Summary Questions

• What is an example of an effector?

  Muscles or glands
• What is the role of sensory neurones?

  To transmit sensory information to the central nervous system
• What is the role of a motor neurone?

  To carry signals from the central nervous system to effectors
• What should you do after answering all questions under a heading?

  Move on to the next section
• What is the purpose of a reflex action?

  • To protect the body from harm
  • To enable quick responses to stimuli
  • To bypass the brain for faster reaction
• What is the pathway of a reflex arc from stimulus to response?

  Stimulus → sensory neurone → relay neurone → motor neurone → effector
• What is the ciliary body's role in the eye?

  To control the shape of the lens for focusing
• What term describes an eye condition where a person can't differentiate between certain colors?

  Color blindness
• What structures should be labeled in a sketch of the brain?

  Cerebrum, hypothalamus, pituitary gland, medulla, cerebellum
• What is the function of the cerebrum?

  To control higher brain functions such as thought and action
• What is the function of the pituitary gland?

  To secrete hormones that regulate various bodily functions
• What are the two diffusions involved in investigating brain function?

  Oxygen and glucose diffusion
• What is the endocrine system?

  A system of glands that secrete hormones into the bloodstream
• What is one role of thyroxine in the body?

  To regulate metabolism
• How does negative feedback control the level of thyroxine in the blood?

  It reduces thyroxine production when levels are high
• What effect does adrenaline have on the body?

  It prepares the body for 'fight or flight' response
• Where is oestrogen produced and what is its role in reproduction?

  Produced in the ovaries; regulates the menstrual cycle
• Where is progesterone produced and what is its role in reproduction?

  Produced in the ovaries; maintains the uterine lining
• Where is FSH produced and what is its role in reproduction?

  Produced in the pituitary gland; stimulates follicle development
• Where is LH produced and what is its role in reproduction?

  Produced in the pituitary gland; triggers ovulation
• How does the combined pill prevent pregnancy?

  By inhibiting ovulation and altering the uterine lining
• How does one non-hormonal method of contraception work?

  Condoms prevent sperm from reaching the egg
• What are the pros and cons of using condoms as a non-hormonal method of contraception?

  Pros: Prevents STIs; Cons: Can break or slip off
• How do auxins make plant shoots bend towards the light?

  By promoting cell elongation on the shaded side of the plant
• What are the effects of ethene on plants?

  It promotes fruit ripening and leaf abscission
• How are plant hormones used to control plant growth?

  • Auxins: Promote cell elongation
  • Gibberellins: Stimulate seed germination
  • Cytokinins: Promote cell division
  • Abscisic acid: Inhibits growth during stress
• What is homeostasis?

  The maintenance of a stable internal environment
• Why is homeostasis important?

  It ensures optimal functioning of cells and organs
• How is body temperature reduced when you’re too hot?

  Through sweating and increased blood flow to the skin
• What are the roles of insulin and glucagon in controlling blood sugar levels?

  Insulin lowers blood sugar; glucagon raises blood sugar
• How can type 1 and type 2 diabetes be treated?

  Type 1: Insulin injections; Type 2: Lifestyle changes and medication
• How does the water potential of tissue fluid cause cells to shrink?

  By creating a hypertonic environment that draws water out of cells
• What should be labeled in a sketch of a kidney tubule?

  Bowman's capsule, proximal tubule, loop of Henle, distal tubule, collecting duct
• How does the brain respond to a fall in the water content of the blood?

  It triggers the release of antidiuretic hormone (ADH)
• How does the kidney respond to an excess intake of water?

  By producing more dilute urine