Growth Hormone and Its Effects
40 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which cell types, besides the liver, release somatomedin in response to growth hormone (GH)?

  • Adipocytes
  • Chondrocytes
  • Osteoblasts (correct)
  • Myocytes

What primarily differentiates Laron dwarfism from pituitary dwarfism?

  • Insufficient GH levels
  • Excess GH production
  • Nutritional deficiencies
  • GH receptor insensitivity (correct)

What is the primary characteristic of gigantism?

  • GH receptor malfunction
  • Excess GH production in adulthood
  • Excess GH production during childhood (correct)
  • Insufficient GH production in childhood

How much of the genetic growth potential is influenced by growth hormone (GH)?

<p>Approximately 30% (A)</p> Signup and view all the answers

What role does GH play during the fed state in terms of metabolic actions?

<p>It promotes protein synthesis. (D)</p> Signup and view all the answers

Which of the following describes acromegaly?

<p>GH overproduction in adulthood (A)</p> Signup and view all the answers

What metabolic action occurs during fasting due to GH?

<p>Mobilization of fat stores (B)</p> Signup and view all the answers

What is the effect of GH and IGF-1 during periods of favorable nutritional status?

<p>They promote anabolic growth. (D)</p> Signup and view all the answers

What is a primary physiological function of somatomedin?

<p>Mediating GH effects on growth (A)</p> Signup and view all the answers

Which condition arises from an excess of growth hormone after puberty?

<p>Acromegaly (A)</p> Signup and view all the answers

What primarily mediates the effects of growth hormone on stature?

<p>Release of somatomedin (D)</p> Signup and view all the answers

In what way does growth hormone influence adipose tissue?

<p>Promotes lipolysis to reduce fat stores (B)</p> Signup and view all the answers

Which tissue's response is enhanced by growth hormone through increased protein synthesis?

<p>Muscle tissue (C)</p> Signup and view all the answers

How does growth hormone contribute to linear growth of long bones?

<p>By enhancing chondrocyte proliferation at the growth plate (B)</p> Signup and view all the answers

What role does the liver play in the action of growth hormone?

<p>It releases somatomedin in response to growth hormone (C)</p> Signup and view all the answers

Which statement about the direct effects of growth hormone is true?

<p>It decreases glucose utilization in most tissues (D)</p> Signup and view all the answers

What is the result of growth hormone stimulating insulin-like growth factors (IGFs)?

<p>Enhanced differentiation and activity of chondrocytes (D)</p> Signup and view all the answers

Which of the following statements best describes the effects of growth hormone on bone metabolism?

<p>Stimulates osteoblast activity to promote bone formation (C)</p> Signup and view all the answers

Which of the following is NOT a function associated with growth hormone?

<p>Increasing insulin sensitivity (B)</p> Signup and view all the answers

What process in cartilage and bone is directly stimulated by growth hormone through IGFs?

<p>Proliferation of chondrocytes (D)</p> Signup and view all the answers

What hormone is primarily responsible for the synthesis and secretion of milk during lactation?

<p>Prolactin (A)</p> Signup and view all the answers

What effect does compromising the pituitary stalk have on prolactin secretion?

<p>Increases prolactin secretion (C)</p> Signup and view all the answers

What hormone from the hypothalamus stimulates the synthesis of growth hormone?

<p>Growth hormone-releasing hormone (GHRH) (B)</p> Signup and view all the answers

Which factor is crucial for establishing lactation post-delivery?

<p>Immediate initiation of nursing (B)</p> Signup and view all the answers

What type of feedback mechanism regulates prolactin secretion?

<p>Neuro-endocrine feedback loop (C)</p> Signup and view all the answers

What condition is associated with the absence of thyroid hormone in childhood?

<p>Cretinism (A)</p> Signup and view all the answers

What physiological action is primarily induced by oxytocin during lactation?

<p>Ejection of milk (D)</p> Signup and view all the answers

Which factor serves as the primary negative feedback regulator of growth hormone secretion?

