V - Special Topics Flashcards
Regulation of body temperature is mediated by the
hypothalamus
Detected T in the _____ is compared with the _____ T in the hypothalamus.
Skin - detected T, hypothalamus - set-point T
Mechanisms activated when detected T is < set-point T
Heat Generating
Mechanisms activated when detected T is > set-point T
Heat Loss
Temperature Regulation: Shivering, thyroid hormone production, piloerection, skin vasoconstriction (alpha-1), brown fat in babies (beta-3)
Heat Generating
Temperature Regulation: Sweating, skin vasodilation
Heat Loss
Temperature Regulation: Insulator
Fat
Temperature Regulation: Radiator System
Skin: cold - vasoconstriction, hot - vasodilation
Most of the body heat is lost in what way?
radiation > evaporation > conduction to air > conduction to objects
Pathophysiology of Fever
pyrogens → increased IL-1 (α & β), IL-6 → increased prostaglandins (PG-E2) → increased set-point T in the hypotalamus
Excessive sweating causing fainting
Heat Exhaustion
HIgh T causing tissue damage and impaired responses
Heat Stroke
High T secondary to use of succinylcholine and halothane
Malignant Hyperthermia - defective Ca channels (Ryanodine) in sarcoplasmic reticulum → hyperexcitable muscles, Tx: Dantrolene - muscle relaxant
Malignant hyperthermia is caused by _____ & _____.
succinylcholine, halothane
Malignant hyperthermia is treated with
Dantrolene - muscle relaxant
Energy Systems: Cell ATP,cell phosphocreatine
Phosphagen Energy System
Energy Systems: First 8-10 seconds
Phosphagen Energy System
Energy Systems: 100m dash, jumping, diving
Phosphagen Energy System
Energy Systems: Anaerobic, reconstitutes ATP and phosphocreatine
Glycogen-Lactic Acid System
Energy Systems: 1.3-1.6 minutes
Glycogen-Lactic Acid System
Energy Systems: Tennis, soccer
Glycogen-Lactic Acid System
Energy Systems: Aerobic, reconstitutes ATP and phosphocreatine, glycogen-lactice acid cycle
Aerobic System
Energy Systems: Unlimited as long as there’s energy supply
Aerobic System
Energy Systems: Long-distance marathon
Aerobic System
Energy Systems: Fats provide
50% of the energy needed after 3-4 hours
Basis for muscle endurance
Glycogen: 400g - muscle, 100g - liver
Best diet for muscle glycogen recovery
Carbo-Loading for 2 days
Increased muscle strength is due to
increased muscle mass
Exercise: Maximal breathing capacity
150-170L/min
Exercise: Pulmonary ventilation during maximal exercise
100-110L/min
Exercise: 50L/min of the breathing capacity is used to compensate for
exercise at high altitude, exercise under hot conditions, abnormalities of the respiratory system
Muscle blood flow increases up to ___ during strenuous exercise.
20x
Cardiac output increases during exercise by
Resting CO - 5L/min, Athletes - 30L/min, Non-athletes - 20L/min
At maximal exercise cardiac output is at __% and pulmonary ventilation is at __% of their maximum levels.
cardiac output - 90%, pulmonary ventilation 65%
Cardiac Output: resting → maximal exercise
Cardiac Reserve: athletes - 600%, non-athletes - 400%
Only __% of nutrient energy is converted to muscle work. The rest is released as _____.
25% - muscle work, heat
Occurs at T > 42°C during exercise, damages neurons and T-regulating centers, double the rate of all intracellular reactions
Heat Stroke
___ lbs of body weight (mostly water) may be lost in 1 hour of athletic activity.
10lbs
During exercise __ and __ are lost in sweat leading to nausea, cramps, etc.
Na, K
Sweat glands may acclimatize to hot and humid conditions because of _____.
aldosterone
Increases muscle strength and aggressiveness, may also cause MI, stroke, HPN, high LDL, low HDL
Testosterone (Roid Rage)
Amphetamines and cocaine can cause
V Fib, psychological effects
At high altitude oxygen molecules are _____ leading to _____ oxygenation.
farther apart, decreased oxygenation
Most important effect of high altitude
decreased mental proficiency - judgement, memory and motor movements are affected
One can experience drowsiness, nausea, mental/muscle fatigue, headache, nausea and euphoria at ___ ft
12,000 ft - similar to alcohol intoxication
One can experience twitchings and seizures at ___ ft
18,000 ft
One can experience coma or death at ___ ft
23,000 ft
Acclimatization to Low Oxygen
increased pulmonary veltilation, polucythemia, increased diffusing capacity of oxygen, increased vascularity of peripheral tissue, increased ability of cells to use oxygen
After a few minutes at high altitudes RR increases by ___.
1.6x
After a few days at high altitudes RR increases by ___.
5x
At high altitudes hematocrit, blood volume and hemoglobin _____ because of _____.
increase (polycythemia), hyppoxia-induced EPO
At high altitudes there is an increase in the enzyme _____ which increases _____ causing a shift to the _____ of the O2-Hgb dissociation curve.
BG mutase, 2,3 BPG, right
At high altitudes diffusing capacity of oxygen is increased by ___.
3x
Natural Acclimatization in High Altitudes
decreased body mass, increased chest size, larger heart and lungs, increased Hgb, better O2 utilization
At high altitudes acute pulmonary and cerebral edema are caused by _____.
Acute Mountain Sickness
At high altitudes pulmonary vasoconstrictionand R-sided HF are caused by _____.
Chronic Mountain Sickness
Unit of force equal to the force exerted by gravity
G-force
G-Force: Pushed against the seat, blood is shunted to the lower extremities, more dangerous
Positive
G-force: Blackouts, LOC, death at
+6-+10G
G-force: Vertebral fracture at
+20G
G-force: Pushed against the seatbelt, blood is shunted to the head
Negative
G-force: Causes red-out of eyes and transient psychotic disturbances
Negative
G-force: Death at
-20G
The constant speed that a free-falling eventually reaches
Terminal Velocity
A skydiver would reach terminal velocity due to air resistance after _____ with a speed of _____.
12 seconds, 175 ft/s
Oxygen supplementation in space
20% O2 at 760 mmHg
Chronic effect of loss of gravity
deconditioning
Acute Effects of Space Travel
motion sickness, translocation of fluids, diminished physical activity
Chronic Effects of Space Travel
Decreased blood volume, RBC, muscle strength, maximum cardiac output, Ca & P from bones
High pressure air used by divers may lead to toxicities from high _____, _____ and _____ pressures.
nitrogen, oxygen, carbon dioxide
High Nitrogen Pressure: Joviality
120ft - like laughing gas
High Nitrogen Pressure: Drowsiness
200-250ft
High Nitrogen Pressure: “Raptures of the Depths”
> 250ft - alters ionic conductance in brain cells, increases nitrogen
Breathing oxygen at ____ will cause sudden seizures followed by come because of _____.
4atm, free radicals
High _____ pressure happens only if a diving apparatus malfunctions but can lead to severe respiratory acidosis, lethargy and narcosis.
carbon dioxide
Pathophysiology of Decompression Sickness
sudden ascent → formation of nitrogen bubbles → blocks blood vessels
Decompression Sickness: Pain in the joints and muscles
bends
Decompression Sickness: Dyspnea
chokes
Decompression Sickness: Chronic
Caisson’s Disease
Decompression Sickness: Treatment
US Navy decompression tables, tank decompression, use helium in very deep dives (> 250ft)
