10. Endocrine System 6 Flashcards
What is the main mineralcorticoid responsible for sodium and potassium levels?
Aldosterone
What factors affect how much aldosterone is being secreted?
- increased potassium ion concentration in the extracellular fluid greatly increased aldosterone secretion
- increased levels of angiotensin II greatly increases aldosterone secretion
- increased sodium ion concentration in the extracellular
fluid slightly decreases aldosterone secretion - ACTH needed for aldosterone to be secreted but does not affect rate of secretion
What are the effects of aldosterone?
- Increases absorption of sodium and secretion
of potassium by renal tubular epithelial cells - Same effect on sweat glands and salivary
glands
Explain aldosterone escape. Why is there a return to normal salt and water secretion within a few days of high aldosterone levels?
When aldosterone levels are high, more sodium is reabsorbed into the bloodstream. Because water follows sodium, this leads to increased extracellular fluid volume (the fluid outside of cells) and increased blood pressure.
Describe role of atrial natriuetic hormone
- Inhibits renin release
- inhibits aldosterone biosynthesis in the adrenal
cortex - vasodilator
What hormone is secreted by the pineal gland?
melatonin
What is the principal action of the hormones from the thymus gland?
Promote maturation of T cells
What is the tissue that composes the transient endocrine system?
placental tissue
- Name six hormones that are released by the placenta (not all occur in all species) and the function of each.
Progesterone: Keeps uterus ready for pregnancy.
Estrogen: Grows uterus and prepares for birth.
eCG/hCG: Maintain corpus luteum for progesterone.
Chorionic Somatomammotropin: Supports fetal growth and milk gland prep.
Prolactin: Prepares for milk production.
Relaxin: Softens cervix for delivery.
Describe the blood flow through the heart. Which parts are deoxygenated and oxygenated?
Left = oxygenated
Right = deoxygenated