By A. Goose. Metropolitan State College of Denver.
The difference between systolic pressure and diastolic pressure is the pulse pressure tadacip 20mg mastercard. We will discuss these THE LYMPHATIC CIRCULATION three pressure types thoroughly in Chapter 15 buy tadacip 20mg on-line. This fluid eventually returns from the interstitial space to the TRANSPORT IN THE CARDIOVASCULAR systemic circulation via another set of vessels discount tadacip 20 mg overnight delivery, the lym- SYSTEM phatic vessels. This movement of fluid from the systemic The cardiovascular system depends on the energy provided and pulmonary circulation into the interstitial space and by hemodynamic pressure gradients to move materials over then back to the systemic circulation via the lymphatic ves- long distances (bulk flow) and the energy provided by con- sels is referred to as the lymphatic circulation (see Chapter centration gradients to move material over short distances 16). Both types of movement are the result of differ- mulates in the interstitial space. Diffusion occurs be- CONTROL OF THE CIRCULATION cause of differences in chemical concentration. The healthy cardiovascular system is capable of providing appropriate blood flow to each of the organs and tissues of the body under a wide range of conditions. This is done by Hemodynamic Pressure Gradients Drive Bulk • Maintaining arterial blood pressure within normal limits Flow; Concentration Gradients Drive Diffusion • Adjusting the output of the heart to the appropriate level Blood circulation is an example of transport by bulk flow. Diffusion is The regulation of arterial pressure, cardiac output, and accomplished by the random movement of individual mol- regional blood flow and capillary exchange is achieved by ecules and is an effective transport mechanism over short using a variety of neural, hormonal, and local mecha- distances. Select the (E) Hydrostatic pressure JS, Sheriff DD, Robotham JL, Wise, ONE lettered answer or completion that is 4. Exercise: Regulation and the (C) Blood vessel diameter exceeds a Integration of Multiple Systems. New (A) Square of the radius certain value (B) Square root of the length York: Oxford University Press, (D) Reynolds number exceeds a certain (C) Fourth power of the radius 1996;649–704. The volume of an aorta is increased by (E) Square root of the radius NJ: Humana Press, 2000. New York: Oxford University (A) Can only be caused by changes in compliance of the aorta is Press, 1993. In the tube in the of the blood vessel diagram to the right, the inlet pressure is 75 mm (D) Cause proportional changes in Hg and the outlet blood flow pressure at A and B is 25 (E) Are proportional to the length of a mm Hg. The pressure measured in either the (A) 2 PRU 5 mL/min arterial or the venous circulation when (B) 0. Electrical activity spreads across the atria, through the atri- lective opening and closing of plasma membrane channels oventricular (AV) node, through the Purkinje system, and for sodium, potassium, and calcium ions. Norepinephrine increases pacemaker activity and the calcium channels and the closing of potassium channels. Acetylcholine decreases pacemaker activity and the speed channels and the closing of sodium and calcium of action potential conduction. Pacemaker potentials are achieved by the opening of chan- regions of the heart are recorded by an electrocardiogram nels for sodium and calcium ions and the closing of chan- (ECG). Electrical activity is normally initiated in the sinoatrial (SA) rhythm, pattern of depolarization, and mass of electrically node where pacemaker cells reach threshold first. After initia- potential; phase 3 is the repolarization to the resting mem- tion, the electrical activity spreads throughout the heart, brane potential; and phase 4 is the resting membrane po- reaching every cardiac cell rapidly with the correct timing. In resting ventricular muscle The electrical activity of cardiac cells depends on the ionic cells, the potential inside the membrane is stable at approx- gradients across their plasma membranes and changes in per- imately 90 mV relative to the outside of the cell (see meability to selected ions brought about by the opening and phase 4, Fig. This chapter describes how these an action potential occurs (see Chapter 3). First, there is a ionic gradients and changes in membrane permeability result rapid depolarization from 90 mV to 20 mV (phase 0). Next, rapid repolarization (phase 3) returns the membrane potential to its resting THE IONIC BASIS OF CARDIAC ELECTRICAL value (phase 4). In contrast to ventricular cells, cells of the sinoatrial ACTIVITY: THE CARDIAC MEMBRANE POTENTIAL (SA) node and atrioventricular (AV) node exhibit a pro- The cardiac membrane potential is divided into 5 phases, gressive depolarization during phase 4 called the pace- phases 0 to 4 (Fig. When the membrane po- 219 220 PART IV BLOOD AND CARDIOVASCULAR PHYSIOLOGY A Major Channels Involved in Purkinje and +20 1 2 TABLE 13. Outward (transient) V Contributes briefly to Cardiac action potentials (mV) recorded rectifying K phase 1 by transiently FIGURE 13. K at positive Numbers 0 to 4 refer to the phases of the action potential (see text).
