Anatomy And Physiology Quotes

In examining disease, we gain wisdom about anatomy and physiology and biology. In examining the person with disease, we gain wisdom about life.

That's because only a real artist knows the actual anatomy of the terrible or the physiology of fear - the exact sort of lines and proportions that connect up with latent instincts or hereditary memories of fright, and the proper colour contrasts and lighting effects to stir the dormant sense of strangeness.

My fundamental premise about the brain is that its workings—what we sometimes call “mind”—are a consequence of its anatomy and physiology, and nothing more. —CARL SAGAN

Any magazine-cover hack can splash paint around wildly and call it a nightmare, or a witches sabbath or a portrait of the devil; but only a great painter can make such a thing really scare or ring true. That's because only a real artist knows the anatomy of the terrible, or the physiology of fear.

But it so happens that everything on this planet is, ultimately, irrational; there is not, and cannot be, any reason for the causal connexion of things, if only because our use of the word "reason" already implies the idea of causal connexion. But, even if we avoid this fundamental difficulty, Hume said that causal connexion was not merely unprovable, but unthinkable; and, in shallower waters still, one cannot assign a true reason why water should flow down hill, or sugar taste sweet in the mouth. Attempts to explain these simple matters always progress into a learned lucidity, and on further analysis retire to a remote stronghold where every thing is irrational and unthinkable. If you cut off a man's head, he dies. Why? Because it kills him. That is really the whole answer. Learned excursions into anatomy and physiology only beg the question; it does not explain why the heart is necessary to life to say that it is a vital organ. Yet that is exactly what is done, the trick that is played on every inquiring mind. Why cannot I see in the dark? Because light is necessary to sight. No confusion of that issue by talk of rods and cones, and optical centres, and foci, and lenses, and vibrations is very different to Edwin Arthwait's treatment of the long-suffering English language. Knowledge is really confined to experience. The laws of Nature are, as Kant said, the laws of our minds, and, as Huxley said, the generalization of observed facts. It is, therefore, no argument against ceremonial magic to say that it is "absurd" to try to raise a thunderstorm by beating a drum; it is not even fair to say that you have tried the experiment, found it would not work, and so perceived it to be "impossible." You might as well claim that, as you had taken paint and canvas, and not produced a Rembrandt, it was evident that the pictures attributed to his painting were really produced in quite a different way. You do not see why the skull of a parricide should help you to raise a dead man, as you do not see why the mercury in a thermometer should rise and fall, though you elaborately pretend that you do; and you could not raise a dead man by the aid of the skull of a parricide, just as you could not play the violin like Kreisler; though in the latter case you might modestly add that you thought you could learn. This is not the special pleading of a professed magician; it boils down to the advice not to judge subjects of which you are perfectly ignorant, and is to be found, stated in clearer and lovelier language, in the Essays of Thomas Henry Huxley.

Although man has included meat in his diet for thousands of years, his anatomy and physiology, and the chemistry of his digestive juices, are still unmistakably those of a frugivorous animal.

Obstetricians also doubted the female intellectual capacity to grasp the anatomy and physiology of childbirth, and suggested that they could not therefore be trained. But the root fear was – guess what? – you’ve got it, but no prizes for quickness: money.

There is no doubt that the Old Testament is a physiological and anatomical textbook to those capable of reading it from a scientific viewpoint.

It was in Alexandria that the circumference of the earth was first measured, the sun fixed at the center of the solar system, the workings of the brain and the pulse illuminated, the foundations of anatomy and physiology established, the definitive editions of Homer produced. It was in Alexandria that Euclid had codified geometry.

Anatomy is to physiology as geography is to history; it describes the theatre of events.

My pre-med studies in anatomy and physiology at Oxford had not prepared me in the least for real medicine.

It was in Alexandria that the circumference of the earth was first measured, the sun fixed at the center of the solar system, the workings of the brain and the pulse illuminated, the foundations of anatomy and physiology established, the definitive editions of Homer produced.

Descartes was very interested in anatomy and physiology and regarded a tiny organ in the center of the brain, called the pineal gland, as the principal seat of the soul. That gland, he believed, was the place where all our thoughts are formed, the wellspring of our free will.

