By Q. Vibald. University of Delaware. 2018.
I wish it had been available when I was in need generic 130mg malegra dxt overnight delivery, I am sure that you will all use it well in the pursuit of excellent clinical dermatology! Dr Mark Goodfield President of the British Association of Dermatologists 6 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors What is dermatology? Ability to examine skin purchase malegra dxt 130mg mastercard, hair buy malegra dxt 130mg free shipping, nails and mucous membranes systematically showing respect for the patient 5 malegra dxt 130mg fast delivery. Ability to record findings accurately in patient’s records Taking a dermatological history • Using the standard structure of history taking, below are the important points to consider when taking a history from a patient with a skin problem (Table 1). Taking a dermatological history Main headings Key questions Presenting complaint Nature, site and duration of problem History of presenting complaint Initial appearance and evolution of lesion* Symptoms (particularly itch and pain)* Aggravating and relieving factors Previous and current treatments (effective or not) Recent contact, stressful events, illness and travel History of sunburn and use of tanning machines* Skin type (see page 70)* Past medical history History of atopy i. General terms Terms Meaning Pruritus Itching Lesion An area of altered skin Rash An eruption Naevus A localised malformation of tissue structures Example: (Picture Source: D@nderm) Pigmented melanocytic naevus (mole) Comedone A plug in a sebaceous follicle containing altered sebum, bacteria and cellular debris; can present as either open (blackheads) or closed (whiteheads) Example: Open comedones (left) and closed comedones (right) in acne 10 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Table 4. Distribution (the pattern of spread of lesions) Terms Meaning Generalised All over the body Widespread Extensive Localised Restricted to one area of skin only Flexural Body folds i. Configuration (the pattern or shape of grouped lesions) Terms Meaning Discrete Individual lesions separated from each other Confluent Lesions merging together Linear In a line Target Concentric rings (like a dartboard) Example: Erythema multiforme Annular Like a circle or ring Example: Tinea corporis (‘ringworm’) Discoid / A coin-shaped/round lesion Nummular Example: Discoid eczema 12 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Table 6. Colour Terms Meaning Erythema Redness (due to inflammation and vasodilatation) which blanches on pressure Example: Palmar erythema Purpura Red or purple colour (due to bleeding into the skin or mucous membrane) which does not blanch on pressure – petechiae (small pinpoint macules) and ecchymoses (larger bruise-like patches) Example: Henoch-Schönlein purpura (palpable small vessel vasculitis) 13 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Hypo- Area(s) of paler skin pigmentation Example: Pityriasis versicolor (a superficial fungus infection) De- White skin due to absence of melanin pigmentation Example: Vitiligo (loss of skin melanocytes) Hyper- Darker skin which may be due to various causes (e. Morphology (the structure of a lesion) – Primary lesions Terms Meaning Macule A flat area of altered colour Example: Freckles Patch Larger flat area of altered colour or texture Example: Vascular malformation (naevus flammeus / ‘port wine stain’) Papule Solid raised lesion < 0. Morphology - Secondary lesions (lesions that evolve from primary lesions) Terms Meaning Excoriation Loss of epidermis following trauma Example: Excoriations in eczema Lichenification Well-defined roughening of skin with accentuation of skin markings Example: Lichenification due to chronic rubbing in eczema Scales Flakes of stratum corneum Example: Psoriasis (showing silvery scales) 18 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Crust Rough surface consisting of dried serum, blood, bacteria and cellular debris that has exuded through an eroded epidermis (e. Hair Terms Meaning Alopecia Loss of hair Example: Alopecia areata (well-defined patch of complete hair loss) Hirsutism Androgen-dependent hair growth in a female Example: Hirsutism Hypertrichosis Non-androgen dependent pattern of excessive hair growth (e. Nails Terms Meaning Clubbing Loss of angle between the posterior nail fold and nail plate (associations include suppurative lung disease, cyanotic heart disease, inflammatory bowel disease and idiopathic) Example: (Picture source: D@nderm) Clubbing Koilonychia Spoon-shaped depression of the nail plate (associations include iron-deficiency anaemia, congenital and idiopathic) Example: (Picture source: D@nderm) Koilonychia Onycholysis Separation of the distal end of the nail plate from nail bed (associations include trauma, psoriasis, fungal nail infection and hyperthyroidism) Example: (Picture source: D@nderm) Onycholysis Pitting Punctate depressions of the nail plate (associations include psoriasis, eczema and alopecia areata) Example: (Picture source: D@nderm) Pitting 22 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Background Knowledge • This section covers the basic knowledge of normal skin structure and function required to help understand how skin diseases occur. Ability to describe the difficulties, physical and psychological, that may be experienced by people with chronic skin disease Functions of normal skin • These include: i) Protective barrier against environmental insults ii) Temperature regulation iii) Sensation iv) Vitamin D synthesis v) Immunosurveillance vi) Appearance/cosmesis Structure of normal skin and the skin appendages • The skin is the largest organ in the human