Block 8 Exam Flashcards
Flailing injuries
Injuries sustained due to lack of arm or leg restraints or ejection at high air speed
Skeleton G suit
abdomen down
Full coverage G suit
Feet up
Maximum daily exposure without Active noise reduction
Can be exceeded in as little as half an hour
Why can’t sunscreen be used in the cockpit
Can’t apply frequently enough
Can degrade the mask
Can be flammable
Three shunts in fetal circulation
Ductus Arteriosus
Foramen Ovale
Ductus Venosus
Ductus Arteriosus
Pulmonary artery => aorta
Foramen ovale
Right atrium => left atrium
Ductus Venosus
Bypasses liver
Organogenesis time
4-16 weeks
Organogenesis
Formation of major airways
Formation of bronchial tree and portions of respiratory parenchyma
Birth of the acinus
Differentiation time
16 weeks - birth
Airway liquid clearance
Na+ reabsorption before birth
Mechanical forces During vaginal delivery
Pressure gradients of first breaths after delivery
Pulmonary complications for preterms
Smaller diameter airways
Reduced airway surface area
Lack of effective surfactant
Surfactant production
Begins around 26 weeks
Manifestations/symptoms of neonatal respiratory distress syndrome
Tachypnnea Grunting Nasal flaring Chest wall retractions Increasing FiO2 requirement
How do infants maintain thermoregulation?
Non-shivering thermogenesis
Vasoconstriction
Sweating
Risks for hypothermia in neonates
Larger surface area relative to body mass
Little white fat for insulation
Thin skin
Extended posture
Increased oxygen consumption to maintain thermic stability
Limited stores of BAT
Periventricular leukomalacia
Major form of cerebral white matter injury affecting preterm infants
White matter damage due to hypoxic-ischemic injury
Percent of time spent wave riding
3-5%
Percent of time spent paddling
40%
Percent of time spent stationary
50%
Percent of time spent miscellaneous
10%
Role of wetsuits
Insulation Injury prevention Performance Proprioception Energy expenditure
Access points of wetsuits
Neck
Zipper
Cuff regions of arms
Ankle
Fluid loss during surfing results
Surf duration and body composition significantly correlated with fluid loss
Body weight lost in costa rica
0.98%
Body weight lost in Australia
0.94%
Body weight lost in San Diego
0.48%
Utilization of Surf apparel to dissipate heat during surfing
No significant difference found in skin temperature between wearing surf shirt, rash guard, or no shirt
Where in the body do surfers lose heat?
Thigh, calf, and abdomen
Where did surfers feel coldest
Calf, forearm, and chest
Where did surfers feel most uncomfortable
Chest
Where did surfers feel wettest
Lower legs, chest, upper back, lower back, and wrist
Smoothskin in the field
Upper chest, back, and lower back were significantly warmer
Smoothskin in the lab
Upper chest and lower back were found to be significantly warmer
Silicone in the field
No statistical significance in upper chest, upper back, and lower back
Abdomen was statistically significantly colder
Silicone in lab
Significantly warmer in upper back
Colder in abdomen
Thermo light
No statistical significance
Graphene
Significantly colder than standard fleece in lower back
Thermoplastic Elastomer (TPE)
Significantly colder in upper chest, lower arm, lower abdomen, upper leg, lower back, lower leg compared to polychloroprene foam
Class A Mishaps
Spatial Disorientation/Illusions/Misperceptions Fatigue Medications/Illnesses Loss of consciousness Diet/Nutrition Hypoxia Heat/Cold/Dehydration
G force
Measure of acceleration where 1 G is the force of gravity on the body
Gravitational force experienced during acceleration and/or change in direction
Gy axis
Left to right
Gx axis
Front to back
Gz axis
Top to bottom
Air plane turns right G force
+Gy
Air plane pitches up
+Gz
Air plane accelerates on runway
+Gx
For every 1G BP above heart decreases by
22 mmHg
FiO2
0.21
Patm at sea level
760 mmHg
PH2O at sea level
47 mmHg
PaCO2 at sea level
40 mmHg
RQ value
0.8
For every ___ m dive absolute pressure increases by ___ atm
10
1
Nitrogen Narcosis
Increase PN2 causes N2 to dissolve into blood and tissues
Causes effects resembling alcohol intoxication
Martini’s Law
15m of descent = 1 martini
Decompression sickness
Happens when diver returns to surface too quickly after deep dive
