Endocrine System
Use multiple websites, including the one given below to answer the following questions.
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/human/
hormonesrev1.shtml
1. What is the function of the endocrine system? What makes up the endocrine
system?
The endocrine system, made up of all the body's different hormones, regulates all biological
processes in the body from conception through adulthood and into old age, including the
development of the brain and nervous system, the growth and function of the reproductive
system, as well as the metabolism and blood sugar. The endocrine system consists of:
Glands located throughout the body; Hormones made by the glands and released into the
bloodstream or the fluid surrounding cells; and. Receptors in various organs and tissues that
recognize and respond to the hormones.
2. What are hormones and what do hormones do?
A hormone is a chemical substance, produced by a gland and carried in the bloodstream,
which alters the activity of specific target organs. An example of this is the release of the
hormone adrenaline, which is released by the adrenal gland. One of its target organs is the
heart, where it increases the heart rate. Once a hormone has been used, it is destroyed by
the liver. Hormones can control the body, and the effects are much slower than the nervous
system, but they last for longer.
3. Complete the table below:
Name of Gland Hormone(s) Secreted Function of each
hormone secreted by this
gland
Pituitary Growth Hormone Stimulates growth
Thyroid Stimulating Stimulates the thyroid
Hormone gland
Prolactin Stimulates the adrenal
glands
Oxytocin Stimulates uterine
contractions
Thyroid Thyroxine Regulates metabolism
Calcitonin Regulates calcium levels
Pancreas Insulin Lowers blood sugar levels
Glucagon Raises blood sugar levels
Adrenal Cortisol Regulates metabolism
Aldosterone Regulates salt and water
balance
Adrenaline Prepares the body for
Noradrenaline fight or flight
Testes Testosterone Promotes the
development of male
reproductive tissues
Ovaries Estrogen Regulates the menstrual
Progesterone cycle
Prepares the uterus for
pregnancy
4. What is homeostasis? Outline the role that the endocrine system has in
maintaining homeostasis.
Homeostasis is the body's ability to maintain a stable internal environment. The endocrine
system regulates this balance by releasing hormones that control various bodily functions
and ensure optimal conditions for cells.
The endocrine system plays a crucial role in maintaining homeostasis by releasing hormones
that regulate and coordinate the activities of various organs and systems throughout the
body.
5. Explain how glands in the endocrine system maintains the following:
a. Water content:
The endocrine system, via ADH, regulates water balance by controlling kidney reabsorption,
preventing dehydration.
b. Salt content:
Adrenal glands release aldosterone, regulating sodium levels in the kidneys, crucial for
maintaining salt balance.
c. Temperature:
Thyroid hormones influence metabolism, aiding in heat production or conservation to
regulate body temperature.
d. Blood sugar levels:
The pancreas releases insulin to lower blood sugar after meals and glucagon to raise it
between meals, ensuring glucose homeostasis.
Characteristic Nervous System Endocrine System
Rapid electrical impulses through
Mode of Communication neurons Slow chemical signalling through hormones
Synaptic transmission (across
Transmission synapses) Hormones released into the bloodstream
Speed of Response Rapid, milliseconds to seconds Slower, seconds to minutes
Duration of Action Short-lived, milliseconds to minutes Longer-lasting, minutes to days
Specific target cells through Target cells throughout the body via
Target Cells synapses bloodstream
Response Type Localized and specific General and widespread
Immediate, precise control of More prolonged, general control over bodily
Control of Function specific activities functions
Neurotransmitters (e.g., dopamine,
Examples of Messengers serotonin) Hormones (e.g., insulin, adrenaline)
Major Organs Brain, spinal cord, nerves Glands (e.g., pituitary, thyroid, adrenal), organs
Characteristic Nervous System Endocrine System
(e.g., pancreas, ovaries)
Adaptation to Stimuli Rapid adaptation Slow adaptation
Immediate "fight or flight" Prolonged stress response, including cortisol
Response to Stress response release
