The endocrine system

Question 1

Describe the endocrine system

Answer 1

• Sends info as chemical signals
• Involves glands and hormones
• Hormones are secreted when a gland is stimulated

Question 2

Gland

Answer 2

-A group of specialised cells that secrete a useful substance e.g. a hormone

Question 3

How can glands be stimulated?

Answer 3

• By a change in concentration of a specific substance (sometimes another hormone)
• Can be stimulated by electrical impulses

Question 4

How do hormones get around the body?

Answer 4

• Diffuse dirrectly into the blood, and are taken around the circulatory system
• They diffuse out of the blood all around the body, but each hormone will only bind to a specific rescptor for that hormone, found on membrane of some cells (target cells)

Question 5

What is the endocrine system responsible for regulating?

Answer 5

-Bodily functions such as growth, metabolism, sleep, reproduction

Question 6

What are the major glands in the system?

Answer 6

• Hypothalamus
• Pituitary gland
• Pineal gland
• Thyroid gland
• Parathyroid gland
• Thymus gland
• Adrenal glands
• Pancreas
• Gonads

Question 7

Function of hypothalamus

Answer 7

-Produces hormones that control the pituitary gland

Question 8

Function of pituitary gland

Answer 8

-Known as the master gland because it releases hormones that control other gland in the endocrine system

Question 9

Function of pineal gland

Answer 9

-Responsible for melatonin production, which plays a key role in sleep patterns

Question 10

Function of thyroid gland

Answer 10

• Produces hormones such as thyroxine.

- responsible for controlling the bodies metabolic rate, as well as growth and maturation

Question 11

Function of parathyroid glands

Answer 11

• Produces parathyroid hormone

- Helps control levels of minerals in the body e.g. calcium

Question 12

Function of thymus gland

Answer 12

-Regulates immune system

Question 13

Function of adrenal glands

Answer 13

• Produces hormones such as adrenaline

- Responsible for flight or fight response

Question 14

Function of pancreas

Answer 14

-Releases hormones insulin and glucagon, which regulates blood sugar level

Question 15

Function of gonads

Answer 15

• Produces sex hormones e.g. testosterone and oestrogen

- These are important in reproduction and the development of sex organs and secondary sexual characteristics

Question 16

What is ‘fight or flight’?

Answer 16

• When the body is threatened it responds by preparing for action.
• Cooridinated by the hypothalamus

Question 17

Describe the activation of the fight or flight repsonse

Answer 17

• Initial shock response
• Hypothalamus triggers activity in the sympathetic branch of ANS
• This stimulates the adrenal medulla within the adrenal glands, which releases adrenaline and noradrenaline into the bloodstream
• Hormones put body into fight or flight mode
• The result of these changes is that the body is ready to use energy to deal ith stressful situation.

Question 18

How do the ‘flight or fight’ affect the body?

Answer 18

• Blood pressure and heart rate increase to get blood quickly to areas of the body that need it.
• Digestion decreases so that blood can be directed to the brain and muscles.
• Muscels get tense so body is physically responsive
• Perspiration increases so body can cool down
• Breathing rate increases so more oxyen can be sent to muscels
• Pupil size increases so more light can enter eye for clearer vision
• Salivation decreases as digestive system isn’t needed