Neuroendocrine Systems Flashcards
Function of hypothalamic neurons?
Where do they specifically lead to
Secrete hormones into the blood vessels specifically leading to the pituitary gland
Hypothalamic-pituitary-adrenocortical axis
- General flow?
- Elevated glucocorticoids lead to ?
- Other function of ACTH?
- Hypothalamic neurons release CRH which stimulates ant pituitary to release ACTH into blood which stimulates adrenal cortex to synthesize/secrete glucocorticoids
- Promotes glycogenolysis and gluconeogenesis (catabolic hormone) - also exerts negative feedback on the axis
- Acts as a growth factor to induce adrenal hypertrophy
- What part of the skull is located near the pituitary gland?
- Where in the brain is the pituitary gland located?
- Where is the pineal gland located in the brain?
- Located with the sella turcica of the skull base (hypophyseal fossa)
- Attached to ventral surface of the hypothalamus
- Deep midline position on the brain surface; protruding from the posterior surface of the thalamus
Pituitary gland contains 2 main elements, what are they?
Axon terminals and endocrine cells
- Function of axon terminal of the neuroendocrine neurons of the pituitary gland
- Endocrine cells of the pituitary gland are regulated by ?
- Releasing hormones into the capillaries
2. Hormones released by neurons located in the hypothalamus
4 major parts of the brain
Cerebrum, cerebellum, brainstem, and spinal cord/roots
3 parts of the cerebrum?
Cerebrum/cerebral hemispheres, thalamus, and hypothalamus
3 parts of the brain stem in order from superior to inferior
Midbrain, pons, and medulla oblongata
3 parts of the anterior pituitary
2 parts of the posterior pituitary
Pars tuberalis, pars intermedia, and pars distalis
Infundibular stalk and pars nervosa
- What does the pars distalis contain?
2. What does pars nervosa contain?
- Endocrine cells regulated by hypothalamic hormones
2. Axon terminals of hypothalamic neurons
Locations of the pars tuberalis?
Surrounds infundibulum
Neurohypophyseal system:
- Some hypothalamic neurons send axon projections where?
- Here, axon terminals release what, where?
- What 2 hypothalamic hormones are released this way?
- Through the infundibulum to the posterior lobe (pars nervosa)
- Release peptide hormones into systemic circulation via hypophyseal veins
- Vasopressin (ADH) and oxytocin
- Where are oxytocin neurons located?
- Where are vasopressin neurons located?
- What are considered “nuclei” in the hypothalamus
- Paraventricular nuclei
- Supraoptic and paraventricular nuclei
- Clusters of neuron cell bodies
What happens to the following in HYPERtonic solutions:
- Neurons
- Mechanosensitive ion channels
- Action potentials
- ADH
~reverse for hypotonic
- Neurons shrink
- Open
- Action potentials start firing
- ADH secretion
Hypertonic solutions means __ plasma osmolarity
High
Central/neurogenic diabetes insipidus
- Deficiency in?
- Symptoms
- Treated by?
- Causes?
- ADH synthesis/release by supraoptic and paraventricular neurons
- Chronic thirst/polydipsia, polyurea/dilute urine, can be fatal is no access to water
- Hormone replacement
- Head trauma, neurosurgical complications, tumor/lesions
What is nephrogenic diabetes inspidius?
Insensitivity to ADH
Syndrome of inappropriate ADH
- What is it?
- Symptoms
- How is it managed
- Danger in treating it how?
- Causes?
- Excess ADH synthesis/release by supraoptic and paraventricular neurons
- Hyponatremia, range between fatigue and coma/seizures
- Restricted water intake, ADH antagonist
- Danger in rapidly “correcting” by giving hypertonic saline - can cause demyelination in pons (potentially fatal)
- Head trauma, variety of neurological disorders, NSAIDs
Neurons of the adenohypophyseal system project to the ___
What do they do here
Median eminence (ventral surface) and release peptide hormones into capillaries of the portal circulation which delivers these hormones to endocrine cells of the anterior pituitary
- Neurohypophyseal system projects into __ lobe, secretion into ___
- Adenohypophyseal system projects into __ and secretes into __ to __
- Neurohypophyseal system projects into posterior lobe, secretion into systemic veins
- Adenohypophyseal system projects into median eminence and secretes into portal veins to anterior pituitary cells
Posterior pituitary consists of, and not ?
Consists of capillaries and axon terminals; no endocrine secretory cells
Name 6 hormones made and released by the anterior pituitary
TSH, GH, LH, FSH, ACTH and prolactin
- Another name for growth hormone releasing hormone
- Another name for growth hormone inhibiting hormone
- What neurotransmitter acts as prolactin inhibiting hormone?
- Somatotropin
- Somatostatin
- Dopamine
Function cell type that releases the following hormones:
- ACTH
- FSH/LH
- TSH
- GH
- Prolactin
- Stem cells
- Corticotropes
- Gonadotropes
- Thyrotropes
- Somatotropes
- Lactotropes
- Folliculo-stellate cells
- Which hormones are basophilic (purple) (3)
2. Which hormones are acidophilic (pink/orange) (2)
- ACTH, FSH/LH, TSH
2. GH, prolactin
What are neurosecretory granules
Peptide hormones in the axon terminals to be secreted
Where are axon terminals positioned?
So release of granules is followed by
Close to or adjacent to endothelial cells
Transport of hormones across endothelial cells into blood
Lobes of the pituitary are derived from?
What are the two parts?
Ectoderm
Oral ectoderm and neuro ectoderm
- What part is derived from oral ectoderm
2. Neuro ectoderm?
- Pars distalis/anterior lobe
2. Pars nervosa
Why does the hypothalamus rarely experience infarct/ischemia?
Primary neurological problem in the hypothalamus?
It is highly vascularized
Tumor formation
Traumatic brain injury can sever?
Infundibulum which would disconnect the hypothalamus and pituitary
Two types of pituitary tumors?
These tumors grow and expand out of the __, compressing ?
Hypersecretory or non-secretory
Sella turcica, compressing cranial nerves or hypothalamus
Location of the pineal gland
What effect does light exposure have on the pineal gland
At a deep midline position on the brain surface
Light exposure inhibits pineal synthesis and secretion of melatonin (darkness= less inhibition of pineal and more melatonin)
How light inhibits pineal/melatonin:
- Light activates what kind of cells. What does these cells do when activated?
- SCN sends excitatory projections to __
- PVN sends excitatory projections to __
- These stimulate __ to do what?
- Retinal ganglion cells; send excitatory projections to a hypothalamic nucleus (suprachiasmatic nucleus)
- Another hypothalamic nucleus (paraventricular nucleus)
- Pre-ganglionic sympathetic neurons in T1-T2 spinal cord
- Post ganglionic sympathetic projections to pineal to inhibit melatonin secretion
What pools between the two tails of the pineal gland
CSF
