Reductionism and holism; how they differ and why both ideas are relevant to the study of human anatomy and physiology and to the clinical care of patients 3. Simple columnar and pseudostratified columnar epithelia often have wineglass-shaped goblet cells that produce protective the cells and extracellular material of an epithelium can be loosely compared to the bricks and mortar of a wall. It is concerned with color vision, object recognition, and visual memory, including our ability to read, recognize faces, and identify other things we see. This pressure causes tingling and muscular weakness in the palm and medial side of the hand and pain that may radiate to the arm and shoulder. Recurring patches of scaly white or yellowish inflammation often on the head, face, chest, and back; called cradle cap (a yellow, crusty scalp lesion) in infants. Free ribosomes within the nucleus and mitochondria make proteins for use in those organelles. When they contract, they constrict the opening and tend to prevent the passage of material through it. In the absence of local standards, consultation with peer countries and experts is recommended. In addition, emphasis has been placed on antibody-directed prodrug therapy, gene-directed prodrug therapy, bacterial-directed prodrug therapy and viral-directed prodrug therapy, all of which have been supported by research. A frontal (coronal) plane also extends vertically, but it is perpendicular to the sagittal plane and divides the body into anterior (front) and posterior (back) portions (fig. Muscles of the anterior and posterior compartments function mainly as extensors and flexors of the knee, respectively, and are treated in table 10. Recall that the right subclavian artery arises from the brachiocephalic trunk and the left subclavian artery arises directly from the aortic arch (see fig. For example, the spinal cord can integrate the stretch sensation from a full bladder with cerebral input concerning the appropriate time and place to urinate and execute control of the bladder accordingly. In many Types of Levers There are three classes of levers that differ with respect to which component is in the middle-the fulcrum (F), effort (E), or resistance (R) (fig. Astrocytes absorb these and prevent them from reaching excessive levels in the tissue fluid. Muscles of the lateral compartment of the leg: fibularis brevis and fibularis longus (table 10. Usually triggered by septicemia but also occurs when blood circulation slows markedly (as in cardiac arrest). Because long-term use of steroids weakens the bone, however, aspirin is the treatment of first choice to control the inflammation. They help to bind adjacent vertebrae together, support the weight of the body, allow spinal mobility, and absorb shock. They enable the cells to resist stress, communicate with each other, and control the movement of substances through tissues. Digestive juices cause immediate chemical inflammation of the peritoneum, followed by microbial inflammation as intestinal bacteria invade the body cavity. Reverberating circuits may also be involved in short-term memory, as discussed in the next section, and they may play a role in the uncontrolled "storms" of neural activity that occur in epilepsy. Sensitivity is also low, as consistently supported in studies comparing echocardiography and auscultation from several countries. The muscles shorten as they atrophy, causing postural abnormalities such as scoliosis. Olfactory neurons synapse with mitral cells and tufted cells in the, which lies inferior to the frontal lobe. When a stimulus ceases, the nervous system stops responding almost immediately, whereas hormonal effects can last for days or even longer. Anterior Muscles of the Hip Most muscles that act on the femur originate on the hip bone. Other agents such as Streptococcus pneumoniae, Streptococcus pyogenes, and Listeria monocytogenes are rare causes of endocarditis.
