Hormonal communication

• What are hormones?


  Chemical messengers which travel in the blood to activate target cells
• What are endocrine glands?

  Ones which secrete hormones into the blood to reach the target organ
• What are 8 examples of endocrine glands?

  1. Endocrine pancreas

  2. Testes

  3. Ovaries

  4. Pituitary gland

  5. Thyroid gland

  6. Pineal gland

  7. Adrenal gland

  8. Thymus
• What are gonads?


  Reproductive organs
• What are 3 examples of hormones made by the pituitary gland?

  1. Growth hormone

  2. ADH

  3. Gonadotropins
• What does growth hormone do?

  Stimulates bone and muscle growth
• What does ADH do?

  Increases water reabsorption in the kidneys
• What do gonadotropins do?

  Control development of the sex organs
• What does the pineal gland produce?

  Melatonin
• What does melatonin do?

  Controls sleep/wake cycles and affects reproductive development
• What does the Thyroid gland produce?

  Thyroxine
• What does thyroxine do?

  Controls rate of metabolism and rate at which glucose is used up in respiration, as well as promoting growth
• What does the thymus produce?

  Thymosin
• What does thymosin do?

  Promotes the proliferation and maturation of T cells
• What 2 hormones are produced by the endocrine pancreas?

  Glucagon and insulin
• What hormone do the testes produce?

  Testosterone
• What does testosterone do?

  Influences sperm cell development and also produces the male secondary sex characteristics
• What 2 hormones do the ovaries produce?

  1. Estrogen

  2. Progesterone
• What does estrogen do?

  Creates secondary sex characteristics in the female and controls ovulation
• What does progesterone do?

  Maintains lining of uterus
• What are the 2 types of hormone?

  Steroid and non-steroid
• What are target cells?

  Cells that have receptors for a particular hormone
• What is an example of a steroid hormone?

  Estrogen
• What is an example of a non-steroid hormone?


  Adrenaline
• What differentiates how steroid and non-steroid hormones behave?

  Steroid hormones are lipid-soluble and pass through the plasma membrane of the target cells, but non-steroid hormones are not lipid-soluble and so must bind to receptors on their cell surface membrane
• What happens when a steroid hormone passes into a target cell?

  It binds to a receptor to form a hormone-receptor complex, which then acts as a transcription factor for a specific gene
• What 2 places in the cell can steroid hormone receptors be found?

  Nucleus and cytoplasm
• How do non-steroid hormones work?

  They bind to a cell-surface receptor which causes a cascade reaction within the cell mediated by secondary messengers
• Which of neuronal and hormonal communication is quicker?

  Neuronal
• Which of neuronal and hormonal communication is longer-lasting?

  Hormonal
• What is the difference between hormonal and neuronal communication in terms of how widespread the response is?

  Neuronal tends to be localised, hormonal is much more widespread (although limited to target organs)
• What is the difference between hormonal and neuronal communication in terms of whether the response is temporary or permanent?

  Neuronal tends to be temporary, hormonal can be temporary but can also be permanent
• What is the difference between hormonal and neuronal communication in terms of the reversibility of the response?

  Neuronal tends to be reversible, hormonal can have irreversible effects
• What are the 3 parts of the adrenal gland?

  Capsule, cortex, medulla
• Where in the body are the adrenal glands found?

  On top of the kidneys
• What is the functional of the adrenal glands' capsule?

  It is a protective membrane layer
• What 3 types of hormone are produced by the adrenal medulla?

  1. Glucocortisoids

  2. Mineralocortisoids

  3. Androgens
• What androgens are produced by the adrenal medulla?

  Small amounts of the opposite sex hormone
• What regulates the release of glucocortisoids?


  The hypothalamus
• What 3 things do glucocortisoids regulate?

  1. Metabolism

  2. Blood pressure

  3. Immune response