How does oxytocin affect lactation?
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It promotes milk ejection during breastfeeding.
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How does oxytocin affect lactation?
It promotes milk ejection during breastfeeding.
Why is the hormone called Prolactin?
Because it helps estrogen and progesterone in their actions before milk secretion.
What role does oxytocin play in lactation?
It aids in milk ejection by the breasts.
What is the mechanism by which a baby obtains milk during breastfeeding?
By suckling, which triggers the release of milk due to oxytocin.
What is the pathway for light signals to the pineal gland?
From the eyes to the suprachiasmal nucleus of the hypothalamus and then to the pineal gland.
What is the primary function of the pituitary gland?
To regulate various hormonal functions in the body.
What must occur for milk to flow from the nipple into the mouth of the nursing infant?
Oxytocin secretion from the posterior pituitary must take place.
What important roles has the pineal gland been claimed to play?
In the control of sexual activities and reproduction.
What type of molecule is Growth Hormone (GH)?
It is a polypeptide.
How is Growth Hormone secreted?
In a pulsatile pattern.
What happens to the duration of labor in hypophysectomized animals?
It is prolonged, indicating a possible effect of oxytocin during delivery.
Do Growth Hormone (GH) effects occur directly on bones and peripheral tissues?
No, most effects are mediated by IGFs rather than direct effects of GH.
Which anterior pituitary hormone plays a major role in the regulation of a nonendocrine target gland?
C) Prolactin.
How does oxytocin facilitate breastfeeding?
It causes milk to be expressed from the alveoli into the ducts of the breast.
How do light signals affect the pineal gland?
Light signals pass from the eyes to the suprachiasmal nucleus of the hypothalamus and then to the pineal gland, activating its secretion.
What is the primary mediator of growth effects from Growth Hormone (GH)?
IGF-1 and other IGFs.
What is one metabolic function of Growth Hormone (GH)?
Increased rate of protein synthesis in most cells of the body.
What are the two main parts of the pituitary gland?
The anterior pituitary and the posterior pituitary.
What is the primary function of the hypothalamus?
To regulate various bodily functions and maintain homeostasis.
What triggers the release of vasopressin?
Increased plasma osmolality or decreased blood volume.
What happens to prolactin levels during milk ejection?
Prolactin levels must remain elevated, not fall, for milk production.
Can children with IGF deficiency have normal levels of another hormone?
Yes, they may have normal or elevated secretion of GH (Growth Hormone).
What happens to prolactin levels in the mother's blood as pregnancy progresses?
They rise steadily until birth.
What hormone does the pineal gland secrete?
Melatonin.
What are serum GH concentrations usually like at any moment in time?
They are usually low.
What condition has the 55-year-old man developed due to lung carcinoma?
Syndrome of inappropriate antidiuretic hormone secretion.
What type of cells does GH stimulate growth in independently of IGFs?
Chondrocytes of cartilage.
What triggers the increased secretion of oxytocin in pregnant animals?
Stimulation of the cervix elicits nervous signals to the hypothalamus.
How quickly does milk begin to flow after suckling starts?
In less than a minute.
How does GH affect fatty acids in the body?
Increased mobilization of fatty acids from adipose tissue and increased free fatty acids in the blood.
What hormone is produced by corticotropes?
Adrenocorticotropic hormone (ACTH).
How do growth hormones affect protein synthesis?
They promote protein synthesis in tissues.
What is the common belief about the pineal gland among many physiologists?
That it is a nonfunctional remnant.
What is the duration of action of growth hormone?
Short duration of action.
What is Laron Syndrome?
A rare genetic disorder characterized by insensitivity to growth hormone.
What is the role of suckling in infant development?
It provides nutrition and promotes bonding between mother and infant.
What role does vasopressin play in the kidneys?
It increases water reabsorption in the kidneys.
How does GH production change after adolescence?
Overall production decreases and continues at a lower rate during adult life.
Is Laron Syndrome associated with any other health issues?
Yes, it can be associated with increased risk of metabolic disorders.
What hormones are secreted by the anterior pituitary?
Growth hormone, prolactin, adrenocorticotropic hormone, thyroid-stimulating hormone, and others.
