Hormonal communication

Question 1

What system do hormones belong to?

Answer 1

the endocrine system

Question 2

What is the system made up of?

Answer 2

endocrine gland

an endocrine gland is a group of cells whivh are specialised to secrete chemical - hormones

Question 3

How are hormones transported through the body?

Answer 3

through the blood stream in the blood plasma

hormones diffuse out of the blood and bind to specific receptors for that hormone, found on the membrane, or in the cytoplasm of cells in the target organs

these are known as target cells

Question 4

What are the characteristics of steroid hormones

Answer 4

• lipid-soluble
• pass through the lipid component of the cell mebrane and bind to steroid hormone receptors to form a hormone-receptor complex
• they may be in the cytoplasm or the nucleus depending on the hormone
• the hormone-receptor complex formed acts as a transcription factor which in turn facilitates or inhibits the transcription of a specific gene
• oestrogen is an example of a hormone which works in this way

Question 5

What is the characteristics of non-steroid hormes?

Answer 5

• hydrophillic so cannot pass directly through the cell membrane
• instead they bind to specific receptors on the cell surface membrane of the target cell
• this triggers a cascade reaction mediated by chemicals called second messenger
• adreanalines is an example of a hormone which works in this way

Question 6

How does hormonal communication compare to neuronal?

Answer 6

1. hormones are not released directly onto their target cells, slower and less specific form of communication - slower transmission and response
2. not broken down as quickly as neurotransmitters, it can result in a much longer lasting and more widespread effect - e.g. insulin and glucagon are responsible for controlling blood glucose conc. - a number of organs are involved in this process
3. effect may be permanent and irreversible