Neuroendocrinology Flashcards
(23 cards)
Name the 2 types of neurons found in the hypothalamus
Parvocellular neurons
Magnocellular neurons
Where do parvocellular neurons go to?
Anterior pituitary via hypophysial portal system (capillary bed in the hypothalamus)
Where do magnocellular neurons go?
Axons extend directly to the posterior pituitary
What are the 3 axis of the neuroendocrine system?
Stress axis
Metabolism axis
Reproduction axis
How does the hypothalamus control homeostasis?
Behaviour - conscious thought e.g. seeking warmer environment
Neuronal control through the ANS (unconscious)
Hormonal control through hormone release from the pituitary gland (unconscious)
What is different about the blood brain barrier at the pituitary gland?
It is more ‘leaky’ than in other areas of the brain, selectively allows stuff into it to monitor input signals
What are the 6 homeostatic functions controlled by the hypothalamus
Blood pressure and electrolyte composition - control of drinking and salt appetite and control of blood osmolality and vasomotor tone
Body temperature - metabolic thermoregulation and behaviours like seeking an appropriate environment
Energy metabolism - feeding, digestion, metabolic rate
Reproduction - hormonal control of mating, pregnancy and lactation
Stress response - adrenal stress hormones
Growth - growth hormone
Why is the hypothalamus being closely related to the amygdala important?
Implies there is a signalling pathway from pre-frontal cortex to amygdala to hypothalamus. May describe emotional behaviour in homeostasis
Which nucleus in the hypothalamus is responsible for stress, energy balance and BP?
Paraventricular nucleus
What does the paraventricular nucleus in the hypothalamus control?
Stress
Energy balance
Osmoregulation
Maternal control
BP
Which nucleus in the hypothalamus is a support centre for other functions in the hypothalamus
Supraoptic nucleus - supports osmoregulation and maternal control
What does the supraoptic nucleus in the hypothalamus do?
Supports osmoregulation and maternal control (paraventricular support)
What does the arcuate nucleus of the hypothalamus control?
Reproduction
Growth
Lactation
Which nucleus in the hypothalamus is responsible for reproduction, growth and lactation?
Arcuate nucleus
Where is the pituitary gland located?
Bony cavity at the base of the brain stem called the sella turcica
How is the pituitary gland connected to the hypothalamus?
Through the pituitary stalk
Describe 4 things about the anterior pituitary gland
Develops from pharyngeal epithelium
Contains glandular cells
Parvocellular neurons
Releasing/inhibiting factors via portal system
Describe 4 things about the posterior pituitary gland
Develops from neuronal tissues
Contains axon terminals
Magnocellular neurons
Hormones directly released from magnocellular neurons
What is the developmental origin of the anterior pituitary gland?
Pharyngeal epithelium
What is the developmental origin of the posterior pituitary gland?
Neuronal tissue - makes sense, it has axons from the hypothalamus, means it is an extension of it
What hormones are released from the anterior pituitary gland?
GH
TSH (metabolism axis)
ACTH (stress axis)
FSH + LH (reproduction axis)
Prolactin - milk production
What hormones are released from the posterior pituitary gland?
ADH
Oxytocin - milk letdown (linked with prolactin from anterior). Smooth muscle contractions during birth.
Describe the release of vasopressin as a result of low BP
- Reduction in BP is detected by high pressure baroreceptors in the aorta and low pressure baroreceptors in the atria
- Sensory innervation via CN IX and X take info to nucleus tractus solitaries (NTS) in the brainstem
- The NTS signals to the hypothalamus to release vasopressin precursor
- VP travels to the posterior pituitary gland, which increases release of vasopressin
- Vasopressin acts on V1 receptors on blood vessels to increase vasoconstriction, therefore increasing blood pressure
