Cold

Question 0

What are the human responses to cold?

Answer 0

Vasoconstriction
Shivering
Pilo-erection

Question 1

What is the major heat loss problem for humans at cold air temp?

Answer 1

Convection

Question 2

What affects the severity of effects from the cold?

Answer 2

Severity and duration of cold
Accompanying exercise
Magnitude of metabolic response
Individual characteristics hw body composition, age and gender

Question 3

What can effect body tempterature?

Answer 3

Oestrus cycle at ovulation
Fever
Aspirin ( lowers set point)
Exposure to hot environment raises set point
Shivering
Behaviour

Question 4

What does increased sympathetic activity lead to?

Answer 4

Vasoconstriction and Pilo erection

Vaso constriction also leads to raised blood pressure

Question 5

What are the 2 types of shivering

Answer 5

Ordinary- due to cite temperature dropping

Violent- skin temp suddenly cooled

Question 6

Why do people doe of hypothermia?

Answer 6

Ventricular fibrillation and asystole

Question 7

What is the spectrum of disuse?

Answer 7

Reduced activity
Bed rest/microgravity
Casting
Spinal cord injury

Question 8

What are the common methodological approaches to study disease?

Answer 8

Limb suspension
Bed rest
Microgravity
Muscle biopsy
Imaging (MRI)
Functional tests

Question 9

What is orthostaric hypotension?

Answer 9

Shift in blood when changing from lying supine to standing
0.5l can shift from chest to legs
Carotid and aortic baroreceptors detect fluid shift as reduction in pressure.
Initiates vaso and venoconstriction
All to maintain BP and cerebral perfusion

Question 10

What is central shift?

Answer 10

Change in blood distribution from standing to lying
0.5l from legs to central thorax
Carotid and aortic baroreceptors detect fluid shift as increase in pressure and increased SV due to increased pre-load
Initiates vaso and venoconstriction, decreased HR and contractility & diuresis

Question 11

Causes of decreased VO2 with bed rest?

Answer 11

Reduced SV= reduced CO2 
Reduced venous return
Venous compliance causes pooling of blood in legs
9% decrease in RBC mass
Decreased muscular capillarisation

Question 12

Gender differences of muscle strength loss due to bed rest?

Answer 12

Women lose similar amount but more strength

Question 13

What is disuse osteoporosis?

Answer 13

Reduced weight bearing causes increased resorption of bone minerals and this, reduced bone mineral density
Evident as thinning on trebacular bone

Question 14

Cardiac problems following immobilisation

Answer 14

HR increase by 3-15bpm in 4 weeks
Blood vol decreases 5% within 24hr and 20% in 2 wks
SV decrease
Left ventricular atrophy
Fluid shifts
Orthostatic hypotension
Risk of blood clotting and embolism
Decreased VO2 Max

Question 15

Why do muscles lose size and function?

Answer 15

Maintaining muscle fibres and connective tissue in shortened position leads to loss of sarcomeres in series and tightening if dense connective tissue
This causes loss in RoM
cartilidge and synovial fluid can degenerate and fat tissue infiltration leads to problems in the joint