Lecture 2 Flashcards
(31 cards)
What are the 3 central endocrine glands?
Hypothalamus
Pituitary
Pineal
What is responsible for the secretion of melatonin?
Pineal Gland
Is hypothalamus protected by the blood brain barrier?
NO
Where is the hypothalamus located?
Base of brain, between the brainstem and the cerebellum
What controls the release of hormones from the pituitary gland?
Hypothalamus
What are the 2 links through which the hypothalamus controls the pituitary gland?
Neurohypophysis - a direct neural link to the posterior pituitary
Adenohypophysis - a vascular link to the anterior pituitary
What are the posterior pituitary hormones?
Oxytocin
ADH
What is the primary function of ADH/vasopressin?
Produce more concentrated urine (antidiuretic)
Incrase blood pressure (vasopressin)
- the former will help achieve the latter
Where is the ADH receptor found?
Kidney cells
What occurs when ADH binds to receptors on specialized kidney cells?
Signals for vesicles containing aquaporins to bind to tubular membrane.
This allows the distal part of the tubular nephron to become permeable
Now water from the hypotonic filtate (urine) can be reabsorbed back into the blood stream
Other than an antidiuretic, what else can ADH cause to happen?
Mild contracions of smooth muscels in arterioles (vasopressor)
What is the primary stimulus of ADH release?
An increase in plasma osmolarity
When plasma is dilute, ADH release is inhibited. Why does this make physiologic sense?
No need to and dont want to absorb more water
What is diabetes insipidus?
Deficiency of ADH
What would be the difference between “central” and “nephrogenic” diabetes insipidus?
Central - deficiency of ADH
Nephrogenic - Kidney not responding to ADH
What are the clinical signs of diabetes insipidus?
Dehydrated
Peeing alot - polyuria
Animal will compensate by drinking a lot - polydipsia
How would you diagnose diabetes insipidus?
Quatnitfy urine
- Would have a very low specific gravity
- Dilute
What is the treatment for diabetes insipidus?
ADH treatment
- administered by IV or
- Eye or nasal drops
What is a synthetic ADH drug?
Desmopressin
General function of Oxytocin?
Stimulate contraction of specific smooth muscles
Effect of Oxytocin on uterus?
Expels fetus during parturition
What signals for the release of oxytocin during parturition?
Oxytocin release from posterior pituitary is stimulated by signals from afferent nerves in cervix which detect pressure from fetus
Effect of oxytocin in males?
Oxytocin may stimulate smooth muscles durring ejaculation
Effect of oxytocin on mammary glands?
milk-let-down
- stimulated by suckling baby