body. The skin appendages (structures formed by skin-derived cells) are hair, nails, sebaceous glands and sweat glands. The average epidermal turnover time (migration of cells from the basal cell layer to the horny layer) is about 30 days. Composition of each epidermal layer Epidermal layers Composition Stratum basale Actively dividing cells, deepest layer (Basal cell layer) Stratum spinosum Differentiating cells (Prickle cell layer) Stratum granulosum So-called because cells lose their nuclei and contain (Granular cell layer) granules of keratohyaline. Stratum corneum Layer of keratin, most superficial layer (Horny layer) • In areas of thick skin such as the sole, there is a fifth layer, stratum lucidum, beneath the stratum corneum. This occurs in 3 main phases: a) anagen (long growing phase) b) catagen (short regressing phase) c) telogen (resting/shedding phase) • Pathology of the hair may involve: a) reduced or absent melanin pigment production e. Stages of wound healing Stages of wound healing Mechanisms Haemostasis ● Vasoconstriction and platelet aggregation ● Clot formation Inflammation ● Vasodilatation ● Migration of neutrophils and macrophages ● Phagocytosis of cellular debris and invading bacteria Proliferation ● Granulation tissue formation (synthesised by fibroblasts) and angiogenesis ● Re-epithelialisation (epidermal cell proliferation and migration) Remodelling ● Collagen fibre re-organisation ● Scar maturation 27 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Emergency Dermatology • These are rapidly progressive skin conditions and some are potentially life- threatening. Ability to recognise and describe these skin reactions: - urticaria - erythema nodosum - erythema multiforme 2. Ability to recognise these emergency presentations, discuss the causes, potential complications and provide first contact care in these emergencies: - anaphylaxis and angioedema - toxic epidermal necrolysis - Stevens-Johnson syndrome - acute meningococcaemia - erythroderma - eczema herpeticum - necrotising fasciitis 28 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Urticaria, Angioedema and Anaphylaxis Causes ● Idiopathic, food (e. A large number of inflammatory mediators (including prostaglandins, leukotrienes, and chemotactic factors) play a role but histamine derived from skin mast cells appears to be the major mediator. Local mediator release from mast cells can be induced by immunological or non-immunological mechanisms. Stevens-Johnson syndrome may have features overlapping with toxic epidermal necrolysis including a prodromal illness. Herpes zoster (shingles) infection due to varicella-zoster virus affecting the distribution of the ophthalmic division of the fifth cranial (trigeminal) nerve Note: Examination for eye involvement is important Learning outcomes: Ability to describe the presentation, investigation and management of: - cellulitis and erysipelas - staphylococcal scalded skin syndrome - superficial fungal infections 36 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Erysipelas and Cellulitis Description ● Spreading bacterial infection of the skin ● Cellulitis involves the deep subcutaneous tissue ● Erysipelas is an acute superficial form of cellulitis and involves the dermis and upper subcutaneous tissue Causes ● Streptococcus pyogenes and Staphylococcus aureus ● Risk factors include immunosuppression, wounds, leg ulcers, toeweb intertrigo, and minor skin injury Presentation ● Most common in the lower limbs ● Local signs of inflammation – swelling (tumor), erythema (rubor), warmth (calor), pain (dolor); may be associated with lymphangitis ● Systemically unwell with fever, malaise or rigors, particularly with erysipelas ● Erysipelas is distinguished from cellulitis by a well-defined, red raised border Management ● Antibiotics (e. Ability to recognise: - Bullous pemphigoid - Pemphigus vulgaris 52 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Bullous pemphigoid Description ● A blistering skin disorder which usually affects the elderly Cause ● Autoantibodies against antigens between the epidermis and dermis causing a sub-epidermal split in the skin Presentation ● Tense, fluid-filled blisters on an erythematous base ● Lesions are often itchy ● May be preceded by a non-specific itchy rash ● Usually affects the trunk and limbs (mucosal involvement less common) Management ● General measures – wound dressings where required, monitor for signs of infection ● Topical therapies for localised disease - topical steroids ● Oral therapies for widespread disease – oral steroids, combination of oral tetracycline and nicotinamide, immunosuppressive agents (e. Learning objectives: Ability to formulate a differential diagnosis, describe the investigation and discuss the management in patients with: - chronic leg ulcers - itchy eruption - a changing pigmented lesion - purpuric eruption - a red swollen leg 55 Dermatology: Handbook for medical students & junior doctors 56 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 57 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 58 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 59 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 60 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 61 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 62 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 63 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors 64 British Association of Dermatologists Dermatology: Handbook for medical students & junior doctors Management Management and therapeutics • Treatment modalities for skin disease can be broadly categorised into medical therapy (topical and systemic treatments) and physical therapy (e.