Those who have dissected or inspected many [bodies] have at least learnt to doubt; while others who are ignorant of anatomy and do not take the trouble to attend it are in no doubt at all.

Fortunately, most of our vital physiological functions are involuntary, as some amongst us would forget them.

What do you study?" "As much as we know of the different sciences. We have, within our limits, a good deal of knowledge of anatomy, physiology, nutrition—all that pertains to a full and beautiful personal life. We have our botany and chemistry, and so on—very rudimentary, but interesting; our own history, with its accumulating psychology." "You put psychology with history—not with personal life?" "Of course. It is ours; it is among and between us, and it changes with the succeeding and improving generations. We are at work, slowly and carefully, developing our whole people along these lines. It is glorious work—splendid! To see the thousands of babies improving, showing stronger clearer minds, sweeter dispositions, higher capacities—don't you find it so in your country?

But the fact remains: in terms of physiology and anatomy, we fit together like two jigsaw pieces, much as our voices merged into one, complementing each other, when we sang the song that later became ‘ours’.

Obstetricians also doubted the female intellectual capacity to grasp the anatomy and physiology of childbirth, and suggested that they could not therefore be trained. But the root fear was – guess what? – you’ve got it, but no prizes for quickness: money. Most doctors charged a routine one guinea for a delivery. The word got around that trained midwives would undercut them by delivering babies for half a guinea! The knives were out.

In short, what Brown, Enquist, and West are saying is that evolution structured our circulatory systems as fractal networks to approximate a “fourth dimension” so as to make our metabolisms more efficient. As West, Brown, and Enquist put it, “Although living things occupy a three-dimensional space, their internal physiology and anatomy operate as if they were four-dimensional … Fractal geometry has literally given life an added dimension.

Just as the human body doesn’t have a single “most important” organ, several elements are essential for the creation of life. In the following section, you’ll find information on those elements and their chemical significance (as well as physiological important).

You have to imagine what it was like to be on the receiving end of vicious antagonism: sneering, contempt, ridicule, slights about one’s intelligence, integrity and motives. In those days, women even ran the risk of dismissal for their opinions. And this treatment came from other women, as well as men. In fact, “in-fighting” between various schools of nurses who had some sort of training in midwifery was particularly nasty. One eminent lady – the matron of St Bartholomew’s Hospital – branded the aspiring midwives as “anachronisms, who would in the future be regarded as historical curiosities”. The medical opposition seems to have arisen mainly from the fact that “women are striving to interfere too much in every department of life”.* Obstetricians also doubted the female intellectual capacity to grasp the anatomy and physiology of childbirth, and suggested that they could not therefore be trained. But the root fear was – guess what? – you’ve got it, but no prizes for quickness: money. Most doctors charged a routine one guinea for a delivery. The word got around that trained midwives would undercut them by delivering babies for half a guinea! The knives were out.

The basic sciences of anatomy, physiology, biology, and chemistry are linked to a patient at the bedside through very specific stories that doctors learn and eventually create. These stories, what researchers now call illness scripts, contain key characteristics of a disease to form an iconic version, an idealized model of that particular disease. … It is the story that every doctor puts together for herself with the knowledge she gains from books and patients. The more experience a doctor has with any of these illnesses, the richer and more detailed the illness script she has of the disease becomes.

It is the function which permits us to understand the organism. Thus, when they are inborn, anatomical structures should be considered as topographical conditions of the original functional development, modifiable by the function itself and thus comparable to the electrode which governs the phenomenon of electrolysis but is altered by it in return; when they are acquired, they should be considered the result of the most habitual functioning; thus anatomy should be considered as a stage in the development of physiology. Finally, if it were established that the nerve processes in each situation always tend to re-establish certain states of preferred equilibrium, these latter would represent the objective values of the organism and one would have the right to classify behavior as ordered or disordered, significant or insignificant, with respect to them. These denominations, far from being extrinsic and anthropomorphic, would belong in the living being as such.