Note the round cross-sectional shape of straight hair (a, b) compared to the flatter shape of wavy hair (c, d). Rheumatic joint involvement is notoriously variable, ranging from the classic migratory polyarthritis of large joints, to monoarthritis, polyarthralgia, and monoarthralgia. They create a strong structural bond between cells and extracellular macromolecules and help to hold tissues together. When a smooth muscle cell contracts, it puckers and twists somewhat like wringing out a wet towel (fig. The elements are represented by one- or two-letter symbols, usually based on their English names: C for carbon, Mg for magnesium, Cl for chlorine, and so forth. The superior surface of rib 1 has a pair of shallow grooves that serve as platforms for the subclavian artery and subclavian vein. Tissue distribution of lymphocytes in rheumatic heart valves as defined by monoclonal anti-T cell antibodies. The carotid sinus has a relatively thin tunica media and an abundance of glossopharyngeal nerve fibers in the tunica externa. As articular cartilage 31 degenerates, the joint begins to ossify, and sometimes the bones become solidly fused and immobilized, a condition called ankylosis32 (fig. Each year, thousands of athletes from the high-school to professional level sustain some type of injury to their muscles, as do the increasing numbers of people who have taken up running and other forms of physical conditioning. This activates protein phosphatases, which dephosphorylate synaptic proteins such as actin microfilaments that support dendritic spines. As the cuff pressure continues to decline, a bump can be heard every time the artery collapses-that is, once in each heartbeat. A number of major challenges need to be considered, including teratogenic risks, dosing complexities of the various anticoagulation regimens, and anticoagulation management around the time of labor. Meta-analysis of clinical outcomes following surgical mitral valve repair or replacement. Since the right brain controls motor responses on the left side of the body and vice versa, each side of the brain sees what is on the side of the body where it exerts motor control. They may be only faintly visible, however, unless the tissue has been specially stained for them. Clinical and necropsy observations early after simultaneous replacement of the mitral and aortic valves. The well-known durability of the epidermis depends in part on its desmosomes, depicted in figure 5. In the respiratory tract, the mucus clogs the cilia and prevents them from beating freely. What system in the brain connects our conscious thoughts and feelings with the autonomic control centers of the hypothalamus Intermittent attacks of paleness, cyanosis, and pain in the fingers and toes, caused when cold or emotional stress triggers excessive vasoconstriction in the digits; most common in young women. A flagellum does not beat with power and recovery strokes like those of a cilium, but in a more undulating, snakelike or corkscrew fashion. The esophagus is protected from abrasion by a keratinized stratified squamous epithelium. In capillary beds supplied with metarterioles, there is often a single smooth muscle cell that wraps like a cuff around the opening to each capillary; it acts as a precapillary sphincter regulating blood flow. The vitreous43 body is a transparent jelly that fills a space called the vitreous chamber behind the lens. Prodrug Approaches for Natural Products 293 neuropsychiatric diseases (Tarrago et al. A polygenic (top): Monica Lau/Getty Images; (middle): Anthony Saint James/Getty Images; (bottom): JupiterImages/Comstock/Getty Images trait such as eye color is determined by the contributions of genes at multiple loci. At the atlantoaxial joint, the dens of the axis projects into the vertebral foramen of the atlas and is held against the anterior arch of the atlas by the transverse ligament (see fig. Name an antagonist of each of these muscles: the depressor anguli oris, orbicularis oculi, and levator labii superioris.
An overview on two valuable natural and bioactive compounds, thymol and carvacrol, in medicinal plants. When stimulated by chemical signals, stretch, and other stimuli, muscle cells respond with electrical changes across the plasma membrane. These gates respond to three types of stimuli: ligand-gated channels respond to chemical messengers, voltage-gated channels to changes in electrical potential (voltage) across the plasma membrane, and mechanically gated channels to physical stress on a cell, such as stretch and pressure. They bind the components of a tissue together and mark paths that guide migrating embryonic cells to their destinations in a tissue. The tunica media consists of 40 to 70 layers of elastic sheets, perforated like slices of Swiss cheese rolled into a tube, alternating with thin layers of smooth muscle, collagen, and elastic fibers. It often results from excessive stretch (as in an ankle sprain or pulled muscle), but can have other causes. Examples of ionizing radiation include ultraviolet rays, X-rays, and three kinds of radiation produced by nuclear decay: alpha particles, beta particles, and gamma rays. The monoamine hormones include dopamine, epinephrine, norepinephrine, melatonin, and thyroid hormone. Hyperextension is employed in looking up toward the sky or bending over backward (fig. Our bodies, for example, are covered with millions of hairs, each equipped with a useless little arrector muscle. Glossopharyngeal Nerve Mixed Sensory: Taste; touch, pressure, pain, and temperature sensations from tongue and outer ear; regulation of blood pressure and respiration Motor: Salivation, swallowing, gagging Sensory: Pharynx; middle and outer ear; posterior one-third of tongue (including taste buds); internal carotid artery Motor: Medulla oblongata Sensory: Medulla oblongata Jugular foramen Motor: Parotid salivary gland; glands of posterior tongue; stylopharyngeal muscle (which dilates pharynx during swallowing) X. As an infant begins to crawl and lift its head, the cervical region becomes curved toward the posterior side, enabling an infant on its belly to look up. In a reverberating circuit, neurons stimulate each other in a linear sequence from input to output neurons, but some of the neurons late in the path send axon collaterals back to neurons earlier in the path and restimulate them. Mammary gland structure and development and how mammary glands relate to a type of sweat glands 6. But the forest canopy is a challenging