week 3 Flashcards
what body temperature is considered a fever?
100.4 F, 38.5 C
____ days and under, a child must undergo a full sepsis workup (labs, XR, cultures, LP) for every fever
28
phases of wound healing:
inflammatory (includes extravasation)
proliferative (granulation)
remodeling (maturation)
what are the stages of the inflammatory phase of wound healing?
hemostasis
- platelet aggregation
- vasoconstriction for a short time
clotting
- fibrinogen turned to fibrin (via thrombin)
- clotting factors (collagen and basement membrane proteins)
vasodilation
- histamine and nitric oxide release
- extravasation - migration of leukocytes, edema, toxic debris dilution etc.
what are the phases of extravasation? list the proteins/receptors associated with each.
rolling
- selectin on endothelium
- sialyl Lewis X on leukocyte
- allows the leukocyte to “roll” across the endothelium
adhesion
- ICAM, VCAM on endothelium
- integrin on leukocyte (activated by cytokines from macrophage)
- binds/adheres strongly to the endothelium
transmigration/diapedesis
- PECAM on both endo and leuk
- leukocyte passes through the endothelium
migration
-leukocyte migrates and binds to the ECM of the wound site (using integrin)
what occurs during the proliferative phase?
fibroblasts migrate in -collagen III -collagen I granulation (primary tissue to form) angiogenesis epithelialization wound contraction
describe the remodeling phase?
reorganization of the collagen composition
collagen crosslinking
tissue becomes more normal/stable
types of scars:
keloid: overgrowth of collagen, past the wound’s boundaries
hypertrophic: raised, red, and itchy; does not extend past boundary
atrophic: indented, e.g. acne scars
stretch marks
list the 3 types of intention:
primary - clean cut surgical incision, no infection
secondary- due to injury or trauma, ragged edges, can be infected, results in scaring
tertiary or delayed primary - left open due to possibility of infection, grafts, a lot of scarring
effects of competitive inhibition:
Km increase
-need more substrate in order to outcompete the inhibitor and to bind half the enzyme’s active sites
Vmax same
-if it outcompetes, it has the potential to have the same end result
describe the role of malate in inhibtion:
malate is a competitive inhibitor in fumarate synthesis
binds to the enzyme complex that typically binds succinate (substrate analogue, same 3D shape)
succinate + enzyme —-> fumarate and enzyme
describe the relationship between Km and enzyme affinity
increasing Km, lowering affinity (need more substrate for same job)
decreasing Km, increasing affinity (can do the same job for a lot less)
what drugs inhibit folic acid synthesis from PABA + pteridine and glutamic acid?
sulfa drugs
issues with methanol metabolism:
forms formic acid which causes metabolic acidosis, neurotoxicity, and causes direct damage to the optic nerve (visual impairments or blindness)
treatment for methanol poisoning: treat patient with ethanol/fomepizole (alcohol DH competitive inhibitor, blocks the formation of formaldehyde and therefore formic acid)
issues with ethylene glycol metabolism:
produces oxalic acid (toxic)
forms with calcium to form calcium oxalate in the kidneys: renal necrosis (nephrotoxic)
treatment: treat patients with ethanol/fomepizole (alcohol dehydrogenase) competitive inhibitor, prevents the formation of glycol aldehyde
target enzyme and therapuetic use: STATINS
HMG-CoA reductase
decrease plasma cholesterol, anti-hyperlipidemic drug
target enzyme and therapeutic use: allopurinol
xanthide oxidase, gout
target enzyme, therapeutic use: methotrexate
dihydrofolate reductase, cancer
target enzyme, therapeutic use: captopril, enalpril
angiotensin converting enzyme: HTN
target enzyme, therapeutic use: dicoumarol
vitamin K epoxide reductase, anticoagulant
effects of noncompetitive inhibitor:
Km no change
Vmax decreased
effects of Uncompetitive inhibition?
Kmax decrease
Vmax decrease
alanine and ATP are _____ inhibitors of _______.
noncompetitive, pyruvate kinase
explanation: pyruvate breaks down into alanine and an ATP molecule is generated when pyruvate is produced, when these products build up it signals to the glycolic pathway that it should slow down. prevents energy wasting.
cyanide is a __________ inhibitor of ____________.
irreversible, cytochrome C oxidase (ETC)
___________(drug) inhibits the activity of __________(enzyme) in treatment for AIDS.
NNRITs, reverse transcriptase
NNRIT (no nucleoside reverse transcriptase inhibitor) blocks the conversion of HIV RNA into HIV DNA (via blocking reverse transcriptase)
effects of prostacyclin (PGI2):
- produced mostly in epithelium
- INHIBITS platelet aggregation (increases cAMP)
- vasodilation
**opposing effect of thromboxane A2
**injury to the vessel wall inhibits its synthesis so that platelet aggregation can occur
effects of thromboxane A2:
- produced mainly in the platelets
- PROMOTES platelet aggregation (decreases cAMP)
- vasoconstriction
- mobilize cellular calcium
- contraction of smooth muscle
**opposing effect of prostacyclin (PGI2)
effects of prostaglandin E2:
- VASODILATION
- relaxes smooth muscles
- modulation of inflammation
- causes FEVER and PAIN
- used to induce labor
**role in inflammation by increasing capillary permeability, erythema and wheel formation
effects of prostaglandin F2alpha:
- VASOCONSTRICTION
- contracts smooth muscles
- stimulates uterine contractions
- role in LH induced ovulation
what drug inhibits phospholipase A2?
corticosteroids (e.g. annexin A1)
**phospholipase A2 releases AA from the phospholipid membrane in response to a stimulus
what drug inhibits COX 1 and COX2?
COX1: low dose Aspirin, NSAIDS
COX2: Aspirin (higher dose?), NSAIDs, Coxibs
how does aspirin inhibit COX1?
- acetylates the serine OH reside in the enzymes channel
- IRREVERSIBLE inhibition
- this bulky addition prevents AA from accessing the channel
- thromboxane production is prevented
- therefore, platelet aggregation decreases (anti-thrombotic property of ASA)
what is the optimum temperature for enzyme activity/metabolism in humans?
37 deg C
posterior hypothalamus responds to cold sensed by skin thermoreceptors by:
skeletal muscles
- increases shivering
- ATP to ADP (exothermic)
sympathetic NS - catecholamines (epi, nepi)
- alpha 1 receptors in blood vessels/ vascular smooth muscle: vasoconstriction (reduced heat loss)
- B receptors in brown adipose tissue: burns calories to generate heat
anterior hypothalamus responds to increasing temperatures by:
stimulating sympathetic cholinergic receptors: stimulate sweat glands to increase sweating (evaporative cooling)
decreases sympathetic activity in vasculature/blood vessels - vasodilation, increase blood flow to skin, increase heat loss
what are the phases of heat stress?
- heat cramps
- heat syncope - lack of adequate blood to the brain
- heat exhaustion - acute plasma loss
- heat stroke - hypothalamus failing, dry hot skin
what is the process for heat adaptation to warm climates?
2 week process
increase sweating rate, sweat earlier
decreased salt excretion in urine
more salt reabsorbed via aldosterone – increased water retention
what is the feedforward process between the skin thermoreceptors and hypothalamus?
the skin senses a change in the environmental temperature and signals to the hypothalamus before the core body temperature drops or raises