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Craft, Gordon: Understanding Pathophysiology 4e

Australia and New Zealand edition Answer Guide

Chapter 1: Introduction to Clinical Science

Focus on Learning Questions Page 7 1.Describe the term pathophysiology and define the following commonly used related terms: signs, symptoms, localised, systemic, disorder, disease, acute, chronic, insidious, incidence, prevalence, morbidity, comorbidity and mortality.Pathophysiology is defined as the study of changes to normal body function during disease processes.Signs: these are objective measurements of body processes that may give evidence of a disease process; for example, blood pressure measurement.Symptoms: a subjective indication of a disease process that is only experienced by the patient and cannot be measured; for example, pain or nausea.Localised: a sign or symptom that is restricted to a particular area of the body; for example, chest pain.Systemic: a sign or symptom that is experienced by the whole body; for example, fatigue.Disorder: a disturbance of normal function within the body; for example, hypertension.Disease: the characteristic or distinguishing features associated with a particular pathological condition. For example, coronary heart disease can result in radiating pain down the left arm, which is an indication of a blocked coronary artery that causes decreased blood supply and oxygen to the heart.

Acute: develops rapidly and lasts a short time.

Chronic: develops gradually and lasts for a long time.

Insidious: onset of disease that is gradual and does not display any signs or symptoms until the disease has significantly progressed.Incidence: the number of new cases of a disease that have been confirmed, usually within a 1-year period.Prevalence: total number of people within a population who are affected by a disease at a particular time.Morbidity: proportion of people within a population who are affected by a disease compared with people without the disease; that is, rate of disease incidence.Comorbidity: presence of another disease in addition to the primary disease; that is, coexisting diseases.

Mortality: number of deaths associated with a specific disease.

2.Describe the different age groups within a population.Incidence of disease may affect one age group more than another; therefore, age groups within a population are defined as infant (< 1 year of age), child (from 1 year of age to the onset of puberty), adolescent (onset of puberty until adulthood), adult (onset of adulthood is defined as a fully matured person) and ageing (> 65 years of age).Page 11 1.Describe the anatomical position.The anatomical position is a reference position. The position is defined as a person standing upright, arms by their sides with their palms facing forwards and their thumbs facing out. Refer to Figure 1.2, p 7.

2.Describe the orientation of the three main anatomical sections.

The three main anatomical sections are the:

sagittal plane, which is a vertical plane that divides the body into a right and left transverse plan, which is a horizontal plan that divides the body into upper and lower frontal or coronal plan, which is a vertical plane that divides the body into front (ventral) and back (dorsal). Refer to Figure 1.4, p 8.

3.Provide definitions of the six pairs of terms used in anatomy.

1.Superior: towards the head; for example, the forehead is superior to the chin.

Inferior: towards the feet; for example, the knees are inferior to the hips.

2.Anterior: towards the front (ventral); for example, the heart is anterior to the spine.Posterior: towards the back (dorsal); for example, the spine is posterior to the lungs.Copyright © 2023 Elsevier Australia Case Solutions For Understanding Pathophysiology Australia and New Zealand 4e Judy Craftv, Christopher Gordon, Sue Huether, Kathryn McCance, Valentina Brashers (All Chapters, 100% Original Verified, A+ Grade) 1 / 4

2 Answer Guide 3.Medial: towards the midline; for example, the mediastinum is medial to the scapula.

Lateral: away from the midline; for example, the arm is lateral to the trunk.

4.Proximal: towards the point of attachment to the trunk; for example, the knee is proximal to the ankle.Distal: away from the point of the attachment of the trunk; for example, fingers are distal to the elbow.

5.Superficial: towards the body surface; for example, the skin is superficial to the bone.

Deep: away from the body surface; for example, the heart is deep to the skin.

6.Central: towards the body, head and trunk; for example, the central nervous system.Peripheral: towards the hands and feet; for example, the peripheral nervous system.Refer to Figure 1.5, p. 9.

4.List the components of the body cavities.The central part of the body (which is defined as the trunk) can be divided into the dorsal (back) and the ventral (front) cavity and these cavities can be further subdivided. The dorsal cavity contains the central nervous system (which is subdivided into the cranial cavity containing the skull and brain) and the spinal cavity (which contains the spinal cord).The ventral cavity contains most of the body’s internal organs and is further subdivided into the thoracic cavity and the abdominopelvic cavity. The former contains the heart, lungs, trachea and oesophagus, and is further subdivided into the mediastinum, which is located centrally, and the pleural cavities, which are located peripherally. The abdominopelvic cavity is further subdivided into the abdominal cavity (containing the stomach, intestines, pancreas, gallbladder, spleen, kidneys and adrenal glands) and the pelvic cavity (the reproductive organs and urinary bladder).

