Unit 08: Endocrine System Flashcards
What does the endocrine system do?
Chemical signaling by hormones for length term slow processes, like growth.
What are endocrine glands?
Groups of endocrine cells in ductless organs that secrete hormones into surrounding fluid.
What are hormones?
Chemical signals secreted into bloodstream, target cells have receptors specific to the hormones.
Describe endocrine signaling.
Endocrine cells secrete signal into bloodstream which then travel to target cells (long distance).
Describe local regulators.
Cells secreting molecules into space, affecting nearby target cells (short distance).
What are the two types of local regulation, describe them briefly.
Paracrine - affecting different cell type
Autocrine - affecting same cell/type
What is synaptic signaling?
Neurotransmitters secreted by neurons (presynaptic cell), diffuse to nearby post synaptic cell.
What cell types can be post synaptic?
Endocrine, muscle, nervous
What is neuroendocrine signaling?
Neurosecretory cell secretes neurohormones into circulatory system, which then travels to faraway target cell.
What are the 3 types of hormones?
Polypeptides, steroids, and amines.
Describe the water soluble hormone endocrine pathway.
Stored, then secreted into blood where it dissolves, then travels to target cell where it binds to cell-surface receptors.
Then, initiates signal transduction pathway, where the response can either be gene regulation or a cytoplasmic function.
Describe the lipid soluble hormone endocrine pathway.
Diffuse across cell membrane into blood where it travels bound to transport proteins. Then, binds to cell receptors in cytoplasm/nucleus.
Response? Gene regulation.
Which hormone types are water-soluble?
Polypeptides, amines
Which hormone types are lipid-soluble?
Steroids, amines
What is the function of the hypothalamus?
To integrate nervous and endocrine system (sends signals to start endocrine signaling in pituitary)
Also regulates production of hormones in anterior pituitary.
What is the function of the posterior pituitary?
To secrete the neurohormones produced by hypothalamus (as it is an extension of the hypothalamus)
What is the function of the anterior pituitary?
Produces/secretes tropic and non tropic hormones.
What is the difference between tropic and non tropic hormones?
Tropic - regulates function of endocrine cells/glands
Non-tropic - does not regulate function of endocrine cells and glands.
How does epinephrine effect the liver?
Beta receptors receive signal, promotes breakdown of glycogen into glucose.
How does epinephrine effect skeletal muscle?
Beta receptors recieve signal, muscle relaxes, allowing vasodilation, blood flow to skeletal muscle increases.
How does epinephrine effect small intestine?
Alpha receptors receive signal, muscle contracts, causing vasoconstriction, therefore blood flow to small intestine decreases.
What are some factors that may impact how a hormone affects a cell?
Different signal transduction pathways, different receptors.
Describe a simple endocrine pathway.
1 gland-signal-target-response.
Gland receives stimulus->
releases hormone into circulatory system ->
travels until target cell is reached ->
signal transduction ->
response ->
stimulus will increase/decrease ->
pathway will either continue or stop
What is an example of a simple endocrine pathway?
Raising pH in small intestine if too acidic. Negative feedback loop.
Describe a simple neuroendocrine pathway.
Sensory neuron receives stimulus ->
Neurohormone secreted into blood ->
Signal reaches target cell ->
Signal transduction ->
Response ->
Stimulus increases/decreases ->
Pathway either continues or stops
What is an example of a simple neuroendocrine pathway?
Milk release via suckling. Positive feedback loop.
What is a hormone cascade?
Series of tropic hormone (greater than 1 gland-signal-target-response)
What is the function of insulin?
To decrease blood glucose levels by storing glucose in liver and body cells as glycogen.
What is the function of glucagon?
To increase blood glucose levels by breaking down glucagon stored in the liver into glucose.
Describe what occurs when blood glucose levels are above set point.
Beta cells of pancreas release insulin into blood which enhances the storage of glucose as glycogen in body cells and in the liver.
Describe what occurs when blood glucose levels are below set point.
Alpha cells of pancreas release glucagon into blood which promotes breakdown of glycogen stored in the liver into glucose.
