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Which system controls body activities through hormone secretion and has effects that last longer?
Which system controls body activities through hormone secretion and has effects that last longer?
The endocrine system uses neurotransmitters to control bodily functions.
The endocrine system uses neurotransmitters to control bodily functions.
False
What is the primary function of hormones in the body?
What is the primary function of hormones in the body?
To regulate various physiological processes such as metabolism, growth, and development.
Exocrine glands secrete their products into ________ which carry the secretions to the target site.
Exocrine glands secrete their products into ________ which carry the secretions to the target site.
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Match the following glands with their characteristics:
Match the following glands with their characteristics:
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What type of gland secretes hormones directly into the bloodstream?
What type of gland secretes hormones directly into the bloodstream?
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Hormones can facilitate the contraction of smooth muscles.
Hormones can facilitate the contraction of smooth muscles.
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Name one role of hormones in the immune system.
Name one role of hormones in the immune system.
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What is the main function of Human Growth Hormone (hGH)?
What is the main function of Human Growth Hormone (hGH)?
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Exocrine glands release hormones directly into the bloodstream.
Exocrine glands release hormones directly into the bloodstream.
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Which of the following glands is considered a major endocrine gland?
Which of the following glands is considered a major endocrine gland?
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What disease occurs due to the pituitary's inability to secrete ADH?
What disease occurs due to the pituitary's inability to secrete ADH?
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All hormones are steroids.
All hormones are steroids.
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The pituitary gland is mainly controlled by the ______.
The pituitary gland is mainly controlled by the ______.
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Match the glands with their secretion methods:
Match the glands with their secretion methods:
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What are the fundamental building blocks of protein hormones?
What are the fundamental building blocks of protein hormones?
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Steroid hormones can be taken ______ because they are lipid-soluble.
Steroid hormones can be taken ______ because they are lipid-soluble.
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Match the following hormones with their type:
Match the following hormones with their type:
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What is the role of cyclic AMP in hormone action?
What is the role of cyclic AMP in hormone action?
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Hormones are secreted in a constant stream to maintain homeostasis.
Hormones are secreted in a constant stream to maintain homeostasis.
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List two methods that regulate hormone secretion.
List two methods that regulate hormone secretion.
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The cells that have receptor sites for a specific hormone are part of the ______ tissue for that hormone.
The cells that have receptor sites for a specific hormone are part of the ______ tissue for that hormone.
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Which of the following is a characteristic of protein hormones?
Which of the following is a characteristic of protein hormones?
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What is the effect of Melanocyte-stimulating hormone (MSH) on the body?
What is the effect of Melanocyte-stimulating hormone (MSH) on the body?
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Dwarfism is caused by an excess of human growth hormone (hGH) in children.
Dwarfism is caused by an excess of human growth hormone (hGH) in children.
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What hormone is primarily responsible for stimulating uterine contractions during childbirth?
What hormone is primarily responsible for stimulating uterine contractions during childbirth?
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The disorder caused by insufficient ADH, leading to excessive water loss in urine, is known as __________.
The disorder caused by insufficient ADH, leading to excessive water loss in urine, is known as __________.
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Match the hormones with their function:
Match the hormones with their function:
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What is a common clinical application of synthetic oxytocin (Pitocin)?
What is a common clinical application of synthetic oxytocin (Pitocin)?
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Excessive ADH secretion can lead to increased blood pressure due to blood vessel constriction.
Excessive ADH secretion can lead to increased blood pressure due to blood vessel constriction.
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What role do neurosecretory cells in the hypothalamus play?
What role do neurosecretory cells in the hypothalamus play?
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Which hormone causes calcium to be released from bone into the blood?
Which hormone causes calcium to be released from bone into the blood?
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Positive feedback mechanisms decrease the output of hormones in response to a stimulus.
Positive feedback mechanisms decrease the output of hormones in response to a stimulus.
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What are the two lobes of the pituitary gland?
What are the two lobes of the pituitary gland?
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During childbirth, oxytocin stimulates uterine ______.
During childbirth, oxytocin stimulates uterine ______.
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What is the primary function of Adrenocorticotropic Hormone (ACTH)?
What is the primary function of Adrenocorticotropic Hormone (ACTH)?
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The hypothalamus serves as a link between the nervous and endocrine systems.
The hypothalamus serves as a link between the nervous and endocrine systems.
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What is the major role of the Thyroid Stimulating Hormone (TSH)?
What is the major role of the Thyroid Stimulating Hormone (TSH)?
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Match the anterior pituitary hormone with its function:
Match the anterior pituitary hormone with its function:
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The anterior pituitary is responsible for releasing hormones that regulate growth, metabolism, and ______.