Treatment for decompression sickness
Recompress in hyperbaric chamber
PB falls by ___ for each ____ of ascent
1/2
~5500m
Acute adaptations to hypoxia
HVR Hyperventilation Increased HR and CO Decreased food intake Increased bicarb excretion Decreased H+/acid excretion Right shift begins
Long term adaptations to hypoxia
Increased ventilation Bicarb excretion Oxidative enzymes increased Increased pulmonary diffusing capacity Increased HIF-1 Increased HCT Right shift Weight loss Decreased core temperature
HVR PAO2
Enhanced by 10-12 mmHg
Tibetans
Show HVR
Similar to “pink puffer”
Bolivians
Do not show HVR
Polycythemia
Similar to “blue bloater”
Acute mountain sickness symptoms
Nausea
Headache
Sleep disturbance
Lassitude
Acute mountain sickness treatment
Descent CO2 Acetazolamide O2 Dexamethasone
High-altitude cerebral edema treatment
Descent
Chronic mountain sickness symptoms
Headache Confusion Sleeplessness Cyanosis Erythemic conjunctivae due to excessive polycythemia
Chronic mountain sickness treatment
Descent
Phlebotomy
Gray out
Loss of blood flow to retina
No loss of consciousness
Orthostatic hypotension
Black out
Loss of blood flow to brain
Loss of consciousness
White out
Hypoxia
No loss of consciousless
Red out
Red vision
Loss of consciousness
Body temperature 40-44
Heat stroke with multiple organ failure and brain lesions
Body temperature 38-40
Hyperthermia (as a result of fever or exercise)
Body temperature 36-38
Normal range
Body temperature 34-36
Mild hypothermia
Body temperature 30-34
Impairment of temperature regulation
Body temperature 27-29
Cardiac fibrillation
Diagnosis of CO poisoning
CO-oximetry
Arterial blood gas
Treatment of CO poisoning
High-flow O2 to increase PAO2
Hyperbaric chamber to increase PaO2
Endotherms
Generate the heat they need internally
Ectotherms
Body temperature depends on external heat sources
Homeotherms
Maintain stable body temperature by generation heat generally above external temperature
Mesotherms
Express characteristics and both endotherms and ectotherms
Poikilotherms
Do not regulate internal body temperature and rely on external environment
Large S:V ratio
Small animal
Lose a lot of heat
Increased metabolism
Bergmann’s rule
Bigger animals are better for a colder environment
Core body temp varies based on:
Time of day
Physical activity
Time in menstrual cycle
Age
Anterior hypothalamus regulation of body temperature
Responds to increased core temp
Sweating and increased skin blood flow
Posterior hypothalamus regulation of body temperature
Responds to decreased core temp
Shivering, decreased skin blood flow, nonshivering thermogenesis
Resting metabolic rate influenced by
Sex Body size Fat Age Hormones Fitness level Temperature
Positive S value heat balance equation
raises core temp
Negative S value heat balance equation
Lowers core temp
Radiation
Transfer heat via infrared rays
Conduction
Heat loss due to contact with a surface
Convection
Heat transferred to air or water
Evaporation
Heat from skin converts water to water vapor
Motor unit
A single alpha motor neuron and all muscle fibers that it innervates
Motor neuron pool
All alpha motor neurons that innervate a single muscle
Innervation ration
alpha motor neurons: # muscle fibers
Smaller ratio in fingers
Larger ratio in gastroc muscle
Type I (slow twitch)
Membrane resistance is high
Small diameter neurons
Smaller motor units
Type II (fast twitch)
Membrane resistance is low
Large diameter neurons
Larger motor units
Force of contraction depends on:
of motor units recruited
Size of motor units
Frequency of motor neuron firing
Muscle and sarcomere stretch
Henneman’s Size Principle
Type I -> Type IIa -> Type IIx
of mitochondria Type I
High
of mitochondria Type IIa
High/moderate
of mitochondria Type IIx
Low
Fatigue resistance Type I
High
Fatigue resistance Type IIa
High/moderate
Fatigue resistance Type IIx
Low
Major energy source Type I
Aerobic
Major energy source Type IIa
Combination
Major energy source Type IIx
Anaerobic
ATPase activity Type I
Low
ATPase activity Type IIa
High
ATPase activity Type IIx
Highest
Speed of fiber shortening Type I
Low
Speed of fiber shortening Type IIa
High
Speed of fiber shortening Type IIx
Highest
Efficiency Type I
High
Efficiency Type IIa
Moderate