When the time came to graduate, he was placed last on the honors list for physiology and comparative anatomy. His professor William Carpenter cited the reason for this slight in a letter to him: “I think it as well to let you know the reason why I found it requisite to place you there.… As answers to my questions, your papers were so defective, that if it had not been for the amount of original observation of which they bore evidence, I could not have placed you in the honours list at all.

[...] we have in our treatise a series of fifty-seven examinations, almost exclusively of injuries of the human body forming a group of observations furnishing us with the earliest known nucleus of fact regarding the anatomy, physiology and pathology of the human body. Crude and elementary as they are, the method by which they were collected was scientific, and these observations, together with the diagnoses and the explanatory commentary in the ancient glosses, form the oldest body of science now extant.

As long as museums and universities send out expeditions to bring to light new forms of living and extinct animals and new data illustrating the interrelations of organisms and their environments, as long as anatomists desire a broad comparative basis human for anatomy, as long as even a few students feel a strong curiosity to learn about the course of evolution and relationships of animals, the old problems of taxonomy, phylogeny and evolution will gradually reassert themselves even in competition with brilliant and highly fruitful laboratory studies in cytology, genetics and physiological chemistry.

Do you consider yourself athletic? How would you rate yourself, say, as a swimmer? Average, below average, maybe a little above average? So-so? Terrible? Well, I’ve got news for you: whether you know it or not, you are a world-class super-Olympic gold medal swimmer. I’m not kidding. You know how I know that? Because I took anatomy, physiology, bacteriology, and chemistry in college, as part of my science minor. And here’s what I learned: we all start out the same way, as tiny sperm cells. In order for you to be born, assuming your daddy had an average sperm count, you had to have out-swum some 200,000 other sperm. And it was uphill all the way. Now, I do not know what motivated you, but that little tail was wiggling like mad, and you were screaming, “Out of my way! Out of my way! I want to teach school! I want to dance! I want to be in real estate! I want to be a journalist!” or whatever it was you were screaming at the top of your little sperm voice.

The Yoruba terms obinrin and okunrin do express a distinction. Reproduction is, obviously, the basis of human existence, and given its import, and the primacy of anafemale [anatomical female] body-type, it is not surprising that the Yoruba language describes the two types of anatomy. The terms okunrin and obinrin, however, merely indicate the physiological differences between the two anatomies as they have to do with procreation and intercourse. They refer, then, to the physically marked and physiologically apparent differences between the two anatomies. They do not refer to gender categories that connote social privileges and disadvantages. Also, they do not express sexual dimorphism because the distinction they indicate is specific to issues of reproduction. To appreciate this point, it would be necessary to go back to the fundamental difference between the conception of the Yoruba social world and that of Western societies.” “… I argued that the biological determinism in much of Western thought stems from the application of biological explanations in accounting for social hierarchies. This in turn has led to the construction of the social world with biological building blocks. Thus the social and the biological are thoroughly intertwined. This worldview is manifested in male-dominant gender discourses, discourses in which female biological differences are used to explain female sociopolitical disadvantages. The conception of biology as being ‘everywhere’ makes it possible to use it as an explanation in any realm, whether it is directly implicated or not. Whether the question is why women should not vote or why they breast-feed babies, the explanation is one and the same: they are biologically predisposed.” “The upshot of this cultural logic is that men and women are perceived as essentially different creatures. Each category is defined by its own essence. Diane Fuss describes the notion that things have a ‘true essence … as a belief in the real, the invariable and fixed properties which define the whatness of an entity.’ Consequently, whether women are in the labor room or in the boardroom, their essence is said to determine their behavior. In both arenas, then, women’s behavior is by definition different from that of men. Essentialism makes it impossible to confine biology to one realm. The social world, therefore, cannot truly be socially constructed.

when we consider DNA, the genotype is the DNA sequence that contains instructions for the living organism. The phenotype is the observable characteristics of an organism, such as its anatomy, biochemistry, physiology, and behavior. The genotype interacts with the environment to produce the phenotype. To put this in an everyday situation, consider the blueprint as a house’s genotype and the actual house its phenotype. The phenotypic construction process is the building of the house using the blueprint as information about what and how to do it. The phenotype is related to the genotype that describes it, but there is a world of physical difference between the genotype and the phenotype and even the phenotypic construction process. For one, the genotype is non-dynamic; it is a quiescent, one-dimensional sequence of symbols (DNA’s symbols are nucleotides) that has no energy or time constraints. Like a blueprint, it can sit around for years, as you have probably learned from watching CSI. The genotype dictates what should be constructed (perhaps a really cute dog), but the DNA itself does not look or act anything like a cute dog. On the other hand, the phenotype (the cute dog) is dynamic and uses energy, especially if it is a border collie.

