Anatomy & Physiology For Dummies
The human body is a beautiful and efficient system well worth study. In order to study and talk about anatomy and physiology, you need to be familiar with standard anatomic positions and anatomic terms, as well as the various planes, cavities, and organ systems that make up the physical form.
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.
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