Week 9 Flashcards
What are some of the Major Endocrine glands?
What are the 3 modes of endocrine secretion?
What is the role of Negative feedback in the hypothalamic-pituitary-thyroid axis?
What is a Hormone?
Chemical messengers that induce a response in the target tissue/organ
What are some hormone examples of Steroids?
What are some hormone examples of Peptides?
What are some Hormone examples of Proteins?
What are some Hormone examples of Glycoproteins?
What are some Hormone examples of Amino acid derivatives?
What 3 factors control Hormone release from Endocrine glands?
- Humoral
- Neural
- Hormonal
What may the patterns of hormone secretion throughout the day look like?
A - Diurnal variation
B - Constant value
C - As needed
How do we test for Endocrine disorders?
How do we access Pituitary in surgery?
Through Sphenoid air sinus (top of nasal cavity)
What are some Neurohormones controlling the release of ant. pituitary hormones?
What are some Neurohormones released from the post. pituitary?
What hormones are produced in the Paraventricular nuc. in the hypothalamus?
- CRH
- TRH
- OXT
- VP / ADH
What hormones are produced in the Supraorbital nuc. in the hypothalamus?
- OXT
- VP
What hormones are produced in the Preoptic nuc. in the hypothalamus?
GnRH
What hormones are produced in the Arcuate nuc. in the hypothalamus?
- GnRH
- PIH (dopamine)
What hormones are produced in the Periventricular nuc. in the hypothalamus?
- PIH (dopamine)
- SS
Describe Diabetes Insipidus
Very thirsty
Need to pee often
Describe Oxytocin’s production, binding, and release
Describe the hypothalamic control of milk production and ejection
What are some of the simplified cascades of Hormones from the ant. pituitary?
What are the 3 parts of the Adenohypophysis?
- pars Distalis
- pars Tuberalis
- pars Intermedia
What are the 2 parts of the Neurohypophysis?
- pars Nervosa
- Pituitary Stalk
Describe the Embryonic development of the pituitary gland
What may happen if there is residual tissue of pharyngeal hypophysis that becomes neoplastic?
Craniopharyngioma
(hormone secreting tumour)
What are the different cell types of the Ant. Pituitary?
Label this cross section of the Ant. Pituitary
Describe the indepth table of Ant. Pituitary hormones
Describe the mechanism controlling Growth Hormone release
Describe feedback inhibition of Growth Hormone release
What are the levels of Growth hormones throughout the day?
Pulsitile and Diurnal
What are the Physiologial actions of Growth Hormone?
(Diagram)
What are the Physiological actions of Growth Hormone?
(text)
What are some Pathologies associated with Growth Hormone deficiency?
What are some Pathologies associated with Growth Hormone excess?
What are some physical signs of Acromegaly?
How do hormones get from small bodied neurons to ant. pituitary?
Release hormones into primary capillary plexuses or median eminence which then carries them to ant. pituitary
How do hormones get from large bodied neurons to post. pituitary?
They dirrectly innervate the post. pituitary
What are the Hypothalamic neurohormones’:
- Structure
- Hypothalamic nuclei of origin
- Effect on ant. pituitary
In what structure are Oxytocin and Vasopressin synthesised and processed?
Secretory Vesicle
What is the function of signal peptides in pre-pro Vasopressin / Oxytocin?
Dirrects pre-pro Vasopressin / Oxytocin into the ER, where the signal protein is then cleaved off
What 2 other structures are present in pre-pro Vasopressin?
Neurophysin II
Copeptin
What other structure is present in pre-pro Oxytocin?
Neurophysin I
What can Copeptin be used to measure?
AVP levels
(produced in same proportion, longer half life)
What is the function of Neurophysin I / II?
To protect Oxytocin / Vasopressin as they move through circulation to the target tissue before releasing
Achieves this by binding Oxytocin / Vasopressin
What may cause the release of AVP from the SON & PVN?
- Increase Blood Osmolality (osmoreceptors in lamina terminalis)
- Decrease Blood Vol (carotid sinus, aortic arch, left atrium)
- RAAS (angiotensin II)
How does cell differentiation occur in the Ant. Pituitary gland during development?
Via the Dorsal gradient (fibroblast growth factor 8 FGF8)
and the Ventral gradient (bone morphogenic protein 2 BMP2)
These oppose each other.
The Ventral diencephalon expresses FGF8
Rathke’s pouch expresses BMP2
Depending where the progenitor cells lie on these gradients, they will differentiate into a specific cell type
What are the 5 cell types of the Ant. Pituitary from Superior to Inferior?
- Corico tropes
- Somato tropes
- Lacto tropes
- Thyro tropes
- Gonado tropes
What controls Thyroid secretion?
Thyroid Stimulating Hormone (TSH)
secreted by ant. pituitary
What is the function of Cuboidal epithelial cells?
Secretion of colloid into follicles of thyroid gland
Main component of colloid is thyroglobulin, which contains the thyroid hormones.
What must first happen to thyroid gland secretions before they can function in the body?
What cells produce Calcitonin?
C cells
What % of metabolically active hormones secreted by the thyroid gland are T4 & 3?
93% & 7%
What happens to almost all of T4 eventually?
Converted into T3
What’s the difference between T3 & T4?
T3 x4 as potent as T4 but is present in the blood in much lower quantities and persists for a shorter time
What is needed to form thyroxine and how much of it is needed?
Iodine
50mg/year
What is the link between T3 & 4 and metabolic rate?
What does the TG do to Iodide (not iodine)?
Sequestered, XS excreted by kidney
Describe Iodide trapping in TG
Describe the synthesis and secretion of Thyroglobulin
Synthesised and secreted into follicles by ER and Glogi apparatus
Describe Thyroglobulin and its function
Large Glycoprotein molecule