Thermoregulation, BMR, Basic Nutrition Flashcards
(95 cards)
1
Q
Average core temp is between:
A
98F (36.7C) and 98.6F(37C) orally can range from 97-99.5
2
Q
Skin temperature:
A
rises and falls with temperature of surroundings and structures lying beneath it
3
Q
We consider someone febrile at:
A
100.4 F or 38C
104 F or 40C is getting dangerous
4
Q
Sites used for core measurement:
A
rectal, oral, vaginal, bladder, tympanic
5
Q
how we measure surface measurement:
A
axillary, skin of forehead, non-contact IR devices
6
Q
Thermoregulation basics: body temp is controlled by:
A
balancing heat production against heat loss
heat production>heat loss=rise in body temp
heat loss>heat production=decrease in body temp
7
Q
Homeostatic receptors are:
A
sensors that monitor environment and respond to changes
8
Q
control center in homeostasis determines:
A
set point which is the range at which variable is maintained
9
Q
the effector in homeostasis:
A
means for the control center’s response(output) to the stimulus
10
Q
Heat production is a by-product of:
A
metabolism
11
Q
extra rate of metabolism caused by:
A
muscle activity (shivering)
thyroxine
effects of epinephrine, norepinephrine, and sympathetic stimulation of cells
increased chemical activity in the cells themselves
metabolism needed for digestion, absorption, and storage of foods
12
Q
Most heat is produced in deep organs at ____, and skeletal muscles during_____
A
rest, exercise
13
Q
heat is transferred to the skin where it is lost to the air and other surroundings; the rate at which heat is lost depends primarily on:
A
- how rapidly heat can be conducted from where it is primarily produced to the skin
- how rapidly heat can be transferred from the skin to the surroundings
14
Q
Insulation:
A
skin and especially the subcutaneous tissues act together as a heat insulator
fat conducts heat only 1/3 as readily as other tissues
in the cold, minimal amounts of blood flow from the heated internal organs to the skin=effective means of maintaining normal internal core temp
15
Q
heat transfer to skin..
A
blood vessels distributed profusely throughout the skin
rate of blood flow into skin venous plexus can vary from barely above 0 to as great as 30% of cardiac output
16
Q
Low rate of skin flow occurs in ____ temps, and _____ heat conduction and _____heat is lost
A
colder, decreases, less
17
Q
high rate of skin flow occurs in _____, ________ heat conduction, and _____ heat is lost
A
warmer, increases, more
18
Q
four types of heat loss from skin surface
A
radiation
conduction
convection
evaporation
19
Q
- Radiation is:
2. When temp of body>temp of surroundings:
A
- the loss of heat in form of infrared heat rays (all objects not at absolute zero temp radiate such rays, including the walls and objects around us)
- a naked person will lose about 60% of total heat by radiation at normal room temp - a greater quantity of heat is radiated from the body than is radiated to the body
20
Q
- Conduction is:
2. once the temp of the air adjacent to the skin=temp of skin…
A
- the direct loss of heat via kinetics or the energy of molecular motion..transfer of heat through physical contact
- no further loss of heat occurs via conduction to air
conduction to objects only accounts for 3% where as conduction to air about 15% in conduction with convection
21
Q
Convection:
A
aka the wind chill process; the removal of heat from the body by air currents
wind removes layer of air immediately adjacent to the skin and replaces it by new air much more rapidly
22
Q
What would happen with the air convection process when one wears clothes?
A
normal clothing decreases heat loss by 1/2
arctic-type clothing decreases heat loss to as little as 1/6th
23
Q
with regard to conduction and convection with water, each unit of water adjacent to the skin can absorb far greater quantities of heat than air can therefore…
A
the rate of heat loss to water is usually many times greater than the rate of heat loss to air
24
Q
- Evaporation is:
- Evaporation _______ be controlled for purposes of temp regulation
- Loss of heat via evaporation of sweat can be controlled by __________
A
- the loss of heat when water evaporates from body surface
can occur even when person is not sweating=insensible loss when unable to detect sweat-occurs at a rate of about 600-700 mL/day - cannot
- regulating rate of sweating
25
Heat loss with sweating is controlled by what nervous system?
