5.1.4 HORMONAL CONTROL BIOLOGY OCR A LEVEL

?
  • Created by: Davina1st
  • Created on: 22-04-22 19:46
What is a hormone?
Chemical messengers which travel around the body in the blood stream
1 of 29
What is an endocrine gland?
A group of cells which are specialised to secrete chemicals - known as hormones, directly into the bloodstream. e.g. the pancreas and adrenal gland.
2 of 29
What is an exocrine gland?
E.g. those in the digetsic system, secrete chemicals through ducts into organs or to the surface of the body
3 of 29
What are target cells?
Where the hormones diffuse to in the blood and bind to specific receptors for that hormone, found on membranes or cytoplasm.
4 of 29
What are steroid hormones/lipid soluble?
Pass through lipid component of cell membrane and bind to steroid hormone receptors to form hormone-receptor complex. Receptor present in cytoplasm or nucleus. Hormone-receptor complex acts as transcription factor which facilitates/inhibits hormone.
5 of 29
What are non-steroid hormones?
Hydrophilic so cannot pass through cell membrane, instead bind to speicifc receptors on cell surface membrane of target cell triggers cascade reaction by second messengers. e.g. adrenaline.
6 of 29
Is neuronal or hormonal communication faster? Which lasts longer?
Hormones are not directly released to target cells so neuronal communication is faster. Hormones are not broken down as quickly as neurotransmitters so the effect lasts longer and has a more widespread effect.
7 of 29
Describe the adrenal glands
Approx 3cm height and 5cm length, located on top of each kidney. Cortex - outer region - hormones that are vital e.g. cortisol and adrenal medulla - inner region produces none essential hormonals e.g. adrenaline.
8 of 29
What are the three main types of hormone produced in adrenal cortex?
Glucocorticoids, mineralocorticoids, androgens
9 of 29
What are the hormones secreted by the adrenal medulla?
Adrenaline and noradrenaline
10 of 29
How does the pancreas act as an exocrine gland and an endocrine gland?
Exo- produce enzymes and releases them via duct into duodenum. Endo- produce homrones and releases them into blood.
11 of 29
Describe the role of the pancreas as an exocrine gland?
Makes digestive enzymes which are secreted into ducts eventually leading to pancreatic duct into duodenum. Produces amylases, proteases and lipases.
12 of 29
Describe the role of the pancreas as an endocrine gland?
Islets of Langerhans are responsible for producing insulin and glucagon which are secreted directly into the bloodstream.
13 of 29
What type of cells produce insulin/glucagon? Where are they located?
alpha - glucagon beta- insulin from islets of Langerhans. Alpha cells are more larger and numerous within an islet
14 of 29
What is glycogenolysis? Is it a response to increase blood glucose or lower blood glucose concentration?
Increase blood glucose conc- glycogen stored in liver and muscle is broken down and released into bloodstream increasing blood glucose concentration.
15 of 29
What is gluconeogenesis? Is it a response to increase blood glucose or lower blood glucose concentration?
Increase blood glucose conc- production of glucose from non-carbohydrate sources e.g. from lipids and amino acids. Glucose released into bloodstream increases blood glucose concentration.
16 of 29
What is glycogenesis? Is it a response to increase blood glucose or lower blood glucose concentration?
Lower - production of glycogen. Excess glucose taken in through diet is converted into glycogen which is stored in liver.
17 of 29
Is repiration a response to increase blood glucose conc or lower blood glucose conc?
To decrease blood glucose conc. Glucose in excess used up to release energy.
18 of 29
How does insulin work?
Beta cells detect increase in blood glucose conc and secrete insulin directly into bloodstream. binds to glycoprotein receptor on target cell causing change in shape to glucose transport protein channels. allowing more glucose to enter the cell.
19 of 29
How is insulin broken down?
By enzymes in cells of the liver, to maintain its effect has to constantly be secreted. Insulin secretion can begin minutes after food enters the body.
20 of 29
How does negative feedback work? Is the control of blood glucose concentration positive or negative feedback?
Ensures that in any control system changes are reversed and returned back to the set level. Negative.
21 of 29
What is the role of glucagon?
Only liver and fact cells have receptors to glucagon so they can only respond. Glycogenolysis, reduce amount of glucose absorbed by liver cells, gluconeogenesis,
22 of 29
Describe the mechanism by which the beta cells of the islet of Langerhans control insulin secretion?
K+ channels in plasma membrane of beta cell are open and K+leave the cell. =-70mv potential with respect to outside of the cell. Glucose enters cell when blood glucose rises = ATP, bind to K+ cause them to close -30mv. Depolarisation Ca2+ enter.
23 of 29
What is the difference between type 1 and type 2 diabetes?
Type 1 - unable to produce insulin, no prevention/cure, normally begins in childhood. 2 - cannot effectively use insulin to control blood sugar. Related to diet. Symptoms less severe and develop slowly. Mostly seen in children.
24 of 29
How is type 1 diabetes treated?
Regular injections of insulin, drop of blood analysed tells how much insulin to be injected. Increases amount of glucose absorbed by cells and causes glycogenesis to occur resulting in reduction of blood sugar.
25 of 29
How is type 2 treated?
First line of treatment to regulate carbohydrate intake through diet/increase exercise. Drugs to stimulate insulin production can also be used.
26 of 29
How has medically produced insulin changed over time?
Originally obtained from cows and pigs, in 1955 structure of human insulin detected and made by genetically modified bacteria. now can potentially use stem cells to diffrentiate into b cells and transplanted.
27 of 29
What are some of the advantages/disadvantages of the medically produced insulin?
From cows and pigs - difficult and expensive, ethical and religious concerns. Genetically modified - cheaper, more religious and ethical. Stem cells - more people able to treated but could lead to tumours as it needs to be studied more.
28 of 29
What are three advantages of stem cell as a treatment f diabetes?
No issue with donor availability, stem cells produce unlimited source of B cells, reduced likelihood of of rejection problems as embryonic stem cells are generally not rejected by the body. People no longer have to inject themselves with insulin.
29 of 29

Other cards in this set

Card 2

Front

What is an endocrine gland?

Back

A group of cells which are specialised to secrete chemicals - known as hormones, directly into the bloodstream. e.g. the pancreas and adrenal gland.

Card 3

Front

What is an exocrine gland?

Back

Preview of the front of card 3

Card 4

Front

What are target cells?

Back

Preview of the front of card 4

Card 5

Front

What are steroid hormones/lipid soluble?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Cellular processes resources »