5.Provide simple definitions for some commonly used anatomical prefixes and suffixes used in health science.Refer to Table 1.1, p. 10 for common prefixes and Table 1.2, p. 11 for common suffixes. The more common

examples of prefixes and suffixes include:

Prefixes cardio-heart endo-inner hyper-excess myo- muscl e nephro - kidney pulm-lung Suffixes -aemia in the blood -ectomy cutting out -itis inflammatio n -oma tumour Page 12 1.Describe the hierarchy of the human body, starting at the smallest level.The hierarchy of the human body categorises the smallest to the largest functional level in the body.Chemistry: the smallest functional level in the body where atoms combine to form molecules that in turn combine to form cell structures that go on to form whole cells.Cells: vary in size and shape and can have some common functions. Similar cells associate together to perform specific functions and make up tissues.

Tissues: groups of similar cells that perform similar functions.

Organs: groups of tissue that join together to perform specific and complex functions.Organ systems: groups of organs that join together to perform specific and complex functions.Human body: organ systems function collectively to achieve a well-functioning and healthy body.

2.Briefly describe the anatomy and physiology of each body system.Copyright © 2023 Elsevier Australia 2 / 4

3 Answer Guide The nervous system is the fast-acting control system of the body responsible for sending, receiving and processing nerve impulses. It is made up of the brain, spinal cord and nerves. The nervous system responds to internal and external stimuli, stimulates muscle contraction and regulates all body processes as well as personality, memory and emotion.The endocrine system is responsible for the production and secretion of hormones that regulate growth, reproduction and metabolism in the body. The endocrine system is made up of organs, glands and cells.The immune system provides the main defence against pathogens, including bacteria and viruses, and against cancer cells. It is made up of cells such as white blood cells found in the blood and tissues such as lymphoid tissue that all coordinate to defend the body.The integumentary system forms the external coverings of the body and is made up of skin and mucous membranes. It protects the body from external injury as well as being responsible for vitamin D production and aids in the regulation of body temperature.The haematological system transports nutrients and wastes via the bloodstream and also works closely with the immune system to protect the body against disease and foreign pathogens. It is made up of blood and bone marrow and is also responsible for the production of all cells found in the bloodstream.The musculoskeletal system protects and supports the body’s organs as well as allowing the body to move. It is made up of muscles and bones.The cardiovascular system pumps blood around the body, carrying nutrients and wastes. It is made up of the heart and blood vessels.The respiratory system oxygenates and removes carbon dioxide from the blood and allows speech to occur. It is made up of the respiratory tract (trachea) and the lungs.The digestive system breaks down food into absorbable material that enters the blood and supplies nutrients to the body. It is made up of the mouth, oesophagus, stomach, intestines, liver, gallbladder and pancreas.The urinary system removes nitrogenous wastes from the body as well as regulating water, electrolytes and acid–base balance in the body. It is made up of the kidneys, ureters, urinary bladder and urethra.The reproductive system is involved in the production of offspring. In males, it is made up of the testes, prostate gland, ductus deferens and the penis. In females, it is made up of ovaries, uterine tube, uterus, vagina and mammary glands.It is important to note that the body systems work in cooperation to achieve their complex functions.Page 16 1.List the main elements and electrolytes of the body.An element is a structure that cannot be broken down further. There are four main elements in the human

body: carbon (C), hydrogen (H), oxygen (O) and nitrogen (N).

Elements in the human body can either have an electrical charge (ion) or not have an electrical charge (inert). Ions are extremely important in the human body and can be positively charged (cation, +) or negatively charged (anion, –).Electrolytes are substances that have the ability to conduct electricity in water. These electrolytes can be detected in body fluids (e.g. blood and urine) and can give indications of imbalances in the body.Electrolytes are measured in millimoles per litre (mmol/L). Main examples include sodium, potassium, calcium and chloride.Refer to Table 1.4, p. 13.

2.List common examples of molecules and compounds of the body.Oxygen is a common molecule found in the human body. Water, carbon dioxide, glucose and sodium bicarbonate are examples of common compounds.