The anterior pituitary is responsible for releasing hormones that regulate growth, metabolism, and ______.
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Which of the following hormones is produced by the posterior pituitary?
Which of the following hormones is produced by the posterior pituitary?
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Study Notes
Hormone Inhibition by Steroids
- Steroids can inhibit the production of natural hormones.
Endocrine System
- The nervous and endocrine systems work together to control bodily functions.
- Endocrine glands release hormones into the bloodstream.
- The glands in the endocrine system are small but important.
- Endocrine glands are scattered throughout the body.
Learning Outcomes
- Students should be able to compare the nervous and endocrine systems.
- Students should be able to describe the function of hormones.
- Students should be able to outline the organization of endocrine glands and their component glands.
- Students should be able to describe general hormone characteristics and the three mechanisms that regulate hormone secretion.
- Students should understand the location and relationship of the hypothalamus and pituitary gland.
- Students should be able to describe the function of hormones secreted by the pituitary gland.
Introduction
- Nervous and endocrine systems work together to coordinate body functions.
- Endocrine glands secrete hormones into the bloodstream.
- Endocrine glands are small but important.
Comparison Between Nervous & Endocrine Systems
-
Nervous system:
- Controls bodily activities through nerve impulses and neurotransmitters.
- Effects are short-lived (seconds) and localized.
- Controls muscle contractions or glandular secretions.
- Nervous system parts stimulate or inhibit hormone release.
-
Endocrine system:
- Controls bodily activities by releasing hormones.
- Effects are longer-lasting and more generalized.
- Influences growth, development, and metabolic activities.
- Can promote or inhibit nerve impulses.
Summary of Nervous & Endocrine System Comparison
- Signals: the nervous system uses electrical impulses (action potentials); the endocrine system uses chemical impulses (hormones).
- Pathways: nervous system uses neurotransmitters; endocrine system uses blood transport.
- Speed of Information: nervous system is fast; endocrine system is slow.
- Duration of Effect: nervous system is short-lived; endocrine system can be short or long-lived.
- Type of Action/Response: nervous system can be voluntary or involuntary; endocrine system is usually involuntary.
- Target: nervous system targets localized cells connected to neurons; endocrine system often targets distant cells.
Functions of Hormones
- Regulate chemical composition and volume of internal environment (interstitial fluid)
- Regulate metabolism and energy balance
- Regulate smooth and cardiac muscle fiber contractions
- Control secretions by other glands
- Regulate immune system activities
- Regulate growth and development
- Regulate reproductive system function
- Regulate circadian rhythm
Types of Glands
- Exocrine glands: secrete their products into ducts that carry secretions to a target site (e.g., sweat glands, sebaceous glands, mammary glands, digestive glands).
- Endocrine glands (ductless glands): secrete hormones directly into blood capillaries or lymph, circulating them throughout the body.
Endocrine Glands
- Lists the major and minor endocrine glands (e.g., pituitary, thyroid, parathyroid, adrenal, pancreas, ovaries, testes, thymus, pineal).
Other Hormone-Producing Structures
- Structures outside the official endocrine system but producing hormones: Kidneys, gastrointestinal mucosa, skin, liver, small intestine, placenta, and atrial muscle cells (ANP).
Recap - Organ Producing Hormones
- Lists the hormones produced by different organs.
Chemical Nature of Hormones
- Hormones are proteins or steroids.
- Most hormones are proteins or protein derivatives and have receptors on the cell membrane.
- Difficult to administer orally because they are inactivated by stomach acid and pepsin, thus must be injected (e.g., insulin, glucagon, adrenaline, noradrenaline).
- Steroid hormones (e.g., glucocorticoids, mineralocorticoids, thyroid hormones) are derived from lipids and have receptors inside the cell.
- Lipid-soluble steroid hormones can be taken orally.
Mechanisms of Hormone Action
- Hormones circulate throughout the body in the blood.
- Hormones affect only specific cells with receptor sites that match.
- A hormone binding to its receptor can activate an enzyme, leading to a second messenger (e.g., cyclic AMP), affecting cellular functions or causing protein production.
- Steroid hormones bind within the cell to activate receptors, alter gene expression, and create new proteins.
Summary of Hormone Action
- Describes the two main mechanisms of hormone receptor interactions—protein hormones binding on the cell membrane, and steroid hormones binding inside the cell.
Control of Hormone Secretion
- Most hormones are released in short bursts with little or no release between bursts to control blood concentration.
- The regulation of hormone secretion maintains homeostasis.
- Disorders can occur if regulatory mechanisms do not function properly.
Control of Hormone Secretion (continued)
- Hormone secretion is regulated by neural stimulus, humoral stimulus, or hormonal stimulus.
