Biology: B11- Hormonal Coordination

What are the key glands of the endocrine system?

-pituitary gland

-pancreas

-thyroid

-adrenal gland

-ovaries

-testes

What is the endocrine system?

A system of the glands and organs that make hormones and release them directly into the blood so they can travel to tissues and organs all over the body

What is the role of the Pituitary Gland?

-Controls growth in children

-Stimulates thyriod gland to make thyroxine to control metabolism

-(women) stimulates ovaries to produce and release eggs and make oestrogen

-(men)stimulates testes to make sperm and testosterone

What is the role of the Thyroid?

Controls metabolic rate of the boddy

What is the role of the Pancreas?

Controls the levels of glucose in the blood

What is the role of the Adrenal Gland?

Produces adrenaline to prepare the body for stressful situations (‘fight or flight’ response)

What is the role of the Ovaries and Testes?

Releases hormones involved in puberty and reproduction

What is the key difference between the nervous and endocrine system?

The endocrine systems effects are slower acting but longer lasting

Why is the pituitary gland referred to as the ‘master gland’?

It contains the functions of many other endocrine glands. These glands then stimulate other hormones to be released to bring about effects.

What does the pancreas monitor?

Blood glucose concentration

What happens if somebody’s blood glucose concentration is too high?

-The pancreas produces insulin that causes the glucose to move from the blood into the cells

-In the liver and muscles excess glucose is converted to glycogen for storage

What is type 1 diabetes?

-A disorder where the pancreas fails to produce sufficient insulin

-It is characterized by high blood glucose levels and is normally treated with insulin injections

What is type 2 diabetes?

-The body cells no longer respond to insulin produced by the pancreas.

-Obesity is a risk factor and it is normally treated with carbohydrate-controlled diet and exercise

What are the key differences between type 1 and type 2 diabetes?

-In type 1 the pancreas does not make insulin, in type 2 the pancreas makes less insulin than your body needs

What is glucose?

the sugar used in respiraton

What is glycogen?

A storage carbohydrate found in the liver and muscles

What is glucagon?

A hormone that stimulates the liver to break down glycogen to glucose

What happens if a persons blood glucose concentration is too low?

the pancreas produces the hormone glucagon that causes glycogen to be converted into glucose and released into the blood

What is the role of oestrogen?

-Triggers the development of secondary sexual characteristics (puberty)

-Stimulates build-up and maintenance of uterine lining

-Inhibits release of FSH

-Stimulates the release of LH

What is ovulation?

The time when an egg is released into the uterus (day 14/28)

What is the role of FSH?

-Maturation of the eggs in the ovary

-Stimulates the ovary to produce oestrogen

What is the role of LH?

Stimulates egg release

What is the role of progesterone?

-Stimulates build-up and maintenance of uterine lining

-Inhibits the release of both FSH and LH

What is the role of testosterone?

Stimulates sperm production

What are examples of contraceptive methods?

-Oral Contraceptives

-Injection/implant/skin patch

-Condoms and diaphragms

-Intrauterine devices

-Spermicidal Agents

-Abstinence

-Surgical Sterilisation

How do oral contraceptives work?

Contain hormones to inhibit FSH production so no eggs mature

How do injections/implants/skin patches work?

Slow release if progesterone to inhibit the maturation and release of eggs

How do barrier methods work?

Prevents sperm from reaching the egg

How do Intrauterine devices work?

Prevents implantation of an embryo or release a hormone

How do spermicidal agents work?

Kill or disable sperm

What are some reproductive technologies to treat infertility?

-FSH and LH as a fertility drug

-In Vitro Fertilization (IVF)

How does IVF work?

-Giving the mother FSH and LH to stimulate maturation of several eggs

-Eggs are collected from the mother and fertilized in a laboratory

-The fertilized eggs develop into embryos

-One or two embryos are inserted into the mothers uterus

What are the downsides of IVF?

-Emotionally and physically stressful

-Low success rates

-Multiple births which could risk both the babies and the mother

What is negative feedback?

The action taken by the body to return to the optimum level and to maintain a steady state

What is the role of thyroxine?

-Stimulates the basal metabolic rate

-Growth and development

Where is thyroxine made?

Thyroid Gland

What is the role of adrenaline?

-Increases heart/breathing rate

-Boots delivery of oxygen and glucose to the brain and muscles

-Prepares body for ‘fight or fight’

Where is adrenaline made?

Adrenal gland (in times of fear/stress)

How are thyroxine levels controlled?

Negative feedback

What us phototropism?

A plants response to light

What is gravitropism/geotropism?

A plants response to gravity

How do plants respond to light and gravity?

-Shoots grow towards light and against the force of gravity

-Roots grow in the direction of the force of gravity

What is the consequences of unequal distributions of auxin?

Unequal growth in plant roots/shoots

What is auxin?

A plant hormone that is released to cause plant responses to light and gravity

Why are gibberellins important?

Initiating seed germination

What are auxins used for?

-Weed killers

-Rooting powders

-Promoting growth in tissue culture

What is ethene used for?

Controlling ripening of fruit during storage and transport

What are gibberellins used for?

-Ending seed dormancy

-Promoting flowering

-Increasing food size