Chapter 3 - Endocrine System Flashcards
What are hormones?
Chemical substances produced in minute quantities by endocrine glands
Hormones are transported to target organs by:
blood
What do hormones influence?
They influence growth, development and activity of an organism
What happens to hormones after performing their functions?
They are destroyed in the liver and excreted by the kidneys
How do hormones affect the body?
- Help in the delivery of baby out of the mother’s womb during childbirth
- Result in the increase in height of a child
- Prepare the body for ‘fight’ or ‘flight’ during dangerous encounters
- Responsible for physical and emotional changes during puberty
Why must production of hormones must be carefully controlled?
When too much or too little hormones are produced, the organism will be adversely affected
What happens when there is too little thyroxine in a tadpole?
This will inhibit its grow into a frog
What happens when there is too much thyroxine in a tadpole?
This will turn it into the adult form too quickly, resulting in a tiny frog
Hormone production in the body is controlled by:
- the nervous system
- certain chemical substances (hormones from other endocrine glands)
Where are hormones produced?
In endocrine glands
What happens to hormones after they are produced?
They are released directly into the blood from the endocrine glands
Feature of endocrine glands
Have an extensive network of blood vessels to transport hormones to their target organs
What are the two types of glands?
Endocrine glands and exocrine glands
What are endocrine glands?
Ductless glands that transport their secretions via the bloodstream
What are examples of endocrine glands?
Adrenal glands
Pituitary gland
Pancreas
What are exocrine glands?
Ducts present to transport secretions to target organs
What are examples of exocrine glands?
Sweat glands
Salivary glands
Pancreas
Pituitary gland: regulated by
Hypothalamus
- regulates the secretion of some pituitary hormones
Pituitary gland: hormone(s) secreted
Growth hormone (GH) Antidiuretic hormone (ADH) Thyroid-stimulating hormone (TSH)
Pituitary gland: special feature
Secretes hormones that control the functions of several other endocrine glands
Thyroid gland: stimulated by
Thyroid stimulating hormone (TSH)
- secreted by the pituitary gland
Thyroid gland: hormone(s) secreted
Thyroxine