What is the expected effect on plasma osmolality in this syndrome?
Increased plasma osmolality.
What is the effect of GH on glucose utilization?
Decreased rate of glucose utilization throughout the body.
Name a hormone secreted by the anterior pituitary that stimulates growth.
Growth Hormone (GH).
What gland secretes prolactin during pregnancy?
The anterior pituitary gland.
What is the role of the pineal gland?
It is involved in the secretion of hormones activated by light signals.
What effect does oxytocin have on the pregnant uterus?
It causes contraction.
What is the mechanism called that facilitates the release of milk?
Milk letdown or milk ejection.
What hormone is responsible for the contraction of myoepithelial cells during milk ejection?
Oxytocin.
How does Laron Syndrome affect growth?
Individuals do not respond to growth hormone, leading to reduced growth.
What physiological response is expected in this condition?
Inappropriately low urine osmolality (relative to plasma osmolality).
What are IGFs?
Insulin-like Growth Factors.
What hormone is secreted by somatotropes?
Human growth hormone (hGH).
What is necessary for the baby to effectively suckle milk?
The baby's mouth must create a strong negative pressure over the nipple.
What symptom related to thirst might be expected in this condition?
Increased thirst.
What is the primary hormone whose secretion is affected by various factors?
Prolactin.
Which nuclei are responsible for the increased secretion of oxytocin during breastfeeding?
Paraventricular nuclei.
What is the role of oxytocin during breastfeeding?
It helps in milk ejection.
What role does melatonin play in the body?
It helps regulate circadian rhythms and sleep patterns.
To which family do GH receptors belong?
The cytokine family of receptors.
What is suckling?
The act of an infant feeding at the breast.
What is the primary action of vasopressin (AVP)?
To regulate water balance in the body.
How does vasopressin affect blood pressure?
It increases blood pressure by promoting vasoconstriction.
What is the role of melatonin in relation to the anterior pituitary gland?
It decreases gonadotropic hormone secretion.
What is the primary function of the pituitary gland?
To secrete hormones that regulate various bodily functions.
What is the effect of vasopressin on blood volume?
It increases blood volume by retaining water.
What is the main function of Growth Hormone in adult life?
Mainly metabolic.
What would NOT be expected in a patient with inappropriate ADH secretion?
Decreased secretion of ADH from the pituitary gland.
What hormones are secreted by the posterior pituitary?
Vasopressin (ADH) and oxytocin.
How does the hypothalamus communicate with the pituitary gland?
Through releasing and inhibiting hormones.
Which hormone is secreted by thyrotropes?
Thyroid-stimulating hormone (TSH).
What role do growth hormones play in fat metabolism?
They stimulate the breakdown of fats for energy.
How do growth hormones influence glucose metabolism?
They increase blood glucose levels by reducing glucose uptake in tissues.
How does light exposure affect the pineal gland?
Light exposure inhibits melatonin production, while darkness stimulates it.
What is the normal plasma prolactin concentration in men?
Approximately 5 ng/mL.
What triggers the release of Vasopressin?
Increased blood osmolarity or decreased blood volume.
What hormone regulates the menstrual cycle and ovulation?
Luteinizing Hormone (LH).
What is the effect of Growth Hormone (GH) on carbohydrates?
GH conserves carbohydrates.
What condition do children with IGF deficiency experience?
They fail to grow normally.
What hormone is primarily stimulated by suckling?
Prolactin.
How does suckling affect oxytocin release?
It stimulates the release of oxytocin, which helps with milk ejection.
What causes the difference in action duration between growth hormone and IGF-1?
Difference in protein binding.
What is the primary effect of oxytocin?
Stimulates uterine contractions during labor.
How does melatonin reach the anterior pituitary gland?
By way of the blood or through the fluid of the third ventricle.
What are the two main parts of the pituitary gland?
The anterior pituitary and the posterior pituitary.
What is the primary function of hypophysiotropic hormones?
To stimulate or inhibit the release of anterior pituitary hormones.
What role does the pituitary gland play in the endocrine system?
It acts as the master gland, controlling other endocrine glands.
How does the hypothalamus interact with the pituitary gland?
It releases hormones that control the secretion of pituitary hormones.