Although it was once believed that UVA rays were harmless generic tadacip 20mg, findings now indicate that ex- cessive exposure to these rays may inhibit the DNA repair process that follows exposure to UVB cheap tadacip 20mg free shipping. Therefore cheap tadacip 20 mg, individuals who are ex- posed solely to UVA rays in tanning salons are still in danger of basal cell carcinoma, because they will later be exposed to UVB rays of sunlight when they go outdoors. It was once thought to account for the yellow-tan skin of people of (c) (d) Asian descent, but this coloration is now known to be caused by variations in melanin. Oxygenated blood flowing through the dermis gives the skin its pinkish tones. Certain physical conditions or diseases cause symptomatic discoloration of the skin. In jaundice, the skin appears yellowish be- palms and the shallow flexion lines that can be seen on the cause of an excess of bile pigment in the bloodstream. Furrows on the fore- usually symptomatic of liver dysfunction and sometimes of liver im- head and face are acquired from continual contraction of facial maturity, as in a jaundiced newborn. Surface Patterns The science known as dermatoglyphics is concerned with the classification and identification of fingerprints. Every individ- The exposed surface of the skin has recognizable patterns that ual’s prints are unique, including those of identical twins. All other primates have ridges) are congenital patterns that are present on the finger and fingerprints, and even dogs have a characteristic “nose print” that is toe pads, as well as on the palms and soles. The designs formed used for identification in the military canine corps and in certain dog kennels. They are formed by the pull of elastic fibers within the dermis and are well established prenatally. The Dermis ridges of fingerprints function to prevent slippage when grasping objects. Because they are precise and easy to reproduce, finger- The dermis is deeper and thicker than the epidermis (see prints are customarily used for identifying individuals. Elastic and collagenous fibers within the dermis are arranged in definite patterns, producing lines of tension in the skin and providing skin tone (fig. Integumentary System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 5 Integumentary System 111 FIGURE 5. Stretch marks generally fade with time but may leave permanent markings. Innervation of the Skin The dermis of the skin has extensive innervation (nerve supply). Specialized integumentary effectors consist of smooth muscles or glands within the dermis that respond to motor impulses trans- mitted from the central nervous system to the skin by autonomic FIGURE 5. Surgical incisions Several types of sensory receptors respond to various tactile made parallel to the lines of tension heal more rapidly and create less (touch), pressure, temperature, tickle, or pain stimuli. Certain areas of the body, such as the palms, soles, lips, and external genitalia, have a Layers of the Dermis greater concentration of sensory receptors and are therefore more The dermis is composed of two layers. Chapter 15 includes a detailed discussion of stratum papillarosum (papillary layer), is in contact with the epi- the structure and function of the various sensory receptors. Papillae Blood vessels within the dermis supply nutrients to the mitoti- form the base for the friction ridges on the fingers and toes. Fibers within this layer blood vessels play an important role in regulating body tempera- are more dense and regularly arranged to form a tough, flexible ture and blood pressure. It is quite distensible, as is evident in pregnant tion responses can either shunt the blood away from the women or obese individuals, but it can be stretched too far, caus- superficial dermal arterioles or permit it to flow freely throughout ing “tearing” of the dermis. Fever or shock can be detected by the color and leaves a white streak called a stretch mark, or linea albicans temperature of the skin. Lineae albicantes are frequently found on the sodilation of dermal blood vessels. It is important to maintain good blood circulation in people It is the strong, resilient reticular layer of domestic mammals who are bedridden to prevent bedsores, or decubitus (de- that is used in making leather and suede. When a person lies in one position for an ex- process, the hide of an animal is treated with various chemicals that tended period, the dermal blood flow is restricted where the body cause the epidermis with its hair and the papillary layer of the dermis presses against the bed. As a consequence, cells die and open to separate from the underlying reticular layer. Changing the position of the patient then softened and treated with protective chemicals before being cut frequently and periodically massaging the skin to stimulate blood and assembled into consumer goods.
