C32 Chapter 5 Bodily Injury Claims Study

Bodily Injury Claims: Study 5

Heart and Other Organs

Heart and Circulatory System:

  • Heart is hollow, muscular organ
  • Located behind and slightly left of sternum
  • Specialized cardiac muscle tissue is called myocardium (myocardial tissue)
  • Heart is encased in membranous sac called pericardium
  • Heart itself is nourished by blood that sustains continuous muscular activity
  • Heart muscle is always “working” and must “rest” in brief period between contractions known as diastole
  • During pumping cycle, called systole, it contracts to squeeze blood through various chambers to rest of body
  • Heart is divided into 4 chambers:

    • 2 atria:
      • Function as reservoirs for blood
      • Separated from ventricle by valve
      • Wall of muscle called septum separates right atrium and ventricle from left
    • 2 ventricles
      • More thickly walled and muscular than any other part of heart
  • Blood provides oxygen to body cells and disposes of carbon dioxide in process known as respiration
Blood Vessels:

  • Very largest vessels (arteries and veins)
  • Smaller vessels (arterioles and venules)
  • Very smallest vessels (capillaries)
  • Capillaries are site where nutrients and oxygen of blood are exchanged for waste products which includes carbon dioxide
  • Arteries carry blood away from the heart
  • Arteries and arterioles have muscular component because they carry blood under relatively high pressures
  • Some important arteries are:
    • Aorta: main trunk artery, originates from upper end of left ventricle then curves downward along vertebral column (several other arteries branch from it so it supplies both upper and lower body)
    • Common Carotid: branches from aorta and supplies the brain
    • Pulmonary Arteries: supply the lungs (only artery that carries deoxygenated blood
    • Renal Arteries: supply kidneys
    • Iliac Arteries: supply legs
  • Arteries and arterioles always carry arterial blood away from the heart
  • Veins and venules always carry venous blood to the heart
  • Some important veins are:
    • Superior Vena Cava: collects blood from upper part of body
    • Inferior Vena Cava: collects blood from lower part of body
    • Pulmonary: veins return blood from the lung to the heart (only vein that carries oxygenated blood)
    • Iliac: veins collect blood from legs
  • Right ventricle pumps deoxygenated blood through the pulmonary arteries to lungs to be oxygenated
    • Only occasion where arterial blood is deoxygenated
  • Oxygenated blood flows back to the heart through pulmonary veins and is deposited in the left atrium
    • Only occasion where venous blood is oxygenated
  • Left ventricle pumps blood that is rich with oxygen and nutrients to organs and tissues of body through arteries
Trauma:

  • Heart:
    • Damaged coronary vessel or myocardium results in bleeding within the pericardium called cardiac temponade
    • Myocardial contusion is caused by blow to chest area that affects heart muscle
      • Can disrupt heart’s electrical conduction system responsible for regular, rhythmic contraction and relaxation
      • Diagnosed by abnormal electrocardiac pattern
      • Disturbance or abnormality of heart’s electrical conduction system is known as dysrhythmia
      • Absence of effective heart beat is known as arrhythmia
      • Treatment of myocardial contusions consists of bed rest for 3 – 4 weeks
    • Heart muscle may weaken as result of:
      • Narrowing of arteries which supply the heart
      • Conditions that affect valves separating chambers of heart and blood vessels leading to and from those chambers
    • In question of whether an emotional upset can precipitate a disruption of heart’s regular rhythmic contractions the argument is that the emotional upset served as the trigger which “caused” the individual to suffer the heart attack
    • It has not been established that emotional upset alone can cause heart attack
  • Blood Vessels:
    • As body ages a condition called arteriosclerosis may develop which causes blood vessels to thicken, harden and lose elasticity
    • Pain caused by insufficient supply of blood and oxygen to heart muscle is called angina
    • When heart must work harder to overcome resistance to flow of blood in narrowing vessels it results in higher blood pressure
    • Heart’s ability to overcome resistance has a limit, when this limit is reached the heart muscles begin to stretch
      • This condition is known as cardiac decompensation
    • Diet, heredity and hypertension are influential
    • If blood vessels which supply the brain are narrowed a sudden blockage or occlusion of one of these vessels will disrupt blood supply to brain causing stroke
    • Weakening of walls of blood vessels will cause them to dilate and form aneurysms
    • These common conditions just described are not usually caused by trauma
Blood:

