The brain, central nervous system and thermoregulation

• The brain is made of billions of interconnected cells called neurones
• The cerebral cortex is the folded outer layer of the brain
• The cerebral cortex controls emotions, language, memories and conscious thought.
• The cerebellum is located at the back of the brain and controls balance and voluntary movements.
• The medulla is located at the top of the spinal cord.
• The medulla controls unconscious activities(things we do without

  thinking about them) such as controlling the  heartbeat, breathing and swallowing.
• Brain function must be investigated in living animals.
• damage to the cerebellumcan lead to loss of movement.
• Electrically stimulating a specific part of the brain can cause a specific reaction in the body.
• electrical stimulation of themedulla can cause hiccups
• Brain function can be investigated by studying the symptoms of patients with brain damage, electrically stimulating different parts of the brain, and using magnetic resonance imaging (MRI).
• MRI produces detailed images of the brainand its blood flow
• The thermoregulatory centre monitors and controls body temperature
• The thermoregulatory centre is found in a part of the brain called the hypothalamus
• The thermoregulatory centre contains receptors that detect the temperatureof the blood
• The thermoregulatory centre also receives nervous impulses from temperature receptors in the skin.
• The thermoregulatory centre sends information to effectors.

  These effectors respond to help the body warm up or cool down.
• Blood vessels, sweat glands and skeletal muscles respond to information from the thermoregulatory centre.
• When body temperature is too high, effectors help to transfer heat energy from the skin to the environment
• Heat energy is transferred to the environment when blood vessels in the skin widen or dilate (vasodilation).
• Heat energy is also transferred to the environment when sweat glands producesweat and it evaporates from the skin.
• When body temperature is too low, effectors respond to reduce heat loss.

  Heat loss is reduced when blood vessels in the skin narrow or constrict(vasoconstriction).
• Sweating stops to reduce the heat lost by evaporation from the skin
• Shivering is the rapid contraction of skeletal muscles.

  Shivering generates heat because it releases more energy from respiration.
• Receptors in the skin are sensitive to pain, pressure, touch and temperature.
• When the body becomes too cold, blood is diverted from the limbs to the core to decrease heat loss.
• The cerebral cortex is responsible for conscious thought. It occupies a large part of the brain and is highly folded.
• Vasoconstriction is a process that occurs in response to the body becoming too cold. The changes it brings about result in less heat being lost from the body and the temperature being returned to normal.
• The receptors in the thermoregulatory centre of the brain directly monitor changes in the temperature of the blood as it flows past them on its way around the body.
• Temperature receptors are located in the brain and the skin.