Criteria Yes No N ⁄ A Initials Details Vitalsignsstable Orientatedtotime discount malegra dxt 130 mg with visa,place&person Passedurine(ifapplicable) Abletodress&walk(whereappropriate) Oralﬂuidstolerated(ifapplicable) Minimalpain Minimalbleeding Minimalnausea ⁄ vomiting Cannularemoved Responsibleescortpresent Hascarerfor24-hpostop Written&verbalpostopinstructions Knowswhotocontactinanemergency Followupappointment Removalofsuturesrequired? Produced in collaboration with the Ethiopia Public Health Training Initiative discount malegra dxt 130 mg with mastercard, The Carter Center discount malegra dxt 130mg with amex, the Ethiopia Ministry of Health cheap 130mg malegra dxt with mastercard, and the Ethiopia Ministry of Education. Important Guidelines for Printing and Photocopying Limited permission is granted free of charge to print or photocopy all pages of this publication for educational, not-for-profit use by health care workers, students or faculty. All copies must retain all author credits and copyright notices included in the original document. Under no circumstances is it permissible to sell or distribute on a commercial basis, or to claim authorship of, copies of material reproduced from this publication. Except as expressly provided above, no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the author or authors. This material is intended for educational use only by practicing health care workers or students and faculty in a health care field. An important development in this discipline is mandatory because of the expansion of different industrial, medical, environmental, animal and plant noxious substances. So toxicology has got special attention to the deleterious effects of chemicals and physical agents on all living systems. Toxicology can be an independent descriptive, empiric discipline to the fact of difficulty in diagnosis, controversial management and unknown end points. Many lethal exposures deserve early diagnosis & management before the confirmatory evidences. This lecture note on toxicology is primarily inspired for undergraduate laboratory technology students who participate in the care of poisoned patients. However, other health professionals whose carriers involve related aspects can find it relevant. The outline format of the lecture note allows for particular rapid review of essential information. The first two chapters of this lecture note focus on the introduction, basic concepts of toxicology and general approach to poisoned patients. The third, fourth & fifth chapters are concerning the basic toxicological testing methods, which planned specifically as a subject matter to the i students to improve the quality of the diagnosis in poisoned patients. The Chapters open with a guiding list of objectives & end up with questions to challenge the readers about the subject matter. Most of the sections have an introduction part designed to provide the background information of the materials to be covered. Primary references to particular methods have not been given, in order to simplify presentation & also because many tests have been modified over the years, so that reference back to the original paper could cause confusion. For further information &supplementations, readers are supposed to revise the references. We like to extend our thanks to Hawassa university pharmacology & medical laboratory department heads Dr. Sintayehu Abebe & Ato Dawit Yidegu respectively, for their encouragement during the preparation. The valuable comments made during intra &inter-institutional review meetings by Hawassa & different university lecturers in the department of pharmacology &medical laboratory strengthened the lecture note. We like to thank also our secretory W/o Tadelech Beriso for her dedication in writing the drafts. At last our gratitude also extends to those who provided support &comments on various drafts during the preparation. Average life expectancy rose, due to better control of epidemics and infectious diseases. However, increased industrialization and agricultural development were the chief cause of pollution that had profound influences on our lives. Man, the other animals, & the plants in the modern world are increasingly being exposed to chemicals of an enormous variety. Nearly everyone is at risk of toxic exposures to hazardous substances in the ambient environment. In recent years, awareness of the problem of human & animal exposure to potentially toxic chemicals in our environment 1 Toxicology has grown. So toxicology has a very important role to play in modern society & consequently it is now growing rapidly as a new subject.
