Chapter 16- The Endocrine System Flashcards
Paracrine signals
Consists of a chemical secreted by cells into the extracellular fluid to affect nearby but different types of cells
Autocrine signals
A chemical secreted by cells into the interstital fluid elicits effects from the same cell or cell type
Endocrine signals
The hormone is secreted into the blood and travels to the affects into blood to affect distant tissues
Hormones
They interact with their target cell and influence the cell’s functions in order to maintain fluid, electrolyte, an acid- base homeostasis, promotes growth, regulates metabolic function and more
What are the primary endocrine glands?
Anterior pituitary gland Thyroid gland Parathyroid gland Adrenal cortices Endocrine pancreas Thymus
What are the secondary endocrine glands or neuroendocrine glands?
Testes and ovaries
Hypothalamus
Pineal gland
Adrenal medulla
Hydrophobic hormones
Are able to cross membranes due to the attraction between the hormone and membrane’s fatty acid tales (Lipid soluble)
Hydrophilic hormones
Cannot readily cross the phospholipid bilayer of plasma membrane to enter target cells because they are repelled by the fatty acid tails of phospholipid layer
Amino acid based hormones
Consist of one or more amino acid; generally hydrophilic and therefore bind to plasma membrane receptors
Steroid hormones
Cholesterol derivatives with a core of hydrocarbon rings; hydrophobic and can interact with either intracellular or plasma membrane receptors
Hormonal stimuli
When some endocrine glands increase or decrease their secretion in response to other hormones
- Hypothalamus releases stimulating or inhibiting hormones, which regulates the anterior pituitary
Humoral stimuli
Many endocrine cells respond to the concentration of certain ion or molecule in the blood or extracellular fluid such as glucose or calcium ions
Neural stimuli
Some cells respond to signals from the nervous system
Synergists
Hormones that can act on the same target cell to exert the same effect
Antagonists
Hormones that act on the same target that have opposite effects
What connects the hypothalamus and pituitary gland?
The infundibulum
Tropic hormone
Meaning they control secretion from other endocrine glands
Trophic hormones
Induces growth in its target cell
Where does the pituitary gland sit?
In the sella turcica of sphenoid bone
Does the posterior pituitary gland make its own hormones?
No, the hypothalamus makes them and the posterior pituitary stores and releases those hormones
What are the two hormones that the posterior pituitary gland releases?
Antidiuretic hormone (ADH) and oxytocin
What does the anti-diuretic hormone do?
It controls water balance within the body. The primary function is to increase the amount of water retained by the kidneys. It causes the insertion of aquaporins into plasma membranes of cells forming kidney tubules.
How does the hypothalamus monitor changes in solute concentration of the blood?
Osmoreceptors; stimulate ADH release from posterior pituitary
What is diabetes insipidus?
An abnormal lack of ADH secretion or activity, which results in extreme thirst and signs of dehydration because body is unable to conserve water
What is the function of oxytocin?
Oxytocin binds to the specialized cells in the mammary glands that stimulate their contraction resulting in milk ejection known as milk let down reflex— positive feedback loop within body; Also promotes emotional bonding in both sexes