world, with dim and dappled sunlight, swaying branches, shifting shadows, and prey darting about in the dense foliage. Therefore, the radiation that reaches the surface of the earth falls within that range, and vision is adapted to take advantage of the wavelenths available to us. Connective tissue cells attack foreign invaders, and connective tissue fiber forms a "battlefield" under the skin and mucous membranes where immune cells can be quickly mobilized against disease agents. Some tendons cross multiple joints before inserting on a middle or distal phalanx, and can flex or extend all the joints they cross. A variety of study designs have been used to address this issue, including case-control studies, cross-sectional studies, and cohort studies. Consensus guidelines on pediatric acute rheumatic fever and rheumatic heart disease. Foods high in soluble fiber (such as beans, apples, and oat bran) lower blood cholesterol by an interesting mechanism: the liver normally converts cholesterol to bile acids and secretes them into the small intestine to aid fat digestion. The right atrium and both auricles exhibit internal ridges of myocardium called pectinate9 muscles. The nature of the primary through quaternary levels of protein structure, and how an alpha helix differs from a beta sheet 14. Motor (efferent) neurons send signals predominantly to muscle and gland cells, the effectors. To explore and to accomplish nature-based prodrugs skillful operations are essential. Drugs that are safe for most people can have serious side effects in others, owing to genetic variations in drug metabolism. On an articulated skeleton, you must look for its vertebral attachment just below the base of the neck; much of this rib lies above the level of the clavicle (fig. They give the cell its shape, resist stress, and participate in junctions that attach cells to their neighbors. Hydrophobic odorants are transported to the receptor by an odorant-binding protein in the mucus. The thermal stability of water helps to stabilize the internal temperature of the body.
Estimating the risk of acute rheumatic fever in New Zealand by age, ethnicity and deprivation. Sternum: Suprasternal notch Manubrium Angle Body Xiphoid process Linea alba Costal margin Linea semilunaris External oblique m. The difference between the carbon backbone and the functional group(s) of an organic molecule; the physiological relevance of functional groups 3. Plasma cells are rarely seen except in the wall of the intestines and in inflamed tissue. The muscle compartment between this membrane and the skin is called superficial perineal space, and the compartment between the perineal membrane and levator ani is the deep perineal space. Their daughter cells push toward the surface and become flatter (more scaly) as they migrate farther upward, until they finally die and flake off. What brain regions serve the sense of smell and how do they differ in their olfactory functions Hearing is a response to vibrating air molecules, and equilibrium is the sense of body orientation, movement, and balance. The gland product may be something synthesized by its cells (such as digestive enzymes) or something removed from the tissues and modified by the gland (such as urine and bile pigments). Some organs of the abdominal cavity lie against the posterior body wall and are covered by peritoneum only on the side facing the peritoneal cavity. It diverges like a fan from the calcaneus to the bases of all the toes, and is a common site of painful inflammation (see Deeper Insight 10. This nerve used to be named the spinal accessory, referring to its origins in the spinal cord. Through the dense bodies and cytoskeleton, force is transferred to the plasma membrane and the entire cell shortens. If ischemia (poor blood flow) persists for more than 2 to 4 hours, nerves begin to die, and after 6 hours, so does muscle tissue. By their role in calcitriol synthesis, keratinocytes influence intestinal absorption of calcium; calcium is needed for the secretion of all digestive enzymes and mucus. Resting allows reduction of workload on the heart and may prevent progression of the inflammatory process. Calmodulin then activates an enzyme called myosin light-chain kinase, which adds a phosphate group to a small regulatory protein on the myosin head. These included the following: annuloplasty (95%); chordal shortening (75%); chordal transfer (10%); chord resection (7%); pericardial leaflet extension (7. Some muscles insert not on bones but on the fascia or tendon of another muscle or on collagen fibers of the dermis. A deficiency of vitamin B12 also causes anemia, but B12 is so abundant in meat that a deficiency is rare except in strict vegetarians. From time immemorial, people have seen blood flow from the body and, with it, the life of the individual. The most common secondary structures are a springlike shape called the alpha helix and a pleated, ribbonlike shape, the beta sheet (-pleated sheet). Write the plural form of each of the following: villus, tibia, encephalitis, cervix, stoma. The five muscles of the medial compartment act primarily as adductors of the thigh (see fig. Branches of the Subclavian and Axillary Arteries the thoracic wall is also supplied by branches of the subclavian arteries and their continuations, the axillary arteries, in the shoulder and axillary regions. Excessive joint stress, however, can hasten the progression of osteoarthritis by damaging the articular cartilage (see Deeper Insight 9. Anterograde transport employs a motor protein called kinesin16 and retrograde transport uses one called dynein17 (the same protein responsible for the motility of cilia and flagella). Two of the nerves arising from these plexuses, the radial and sciatic, are sites of unique nerve injuries described in Deeper Insight 13. This equilibrium can be upset, however, by a surplus of hydrogen ions, which drives the reaction to the left, or adding carbon dioxide and driving it to the right. The clinical findings of rheumatic carditis can be variable, ranging in severity from mild subclinical involvement (up to 53%)24 to severe carditis (20%), leading to acute heart failure. They may recover these functions later and become capable of ejaculating and fathering children, but without sexual sensation. No one passenger moves from the door to the rear, but the crowding and transfer of energy from person to person forces even those at the rear to move a little, like the sodium ions at the next node.