sympathetic
26
two types of sweat glands
Eccrine: innervated by somatic nervous system via Ach
Apocrine: regulated by androgens
27
1. If skin temp>temp of surroundings, heat can be lost by _________
2. once temp of surroundings > skin temp, the body then gains heat by both _______
3. under these conditions, the only means by which the body can rid itself of heat is by ______
1. radiation and conduction, sometimes convection
2. radiation and conduction
3. evaporation
28
Organ systems responsible for heat loss and how:
skin: vasodilation and perspiration
cardiovascular: increased cardiac output to compensate for peripheral vasodilation with increased volumes of blood to periphery
respiratory: some degree of evaporation
29
Temperature is regulated by:
the hypothalamus
30
Thermostatic detection occurs in the hypothalmic area of the brain as well as in the:
skin and deep body tissues
31
Heat sensitive cells function
signals sent to skin to induce sweating
vasodilation of skin vessels
decrease in heat production (inhibition of shivering and chemical thermogenesis)
32
cold sensitive cells:
| what is piloerection?
Piloerection-brings hairs in upright position as in goose bumps
vasoconstriction of skin vessels
increase in heat production (shivering, thyroxine secretion)
33
Hyperthermia is a:
state of unusually high core body temp
34
Predisposing factors of hyperthermia include age and health of the pt. Patients with type 1 DM can become hyperthermic more easily because _______
of the damage to their autonomic nervous system
35
Medications that can be a predisposing factors for hyperthermia are:
diuretics-dehydration
beta blockers-can cause vasodilation through blockade of alpha-adrenergic receptors
psychotropics-can affect CNS regulation
36
other factors that predispose pt to hyperthermia:
level of acclimation: adjust to environment change
length and intensity of exposure
environmental factors like humidity and wind
37
Heat cramps:
usually caused by:
treated with:
painful, easily treated, acclimation occurs like muscle soreness
-painful contractions of larger muscle groups during or shortly after strenuous exercise in the heat
-caused by replacement of water without adequate salt resulting in a low sodium state in the muscles
-treated with cooling measures, fluids, electrolyte replacement, oral or IV
no changes in mental status or fever
38
Heat exhaustion:
caused by:
Symptoms:
Treated with:
serious but no organ damage, mild hyperprexia ( elevation of core temperature)
Caused by salt or water depletion in the face of heat stress
Symptoms include mild hyperprexia, nausea, vomiting, lightheadedness, dehydration with minimal altered mental status; leads rapidly to heat stroke if not rapidly reversed
Treated with cooling measures and IV normal saline-further electrolyte replacement guided by serum electrolyte levels
39
Heat stroke characteristics:
results from:
symptoms that can arise:
-critical organ damage, sign. mortality, elevated body temp, usually >105f, 40.5C
-results when the body's thermoregulatory mechanisms are overwhelmed by the heat stress; body temp rises markedly with eventual multisystem organ failure-like kidneys shutting down
-in severe cases, pt may become confused and/or agitated
tachycardia and tachypnea with hypotension-shock symptoms
40
Exertional Heatstroke
occurs in younger, physically fit with normal thermoregulatory systems
frequently not dehydrated and may be wet with perspiration
sign. elevated body temp due to stress
41
Classic Heatstroke
occurs in older or debilitated exposed passively to sign. thermal stress over hours or days
- ability to respond can be compromised by CV disease, drugs, alcohol
- usually perspiring for sign. time and profoundly dehydrated
42
Treatment of heatstroke:
```
ABCs
cooling measures to lower the pts temp to < 101F/38.3 within an hour
prevent shivering
keep pt NPO
IV NS
fluid boluses
oxygen
cardiac monitoring
anticipate seizures! treat with valium
```
43
Hypothermia defined as:
core temp. of less than 35c/95f
mild, moderate, severe
-mostly seen in cold climates but can develop without exposure to extreme environmental conditions
44
age groups at risk for hypothermia
elderly lose their ability to sense cold
neonates have large surface-to-volume ratio
both groups have limited ability to increase heat production and conserve body heat
individuals with an altered sensorium like alcohol, drugs, trauma
45
pathophysiology of hypothermia:
heat generated by:
heat preserved by:
heat is generated by cellular metabolism (heart and liver)
loss occurs through the skin and lungs via: evaporation, radiation, conduction, convection
heat preserved by: peripheral vasoconstriction, shivering, nonshivering thermogenesis=increase in metabolic rate from thyroid and adrenal glands
46
Mild hypothermia presentation:
tachypnea, tachycardia, hyperventilation
ataxia, dysarthria(trouble speaking), impaired judgement
shivering
cold diuresis=increased urinination due to increased blood pressure (look at slide)
47
Presentation of moderate hypothermia
sinus bradycardia, decreased cardiac output, hypoventilation, afib, junctional bradycardia, other arrhythmias