The time purchase 20 mg tadacip fast delivery, brain cheap tadacip 20mg with amex, or disconnecting the affected por- place tadacip 20 mg fast delivery, and social circumstances under tion from the rest of the brain. The amount If individuals experience a seizure in pub- of disability experienced, if any, after this lic, they risk feelings of embarrassment type of surgery depends on individual cir- and onlookers’ potential misperception of cumstances. Alcohol can lower the seizure threshold At times, even when seizures are adequate- and therefore precipitate seizures. Alcohol ly controlled, anxiety over the possibility and antiepileptic medications may also of having a seizure or other psychosocial interact and cause untoward effects. Con- dysfunction may be the most disabling sequently, individuals with epilepsy should factor associated with the condition. A medical ment and emotional development depend identiﬁcation bracelet should be worn by on when the diagnosis of epilepsy is made individuals with epilepsy at all times. When epilepsy is diagnosed in child- with epilepsy depends on the type of hood, parental feelings of fear, anxiety, seizure, the underlying cause, the admin- guilt, overprotectiveness, or mourning istration of appropriate treatment, and the can affect not only the child’s ability to individual’s willingness and ability to fol- accept his or her disability but also his or low the prescribed treatment regimen. Children may learn als with epilepsy can live active, produc- to use their condition as an excuse for in- tive lives. When medical intervention can greatly improve they are teenagers, concerns related to the ability to control seizures and enhance whether they will drive a car, participate in the general quality of life for the individ- sports, or engage in dating may cause addi- ual with epilepsy. Diagnosis of epilepsy in adulthood can Psychosocial Issues in Epilepsy also disrupt interpersonal and family rela- tionships. The impact on individuals’ Individuals with epilepsy may face social identity may be threatened, so that many psychological and psychosocial they go to great lengths to conceal their challenges. They must learn to deal with disability in order to avoid potential the uncertainty of whether and when rejection. No matter how lepsy may be fearful of observing a seizure Conditions Affecting the Brain 65 or may be concerned that the disorder is out a disability because of anticipated hereditary. Because of anxiety and misin- rejection due to real or perceived public formation, they may be unwilling to learn attitudes. Inability to drive can limit social Sexual activity, in most cases, need not interaction, educational experiences, and be affected by epilepsy (Frazer & Gumnit, employment opportunities. Although some medications used stances, individuals with epilepsy can to treat seizures may have some effect on drive without signiﬁcant risk of accident libido, most do not. Psychological issues if their seizures are controlled with med- of low self-esteem or poorly developed ication. Individuals may be reluctant to were restricted from driving motor vehi- form intimate relationships because of the cles because of concerns for public safety fear of having a seizure. Although today be necessary to help them overcome this most states permit individuals with epilep- fear so that appropriate intimate relation- sy to obtain driver’s licenses, the length of ships can be established. State laws do not always take into ing a seizure, there are no outward signs account individual differences; some make of disability. Although considerable effort blanket rules that apply to all individuals has been devoted to educate the public with epilepsy regardless of their personal about the condition, misinformation and circumstances. In some cultures, historical with epilepsy should always consult their misconceptions about epilepsy have physician about alcohol consumption, es- linked it to demonic possession and insan- pecially in regard to taking alcohol when ity. In other instances people with epilep- they are also taking anticonvulsant med- sy were not permitted to participate in ication; however, each individual situation various events because of their diagnosis. Attitudes have changed in recent years as Sports activities are also an important the result of public education programs, means of socializing as well as helping in- improved placement of individuals with dividuals build self-conﬁdence and self- epilepsy into the world of work, and in- esteem. In some situations, restrictions on creased ability to control seizures. In many participation in various activities are placed instances, however, individuals with on individuals with epilepsy even though epilepsy may still experience unjust re- no basis for limiting the activities exists. The stigma be precipitated by fatigue or other sports- and shame associated with epilepsy may related circumstances, others may have a cause individuals and/or their family to reduced incidence of seizures with exercise. Indi- Consequently, authorities should consider viduals may try to pass as someone with- the individual’s speciﬁc circumstances 66 CHAPTER 2 CONDITIONS OF THE NERVOUS SYSTEM: PART I rather than issuing blanket restrictions; reducing stress are other self-management each case should be considered individu- issues individuals with epilepsy must ally.
