Cardiovascular & Lymphatic Flashcards
What does the cardiovascular system do?
Circulates blood through the body tissues. Delivers substances to and removes substances from cells.
What is the flow in the lymphatic system?
Plasma leaves blood capillaries to become interstitial fluid. Lymph capillaries transport interstitial fluid to lymph vessels and nodes, picking up microorganisms and infectious agents.
Does interstitial fluid contain cells?
No. It should not.
What do lymph nodes contain?
Fixed macrophages, B cells and T cells.
Buboes
Swollen lymph nodes
Septicemia
acute illness due to presence of pathogens or their toxins in the blood
Sepsis
systemic inflammatory response syndrome SIRS
Lymphangitis
Inflamed lymph vessels
Severe sepsis
Decreased blood pressure and dysfunction of at least one organ
Septic shock
Sepsis and uncontrollable decreased blood pressure
Why do blood vessels dilate during sepsis?
1) Endotoxin and exotoxins trigger vasodilation
2) Blood vessels dilate in order to release more macrophages into the interstitial fluid.
What is endotoxin shock?
Endotoxins (lipopolysaccharides) from gram negative bacteria cause a severe drop in blood pressure
How do you treat endotoxin shock?
Treatment involves neutralizing the LPS components and inflammatory-causing cytokines
What is gram-positive sepsis?
Potent exotoxins cause toxic shock syndrome.
Give some examples of gram positive sepsis?
Usually hospital acquired infections such as
- enterococcus faecium and enterococcus faecalis (inhabit the colon, colonize wounds and are resistant to many antibiotics)
Streptococcus and staphylococcus bacteria are …
gram positive bacteria
What are the group B streptococci?
Streptococcus agalactiae which causes neonatal sepsis
What is puerperal sepsis?
Also called puerperal fever and childbirth fever. Caused by streptococcus pyogenes. This is transmitted to the mother during childbirth. Infects the uterus and may progress to infection of the abdominal cavity (peritonitis).
Endocarditis
Inflammation of the endocardium
Subacute bacterial endocarditis
Impairs the function of the heart valves. Alpha-hemolytic streptococci from an oral or tonsil infection.
Acute bacterial endocarditis
Caused by staphylococcus aureus
Pericarditis
Inflammation of the sac around the heart. Caused by streptococci. Fairly rare disease.
Rheumatic fever
Autoimmune complications of streptococcus progenies infections. Inflammation of the heart valves and subcutaneous nodules at the joints owing to immune reaction against streptococcal M protein.
How do you detect these heart diseases?
You will not hear the normal lub-dub but will hear murmurs and other abnormal sounds.
Sydenham’s chorea
Purposeless, involuntary, rapid, uncoordinated, jerking movements. Primarily affecting the face, hands and feet.
Tularemia
Gram-negative bacilli Francisella tularensis. Zoonotic disease transmitted from rabbits, ticks and insects by deer flies. Creates an ulcer at the site of entry. Bacteria reproduce in phagocytes and enlarge regional lymph nodes. Mortality is less than 30%.
Brucellosis (Undulant Fever)
Name for the different animals.
Brucella (aerobic gram-negative rods)
B. abortus - cows
B. suis - swine
B. melitensis - goats, sheep and camels
How is brucellosis transmitted?
Transmitted via milk from infected animals or contact with them. Persists in the reticuloendothelial system (monocytes and macrophages).
What symptoms does Brucellosis cause?
Malaise, night sweats, muscle aches, not usually fatal.
What is anthrax caused by?
Bacillus anthracis: gram-positive, endospore-forming aerobic rod. Found in soil and primarily affects grazing animals. Spores introduced into the body are taken up by macrophages and germinate, enter the bloodstream and release toxins.
How is anthrax treated?
Treated with ciprofloxacin or doxycycline and through vaccination of livestock
What are the virulence factors that bacillus anthraces produces?
1) Protective antigen: binds the toxins to target cells, permitting their entry
2) Edema toxin: causes local swelling and interferes with phagocytosis
3) Lethal toxin: targets and kills macrophages
4) Amino acid capsule that avoids an immune response
Cutaneous anthrax
Endospores enter through a minor cut. 20% mortality without treatment.
GI anthrax
Ingestion of undercooked, contaminated food. 50% mortality rate
Inhalational (pulmonary) anthrax
Inhalation of endospores. Bacteria enter the bloodstream; progresses into septic shock. Near 100% mortality rate!
Ischemia
Loss of blood supply to tissue
Necrosis
Death of tissue
Gangrene
Death of soft tissue
Gas gangrene
Caused by clostridium perfringens (exam!) which is a gram-positive, endospore forming anaerobic rod. Grows in necrotic tissue, produces toxins that move along muscle bundles
How is gas gangrene treated?
Surgical removal of necrotic tissue and/or use of a hyperbaric chamber