Adaptation to cold, heat and altitude new 2-2
Larsen 2016
Biological adaptation
- Physical. Genetic. Temporary acclimatization
Cultural
- Clothing. Fire. Institutions - fishing in coastal areas. Tools mesolithic.
Heat
- Body has to maintain 37 degree Celsius.
- Increased sweating. Hypothalamus regulates thermal condition of body.
- Diagram Hot. Sensor send impulse to hypothalamus. Hypothalamus increases heart rate. Increased vasodilation. Heat loss through skin in and sweat. Long-term acclimatization reduce core temperature
- Genetic adaptation. Body shape and size. Narrow body long limbs. Alan bergmann's rule related to trunk size. Allen Bergman rule. long fingers limbs ears stores dissipate large amount of heat from body. Found in Africa Sahara tribes. Dark skin to reduce sunlight effect.
- Cultural adaptation. Housing. Cotton clothes. Water storage. Restricted afternoon activity.
Cold
- Goal is to stop heat loss from body.
First exposure. Vasoconstriction. Shivering. Reduced blood flow to extremities
- Gradually. Reduced great rate. Higher metabolism. Higher skin temperature than non adapted persons.
- Genetic change. White body. Short limbs. Subcutaneous fat distribution changes like in eskimos
- Large body size to reduce surface area and loss of heat bergmann's rule
- Short limbs Allen rule
- Cultural adaptation. Igloo. For clothing. Fire. Diet changes.
High altitude. low atmospheric pressure and lack of oxygen available.
- First exposure. Hypoxia. Medula oblongata simulation and higher breathing. Nausea. Headache. Heavy breathing. Hypoxia. Loss of appetite. Fatigue.
- Little 1979. Hypoxia starsat 2000.
- Bekar 1969 study of low altitude natives migrating to high altitude Adapt to the stress by consumption of less oxygen. Decrease of 24% in USA whites and 10% in Quechaa Indians
- Functional adaptation. greater diameter of arteries and veins and greater flow of blood to the tissues. Greater long volume. Efficient oxygen usage. Largest chest. Kidney stimulation secretion of erythropoietin which increases red blood cells and HB. Increased lung surface.
- Genetic change. Higher oxygen saturation in blood. People of Andes and Tibet. Tibet have EGLN1 & EPAS1 genes for oxygen homeostasis in higher altitude. Greater ratio of ventilatory capacity to body mass. Reduce body size. Short nose to reduce muzzle passage.
- Cultural adaptation. Brazilian highlanders herbal leaves to increase HB level. Rich diet. Active lifestyle.
Christopher ruff. American physical Anthropology define the concept of human morphology. He discovered that adaptation to heat and cold is not related to person's height but more important is width of the body trunk because ratio of surface area to body mass is maintained regardless of the height. People living in cold areas have wider bodies and heat areas have longer tibia
A diagram from sir notes.