PHYSIOLOGY - Neuroendocrinology Flashcards
What is the neuroendocrine system?
Interaction between the nervous system and the endocrine system
What are the two main anatomical components of the neuroendocrine system?
Hypothalamus
Pituitary gland
What are the three functions of the hypothalamus within the neuroendocrine system?
- Exerts autonomic nervous system control on hormone release by the adrenal medulla
- Produces and releases regulatory and inhibitory hormones
- Produces antidiuretic hormone (ADH) and oxytocin
How is the hypothalamus a heterogeneous organ?
The hypothalamus is a heterogenous organ as it is made up of many different nuclei (clusters of neuronal cell bodies)
Which type of neurones produce oxytocin and antidiuretic hormone (ADH)?
Magnocellular neurones
In which nucleus in the hypothalamus is oxytocin produced?
Paraventricular nucleus
In which nucleus in the hypothalamus is antidiuretic hormone (ADH) produced?
Supraoptic nucleus
Which five regulatory/inhibitory hormones are produced by the hypothalamus?
Gonadotrophin releasing hormone (GnRH)
Corticotrophin releasing hormone (CRH)
Thyrotrophin releasing hormone (TRH)
Dopamine
Somatostatin
What is the sella turcica?
Depression in the sphenoid bone that contains the pituitary gland
What are the two structural components of the pituitary gland?
Anterior pituitary gland
Posterior pituitary gland
What is the embryological origin of the anterior pituitary gland?
Ectoderm
What is the embryological origin of the posterior pituitary gland?
Neuroectoderm
What is the section of tissue residing between the anterior and posterior pituitary gland?
Pars intermedia
Which hormone is secreted by the pars intermedia?
Melanocyte stimulating hormone
What is the function of the anterior pituitary gland?
Production and release of tropic hormones and direct action hormones
What is the difference between tropic hormones and direct acting hormones?
Tropic hormones stimulate other endocrine glands to facilitate the realise of another hormone whereas direct acting hormones act directly on the target organ
What regulates the release of tropic and direct acting hormones from the anterior pituitary gland?
Hypothalamus releases regulatory and inhibitory hormones into the hypophyseal portal system which transports these hormones to the anterior pituitary gland where they will regulate the release of tropic and direct acting hormones
What are the two main types of chromophil secretary cells found in the anterior pituitary gland?
Acidophils
Basophils
What are the two subdivisions of acidophils?
Somatotrophs
Mammotrophs
Which hormone is produced by somatotrophs in the anterior pituitary gland?
Growth hormone
Which hormone is produced by mammotrophs in the anterior pituitary gland?
Prolactin
What are the three subdivisions of basophils?
Gonadotrophs
Thyrotrophs
Corticotrophs
Which hormones are produced by gonadotrophs in the anterior pituitary gland?
Follicular stimulating hormone (FSH)
Leutinising hormone (LH)
Which hormone is produced by thyrotrophs in the anterior pituitary gland?
Thyroid stimulating hormone (TSH)
Which hormone is produced by corticotrophs in the anterior pituitary gland?
Adrenocorticotropic hormone (ACTH)
What are chromophobes?
Chromophils which have released their hormones
What is the function of the posterior pituitary gland?
Storage and release of oxytocin and antidiuretic hormone (ADH) that has been produced by the hypothalamus
What is the main histological component of the posterior pituitary gland?
Non-myelinated axons
What are the supporting cells within the posterior pituitary gland?
Pituicytes
What are herring bodies?
Herring bodies are dilated axon terminals in the posterior pituitary gland that store and release oxytocin and antidiuretic hormone (ADH)
What does the pineal gland secrete?
Melatonin
What are the two main cell types seen in the pineal gland?
Pinealocytes
Astrocytes
What is pineal sand?
Concentric layers of calcium and magnesium phosphate seen in ageing pineal glands
Describe the histological appearance of the thyroid gland
The thyroid gland has a fibrous outer capsule from which fine septa extend to seperate the thyroid gland into lobules. These lobules contain thyroid follicles filled with colloid (thyroid hormone precursor) and surrounded by a single layer of cuboidal epithelium
