CB7 Respiration And Hormones

• homeostasis = Some of the conditions inside your body have to be kept the same (constant). If not, you can become ill or even die.
• Blood glucose regulation is due to two hormones. Insulin produced by pancreas lowers blood glucose levels. Glucagon also produced by the pancreas raises blood glucose levels
• When you eat = Your glucose level goes up after digestion of food, Insulin gets released from the pancreas into blood, Insulin makes the liver and muscles to turn excess glucose into glycogen, Glucose levels in blood decrease to normal
• when you don't eat = Your glucose level goes too low, Glucagon gets released from the pancreas into blood, Glucagon makes the liver turn glycogen into glucose, Glucose levels in blood increase to normal
• type 1 diabtetes = pancreatic cells do not produce insulin
• People with Type 1 diabetes have to inject insulin into the fat layer beneath their skin before eating.
• type 2 diabetes =

  1. Insulin –releasing cells not producing enough insulin
  2. Target organs not responding to the insulin properly.
• type 2 diabetes treatments = Treatment 1 : Eat healthily and keep the level of sugar in the diet low. Also keep physically active.

  Treatment 2 :Treatment 1 PLUS take medicines to reduce the amount of glucose that the liver releases into the blood

  Treatment 3 :Treatment 1 PLUS take medicines to make the target organs respond better to insulin
• As the number of people with Type 2 diabetes has increased, so has the average body mass. We say the two factors are CORRELATED.
• alveoli adaptations =

  1. Thin – so that particles do not need to diffuse very far
  2. Have a large surface area – so that there is more room for particles to diffuse.
• In humans, every cell has a blood vessel called a capillary alongside it so that materials can diffuse between the blood and cells.
• Surface area/Volume

  The bigger this value is the better a cell can get substances into it (If it’s LOW it’s SLOW)
• Gas exchange takes place at an alveolus.
• The alveoli make the lungs have a huge surface area : volume ratio as they greatly increase the total surface area.
• The oxygen and glucose diffuse into our cells and the mitochondria use them to make ENERGY to keep the cell alive. 

  Carbon dioxide and water are also made but they diffuse out of the cells and are removed from the body as wastes.

  This is process is called AEROBIC RESPIRATION.
• aerobic respiration is exothermic
• glucose + oxygen           =        carbon dioxide + water (aerobic)
• During exercise, your muscles need more energy. The rate of aerobic respiration increases and your muscle cells need to take in more oxygen and glucose from the blood.  
• to take in more oxygen and glucose =

  1. your heart beats faster to get more blood to these muscles

  2. You breathe faster to get more oxygen into the blood and to excrete more carbon dioxide.
• During very strenuous exercise, oxygen is used up faster than it is replaced. When this happens another type of respiration ALSO takes place called ANAEROBIC RESPIRATION. It takes place in the cytoplasm of cells.
• anaerobic respiration =

  1. Does not require oxygen
  2. Still needs glucose
  3. Produces lactic acid which makes your muscles ache
  4. Releases less energy from glucose than aerobic
• glucose         =           lactic acid (anaerobic)
• Heart and breathing rate remain high for a while after exercise because extra oxygen is needed to:

  1. replace the oxygen lost from blood
  2. break down the lactic acid
• endocrine glands  produce chemicals called HORMONES which also send messages around the body. They travel from one part of the body to the other in the blood. This makes it slower than the nervous system.
• thyroid = thyroxine
• pituitary gland = growth hormone
• adrenal glands = adrenalin
• ovaries = oestrogen and progesterone
• testes = testosterone
• pancreas = insulin/glucagon
• One hormone that affects metabolic rate is THYROXINE which is released in the thyroid gland. The thyroid gland is situated in the neck.
• Thyroxine can increase our metabolic rate by:

  1. Making the heart cells contract quicker and stronger
  2. Making protein and carbohydrate get digested quicker 
• metabollic rate = rate at which we use glucose to make energy
• high thyroxine negative feedback = High thyroxine levels inhibit release of TRH from hypothalamus, and then this inhibits the release of TSH from pituitary, this decreases the amount of thyroxine released into the blood by the thyroid gland
• low thyroxine negative feedback = Low thyroxine levels stimulates release of TRH from hypothalamus, and then this stimulates the release of TSH from pituitary, this increases the amount of thyroxine released into the blood by the thyroid gland
• Day 1- 5    Menstruation. Uterus lining breaks down and a unfertilised egg cell is lost during a ‘period’ of bleeding.
• Day 6-12 – an egg cell develops in an ovary.
• Day 13 - 15  Ovulation . An egg cell is released from an ovary and is moved by cilia along the oviduct. 
• Day 16 – 19 If the woman has sex during these days then fertilisation is likely leading to pregnancy.
• Day 5-28   Uterus lining thickens up again to receive a fertilised egg. If an egg is not fertilised then after day 28 the whole cycle starts again