These range from stress urinary incontinence (a spurt-like leakage of urine from the urethra associated with an increase in abdominal pressure such as occurs with sneezing quality 130 mg malegra dxt, coughing proven 130mg malegra dxt, etc cheap 130mg malegra dxt free shipping. Non-operative treatment of pelvic relaxation is used when symptoms are minimal or when surgery cannot be performed because of infrmity and frailty cheap malegra dxt 130 mg otc. Such conservative treatment options include change of activities, management of constipation and other circumstances that increase abdominal pressure, pelvic foor exercises, hormone replacement, and pessaries. Pessaries are mechanical devices that are inserted into the vagina to act as a “strut” to help provide pelvic support. The side effects of pessaries are vaginitis (vaginal infection and discharge), extrusion (the inability to retain the pessary in proper position), and the “unmasking” of stress incontinence. You may wonder why a urologist is interested in female pelvic relaxation, since for many years urology was traditionally considered to be a male feld. In the late 1970’s, female urology emerged as a specialty branch of urology much as pediatric urology had done previously. Raz, a world-renowned physician and surgeon, developed the feld of female urology into a comprehensive surgical discipline. In addition to writing the textbook Atlas of Transvaginal Surgery and editing the textbook Female Urology, Dr. I was fortunate to be selected for one of these positions and after the completion of my urology residency at the University of Pennsylvania School of Medicine, spent the years 1987–1988 operating with Dr. Obviously, prolapse is an exclusively female feld, but incontinence and voiding dysfunction encompass both females and males. My practice is, in fact, almost equally divided between women and men, and I fnd that I enjoy this balance. Similarly, the gynecologist’s role in female pelvic relaxation was focused on prolapse of the bladder, uterus, and rectum, but ignored the urethral prolapse that is often responsible for stress urinary incontinence. Thus there was a division of labor, a “territoriality” within the realm of Figure 1 female pelvic surgery, as illustrated in this cartoon demonstrating the roles of the urologist, gynecologist, as well as the colon/rectal surgeon. Raz espoused the concept of a pelvic surgeon, one capable of dealing with any and all aspects of female pelvic relaxation, with a thorough knowledge of pelvic anatomy and plastic surgical reconstructive principles. Raz established became to train accomplished pelvic surgeons who could then obtain academic positions at University medical centers throughout the United States, the appropriate venue for further dissemination of the art and science of female urology and pelvic reconstructive surgery to medical students and residents in training. Thus, at Hackensack University Medical Center, one of my roles is to instruct urology residents and medical students from the University of Medicine and Dentistry of New Jersey in the principles and surgical techniques of Dr. Female pelvic reconstructive surgery incorporates principles of both urological, gynecological, and plastic surgery. A pelvic reconstruction for pelvic prolapse is not dissimilar to cosmetic facial surgical procedures performed by plastic surgeons for aging and sagging eyelids and jowels. Both pelvic reconstructive and plastic facial reconstructive surgery require some degree of creativity and artistic talent in addition to the requisite scientifc knowledge of anatomy and surgical principles. I personally fnd female reconstructive surgery to be particularly gratifying because of both the instant ability to assess the results before leaving the operating room as well as the great potential to improve the lifestyle and function of the person suffering with prolapse. Unlike facial cosmetic surgery, pelvic reconstruction, in addition to improving - 3 - cosmetic appearance, will result in functional improvement in terms of alleviation of incontinence, voiding dysfunction, sexual dysfunction, bowel dysfunction, and other symptoms associated with pelvic prolapse. Anatomy of The Female Pelvis A basic knowledge of pelvic anatomy will allow you to understand why prolapse occurs and how it can be corrected. The bony pelvis is the framework to which the support structures Uterus Bladder Sacrum Pubic Bone Rectum Urethra Vagina Levator Ani Figure 2 of the pelvis are attached. The pelvis is defned as the cup-shaped ring of bone at the lower end of the trunk, formed by the hip bone (comprised of the pubic bone, ilium, and ischium) on either side and in front, and the sacrum and coccyx in back. Located within this “scaffolding” are the urinary structures (bladder, urethra), genital structures (vagina, cervix, uterus, fallopian tubes, ovaries), and the rectum. The failure of the pelvic support system allows for descent of one or more of the pelvic organs into the potential space of the vagina, and at its most severe degree, outside the vaginal opening. The tendinous arc is a very important anatomic support in the pelvis because it forms the common insertion point for a set of pelvic muscles including the levator ani muscles. The levator ani muscle extends from the left tendinous Abdominal View of The Bladder arc to the right tendinous arc, creating a hammock-like structure. The “pelvic leaf” fuses with the “vaginal leaf” to insert into the tendinous Endopelvic Fascia Overlying Levators arc. Figure 5 The vaginal leaf is called the peri- urethral fascia (at the level of the urethra), and the perivesical fascia (at the level of the bladder).
