Endocrine System - Hormonal Control and Glands

What's the Point?

By the end of this lesson, you will be able to describe how the endocrine system regulates body functions through hormones, identify major endocrine glands and their roles, and explain how this system works with the nervous system to maintain homeostasis.

Your body is constantly sending and receiving information. The nervous system is your body’s control and communication network—it helps you think, feel, move, and react to your environment. It allows instant communication between the brain, spinal cord, and the rest of the body.

Explore each section in the tabs below to learn more.

Jordan
Maya

Continue the journey by choosing either Jordan or Maya from the tabs above.

Jordan's Story

Person consulting with their physician, full text available below image

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During recovery, Jordan’s doctor monitors his energy levels and blood sugar. These are regulated by hormones like insulin and adrenaline. His endocrine system must coordinate carefully with his nervous and muscular systems to rebuild strength without exhausting his body.

Maya's Story

Three people running a race on a city street, full text available below image

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Maya’s endocrine system keeps her performance steady. When she starts a race, adrenal glands release adrenaline, increasing her heart rate and breathing. Later, her pituitary gland signals other glands to help her recover. These automatic adjustments keep her balanced even under stress.

How the Endocrine System Works

The endocrine system uses glands that produce and release hormones into the bloodstream. Hormones act slowly but have long-lasting effects.

Endocrine System
Gland	Hormone(s)	Main Function
Pituitary	Growth hormone (GH), thyroid-stimulating hormone (TSH)	“Master gland” that controls other glands and regulates growth
Thyroid	Thyroxine	Controls metabolism and energy levels
Parathyroid	Parathyroid hormone	Regulates calcium levels in the blood
Adrenal	Adrenaline (epinephrine), cortisol	Helps the body respond to stress
Pancreas	Insulin, glucagon	Controls blood sugar levels
Ovaries/Testes	Estrogen, testosterone	Regulate reproductive functions and characteristics

Hormonal Control and Feedback

Hormones use a feedback loop to keep the body in balance. This means when a hormone level rises or falls, the body sends signals to increase or decrease production.

Example – Blood Sugar Regulation:

When blood sugar rises, the pancreas releases insulin, which helps cells absorb glucose.
When blood sugar drops, the pancreas releases glucagon to raise it again.
This is called a negative feedback loop, and it keeps the body’s energy level stable.

My Body Tracker – Endocrine System Entry

You will add information about the endocrine system to your ongoing tracker. This entry should include:

- - The major endocrine glands and their hormones
  - An example of a negative feedback loop
  - A short paragraph explaining how the nervous and endocrine systems work together

Connections to Other Systems

Nervous System: Works together with the endocrine system to control responses and release hormones during stress.
Circulatory System: Transports hormones through the bloodstream.
Reproductive System: Depends on hormones for development and function.
Digestive System: Hormones regulate appetite and metabolism.

Jordan’s and Maya’s stories show how the nervous and endocrine systems form the body’s “command center”—one fast, one steady.

Test Yourself

Review what you have learned by completing the activity below.

The endocrine system keeps your internal world in balance. It’s the reason you can grow, adapt, handle stress, and recover. Jordan’s hormone levels help him heal, while Maya’s keep her performance steady. Together with the nervous system, the endocrine system proves that your body is both fast-reacting and finely tuned for long-term stability.

Consider the following...

Think of a time you felt stressed or excited. Which hormones do you think were active, and how did they change your body’s response?

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