Biology paper 2

• What is homeostasis?

  Regulation of internal conditions despite external changes
• Why is homeostasis important?

  It allows crucial chemical reactions to occur optimally
• What three internal conditions does the body regulate?

  Blood glucose concentration, temperature, water levels
• How does the nervous system help maintain homeostasis?

  By sending signals to effectors based on stimuli
• What are the two main parts of the nervous system?

  CNS and PNS
• What does the CNS consist of?

  Brain and spinal cord
• What is the role of receptors in the nervous system?

  To detect changes due to stimuli
• What is a reflex arc?

  A pathway that bypasses the brain for quick responses
• What is the function of glands in the body?

  To produce specific chemicals as needed
• How can you investigate reaction times?

  By dropping a ruler and measuring the distance
• What is the formula to calculate reaction time from distance?

  $t =$$\sqrt{\frac{2d}{g}}$
• What is the role of the brain in reaction times?

  To process signals and make conscious decisions
• What are the three parts of the brain?

  Cerebral cortex, cerebellum, medulla oblongata
• What does the cerebral cortex control?

  Higher-level functions like memory and speech
• What is the function of the cerebellum?

  Motor skills, movement, balance, coordination
• What does the medulla oblongata control?

  Unconscious actions like heart rate and breathing
• What is MRI used for?

  To safely see brain activity
• What is accommodation in the eye?

  Ability to change lens shape for focus
• How does the eye focus on distant objects?

  Ciliary muscles relax, lens becomes thin
• How does the eye focus on near objects?

  Ciliary muscles contract, lens becomes thick
• What is the function of the pupil?

  To change size based on light intensity
• What is the cornea?

  Transparent outer layer of the eye
• What do rods in the retina detect?

  Light intensity, not color
• What do cones in the retina detect?

  Color wavelengths: red, green, blue
• What is myopia?

  Shortsightedness, can't focus on distant objects
• What is hyperopia?

  Longsightedness, can't focus on near objects
• How do glasses correct vision?

  By converging or diverging light before entering
• What is thermoregulation?

  Control of internal body temperature
• How does the body respond when too hot?

  Sweating and vasodilation occur
• How does the body respond when too cold?

  Shivering and vasoconstriction occur
• What is the endocrine system?

  A system of glands producing hormones
• What is the main gland in the endocrine system?

  The pituitary gland
• What does the pancreas produce?

  Insulin to regulate blood glucose levels
• What happens when blood glucose is too high?

  Pancreas secretes insulin to lower levels
• What happens when blood glucose is too low?

  Pancreas produces glucagon to raise levels
• What is type 1 diabetes?

  Pancreas can't produce enough insulin
• What is type 2 diabetes?

  Cells no longer absorb glucose properly
• What is the role of kidneys in water balance?

  To remove excess water and filter blood
• What is ADH?

  Antidiuretic hormone that regulates water reabsorption
• What is negative feedback?

  Response that returns conditions to normal