Lecture 1 - Basics in Neuroendocrinology Flashcards
Outline the key features of the sympathetic nervous system
Responds to stimuli Stress Thoarcolumbar Ganglia close to the spinal cord Short pre-ganglionic Long post-ganglionig Post-ganglionic = NA
Outline the key features of the parasympathetic nervous system
Reaxation Craniosacral 12 cranial nerves Ganglia are far from the spinal cord Long pre-ganglionic Short post-ganglionic Post-ganglionic = ACh
What are the 12 cranial nerves?
Olfactory Nerve Optic Nerve Oculuomotor Trochear nerve Trigeminal nerve Abducins Facial Nerve Auditory Nerve glosopharyangeal nerve Vagus nerve Spatial Accessory Nerve Hypoglossal
Why is the vagus nerve important?
It detects what’s going on and reacts to this
What are the four main types of cardiovascular regulation?
Chronotropy (HR)
Dromotropy (Conduction Velocity)
Inotropy (Contractility)
Lusitropy (Relaxation)
Outline Chronotropy
It takes place in the SA node
The sympathetic NS increases HR
The Parasympathetic NS decreases HR
Outline Dromotropy
AV Node
The sympathetic NS increase conduction velocity by increasing the rate of calcium inlfux
The parasympathetic NS decreases conduction velocity
Outline Inotropy
Ventricles
The sympathetic nervous system increases contactiliyy by increasing calcium concentration
The parasympathetic NS has no significant effect
Outline Lusitropy
Ventricles
The sympathetic NS increases relaxation speed by stimulating the Ca pump
The parasympathetic NS has no significant effect
What is the Hypohphysial portal system?
The capillary system between the hypothalamus and pituitary gland
What are the hormones released by the hypothalamus to the pituitary?
Gonadotropin Releasing Hormone (GnRH) Cortisol Releasing Hormone (CRH) Thyrotropin Releasing Hormone (TRH) Growth Hormone Releasing Hormone (GHRH) Prolactin Inhibitory Factor (PIF)
What hormones are released from the anterior pituitary gland?
Follicle Stimulating Hormone/Lutenizing Hormone (FSH/LH) Adrenocorticotrophic hormone (ACTH) Thyroid Stimulating Hormone (TSH) Growth Hormone (GH) Prolactin
Which hormones are released from the posterior pituitary gland?
ADH
Oxytocin
What are the key characterisitics of BBB capillaries?
No fenestrated endothelium Tight junctions Few pinozytes Little transcellular transport Lots of mitochondria Astrocytes processes are present
What are the functions of the BBB?
A selective barrier between the blood and the brain
To guarantee optimal homeostasis in neuronal mileu
Protects against circulating neuroactive substancces e.g. amino acids
Outline some BBB associated pathologies
Tumours can cause opening of the BBB
Bacterial meningitis
HIV Demenetia
What are the circumventricular organs?
Are regions in the brain which have extensive vasculature and no BBB
What are the circumventricular organs?
Choroid Plexus Subfornical Organ (SFO) Area postrema Subcommissaral organ (SCO) Hypophyse (Pituitary) Eminenta mediana Organum Vascularism der Lamina Terminalis (OVLT)
Where does the CSF come from?
the choroid plexus and the ECF
What is Bulk Flow?
The action of ECF flowing inwards, and as it flows inbetween the cells it beccomes CSF
What is special about the sinus sagittalis superior?
It is where the blood and CSF meet
What are the layers of the meninges?
Pia Mater, Arachnoidea, Dura Mater
What are the functions of CSF?
Homeostasis
To remove potentially dangerous metabolites
Mechanical protection of the brain
What are the general functions of the hypothalamo-hypophysial system?
Intergration of all sensory inputs
COmplex regulatory control over: Behavioural responses, cardiovascular responses, thermoregulation, hormonal output , reproductive functions and immune functions
What are the nuclei in the hypothalamus?
Dorsomedial hypothalamic nucleus Periventricular nucleus Lateral tuberal nucleus Arcuate nucleus Ventromedial hypothalamic nucleus Supraoptic nucleus Media preoptic area Paraventricular nucleus Nucleus supraoplexus
What are the inputs to the hypothalamus?
Sensory info via monosynaptic projections
Multi-synpatic projections from limbic system and the cortex
Projections from circumventricular organs
Steroidal hormone feedback
How can the inputs to the hypothalamus be classified?
By neurotransmitter
What are the two parts of the hypthalamo-hypohysial system?
The Hypothalalomo-adenohypophysial system
The Hypothalamo-neurohypophysial system
Outline the hypothalamo-adenohypophysial system
Information travels by neurons from the hypothalamus to the portal blood where there is a direct link to the endothelial cell –> hormone release to the adenohypophysis
Outline the hypothalama-neurohypophysial system
Long neural projections all the way down the neurohypophysis
Which hormones are released in the hypothalamo-adenohypophysial system?
ACTH TSH STH LH/FSH Prolactin
What tissue is the adenohypophysis derived from?
the hypophyseal pouch in the mouth cavity consisting of ectodermal-epithelial tissue
What tissue is the neurohypophysis derived from?
From a neurohypophyseal bud coming down from the brain, composed of ectodermal-neural tissue
What are Ernst and Bert Scharrer famous for?
They founded neuroendocrinology with the neurosecretion hypothesis
What is the neurosecretion hypothesis?
Suggests that neurons store, synthesise and release hormones
What is Wolfgang Borgmann famous for?
He worked on the link between the hypothalamus and the hypophyse
Outline the stress response
Stressor –> Hypothalamus –> CRH –> Adenohypophysis –> ACth –> Adrenal GlAND –> Cortisol/Corticosteron –> Stressor
What are the inputs for the stress response?
Limbic system
Brainstem
Catecholinergic inputs
Noradrenergic inputs
A2 NA cell group, NTS
A1 NA cell group of the ventrolateral medulla
Locus coerulus
Cholinergic inputs from the caudal thalamus
Serotonergic inputs from the caudal thalamus
What is stress?
Complex, sterotypical response toa real/threatened disruption of the homeostasis and intergrity of somatic control systems. It is the non-specific response of the body to any demand
What is a stressor?
the external stimulus causing stress
What factors are the height and duration of the stress response dependent upon?
Intensity of stressors
Quality of stressors
Duration of stressors
What are the physiological mechanisms of the stress response?
Activation of the sympathetic NS causes increeased HR, blood pressure and breathing frequency, it also causes released of adrenaline from the adrenal glands.
Activation of the neuroendocrine systems. CRH neurons release ACTH causing glucocorticoids, cortisol to be released
What are the effects of the stress response?
Energetic support fro the fight or flight response Increased vigilance induction of anxiety regulation of stress related behaviour inhibition of anabolic processes inhibition of immune responses