Respiratory System © The McGraw−Hill Anatomy cheap 20 mg tadacip amex, Sixth Edition Body Companies generic tadacip 20mg otc, 2001 Chapter 17 Respiratory System 633 Essay Questions 8 cheap tadacip 20mg. Why is warming, moistening, and filtering some of the clinical conditions that could maneuver based? When would mouth-to- the air so important for a healthy, involve this organ. Explain the structural and functional compartmentalization of the thoracic revive a person? Explain the sequence of pulmonary percussing (tapping) a patient’s chest can 3. Discuss the mechanisms of tell a physician a great deal about the pulmonary alveoli rather than bronchial inspiration and expiration. How are air condition of the organs within the trees considered the functional units of pressures related to ventilation? What is meant by a rhythmicity emphysema would sound in comparison hilum, apex, costal surface, fissure, lobe, respiratory area? What kind of sound lobule, pulmonary ligament, and bronchial and pneumotaxic areas related to the would be produced by a collapsed lung, or segment. Why do premature infants often require thoracic cavity with respect to the heart. Critical-Thinking Questions respiratory assistance (a mechanical Identify the various thoracic serous 1. Identify two places in the respiratory ventilator) to keep their lungs inflated? List the kinds of epithelial tissues found capillary networks are found. What is the mucus to build up and paralyzes the cilia within the respiratory system and describe function of each of these areas and why that line the respiratory tract. What protective devices of the respiratory the treatment of certain clinical system guard against pollutants, the conditions? Digestive System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 Digestive System 18 Introduction to the Digestive System 635 Serous Membranes and Tunics of the Gastrointestinal Tract 636 Mouth, Pharynx, and Associated Structures 640 Esophagus and Stomach 648 Small Intestine 652 Large Intestine 656 Liver, Gallbladder, and Pancreas 660 Developmental Exposition: The Digestive System 665 CLINICAL CONSIDERATIONS 669 Clinical Case Study Answer 671 Important Clinical Terminology 672 Chapter Summary 673 Review Activities 674 Clinical Case Study A 25-year-old male construction worker was admitted to the emergency room after suffering a blow to the upper abdomen from a swinging beam. Initial assessment was significant for marked tenderness in the right upper quadrant of the abdomen and for vital signs and examination findings consistent with mild hemorrhagic shock. Intravenous fluids were administered, causing stabilization of vital signs. Peritoneal lavage (see chapter 2, Clinical Case Study) was likewise negative for blood. A CT scan demonstrated a significant hematoma (collection of blood) deep within the substance of the liver (see arrow on CT scan), as well as a notable amount of blood in the small intestine. Initial exploration revealed no trauma to the stomach or small intestine. Explain anatomically how the blood found its way into the small intestine, noting each step of its path. Given that the hepatic arterial system and hepatic venous system are possible sources of the bleeding, is there another system of blood vessels relative to the liver that could also be a source of hemorrhage? FIGURE: Positioned in the upper right quadrant of the abdominal cavity, the liver is Hint: As you study the digestive system, pay close attention to the location of each accessory the largest visceral organ. Its size and density digestive organ and note how each connects to the lumen of the gastrointestinal (GI) tract. Digestive System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 Chapter 18 Digestive System 635 INTRODUCTION TO THE DIGESTIVE SYSTEM The organs of the digestive system are specialized for the diges- tion and absorption of food. The digestive system consists of a tubular gastrointestinal tract and accessory digestive organs. Objective 1 Describe the activities of the digestive system and distinguish between digestion and absorption. Objective 2 Identify the major structures and regions of the digestive system.
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