Hormones

Give an example of an effector.

A muscle or a gland.

How are soluble chemical substances carried around the body?

Via blood.

Define hormones.

Chemical messengers that are carried in the blood and released from endocrine glands.

What does the pancreas do?

Regulates blood glucose.

Define target organ.

The organ affected by a specific hormone.

Why is a reflex arc an automatic behaviour?

It doesn’t involve the brain.

Name something in the body affected by growth hormone.

Muscles, bones and intestines.

Name a condition in the body that needs to be controlled.

Glucose levels, salt levels, and temperature.

Define homeostasis.

Maintaining constant conditions inside the body.

What is the target organ of insulin?

The liver.

What effect does type 2 diabetes have on blood glucose and why?

Blood glucose would increase as the insulin-releasing cells wouldn’t be working properly.

How is type 1 diabetes treated?

Insulin is injected into the body.

How is type 2 diabetes treated?

Positive changes in diet and exercise levels.

Define metabolic rate.

The rate at which chemical energy is transferred by your bodily reactions.

Define resting metabolic rate.

The metabolic rate when the body is at rest.

Define thyroxine.

A hormone which affects metabolic rate by changing how certain cells work.

Define negative feedback.

A control mechanism that reacts to changes in the body by bringing the condition back down to a normal level.

Define glycogen.

A storage material made from glucose.

Define fight or flight.

A sudden automatic response to danger.

What does the pancreas produce?

Insulin and glucagon.

What is the cause of type 1 diabetes?

The cells in the pancreas that produce insulin are destroyed by the immune system and blood glucose levels rise out of control.

What is the cause of type 2 diabetes?

The liver cells become resistant to insulin and not enough is being produced.

Explain the negative feedback loop of thyroxine.

TRH is released from the hypothalamus, which travels to the pituitary gland which produces TSH, which travels to the thyroid gland which produces thyroxine.

Explain how adrenalin can affect the body.

The heart muscles contract faster and more strongly, heart rate and blood pressure increase

Liver cells change glycogen to glucose and release it, increasing blood sugar concentration.

Define menstruation.

The breakdown and loss of the uterus lining.

What happens in days 1-5 of the menstrual cycle?

Menstruation, where the uterus lining breaks down and is lost with the unfertilised egg.

What happens in days 6-12 of the menstrual cycle?

Egg cells start to mature and the uterus lining begins to build up.

What happens on day 14 of the menstrual cycle?

Ovulation, an egg is released from the ovary.

What happens in days 16-28 of the menstrual cycle?

The uterus lining continues to thicken and the cycle restarts if a fertilised egg isn’t implanted.

What is the most fertile day of the menstrual cycle?

Day 19.

What does FSH do and where is it produced?

In the pituitary gland, it stimulates egg growth and causes the release of oestrogen.

What does LH do and where is it produced?

In the pituitary gland, and it causes ovulation.

What does oestrogen do and where is it produced?

In the ovaries, it thickens the uterus lining, stops the release of FSH and stimulates the release of LH.

What does progesterone do and where is it produced?

In the corpus luteum, it maintains the uterus lining and stops LH and FSH release.

Where does fertilisation occur?

The fallopian tubes.

What order are hormones released during the menstrual cycle?

FSH, oestrogen, LH, progesterone.

What causes menstruation?

Falling oestrogen and progesterone levels.

What is clomifene therapy?

Therapy for those who don’t release many eggs that increases the concentration of FSH and LH in the blood.

How does IVF work?

The woman’s cycle is stopped, she is given a large amount of LH so lots of eggs are released at the same time, then given progesterone so the uterus lining thickens in preparation for fertilisation, and then she is given a large amount of FSH so many egg cells grow and mature in both ovaries.