3.Define the terms hydrophilic and hydrophobic.Substances that mix well in water are called hydrophilic (hydro – water; philic – loving).Substances that do not mix well in water are called hydrophobic (hydro – water; phobic – hating).

4.Compare acid and alkaline substances. Provide the pH levels that define acidosis and alkalosis.Acids are substances that contain an H + ion and release the H + when mixed in water; for example, hydrochloric acid (HCl). Alkaline substances take up the H + ion released by an acid; for example, bicarbonate (HCO3 – ).To reflect the acidity or alkalinity of a substance, a pH scale is used. pH 0 is the strongest acid, pH 7 is neutral and pH 14 is the strongest base (refer to Figure 1.9, p 15). The pH levels in the blood are kept within Copyright © 2023 Elsevier Australia 3 / 4

4 Answer Guide a range of 7.35–7.45 by chemical buffers, the lungs and kidneys. A pH less than 7.35 is defined as an acidosis, whereas a pH greater than 7.45 indicates an alkalosis.

5.Briefly describe proteins, lipids and carbohydrates. Name the two nucleic acids.Proteins are large molecules formed by linking amino acids. The hierarchy of a protein is: Amino acids (smallest protein) → peptide (linked amino acids) → polypeptides (more linked amino acids) → proteins (complex 3D structures).Proteins are made up of carbon, hydrogen, oxygen and nitrogen. They contribute to many functions in the body including forming the structure of muscle and bone, and also contribute to the breakdown of food and accelerating body reactions via enzymes.Lipids are most commonly made up of glycerol and fatty acids and are classified as either fats (solid at room temperature) or oils (liquid at room temperature). Lipids consist of carbon, hydrogen and lesser amounts of oxygen. The functions of lipids include energy storage and maintaining the structural integrity of cell membranes. An example of a lipid in the body is a triglyceride.Carbohydrates are a group of molecules that include sugars and starches and contain carbon, hydrogen and oxygen. Carbohydrates can be classified according to size: the smallest carbohydrate is a monosaccharide containing one sugar (e.g. glucose). Disaccharides contain two sugars (e.g. sucrose) while polysaccharides contain many sugars (e.g. starch in potatoes). One of the main functions of carbohydrates in the body is to provide fuel via glucose.Nucleic acids form our genetic information and include DNA and RNA.Page 18 1.Describe how changes in pressure in different areas within the body cause substances to move.Gases, solids and fluids in a confined space exert a pressure on the enclosing walls. For example, oxygen molecules in a blood vessel will exert a pressure against the blood vessel wall. In this case, the wall of a blood vessel allows oxygen to pass through; therefore, the pressure of the oxygen molecules against the vessel walls will allow the oxygen to move out of the vessel into the surrounding tissue.

2.Describe how atmospheric pressure influences body processes.Atmospheric pressure is the weight of air. It is 760 mmHg at sea level and decreases as altitude increases.Atmospheric pressure exerts pressure on all cells, tissues and organs in the body; therefore, it will have a direct influence on fluid, gas and/or solid exchange in the body. In particular, atmospheric pressure is essential for the function of breathing.During inhalation the lungs expand and the volume of the lungs increases; therefore, pressure within the lungs decreases (drops from 760 mmHg to 759 mmHg) below atmospheric pressure. Because particles will move from an area of high pressure to an area of low pressure, this will facilitate movement of oxygen from the atmosphere into the lungs.Case Study – Adult Page 20 1.Have I been eating too much cholesterol in the past few weeks? Is that why this has happened? (Hint: consider whether heart disease is acute or chronic.) Eating high levels of cholesterol in your diet is a risk factor for heart disease and can lead to the increased risk of angina and heart attack. Heart disease is a chronic disease and has a slow onset and can take many years to develop; therefore, eating too much cholesterol in the past few weeks has not caused his chest pain — it is too quick an onset.

2.If cholesterol is so bad, why do I have it in my body anyway? (Hint: in later chapters, you will learn how high levels of cholesterol can lead to heart disease, but for now you can explain some general benefits of cholesterol and lipids in the body.) Everything is good in moderation, even fats in the diet. Cholesterol is a lipid that in high amounts increases the risk of atherosclerosis and heart disease. The amount of cholesterol in the diet should be minimised to decrease the risk of these conditions. However, no cholesterol in the diet is also detrimental. Cholesterol provides the main structural component of all cell membranes in the body as well as being necessary for the production of hormones.

3.They want to check my electrolytes. What are electrolytes?Copyright © 2023 Elsevier Australia

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