You can well imagine the importance of these reflexes to the coordination of such common movements as walking and dancing. Oncologists are especially interested in two families of cancer genes called oncogenes and tumor suppressor genes. In both cases, one bone (the humerus or femur) has a smooth hemispherical head that fits into a cuplike socket on the other (the glenoid cavity of the scapula or the acetabulum of the hip bone). Their action is most clearly visualized when you cross your legs to rest an ankle on your knee, causing your femur to rotate and the knee to point laterally. Inactive ribosomes occur in the cytosol in two pieces-a small subunit and a large subunit. The abdominal aponeuroses converge on a median fibrous band on the abdomen called the. Atrial fibrillation and infective endocarditis are usually associated with chronic valve disease. There are three ways of controlling vasomotor activity: local, neural, and hormonal mechanisms. This constitutes about 5% of the circulating blood going to meet the metabolic needs of the heart, even though the heart is only 0. They now serve little or no purpose or, in some cases, have been converted to new functions. Each chromatid is now regarded as a separate, single-stranded daughter chromosome. The Hakkis formula is a simplified version of the Gorlin formula that is easier to remember, as it ignores the empiric constant, heart rate, and diastolic filling period/systolic ejection period. Examples include the coronal, sagittal, and lambdoid sutures that border the parietal bones. They are modified apocrine sweat glands that produce a richer secretion and channel it through ducts to a nipple for more efficient conveyance to the offspring. Weak attraction between polarized molecules or between polarized regions of the same molecule. The prefrontal cortex (frontal association area) is the most rostral part of the frontal lobe, just behind the forehead. Therefore, edema is a common problem among people confined to bed or a wheelchair. Tonicity is the ability of a solution to affect the fluid volume and pressure in a cell. Slow-twitch fibers, especially, produce more mitochondria and glycogen and acquire a greater density of blood capillaries as a result of conditioning. In more subtle ways, all day long, your brain monitors input from the spindles of opposing muscles and makes fine adjustments in muscle tension to maintain your posture and coordination. The muscles relax, and the vital signs (body temperature, blood pressure, and heart and respiratory rates) fall. When it obstructs 75% or more of the arterial lumen, it begins to cause symptoms such as angina pectoris. Watch an online video of a crawling millipede and you will see that each leg takes individual jerky steps, but all the legs working together produce a smooth gliding movement, like the glide of a thick muscle filament walking along a thin one. The temperature of a substance is a measure of rate of this motion, and adding heat to a substance increases molecular motion. Over the summer of 1921, they removed the pancreases from dogs to render them diabetic and tied off the pancreatic ducts in other dogs to make most of the pancreas degenerate while leaving the islets intact. It binds to membrane channels and changes their permeability to other solutes, in some cases altering the membrane potential (voltage) of the cell. Structural differences between the valves; anatomy and function of the papillary muscles and tendinous cords 7. The Humerus the humerus has a hemispherical head that articulates with the glenoid cavity of the scapula (fig.
