Homeostasis and Response

• Homeostasis


  The regulation of the internal conditions to maintain at optimum
• Internal conditions that need to be regulated

  • Body temperature
  • The water content of the body
  • The concentration of glucose in the blood
• Enzymes only work at a specific temperature
• Water is used to regulate temperature
• Water is needed for vital reactions
• Water affects osmosis
• Glucose is needed for respiration in all cells
• High blood glucose can cause damage
• Nervous system and Endocrine systems (hormones)


  Involved in homeostasis
• Hormones


  Chemical signals between cells
• Hormones


  • Wide affect + slow
  • Neuronal direct affect + fast
• Negative feedback


  Systems that work to maintain a normal/optimum state
• Negative feedback


  1. If a factor in the environment increases, one system changes to reduce this back to normal

  2. If a factor in one environment decreases, the system changes to increase this back to normal
• Glucagon (hormone) breaks glycogen (storage) into glucose (sugar)
• Insulin


  Produced, allows liver and body cells to use glucose, which reduces glucose level in blood
• Glucose used for respiration or stored as glycogen in muscles and liver
• Drink or food ingested (eaten)

  Increases glucose concentration in blood
• Glucagon produced


  Glucagon breaks down glycogen in muscles and liver to glucose, which raises blood glucose level
• Diabetes


  No ability to regulate blood glucose concentration properly
• Insulin


  A hormone produced by the pancreas
• Types of diabetes

  • Type 1 - Pancreas does not make insulin
  • Type 2 - The body stops responding to insulin, caused by genetic factors, high sugar diet and lack of exercise
• Pre-diabetics


  Need to exercise and have a low calorie diet to prevent insulin desensitisation
• Obesity is a risk factor for Type 2 diabetes
• People with Type 2 diabetes make enough insulin, but still cannot control their blood glucose concentration because the body cells are not sensitive to the insulin
• Treatments for Diabetes


  1. Diabetics are given insulin to inject to lower blood glucose at peaks (after meal times)

  2. Modern technology is able to monitor blood glucose to time insulin injections to keep glucose at a normal level
• Endocrine system


  The collection of glands that produce hormones to regulate: metabolism, growth and development, tissue function, sexual function, reproduction, sleep and survival
• Hormones

  Chemical messengers
• Endocrine glands


  Secrete hormones directly into the blood
• Hormones

  • Insulin controls blood glucose
  • Adrenaline prepares your body for fight, flight or freeze
• Pituitary Gland (Master Gland)


  One of its functions is the regulation of growth
• Pituitary gland regulation


  The hormone is secreted from pituitary -> The effector (gland or organ) -> Another hormone is secreted
• Pituitary gland


  Called the master gland as it regulates the secretion of hormones from other endocrine glands
• Nervous system


  • Acts very quickly, co-ordinates a response by the body, electrical impulse carries the message, chemical messenger diffuses across a synapse
• Hormone


  • Chemical messenger carried in the blood, long lasting response, chemicals made and released by glands, co-ordinate a response by the body
• Both men and women have oestrogen and testosterone, but men have much more testosterone and women have more oestrogen
• Oestrogen


  Promotes growth of uterine lining
• Testosterone


  Promotes sperm production
• Stimulate

  Increase / Encourage / Promote
• Inhibit


  Decrease/ Hinder
• Menstrual cycle


  The change in hormone levels in a woman during the 28-day cycle