Cardiac muscle tissue occurs only in the heart (the body’s blood pump), where it constitutes the bulk of the heart walls. Like skeletal muscle cells, cardiac muscle cells are striated (see Figure 4.9b, p. 139), but cardiac muscle is not voluntary. Indeed, it can and does contract without being stimulated by the nervous system. Most of us have no conscious control over how fast our heart beats.

Smooth muscle tissue is found in the walls of hollow visceral organs, such as the stomach, urinary bladder, and respiratory passages.

Its role is to force fluids and other substances through internal body channels. Like skeletal muscle, smooth muscle consists of elongated cells, but smooth muscle has no striations

Muscles are distinguished by their ability to transform chemical energy (ATP) into directed mechanical energy. In so doing, they become capable of exerting force.

■Skeletal and smooth muscle cells (but not cardiac muscle cells) are elongated, and for this reason, they are called muscle fibers.

muscle stretching that occurs during eccentric contractions causes microtears in the muscles.

Skeletal muscles are described as voluntary, but even relaxed muscles are almost always slightly contracted, a phenomenon called muscle tone.

Later another form of ossification known as bone growth goes on until early adulthood as the body increases in size. Bones are capable of growing thicker throughout life. However, ossification in adults serves mainly for bone remodeling and repair.

Before week 8, the skeleton of a human embryo is constructed entirely from fibrous membranes and hyaline cartilage.

Bone tissue begins to develop at about this time and eventually replaces most of the existing fibrous or cartilage structures.

■In endochondral ossification (endo 5 within, chondro 5 cartilage), a bone develops by replacing hyaline cartilage.

The resulting bone is called a cartilage, or endochondral, bone.

Except for the clavicles, essentially all bones below the base of the skull form by endochondral ossification (en0do-kon9dral).

This deterioration opens up cavities, but the bone collar stabilizes the hyaline cartilage model.

The periosteal bud invades the internal cavities and spongy bone forms.

In month 3, the forming cavities are invaded by a collection of elements called the periosteal bud,

which contains a nutrient artery and vein, nerve fibers, red marrow elements, osteogenic cells, and osteoclasts.

The entering osteoclasts partially erode the calcified cartilage matrix, and the osteogenic cells become osteoblasts and secrete osteoid around the remaining calcified fragments of hyaline cartilage, forming bone-covered cartilage trabeculae. In this way, the earliest version of spongy bone forms in a developing long bone.

The diaphysis elongates and a medullary cavity forms.

As the primary ossification center enlarges, osteoclasts break down the newly formed spongy bone and open up a medullary cavity in the center of the diaphysis.

Only a few cells thick, trabeculae contain irregularly arranged lamellae and osteocytes interconnected by canaliculi. No osteons are present. Nutrients reach the osteocytes of spongy bone by diffusing through the canaliculi from capillaries in the endosteum surrounding the trabeculae.

Chemical Composition of Bone Bone contains both organic and inorganic substances. Organic components include bone cells and osteoid. Its inorganic components are mineral salts.

The organic components of bone include its cells (osteogenic cells, osteoblasts, osteocytes, bone-lining cells, and osteoclasts) and osteoid (os9te-oid), the organic part of the matrix.

Osteoid, which makes up approximately one-third of the matrix, includes ground substance (composed of proteoglycans and glycoproteins) and collagen fibers, both of which are made and secreted by osteoblasts. These organic substances, particularly collagen, contribute both to a bone’s structure and to the flexibility and tensile strength that allow it to resist stretch and twisting.

