5.1.4 hormonal communication Flashcards
What hormones are secreted by the Pituitary gland?
-Growth hormone: controls growth in bones and muscles.
-Anti-diuretic hormone: increases reabsorption of water in kidneys.
-Gonadotrophins: control development of ovaries and testes.
What hormones are secreted by the Thyroid gland?
-Thyroxine: controls rate of metabolism and rate that glucose is used up in respiration.
What hormones are secreted by the Adrenal gland?
-Adrenaline: increases heart rate and breathing rate and raises blood sugar level.
What hormones are secreted by the Testis?
-Testosterone: controls sperm production and secondary sexual characteristics.
What hormones are secreted by the Pineal gland?
-Melatonin: affects reproductive development and daily cycles.
What hormones are secreted by the Thymus?
-Thymosin: promotes production and maturation of white blood cells.
What hormones are secreted by the Pancreas?
-Glucagon: converts glycogen back to glucose in the liver.
-Insulin: converts excess glucose into glycogen in the liver.
What hormones are secreted by the Ovary?
-Oestrogen: controls ovulation and secondary sexual characteristics.
-Progesterone: prepared the uterus lining for receiving am embryo.
What is meant by endocrine?
Hormones released into bloodstream (plasma).
What is meant by exocrine?
Secretes hormone through ducts directly into target organs/surface of the body.
Where are the Adrenal glands located?
On the top of each kidney.
What are the Adrenal glands made up of?
-The Adrenal cortex
-The Adrenal medulla
What is the Adrenal cortex?
The outer region of the glands, produces hormones vital to life.
What is the Adrenal medulla?
The inner region of the glands, produces non-essential hormones.
What hormones does the Adrenal medulla secrete?
-Adrenaline:
increased heat rate, increased blood glucose concentration.
-Noradrenaline:
increased heart rate, widening of pupils, widening of air passages to the lungs, narrowing of the blood vessels.
What hormones are secreted by the Adrenal cortex?
-Glucocorticoids:
e.g. cortisol- regulates metabolism (breakdown of fats, lipids, and proteins). Affects blood pressure.
e.g. corticosterone- regulates inflammatory responses/immune responses.
-Mineralocorticoids:
e.g. aldosterone- regulate the salt and water balance/concentration in the blood, regulates blood pressure (guided by signals from the kidneys).
-Androgens:
Sex hormones (testosterone+oestrogen).
Why is the pancreas both an endocrine and an exocrine system?
Endocrine- secretes Insulin and Glucagon into the blood.
Exocrine- produces digestive enzymes (amylase, protease, lipase) into the digestive system.
What do the enzymes: Amylase, Protease, and Lipase, break up?
Amylase:
Starch into simple sugars.
Protease:
Proteins into amino acids.
Lipase:
Lipids into fatty acids and glycerol.
What are Islets of Langerhans and what do they produce?
Small regions of endocrine tissue within exocrine tissue.
Produces:
Alpha cells- Glucagon.
Beta cells- Insulin.
What are the main difference between endocrine and exocrine pancreatic tissue?
Endocrine- Lightly stained, large spherical clusters, produce and secrete hormones, Islets of Langerhans.
Exocrine- darker stained, small berry-like clusters, produce and secrete digestive enzymes, pancreatic acini.
What can increase blood glucose concentration?
-Diet
-Glycogenolysis
-Gluconeogenesis
What can decrease blood glucose concentration?
-Respiration
-Glycogenesis
What is meant by Gluconeogenesis?
Gluconeogenesis is the production of glucose from non-carbohydrates.
What is meant by Glycogenolysis?
Glycogenolysis is the breakdown of glycogen into glucose.
What is meant by Glycogenosis?
Glycogenosis is the building of glycogen.
What happens when blood glucose concentration is too high?
-Detected by beta cells in Islets of Langerhans.
-More Insulin released.
-Glycogenesis in liver/muscles.
-Increase uptake in cells.
-Increase rate of cellular respiration.
-Convert into fats (lipogenesis).
What happens when blood glucose concentration is too low?
-Detected by alpha cells in Islets of Langerhans
-Glucagon released.
-Glycogenolysis in liver/fat cells.
-Gluconeogenesis.
-Decrease uptake in cells.
-Decrease rate of cellular respiration.
How do beta-cells release insulin?
-Increase glucose inside cell.
-Increase ATP released by respiration.
-Increase ATP causes K+ channels on cell surface to close.
-Increase K+ in cell causes cell to be less positive (depolarisation).
-Depolarisation causes calcium ion channels to open.
-Increase calcium ions inside cells.
-Calcium ions move secretory vesicles containing insulin to cell surface.
-Vesicles->exocytosis->insulin release.
What is meant by Hyperglycaemia?
Too much glucose in the blood.
What is meant by Hypoglycaemia?
Too little glucose in the blood.
What is the difference between Type 1 and Type 2 diabetes?
Type 1 diabetes is when beta-cells in the Islet of Langerhans do not produce insulin. Whereas, type 2 diabetes is when beta-cells do not produce enough insulin or body cells do not respond properly to insulin (caused by poor lifestyle).
How can Type 1 diabetes be treated?
-Regular injections of insulin (insulin-dependent).
How can Type 2 diabetes be treated?
-Regulate diet and exercise.
-Drugs to stimulate insulin production in some cases.
What is medically produced insulin?
Insulin made from genetically modified bacteria-human gene for insulin inserted into bacterial cells.
What are the advantages of medically produced insulin?
-Less chance of an allergic reaction than pig/cow insulin.
-Make on a mass scale.
-Cheaper production costs.
-Less ethical/religious concerns.
What are the disadvantages of pancreas transplants?
-Long wait for a pancreas transplant because demand outweighs availability.
-Immunosuppressant drugs, which increase metabolic demand.
-80% effective.
How can stem cells be used to treat diabetes?
Totipotent stem cells have the ability to differentiate into any cell type (taken from embryos e.g. ‘spares’ from fertility treatment and terminations.
Could grow into Islet cells.
What are the advantages of stem cell therapy for diabetes?
-Donor availability would not be an issue.
-Reduced likelihood of rejection problems with embryonic stem cells generally not being rejected.
-People no longer have to use insulin injections.