What nutrients do the hormones support for milk formation?
Amino acids, fatty acids, glucose, and calcium.
What role does insulin play in milk secretion?
It helps provide glucose necessary for milk formation.
From which textbook is the information about factors affecting prolactin and GH secretion adapted?
Ganong's textbook, 25th edition.
What hormone is responsible for stimulating growth and cell reproduction?
Growth Hormone (GH).
What secondary messenger is often involved in the action of growth hormones?
Insulin-like growth factor (IGF).
What hormone stimulates the adrenal cortex to release cortisol?
Adrenocorticotropic Hormone (ACTH).
Which hormone is responsible for stimulating the production of sperm?
Follicle-Stimulating Hormone (FSH).
What are the effects of oxytocin?
Oxytocin stimulates uterine contractions during childbirth and milk ejection during breastfeeding.
What are the main components of the GH receptor?
A large extracellular portion, a transmembrane domain, and a large intracellular cytoplasmic portion.
When does the concentration of prolactin in the mother's blood begin to rise?
From the fifth week of pregnancy.
What is the duration of action of IGF-1?
Prolonged action.
What causes Laron Syndrome?
Mutations in the growth hormone receptor gene.
What are the main symptoms of Laron Syndrome?
Short stature, obesity, and facial features resembling those of a child.
When does the amount of oxytocin in the plasma increase?
During labor, especially in the last stage.
Where are myoepithelial cells located in relation to the mammary glands?
They lie outside of and form a latticework surrounding the alveoli.
What is the anterior pituitary responsible for?
Secreting hormones that regulate growth, metabolism, and reproduction.
In what context is oxytocin often used in medical practice?
To induce or augment labor.
Which hormones are most important for milk secretion?
Growth hormone, cortisol, parathyroid hormone, and insulin.
What is the primary function of the pineal gland?
To produce melatonin, which regulates sleep-wake cycles.
What hormones are produced by the hypothalamus?
Releasing hormones like TRH, CRH, and GnRH.
What hormone secreted by the anterior pituitary is responsible for stimulating adrenal cortex activity?
Adrenocorticotropic Hormone (ACTH).
What type of factors are discussed in relation to prolactin secretion?
Factors affecting secretion.
What is neurophysin's relationship with oxytocin and ADH?
Neurophysin is a carrier protein for both oxytocin and ADH, but its secretion decreases during breastfeeding.
What is the primary function of growth hormone?
To stimulate growth and cell reproduction.
What effect does Growth Hormone (GH) have on body protein?
GH enhances body protein.
What is involved in the synthesis and secretion of posterior pituitary hormones?
The synthesis, processing, storage, and secretion of hormones like vasopressin and oxytocin occur in the hypothalamus and are released from the posterior pituitary.
What are hypophysiotropic hormones?
Hormones that regulate the secretion of hormones from the anterior pituitary gland.
What role do myoepithelial cells play in milk flow?
Myoepithelial cells must contract, not relax, to help expel milk.
What role does oxytocin play in social bonding?
It is involved in promoting social interactions and bonding.
What is the primary function of prolactin?
To stimulate the secretion of milk.
How does the pituitary gland interact with the hypothalamus?
The hypothalamus releases hormones that stimulate or inhibit the secretion of pituitary hormones.
What is the role of the posterior pituitary?
To store and release hormones produced by the hypothalamus, such as vasopressin and oxytocin.
What hormonal response is expected in a breastfeeding woman during suckling?
Increased secretion of oxytocin from the paraventricular nuclei.
What hormone is secreted by lactotropes?
Prolactin (PRL).
What are the two main parts of the pituitary gland?
The anterior pituitary and the posterior pituitary.
What is the role of Luteinizing Hormone (LH) secreted by the anterior pituitary?
To regulate ovulation and testosterone production.
What hormone is involved in childbirth and lactation?
Oxytocin.
What are the cell types present in the anterior pituitary?
The anterior pituitary contains several cell types, including somatotrophs, lactotrophs, corticotrophs, thyrotrophs, and gonadotrophs.
What is the relationship between growth hormone and muscle mass?
Growth hormone promotes an increase in muscle mass.