<p>IGF-1 (D)</p> Signup and view all the answers

Which of the following is NOT a stimulatory factor for growth hormone secretion?

<p>Elevated blood pressure (D)</p> Signup and view all the answers

What is the impact of the hypothalamus on prolactin secretion under normal circumstances?

<p>It exerts an inhibitory influence on prolactin secretion (A)</p> Signup and view all the answers

How do growth hormone levels in children compare to those in adults?

<p>They are higher in children. (B)</p> Signup and view all the answers

When does the final arrangement of epithelial cells in the mammary gland occur?

<p>After the loss of pregnancy hormones with the delivery of the placenta (D)</p> Signup and view all the answers

What happens to growth hormone secretion as individuals age?

<p>It declines. (C)</p> Signup and view all the answers

What is critical for the maintenance of lactation?

<p>Consistent suckling (D)</p> Signup and view all the answers

What physiological response is activated by ghrelin regarding growth hormone?

<p>Stimulates secretion of growth hormone (A)</p> Signup and view all the answers

Which hormone with lactogenic properties is secreted by lactotropes?

<p>Prolactin (B)</p> Signup and view all the answers

Which phase is essential for continued milk production in a mature mammary gland?

<p>Stimulation by prolactin (B)</p> Signup and view all the answers

During which time period is the largest release of growth hormone typically observed?

<p>Early hours of sleep (D)</p> Signup and view all the answers

What role does thyroid hormone play in growth hormone synthesis?

<p>It is required for the formation of normal amounts of growth hormone. (B)</p> Signup and view all the answers

Why do adults continue to produce growth hormone throughout life?

<p>Due to its important role in metabolism. (C)</p> Signup and view all the answers

Flashcards

What stimulates growth hormone (GH) synthesis?

Growth Hormone-Releasing Hormone (GHRH) from the hypothalamus stimulates the production of growth hormone.

What is required for normal growth hormone levels?

The presence of thyroid hormone is necessary for normal levels of growth hormone.

What happens when thyroid hormone is absent?

Cretinism is a condition caused by the absence of thyroid hormone. It can lead to stunted growth.

What is the half-life of GH?

GH's half-life is short, meaning it's quickly broken down in the body.

Signup and view all the flashcards

How does IGF-1 regulate GH secretion?

IGF-1 (Insulin-like Growth Factor 1) is a primary inhibitor of GH secretion due to its longer half-life and binding proteins.

Signup and view all the flashcards

What is the role of Ghrelin in GH secretion?

Ghrelin, an incretin hormone released from the gut, stimulates GH secretion.

Signup and view all the flashcards

What are some stimulatory factors for GH?

Stress (physical or psychological), hypoglycemia (low blood sugar), amino acids, and trauma can all stimulate GH secretion.

Signup and view all the flashcards

How do GH levels differ between children and adults?

GH levels are higher in children compared to adults, with a peak during puberty.

Signup and view all the flashcards

What happens to GH levels with aging?

GH secretion declines as people age.

Signup and view all the flashcards

Do adults continue to produce GH?

Adults continue to produce GH, but at lower levels, primarily to maintain metabolism.

Signup and view all the flashcards

Growth Hormone (GH)

A hormone produced by the pituitary gland that plays a crucial role in growth and development.

Signup and view all the flashcards

Insulin-like Growth Factors (IGFs)

A group of proteins primarily produced by the liver that mediate the growth-promoting effects of GH.

Signup and view all the flashcards

How does GH promote linear growth?

GH stimulates the production of IGFs, which directly promote the growth and division of chondrocytes, leading to bone lengthening.

Signup and view all the flashcards

What is GH's effect on adipose tissue?

GH stimulates lipolysis, the breakdown of fat, increasing the availability of fatty acids for energy.

Signup and view all the flashcards

How does GH affect muscle growth?

GH enhances the production of proteins in muscles, leading to increased muscle mass and strength.

Signup and view all the flashcards

How does GH impact bone metabolism?

