Anterior and Posterior Pituitary Hormones

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Questions and Answers

What is the primary function of growth hormone (GH)?

Promote growth by affecting protein formation and cell differentiation (correct)

Stimulate milk production in mammary glands

Regulate water balance in the body

Control the secretion of adrenocortical hormones

Which hormone is responsible for the regulation of water excretion?

Prolactin

Antidiuretic hormone (ADH) (correct)

Growth hormone

Oxytocin

What role does oxytocin (OT) play during childbirth?

Facilitates milk expression during suckling (correct)

Stimulates the mother’s appetite

Regulates the sleep cycle

Increases body temperature

Adrenocorticotropin (ACTH) primarily affects the metabolism of which substances?

Glucose, proteins, and fats Signup and view all the answers

Thyroid-stimulating hormone (TSH) controls the secretion of which hormones?

Thyroxine and triiodothyronine Signup and view all the answers

Which hormone is involved in both ovarian and testicular functions?

Follicle stimulating hormone (FSH) Signup and view all the answers

What is the anatomical significance of the anterior pituitary gland's vascularization?

It facilitates hormone transport from the hypothalamus to its sinuses Signup and view all the answers

Which two hormones released by the posterior pituitary are critical in different bodily functions?

Antidiuretic hormone (ADH) and oxytocin (OT) Signup and view all the answers

What is a significant physical effect of decreased growth hormone secretion in aging individuals?

Increased fat deposition Signup and view all the answers

Which of the following is NOT an undesirable effect of growth hormone therapy?

Increased protein deposition Signup and view all the answers

What can be a potential consequence of long-term growth hormone deficiency?

Decreased muscle strength Signup and view all the answers

What is one of the immediate benefits of growth hormone therapy in older adults?

Feeling of increased energy Signup and view all the answers

Why is recombinant growth hormone therapy not generally recommended for healthy elderly patients?

It may cause adverse effects Signup and view all the answers

What is the primary function of osteoblasts in bone tissue?

Depositing new bone Signup and view all the answers

How does growth hormone affect bone thickness?

It stimulates osteoblast activity Signup and view all the answers

What are somatomedins also known as?

Insulin-like growth factors Signup and view all the answers

What primarily regulates growth hormone secretion over the long term?

Nutritional status, especially protein levels Signup and view all the answers

Which condition is characterized by decreased secretion of all anterior pituitary hormones?

Panhypopituitarism Signup and view all the answers

Which type of tumor is commonly associated with pituitary gland compression and potential growth hormone abnormalities?

Craniopharyngioma Signup and view all the answers

What effect does nutritional deficiency have on growth hormone secretion?

It increases the rate of secretion Signup and view all the answers

Which of the following is a consequence of excessive growth hormone activity?

Bony protrusions over the eyes Signup and view all the answers

What is the main function of the posterior pituitary gland?

It stores and secretes hormones produced by the hypothalamus. Signup and view all the answers

Which hormone is primarily produced in the paraventricular nuclei?

Oxytocin Signup and view all the answers

What effect does Antidiuretic Hormone (ADH) have in the collecting ducts?

It increases the permeability of the ducts to water. Signup and view all the answers

During childbirth, how is oxytocin released from the posterior pituitary?

In response to signals from the hypothalamic neurons. Signup and view all the answers

What is the role of osmoreceptors in relation to ADH?

They monitor blood osmolarity. Signup and view all the answers

What is the process known as 'let-down' in breast feeding?

The ejection of milk stimulated by oxytocin. Signup and view all the answers

How do oxytocin receptors change during pregnancy?

They are newly synthesized and increase toward the end of pregnancy. Signup and view all the answers

Which statement accurately describes ADH in relation to urine concentration?

It concentrates urine by promoting water reabsorption. Signup and view all the answers

Which of the following is a result of adult panhypopituitarism?

Loss of sexual functions due to suppressed gonadotropic hormones Signup and view all the answers

What is one of the physiological characteristics of a child with dwarfism due to growth hormone deficiency?

They exhibit normal body proportion but slower development Signup and view all the answers

What is the main cause of acromegaly in adults?

Tumor in the pituitary gland Signup and view all the answers

Which of the following treatment options is effective for individuals with pure growth hormone deficiency?

Recombinant DNA-synthesized human growth hormone Signup and view all the answers

What physical change is NOT typically associated with acromegaly?

Growth of excess body hair Signup and view all the answers

In individuals with dwarfism, what might be true about the secretion of growth hormone?

It can be normal or high in some cases Signup and view all the answers

Which of the following symptoms is commonly experienced by adults with acromegaly?

