BSNC 3000 Final questions with verified answers
Does blood perfuse the coronary circulation during systole or diastole?
Ans✔✔-Diastole
What happens to myocardial blood flow when heart rate increases?
Ans✔✔-When heart rate increases, the cardiac cycle is shortened in
duration; less time is spent in diastole, which decreases the time
available for coronary perfusion.
70% of oxygen in coronary blood is extracted by the myocardium at rest.
This means that there is little oxygen reserve when myocardial demand
increases. What must happen when oxygen demands of the heart
increase to ensure adequate oxygen supply? Ans✔✔-If oxygen demands
of the heart increase, coronary blood flow must increase (e.g. v/d d/t
NO)
which portion of the heart is first affected by MI? Ans✔✔-the first inner
third (furthest away from the coronary artery and subject to higher
pressures from the inside of the heart)
subendocardial infarct Ans✔✔-sudden reperfusion of coronary artery
following an MI, where only the inner third of the ventricle wall is
irreversibly damaged (infarct)
N-STEMI
can also be caused by conditions that dec perfusion:
,- severe atherosclerosis
- hypotension
sources of heat gain Ans✔✔-external sources
- cell metabolism
- muscle activity
- ingestion of food
sources of heat loss Ans✔✔-- evaporation of sweat
- through the skin
- breathing
What regulates body temperature? Ans✔✔-hypothalamus - determines
set point
why are older adults at risk for hypothermia? Ans✔✔-less heat gain:
- smaller meals
- mobilize less (less muscle activity)
- less cellular metabolism
more heat loss:
- less fat -> more heat loss
,why does stress inc body temp? Ans✔✔-PSR -> inc metabolism
inc muscle tension
vasoconstricton -> less heat loss
fever definition Ans✔✔-increase in core body temperature d/t resetting
of thermodynamic set point in response to pyrogens
is PSR the cause of fever? Ans✔✔-alone, no.
if underlying cause of PSR causes the release of pyrogens (infection),
then yes
general causes of fever (2) Ans✔✔-infection
inflammation
causes of hyperthermia Ans✔✔-malignant hyperthermia
PSR
malignant hyperthermia Ans✔✔-A hereditary condition of uncontrolled
heat production that occurs when susceptible people receive certain
anesthetic drugs.
causes of hypothermia Ans✔✔-heat loss during sx (open body cavity,
anesthesia, cold OR)
, therapeutic hypothermia (dec metabolic demand)
exogenous pyrogens Ans✔✔-e.g. from bacteria cells walls; act indirectly
by stimulating the release of endogenous pyrogens (cytokines)
endogenous pyrogens Ans✔✔-cytokines released by macrophages and
leukocytes
IL-1, TNF-alpha
physiology of fever Ans✔✔-1. endogenous pyrogens enter circulation ->
brain
2. synthesis of PGE2 by endothelial cells close to the hypothalamus
3. PGE2 acts on hypothalamus -> resets thermoregulatory set point
(higher)
stages of fever Ans✔✔-- chill phase (baselines temp below new set
point)
- fever
- defervescence phase (pyrogens cease to act; mechanisms to dec temp
to normal)
Does blood perfuse the coronary circulation during systole or diastole?
Ans✔✔-Diastole
What happens to myocardial blood flow when heart rate increases?
Ans✔✔-When heart rate increases, the cardiac cycle is shortened in
duration; less time is spent in diastole, which decreases the time
available for coronary perfusion.
70% of oxygen in coronary blood is extracted by the myocardium at rest.
This means that there is little oxygen reserve when myocardial demand
increases. What must happen when oxygen demands of the heart
increase to ensure adequate oxygen supply? Ans✔✔-If oxygen demands
of the heart increase, coronary blood flow must increase (e.g. v/d d/t
NO)
which portion of the heart is first affected by MI? Ans✔✔-the first inner
third (furthest away from the coronary artery and subject to higher
pressures from the inside of the heart)
subendocardial infarct Ans✔✔-sudden reperfusion of coronary artery
following an MI, where only the inner third of the ventricle wall is
irreversibly damaged (infarct)
N-STEMI
can also be caused by conditions that dec perfusion:
,- severe atherosclerosis
- hypotension
sources of heat gain Ans✔✔-external sources
- cell metabolism
- muscle activity
- ingestion of food
sources of heat loss Ans✔✔-- evaporation of sweat
- through the skin
- breathing
What regulates body temperature? Ans✔✔-hypothalamus - determines
set point
why are older adults at risk for hypothermia? Ans✔✔-less heat gain:
- smaller meals
- mobilize less (less muscle activity)
- less cellular metabolism
more heat loss:
- less fat -> more heat loss
,why does stress inc body temp? Ans✔✔-PSR -> inc metabolism
inc muscle tension
vasoconstricton -> less heat loss
fever definition Ans✔✔-increase in core body temperature d/t resetting
of thermodynamic set point in response to pyrogens
is PSR the cause of fever? Ans✔✔-alone, no.
if underlying cause of PSR causes the release of pyrogens (infection),
then yes
general causes of fever (2) Ans✔✔-infection
inflammation
causes of hyperthermia Ans✔✔-malignant hyperthermia
PSR
malignant hyperthermia Ans✔✔-A hereditary condition of uncontrolled
heat production that occurs when susceptible people receive certain
anesthetic drugs.
causes of hypothermia Ans✔✔-heat loss during sx (open body cavity,
anesthesia, cold OR)
, therapeutic hypothermia (dec metabolic demand)
exogenous pyrogens Ans✔✔-e.g. from bacteria cells walls; act indirectly
by stimulating the release of endogenous pyrogens (cytokines)
endogenous pyrogens Ans✔✔-cytokines released by macrophages and
leukocytes
IL-1, TNF-alpha
physiology of fever Ans✔✔-1. endogenous pyrogens enter circulation ->
brain
2. synthesis of PGE2 by endothelial cells close to the hypothalamus
3. PGE2 acts on hypothalamus -> resets thermoregulatory set point
(higher)
stages of fever Ans✔✔-- chill phase (baselines temp below new set
point)
- fever
- defervescence phase (pyrogens cease to act; mechanisms to dec temp
to normal)