CNS depression, hyporeflexia
decreased renal blood flow and loss of shivering
paradoxical undressing
48
presentation of severe hypothermia
pulmonary edema, oliguria(no urine produced), areflexia, coma, hypotension, bradycardia, ventricular dysrhythmias, asystole
49
diagnosis of hypothermia
must use low reading electronic thermometer
labs to identify potential complications:
electrolytes, hematocrit, coagulation studies, ABGs, EKG: elevation of the J point or J or Osborne wave
50
Management of hypothermia
```
ABCs
initiation of rewarming:
passive external rewarming
active external rewarming: combination of warm blankets, radiant heat, warm baths or forced warm air
active internal rewarming
```
51
why do you have to be careful in rewarming pt in hypothermic conditions?
risk is core temperature after-drop which occurs when trunk and extremities warmed simultaneously
warm trunk 1st and minimize use of peripheral muscles!
52
active internal rewarming
can be used alone or with active external rewarming
pleural and peritoneal irrigation with warm saline
hemodialysis and cardiopulmonary bypass
warm humidified oxygen
warm IV fluids and bladder or GI irrigation with warm saline may be used
53
treatment of hypothermia induced dysrhythmias
hypothermic heart is very sensitive to movement so rough handling of the pt can precipitate dysrhythmias
afib and flutter usually resolve with rewarming
can not manage vfib or asystole until core temp is brought up to 86-90f/30-32.2c
54
metabolic rate and what it is estimated by:
metabolic rate is the energy expenditure per unit time (calories per hour)
estimated by food consumption, energy released as heat, oxygen used in metabolic processes
55
factors that influence metabolic rate:
exercise
food intake
shivering
anxiety
56
Basal metabolic rate defined as:
-the minimal rate of energy expenditure per unit time by endothermic animals at rest
-also the energy output of the body to perform essential metabolic functions
body's idling speed-the minimal waking rate of internal energy expenditure
57
BMR assessed by:
direct calorimetry-measured rate of heat production
| indirect calorimetry-measured oxygen consumption
58
factors that influence BMR:
food intake
thyroid hormone
activity level
age
59
energy definition:
| calorie:
the capacity to do work
-calorie is the amount of heat energy necessary to raise the temperature of 1 gram of water 1 degree centigrade
nutritional calorie is 1000 calories or the kilocalorie
60
Neutral energy balance occurs:
positive energy balance occurs:
negative energy balance occurs:
1. when input and out match
2. when intake exceeds output..energy is stored as glycogen or fat
3. when output exceeds intake..energy stores are depleted
61
food intake is controlled by the:
hypothalamus (partially)
feeding centers: lateral hypothalamus
satiety centers: ventromedial hypothalamus
62
factors that affect food intake:
pre gastric factors: appearance of food, taste/odor of food, learned preferences and aversions, psych factors
gi and postabsorptive factors
long-term controls-results from complex integration of hormonal, neural, metabolic signals
63
Protein degradation:
the splitting of proteins by hydrolysis of the peptide bonds with formation of smaller polypeptides
64
fat synthesis:
creation of fatty acids from acetyl co A and malinyl-coA precursors through action of enzymes called fatty synthesis
65
fat breakdown:
process in which fatty acids are broken down into their metabolites, in the end generating acetyl-coA
66
Anabolism
```
requires energy(ATP)
an anabolic reaction is one than involves creating large molecules out of smaller molecules -when body makes fat out of extra nutrients you eat
```
67
catabolism:
produces energy
| a catabolic reaction is one that breaks down large molecules to produce energy like in digestion
68
the pancreas produces 2 _______ hormones to control blood sugar:
antagonistic
| insulin and glucagon
69
insulin is produced by what cells and what is it action on blood sugar:
```
beta cells in islets of langerhans
facilitates glucose entry in cells
stimulates glycogenesis
inhibits glycogenlysis
inhibits gluconeogenesis
```
70
insulins action on fat:
increases transport into adipose cells
promotes protein synthesis
inhibits protein degradation
71
insulin action on protein:
promotes uptake of amino acids by muscle and other tissue
promotes protein synthesis
inhibits protein degradation
72
control of insulin secretion is _____ feedback based on:
negative
serum glucose and amino acids, GI hormones, parasympathetic activity like when you eat a meal..the presence of glucose, amino acids, or fatty acids stimulates the pancreas to secrete insulin
73
Glucagon is secreted by ______ and function:
pancreatic alpha cells
glucagon raises blood glucose levels by stimulating the liver to metabolize glycogen into glucose molecules and to release glucose into the blood
74
glucagon promotes/stimulates what processes:
promotes glycogenolysis
stimulates gluconeogenesis
promotes fat breakdown
75
epinephrine, cortisol, and growth hormone do what to blood AA and muscle protein?
