5.1.4 Hormonal communication

Question 1

What is the endocrine glands?

Answer 1

hormones are released by the endocrine gland into the blood
they are ductless

Question 2

What are exocrine glands?

Answer 2

they produce hormone that is not directly released in the blood
they have a duct that carries the secretion to another place

Question 3

What are the 2 types of hormones?

Answer 3

peptide hormones - cannot enter cell

lipid based hormones - can diffuse through phospholipid layer

Question 4

What is the action of adrenaline?

Answer 4

• hormone adrenaline is the 1st messenger
• hormone has specific and complementary shape to its target cell
• adrenaline binds to receptor causes adenyl cyclase in the cell to activate
  -converts ATP into cAMP which acts as a 2nd messenger
  -cAMP activates different enzymes/cascade of reactions

Question 5

Draw the structure of adrenal gland?

Answer 5

• found onto of kidney
• outer layer is the adrenal cortex (produces essential hormones)
• middle layer is the adrenal medulla (produces non-essential hormones)

Question 6

What are the hormones produced by the adrenal cortex?

Answer 6

cortisol;
aldosterone;
sex hormones;
(oestrogen and testosterone)

Question 7

What is the function of cortisol?

Answer 7

• stimulates glycogenolysis;
• reduces inflammations;
  -regulates blood pressure;

Question 8

What is the function of aldosterone?

Answer 8

sodium and potassium ions in the reabsorption in the kidneys;
water reabsorptions;
control of blood pressure;

Question 9

What is the function of sex hormones?

Answer 9

aid in the development of the gametes

Question 10

What are the hormones produced by the medulla?

Answer 10

adrenaline;
noradrenaline;

Question 11

What is the function of adrenaline?

Answer 11

increases heart rate;
stimulates glycogenolysis;
triggers flight/fight response;

Question 12

What is the function of noradrenaline?

Answer 12

increases heart rate;
stimulates glycogenolysis;
triggers flight/fight response;

Question 13

Is the pancreas an endocrine or an exocrine gland?

Answer 13

exocrine = enzymes are carried to the gall bladder in the pancreatic duct

endocrine = insulin and glucagon are released directly into the blood stream

Question 14

Where in the pancreas are the hormones secreted?

Answer 14

Islets of Langerhands

Question 15

What are the 2 types of cells in the Islets of Langerhans and what hormones do they secrete?

Answer 15

alpha cells = glucagon
beta cells = insulin

Question 16

Draw a image of what you would see of a pancreatic cell using a microscope?

Answer 16

Acini
Islet of Langerhans
Pancreatic duct
Blood vessels

Question 17

What is the normal range of blood glucose metabolism?

Answer 17

4-6 mmol dm-3

Question 18

When does blood glucose concentration increase?

Answer 18

eating a carb rich diet
glycogenolysis
gluconeogenesis

Question 19

When does blood glucose concentration decrease?

Answer 19

respiration
glycogenesis

Question 20

What occurs when blood glucose is too high?

Answer 20

• detected by beta cells in the islets of langerhans in the pancreas
• the hormone insulin is secreted into the blood
• target cells are hepatocytes in the liver
• insulin binds to the specific and complementary receptors on the cell membranes of the hepatocytes
• insulin acts as first messenger and this causes adenyl cyclase to be activates
• adenyl cyclase activates cAMP
• more glucose enters the cells + glygogenesis
• more glucose is used in respirations
  = causes blood conc to fall

Question 21

What is lowering blood glucose an example of?

Answer 21

Negative feedback

Question 22

What happens if blood glucose levels are too low?

Answer 22

• low glucose blood levels are detected by the alpha cells in the islets of Langerhans in the pancreas
• glucagon is secreted into the blood by the pancreas
• target cells are hepatocytes in the liver
• glycogen is converted into glucose (glycogenolysis)
• more fatty acids are used in respiration
• amino acids and fats are converted to glucose (gluconeogensis)
  = increases blood glucose levels

Question 23

How is insulin secretion controlled by the beta cells?

Answer 23

• plasma membranes of beta cells contain potassium and calcium ion channels
• potassium ions channels are normally open and sodium channels are closed = making the cell more negative
• when blood glucose levels are high, glucose molecules diffuse into the cell;
• the glucose molecules are used in respiration to produce ATP
• the extra ATP caused potassium ion channels to close
• potassium ions can no longer diffuse out and the potential difference across the membrane becomes less negative
• calcium ion channels open
• calcium ions enter the cell and cause vesicles containing insulin to fuse with the plasma membrane and release insulin via exocytosis

Question 24

What is diabetes?

Answer 24

when the body is no longer able to control glucose levels in the blood

can lead to hyperglycemia = high blood glucose levels

can lead to hypoglyceamia = low blood glucose levels

Question 25

What is type 1 diabetes?

Answer 25

• usually starts in childhood
• the body no longer produces any insulin;
  beta cells not functioning properly;
  -body cannot store excess glucose and glycogen
• thought to be an autoimmune disease;
• body destroys its own beta cells
• genetic;
• thought to be triggered by a virus/environmental factor

Question 26

What is type 2 diabetes?

Answer 26

• usually starts later in life due to obesity
• body doesn’t respond to inulin/not enough insulin is produced
• thought to be because the receptor for insulin doesnt work properly;

Question 27

What factors bring early onset for type 2 diabetes?

Answer 27

obesity;
physical inactivity;
high blood pressure;
being asian/afro-caribbean;
family history;
males;
excessive alcohol intake;

Question 28

What is treatment for type 1 diabetes?

Answer 28

insulin injections

Question 29

What is the treatment for type 2 diabetes?

Answer 29

maintain a low carb diet with low glucose
exercise regulary

Question 30

How can insulin be produced?

Answer 30

gentically modified bacterial plasmids

stem cells