  • Carries oxygen and nutrients for cellular respiration
  • Carries away by-products of respiration for elimination by various means
    • By-products are toxic to tissues of body if they accumulate
  • Two main parts of blood:
    • Plasma:
      • liquid component of blood
      • Solution into which many chemicals are dissolved
    • Cellular components:
      • Red blood cells:
        • also called erythrocytes
        • red disc-shaped cells carry oxygen to tissues of body
        • primary composed of haemoglobin
          • One of main components of haemoglobin is iron
      • White blood cells:
        • Principally involved in body’s immune system
        • Many different varieties of white blood cells in body
        • Fight disease and defend body against bacteria
      • Platelets:
        • Small bits of cellular material in blood which assist in clotting wounds
  • Cellular components of blood are manufactured in bone marrow
Blood Pressure:

  • Usually recorded by two figures:
    • Highest is systolic pressure (during contraction of heart)
    • Lowest is diastolic pressure (during relaxation of heart)
    • Difference between two pressures is called the pulse pressure
  • Short form for blood pressure is BP
  • Sphygmomanometer is used to measure blood pressure in millimeters of mercury
  • Stethoscope is used to listen to heart beat
  • When pressure is too high it is called hypertension
  • When pressure is too low it is called hypotension
  • Important to treat abnormally high blood pressure because lining of arteries and arterioles will be affected by prolonged exposure to high pressures
  • Doctors medicate where diastolic pressure is greater than 95 mm Hg (mercury)
Trauma:

  • Shock:
    • Immediate effect of massive blood loss
    • Leading cause of death among trauma victims
    • Treated by stopping blood loss, rapidly replacing lost fluids, and administering appropriate drugs to stimulate heart
    • Assuming fluid is replaced, main problem will be a reduction in number of red blood cells causing anaemia
    • Lack of haemoglobin decreases blood’s ability to carry oxygen
    • Patient may have to be treated with iron supplements
    • Transfusions of red blood cells sometimes necessary
  • Blood Clots:
    • When clot of blood forms in circulatory system it is called thrombosis
    • Loose clot in circulatory system is called embolus
    • Embolism is the blocking of a blood vessel by an embolus
    • Anticoagulants reduce most of the risk of an embolus occurring
      • Anticoagulant is medication that inhibits blood’s clotting
      • This can cause spontaneous internal haemorrhage
    • If clot is large enough to hinder or block the flow of blood through the artery or vein it will cause pain, numbness and coldness of the affected part
    • Formation of such clots in coronary arteries or heart cause heart attacks
    • When they form in brain arteries they cause strokes
    • There are also many disease processes that can produce the same result
Diagnostic Aids:

  • Electrocardiogram (ECG): measures electrical activity generated by heart. Accurately show past problems (heart attacks) and existing problems (effects of high blood pressure on the heart)
  • Echocardiogram: a specialized form of ultrasound device used to examine action of valves between the chambers of heart
  • Radionucleotides: ingested in liquid form to make heart tissue conspicuous for scanning. Pictures produced of the heart muscle in motion and thus areas of weakness and damage are revealed
  • Plethysmograph: is a device used to measure variations, in the size of a part or organ of the body, produced by changes in circulation of blood within it
Other Organs:

