Homeostatis

Internal conditions in the human body must be controlled.

There are lots of things to control including

• Water
• C02
• Oxygen
• Ions (like salt)
• Sugar levels
• Temperature

Various parts of our body are fashioned to deal with all this and when conditions aren't right - our bodies respond.

Water

Water enters our body through food and drink. It is lost through.

• Sweat
• Breathing
• Urine

Water balance depends on the day's temperature.

 COLD: No sweat, more urine.Dilute.
HOT: More sweat, less urine.  Concenerature and skin response

Too HOT:

• Hair flat to remove insulating layer of air
• Lots of sweat too transfer heat to the environment and cool you down
• Blood vessels under skin widen
  • vasodilation - more blood flows near surface. Heat is radiated away and you are cooled down
•  Brain encourages you to take off layers

TOO COLD:

• Hair stands up providing insulating air layer
• Very little sweat
• Blood vessels constrict to retain heat vasoconstriction
• Shiver to generate heat
• Brain encourages to put on layers

Ions

The kidney is responsible for taking care of our ion content.

• Taken in when we eat food
• Excess which needs to be removed
• Kidneys remove excess ions from…