The right transverse sinus receives blood mainly from the superior sagittal sinus, and the left one drains mainly the straight sinus. Myelin further speeds signal conduction by a mechanism to be explained in section 12. Molecular Mimicry, Autoimmunity and Infection: the Cross-Reactive Antigens of Group A Streptococci and Their Sequelae. Lacking sympathetic stimulation to the blood vessels, a patient may exhibit neurogenic shock in which the vessels dilate and blood pressure drops dangerously low. The right occipital lobe thus monitors the left side of the visual field and the left occipital lobe monitors the right side. In situ biomolecule production by bacteria; A synthetic biology approach to medicine. Bilirubin can accumulate enough to discolor the skin, however, in such situations as a rapid rate of erythrocyte destruction; when diseases such as cancer, hepatitis, and cirrhosis compromise liver function; and in premature infants, where the liver is not well enough developed to dispose of bilirubin efficiently. Its ground substance is the blood plasma and its cellular components are collectively called the formed elements. Tapping the patellar ligament with a reflex hammer abruptly stretches the quadriceps femoris muscle of the thigh (fig. The functional unit of a muscle fiber is the, a segment from one Z disc to the next. Sodium and potassium channels open and close just as they did at the trigger zone, and a new action potential is produced. The middle suprarenal arteries arise laterally from the aorta, usually at the same level as the superior mesenteric artery. The hormone prolactin triggers intracellular reactions that activate a regulatory protein and lead ultimately to the secretion of casein. The Orbital and Nasal Regions the orbicularis oculi is a sphincter of the eyelid that encircles and closes the eye. Since it is connected to the lumbar plexus by fibers that run through the lumbosacral trunk, the two plexuses are sometimes referred to collectively as the lumbosacral plexus. Sketch a cross section of the spinal cord showing the anterior and posterior horns. Similar effects are seen in some burn patients who are immobilized and extensively bandaged (including the eyes) and thus suffer prolonged lack of sensory input. Each activated enzyme in the pathway produces a larger number of enzyme molecules at the following step. Identify each of the following spinal tracts-the gracile fasciculus and the lateral corticospinal, lateral reticulospinal, and spinothalamic tracts-with respect to whether it is ascending or descending; its origin and destination; and what sensory or motor purposes it serves. The pericardium, its two layers, the space and fluid between the layers, and its function 4. As fitness trainers and exercise enthusiasts know, there are two kinds of exercise with different effects on muscles-resistance and endurance exercise. The following suggestions may help you develop a rational strategy for learning the muscular system: 1 0. In the intercellular spaces, there are senile plaques consisting of aggregations of cells, altered nerve fibers, and a core of -amyloid protein-the breakdown product of a glycoprotein of plasma membranes. Neurogenic shock is a form of venous pooling shock that results from a sudden loss of vasomotor tone, allowing the vessels to dilate. Thus, everyone has a unique pattern of friction ridges; not even identical twins produce identical fingerprints. These respond not only to taste but, like filiform papillae, also to food texture. We will consider factors that influence each of these variables, but bear in mind that heart rate and stroke volume are somewhat interdependent. They supply the posterior intercostal tissues, vertebrae, spinal cord, and deep muscles of the back. As osteoblasts become trapped in their own hardening matrix, they become osteocytes. To best understand the cranial nerves, you should be familiar with the general structure of nerves and ganglia, afferent and efferent nerve fibers, and the distinction between sensory, motor, and mixed nerves (see section 13.
Protein synthesis, we have seen, is the domain of the ribosomes; protein disposal is the function of another structurally simple organelle called a proteasome. This ensures that anything leaving the blood must pass through the cells and not between them. Many enzymes have two active sites, enabling them to bind two different substrates and bring them together in a way that makes them react more readily with each other. Blood throughout the circulatory system would flow and stop, flow and stop, and put great stress on the small vessels. Basement membranes Building Your Medical Vocabulary State a meaning of each word element, and give a medical term from this chapter that uses it or a slight variation of it. The median body of the hyoid is flanked on either side by hornlike projections called the greater and lesser horns (cornua). This is a change in terminology more than a change in structure or function, as a tendon connects muscle to bone and a ligament connects bone to bone. Human melanoma xenografts and leukemia (In vitro) Opoid painkiller which Jana et al. Alcohol and opium were often used as anesthetics, but the dosage was poorly controlled; some patients were underanesthetized and suffered great pain anyway, and others died of overdoses. In those with significant mitral stenosis, clinical signs of aortic valve disease may be less evident. Some cra nial nerves have changed names, however, since that mnemonic was invented. Muscles enable chewing and swallowing; muscles control voluntary aspect of defecation; abdominal muscles produce vomiting; abdominal and lumbar muscles protect digestive organs. Thus, muscle contraction cannot be understood without first understanding the relationship between nerve and muscle cells. Several other types of fractures are routinely taught in clinical and first aid courses. However, dose-response and toxicological profile along with physiological variability between individuals are yet to be clinical evaluated. Marfan syndrome is present in about 1 out of 20,000 live births, and most victims die by their mid-30s. Such compartmentalization occurs in the thoracic and abdominal walls, pelvic floor, and limbs. The motor fibers control muscles of the gluteal and perineal regions, thigh, leg, and foot. Local anesthetics such as procaine (Novocaine) and tetracaine selectively deaden specific nerves. Later chapters further demonstrate that the evolutionary perspective provides a meaningful understanding of why humans are the way we are. Marazzi/Science Source (a) (b) Birthmarks, or hemangiomas,17 are patches of skin discolored by benign tumors of the blood capillaries. The sympathetic division adapts the body in many ways for physical activity-it increases alertness, heart rate, blood pressure, pulmonary airflow, blood glucose concentration, and blood flow to cardiac and skeletal muscle, but at the same time, it reduces blood flow to the skin and digestive tract. Prodrug Approaches for Natural Products 299 of curcumin as a promising prodrug, with a potential to act as an adjuvant in clinical studies, has been extensively investigated (Peng et al. Its signals travel toward the soma, but bypass it and continue along the central fiber for a short remaining distance to the spinal cord. Others, such as the joints between the wrist and ankle bones and between the articular processes of the vertebrae, have more limited mobility. A connective tissue joint (articular) capsule encloses the cavity and retains the fluid. You can simulate this effect by pressing gently on the corner of one eyelid as you look at this text; the image of the text will fall on noncorresponding regions of the two eyes and cause you to see double.
