paper 2 based

• how does the thermaregulatory centre send information to the sweat glands in the skin?

  via nevres/neurones
• why does the skin appear red?

  dilation of blood vessels
• how does blood enter the kidneys?

  filtration
• why is glucose not found in the blood?

  reabsorption
• how is urine removed from the body?

  excretion
• describe the advantages and disdvantages of having a kidney transplant instead of dialysis?(4)

  Advantages: Improved quality of life, no need for regular dialysis sessions, flexible lifestyle, no need to control diet, cheaper for the NHS Disadvantages: Risk of rejection, need for lifelong immunosuppressant medication, donor may not be available, risk and recovery of surgery , may not last a long time
• which organ produces urine?

  Kidneys
• why do runners drink sports drinks?

  to replace the ions / water / salt lost during sweat
• which organ monitors body temperature?

  the brain
• describe how to body responds when theres a decrease in corer body temperature (6)?

  • blood vessels supplying the skin with blood constrict ( vasoconstriction)
  • less blood flow through capillaries to the skin so less energy is lost
  • shivering by muscle contraction respiring more to release more energy
• how does the eye refract more light?

  by becoming thicker
• which 2 structures control the shape of the eye?

  ciliary muscles and suspensory ligaments
• what must the eye focus light on?

  the retina
• what is a reflex action?

  an automatic response/action that needs no thought behind it
• describe how the body reacts when you touch a hot object?(6)

  • receptor in the finger/skin/hand detects the stimulus/ temperature change
  • electrical impulses pass through the neurones - sensory to relay to motor
  • synapse between the neurones where chemicals cross gap
  • synapses in the spinal cord/CNS
  • effector is a muscle and contracts to pull away
• give three ways the endocrine system is different to the nervous system?

  coordination by the endocrine system is SLOWER, LONGER LASTING AND TRANSFERS HORMONES instead of electrical impulses via neurones
• describe how hormones control the menstrual cycle (5)?

  1. FSH released from pituitary stimulates follicle maturity
  2. oestrogen released from the ovary inhibits FSH production and stimulates LH production
  3. LH released from the pituitary stimulates ovulation
  4. progesterone released from the ovary inhibits both FSH and LH production
  5. oestrogen and progesterone maintain uterus lining
• which part of the brain controls balance?

  cerebellum
• what is the brain?

  a coordinator
• what type of cell carries impulses?

  neurones
• what happens when you look up from whatever you were looking at below e.g from looking at a book to trees

  light rays refract less
• what is myopia?


  Nearsightedness
• what is hyperopia?


  Hyperopia is a refractive error of the eye that causes distant objects to be seen more clearly than nearby objects.
• what is the function of the cerebral cortex?


  Higher cognitive functions, such as perception, memory, language, and decision-making.
• suggest how an MRI scanner can detect what kind of brain damage someone has?

  • can ask people to perform different activities during the scan to see which part of the brain is active/inactive
  • compare with someone who doesnt have brain damage and find out where the damage is located
  • traditional MRI scanner can be used if someone doesnt stay still
• how does the brain recieve information about light entering the eye?

  cells/ receptors in the retina are sensitive to light , impulses pass along sensory neurone along the optic nerve
• explain how birds who can detect UV light have evolved from birds who cant (6) ?

  1. mutation in gene/dna can be random or by chance
  2. causes different protein to be made therefore creates variation in the wavelengths of light the birds can detect
  3. birds with the mutation are more likely to see the food and where mammals have been
  4. therefore get more food and avoid being eaten by animals
  5. most successful competitor survives, the others die out by natural selection as it is the survival of the fittest
  6. breed/reproduce and pass the allele to offspring over many generations
• describe things to imrpove during metre ruler catching test?

  more repeats with different students with a more precise scale on the ruler , drop from the same height
• explain how the persons eye can adjust to form a clearer image of a nearer object (6)?

  1. ciliary muscles contract and have a smaller diameter, suspensory ligaments loosen/slacken so lens becomes thicker/fatter/curved
  2. lens is more convergent and light rays focus on the retina
• why does a person with hyperopia find it hard to see nearer objects?

  eyeball is too short the light focuses behind the retina
• descibe how spectacle lenses can help hyperopia?

  convex lens makes light rays refract more and focuses them on the retina
• suggest why reaction time ith a computer is more accurate than a stopwatch?

  milliseconds cant be measured with a stopwatch
• why did a student measure 10 reaction times rather than 3?

  increased validity/repeatability to get represantative results because of the variation
• what is the effect of caffiene on reaction time?

  reduces reaction time
• what happens to eyes during dim lighting?

  • pupils dilate at dim lights because circular muscles in the iris relax and radial muscles contract
• why is it more dangerous for older people to drive cars?

  older people have a slower reaction time therefore have a higher risk of getting into an accident
• describe the difference between the function of an effector vs a receptor?

  Effector: Responds to signals, produces a response and is a muslce or gland Receptor: Detects stimuli, receives signals can be retina
• what is a synapse?

  junction between neurones
• how are chemicalss transmitted?

  diffuse
• what does urea contain a lot of?

  protein