22 Questions
What is the primary function of the hypothalamus?
To integrate signals from the environment and generate an appropriate neuroendocrine response
Which of the following is NOT a function of the hypothalamus?
Contracting and relaxing skeletal muscles
What type of cells in the neuroendocrine system can secrete the same chemical substance with the same effect?
Glandular cells and neuronal cells
What is the term for the connection between the brain and the classic endocrine units?
Paradigm of neuroendocrine interactions
Which hormone is released by the hypothalamus and stimulates the anterior pituitary gland to release ACTH?
CRH
What is the primary mode of transmission of signals between the hypothalamus and the pituitary gland?
Paracrine transmission
What type of neurons release neurohormones that influence hypophysis hormones and regulate classical endocrine glands?
Parvicellular Neurons
What is the function of CRH in the hypothalamus-pituitary system?
To stimulate the release of adrenocorticotropic hormone
Which neurotransmitter inhibits the release of prolactin from the lactotroph cells?
Dopamine
What is the origin of the posterior pituitary gland?
Neural origin
What is the effect of abnormal hypophysis secretion on peripheral target endocrine glands?
Abnormal function
What is the function of GHRH in the hypothalamus-pituitary system?
To stimulate the release of growth hormone
Which type of neurons release oxytocin and vasopressin into the bloodstream?
Magnocellular Neurons
What is the effect of hyposecretion of trophic hormones on peripheral target endocrine glands?
Hypofunction
What is the primary purpose of receptor imaging PET CT in the evaluation of pituitary tumors?
To reveal secretory activity of the tumor
Which of the following hormones is often associated with hypersecretion in pituitary tumors?
PRL
What is the sensitivity of receptor imaging PET CT in detecting pituitary tumors?
1 cm
What is the primary role of somatostatin receptors in pituitary tumors?
Inhibiting hormone secretion
What is the purpose of visual field evaluation in patients with pituitary tumors?
To evaluate the effect of the tumor on surrounding structures
What is the primary advantage of using the Humphrey technique in visual field evaluation?
It is more sensitive than the Goldmann machine
What is the significance of non-functional adenoma (NFA) in pituitary tumor evaluation?
It is a sign of exclusion of real hormonal hypersecretion
What is the primary role of dopamine receptors in pituitary tumors?
Inhibiting hormone secretion
Study Notes
Neuroendocrine System
- The neuroendocrine system is the connection between the brain and the classic endocrine units, where the CNS regulates the endocrine system and the endocrine system modulates the CNS.
- The same chemical substance can be secreted by neurons and endocrine cells, having the same chemical messenger effect.
Hypothalamus-Pituitary System
- The hypothalamus-pituitary system is a paradigm of neuroendocrine interactions.
- The hypothalamus coordinates physiological responses to maintain homeostasis, including food intake, energy expenditure, body weight, fluid intake, blood pressure, thirst, body temperature, and sleep cycle.
- The hypothalamus integrates signals from the environment and different brain regions, generating the appropriate neuroendocrine response.
Hypothalamic Neurohormones
- Hypothalamic neurohormones influence hypophysis hormones and regulate classical glands.
- Examples of hypothalamic neurohormones include CRH (corticotroph releasing hormone), TRH (thyrotroph releasing hormone), GnRH (gonadotroph releasing hormone), and GHRH (growth hormone releasing hormone).
Pituitary Gland
- The pituitary gland has an anterior lobe of ectodermal origin and a posterior lobe of neural origin.
- The pituitary gland has a specific distribution and is vulnerable to trauma, with somatotroph cells being posterolateral and vulnerable, corticotroph cells being anteromedial and resilient, and lactotrope cells being diffuse and very resilient.
- The effects of anterior pituitary hormones are mediated strictly through peripheral classic endocrine glands.
Evaluation and Diagnosis
- Morphofunctional evaluation can be done using receptor imaging (PET CT), such as dopamine receptor imaging and somatostatin receptor imaging.
- Functional evaluation is used to detect the presence of a tumor with secretory activity and to reveal distant metastasis.
- Hypersecretion screening is done for frequent tumors, such as prolactinoma and GH-secreting tumors.
- Visual field evaluation is used to detect effects on surrounding structures, such as stalk compression or deviation, optic chiasm compression, and cavernous sinus invasion.
Learn about the neuroendocrine system, including the hypothalamus, pituitary, and the connection between the brain and endocrine units. Understand how the CNS regulates the endocrine system and how it's modulated in return.
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