emerged as a new subspecialty of gross anatomy as newadvances in radiographic anatomy, suchasCT(computerized tomography) and spiral scans, have emerged.

Radiographic anatomy

involves the study of anatomical structures as they are visualized by x-rays, ultrasound scans, or other specialized procedures performed on an intact body.

Gross anatomy

or macroscopic anatomy, considers relatively large structures and features visible to the unaided eye. There are many ways to approach gross anatomy: ● Surface anatomy refers to the study of general form, or morphology, and superficial anatomical markings. ● Regional anatomy considers all of the superficial and internal features in a specific area of the body, such as the head, neck, or trunk. ● Systemic anatomy considers the structure of major organ systems, such as the skeletal or muscular systems. Organ systems are groups of organs that function together to produce coordinated effects. For example, the heart, blood, and blood vessels form the cardiovascular system, which distributes oxygen and nutrients throughout the body. There are 11 organ systems in the human body, and they will be introduced later in the chapter. Introductory texts in anatomy, including this one, use a systemic approach because it provides a framework for organizing information about important structural and functional patterns.

Surface anatomy

refers to the study of general form, or morphology, and superficial anatomical markings.

Surgical anatomy

studies anatomical landmarks important for surgical procedures.