Bone’s resilience is thought to come from sacrificial bonds in or between collagen molecules. These bonds stretch and break easily on impact, dissipating energy to prevent the force from rising to a fracture value. In the absence of continued or additional trauma, most of the sacrificial bonds re-form.

Inorganic Components The balance of bone tissue (65% by mass) consists of inorganic hydroxyapatites (hi-drok0se-ap9ah-tītz), or mineral salts, largely calcium phosphates present as tiny, tightly packed, needlelike crystals in and around collagen fibers in the extracellular matrix. The crystals account for the most notable characteristic of bone—its exceptional hardness, which allows it to resist compression.

The proper combination of organic and inorganic matrix elements makes bone exceedingly durable and strong without being brittle.

Healthy bone is half as strong as steel in resisting compression and fully as strong as steel in resisting tension.

Because of the mineral salts they contain, bones last long after death and provide an enduring “monument.” In fact, skeletal remains many centuries old can still reveal the shapes and sizes of ancient peoples, the kinds of work they did, and many of the ailments they suffered, such as arthritis. Growth arrest lines, horizontal lines on long bones, provide visible proof of illness when the body uses nutrients to fight disease and the bones stop growing.

Osteocytes The spidery osteocytes (Figure 6.5) are mature bone cells that occupy spaces (lacunae) that conform to their shape.

Osteocytes monitor and maintain the bone matrix.

Our brains, not our bones, convey feelings of fatigue.

Hyaline Cartilages Hyaline cartilages, which look like frosted glass when freshly exposed, provide support with flexibility and resilience. They are the most abundant skeletal cartilages. Their chondrocytes are spherical (see Figure 4.8g), and the only fiber type in their matrix is fine collagen fibers (which are undetectable microscopically). Colored blue in Figure 6.1, skeletal hyaline cartilages include

Elastic Cartilages Elastic cartilages resemble hyaline cartilages (see Figure 4.8h), but they contain more stretchy elastic fibers and so are better able to stand up to repeated bending. They are found in only two skeletal locations, shown in green in Figure 6.1—the external ear and the epiglottis (the flap that bends to cover the opening of the larynx each time we swallow).

The appendicular skeleton (ap0en-dik9u-lar) consists of the bones of the upper and lower limbs and the girdles (shoulder bones and hip bones) that attach the limbs to the axial skeleton (colored gold in Figure 6.1). Bones of the limbs help us move from place to place (locomotion) and manipulate our environment.

Diaphysis A tubular diaphysis (di-af9ĭ-sis; dia 5 through, physis 5 growth), or shaft, forms the long axis of the bone. It is constructed of a relatively thick collar of compact bone that surrounds a central medullary cavity (med9u-lar-e; “middle”), or marrow cavity. In adults, the medullary cavity contains fat (yellow marrow) and is called the yellow marrow cavity.

Epiphyses The epiphyses (e-pif9ĭ-sēz; singular: epiphysis) are the bone ends (epi 5 upon). In many cases, they are broader than the diaphysis. An outer shell of compact bone forms the epiphysis exterior and their interior contains spongy bone. A thin layer of articular (hyaline) cartilage covers the joint surface of each epiphysis, cushioning the opposing bone ends during movement and absorbing stress.

A delicate connective tissue membrane called the endosteum (en-dos9te-um; “within the bone”) covers internal bone surfaces (Figure 6.4).

The endosteum covers the trabeculae of spongy bone and lines the canals that pass through the compact bone.

Like the periosteum, the endosteum contains osteogenic cells that can differentiate into other bone cells.

Hematopoietic tissue, red marrow, is typically found within the trabecular cavities of spongy bone of long bones and in the diploë of flat bones.

For this reason, both these cavities are often called red marrow cavities.

In newborn infants, the medullary cavity of the diaphysis and all areas of spongy bone contain red bone marrow.

In most adult long bones, the fat-containing medullary cavity extends well into the epiphysis, and little red marrow is present in the spongy bone cavities.

For this reason, blood cell production in adult long bones routinely occurs only in the heads of the femur and humerus (the long bone of the arm).

Bone Markings The external surfaces of bones are rarely smooth and featureless.