Our hands are said to be because they can encircle an object such as a branch or tool. Moreover, studies are required to identify additional metabolites, and the influence of drug interactions of psilocybin. By fixing the hyoid from below, they enable the suprahyoid muscles to open the mouth. Some myoblasts remain as unspecialized satellite cells between the muscle fiber and endomysium. If you make the opposite action, so the forearm points away from your trunk, your humerus undergoes lateral body part in the same plane. This stable disulfide prodrug owes its anti-proliferative activity to unique caged bicyclic peptide structure. Taste (gustatory) cells are more or less banana-shaped and have a tuft of apical microvilli called taste hairs, which serve as receptor surfaces for tastants. Indeed, the more commonly recognized problem in these settings is erroneous labeling of individuals as being penicillin allergic when in fact they are notewhen investigated, only around 10% of individuals with a penicillin allergy label in fact are allergic. The axons of these neurons are called the firstthrough third-order nerve fibers (fig. The auricle is an arrangement of named whorls and recesses that direct sound into the auditory canal (fig. A subset of mouse monoclonal antibodies crossreactive with cytoskeletal proteins and group A streptococcal M proteins recognizes N-acetyl-beta-Dglucosamine. Thus, each spinal nerve branches on both ends-into anterior and posterior roots approaching the spinal cord, and anterior and posterior rami leading away from the vertebral column. The role of the thalamus in motor and sensory circuits is further discussed later in this chapter and chapter 16. His tragic decline and death shocked the world and helped put an end to the radium tonic fad. Cells therefore work together at certain tasks and form tissues that carry out a particular function, such as nerve signaling or nutrient digestion. Isotonic12 contraction-contraction with a change in length but no change in tension-begins when internal tension builds to the point that it overcomes the resistance. It matures as it travels, producing new enzymes that modify the cargo in different ways. Growth hormone is a different matter and warrants further exploration at this point. In most vertebrates (fish, amphibians, reptiles, and birds), this sac encloses the egg yolk, transfers its nutrients to the growing embryo, and produces the forerunners of the first blood cells. Good examples of lateral and medial rotation of the humerus are its movements in the forehand and backhand strokes of tennis. Thus, long-term high doses of testosterone can, paradoxically, have feminizing effects. Paclitaxel and docetaxel resistance: Molecular mechanisms and development of new generation taxanes. Through these fibers, the brain constantly but subconsciously monitors the length and tension of nearly every skeletal muscle throughout the body. This phenomenon goes by two names: temporal10 summation, because it results from two stimuli arriving close together in time, or wave summation, because it results from one wave of contraction added to another. Its name literally means "plowshare," which refers to its resemblance to the blade of a plow. Consider, for example, the action of the brachialis muscle on the ulna when it flexes the elbow (fig. Each foramen is bordered by a bony vertebral arch composed of two parts on each side: a pillarlike pedicle32 and platelike lamina. The inferior and superior orbital fissures form a sideways V whose apex lies near the optic canal. In a noisy city, for example, a person can sleep through traffic sounds but wake promptly to the sound of an alarm clock or a crying baby. This inhibits the regrowth of veins and the flow of fresh blood through the organ, and often leads to necrosis.