Homeostasis & Response

• What does the hormone progesterone do?

  Maintains the uterus lining
• What is Intra-Cytoplasmic Sperm Injection (ICSI)?

  Sperm is injected into an egg cell with a tiny needle
• What is released across a synapse?

  Chemicals 
• How can oestrogen act as a contraceptive? 

  Inhibit FSH production, so that eggs can't mature
• What is the role of a motor neurone?

  To transfer a signal from the CNS to an effector
• What does Thyroid stimulating hormone (TSH) do?

  regulates thyroxine levels. 
• Which organ is TSH released from?

  Pituitary gland
• Describe what will happen when thyroxine levels are too high?

  If thyroxine levels are too high the thyroxine will inhibit the pituitary gland from producing TSH.

  TSH stimulates the thyroid gland to produce thyroxine, so less TSH means that the thyroid gland won't release as much thyroxine, and so over time thyroxine levels in the blood fall back to normal. This is an example of negative feedback.
• What is homeostasis? 

  Maintaining a stable internal environment despite changing conditions 
• What is contraception and what are some examples?

  A method or device used to prevent pregnancy

  • Condoms
  • Contraceptive pill
  • Contraceptive implants
  • Contraceptive patches
  • IUD's
• What does follicle stimulating hormone (FSH) do? 

  Stimulate an egg to mature 
• How is type 1 diabetes managed? 

  People with type 1 diabetes have to inject insulin after meals because they don't produce it themselves. They also have to monitor their diets (for example not have too much sugary food), and also exercise regularly. 
• What is the role of a sensory neurone?

  To transfer a signal from a receptor to the CNS
• How can progesterone act as a contraceptive? 

  Stimulate the production of mucus in the cervix, so sperm can't enter the uterus
• What are some internal conditions the body regulates?

  • Temperature
  • blood sugar levels
  • Blood pH balance
  • hydration.
• What are the four stages of the menstrual cycle?

  Menstruation - bleeding

  Follicular - uterus lining builds up

  ovulation - egg is released

  luteal- maintains uterus lining
• What is negative feedback?

  A negative feedback control system responds when conditions change from the ideal or set point and returns conditions to this set point. 
• What is the role of a receptor?

  To detect a stimulus
• Adrenaline causes changes in the body to prepare for a ‘fight or flight’ response.

  Describe 4 of these changes. 

  • Increase heart rate
  • Increase blood pressure
  • Increase blood flow to muscles 
  • Increases blood sugar (glucose) levels
• Name the two types of effectors and state what they do.

  Muscles- Contract

  Glands- Release Hormones
• Describe the pathway of a reflex arc?

  stimuli -> receptor cells -> sensory neurone -> CNS (spinal cord) -> relay neurone -> motor neurone -> effector -> response
• What happens across a synapse?

  electrical signals are converted to chemical signals to cross then are converted back to electrical signals
• What the four hormones in the menstrual cycle? and what do they do?

  Follicle-stimulating hormone (FSH)

  Luteinizing hormone (LH)

  Oestrogen

  Progesterone
• What does progesterone do and where is it produced?

  -Maintains the uterus lining

  -Produced in the ovaries
• What does Oestrogen do and where is it produced

  -Stimulate uterus lining to grow

  -Produced in the Ovaries
• What does Luteinising Hormone (LH) do and where is it produced?

  -Stimulate the release of the egg

  -Pituitary gland
• What does Follicle stimulating hormone(FSH) do and where it it produced ?

  -Stimulates one of the eggs to mature

  -Produced in the pituitary gland
• What is homeostasis? 

  Maintaining a stable internal environment despite changing conditions 
• Why does the body need to maintain optimal conditions?

  For optimal enzyme action and cell function
• What are examples of internal conditions?

  Blood glucose concentration 

  Blood pH

  Body temperature
• What is the role of a coordination centre? 

  Interprets changes and organises a response 
• The two types of effectors are muscles and glands. 

  Muscles contract when stimulated, whilst glands release hormones. 
• The nervous system is faster actin

  The endocrine system is longer lasting and acts more generally across the body
• Homeostasis relies on a system of negative feedback, meaning whenever the levels of something get too high they're brought back down, and whenever the levels of something get too low, they're brought back up. 
• How does negative feedback work?

  Any change in a system causes an action that reverses the change
• What passes along nerve cells?

  Electrical impulses
• What is the gap between two neurones called?

  Synapse
• What is released across a synapse?

  Chemicals 
• What is the role of a sensory neurone?

  To transfer a signal from a receptor to the CNS
• What are examples of reflexes?

  blinking

  Sneezing

  Moving hand if touched a hot surface