all increase glucose and fatty acids
cortisol increases blood amino acids and decreases muscle protein
GH decreases blood AA and increases muscle protein
76
metabolism definition:
| nutrients are used by all cells to:
- organized process though which nutrients like proteins, fats, and carbs are broken down, transformed or otherwise converted into cell energy
- synthesize large quantities of ATP
77
ADP is converted to ATP by :
the energy gained from the oxidation of carbohydrates, proteins, fats; ATP is then consumed by various reactions necessary to cell function
78
Calorie or kilocalorie=
1000 small calories which is the energy required to raise the temp of 1 kg of water by 1 degree celsius
79
final products of carbohydrate digestion are:
glucose (80%)
| fructose and galactose
80
after absorption from the intestines fructose and galactose are converted to _____, in the _______
glucose, liver
81
the liver stores glucose as glycogen by what process?
glycogenesis-glucose molecules are added to chains of glycogen for storage
82
What is released when quick energy is needed and acts on the liver and skeletal muscle?
epinephrine
83
what stimulates gluconeogenesis?
| what is gluconeogenesis?
serum glucagon levels
| synthesis of glucose from noncarbohydrate precursors
84
carbohydrate metabolism is the breakdown of:
breakdown of starches and sugars into smaller units to be used for energy..glycogen storage
85
in fat metabolism, almost all the fats in the diet are absorbed into the intestinal lymph via _________.
what do these empty into?
chylomicrons empty into the juncture of the jugular and subclavian veins
they are removed from the blood in the adipose tissue and liver by lipoprotein lipase
86
when carbs are down, lack of _______, reduces the rate of glucose use and increases fat metabolism
insulin
87
epi, norepi, corticotropin, glucocorticoids and growth hormone activate _____?
what hormone can cause rapid mobilization of fat?
1. hormone sensitive triglyceride lipase
| 2. thyroid hormone
88
protein metabolism is when:
proteins are broken down into amino acids in the GI tract and absorbed into the blood
-most of the AA in the blood enter the cells and form new proteins but a pool of free AA exists in the blood as well as plasma proteins
there is constant equilibrium between the cell proteins, free AA, and plasma proteins
89
when cells have reached limit of stored proteins.......
excess AA are degraded in the liver and used for energy or stored as fat or glycogen
90
growth hormone _______ synthesis of cellular proteins and _______ glucose release and uses fatty acids for energy
increases, decreases
91
glucorticoids ______ proteins in the tissue
decrease
92
testosterone _____ protein in the tissue
increases
93
BMI is a measurement of what?
body fat based on height and weight ratio
applies to ages 18-65
BMI is a persons weight in kg divided by the square of height in meters
94
healthy BMI
overweight BMI
Extremely obese
18-24
25-29
>39
95
recommended daily allowances (RDA)
| purpose?
define the intakes that meet the nutrient need of almost all healthy persons in a specific age and sex group
purpose is to advise clinicians and the general public about the level of vitamin and nutrient intake necessary to prevent disease