Efficiency Type IIx
Low
Specific tension Type I
Moderate
Specific tension Type IIa
High
Specific tension Type IIx
High
Innervation ratio Type I
Small
Innervation ratio Type IIa
Large
Innervation ratio Type IIx
Largest
Concentric contraction
Sarcomeres shortened
Force generated
Positive work
Eccentric contraction
Sarcomeres lengthened
Deceleration of force
Negative work
Instant Energy
10-15 seconds
Stored ATP and creatine phosphate
Type IIx
Short-term energy
15 seconds - 2-3 minutes
Anaerobic metabolism of glucose
Type IIa
Long-term energy
2-3 minutes and beyond
Aerobic metabolism of glucose, fatty acids, and some protein
Type I
VO2 max is dependent on:
Cardiac output
Oxygen delivery
Oxygen diffusion
Factors contributing to fatigue
Motivations
Physical fitness
Nutritional status
Types of motor units recruited
Recovery after exercise affected by
Fitness level
Temperature and humidity
Intensity and duration
Central fatigue
Changes in CNS
Peripheral fatigue
At the level of the muscle fiber
Apocrine sweat glands
Produce viscous secretions
No role in temperature regulation
Eccrine sweat glands
Innervated by cholinergic sympathetic nerves
Secrete and reabsorb water and solutes
Regulate temperature
Senescence/Aging
Progressive changes during adult life that underline an increasing vulnerability to challenges faced by the organism
Primary aging
Intrinsic changes occurring with age, unrelated to disease or environmental influences
Secondary aging
Changes caused by the interaction of primary aging with environmental influences or disease processes
Frailty
A pathologic geriatric syndrome characterized by high susceptibility, impending decline in physical function and high risk of death
Hypotheses of aging mechanisms
Mutation-accumulation mechanism
Antagonistic pleiotropy
Disposable Soma theory
Mutation-accumulation mechanism
Mutated genes that don’t have deleterious effects until advanced ages
Antagonistic pleiotropy
Genes with deleterious actions late in life increase evolutionary fitness in early adulthood
Aging is a byproduct of natural selection
Disposable Soma theory
Purpose of an organism is to procreate
Cellular and molecular mechanisms of aging
Damage caused by oxidative stress and other factors
Inadequate repair of damage
Dysregulation of cell number
Dysregulation of homeostasis of cell number
Hyperplasia, Neoplasia, or atrophy
May be caused by decreased telomere length
Hyperplasia
Increased number of cells
Hypertrophy
Increased size of cells
Neoplasia
New cell/mass growth
Atrophy
Decline/shrinkage of tissue
Oxidative stress theory
Free oxygen radicals damage important molecules
Glycation theory
Formation of advanced glycation end products which can induce DNA damage
Mitochondrial theory
Damage to mitochondrial DNA form ROS => Less ATP generation => Loss of cell function => aging
DNA Damage theory
DNA damage is produced by radiation, ROS, making it lose the ability to repair itself
Necrosis
Response to severe cell trauma
Unregulated
Apoptosis pathways
Extrinsic
Mitochondrial
Nuclear
Extrinsic apoptosis pathway
Extracellular signals activated internal caspase cascade => proteolysis
Mitochondrial apoptosis pathway
Damage to mitochondria => release cytochrome-c => cell committed to apoptosis
Nuclear apoptosis pathway
Activation of P53 => increased ratio of bax:bcl-2 => apoptosis
Gelsolin
Breaks down actin marking cell for death
MPTP
Mitochondrial permeability transition pore
BAX
Pro-apoptosis
BCL-2
Prevents apoptosis
GFR in aging
Decreases in some older adults
Bladder in aging
Increase in urgency, frequency, and nocturia
Pulmonary function in aging
Loss of collagen and elastin structure
Exercise capacity in aging
Decreased VO2 max
Cardiovascular system in aging
Decreased arterial compliance
Bone in aging
Resorption > formation
Skin in aging
Thins and becomes less elastic
Endocrine system in aging
Decline in many hormone levels (exception = PTH)
Body mass in aging
Loss of lean mass
Increased fat mass
Brain in aging
White matter loss
Sarcopenia definition
Age-associated loss of skeletal muscle mass and function
Sarcopenia
Loss of number and size of muscle fibers
Progressive loss of innervation of motor units
Slowing aging process in animals
Eat less food (caloric restriction)