Instead, they display projections, depressions, and openings.

These bone markings serve as sites of muscle, ligament, and tendon attachment, as joint surfaces, or as conduits for blood vessels and nerves.

Projections—bone markings that bulge outward from the surface—include heads, trochanters, spines, and others.

Bone markings that are depressions and openings include fossae (singular: fossa), sinuses, foramina (singular: foramen), and grooves. They usually allow nerves and blood vessels to pass.

Five major cell types populate bone tissue:

osteogenic cells, osteoblasts, osteocytes, bone lining cells, and osteoclasts.

All of these except for the osteoclasts originate from mesenchymal cells. Each cell type is essentially a specialized form of the same basic cell type that transforms to a mature or functional form that serves bone growth in some specific way (Figure 6.5). Bone cells, like other connective tissue cells, are surrounded by an extracellular matrix of their making.

When actively depositing matrix, osteoblasts are cube shaped. When inactive, they resemble the flattened osteogenic cells or may differentiate into bone lining cells. When the osteoblasts become completely surrounded by the matrix being secreted, they become osteocytes.

Ossification and osteogenesis (os0te-o-jen9ĕ-sis) are synonyms meaning the process of bone formation (os 5 bone, genesis 5 beginning).

In embryos this process leads to the formation of the bony skeleton.

■In intramembranous ossification, a bone develops from a fibrous membrane and the bone is called a membrane bone.

The beauty of using flexible structures (membranes and cartilages) to fashion the embryonic skeleton is that they can accommodate mitosis. Were the early skeleton composed of calcified bone tissue from the outset, growth would be much more difficult.

Beginning late in the second month of development, this process uses hyaline cartilage “bones” formed earlier as models, or patterns, for bone construction.

It is more complex than intramembranous ossification because the hyaline cartilage must be broken down as ossification proceeds.

Cartilage in the center of the diaphysis calcifies and then develops cavities.

■Articular cartilages, which cover the ends of most bones at movable joints ■Costal cartilages, which connect the ribs to the sternum (breastbone) ■Respiratory cartilages, which form the skeleton of the larynx (voicebox) and reinforce other respiratory passageways ■Nasal cartilages, which support the external nose

Fibrocartilages Highly compressible with great tensile strength, fibrocartilages consist of roughly parallel rows of chondrocytes alternating with thick collagen fibers (see Figure 4.8i).

flat, or irregular (Figure 6.2). ■Long bones, as their name suggests, are considerably longer than they are wide (Figure 6.2a). A long bone has a shaft plus two ends which are often expanded. All limb bones except the patella (kneecap) and the wrist and ankle bones are long bones. Notice that these bones are named for their elongated shape, not their overall size. The three bones in each of your fingers are long bones, even though they are small.

■Short bones are roughly cube shaped. The bones of the wrist and ankle are examples (Figure 6.2d). Sesamoid bones (ses9ah-moid; “shaped like a sesame seed”) are a special type of short bone that form in a tendon (for example, the patella). They vary in size and number in different individuals.

■Irregular bones have complicated shapes that fit none of the preceding classes. Examples include the vertebrae and the hip bones (Figure 6.2b).

■ Mineral and growth factor storage. Bone is a reservoir for minerals, most importantly calcium and phosphate. The stored minerals are released into the bloodstream in their ionic form as needed for distribution to all parts of the body. Indeed, “deposits” and “withdrawals” of minerals to and from the bones go on almost continuously. Additionally, mineralized bone matrix stores important growth factors.

■Blood cell formation. Most blood cell formation, or hematopoiesis (hem0ah-to-poi-e9sis), occurs in the red marrow cavities of certain bones.

■Triglyceride (fat) storage. Fat, a source of energy for the body, is stored in bone cavities.

■Flat bones are thin, flattened, and usually a bit curved. The sternum (breastbone), scapulae (shoulder blades), ribs, and most skull bones are flat bones (Figure 6.2c).

■Support. Bones provide a framework that supports the body and cradles its soft organs. For example, bones of lower limbs act as pillars to support the body trunk when we stand, and the rib cage supports the thoracic wall.