Anatomy and Physiology For Dummies

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If you’ve taken geometry, you know that a plane is a flat surface and that a straight line can run between two points on that flat surface. Geometric planes can be positioned at any angle. In anatomy, usually three planes separate the body into sections. Figure 1-2 shows you what each plane looks like. The reason for separating the body with imaginary lines — or by making actual cuts referred to as sections — is so that you know which half or portion of the body or organ is being discussed. The anatomical planes are as follows: Variety Sapiens: Some species get a varietal name, usually indicating a difference that’s obvious but not necessarily important from an evolutionary point of view. The human species has one other variety, Homo sapiens neanderthalensis, which has been extinct for tens of thousands of years. All humans living since then are of one species variety, Homo sapiens sapiens. In the evolutionary classification of humans, there’s no biologically valid category below species variety. A Little Chat about Jargon Closely associated with the skeletal system is the muscular system, which consists of the muscles and associated tendons. The latter are fibrous bands of connective tissue that attach striated (skeletal) muscles to bone. The primary task of the muscular system is to aid in movement. Muscles also play a role in thermoregulation: muscle contractions produce heat, which helps maintain a constant body temperature, which aids in homeostasis. Thoracic cavity:The chest or thorax; contains the heart, lungs, and their associated structures, as well as the esophagus and several glands

If you’re talking anatomy and physiology, you’re talking about the human body and its organs. The 11 systems in the following table provide the means for every human activity — from breathing to eating to moving to reproducing: System Figure 1-4: Levels of organization in the human body. 9780470923269-fg0104.eps Level I: The cellular level The body takes a divide-and-conquer approach to completing all of the tasks it must do to sustain life. Each body system has its own role to play, as shown in the table below. System Species Sapiens: All species are given a two-part Latin name, in which the genus name comes first and a species epithet comes second. The biologists who name species sometimes try to use a descriptor in the epithet. For humans, they could have chosen bipedal or talking or hairless, but they chose thinker. The longer answer to the question of why scientists don’t say what they mean starts with a little chat about jargon. Contrary to the belief of some, jargon is a good thing. Jargon is a set of words and phrases that people who know a lot about a particular subject use to talk together. There’s jargon in every field (scientific or not), every workplace, every town, even every home. Families and close friends almost always use jargon in conversations with one another. Plumbers use jargon to communicate about plumbing. Anatomists and physiologists use jargon and technical terminology, much of which is shared with medicine and other fields of biology, especially human biology.The dorsal cavity consists of two cavities that contain the central nervous system. The first is the cranial cavity, the space within the skull that holds your brain. The second is the spinal cavity, the space within the vertebrae where the spinal cord runs through your body. In the 1970s, computer technology took off, taking medical imaging technology with it. Digital imaging techniques began to be applied to convert multiple flat-slice images into one three-dimensional image. The first technology of this sort was called computed axial tomography (commonly called a CAT or CT scan), in which multiple X-ray images are combined into cross-sectional pictures of structures inside the body. These detailed and extensive images were unlike anything that had been available to anatomists before. CT technology is still an active area of development. Major technology manufacturers maintain robust product lines of CT instruments and accoutrements for use in clinics and clinical research. If you examine a sample of any human tissue under a microscope, you see cells, possibly millions of cells. All living things are made of cells. In fact, having a cellular level of organization is inherent in any definition of organism. We discuss the cellular level of organization in some detail in Chapter 3. Level II: The tissue level

An organ is a part of the body that performs a specialized physiological function. For example, the stomach is an organ that has the specific physiological function of breaking down food. By definition, an organ is made up of at least two different tissue types; many organs contain tissues of all four types. Although we can name and describe all four tissue types that make up all organs, as we do in the preceding section, listing all the organs in the body wouldn’t be so easy. Darwin made scientific history in his own way, of course, but it was a German physicist named Wilhelm Conrad Roentgen who’s remembered as the father of medical imaging. In 1895, Roentgen recorded the first image of the internal parts of a living human: an X-ray image of his wife’s hand. By 1900, X-rays were in widespread use for the early detection of tuberculosis, at that time a common cause of death. X-rays are beams of radiation emitted from a machine toward the patient’s body, and X-ray images show details only of hard tissues, like bone, that reflect the radiation. In this way, they’re similar to photographs. Refinements and enhancements of X-ray techniques were developed all through the 20th century, with extensive use and major advances during World War II. The X-ray is still a widely used method for medical diagnosis screening for signs of disease, usually tumors.Ions: Because electrons are relatively far from the atomic nucleus, they are most susceptible to external fields. Atoms that have gained or lost electrons are transformed into ions. Getting an extra electron turns an atom into a negatively charged ion, or anion, whereas losing an electron creates a positively charged ion, or cation.

Isotopes: Atoms of an element that have a different number of neutrons and a different atomic weight than usual. In other words, isotopes are alternate forms of the same chemical element, so they always have the same number of protons as that element but a different number of neutrons. The fourth shell (which can be found in elements such as potassium, calcium, and iron) holds up to 18 electrons. Higher shells also exist. remember.eps Anatomy is form; physiology is function. You can’t talk about one without talking about the other. The anatomy and physiology of everything elseMedical 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 of the human body. If you’re a visual learner, you may get more out of anatomy and physiology by seeing the real thing in the flesh. If you’re an aural learner, you may learn best in the classroom as the teacher lectures. If you’re a reading and writing kind of learner, you’ll get the most out of our first tip to write stuff down. And if you’re a kinesthetic learner, there’s nothing like touching or holding to commit something to memory. Get a grip on Greek and Latin

Not that human anatomy and physiology aren’t specie-al. Humans’ bipedal posture and style of locomotion are very specie-al. There’s nothing like a human hand anywhere but at the end of a human arm. Most specie-al of all, possibly, is the anatomy and physiology that allows (or maybe compels) humans to engage in science: humankind’s highly developed brain and nervous system. It’s entirely within the norms of evolutionary theory that people would be most interested in their own specie-alties, so more humans find human anatomy and physiology more interesting than the anatomy and physiology of the alga. From here on, we’re restricting our discussion to the anatomy and physiology of our own species. How anatomy and physiology fit into science The test is done and the grades are in. So there was a really tough question or two on the test and you blew it big-time? It’s hardly a missed opportunity — this is where rolling with the punches really pays off. The following list of common anatomical descriptive terms that appear throughout this and every other anatomy book may come in handy:This is a simple idea that far too few students practice regularly. Don’t stop at underlining and highlighting important material in your textbooks and study guides: Write it down. Or type it up. Whatever you do, don’t just regurgitate it exactly as presented in the material you’re studying. Human pathophysiology is the science of human anatomy and physiology gone wrong. (The prefix path- is Greek for suffering.) It’s the interface of human biology and medical science. Clinical medicine is the application of medical science to alleviate an anatomical or physiological problem in an individual human. Acid: A substance that becomes ionized when placed in solution, producing positively charged hydrogen ions, H +. An acid is considered a proton donor. (Remember, atoms always have the same number of electrons as protons. Ions are produced when an atom gains or loses electrons.) Stronger acids separate into larger numbers of H + ions in solution.