Flashcards in Endocrine System Deck (75)
What is the Endocrine System?
glands, tissues, and cells that secrete hormones
What are 2 properties of the endocrine glands?
produce hormones and lack ducts
List the endocrine glands
pituitary glands, thyroid gland, parathyroid gland, adrenal lands and pineal gland
List non-endocrine glands
hypothalamus, pancreas, ovaries and testes, and placenta
State the differences between Nervous and Endocrine system
Nervous: neurotransmitter, local, responds quickly, and stops quickly
Endocrine: hormones, general and widespread, responds slowly, and persist after stimulus stops
What are the 2 types of hormones?
amino acid-based and steroids
Which type of hormones are synthesized from cholesterol?
List hormones that are steroids
testosterone, estrogen, aldosterone, cortisol, and progesterone
How do hormones alter activity of target cells?
opening or closing ion channels, stimulating protein synthesis, activating or deactivating enzymes, inducing secretions, and stimulating mitosis
How do water-soluble hormones interact with target cells?
cannot enter target cells, act on receptors in plasma membrane, and coupled by G proteins to intracellular second messengers
How do lipid-soluble hormones interact with target cells?
can enter target cells, and act on intracellular receptors that directly activate genes
What are the steps in the cAMP signaling?
1. Hormone binds receptor
2. Receptor activates G protein
3. G protein activates adenylate cyclase
4. Adenylate cyclase converts ATP to cAMP
5. cAMP activates protein kinases
What non-steroid hormones also uses this mechanism?
What are the steps of the intracellular receptors?
1. The steroid hormone diffuses through the plasma membrane and binds to an intracellular receptor
2. The receptor hormone complex enters the nucleus
3. The receptor-hormone complex binds a hormone response element
4. Binding initiates transcription to the gene to mRNA
5. The mRNA directs protein synthesis
What is up-regulation compared to down-regulation?
up-regulation increases the cell number of receptors which then becomes more sensitive to a while down-regulation reduces cell number of receptors which then becomes less sensitive to a hormone
What are the 3 ways that multiple hormones that act on same target?
permissiveness, synergism, and antagonism
Describe synergism. give an example
two or hormones act together to produce an effect that is greater then sum of their separate effects. EP and glucagon
Define permissiveness. Give an example
one hormone cannot exert its full effects without another hormone being present. Estrogen and progesterone
Define antagonism. Give an example
one hormone opposes action of another hormone. Insulin and glucagon
What are the three types of stimuli?
humoral, neural, and hormonal
How is hormone synthesis and secretion regulated?
by negative feedback
Which hormones respond to neural stimuli?
oxytocin, ADH, NE, and EP
Which hormones respond to humoral stimuli?
Calcitonin, PTH, insulin, and glucagon
Which hormones respond to hormonal stimuli?
ALL pituitary hormones, TH, testosterone, estrogen, and progesterone
What is another name for the pituitary gland?
What connects the hypothalamus to the posterior pituitary?
What is the pos. pituitary glands composed?
What is the ant. pituitary composed?
What runs through the infundibulum and formed by axons of neurons?