  • Lungs and Respiration:
    • Lungs are masses of spongy tissue which are located in the thoracic cavity (chest area) extending from behind the collarbones to the diaphragm
    • Each lung is encased in a membrane composed of two layers called pleura
    • Area between these layers (pleural cavity) is filled with fluid
    • Alveoli pulmonis are air sacs in lungs that diffuse oxygen from air into blood supply
    • Trachea (windpipe) leads to air tubes, called bronchi, within the lung
    • Epiglottis is flap that covers entrance to trachea to prevent food from entering lungs
    • External respiration is process of inspiration (inhalation) in which oxygen is received into the bloodstream via lungs, and expiration (exhalation) where carbon dioxide and vapour are expelled
    • When air is inhaled it lowers air pressure in lungs causing diaphragm to move down
    • Higher pressure outside the body forces air into lungs to equalize air pressure
    • During exhalation interior air pressure is raised to exceeding outside pressure until air rushes out causing diaphragm to move up
    • Trauma:
      • Physiology of respiration requires that negative pressure or partial vacuum exist in thoracic cavity
      • When trauma produces hole in thoracic cavity, or rib fracture penetrates lungs, there is no longer pressure differential to allow air to move in and out of chest
      • This condition is called pneumothorax and causes lung to collapse
      • Thoracic area is divided into two airtight compartments with one lung in each
      • If pneumothorax occurs the other lung functions independently to keep patient alive
      • Complications arise if lungs are lacerated or collapsed, causing shortness of breath, haemorrhage, shock, and later infection
      • Shortness of breath causing rapid shallow breathing can cause cyanosis
      • Common lung infections are pneumonia (inflammation) and empyema (accumulation of pus)
  • Abdominal Area:
    • Abdomen is encased in clear thin membrane called peritoneum wall
    • This membrane completely surrounds stomach, jejunum, ileum and transverse colon
    • Partially covers liver, uterus, and ascending and descending colons
    • Outside of peritoneum wall are kidneys, urinary bladder, pancreas, duodenum and blood vessels
    • Liver:
      • Largest glandular organ
      • Located in right upper area of abdomen
      • Soft and brown
      • It controls blood’s sugar level, breaks down blood fats, secretes bile and filters blood
      • Trauma to upper abdomen may cause tear of liver
      • Blood and bile may leak into peritoneal cavity causing peritonitis
      • Symptoms include abdominal pain, constipation, vomiting and fever
    • Pancreas:
      • Rests against small intestine behind stomach
      • Manufactures enzymes that help digest food in intestine
      • Cells scattered through the pancreas produce insulin
      • When these cells do not function properly it causes diabetes
      • Diabetes is controlled with commercial insulin
    • Kidneys:
      • Two kidneys lie in back portion of abdominal cavity on outside of peritoneum wall
      • Located on each side of spine above small of back
      • Filter waste products from blood and maintain body’s acid-alkaline balance
      • When bruised may cause bleeding in urine
    • Spleen:
      • Lies behind stomach just above left kidney
      • Function is to produce certain blood cells, destroy worn out blood cells and remove debris of disintegrating blood cells
      • Liver has similar purpose
      • Removal of spleen (spleenectomy) does not have life threatening consequences
      • Very susceptible to traumatic injury because it is quite soft
        • Because it is soft unable to suture if lacerated
    • Stomach:
      • Extremely resilient organ used to digest food
      • Esophagus (food pipe) delivers food into stomach to be broken down by acidic juices
      • Stomach and intestines form part of gastrointestinal system
      • Through digestive organs broken down food constituents are absorbed into blood stream and used as fuel for process of cellular respiration
      • Sections of stomach can be removed
      • Peptic ulcers appear as lesions in mucuous membrane of stomach or duodenum
      • New developments in medicine suggest some ulcers are caused by bacteria
    • Intestines:
      • Intestines extend from stomach to rectum
      • Small intestine connects to stomach
      • 3 main areas of small intestine:
        • Duodenum – 1st section
        • Jejunum - middle
        • Ilium – end
      • From small intestine mostly digested food passes into large intestine in area of cecum
      • Large intestine is made up of
        • Cecum
        • Ascending colon
        • Transverse colon
        • Descending colon
        • Rectum
    • Urinary Bladder:
      • Tough elastic muscular sac which stores urine
      • Located in lower abdomen in front of pelvic cavity
      • When filled with urine, it is vulnerable to rupture as result of trauma
      • Leakage into abdominal cavity results in peritonitis which requires surgical treatment
      • Perforated urinary bladder can be repaired by suturing
      • Catheter is inserted into bladder to drain bladder until it heals
    • Uterus:
      • Female organ located in pelvic cavity
      • Ovaries are buried deep within abdomen in fatty tissue
    • Trauma:
      • Certain organs are susceptible to injury because of their structure and the fact that they contain air or fluid
      • Frequency of injuries to organs in abdominal area such as stomach, bladder, kidney, spleen, intestine, urethra, liver and pancreas depends to a large extent on positioning in body, and amount of protection afforded by bone and muscle
      • First sign of bleeding in intestinal system is vomiting of blood or partially digested blood
      • Other indicators are passing of black tarry stools
      • Incision through any part of abdominal wall is called laparotomy
      • When an endoscope is used to visualize contents of abdominal cavity process is called laparoscopy
        • Often used to examine damaged organ, to diagnose the extent of damage, and repair it

Trauma and Cancer:

  • Trauma does not accelerate cancer cell production
  • Influx of white blood cells exert an inhibitory effect on cancer cells
Definitions:
Respiration: is the exchange of oxygen and waste products (ex. Carbon dioxide) between the atmosphere and the cells of the body. (Includes breathing which brings oxygen into the lungs and carries away carbon dioxide)
Myocardial Infarction: is death of the myocardium as result of interruption of blood supply to the area
Diaphragm: is the strong muscular partition between the thoracic cavity and abdominal cavity
Cyanosis: causes skin, lips and nail beds to turn bluish due to insufficient oxygen in blood
Peritonitis: is inflammation of peritoneum
Catheter: is slender, flexible tube made of rubber, metal or plastic that removes or introduces fluids from or into the body
Tracheotomy: direct surgical opening of trachea through the neck to facilitate breathing or remove secretions
Thoracotomy: is a surgical incision in chest wall

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