Bio 2

• What is homeostasis?


  The regulation of internal conditions to maintain optimum conditions
• State the three steps in control systems

  Receptors

  Coordination centre

  Effectors
• What are receptors?


  Specialised cells which detect stimuli
• What is an effector?


  A muscle or gland that carries out a response to a stimulus.
• What are nerve cells referred to as?

  Neurones
• What is the central nervous system made up of?

  Brain and spinal cord
• What is the peripheral nervous system made of?

  All of the neurons outside of the brain and spinal cord
• State the steps in the reflex arc

  Stimulus

  Receptor

  Sensory neurone

  Coordinator

  Motor neurone

  Effector

  Response
• What is a stimulus?


  A change in the environment
• What is a synapse?

  Gap between two neurones
• Why are reflex actions important?

  Their automatic and rapid and don’t involve the conscious part of the brain.

  This helps to keep us safe
• What does the cerebral cortex control?

  Consciousness

  Intelligence

  Memory

  Language
• What does the cerebellum control?

  Coordination of muscular activity
• What does the medulla control?

  Controls unconscious activities such as heartbeat and breathing
• What is the eye?

  Sense organ which contains receptors which are sensitive to light intensity and colour
• What do cone cells in the eye detect?

  Colour
• What do rod cells in the eye enable us to do?


  See in dim light
• What is the function of the optic nerve?

  Since nervous impulses from photo receptors in the retina to the brain
• What is the function of the lens?

  Refracts light to the retina
• What is the function of the cornea?

  To refract light.
• what is the endocrine system?

  A system in the body made a specialised organs called glands which secrete hormones directly into the blood system
• What do hormones do?

  They are chemical messages secreted into the blood where they travel to a target organ where produces an effect in the body
• The nervous system is faster than the endocrine system
• Why is the pituitary gland called the master gland?

  It’s a secret several hormones which intern act on other glands in the body
• Which hormone is secreted if blood glucose gets too high?

  Insulin
• where is insulin secreted from?

  Pancreas
• What does insulin do?

  Regulates blood sugar levels.
• What hormone is secreted if blood glucose is too low?

  Glucagon
• What does glucagon do?


  Raises blood sugar levels.
• What causes type one diabetes?

  Pancreas fails to produce sufficient insulin
• What causes type two diabetes?

  The body cells no longer respond to the insulin produced by the pancreas
• How does water leave the body?

  Urination, sweating, breathing
• How do we gain water in the body?

  Food and drink and respiration
• What is ovulation?


  The release of an egg cell from the ovary
• What does oestrogen do?


  Initiates the menstrual cycle

  Increases body Hair

  Hips widen, and breasts develop
• What does FSH do?

  Stimulates egg cells to mature
• What does LH do?

  Stimulates ovulation
• What does progesterone and oestrogen do?

  Build up and maintain the uterus lining
• Where is adrenaline released from?

  Adrenal glands
• Where is thyroxine released from?

  Thyroid gland