Unit 1: The Endocrine System Flashcards
Directly affect target cells
Immediate
Short-lived
Nervous System
Not close direct contact target cells
Bloodstream
Seconds,hours,or days
Longer-lasting
Endocrine system
Paracrine
Autocrine
Endocrine Glands
Three Chemical Signals
Chemicals secreted by cells to extracellular space
Nearby but different types of cells
Paracrine
Chemicals secreted by cells to interstitial fluid
Same cell or cell type
Autocrine
Diverse group throughout body
Regulate other cell types
Produce and secrete hormones
Endocrine Glands
Regulate other cell types by producing and secreting hormones
Endocrine Glands (organs)
Anterior pituitary gland Thyroid gland Parathyroid gland Adrenal cortices Endocrine pancreas Thymus
Primary Organs
Heart Kidneys Small intestines Testes Ovaries Hypothalamus(brain) Pineal gland (brain) Adrenal medulla (core adrenal gland)
Secondary organs
Chemical messengers secreted endocrine glands regulate functions other cells
Hormones
Cause widespread effects throughout body
Travel free inbound chemicals in blood or bound chemicals attached plasma protein carriers
Continue circulate bloodstream until taken up by target cell
Amount of a certain hormone in blood at given moment depends how fast and how much hormone is produced
Four Features Hormones
Hormones able affect particular cells called target cells
Receptor Location largely depends on chemical structure of hormones itself
Interactions of Hormones
Can not readily cross plasma membrane generally interact receptors found embedded target cells plasma membrane
*loves water
Hydrophilic Hormones
Able to cross through plasma membrane generally interact receptors found in cytosol or nucleus receptors
Hydrophobic Hormones
Target cells produce and display a greater number of receptors in response temporary increase hormone level in blood
Up-regulation
Target cells decrease number receptors displayed in response prolonged exposure high level hormone in blood
Down-regulation
Amino-acid Hormones
Steroid hormones
Two types chemical hormones
One or more amino acids
Hydrophilic
Bind to plasma membrane
Amino-acid Hormones
Derived from cholesterol
Hydrophobic
Bind cytosol or nucleus
Steroid hormones
Stimulating secretion from endocrine or exocrine cell
Activating or inhibiting enzymes
Stimulating/inhibiting mitosis/meiosis
Opening/closing ion channels cells plasma membrane potential
Activating or inhibiting transcription genes code for RNA/proteins
Effects Hormone Actions
Hormonal
Humoral
Neural
Three Types Stimuli
Some endocrine cells increase or decrease secretion response to secretion of other hormones
Hormonal Stimuli
Many endocrine cells respond to concentration of certain ion or molecule in blood or extracellular fluid
Humoral Stimuli
Some endocrine cells respond to signals from nervous system
Neural Stimuli
Stimulus: regulates from normal range
Receptor: picks up stimulus
Control Center: increase or decreases secretion of a particular hormone
Effector/Response: regulates back to normal
Negative Feedback Loops In Hormone Production
