homeostasis

How organisms maintain their internal balance.

Homeostasis is not a process, it is a state.

• Internal environment: Temperature, blood, pressure, water concentration, glucose concentration.

  • It is necessary to keep an internal balance so that cellular reactions can occur accurately, and life can live.
  • The eventual consequence of the absence of homeostasis would be death.

  skin

  • Regulates temperature for correct enzyme work (human enzymes work best at 37°C) and due to temperature receptors.
  • Senses temperature, pressure, and touch.
  • Protects from pathogens and radiation.
  • Radiation can easily cause unnecessary apoptosis.

  Skin structures:

  1. Hair y hair erector muscle:

     1. When we are hot it lies flat against the skin, permitting free air circulation and increasing radiation rates.
     2. When we are cold, hair erects so that it can trap a layer of air that insulates heat loss.

  2. Free nerve (sensitive to pain and temperature)

  3. Sweat pore and sweat gland:

     1. The sweat gland is identified as a nod connected to capillaries and ending on a pore which is the only exit.
     2. Sweat takes out salt and water from your blood.
     3. Sweat cools the skin by evaporation.

  4. Epidermis

  5. Dermis: Where touch and pressure receptors are located.

  6. Arteriole

  7. Fatty tissue / Adipose tissue: Insulates heat, retarding heat dissipation.

• When we are cold, skeletal muscles contract and we shiver. Plus, the energy needed to do this is sometimes released as heat.

  vasodilation and vasoconstriction

  When we are cold blood flow in capillaries reduces so that it is not so close to the surface where radiation is faster and easier, a process known as vasoconstriction.

  When we are hot blood flow is higher, so that capillaries and blood vessels dilate and blood flows closer to the surface where it can be transferred more accurately. That is also the reason why in a hot environment our cheeks become red. This event is known as vasodilation.

  other organs

• If one organ fails to maintain homeostasis, then homeostasis as a whole is lost too, to the complexity of connections starting from the blood in an organism’s body.

  negative and positive feedback

• A very clear example of what a failed homeostasis looks like is diabetes type 1. Patients are advised to take insulin, as the body itself cannot produce enough to regulate the needed glucose and convert the excess into glycogen.