on Claire Neufeld's set) Questions and
Correct Answers
Describe homeostasis vs. allostasis ✅Hemostasis: Stability of systems which maintain
life
Allostasis: Adaption of certain systems to changing external and internal environment
formula for cardiac output ✅heart rate x stroke volume
Describe Cardiac preload ✅Volume of blood returned to the heart pre-systole - exerts
pressure on the ventricle walls
- Described as the filling force applied to the heart.
- When the heart stretches it generates more force to effectively pump the increased
load - Frank-Starling mechanism. (has limits)
- Increased preload increased the oxygen demand of the myocardium, but is more
oxygen-efficient than increasing the heart rate.
Describe cardiac afterload ✅Described as the pressure the ventricle must overcome to
eject blood into the arteries.
- During contraction, the left ventricle must generate more pressure than aortic diastolic
pressure.
- Also, the pressure must be great enough to overcome the peripheral resistance.
- Reducing the afterload with vasodilators is a useful therapy for a failing heart.
- Increased afterload can decrease stroke volume
MAP calculation formula ✅MAP = (SBP+DBP+DBP)/3
Gravity reduces MAP above heart level, increases below
What does SVR mean? ✅systemic vascular resistance
- SVR is determined by the arteriole diameter, where vasoconstriction increases SVR
and vasodilation decreases it. An increase in blood viscosity (thickness) also increases
SVR.
List the five vital signs ✅- Temperature
- Pulse
- Blood Pressure
- Respiration
- Oxygen saturation (pulse oximetry)
List the normal ranges of all five vital signs ✅o Temperature Range: 36°C to 38°C* -
Average oral/tympanic/temporal: 37°C, Average rectal: 37.5°C, Average axillary: 36.5°C
, o Pulse 60-100 beats per minute
o Respirations 12-20 breaths per minute
o Blood Pressure Systolic: 120-139 mm Hg, Diastolic: 80-89 mm Hg, Pulse pressure:
30-50 mm Hg
List the six sites of measurement for core temperature
List the three sites of measurement for surface temperature ✅o Core Temperature:
Rectum, Tympanic membrane, Temporal artery, Esophagus, Pulmonary artery, Urinary
bladder
o Surface Temperature: Skin, Mouth, Axillae
Which brain structure controls temperature? ✅hypothalamus
List 6 common influences on true temperature ✅- Infection and Inflammation
- Diurnal cycle (similar to circadian), Menstrual cycle, Exercise, Age (child, elder)
Describe mechanisms for heat loss ✅sweating, vasodilation (widening) of blood
vessels, and inhibition of heat production. Blood is redistributed to surface vessels to
promote heat loss.
Describe heat conservation mechanisms ✅vasoconstriction (narrowing) of blood
vessels reduces blood flow to the skin and extremities. Compensatory heat is produced
through voluntary muscle contraction and muscle shivering.
Assessment of the average BMR depends on what factor?
- List two factors which significantly affect BMR ✅Depends on body surface area
o By promoting the breakdown of body glucose and fat, thyroid hormones increase the
rate of chemical reactions in almost all cells of the body. Absence of thyroid hormones
can reduce the BMR by half, causing a decrease in heat production.
o The male sex hormone testosterone increases BMR. Men have a higher BMR than do
women.
Describe non-shivering thermogenesis
- Which age group is most likely to exhibit? ✅occurs primarily in newborns and is the
main source of heat generation due to their inability to shiver.
- Sympathetic nerve endings secrete norepinephrine in response to chilling, which
stimulates fat metabolism in the richly vascularized brown adipose tissue to produce
internal heat that is conducted to surface tissues through the blood
Describe the 5 types of heat loss ✅o Radiation is the transfer of heat from the surface
of one object to the surface of another without direct contact between the two.
o Conduction is the transfer of heat from one object to another through direct contact.
o Convection is the transfer of heat away from the body by air movement.
o Evaporation is the transfer of heat energy when a liquid is changed to a gas.