11 Questions
What is the primary function of hormones in the body?
To maintain the internal environment of the body within a normal range
Which type of hormone is derived from cholesterol?
Steroid
What is the term for the study of hormones?
Endocrinology
Which organ contains only endocrine cells and is responsible for growth and development?
Pituitary gland
What is the term for the ability of the body to regulate its internal environment despite changes in the external environment?
Homeostasis
What type of stimuli can cause the secretion of hormones in response to changes in the blood?
Humoral stimuli
What is the purpose of negative feedback loops in hormone secretion?
To maintain hormone concentration within a certain range
Where is the pituitary gland located?
In the sella turcica of the sphenoid bone
What is the function of the superior hypophyseal artery?
To supply the anterior lobe of the pituitary gland
What is the function of tropic hormones?
To regulate the secretion of hormones by other endocrine glands
How many different hormones are produced by the anterior pituitary gland?
7
Study Notes
Endocrine System
- A group of ductless glands that secrete messenger molecules called hormones
- Hormones are secreted by cells into the extracellular space and enter capillaries, eventually reaching target cells with specific receptors to create a physiological response
Functions of Hormones
- Help maintain the body's internal environment (homeostasis) within a normal range
- Regulate growth, development, reproduction, stress response, blood chemistry, and metabolic rate
Types of Endocrine Organs
Pure Endocrine Organs
- Pituitary gland
- Pineal gland
- Thyroid gland
- Parathyroid gland
- Adrenal glands
Organs with Both Endocrine and Non-Endocrine Functions
- Pancreas (endocrine and digestive functions)
- Thymus (endocrine and immune functions)
- Gonads (endocrine and reproductive functions)
- Hypothalamus (neuroendocrine functions)
Organs with Some Endocrine Cells
- Heart
- Digestive tract
- Kidneys
- Osteoblasts
- Adipose cells
- Keratinocytes
Classes of Hormones
Amino Acid-Based Hormones
- Amines
- Peptides
- Proteins
Steroid Hormones
- Lipid-based molecules derived from cholesterol
Control of Hormone Secretion
Humoral Stimuli
- Hormone secretion in response to changes in blood ion and nutrient levels
Neural Stimuli
- Nerve fibers stimulate endocrine glands to secrete hormones
Hormonal Stimuli
- Hormones from one endocrine gland stimulate another endocrine gland to secrete hormones
Hormone Regulation
- Feedback loops: negative and positive
- Negative feedback loop: hormone concentration is regulated to maintain a certain range
- Positive feedback loop: increased hormone concentration stimulates further secretion
Pituitary Gland (Hypophysis)
- Located in the sella turcica of the sphenoid bone
- Composed of anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis)
- Anterior lobe supplied by the superior hypophyseal artery
- Posterior lobe supplied by the inferior hypophyseal artery
- Contains 5 cell types, each clustered together, secreting 7 different hormones
- 4 tropic hormones regulate secretion of hormones by other endocrine glands
- 3 hormones act on neuroendocrine target tissues
Test your knowledge of the endocrine system, a group of ductless glands that produce hormones, playing a crucial role in maintaining homeostasis and regulating various physiological processes. Learn about the functions of hormones, their secretion, and their effects on target cells. Explore the importance of the endocrine system in growth, development, reproduction, and stress response.
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