Cardiovascular And Nervous System Infections Flashcards
What are the components of blood?
- formed elements
- RBC
- WBC
- Platelets
- plasma
- H20
- solutes (sugas, a.a, ions, proteins)
Where does gas exchange happen?
-Capillaries (02 is being supplied to the cells of the body and where CO2 is entering the blood to be carried back to the lungs
Where are the functions of the capillaries?
- gas exchange
- nutrients/waste exchange
Where are the cells that makes up the walls of capillaries?
-endothelial cells
What is lymph?
- excess liquid that stays outside the capillary bed
- baths most cells in the body
Capillary bed phases
Early: high hydrostatic (blood) pressure pushes H2O, ions, sugars, a.a, very small proteins out = Capillary filtration > creates lymph
Late: low hydrostatic pressure > osmotic pressure pulls some lymph into blood capillaries
What does capillary filtration create?
Lymph
Where is do excess lymph go?
- enters lymphatic capillaries (1 way valves) which converge into lymphatic ducts into lymph nodes
What are the two forces involved in capillary filtration?
- hydrostatic pressure
- affected by dilation of artierioles
-osmotic pressure
What are the “filters” in capillary filtration
- gaps between endothelial cells
- larger gaps= more lymph, large proteins and WBC escape capillaries
What determines how big the arteriole is?
-smooth muscle cells that surround the arteriole - more dilated= higher pressure of blood, more lymph
What are the functions of a lymph node?
- immune system surveillance
- looks for signs of infection in lymph
Which WBCs are in the lymph node?
- B+T lymphocytes
- B Cells: B activation; they reproduce and become plasma cells which secrete antibodies
- T cells: kill human cells with intracellular pathogens (CD8) or regulate the immune system (CD4)
- Macrophages
- Dendritic cells cells
What is the disease called when you have inflammation in a lymphatic capillary or vesicle ?
-lymphangitis
What is the disease called when there is swelling of a lymph node?
-lymphadenopathy
What are 2 examples of non blanching rashes?
- Petechia (smaller)
- Purpura (larger)
- pathogen is attacking a capillary or the immune system is triggered to attack the capillaries.
- Endothelial cells are being damaged=blood gets leaked out=gets trapped in dermal layers on skin
What is a plague?
- refers to the disease caused by yersinia pestis
- Gram - bacteria
- reservoir = rodents
- transmitted to humans via flea bites
What are the 3 types of plague
- bubonic plague
- septicemic
- pneumonic
Characteristics of septicemic plague
- bacteria from lymph nodes > bloodstream
- non transmissible
- death of tissues at the end of extremities (toes, fingers)
- case mortality rate: (treated/untreated): 40%/100%
Characteristics of pneumonic plague
- bacteria from lymph nodes > lungs
- easily transmissible (coughing)
- Case Mortality rate: (untreated/treated):100% (24hr survival rate)
Cycle of Plague
-
Characteristics of bubonic plague
- bacteria from flea bite site to lymph nodes, which swell (buboes)
- not transmissible
- Case mortality (treated/untreated): 5-10%/ 50%
What are the virulence factors of Y. Pestis (plague)
- atypical lipid A in LPS
- does not activate the immune system
- lipoproteins/protein capsule
- prevents WBC phagocytosis
- adhesins
- attach to human cells
- needle like secretion system
- injects toxins into WBC
- biofilm
- causes flea to feel starved
What are the effects of the toxins Y. Pestis (plague) injects into WBCs?
-interferes with cytoskeleton of WBC
- interferes with H+ ion pump
- does not activate acid hydrolases
-toxin that trigger apoptosis of WBC
What are the layers that surround the brain? (3)
- meninges
- Dura mater
- arachnoid mater
- pia mater
What type of fluid is found in the subarachnoid space?
Where is it made?
- cerebrospinal fluid (CFS)
- choroid plexus
What is the function of CFS?
- supplies a cushion to the brain
- helps deliver nutrients to brain cells
Characteristics of brain capillaries compared to normal capillaries
Normal Capillaries
-endothelial cells have small gaps between them
Brain Capillaries
- endothelial cells have more tight junctions - wrapped with projections (feet) from astrocytes (glial cell)
What is the blood brain barrier (BBB)?
- protects brain from pathogens and poisons
- slows delivery of medications
What is meningitis?
The inflammation of the meningis
Define encephalitis
-inflammation of brain tissue
Define meningoencephalitis
-when both the meninges and brain tissue are inflammed
Define immunopathlogy
-damage caused to human tissues due to the immune response
Symptoms of bacterial meningitis
- initial: fever, headache, stiff neck, irritability
- nausea vomiting
- decreased cognition
- convulsions and coma
- death from shock and inflammation
- endotoxin
What are the 3 species of bacterial meningitis talked about in lecture?
- haemophilus influenzae
- Nesseria meningitidis
- streptococcus pneumonia
-Characteristics of Haemophilus influenzae
- gram negative
- capsule
- microflora of throat
- causes 50% of most bacterial meningitis
- low case mortality: 6%
What does Hib stand for?
- serotype B (capsule) Haemophilus influenzae
- the capsule is the target of the Hib vaccine
Characteristics of Neisseria meningitidis
- gram negative cocci
- capsule
- 4/10 people have this attached to epithelial cells in the back our our nose, throat, nasopharynx
- with treatment=10 % mortality rate
- without: 80%
Define meningococcal meningitus
- caused by Neisseria meningitidis
Characteristics of streptococcus pneumonia
- gram positive
- diplococci
- capsule
- 7/10 people have them in the throat
-
What can you grow in chocolate agar?
- haemophilus influenzae
- Neisseria meningitidis
- streptococcus pneumoniae
What causes tetanus
-gram positive bacteria clostridium tanae
- spores get into wound»_space; tissue damage/necrosis creates anaerobic conditions
- spores germinate and release tetanus toxin
- toxin enters neurons, transported to spinal cord
Symptoms of Tetanus
- motor neurons become overstimulated
- muscle spasms
- difficulty swallowing
- titanic paralysis (all muscles contracting)
- respiratory failure
How is tetanus prevented?
-toxoid vaccine: stimulates the production of antibodies against tetanus toxin
How does the tetanus toxin affect the CNS
-stops the release of inhibitory neurotransmitters (GABA) by presynaptic neurons in spinal cord
What is chocolate agar?
Lysed RBCs
