Biology: Endocrine Glands and Hormones

This document provides information about the endocrine glands and hormones in biology. It discusses the hormones associated with the pituitary gland, pancreas, and ovaries. It also explains positive and negative feedback mechanisms in homeostasis.

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BIOLOGY
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Activity 1:
Listing of three endocrine gland and the hormones that are associated with those hormones
are as follows (Waters and Jeffreys 2017):
Endocrine Gland Hormones
Pituitary Gland Thyroid stimulating hormones (TSH),
growth hormones (GH), Gonadotropins
(FSH and LH), antidiuretic hormones,
adrenocorticotropic hormone (ACTH),
oxytocin and prolactin.
Pancreas Insulin and glucagon.
Ovaries Oestrogen and progesterone
Activity 2:
Example of each of the below mentioned hormones (Levin 2015):
 Peptide hormones- The primary example of peptide hormone is insulin that regulates
the concentration of glucose within the blood and cells.
 Steroid hormones- Androgens is considered as the male sex hormone and an
example of steroid hormone that is responsible for maintenance and development of
secondary sex traits in male.
Activity 3:
Positive feedback- Positive feedback circle is defined as the process through which the
human body recognizes or senses any change and further activates mechanism, which will
accelerate the change recognized by the body. Example of positive feedback is noticed in the

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process of blood clotting, where a part of complex biochemical process involved in blood
clotting produces an enzymes that result in blood clot matrix that speeds up the process of
thrombin formation. It bears a self-accelerating and self-catalytic effect that enhances the
speed of blood clotting until the bleeding stops completely. Therefore, this entire process of
thrombin formation and inhibition of bleeding is considered as the positive feedback circle
(Takano, Funahashi and Kaibuchi 2019).
Negative feedback- The general homeostasis is regulated through mechanism of negative
feedback loop that function and activate when the human body recognizes any change and
reverse the change to maintain the homeostasis. Example of negative feedback is regulation
of body temperature where the temperature of human body rises and negative feedback loop
is activated that dilates the blood vessels therefore radiating excess heat from the human body
in form of sweat. Therefore, this activation of negative feedback loop will help the human
body to regulate the body temperature when any change is triggered by the brain (Takano,
Funahashi and Kaibuchi 2019).
Activity 4:
Homeostasis is disturbed when the body temperature rises from normal and thus
activates negative feedback system that will regulate the body temperature and return it to
normal. The specialized neurons present within the hypothalamus in the brain receives the
temperature change and thus act as stimulus, which further pass the message of temperature
change to the nerve centre that further send signal to the skin blood vessels’. The temperature
change is detected by the temperature receptors that further send the signal to the nerve
impulse present in the brain. The hypothalamus present in the brain is triggered or stimulated
and therefore transmit the nerve impulses to the appropriate body parts (Morrison 2016). The
blood vessels dilates and result in excess heat loss in form of sweat that is triggered due to

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negative feedback system and therefore result in lower heat production. The metabolic rate of
the individual is decreased and therefore reduces the heat production and hence the body
temperature is regained to the normal level. Therefore, it is established that if the body
temperature changes, negative feedback loop is activated that will send signal to
hypothalamus and instruct them to later the body temperature and regain it to normal balance.

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References
Levin, E.R., 2015. Extranuclear steroid receptors are essential for steroid hormone actions.
Annual Review of Medicine, 66, pp.271-280.
Morrison, S.F., 2016. Central control of body temperature. F1000Research, 5.
Takano, T., Funahashi, Y. and Kaibuchi, K., 2019. Neuronal polarity: positive and negative
feedback signals. Frontiers in cell and developmental biology, 7, p.69.
Waters, D. and Jeffreys, A.B., 2017. Endocrine system. In Atlas of feline anatomy for
veterinarians (pp. 139-146). Teton NewMedia.