Endocrine

Question 1

Pancreas - Islets of Langerhans Beta Cells

Answer 1

• Secretes insulin, reduces glucose levels in blood.
• Promotes glucose uptake into body cells.
• Causes glucose to glycogen and fat in skeletal muscles.
• Causes formation of glycogen from glucose.
• Causes glucose to be converted into fat in fat storage tissue.
• Regulated with negative feedback.

Question 2

Pancreas - Islets of Langerhans Alpha Cells

Answer 2

• Secretes glucagon, opposite of insulin.
• Increases blood glucose level by promoting glycogen to glucose breakdown in liver.
• Stimulates breakdown of fat in liver and fat storage tissues.

Question 3

Adrenal Cortex

Answer 3

• Aldosterone acts on kidneys, reduces sodium and increases potassium in urine.
• Cortisol promotes normal metabolism, withstand stress and repair damaged tissue.

Question 4

Adrenal Medulla

Answer 4

• Adrenaline prepares body for reaction to a threatening situation.
• Noradrenaline same as adreanline.

Question 5

Thymus

Answer 5

• Shrinks overtime.
• Secretes thymosins, influences T-lymphocyte maturation.

Question 6

Parathyroid Gland

Answer 6

Secrets parathyroid hormone, increases calcium levels in blood and phosphate excretion in urine.

Question 7

Thyroid Gland

Answer 7

• Secretes thyroxine (T4) and triiodothyronine (T3). T3 has 3 iodine, T4 has 4.
• Thyroxine: controls body metabolism by regulating reactions where complex molecules are broken down to release energy and maintain body temperature.
• Calcitonin is also released by C-cells for calcium and phosphate levels.
  
  • Secreted when calcium levels in blood increase.
  • Reduces calcium reabsorption by kidneys and bone breakdown.
  • If phosphate too high:
    
    • Moves phosphate into bone, reduced reabsorption by kidneys.

Question 8

Kidneys

Answer 8

Erythropoietin hormone, targets bone marrow, Stimulates production of red blood cells.

Question 9

intisitial cells of testes

Answer 9

Secretes testosterone, targets Muscles, skeleton, hair and genitals, Male: development of secondary sexual characteristics and sperm production.

Question 10

Ovary (corpus luteum)

Answer 10

Progesterone, Maintenance of uterine lining.

Question 11

Ovary (follicle cells)

Answer 11

Oestrogen, Development of secondary sexual characteristics and uterine lining thickening.

Question 12

Anterior lobe

Answer 12

• Makes and stores its own hormones and their release is controlled by specific releasing factors from hypothalamus.
• Growth hormone, thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotrophic hormone, luteinising hormone.
• Have their own releasing factor.
  Connected via bloodstream

Question 13

Posterior lobe:

Answer 13

• Hormones made in hypothalamus, stored in posterior lobe.
• Anti-diuretic hormone, oxytocin.
  Connected via nerve cells

Question 14

Hypothalamus functions

Answer 14

• Pituitary gland regulation:
  
  • Secretes releasing and inhibiting factors into blood vessels that go through infundibulum into the anterior lobe.
  • Stimulates/inhibits hormone secretion.
• Hormone glands:
  
  • Oxytocin and antidiuretic hormone is produced by special cell nerve bodies here.
  • Hormones go to posterior lobe via nerve cell extensions.
  • These hormones are stored in the lobe until required.

Question 15

Hormones alter cell activity by

Answer 15

• Activating certain genes in nucleus so that a particular enzyme or structural protein is produced.
• Changing the shape or structure of an enzyme so it is ‘off’ or ‘on’.
• Changing enzyme/structural protein production rate by changing transcription or translation rate during protein synthesis.

Question 16

Steroid Hormones

Answer 16

• Small, lipid soluble.
• Pass through plasma membrane to cytoplasm, bind to receptor molecules.
• Pass through nucleus, controls particular protein formation by acting on genes.
• Oestrogen, progesterone, testosterone, aldosterone, cortisol.

Question 17

Protein and Amine Hormones

Answer 17

• Water soluble, can’t pass through membrane.
• Bind to a specific receptor on the membrane.
• Causes a secondary messenger to activate particular enzymes in the cell.
• Hormones secreted by adrenal medulla, pituitary and pancreas.

Question 18

Enzyme Amplification

Answer 18

series of chemical reactions in which the product of one step in an enzyme that produces an even greater number of product molecules at the next step.

Question 19

Hormone clearance

Answer 19

hormones broken down in target cells, liver, or kidneys. Excreted in bile or urine.

Question 20

Hormones

Answer 20

Chemical messenger molecules produced and secreted from glands and organs in many body locations.
Are tissue-specific and circulate bloodstream until coming in contact with a complementary receptor.

Question 21

Endocrine glands

Answer 21

• Secrete hormones into extracellular fluid that surrounds cells that make up gland. Then passes directly into the blood stream, which delivers to specific target cells/tissues.
• No ducts.
• Pituitary, parathyroids, thyroid, adrenal, pancreas, ovaries, hypothalamus.

Question 22

Exocrine glands

Answer 22

• Secrete contents through tiny tubes or ducts into an interior/exterior body surface or body cavity.
• Sweat glands, lacrimal glands (tear glands).