Exam II Flashcards
What percentage of lean body mass is water?
~60%
What fraction of TBW is extracellular?
1/3
What fraction of TBW is intracellular?
2/3
How many liters of water is TBW?
42 liters (for 70 kg person)
How is plasma fluid in the interstitial space returned to circulation?
Via the lymphatic system
What causes edema, in a mechanical sense?`
Anything that increases capillary pressure or reduces colloid pressure
What kind of edema does right-sided heart failure cause?
Systemic edema
What kind of edema does left-sided heart failure cause?
Pulmonary edema
What can cause reduced plasma osmotic (colloid) pressure?
Excessive loss or reduced synthesis of albumin
What protein is responsible for maintaining osmotic (colloid) pressure?
Albumin
What can caused reduced synthesis of albumin?
Malnutrition or hepatic disease (cirrhosis, hepatic tumors, or hepatitis)
Why does nephrotic syndrome reduce colloid pressure?
The kidneys become “leaky”, albumin is lost in the filtrate
What are the two main causes of lymphatic obstruction, and what does it result in?
Inflammatory obstruction or resection of lymphatics, leading to lymphedema
What causes peau d’orange?
Obstruction of superficial lymphatics by breast cancer tumor (seen in inflammatory breast cancer)
What happens in acute renal failure that results in increased water retention?
Increased Na+ retention
What complication of cerebral edema was discussed?
Herniation of brain through foramen magnum, leading to death
What percentage of total blood can healthy adults lose acutely?
Up to 20%, though more if loss is slow
hemorrhage (n.)
extravasation of blood due to rupture of blood vessels
petechiae (n.)
1-2mm hemorrhages in skin/mucous membranes
What is usually associated with petechiae?
Thrombocytopenia
What do you call blood enclosed within tissue?
Hematoma
purpura (n.)
3-5mm hemorrhages in skin/mucous membranes
ecchymosis (n.)
1-2cm hemorrhages in skin/mucous membranes
What differentiates bruises and ecchymoses?
Bruises are ecchymoses specifically caused by trauma
hemostasis (n.)
the process of causing bleeding to stop (opposite of hemorrhage)
What is endothelin?
An endothelial vasoconstrictor
What is primary hemostasis?
Platelet aggregation
What is secondary hemostasis?
Thrombin recruiting additional platelets
How is secondary hemostasis caused?
Tissue factor activates thrombin, which cleaves fibrinogen into fibrin, creating a fibrin mesh network; thrombin also recruits additional platelets
What is released to limit coagulation?
Tissue plasminogen activator (t-PA)
What does the Virchow Triad define?
The three predisposing factors of thrombosis
thrombosis (n.)
the formation of clot inside a blood vessel
What are the three components of the Virchow triad?
Endothelial injury, hypercoagulability, and stasis/turbulence
What is the dominant factor of the Virchow triad?
Endothelial injury
What were the three examples of non-disruptive endothelial injury?
Radiation, hypercholesterolemia, and cigarette smoke
What are the three things that stasis/turbulence do to cause thrombosis?
Disrupt the normal laminar blood flow; prevent dilution of activated clotting factors; prevent inflow of clotting factor inhibitors
What are five causes of high risk hypercoagulability?
Prolonged bed rest, myocardial infarction, tissue damage, cancer, and inflamed/prosthetic cardiac valves
What are five causes of low risk hypercoagulability?
Atrial fibrillation, cardiomyopathy, oral contraceptives, sickle cell anemia, and smoking
What is thrombus embolization?
Dislodging some or all of the thrombus to a distant site
What is phlebothrombosis?
Formation of a blood clot in venous circulation sans vein inflammation (phlebitis)
Where do venous thrombi embolize?
Towards the lungs
How are thrombi broken up naturally?
Dissolution by fibrinolytic activity
What is the main cause of pulmonary embolization?
Deep vein thrombosis (DVT) in the legs
cor pulmonale (n.)
right ventricular failure, or pulmonary heart disease
What is the main cause of systemic embolization?
Intracardiac wall thromboses
What causes most intracardiac wall thromboses?
Left ventricular infarcts
How what percent of systemic emboli occur in the brain?
10%
What are the five kinds of emboli?
Thrombus, fat, cholesterol, gas, and amniotic fluid
What is a fat embolus usually caused by?
Fracture of a long bone, especially the femur
What is a cholesterol embolus usually caused by?
Atherosclerotic debris
What causes an amniotic fluid embolism?
A tear in the placenta and rupture of uterine veins
What happens to the patient after amniotic fluid embolizes?
Immediate hypotensive shock; if survived, followed by DIC
What does DIC stand for?
Disseminated intravascular coagulation
What is the immediate cause of DIC?
Widespread fibrin thrombi
Is DIC a primary disorder?
No, it is a complication.
What is “shock”?
Cardiovascular collapse
Describe the cardiovascular collapse seen in shock.
Systemic hypoperfusion as a result of decreased cardiac output or circulating blood volume
What are the five main causes of shock?
Severe hemorrhage, extensive trauma/burns, large myocardial infarction, massive pulmonary embolism, and microbial sepsis
What are the five types of shock?
Cardiogenic, hypovolemic, anaphylactic, neurogenic, and septic
What causes 70% of septic shock deaths?
Gram-negative bacteria
What causes gram-negative bacterial sepsis?