Cocaine vaccine for the treatment of cocaine dependence in methadone-maintained patients: A randomized order 130 mg malegra dxt visa, double-blind 130 mg malegra dxt mastercard, placebo-controlled efficacy trial malegra dxt 130mg low cost. Implementing a screening and brief intervention for high-risk drinking in university-based health and mental health care settings: Reductions in alcohol use and correlates of success cheap malegra dxt 130mg without a prescription. A proof-of- concept randomized controlled study of gabapentin: Effects on cannabis use, withdrawal and executive function deficits in cannabis-dependent adults. Effects of oral acamprosate on abstinence in patients with alcohol dependence in a double-blind, placebo-controlled trial: The role of patient motivation. The relationship between discrimination and substance use disorders among lesbian, gay, and bisexual adults in the United States. Motives for nonmedical use of prescription opioids among high school seniors in the United States: Self-treatment and beyond. Reliability and validity of screening instruments for drug and alcohol abuse in adults seeking evaluation for attention-deficit/hyperactivity disorder. Direct care workers in the National Drug Abuse Treatment Clinical Trials Network: Characteristics, opinions, and beliefs. The relative contribution of outcome domains in the total economic benefit of addiction interventions: A review of first findings. Symptoms and sleep patterns during inpatient treatment of methamphetamine withdrawal: A comparison of mirtazapine and modafinil with treatment as usual. Alcoholics Anonymous involvement and positive alcohol-related outcomes: Cause, consequence, or just a correlate? Crossing the quality chasm: Autonomous physician extenders will necessitate a shift to enterprise liability coverage for health care delivery. Drug dependence, a chronic medical illness: Implications for treatment, insurance, and outcomes evaluation. Reconsidering the evaluation of addiction treatment: From retrospective follow-up to concurrent recovery monitoring. Telephonic screening and brief intervention for alcohol misuse among workers contacting the employee assistance program: A feasibility study. Alcohol screening and brief intervention in the workplace: Opportunities for early identification and intervention. A comparison of methadone, buprenorphine and alpha(2) adrenergic agonists for opioid detoxification: A mixed treatment comparison meta-analysis. Environmental regulation of the development of mesolimbic dopamine systems: A neurobiological mechanism for vulnerability to drug abuse? Effects of alcohol and combined marijuana and alcohol use during adolescence on hippocampal volume and asymmetry. Quality measurement and accountability for substance abuse and mental health services in managed care organizations. Weight status continuity and change from adolescence to young adulthood: Examining disease and health risk conditions. Prejudice, social stress, and mental health in lesbian, gay, and bisexual populations: Conceptual issues and research evidence. Case-control study of attention- deficit hyperactivity disorder and maternal smoking, alcohol use and drug use during pregnancy. The association between exposure to environmental tobacco smoke and breast cancer: A review by the California Environmental Protection Agency. Motivational enhancement therapy manual: A clinical research guide for therapists treating individuals with alcohol abuse and dependence (Vols. Longitudinal assessment of mental health problems among active and reserve component soldiers returning from the Iraq war. Screening and counseling for adolescent alcohol use among primary care physicians in the United States. Dual diagnosis patients in substance abuse treatment: Relationship of general coping and substance-specific coping to 1-year outcomes.
