5.4 Hormonal Communication

Question 1

What is a Hormone?

Answer 1

molecules(proteins or steroids) that act as messengers in the blood after being secreted from a gland

Question 2

Define ‘Secretion’

Answer 2

production and release of a USEFUL substance by a gland or cell; also, the substance produced

Question 3

What’s a target cell?

Answer 3

cells that possess a receptor, complementary to a peptide hormone, on their plasma membrane

Question 4

What is Endocrine communication?

Answer 4

Specialised glands secrete hormones into bloodstream.

Circulatory system carries hormone to target cell/ tissue.

Question 5

What is the Endocrine system?

Answer 5

a communication system that uses hormones as signalling molecules

Question 6

Where are the Adrenal Glands located?

Answer 6

Above the kidneys

Question 7

Describe ‘First & second messenger’

Answer 7

• Fist messenger: non-steroid hormone that bind to their receptor and initiate an effect inside the cell
• Second messenger: stimulates a change in the activity of the cell

Question 8

What is the structure of the Adrenal Glands?

Answer 8

triangle-ish
outer part=cortex
inner part =medulla

Question 9

What are the three layers (Zones) of the Adrenal Cortex?

Answer 9

• Zona glomerulosa- outer
• Zona fasciculata - middle
• Zona retucularis - inner

Question 10

What hormone does the Adrenal Medulla secrete?

Answer 10

Adrenaline & Noradrenaline in response to danger, stress or excitement as part of the fight or flight response.

Question 11

Which hormones does the Cortex secrete?

Answer 11

• Outer layter, Mineralocorticoids e.g. aldosterone: controls concentration of Na+ & K+ ions in blood.(outer layer)
• Midddle layer, Glucocorticoids: stimulates an increase in blood glucose concentration.(middle layer)

Question 12

What are some effects of Adrenaline?

Answer 12

• Increase heart rate
• Increase stroke volume
• Dilate pupils
• Stimulate conversion of glycogen to glucose

Question 13

What’s the Pancreas?

Answer 13

small organ below stomach with endo and exo-crine functions

Question 14

What are the two main Pancreatic functions?

Answer 14

• secrete hormones from islets of Langerhans(endocrine)

* secrete pancreatic juices into small intestines(exocrine)

Question 15

What’s the difference between Exocrine and Endocrine glands?

Answer 15

• Exocrine secrete substances into ducts

* Endocrine secret substances directly into the bloodstream

Question 16

Why is it important that blood glucose concentration remains stable?

Answer 16

• Maintain constant blood water potential: prevent osmotic lysis/ crenation of cells.
• Maintain constant concentration of respiratory substrate: organism maintains constant level of activity regardless of environmental conditions.

Question 17

What are the two types of Hormones?

Answer 17

• Lipid-soluble (steroid) hormones, diffuse into cell & bind to complementary receptor in cytoplasm.
• Peptide hormones, bind to complementary receptor on cell-surface membrane

Question 18

Define Glycogenesis

Answer 18

glucose converted to glycogen

Question 19

Define Glycogenolysis

Answer 19

hydrolysis of glycogen to glucose

Question 20

Define Gluconeogenesis

Answer 20

glucose FROM amino acids & glycerol

Question 21

What is the role of Glycogen?

Answer 21

maintains blood glucose concentration by acting as a storage version of glucose

Question 22

What is Glucagon?

Answer 22

the hormone that helps control blood glucose levels by stimulating the liver to convert glycogen to glucose

Question 23

What is Insulin?

Answer 23

a hormone that helps control blood glucose levels by stimulating conversion of glucose to glycogen

Question 24

What are Alpha cells?

Answer 24

make up endocrine tissue in the pancreas, secrete Glucagon

Question 25

What are Beta cells?

Answer 25

make up endocrine tissue in the pancreas, secrete insulin

Question 26

What Homeostatic mechanism controls blood glucose level?

Answer 26

Negative feedback

Question 27

What's the mechanism for Insulins release?

Answer 27

1. Beta cells contain Ca & k ions channels with k+ channels open so k+, -70mv 2. when glucose conc high glucose rushes in 3. glucose makes ATP, causes K+ channels to close 4. K+ no longer leaves cell, charge increases 5. potential difference change makes Ca+ channels to open 6. Ca enters cell and causes insulin secretion

Question 28

Outline the role of Insulin when blood glucose concentration increases

Answer 28

1. β cells in Islets of Langerhans in pancreas detect decrease & secrete Insulin into bloodstream. 2. Insulin binds to surface receptors on liver & muscle cells activating glycogenesis. 3. Glucose eters cells, stuff happens 4. β cells detect that blood glucose concentration has returned to optimum & stop producing Insulin (negative feedback).

Question 29

Outline the role of Glucagon when blood glucose concentration decreases

Answer 29

1. 𝞪 cells in Islets of Langerhans in pancreas detect decrease & secrete glucagon into bloodstream. 2. Glucagon binds to surface receptors on liver cells activating glycogenolysis & gluconeogenesis. 3. Glucose diffuses from liver into bloodstream. 4. 𝛼 cells detect that blood glucose concentration has returned to optimum & stop producing glucagon. (negative feedback)

Question 30

Use the secondary messenger model to explain how Glucagon works

Answer 30

1. Hormone-receptor complex forms. 2. Conformational change to receptor activates G-protein. 3. Activates adenyl cyclase, which converts ATP to cyclic AMP (cAMP). 4. cAMP activates protein kinase A pathway. 5. Results in glycogenolysis.

Question 31

What are some of the effects of Insulin?

Answer 31

* Glucose in cells converted to glycogen * More glucose enters cells (increases cell permeability to glucose) * More glucose used in respiration * Inhibits glycogenolysis

Question 32

Define & Explain the causes of Type 1 Diabetes mellitus

Answer 32

Body cannot produce insulin due to autoimmune response which attacks 𝛽 cells of Islets of Langerhans

Question 33

How can type 1 Diabetes be controlled?

Answer 33

• Injecting insulin • Islet transplant • Pancreas transplant *maybe stem cells in future

Question 34

Define Type 2 Diabetes mellitus

Answer 34

Body doesn't produce enough insulin various causes including

Question 35

What are some risk factors for type 2 Diabetes mellitus?

Answer 35

* Poor diet (sugar rich) * Lack or exercise/ sedentary lifestyle * Obesity * Ethnic origin (Black& Asian)

Question 36

How can type 2 Diabetes be controlled?

Answer 36

can be treated by lifestyle changes like • Regular exercise • Carefully monitor diet • insulin injections

Question 37

What is the main source of Insulin, why is it different from say years ago?

Answer 37

used to be pigs but now genetically modified bacteria

Question 38

What are the advantages to using Bacteria Insulin?

Answer 38

* cheaper and more efficient to produce * Exact copy of human insulin so fast & effective * Less chance of immune rejection * less likely to raise ethical concerns

Question 39

what are Acini

Answer 39

groups of acinus cells that group together to form tubules that form the pancreatic duct

Question 40

what is the role of ducts

Answer 40

how Fluids are transported in the EXOcrine system, they move through theses instead of the blood

Question 41

what is hypoglyceamia

Answer 41

Low levels of blood glucose, cells

Question 42

what is hyperglyceamia, what would

Answer 42

High levels of blood glucose, cells lose water