Degradation in bacterial cell wall, releasing toxic lipopolysaccharides
What is the physiological causes of anaphylactic shock?
General release of histamine, causing hypotension
infectious disease (n.)
a disorder in which tissue damage or dysfunction is caused by a microorganism
virulent (n.)
capable of causing disease
What are the four properties that allow an organism to achieve infection?
Gain access to body; avoid multiple host defenses; accommodate to growth within human body milieu; parasitize human resources
What is the virulence of Q-fever?
Inoculum of only one organism needed for infection
What are two organisms that can penetrate intact skin?
HPV (genital warts) and T. pallidum (syphilis) can penetrate warm, moist skin
What is filariasis?
Obstruction of lymphatics by inflammation and fibrosis of lymphatics, caused by helminths
Why do women have UTIs more than men?
Shorter urethra (5-20 cm)
What is the organism that causes the plague?
Yersinia pestis
What class of organisms cause malaria?
Protozoans
What organism causes malaria?
Plasmodium vivax
Where does P. vivax attach?
Human RBCs by the Duffy blood group receptors
What causes chickenpox?
Varicella-zoster virus
What are the three main modes of disease transmission?
Direct contact, indirect contact, and vectors
What are the four types of direct contact transmission?
Respiratory aerosol, skin, sexual, and transplacental/vertical
What are the five types of indirect contact transmission?
Fomites, blood, stool, water, and soil
What is a fomite?
Inanimate object
What are the two main transmission vectors?
Arthropods and animals
What are four example arthropod vectors, and what diseases are associated?
Mosquito - malaria, yellow fever, dengue fever; Tick - Lyme disease; Louse - typhus, relapsing fever; Mite - scabies
What causes cat scratch fever?
Bartonella henselae, a gram-negative organism
What are the nine general mechanisms of bacterial pathogenesis?
Produce toxins; produce a slimy, phagocytic-resistant polysaccharide coat; free radical resistant cell wall glycolipids; produce substances that bind opsonins; invade epithelial cells; damage to organs/tissues from inflammatory response; grow in areas that are normally sterile; enter into bloodstream and multiply within tissue; consume host resources
What are bacteriophages?
Viruses that infect bacteria
What disease is caused by Mycobacterium leprae?
Leprosy
What disease is caused by Mycobacterium tuberculosis?
Tuberculosis (TB)
What organism multiplies in the normally sterile lung and causes pneumococcal pneumonia?
Streptococcus pneumoniae
What are two diseases caused by bacteriophages?
Diphtheria (Corynebacterium diphtheriae) and cholera (Vibrio cholerae)
plasmid (n.)
an extrachromosomal genetic element not necessary for genetic growth
What are three Clostridium species that secrete exotoxins?
C. perfringens, C. tetani, and C. botulinum
What are the three representative Gram-positive infections we discuss?
Staphylococcus aureus, Streptococcal infections, and Corynebacterium diphtheriae
What is the shape of C. diphtheriae, and how is it passed?
Gram-positive rod, passed by aerosols
What is diphtheria?
A tough pharyngeal membrane that can block the pharynx, and is toxic to the heart and nerves
What organism is one of the leading causes of bacterial pneumonia and meningitis?
Streptococcal pneumoniae
endocarditis (n.)
infection of the inner lining of the heart and heart valves
What is the organism and pathogenesis of tetanus?
C. tetani - secretes an exotoxin that interferes with inhibitory neurotransmitters (ie. GABA), causing violent muscle spasms
What is the organism and pathogenesis of botulism?
C. botulinum - secretes an exotoxin that blocks the release of ACh, causing paralysis
What is the general treatment for gram-positive infections?
Sensitive to penicillins, erythromycins, & cephalosporins
What disease does Rickettsia prowazekii cause?
Typhus
What disease does Rickettsia rickettsii cause?
Rocky Mountain spotted fever
Why are Rickettsia bacterias considered obligate intracellular parasites?
Cannot utilize glucose as an energy source; may need NAD+ and coenzyme A
Why are Chlamydiae bacterias considered obligate intracellular parasites?
They cannot make ATP
When and where was the last case of smallpox?
Somalia, 1977.
What are the symptoms and signs of smallpox?
Sudden onset of high fever, chills, headache, lumbar back pain, and prostration, with common nausea and vomiting; after 2-4 days, rash appears on face, extremities, trunk, and mucous membranes of mouth/eye, progressing over 2-4 weeks
What was tuberculosis called in the 18th century?
Consumption
How much of the world’s population is infected with TB?
1/3 of world pop.
What are the early symptoms of tuberculosis?
Fever, night sweats, weight loss, anorexia, and weakness
What is the prognosis of those with untreated TB?
1/3 die within one year; 1/2 die within five years
What is the cause of death in tuberculosis?
Respiratory compromise, cachexia, or other organ involvement
cachexia (n.)
malnutrition induced by chronic disease
What organism causes most human cases of TB?
Mycobacterium tuberculosis
What is the shape of M. tuberculosis?
Slender, rod-shaped bacteria
How does someone become infected with tuberculosis?
Inhalation of the “tubercle bacilli” (bacteria)
What organism causes anthrax?
Bacillus anthracis
What are the three forms of anthrax, and what is the relative incidence of each in the US?
Cutaneous (95%), inhalational (5%), and gastrointestinal (only 11 cases reported)
What is the mortality rate of inhalational anthrax?
95-100% if untreated; death within 24 hours