S occurs prior to S and the collective sounds S purchase 130 mg malegra dxt amex, S cheap malegra dxt 130mg on-line, and4 1 4 1 S are referred to by some cardiologists as the “Tennessee gallop buy generic malegra dxt 130mg on line,” because of their similarity to the sound produced by a2 galloping horse with a different gait quality malegra dxt 130mg. The term murmur is used to describe an unusual sound coming from the heart that is caused by the turbulent flow of blood. Murmurs are graded on a scale of 1 to 6, with 1 being the most common, the most difficult sound to detect, and the least serious. Phonocardiograms or auscultograms can be used to record both normal and abnormal sounds using specialized electronic stethoscopes. Inhalation increases blood flow into the right side of the heart and may increase the amplitude of right-sided heart murmurs. Expiration partially restricts blood flow into the left side of the heart and may amplify left-sided heart murmurs. Bradycardia is the condition in which resting rate drops below 60 bpm, and tachycardia is the condition in which the resting rate is above 100 bpm. If the patient is not exhibiting other symptoms, such as weakness, fatigue, dizziness, fainting, chest discomfort, palpitations, or respiratory distress, bradycardia is not considered clinically significant. However, if any of these symptoms are present, they may indicate that the heart is not providing sufficient oxygenated blood to the tissues. Treatment relies upon establishing the underlying cause of the disorder and may necessitate supplemental oxygen. Tachycardia is not normal in a resting patient but may be detected in pregnant women or individuals experiencing extreme stress. In the latter case, it would likely be triggered by stimulation from the limbic system or disorders of the autonomic nervous system. Some individuals may remain asymptomatic, but when present, symptoms may include dizziness, shortness of breath, lightheadedness, rapid pulse, heart palpations, chest pain, or fainting (syncope). Treatment depends upon the underlying cause but may include medications, implantable cardioverter defibrillators, ablation, or surgery. The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioaccelerator nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve, cranial nerve X. Both sympathetic and parasympathetic stimulations flow through a paired complex network of nerve fibers known as the 868 Chapter 19 | The Cardiovascular System: The Heart cardiac plexus near the base of the heart. It opens chemical- or ligand-gated sodium and calcium ion channels, allowing an influx of positively charged ions. They innervate the heart via sympathetic cardiac nerves that increase cardiac activity and vagus (parasympathetic) nerves that slow cardiac activity. Parasympathetic stimulation originates from the cardioinhibitory region with impulses traveling via the vagus nerve (cranial nerve X). To speed up, one need merely remove one’s foot from the break and let the engine This OpenStax book is available for free at http://cnx. Input to the Cardiovascular Center The cardiovascular center receives input from a series of visceral receptors with impulses traveling through visceral sensory fibers within the vagus and sympathetic nerves via the cardiac plexus. Among these receptors are various proprioreceptors, baroreceptors, and chemoreceptors, plus stimuli from the limbic system. Collectively, these inputs normally enable the cardiovascular centers to regulate heart function precisely, a process known as cardiac reflexes. Increased physical activity results in increased rates of firing by various proprioreceptors located in muscles, joint capsules, and tendons. The cardiac centers monitor these increased rates of firing, and suppress parasympathetic stimulation and increase sympathetic stimulation as needed in order to increase blood flow. Similarly, baroreceptors are stretch receptors located in the aortic sinus, carotid bodies, the venae cavae, and other locations, including pulmonary vessels and the right side of the heart itself. Rates of firing from the baroreceptors represent blood pressure, level of physical activity, and the relative distribution of blood. The cardiac centers monitor baroreceptor firing to maintain cardiac homeostasis, a mechanism called the baroreceptor reflex. With increased pressure and stretch, the rate of baroreceptor firing increases, and the cardiac centers decrease sympathetic stimulation and increase parasympathetic 870 Chapter 19 | The Cardiovascular System: The Heart stimulation. As pressure and stretch decrease, the rate of baroreceptor firing decreases, and the cardiac centers increase sympathetic stimulation and decrease parasympathetic stimulation.
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