Anatomy & Physiology For Dummies

Describing the Anatomic Position

To describe or talk about human anatomy, you need to start from an agreed-upon view of the human body. The anatomic position for the human form is the figure standing upright, eyes looking forward, upper extremities at the sides of the body with palms turned out.

Anatomic Terms

When you’re talking anatomy in a scientific way, everyday words such as front, back, side, above, and below just aren’t precise enough. Instead you use the anatomic terms in the following list:

• Anterior or ventral: Toward the front of the body

• Posterior or dorsal: Toward the back of the body

• Cranial: Head end of body

• Caudal: Tail end of body

• Superior: A part above another part

• Inferior: A part below another part

• Medial: Toward the midline (median plane) of the body

• Lateral: Away from the midline of the body; toward the sides

• Proximal: Toward the point of attachment to the body

• Distal: Away from the point of attachment to the body

• Internal: Toward the inside of the body

• External: Toward the outside of the body

• Parietal: A membrane that covers an internal body wall

• Visceral: A membrane that covers an organ

Anatomical Planes of the Body

You may not think about the planes of your body much, but you have them nonetheless, and if you’re talking anatomy, knowing the names of the planes comes in handy. (Too bad sagittal and tranverse don’t lend themselves to song as easily as rain and Spain do.) The main planes and their subplanes are in the following list:

• Sagittal: Plane that runs down through the body, dividing the body into left and right portions. Subsections of the sagittal plane include:

  • Midsagittal runs through the median plane and divides along the line of symmetry

  • Parasagittal is parallel to midline but does not divide into equal left and right portions.

• Coronal (frontal): Plane that runs perpendicular to the sagittal plane and divides the body into anterior and posterior (front and back) portions.

• Transverse: Horizontal plane that divides the body into upper and lower portions; also called cross-section.

Anatomical Body Cavities

Medical shows and crime shows have made body cavities all too familiar, and anatomically speaking, these spaces are very important, providing housing and protection for vital organs. The following list identifies the cavities and subcavities of the human body:

• Dorsal cavity: Bones of the cranial portion of the skull and vertebral column, toward the dorsal (posterior) side of the body.

  • Cranial cavity: Contains the brain

  • Spinal portion: Contains the spinal cord, which is an extension of the brain

• Ventral cavity: Anterior surface of torso; divided by diaphragm muscle into upper thoracic cavity and abdominopelvic cavity.

• Thoracic cavity: The chest; contains trachea, bronchi, lungs, esophagus, heart and great blood vessels, thymus gland, lymph nodes, and nerves. Contains smaller cavities, too:

  • Pleural cavities surround each lung

  • Pericardial cavity contains the heart. The pleural cavity surrounds both the pleural and pericardial cavities.

• Abdominopelvic cavity: Imaginary line that runs across hipbones divides the body into the abdominal and pelvic cavities.

  • Abdominal cavity: Contains stomach, liver, gallbladder, pancreas, spleen, kidneys, and intestines (small and large), ovaries (in female); the peritoneal cavity (peritoneum) surrounds the abdominal organs

  • Pelvic cavity: Contains colon, rectum, urinary bladder, uterus (in females)

Anatomic Organ Systems

If you’re talking anatomy and physiology, you’re talking about the human body and its organs. The 11 systems in the following list provide the means for every human activity from breathing to eating to moving to reproducing:

• Skeletal: Bones and connective tissues

• Muscular: Striated skeletal muscle

• Integumentary: Skin, nails, hair, glands in skin, nerve endings, and receptors in skin

• Nervous: Brain, spinal cord, ganglia, nerves, sensory organs

• Circulatory: Heart, blood vessels, blood

• Lymphatic: Tonsils, spleen, thymus, lymph nodes, lymphatic vessels, and lymph fluid

• Digestive: Mouth, esophagus, stomach, small and large intestine (all in gastrointestinal tract); accessory (or associated) organs include salivary glands, pancreas, liver, and gallbladder

• Respiratory: Nose, pharynx, larynx, trachea, bronchi, and lungs

• Urinary: Kidneys, ureters, bladder, and urethra

• Endocrine: Pituitary, thyroid, parathyroid, adrenals glands, endocrine portion of pancreas, ovaries, and testes (all secrete hormones into blood)

• Reproductive: Ovaries, uterine tubes, uterus, vagina, and vulva in females; testes, seminal vesicles, penis, urethra, prostate, and bulbourethral glands in males