Topic 7 - Animal coordination, control and homeostasis

• What are hormones?

  Chemical messengers produced by glands in the endocrine system that regulate various bodily functions. They travel to their target organs.
• What is the endocrine gland?

  A gland that secretes hormones directly into the bloodstream.
• What is the function of the pituitary gland?

  The pituitary gland is responsible for producing and releasing hormones that regulate various bodily functions, including growth, reproduction, and metabolism.
• What is the function of the Thyroid gland?

  The production of the thyroxine hormone - responsible for rate of metabolism, heart rate and temperature.
• What is the function of the ovaries?

  To produce eggs and oestrogen which is involved in the menstrual cycle.
• What is the function of the testes?

  Sperm production and testosterone secretion.
• What is the function of the adrenal glands?

  To produce adrenaline - which triggers the fight or flight response and cortisol - which raises the heart rate and causes stress.
• What is the function of the pancreas?

  The production of insulin and glucagon to maintain glucose levels.
• What does adrenaline do to the body?

  Increases heart rate and blood pressure, increases blood flow to the muscles, raises blood-sugar levels by stimulating the pancreas to secrete more glucagon to produce more glucose.
• How does thyroxine control metabolism in a negative feedback system?

  1. The Hypothalamus detects low levels of thyroxine|
  2. This causes the production of TSH from the pituitary gland.
  3. TSH causes the production of thyroxine from the thyroid gland
  4. When thyroxine levels are high, the hypothalamus detects that and stops the pitapituitaryatary gland from secreting TSH.
• What is the function of the pituitary gland?

  The pituitary gland is responsible for producing TSH and FSH. (The production of stimulating hormones).
• What are the stages of the menstrual cycle?

  Stage 1 (day 1): the uterus lining begins to break down.

  stage 2 (day 4 - 14): The uterus lining is repaired.

  stage 3 (day 14): Ovulation occurs and the egg is released.

  stage 4 (day 14 - 28): The uterus lining is maintained.
• What is a good way of remembering the menstrual cycle?

  MR. OM FOLP.
• What are the Hormones used during the menstrual cycle?

  FSH: Released by the pituitary gland - causes egg follicles to mature and stimulates the production of oestrogen.

  Oestrogen: released by the ovaries - causes the uterus lining to grow and causes a high stimulation of LH.

  LH: Released by the pituitary gland - causes the egg follicles to release the egg and turns the remaining follicle into the corpus luteum.

  progesterone: released by the corpus luteum - maintains the lining of the uterus and stops the release of LH and FSH.
• If the egg does not get fertilised, the progesterone levels will drop after 14 days and the menstrual cycle is repeated. If the egg is fertillised, progesterone levels will remain high to maintain the uterus lining.
• What type of hormones are used to prevent pregnancy?

  progesterone and oestrogen. Osetrogen prevents the production of FSH and progesterone stimulates cervical mucus - making it harder for the sperm to reach an egg.
• What are the pros and cons of hormonal barriers?

  Pros: Effective in preventing pregnancy, easy to use, no side effects for most people. Cons: Does not protect against sexually transmitted infections, may cause side effects such as irregular bleeding or hormonal imbalances.
• What are the pros and cons of physical contraceptive barriers?

  Pros: Effective in preventing pregnancy, easy to use, no hormonal side effects, can be used by both males and females. Cons: Expensive, uncomfortable, and may not be reliable.
• How does clomifene increase fertility?

  By stimulating the production of LH and FSH which increases the chance of producing an egg.
• What is the process of IVF?

  In vitro fertilization (IVF) is a process where eggs are retrieved from a woman's ovaries, fertilized with sperm in a laboratory, and then transferred back into the woman's uterus.
• Conditions in the human body must be kept steady and constant for the body to function properly.
• What is the effect of thermoregulation on enzyme activity?

  keeps enzymes working at optimal levels.
• What is the effect of osmoregulation on animal cells?

  Water levels and mineral salts in the blood are controlled to protect animal cells by stopping too much water from entering or leaving them.
• The hypothalamus maintains an optimum temperature of 37C to keep all enzymes working at optimal levels. Homeostasis is used to counteract the changes.
• what happens when you are too hot?

  Erector muscles relax so hairs lie flat.

  Lots of sweat is produced by the sweat gland in the dermis and is released to the epidermis. The water takes in heat when it is evaporated.

  Blood vessels close to the surface of the skin begin to dilate (vasodilation) - allowing heat to be released more easily and help evaporate the sweat.
• what happens when you are too cold?

  Erector muscles contract - hairs stand up which create an insulating layer.

  Sweat is no longer produced.

  blood vessels near the skin begin to constrict (vasoconstriction) which allows less heat to be released into the surroundings.

  Muscles begin to shiver which increases the rate of respiration.
• How is blood glucose controlled?

  When the Hypothalamus detects low blood sugar levels, it allows the pancreas to produce glucagon. Glucagon breaks down the stored glycogen in the liver and turns it into glucose which will be in the bloodstream. When the Hypothalamus detects high blood sugar levels, it allows the pancreas to produce insulin. Insulin turns glucose in the bloodstream into glycogen, which is then stored in the liver.
• What is the cause of type 1 diabetes and how is it controlled?

  Cause: The pancreas produces little to no insulin.

  Control: Insulin replacement therapy and blood sugar monitoring.
• What is the cause of type 2 diabetes and how is it controlled?

  Cause: When a person becomes resistant to insulin and does not respond to it correctly.

  Control: Eating a healthy diet, exercising and take medical injections.
• What is the formula for BMI?

  BMI = weight (kg) / height^2 (m^2)
• What is the structure of the urinary system?

  Kidneys, ureters, bladder, and Urethra.
• What happens in the nephron during ultrafiltration?


  The liquids in the blood like urea, ions, and glucose enter the glomerulus and then get forced into the bowman's capsule while bigger molecules stay.

  As the liquids flow along the nephron, useful substances like glucose get selectively absorbed AGAINST THE CONCENTRATION GRADIENT.

  Whatever is not absorbed goes to the collecting duct then the ureter to be passed down as urine.

  
• urea is produced from the breakdown of excess amino acids in the liver.
• Explain the effect of ADH on the permeability of the collecting duct in regulating the water content of the blood:

  The Hypothalamus detects low levels of water concentration. This allows the pituitary gland to secrete ADH which will make the kidney absorb more water. When the Hypothalamus detects high levels of water concentration, it allows the pituitary gland to release ADH - making the kidney absorb more water.
• People who have kidney failure use a kidney dialysis machine to filter the blood and remove waste products regularly to keep their blood clean. The dialysis fluid contains the same amount of glucose and salts in the blood - no change. The barrier is permeable to ions and waste substances allowing the blood to be filtered well.
• Kidney transplants are done with patients who have kidney failure. They get a donor that has a kidney that is compatible with the recipient. The patient takes drugs that suppress the immune system so that it does not attack the transplanted kidney.