Medical Terminology: Lesson 1 — Chapter 2 (Human Body)

Anatomical Reference Systems

A set of standard terms used to describe the positions, directions, and parts of the human body, facilitating clear communication in medical and anatomical contexts.

Body Planes

Divisions of the body used to describe anatomical locations and movements, including sagittal, frontal, and transverse planes.

Vertical Planes

Planes that divide the body into left and right sections, allowing for descriptions of movement and location in relation to the midline.

Sagittal Plane

Divides the body into unequal left and right portions

Midsagittal plane

Divides the body into equal left and right portions

Coronal/Frontal Plane

Divides the body into anterior (front) and posterior (back) portions

Ventral

Front or belly side of the organ or body

Anterior

Situated in the front or forward part of an organ

Dorsal

Back off the organ or body

Posterior

Situated in the back or back part of an organ

Cephalic

Toward the head

Caudal

Toward the lower part of the body

Proximal

Situation nearest the midline or beginning of a body structure

Distal

Situation farthest from the midline or beginning of a body

Medial

Direction toward, or nearer, the midline

Lateral

Direction toward, or nearer, the side of the body, away from the midline.

Major Body Cavities

Spaces within the body that contain and protect internal organs. The two major body cavities are the Dorsal (back) cavity and Ventral (front)

Dorsal Cavity

Contains organs of the nervous system that coordinate body functions. Consists off the cranial cavity, located within the skull and protects the brain, and the spinal cavity, located within the spinal column and protects the spinal cord.

Ventral Cavity

contains the organs that sustain homeostasis, divided into the following portsions:

• Thoractic Cavity/;chest cavity/thorax

• Abdominal Cavity

  • Pelvic Cavity

Thoractic Cavity

Surrounds and protects the heart and lungs

Abdominal Cavity

Contains major organs of digestion

Pelvic cavity

Space formed by the hip bones and contains the organs of the reproductive and excretory systems

9 Parts of the Regions of the Thorax and Abdomen

• The Right and Left Hypochondriac Regions (below the ribs)

• Epigastric Region (above stomach)

• Right and Left Lumbar Regions (near the inward curve of the spine)

• Umbilical Region (surrounds the umbilicus, commonly known as belly button or naval)

• Right and Left Iliac Regions (near the hip bones)

• Hypogastric Region (below the stomach)

Quadrants of the Abdomen

Right Upper Quadrant (RUQ)

Left Upper Quadrant (LUQ)

Right Lower Quadrant (RLQ))

Left Lower Quadrant (LLQ)

Peritoneum

Multilayered membrane that protects and hols the organs in place within the abdominal cavity

Parietal Peritoneum

Outer layer of the peritoneum that lines the interior of the abdominal wall

Mesentery

A fused double layer of the parietal peritoneum that attaches parts of the intestine to the interior abdominal wall

Visceral Peritoneum

Inner layer off the peritoneum that surrounds the organs of the abdominal cavity

Retroperitoneal

Means located behind the peritoneum

Peritonitis

Inflammation of the peritoneum

Cells

Basic structural and functional units of the body. They are specialized and grouped together to form tissues and organs

Cell Membrane

The tissue that surrounds and protects the contents of a cell

Cytoplasm

The material within the cell membrane that is not part of the nucleus

Nuclues

Structure within a cell. Controls the activities of a cell and helps it divide

Stem Cells

Unspecialized cells that are able to renew themselves for long periods of time by cell division.

But under certain conditions, stem cells can be transformed into cells with special functions.

Adult Stem Cells/Somatic Stem Cells

Undifferentiated cells found among differentiated cells in a tissue or organ. Primary role is to maintain and repair the tissue in which they are found

Embryonic Stem Cells

Undifferentiated cells that are unlike any specific adult cells. Primarily role is to form any adult cell. These cells and proliferate (grow rapidly) indefinitely in a lab and could therefore potentially provide a source or adult muscle, liver, bone, or blood cells.

Genetics

A fundamental physical and functional unit of heredity. Controls hereditary diseases and all physical traits.

Genome

The complete set of genetic information of an organism

Chromosome

A genetic structure located within the nucleus off each cell. These chromosomes are made up of DNA molecules containing the body’s gene. The chromosomes helps a cell keep the genetic information neat and organized.

Somatic Cells

Any cell in the body except the gametes (sex cells).

Contains 46 chromosomes arranged into 23 pairs.

Gamete/Sex Cell

The only cell that does not contain 46 chromosome. Each ovum (egg) or sperm has 23 single chromosomes. When they join, the fetus then haas 46.

DNA

Deoxyribonucleic Acid. Provides information essential for heredity, determining physical appearance, disease rates, and other traits.

The main components off chromosomes. Found in the nucleus of all types o cells except erythrocytes (do not have a nucleus)

Genetic Mutation

Change of the sequence of a DNA molecule

Somatic Cell Mutation

Change within the cells of the body and cannot be transmitted to the next generation

Gametic Cell Mutation

Change within the genes in a gamete that can be transmitted by a parent to their children

Genetic Disorders

A pathological condition caused by an absent or defective gene. May be at birth, or manifest later on.

Tissues

A group or layer of similarly specialized cells that join together to perform certain specific functions. The 4 main tissues consist of Epithelial tissue, Connective tissue, Muscle tissue, and Nerve tissue.

Epithelial Tissue

Specialized epithelial tissue that forms the epidermis of the skin and the surface layer of mucous membranes

Endothelium

The specialized epithelial tissue that lines the blood and lymph vessels, body cavities, glands, and organs.

Connective Tissues

Supports and connects organs and other body tissues.

Adipose Tissue

Also known as fat, provides protective padding, insulation, and support.

Muscle Tissue

Contains cells with the same specialized ability to contract and relax

Nerve Tissue

Contains cells with the specialized ability to react to stimuli to conduct electrical impulses

Aplasia

The defective development, or the congenital absence, of an organ or tissue.

Hypoplasia

The underdevelopment of an organ or tissue, usually due to a deficiency in the number of cells.

Anaplasia

A change in the structure of cells and in their orientation to each other, a characteristic of most cancerous tumor formation.

Dysplasia

The abnormal development or growth of cells, or the presence of abnormal cells

Hyperplasia

An increase in the number of cells in a tissue or organ

Hypertrophy

A general increase in the bulk of a body party or organ that is due to an increase in the size, but not in the number, of cells in the tissues.

Gland

A gland is a group of specialized epithelial cells that are capable of producing secretions

*secretions are the substances produced by a gland.

Exocrine Glands

Secrete chemical substances into ducts that lead either o other organs our out of the body

Endocrine Glands

Produces hormones, therefore do not have ducts. These hormones are secreted directly into the bloodstream and are then transported to organs and structures throughout the body

Aden/o

Gland

Adenoids

A mass of gland-like lymphoid tissue at the back o the upper pharynx.

Adenocarcinoma

A malignant tumor that originates in the glands and may spread to other parts of the body.

Adenoma

A benign tumor that starts in the epithelial tissue of a gland or gland-like structure

*Benign means not life threatening

Adenosis

Any disease or condition of a gland