GH influences the activity of osteoblasts, the cells responsible for bone formation and remodeling.

Signup and view all the flashcards

What is the impact of GH on protein synthesis?

GH promotes protein synthesis in various tissues, contributing to overall growth and development.

Signup and view all the flashcards

How does GH affect glucose utilization?

GH decreases the body's use of glucose, promoting the utilization of fat as an energy source.

Signup and view all the flashcards

What is the liver's role in GH-mediated growth?

The liver is a key target for GH, releasing IGFs in response to its stimulation.

Signup and view all the flashcards

How are GH's effects on stature primarily mediated?

The effects of GH on stature are largely mediated by IGFs, which directly stimulate chondrocyte activity at the growth plates.

Signup and view all the flashcards

What other cell types release somatomedin?

Besides the liver, other cell types, such as those found in bone, can also release somatomedin in response to GH.

Signup and view all the flashcards

What is essential for adult stature?

Adult stature requires GH for proper growth.

Signup and view all the flashcards

What causes pituitary dwarfism?

Pituitary dwarfism in childhood is caused by a deficiency of growth hormone (GH).

Signup and view all the flashcards

What is Laron dwarfism?

Laron dwarfism is a condition where the body is unable to respond to GH due to a problem with the GH receptor, unlike pituitary dwarfism, which involves GH deficiency.

Signup and view all the flashcards

What is gigantism?

Gigantism is a condition characterized by excessive GH production during childhood, resulting in an exceptionally tall stature.

Signup and view all the flashcards

What is acromegaly?

Acromegaly is caused by overproduction of GH in adulthood, unlike gigantism, which occurs in childhood.

Signup and view all the flashcards

How does GH influence genetic growth potential?

GH plays a role in facilitating the genetic expression of growth potential.

Signup and view all the flashcards

What percentage of genetic growth potential is influenced by GH?

GH influences approximately ±30% of the genetic growth potential.

Signup and view all the flashcards

What are the effects of GH and IGF-1 in the fed state?

In the fed state, GH and IGF-1 promote anabolic growth by stimulating protein synthesis, cell growth, and tissue repair.

Signup and view all the flashcards

What are the effects of GH during fasting?

During fasting, GH mobilizes fat for energy while preserving glucose and protein levels.

Signup and view all the flashcards

What hormone do lactotropes secrete?

Prolactin (PRL) is a hormone secreted by lactotropes, cells found in the anterior pituitary gland.

Signup and view all the flashcards

Are lactotropes part of an endocrine axis?

Lactotrope cells are not part of a typical endocrine axis, meaning they don't directly respond to a tropic hormone from the hypothalamus.

Signup and view all the flashcards

How does the hypothalamus influence prolactin secretion?

The hypothalamus normally inhibits the release of prolactin.

Signup and view all the flashcards

What happens to prolactin secretion if the pituitary stalk is damaged?

When the pituitary stalk is disrupted, prolactin secretion increases significantly.

Signup and view all the flashcards

How is prolactin secretion regulated?

Prolactin secretion is regulated by a neuro-endocrine feedback loop, where the hypothalamus signals to the anterior pituitary, influencing prolactin release.

Signup and view all the flashcards

What hormone is responsible for milk ejection?

The ejection of milk from the mammary gland is controlled by oxytocin.

Signup and view all the flashcards

What is prolactin responsible for in lactation?

Prolactin is responsible for the production and secretion of milk by the mammary gland.

Signup and view all the flashcards

When does the final stage of mammary gland development occur?

The final stage of epithelial cell arrangement, involving tight junctions and the basement membrane, takes place after the delivery of the placenta and the subsequent decrease in pregnancy hormones.

Signup and view all the flashcards

When should nursing be initiated for lactation?

Nursing immediately after birth is critical to establishing lactation. It ensures high levels of prolactin to stimulate milk production.

Signup and view all the flashcards

What is required for milk production in the mature mammary gland?

The production of milk in the matured mammary gland depends on continuous stimulation by prolactin.

