Posterior Pituitary And Hypothalamus Flashcards
The saddle-shaped protective pocket for the pituitary gland
Sella turcica
What bone of the skull features the sella turcica and pituitary gland?
Sphenoid bone
What are the 2 anatomically and functionally distinct lobes of the pituitary ?
Posterior and anterior
The ____ pituitary is composed of nervous tissue
Posterior
The ____ pituitary comprises glandular epithelial tissue (endocrine)
Anterior
Does the anterior pituitary produce or store hormones?
Produce
Does the posterior pituitary store or produce hormones?
Store
What are the 2 hormones of the posterior lobe of the pituitary ?
Oxytocin and vasopressin
Secretion of hormones of the posterior pituitary is independent controlled from neurons within the _________ and ______ nuclei of the hypothalamus
Paraventrcular and supraoptic
Name 2 roles of oxytocin
Childbirth and breastfeeding
Explain the role of oxytocin in child birth
Sensory signals from cervix (stretch) = oxytocin is released= uterine muscles contract to deliver fetus
Explain the role of oxytocin in breastfeeding
Infant suckling induces sensory signals= oxytocin is released = mammary gland muscles contract to release milk
What feedback mechanism is operating with oxytocin and childbirth/ breastfeeding
Positive
_____- attachment of couples and nurturing parental behaviour
Pair bonding
How is oxytocin released in men or non-pregnant women?
Bonding and sex
What part of the brain is the site of interaction between nervous and endocrine systems
Hypothalamus
What hormone is part of the feedback loop that controls body fluid volume and concentration ?
Vasopressin
What are the 2 target cells of vasopressin ?
Kidney
Vascular smooth muscle
How does vasopressin target kidney cells ?
Reduce urine and conserve water
How does vasopressin target vascular smooth muscles ?
Cause vasoconstriction (blood pressure)
How does anti-diuretic occur?
Increase permeability of water up collecting ducts= More water reabsorbed in kidneys = less urine produced
_______= high osmolarity of extracellular fluids
Hyperosmolarity
_____- low blood volume
Hypovolemia
High osmolarity of extracellular fluids (hyperosmolarity), low blood volume (hypovolemia) and low arterial blood pressure stimulate what feeling ?
Thirst
The secretion of what hormone stimulates hyperosmolarity, hypovolemia and low arterial blood pressure ?
Vasopressin
Does vasopressin concentration rise or lower in response to increased ECF osmolarity
Rise
Does vasopressin concentration rise or lower in response to reduced blood volume ?
Rise
What neurons detect changes in extracellular fluid (ECF) osmolarity ?
Hypothalamic osmoreceptor
Does an increase or decrease in hyperosmolarity cause cells to shrink due to osmotic forces ?
Increase
What happens to vasopressin (ADH) secretion when osmoreceptor neurons shrink ?
Increases
High extracellular osmolarity leads to ________ release
Vasopressin
Osmoreceptor neurons low outside of the _______
Blood brain barrier
Baroreeptors, also known as _______detect amount of “stretch” and signal SON and PVN neurons
Sensory nerve endings
Blood volume sensors for control of vasopressin secretion are located in ____ pressure vessels
Low
Does decreased stretch of vessels cause an increase or decrease of ADH secretion to recover fluid volume ?
Increase
SON and PVN in the hypothalamus stand for what ?
Supraoptic nuclei and paraventricular nuclei
What happens to kidney/water after an increase in ADH secretion ?
Kidney collecting tubes increase water reabsorption
What happens to blood volume after an increase in water reabsorption in the kidney
Decreased
Alcohol inhibits ____ secretion
ADH
What happens to blood volume and ECF osmolarity when dehydration occurs ?
Decrease and increase
Alcohol inhibits ADH secretion which results in ____
Dehydration
Dehydration stimulates ____ secretion as alcohol is cleared
ADH
Morning thirst is stimulated through _____ thirst centre neurons connected to osmoreceptors
Hypothalamic
