5.4 Hormonal Communication

Question 1

Define the endocrine system

Answer 1

A communication system using hormones as signalling molecules.

Question 2

Define a hormone

Answer 2

cell signaling molecules that are produced by endocrine glands and are secreted into the blood to be carried to a target cells/tissue.

Question 3

Define a target cell

Answer 3

cells that possess a specific receptor on their plasma membrane. Shape of receptor complimentary to hormone

Question 4

What are the two types of hormone?

Answer 4

Peptide
Steroid

Question 5

Name some examples of peptide hormones.

Answer 5

Adrenaline, insulin, glucagon

Question 6

Name some examples of steroid hormones.

Answer 6

Oestrogen and testosterone.

Question 7

How do hormones reach target cells?

Answer 7

They are secreted into capillaries that travel through glands.

Question 8

How do steroid hormones activate cells?

Answer 8

They dissolve through the cell surface membrane and bind to internal receptors

Question 9

How do peptide hormones activate cells?

Answer 9

They bind to external receptors on the plasma membrane

Question 10

Where is the adrenal gland found?

Answer 10

On top of the left kidney

Question 11

What is the outer layer of the adrenal gland?

Answer 11

The cortex

Question 12

What is the middle layer of the adrenal gland?

Answer 12

The medulla

Question 13

what type of hormones does the cortex secrete?

Answer 13

Steroid

Question 14

What type of hormone does the medulla secrete?

Answer 14

peptide

Question 15

What is the proper word for steroid hormones?

Answer 15

Corticosteroids

Question 16

Name the three steroid hormones

Answer 16

Mineralocortocoids
Glucocorticoids
Androgens

Question 17

Name the peptide hormone

Answer 17

Adrenaline

Question 18

Give an example and the function of a mineralocorticoid

Answer 18

Aldosterone
Increases absorption of Na+ in the kidneys
Cl- in the blood
Controls water retention and blood pressure

Question 19

Give an example and a function of a glucocorticoid

Answer 19

Cortisol
Increase of carbohydrate metabolism during stress

Question 20

Give an example and function of an androgen

Answer 20

The building blocks of oestrogen and testosterone
Promote reproductive development

Question 21

How are the receptor sites different for peptide and steroid hormones?

Answer 21

On the CSM vs. inside cell

Question 22

Why do different hormones need different receptor sites

Answer 22

Hormones have different shapes
Different complimentary receptor needed for each hormone
Target cells only possess receptor complimentary to hormone

Question 23

What is the role of acini in the pancreas

Answer 23

produce pancreatic enzymes that drain into the acinar lumen in the center

Question 24

What are the roles of the alpha and beta cells in the islets of Langerhans?

Answer 24

Alpha- glucagon
Beta-insulin

Question 25

Describe the exocrine tissues in the pancreas

Answer 25

-lobules containing many acini -acini made of cells surrounding lumen, digested enzymes secreted into duct -ducts collect together to form intralobular ducts -these combine to form the main pancreatic duct

Question 26

Describe the endocrine tissues in the pancreas

Answer 26

-Islets of Langerhans -apha cells secrete glucagon into the pancreatic blood vessels -beta cells secrete insulin into the pancreatic blood vessels

Question 27

Describe the process in which beta cells in the pancreas are stimulated to secrete insulin

Answer 27

1. K+ ions normally diffuse out of K+ ion channels 2.Increase in blood glucose conc. -> glucose diffuses into cell 3.Glucose metabolised into ATP 4.ATP closes K+ ion channels 5. Buildup of K+ conc. changes potential difference 6. Causes Ca2+ ion channels to open and Ca2+ ions to diffuse in 7. Ca2+ ions cause vesicles containing insulin to fuse to CSM.

Question 28

Define glycogenisis

Answer 28

The creation of glycogen in the liver by removing glocose from the blood

Question 29

Define gluconeogenisis

Answer 29

Formation of new glucose from other biological molecules such as lipids and amino acids

Question 30

Define glycogenolysis

Answer 30

The breakdown of glycogen supplies in the liver and muscle tissues

Question 31

Describe the process that occurs when the blood glucose concentration drops and is returned to homeostasis. What two processes occur during this?

Answer 31

- Decrease in blood glucose concentration detected by 𝛼-cells in the islets of langerhans - 𝛼-cells secrete glucagon -glucagon detected by receptors on liver cells -glycogen -> glucose - glucose -> blood Mainly glycogenolysis but also gluconeogenesis

Question 32

Describe the process that occurs when the blood glucose concentration increases and is returned to homeostasis. What process occurs during this?

Answer 32

- Increase in blood glucose concentration is detected by 𝛽-cells in the islets of langerhans - 𝛽-cells secrete insulin - receptors on liver and muscle cells detect insulin - liver and muscle cells remove glucose from blood and convert it into glycogen in a process called glycogenesis

Question 33

What kind of feedback system controls blood glucose concentration

Answer 33

negative feedback

Question 34

Describe negative feedback

Answer 34

A system which reverses a change applied to it through antagonistic effectors

Question 35

Describe the process that occurs when insulin binds to receptors on liver cells

Answer 35

1. Insulin binds to receptor 2. Activates Tyrosine Kinase enzyme 3. Phosphorylates (activates) inactive enzymes that cause... 4. Vesicles containing glucose transport proteins to fuse to CSM 5. More glucose diffuses in and is converted to glycogen 6. More glucose is converted to fats and used for respiration

Question 36

Describe the process that occurs when glucagon binds to receptors on liver cells

Answer 36

1. Glucagon binds to receptor on CSM 2. Activates G protein 3. Activates adenyl cyclase, causing the activation of cAMP 4. cAMP then activates inactive enzymes to... 5. Convert glycogen to glucose (glycogenolysis) 6. More fatty acids used in respiration 7. Amino acids and lipids converted to glucose (gluconeogenesis)

Question 37

Define Diabetes mellitus

Answer 37

A condition in which blood glucose concentration cannot be controlled effectively

Question 38

How does type 1 diabetes occur? What is the problem?

Answer 38

Autoimmune disease (could also occur as a result of a viral attack) The pancreas can no longer produce insulin and store glycogen

Question 39

How does type 2 diabetes occur? What's the problem?

Answer 39

obesity, lack of regular exercise, family history Can produce insulin but not enough. Probs because receptors become less receptive

Question 40

How do we treat type one diabetes?

Answer 40

- Insulin injections: blood glucose concentration can be monitored and insulin injected as required - Insulin pump: automatically injects required amount of insulin - Islet cell transplant: healthy 𝛽 cells are transplanted - Complete pancreas transplant - Stem cells from bone marrow or embryo

Question 41

What are the treatments for type 2 diabetes?

Answer 41

- Lifestyle changes - There are some medications that slow down the amount of glucose released into the blood from the liver

Question 42

Where do we get insulin from?

Answer 42

GMO bacteria

Question 43

What are the advantages of using insulin from bacteria?

Answer 43

- An exact copy of human insulin so faster acting and more effective - Less chance of developing tolerance to insulin - Lower risk of infection - Cheaper to manufacture vs. extracting from animals - Less likely to have moral obligations vs. from a pig