G7_Probe_Human Physiology in Extreme Heat and Cold

Question 1

internal organ temperature is referred as

Answer 1

body core temperature (Tc)

Question 2

the clinical standard method for determining core temperature

Answer 2

rectal thermometry

Question 3

defined as the temperature of the surrounding environment, unaltered by direct human intervention

Answer 3

ambient temperature

Question 4

There are three main ways by which human temperature is affected

Answer 4

climate temperature
autonomic nervous system
human behavioural temperature regulation

Question 5

a fundamental capacity of the autonomic nervous system to respond to cold and heat stress conditions

Answer 5

Thermoregulation

Question 6

The two most paradigmatic life-menacing states are:

Answer 6

hyperthermia and hypothermia.

Question 7

“a rise in body temperature above the hypothalamic set point when heat-dissipating mechanisms are impaired (by drugs or disease) or overwhelmed by external (environmental or induced) or internal (metabolic) heat”

Answer 7

Hyperthermia

Question 8

an elevated core temperature of 40.5 °C or more because of a failure of thermoregulation due to an increase in heat production that overwhelms the heat dissipating mechanisms

Answer 8

Hyperthermia

Question 9

a disorder where body core temperature decreases below 35 °C

Answer 9

Hypothermia

Question 10

In the cardiovascular system, at the beginning of hypothermia, the sympathetic tone increases due to the ___ in body core temperature secondary to the cold stressful environment

Answer 10

decrease

Question 11

is another vasomotor response intimately related, which modulates the effect of peripheral vasoconstriction periodically, increasing blood flow and, as it is believed, preventing cold injuries while improving dexterity and tactile sensitivity

Answer 11

Cold-induced vasodilation (CIVD)

Question 12

is the initial response to cold but it is followed with hypoventilation as the extreme cold exposure is maintained

Answer 12

Hyperventilation

Question 13

produces an increase in carbon dioxide in blood

Answer 13

Hypoventilation

Question 14

In the gastrointestinal system, intestinal motility ___ progressively as temperature does too

Answer 14

decreases

Question 15

Hypothermia induces secretion of ___ and inhibits duodenal bicarbonate secretion leading to mucosal damage in the stomach and duodenum

Answer 15

gastric acid

Question 16

The effects of extreme cold in the hematologic system consist in an increase of patient’s ___ and ___ due to hemoconcentration

Answer 16

haemoglobin
haematocrit

Question 17

The human spleen sequesters ___ densely packed red blood cells

Answer 17

200-250 mL

Question 18

Spleen contraction seems to be mediated by ___

Answer 18

α-adrenoreceptors

Question 19

Shivering mechanism ceases at approximately ___ °C

Answer 19

31

Question 20

an important actor against cold stress in human infants through non-shivering thermogenesis
(NST)

Answer 20

Brown adipose tissue (BAT)

Question 21

BAT heat production depends on a mitochondrial process called ___

Answer 21

uncoupled respiration

Question 22

uncoupled respiration is mediated by the ___

Answer 22

uncoupling protein-1 (UCP1)

Question 23

The respiratory system adaptations to heat are primarily ___ and ___

Answer 23

hyperpnea and hypocapnia

Question 24

Splanchnic blood flow is reduced through ___ to compensate the decreased central blood volume, consequence of the reduced plasma volume and blood pooled to the skin for heat dissipation

Answer 24

vasoconstriction

Question 25

produces cell injury

Answer 25

Heat

Question 26

Heat releases ___ into systemic circulation mediating fever, leucocytosis, muscle catabolism and activation of endothelial cells

Answer 26

cytokines

Question 27

In the state of hyperthermia, the renal system manifests itself clinically with ___ and ___

Answer 27

oliguria renal failure

Question 28

The water loss increases the salt concentration in blood which is sensed by the macula densa cells in the juxtaglomerular apparatus releasing renin and activating the ___ to increase the reabsorption of salt and indirectly, water

Answer 28

renin-angiotensin-aldosterone system (RAAS)

Question 29

The osmostat, located in the hypothalamus, senses the osmolality of the extracellular fluid which is going to be high, and will release ___

Answer 29

antidiuretic hormone (ADH)

Question 30

(ADH) is stored in the ___

Answer 30

posterior pituitary gland

Question 31

In the integumentary system, hyperthermia clinical symptoms are ___ and __

Answer 31

sweating flushing

Question 32

the main organ related to heat dissipation

Answer 32

skin

Question 33

When the body is exposed to extreme heat conditions, the body most important mechanism to dissipate heat and prevent an increase in core temperature is

Answer 33

sweating

Question 34

In cold conditions, in order to prevent hypothermia, the body’s main objective is heat conservation predominantly through ____ to shift blood from the periphery to the internal and vital organs

Answer 34

peripheral vasoconstriction