Ch 45 pt 1 Flashcards
Chemical Signaling by hormones
Endocrine system
Endo
within
Crine
secrete
What is the Nervous system?
Network of specialized cells-neurons- that transmit signals along dedicated pathways
Animals use ___ to communicate in diverse ways
Chemical signals
Where do endocrine cells secrete hormones into?
Extracellular fluids
What system picks up the hormones
Circulatory system
What are Local Regulators?
Molecules that act over short distances reaching target cells by diffusion
What happens in Paracrine signaling?
Target cells lie near the secreting cells
What happens in Autocrine signaling?
Target cell is also the secreting cell
Para
Along side
Auto
Self
What are Prostaglandins?
Local Regulators that mediate signaling in paracrine and autocrine signaling
Function in the immune system and blood clotting
What is Synaptic Signaling?
Neurons form specialized junctions with target cells called synapses
What are Neurotransmitters?
At synapses, secreted molecules that diffuse short distances and bind to receptors on target cells
What are neurohormones? (2)
1) Secreted by neurosecretory cells
2) diffuse from nerve endings into the bloodstream
Neuroendocrine signaling
Neurosecretory cells secrete neurohormones that diffuse from nerve endings into bloodstream
How do some animals species communicate
Pheromones, chemicals that are released into the environment
Pheromones uses (4)
1) Marking trails to food
2) Defining territories
3) Warning of predators
4) Attracting potential mates
Local Regulators such as Prostaglandins are modified _______
fatty acids
What are the 3 classes of local regulators?
1) prostaglandins
2) polypeptides
3) gases
traits of Nitric Oxide (2)
1) Gas that function as both a local regulator and neurotransmitter
2) When O2 in blood falls, NO activates enzyme that results in vasodilation
Hormones 3 major classes
1) Polypeptides (water soluble)
2) Steroids (lipid soluble)
3) Amines (water soluble)
characteristics of Water soluble hormones (3)
1) Secreted by exocytosis
2) Travel freely in the bloodstream
3) Bind to cell surface receptors
Lipid Soluble Hormones (4)
1) Diffuse across cell membranes
2) Travel in bloodstream bound to transport proteins
3) Diffuse through membrane of target cells
4) Bind to receptors in cytoplasm or nucleus of target cells
What does Signal Transduction lead to?
Leads to responses in cytoskeleton, enzyme activation, or change in gene expression
Usual response to a lipid-soluble hormone
Change in gene expression
What happens when a steroid hormone binds to its cytosolic receptor
The receptor complex forms that will move into the nucleus where it acts as a transcriptional regulator of specific target genes
Explain how Estradiol works
1) Binds to cytoplasmic receptor in liver cells of female birds and frogs
2) Activates transcription of genes needed to produce egg yolk
explain response pathway for water-soluble hormones (3)
1) hormone binds to a receptor on the target cell
2) signal transduction pathway
3) activated protein stimulates response
explain response pathway for lipid-soluble hormones (3)
1) steroid hormone binds to the cytosolic receptor
2) complex moves to the nucleus
3) the complex acts as a transcriptional regulator
