Podcast
Questions and Answers
Which of the following mechanisms is most critical for fine-tuning hormone levels and preventing excessive hormonal activity?
Which of the following mechanisms is most critical for fine-tuning hormone levels and preventing excessive hormonal activity?
- Synchronized hormone secretion
- Positive feedback amplification
- Negative feedback control (correct)
- Pulsatile hormone release
Steroid hormones, being lipophilic, typically dissolve freely in the bloodstream, negating the need for carrier proteins during transport.
Steroid hormones, being lipophilic, typically dissolve freely in the bloodstream, negating the need for carrier proteins during transport.
False (B)
How do neurosecretory cells integrate the nervous and endocrine systems?
How do neurosecretory cells integrate the nervous and endocrine systems?
Neurosecretory cells produce hormones and secrete them into the blood, allowing neural signals to regulate hormonal responses.
The synthesis of steroid hormones occurs ______, whereas peptide hormones are synthesized and stored for later release.
The synthesis of steroid hormones occurs ______, whereas peptide hormones are synthesized and stored for later release.
Match each hormone with its primary chemical classification:
Match each hormone with its primary chemical classification:
Which characteristic distinguishes endocrine glands from exocrine glands?
Which characteristic distinguishes endocrine glands from exocrine glands?
The diurnal rhythm of hormone secretion implies that hormone release is constant and unaffected by daily environmental cues.
The diurnal rhythm of hormone secretion implies that hormone release is constant and unaffected by daily environmental cues.
What role does the hypothalamus play in regulating the endocrine system?
What role does the hypothalamus play in regulating the endocrine system?
Hormones that bind to ______ receptors typically induce a rapid response, while those that bind to intracellular receptors often lead to a slower response through gene transcription.
Hormones that bind to ______ receptors typically induce a rapid response, while those that bind to intracellular receptors often lead to a slower response through gene transcription.
Match the hormone with its primary function related to calcium regulation:
Match the hormone with its primary function related to calcium regulation:
Which hormone directly stimulates the synthesis and secretion of thyroid hormones?
Which hormone directly stimulates the synthesis and secretion of thyroid hormones?
Melatonin, secreted by the pineal gland, primarily functions in regulating blood glucose levels.
Melatonin, secreted by the pineal gland, primarily functions in regulating blood glucose levels.
How does the pancreas function as both an endocrine and exocrine gland?
How does the pancreas function as both an endocrine and exocrine gland?
In the adrenal gland, the adrenal cortex primarily produces ______, whereas the adrenal medulla mainly releases ______.
In the adrenal gland, the adrenal cortex primarily produces ______, whereas the adrenal medulla mainly releases ______.
Match each hormone with its primary effect.
Match each hormone with its primary effect.
Which of the following hormones directly influences growth and metabolism by stimulating growth factor secretion from the liver?
Which of the following hormones directly influences growth and metabolism by stimulating growth factor secretion from the liver?
The heart functions solely as a mechanical pump and has no endocrine function.
The heart functions solely as a mechanical pump and has no endocrine function.
Describe the roles of inhibin in both males and females.
Describe the roles of inhibin in both males and females.
1,25-dihydroxy-vitamin D3, synthesized in the ______, plays a critical role in increasing ______ absorption in the intestine.
1,25-dihydroxy-vitamin D3, synthesized in the ______, plays a critical role in increasing ______ absorption in the intestine.
Match each adipose tissue hormone with its general role in the body.
Match each adipose tissue hormone with its general role in the body.
Flashcards
Melatonin
Melatonin
Regulates circadian rhythms, immune function, and acts as an antioxidant.
Oxytocin
Oxytocin
Stimulates milk ejection, uterine contractions during labor, and influences behavior.
Vasopressin (ADH)
Vasopressin (ADH)
Increases water reabsorption in the kidneys.
Prolactin
Prolactin
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Growth Hormone
Growth Hormone
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Corticotropin (ACTH)
Corticotropin (ACTH)
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Follicle-Stimulating Hormone (FSH)
Follicle-Stimulating Hormone (FSH)
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Luteinizing Hormone (LH)
Luteinizing Hormone (LH)
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Triiodothyronine and Thyroxine (T3 & T4)
Triiodothyronine and Thyroxine (T3 & T4)
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Parathyroid Hormone (PTH)
Parathyroid Hormone (PTH)
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Atrial Natriuretic Peptide (ANP)
Atrial Natriuretic Peptide (ANP)
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Angiotensinogen
Angiotensinogen
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Insulin
Insulin
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Glucagon
Glucagon
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Aldosterone
Aldosterone
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Epinephrine
Epinephrine
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Vitamin D3
Vitamin D3
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Androgens
Androgens
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Estrogen
Estrogen
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Relaxin
Relaxin
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Study Notes
- Endocrine system involves general principles of endocrine signalling, major divisions, hormones of central and peripheral glands, and effects of over- or under-secretion.
Endocrine System Principles
- Specialized ductless glands and neurosecretory cells are scattered throughout the body and form this system
- Ductless glands release secretions into bloodstream or interstitial fluid directly
- Examples of ductless glands include the pituitary, thyroid, adrenal, pancreatic, pineal, parathyroid glands, and gonads (testes/ovaries)
- Neurosecretory cells are neurons and produce hormones, link the nervous and endocrine systems, and allow neural signals to regulate hormones
- Glands and cells secrete hormones, biologically active chemical messengers, into the blood
- Hormones are carried in the bloodstream to interact with distant target cells
- Interaction leads to cell response relating to metabolism, growth, or reproduction
Endocrine System Function
- One of the body's two major regulatory systems
- It regulates, integrates, coordinates, and controls important cellular, organ, and body functions
- These functions include cellular metabolism, water and electrolyte balance, growth and development, adaptation to stress, and control of circulatory and digestive systems
Hormone Classification
- Amines and amino acid derivatives are hydrophilic, like NA, AD, DA, melatonin, T3, and T4
- Polypeptides, proteins, and glycoproteins are hydrophilic, like TRH, ADH, GH, FSH, and insulin
- Steroids are lipophilic and derived from cholesterol, such as cortisol, testosterone, estradiol, and progesterone
Hydrophilic vs Lipophilic
- Hydrophilic hormones dissolve in blood and are free/unbound
- Lipophilic hormones, e.g., MT3, MT4, steroid hormones, nitric oxide (NO), are bound
Hormones Synthesis
- Vesicle-mediated pathway: synthesized in rough ER and packaged in secretory vesicles for polypeptide/protein hormones
- Non-vesicle-mediated pathway: synthesized in smooth ER and directly released for steroid hormones
Transport of Hormones
- Peptide hormones and amines are hydrophilic, dissolve in blood, and are free/unbound
- Steroid and thyroid hormones are carrier protein-bound
- Specialized plasma protein, usually bound to "globulin"
Hormone Secretion
- Secretion occurs in a pulsatile or cyclical manner, following diurnal or circadian rhythms
- Negative feedback control is achieved through end-product inhibition
Hormone Signaling
- Hormones affect target cells by interacting with specific receptors
- Target cell receptors link to specific effector systems in the cell
- Two main types of hormone receptors: cell surface receptors and intracellular or nuclear receptors
- Cell surface receptors include receptor-ion channels, G-protein coupled receptors, and tyrosine kinase-linked receptors
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