ENDOCYNE SYSTEM Flashcards
The Function of the Endocrine System
The human endocrine system is composed of glands that secrete chemicals called hormones directly into the bloodstream
The blood carries the hormone around the body, and when it reaches a target cell/organ it produces an effect
Compared to the nervous system the effects of hormones are slower but they act for longer
Important structures in the endocrine system are:
Pituitary gland: a ‘master gland’ making hormones such as FSH and LH
Pancreas: produces insulin which regulates the blood glucose level
Thyroid: produces thyroxine which controls the metabolic rate and affects growth
Adrenal glands: produces adrenaline
Ovaries (females): produce estrogen
Testes (males): produce testosterone
The major endocrine glands in the body, IGCSE & GCSE Biology revision notes
The major endocrine glands in the body secrete hormones which circulate around the body in the bloodstream
Pituitary Gland
The pituitary gland in the brain is a ‘master gland’ which secretes several hormones into the blood in response to body conditions
These hormones in turn act on other glands to stimulate other hormones to be released to bring about effects
For example, in certain conditions, the pituitary gland makes and secretes thyroid-stimulating hormone (TSH) which stimulates the thyroid to release thyroxine
How hormones work, IGCSE & GCSE Biology revision notes
Hormones are synthesized and released into the bloodstream from a gland (such as the pituitary gland) and circulate in the bloodstream, having an effect on target cells
Glands & Hormones
Endocrine glands synthesise substances such as hormones and release them into the bloodstream
Hormones are chemical substances that circulate in the bloodstream and only affect target organs
They are produced in large quantities and can be very powerful
They control ongoing internal functions and enable our bodies to react according to changes in the environment
Pituitary Gland
The pituitary gland is often referred to as the ‘master gland’ because it controls the production and release of other hormones from other glands in the endocrine system
It is controlled by the hypothalamus
The anterior lobe releases an adrenocortical trophic hormone (ACTH), which stimulates the adrenal cortex and the release of cortisol
The posterior lobe released oxytocin, which is responsible for uterus contractions during childbirth.
Oxytocin helps regulate our emotional responses and pro-social behaviours, including trust, empathy, and the processing of bonding cues
Pineal Gland
This releases melatonin which is responsible for important biological rhythms, including the sleep-wake cycle
It receives information from the environment about the light-dark cycle which influences the production and secretion of melatonin
pineal-gland-6-2-2-aqa-a-level-psychology
Thyroid Gland
This plays a role in controlling heart, muscle and digestive function, brain development and bone maintenance
It releases thyroxine, which is responsible for regulating our metabolism through other organs like the liver and kidneys
Our metabolism is involved in chemical processes of converting food into energy
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Pancreas Gland
This plays a signficant role in digestion by producing enzymes to break down food and hormones to help regulate blood-sugar levels and appetite
The main hormone it produces is insulin
Insulin helps your body break down carbohydrates to produce glucose, which we use for energy
Without insulin, we cannot break down glucose properly, which can cause blood-sugar levels to rise and increase the risk of diabetes
pancreas-gland-6-2-2-aqa-a-level-psychology
Andrenal Gland
The adrenal gland is divided into two parts, the adrenal medulla and adrenal cortex
The adrenal medulla releases adrenaline and noradrenalin which play a key role in ‘fight or flight’ repsonse
The adrenal cortex releases cortisol which stimulates the release of glucose while suppressing the immune system
adrenal-gland-6-2-2-aqa-a-level-psychology
Testes
The testes release androgens, which include the main hormone testosterone
Testosterone is responsible for the development of male sex characteristics during puberty, including muscle growth, fat distribution and sperm production
testes-6-2-2-aqa-a-level-psychology
Ovaries
The ovaries release oestrogen which controls the regulation of the female reproductive system, including the menstrual cycle and pregnancy
tip
Questions about glands are hormones will tend to ask for identification of the gland, along with a description or outline the hormone it produces. For some questions where you are required to ‘explain’ the functions of the gland and/or hormone, you will need to relate this knowledge to what behaviours it can impact.
