Paper 2 Bio

• Thyroxine


  Hormone that regulates rate of metabolism
• Diabetes


  • Type 1 diabetes - occurs in childhood/teenage years, pancreas doesn't produce insulin or not enough, treated with injected insulin
  • Type 2 diabetes - occurs in older people, cells become resistant to insulin, treated with healthy diet and exercise
• Kidney function


  1. Filter blood

  2. Remove waste (urea)

  3. Regulate water balance
• Water regulation is important because cells can lose or gain water by osmosis, leading to shrinking or swelling/bursting if water levels are too high or low
• Homeostasis


  Maintenance of internal environment in response to internal and external conditions
• Nervous system


  • Electrical signals through nerve cells
  • Precise
  • Fast
• Endocrine system


  • Hormones released from glands to bloodstream
  • Long-lasting
  • Slower
  • Generalized
• Homeostasis consists of …

  1. Receptors detect the change

  2. Coordination centre (brain, spinal cord)

  3. Effectors (muscles, glands) carry out the change
• Neuron


  Biological wire that carries small current
• Neuron


  • Long
  • Thin
  • Nucleus
  • Dendrite
  • Axon terminals
• Synapse


  Gap between neurons
• Transmission of electrical impulse (message)

  1. Travels along the axon

  2. Arrives at the terminal (end) of the axon

  3. Chemical (Neurotransmitter) is released

  4. Chemical diffuses across the synapse (gap) and binds with receptor molecule on the other neuron
• Receptors only bind to…? 


  a specific Neurotransmitter released, which stimulates the neuron to transmit an electrical impulse along its axon
• Motor neuron carries message to the effector
• Hormone that stimulates Thyroid to release thyrione?

  Pituitary Gland
• Chemicals produced by endocrine glands are called HORMONES
• The hormones travel through blood vessels to target cells/organs where they have their effects.
• Target cell has RECEPTOR proteins on its surface or inside it that can bind to the hormone.
• ADH (Anti-Diuretic Hormone)


  Hormone that causes the kidneys to produce less water and more concentrated urine
• Kidneys produce more urine


  Removes excess water from the body
• Dialysis


  1. Uses an artificial kidney

  2. Filters patient's blood

  3. Maintains same concentration of water and molecules as dialysis fluid

  4. Uses a partially permeable membrane to allow only certain molecules to diffuse across
• Dialysis fluid is constantly replaced to prevent equilibrium
• if water levels are too low?

  1. hypothalamus detect the change and send signals to pituitary gland
  2. pituitary gland release more ADH
  3. ADH travels in the bloodstream until the kidney
  4. Tubules will absorb more water and produce less urine
• Summary of low water levels.

  Less water, more ADH released then less urine
• If water levels are too high?

  1. Hypothalamus detect the change and send signals to pituitary gland
  2. pituitary gland will release less ADH
  3. ADH hormone will travel through the bloodstream to the kidney
  4. Tubules in the kidneys will absorb less water
  5. bladder will have more urine
• Summary of high water levels

  higher water levels, less ADH released more urine
• Filtration


  1. Liquid part of the blood is forced from the Glomerulus tangled blood vessel into the Bowman's Capsule

  2. Bowman's Capsule is the start of the tubule
• Glomerulus


  Tangled blood vessel
• Bowman's Capsule


  Start of the tubule
• Selective reabsorption


  Reabsorb only things they wanted back into the blood throughout the tubule
• Proximal convoluted tubule


  Where selective reabsorption occurs
• What are the risks of kidneys failure?

  toxins buildup, increasing waste products like urea

  poor regulation of ion levels
• If patient has kidney transplant, what type of drugs are they required?

  immunosuppressants
• What is kidney transplant?

  surgical procedure, where a person with unhealthy kidney receives a healthy kidney
• Rejection of a transplanted kidney

  the main risk is that the organ will be rejected, because the body’s immune system treats the transplanted organ as a foreign and tries to destroy it. Doctors reduce this risk by using medications (immunosuppressant) to suppress the immune system
• Stages of menstrual cycle

  • Lining builds up
  • Egg is released
  • No fertilization
  • Lining breaks down
  • Bleeding
• Oestrogen


  Stimulates the uterus lining to grow (stage 2), once it's grown oestrogen decreases
• Progesterone


  Maintains the lining of the uterus
• FSH


  Stimulates the egg to mature
• LH


  Stimulates the egg to be released in ovulation (stage 3)