Neural Stimulus
- Nerve fibers stimulate the release of hormones (e.g., norepinephrine, epinephrine during stress).
Humoral Stimulus
- Changes in blood ions or nutrient levels stimulate hormone release (e.g., parathyroid hormone and ADH).
Hormonal Stimulus
- Some hormones released stimulate the release of other hormones (e.g., hypothalamus triggering anterior pituitary).
Control of Hormone Secretion (continued)
- Most hormonal systems operate via negative feedback; some use positive feedback.
- Negative feedback mechanisms respond to hormone levels to regulate the output and maintain homeostasis when hormone levels are high or low.
Negative Feedback Example
- Parathyroid hormone (PTH), regulated by blood calcium levels (negative feedback).
Negative Feedback Example (continued)
- Calcitonin acts inversely with PTH, lowering blood calcium levels when high.
Positive Feedback Example
- Oxytocin release during childbirth, where uterine contractions stimulate further oxytocin release.
The Hypothalamus and Pituitary Gland
- The hypothalamus is the major link between the nervous and endocrine systems.
- The hypothalamus regulates virtually all aspects of growth, development, metabolism, and homeostasis.
- The hypothalamus receives input from many brain areas, like the thalamus and limbic system.
The Hypothalamus and Pituitary Gland (continued)
- The pituitary gland is attached to the hypothalamus and has anterior and posterior lobes.
- Release and inhibiting hormones of the hypothalamus control pituitary hormones.
Hypothalamus and Pituitary Gland (continued)
- Anterior pituitary: adenohypophysis; about 75% of the pituitary's weight; a distinct gland.
- Posterior pituitary: neurohypophysis; extension of the brain; consists of neurons and neuroglia.
Hypothalamus and Anterior Pituitary Lobe
- Neurosecretory cells in the hypothalamus secrete hormones into capillaries, and they travel via veins to the anterior pituitary, affecting glandular epithelium.
- Releasing and inhibitory hormones affect anterior pituitary function.
Anterior Pituitary Hormones
- Human Growth Hormone (hGH): stimulates bone, muscle, and organ growth by promoting protein synthesis.
- Thyroid Stimulating Hormone (TSH): stimulates thyroid hormones secretion.
- Prolactin (PRL): stimulates breast development and milk production.
Anterior Pituitary Hormones (continued)
- Follicle-Stimulating Hormone (FSH): stimulates egg and sperm development.
- Luteinizing Hormone (LH): stimulates ovulation and the production of estrogen and progesterone (female) and testosterone (male).
Anterior Pituitary Hormones (continued)
- Adrenocorticotropic Hormone (ACTH): controls glucocorticoid secretion by the adrenal cortex.
- Melanocyte-Stimulating Hormone (MSH): stimulates melanin production in skin and hair; may affect appetite and sexual arousal.
Anterior Pituitary Hormones (Clinical Applications)
- Dwarfism: lack of hGH in childhood.
- Giantism: excessive hGH in childhood.
- Acromegaly: excessive hGH in adulthood.
Hypothalamus and Posterior Pituitary Gland:
- Posterior pituitary (neurohypophysis) is an extension of the hypothalamus.
- Neurosecretory cells in the hypothalamus synthesize oxytocin and antidiuretic hormone (ADH).
- These hormones are stored in axon terminals in the posterior pituitary and released into the bloodstream.
Hypothalamus and Posterior Pituitary Gland (continued)
- Oxytocin: targets smooth muscle in the uterus and breasts, stimulating uterine contractions, milk ejection, and other bodily processes.
- Antidiuretic Hormone (ADH): promotes water reabsorption in kidney tubules and reduces water loss through sweat glands.
Hypothalamus and Posterior Pituitary Gland (Regulation of ADH Secretion):
- Blood osmotic pressure regulation of ADH release (negative feedback).
- High blood osmotic pressure triggers ADH release.
- Low blood osmotic pressure inhibits ADH release.
Regulation of Oxytocin Secretion (Positive Feedback):
- Stretch receptors in the cervix stimulate oxytocin, initiating contractions during childbirth.
- Contractions further stimulate more oxytocin release.
Posterior Pituitary Hormones (Clinical Applications)
- Insufficient ADH (Diabetes Insipidus): excessive water loss in urine leading to dehydration and thirst.
- Excessive ADH: constricted blood vessels and elevated blood pressure.
Recap/Quiz
- Summarizes the key concepts of nervous and endocrine functions, including their coordinated actions, types of glands, hormonal regulation, and examples of specific hormones' actions and effects.
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Description
Test your knowledge on the endocrine system and its functions. This quiz covers the role of hormones, gland characteristics, and their effects on the body. Answer questions related to hormonal secretion and its impact on bodily activities.