Joint pain Signup and view all the answers

What happens to bone growth in adults with acromegaly after the epiphyses have fused?

Bones can become thicker Signup and view all the answers

Study Notes

Anterior Pituitary Hormones

Growth Hormone (GH): Promotes overall body growth by influencing protein creation, cell division, and differentiation.
Adrenocorticotropin (ACTH): Regulates the release of specific adrenal cortex hormones that control glucose, protein, and fat metabolism.
Thyroid-Stimulating Hormone (TSH): Controls the thyroid glands secretion of thyroxine and triiodothyronine, which regulate most cellular chemical reactions.
Prolactin: Stimulates mammary gland development and milk production.
Gonadotropic Hormones (GnRH): Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH) regulate growth and functions of ovaries and testes, including reproductive activities.

Posterior Pituitary Hormones

Antidiuretic Hormone (ADH) (Vasopressin): Controls water excretion in urine, regulating fluid concentration.
Oxytocin (OT): Facilitates milk ejection during breastfeeding and promotes childbirth.

Anterior Pituitary Structure

Highly vascular gland with extensive capillary sinuses.
Blood flow: Hypothalamus → Hypothalamic-Hypophysial Portal Vessels → Anterior Pituitary Sinuses.

Posterior Pituitary Structure

Extension of neurons from the hypothalamus' paraventricular and supraoptic nuclei.
Neuron cell bodies located in the hypothalamus, axons extend through the infundibulum to the posterior pituitary.
Posterior pituitary stores and releases hormones produced by the hypothalamus.

Neurohypophysis Hormones

Oxytocin:
- Polypeptide hormone formed in the paraventricular nuclei.
- Stimulates uterine contractions and cervical dilation.
- Receptors increase in the uterus during pregnancy, enhancing sensitivity to oxytocin's effects.
- Released throughout childbirth via positive feedback.
- Essential for milk ejection reflex (let-down) during breastfeeding.
Antidiuretic Hormone (ADH):
- Polypeptide hormone formed in the supraoptic nuclei.
- Osmoreceptors in the hypothalamus monitor blood osmolarity (solute concentration).
- ADH increases water permeability in collecting ducts and tubules, conserving water and producing concentrated urine.
- Absence of ADH makes collecting ducts impermeable to water.
- Aquaporins (water-permeable pores) in cell membranes facilitate water reabsorption.

Growth Hormone Effects

Stimulates osteoblasts (bone-forming cells), increasing bone thickness throughout life, particularly in membranous bones (e.g., jaw, skull).
Promotes the production of somatomedins (insulin-like growth factors) by the liver and other tissues.
Somatomedins enhance bone growth, similar to insulin's effects on growth.

Growth Hormone Regulation

Primarily regulated by nutritional state, especially protein nutrition.
Deficiency or increased tissue protein need (e.g., after exercise) stimulates growth hormone secretion.
Growth hormone promotes new protein synthesis and conserves existing proteins.

Abnormalities of Growth Hormone Secretion

Panhypopituitarism:
- Deficient secretion of all anterior pituitary hormones.
- Can be congenital or develop at any age, often caused by pituitary tumors or blood vessel thrombosis.
- Symptoms include hypothyroidism, decreased glucocorticoid production, and suppressed gonadotropic hormones.
Dwarfism:
- Anterior pituitary deficiency during childhood.
- Proportional growth but at a significantly slower rate.
- May involve only growth hormone deficiency, allowing sexual maturity.
- Some dwarfism result from a hereditary inability to produce somatomedin C.
Acromegaly:
- Excess growth hormone after adolescence, causing bone thickening and soft tissue growth.
- Caused by pituitary adenomas (acidophilic tumors).
- Symptoms include enlarged hands and feet, altered face shape, headaches, joint pain, vision changes, and increased skin tags.

Role of Decreased Growth Hormone in Aging

Reduced growth hormone accelerates aging features, including skin wrinkling, organ function decline, and muscle mass loss.
Contributing factors include decreased protein deposition and increased fat deposition.

Growth Hormone Therapy

Recombinant growth hormone treatment is available.
Effective for treating pure growth hormone deficiency in dwarfs.
In older individuals, beneficial effects include increased protein deposition, reduced fat deposits, and increased energy.
Undesirable side effects include insulin resistance, edema, carpal tunnel syndrome, and joint pain.
Growth hormone therapy is generally not recommended for healthy elderly individuals with normal endocrine function.

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Description

This quiz covers the major hormones produced by the anterior and posterior pituitary glands, including their roles in regulating growth, metabolism, and reproductive functions. Test your knowledge on Growth Hormone, ACTH, TSH, and more. Understand the significance of these hormones in human physiology.