Signup and view all the flashcards

Study Notes

Physiology Lecture 22: Hypothalamus and Pituitary Hormones

  • Growth Hormone (GH) Synthesis Stimulation: Growth hormone (GH) synthesis is stimulated by growth hormone-releasing hormone (GHRH) from the hypothalamus.
  • Thyroid Hormone Requirement: Thyroid hormone is needed for normal amounts of GH formation.
  • Cretinism: Absent thyroid hormone results in cretinism, a condition characterized by short stature.
  • GH Half-life: GH has a specific half-life.

GH Secretion Regulation

  • IGF-1 and Ghrelin:
    • IGF-1 is a primary negative feedback regulator of GH secretion due to its longer half-life, aided by binding proteins.
    • Ghrelin, released from the gut, stimulates GH secretion, though its precise function isn't fully understood.
  • Stimulatory Factors: Stress, hypoglycemia, amino acids (like arginine), and traumatic or psychogenic stress stimulate GH secretion.

GH Secretion Patterns

  • Diurnal Rhythm: GH secretion follows a daily rhythm, with the largest release occurring during the early hours of sleep.
  • Childhood vs. Adulthood: GH levels are higher in children than in adults, peaking during puberty.
  • Aging and GH: GH secretion declines with aging.

Growth Hormone Actions

  • Promoting Bone Growth: GH promotes the growth of long bones, aiding in stature development.
  • Metabolic Actions: GH stimulates insulin-like growth factors (IGFs), enhances lean body mass by promoting protein synthesis and fat utilization.
  • Bone Metabolism: GH stimulates osteoblast activity, promoting bone formation and remodeling; encouraging long bone growth by stimulating chondrocyte proliferation at the epiphyseal plate

GH and Bone Growth

  • Liver's Role: The liver is a target organ for GH, releasing somatomedin in response to GH.
  • Somatomedin Effects: Somatomedin, released by the liver and other cells, mediates the effects of GH on stature.

Pituitary Dwarfism and Gigantism

  • Pituitary Dwarfism: Caused by a lack of GH during childhood.
  • Laron Dwarfism: Caused by a lack of response to GH due to GH receptor issues.
  • Gigantism: Caused by overproduction of GH during childhood, leading to a very tall stature approximately 8 feet.

Factors Affecting GH and Growth

  • Genetic Potential: GH influences about 20-30% of genetic growth potential, acting as a growth facilitator.
  • Metabolic States: In the fed state, GH promotes anabolic growth; in the fasting state, GH is catabolic, mobilizing energy.

Prolactin

  • Secretion and regulation: Secreted by lactotrophs in the anterior pituitary; controlled by a neuroendocrine feedback loop; Hypothalamus normally exerts an inhibitory influence on prolactin secretion.

  • Mammary Development and Lactation: Prolactin plays a role in the growth, stimulation, and milk synthesis and secretion of the mammary gland during pregnancy and lactation;

  • Compromised Pituitary Stalk: Prolactin secretion rises if the pituitary stalk is damaged.

  • Oxytocin Role: Oxytocin is responsible for the ejection of milk from the mammary gland.

  • Mammary Gland Effects of Prolactin: Elevated levels of prolactin (e.g., prolactinomas) can cause reproductive problems.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Physiology Lecture 22 PDF

Description

This quiz explores the various effects of growth hormone (GH) on the body, including its role in growth, metabolism, and related conditions. Test your knowledge on somatomedin, dwarfism, gigantism, and acromegaly, along with influencing factors of GH on growth potential and adipose tissue. Understand the complexity of GH's actions during different physiological states.

More Like This

Growth Hormone Regulation Quiz
10 questions

Growth Hormone Regulation Quiz

InvaluableOstrich3488 avatar
InvaluableOstrich3488
Growth Hormone Functions and Effects
24 questions

Growth Hormone Functions and Effects

EncouragingTurkey avatar
EncouragingTurkey
Use Quizgecko on...
Browser
Open
Browser
Browser