How does the structure of the pituitary gland relate to its function?
The pituitary gland's structure, with anterior and posterior lobes, allows it to produce and release various hormones that regulate bodily functions.
What other substances are secreted by the pineal gland besides melatonin?
Several similar substances.
Which gland do hypophysiotropic hormones primarily act upon?
The anterior pituitary gland.
What is the primary function of hormones secreted from the anterior pituitary?
To regulate various physiological processes in the body.
What is the relationship between the hypothalamus and the autonomic nervous system?
The hypothalamus regulates autonomic functions such as temperature and hunger.
Where is the pineal gland located?
In the brain, near the center, between the two hemispheres.
What is the significance of the hypothalamic-pituitary axis?
It coordinates the endocrine system's response to stress and other stimuli.
Which hormone from the anterior pituitary promotes milk production?
Prolactin (PRL).
What role does Oxytocin play in the body?
It is involved in childbirth and lactation.
Which hormone stimulates milk production in mammals?
Prolactin.
How does growth hormone influence carbohydrate metabolism?
It increases blood glucose levels by promoting gluconeogenesis in the liver.
What is the mechanism of action of growth hormones?
Growth hormones act by binding to specific receptors on target cells, leading to growth and metabolic effects.
What is the primary function of growth hormones?
To stimulate growth and cell reproduction.
What is the significance of the actions of hypophysiotropic hormones?
They play a crucial role in regulating various physiological processes by controlling anterior pituitary hormone secretion.
What energy source does GH promote for use in the body?
Increased use of fatty acids for energy.
Which hormone's secretion is mentioned alongside prolactin in the context of controlling factors?
Growth Hormone (GH).
What are the two main hormones secreted by the posterior pituitary?
Vasopressin (ADH) and Oxytocin.
What is the expected change in ADH levels during breastfeeding?
Increased secretion of ADH may occur, but oxytocin is more directly involved.
What hormone secreted by the anterior pituitary is involved in the menstrual cycle?
Follicle-Stimulating Hormone (FSH).
How does growth hormone affect protein metabolism?
It promotes protein synthesis and inhibits protein breakdown.
What is the effect of growth hormone on bone growth?
It stimulates the growth of bones and cartilage.
What are hypophysiotropic hormones?
Hypophysiotropic hormones are hormones that regulate the secretion of anterior pituitary hormones.
What hormones do gonadotropes produce?
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
What hormone is primarily secreted by the pineal gland?
Melatonin.
What is the effect of growth hormones on bone growth?
They stimulate the growth of bone and cartilage.
What is the mechanism through which growth hormones exert their effects?
By binding to specific receptors on target cells.
How are posterior pituitary hormones synthesized?
They are synthesized in the hypothalamus and stored in the posterior pituitary.
What role does growth hormone play in fat metabolism?
It stimulates the breakdown of fats and reduces the uptake of glucose by adipose tissue.
What hormones are secreted by the pineal gland?
Melatonin is the primary hormone secreted by the pineal gland.
What physiological stimuli affect prolactin secretion?
Physiological stimuli include pregnancy, breastfeeding, and stress.
Which hormone from the anterior pituitary stimulates the thyroid gland?
Thyroid-Stimulating Hormone (TSH).
How does cortisol contribute to milk production?
It supports the secretion of necessary nutrients for milk formation.
What is the primary function of Vasopressin?
To regulate water balance in the body.
Which hormone regulates water balance in the body?
Vasopressin (Antidiuretic Hormone, ADH).
What stimulates the release of Oxytocin?
Stretching of the cervix during labor and suckling during breastfeeding.
How are the numbers of cell types in the anterior pituitary controlled?
Their numbers are controlled in response to physiological demands.
What are the effects of vasopressin?
Vasopressin regulates water retention in the kidneys and increases blood pressure.
What is the normal plasma prolactin concentration in women?
Approximately 8 ng/mL.
Which hormone stimulates the thyroid gland?
Thyroid-Stimulating Hormone (TSH).
How does Growth Hormone (GH) affect fat stores?
GH decreases fat stores.
What physiological factors control prolactin secretion?
Prolactin secretion is controlled by factors such as dopamine inhibition and estrogen stimulation.
