Topic 8

Question 1

Describe the role of
circulating (blood) and local
hormones.

Answer 1

Hormones are secreted by endocrine glands to regulate and coordinate a range of bodily functions. Release of most hormones occurs in short bursts,
although some are secreted over longer periods of time in order to stimulate permanent changes to the body.
Hormones affect only specific target cells by (chemically) binding to specific receptors. Circulating hormones travel around the body in the blood. Examples include adrenaline and testosterone.
Local hormones act on neighbouring cells without entering the bloodstream and are usually inactivated quickly. Examples include glucagon and serotonin.

Question 2

Label the location of the
major endocrine organs in
the human body.

Answer 2

Limit to:
* hypothalamus
* pituitary gland
* pineal gland
* thyroid gland
* adrenal glands
* pancreas
* ovaries and testes

Question 3

Explain how circulating
hormone levels are
regulated.

Answer 3

They are regulated by complex feedback loops
that may be influenced by:
* signals from the nervous system, such as
adrenaline
* chemical changes in the blood, such as
insulin
* other hormones, such as growth hormone.

Question 4

Explain the relationship
between the hypothalamus
and the pituitary gland.

Answer 4

The hypothalamus and the pituitary gland are
together responsible for homeostasis.
* The hypothalamus is the part of the brain
that controls the pituitary gland.
* The pituitary gland is an endocrine
gland located in the brain below the
hypothalamus.
* Neurohormones, such as GHRH and
somatostatin from the hypothalamus,
directly influence the pituitary gland.
* Nerve impulses from the hypothalamus also
stimulate the pituitary gland.
The pituitary gland secretes hormones, such as
Antidiuretic hormone (ADH) and growth hormone
(GH), that help regulate a wide range of bodily
functions including growth, and water and
temperature regulation.