hormonal communication

Question 1

endocrine system

Answer 1

• secretes hormones into blood plasma that travels to target cells which have receptors specific to a hormone

Question 2

peptide hormone

Answer 2

class of proteins which are bound by receptor proteins

Question 3

steroid hormone

Answer 3

-lipid based so can diffuses across the cell membrane

Question 4

action of adrenaline

Answer 4

-primary messenger
-binds to receptors on the surface membrane of target cell which activates the enzyme adenyl cyclase
- adenyl cyclases converts ATP to cyclic AMP (cAMP) which is the secondary messenger inside the cell
cAMP activates enzyme actions depending on the cell adrenaline binds too

Question 5

the structure and functons of the adrenal glands

Answer 5

-endocrine gland
-outer layer=cortex which releases steroid hormones e.g.cortisol and mineralcortisoids
-inner layer= adrenal medulla which releases peptide hormones e.g, adrenaline and noradrenaline

Question 6

Endocrine vs exocrine glands

Answer 6

Endocrine= secretes hormones into the bloodstream and are ductless
Exocrine= secretes chemicals into ducts

Question 7

Histology of the pancreas

Answer 7

• consists of the pancreatic acini which is a berry-like cluster
• has a exocrine function as hormones are secreted into the pancreatic duct
• has a darker stain
• islet of langerhan which has a endocrine function
• made up of Alpha and beta cells
  Alpha= glucagon
  Beta= insulin
• lighter stain
• large spherical structures

Question 8

How blood glucose levels is regulated

Answer 8

• if high = Beta cells in the islet of Langerhan release insulin. This targets livers and most body cells:
• increased conversion of glucose into fats
  -increased glycogenesis ( making glycogen from glucose)
  -increased respiration rate

If low
- liver and fat cells are targeted
- increases glucogenlysis ( break down of glycogen to glucose)

Question 9

how is insulin released

Answer 9

Low glucose
- potassium ion channels are open and calcium ions are closed
- resting potential of -70mv

High glucose
- glucose diffuses into the cell
-glucose is metabolised forming ATP
- ATP causes k+ channels to close
- membrane becomes depolarised
- Ca+ ion channels open
- Ca+ enter the cell causes insulin vesicles to fuse with the membrane to be released by exocytosis

Question 10

type one diabetes

Answer 10

-Beta cells cannot make insulin,
-thought to be a autoimmune response to beta cells
to treat can use insulin injections

Question 11

type two diabetes

Answer 11

• beta cells don’t produce enough insulin or cells not sensitive to insulin.
• can be caused by obesity and bad lifestyle
• can be treated by regular excersize, low carb diets

Question 12

the potental treatments for diabetes mellitus

Answer 12

• genetically modified insulin = purer than from extracting by pigs so less allergy risk
  -increases yield
  -less religious/ethical concern

-stem cells can be uses to to grow new islet of langerhan