Types of Signaling
signaling type where the target cell is the secreting cell
autocrine signaling
What are the 3 major chemical classes
polypeptides, steroid, amines
In a simple endocrine pathway, endocrine cells respond to a stimulus by...
secreting a particular hormone
In a negative feedback loop...
the response reduces the initial stimulus
The posterior pituitary gland _____ and _______ hormones, while the anterior pituitary _____ and _______ hormones
posterior stores and secretes hormones made in hypothalamus
Anterior makes and releases hormones under regulation of the hypothalamus
In paracrine signaling, how does the local regulator reach the target cell
diffusion (short distance)
The water soluble hormones include which classes?
polypeptides and most amines
Hormones travel through the __________ to reach target cells
bloodstream
In a positive feedback loop...
reinforced stimulus to produce a greater response
In vertebrates, endocrine signaling is coordinated by the _______
hypothalamus
Neurons can communicate with target cells by using...
specialized junctions called synapses
The solubility of the steroid hormones could be described as... (what is the significance?)
lipid soluble (hydrophobic), they can diffuse across membranes.
In hormone signaling, signal transduction occurs where?
Within the target cell
What is the purpose of feedback regulation?
To control the activity of the stimulus based on the end product of the pathway
In invertebrates, the molting of larva is controlled by what neurohormone?
PTTH, which triggers ecdysteroid which triggers the molt and metamorphosis
Marking food trails, defining territory, warning of predators, and attracting potential mates
A water-soluble hormone usually triggers what type of cell responses (need 3 of 4)
Activation of enzyme, change in uptake/secretion of molecule, rearrangement of cytoskeleton, changes in transcription.
In a neuroendocrine pathway, what is the term for the hormone?
neurohormone
Give an example of negative feedback loop.
An increase in pH in the intestines caused by secretin shuts down further release of secretin.
Neurosecretory cells of the hypothalamus synthesize which two posterior pituitary hormones?
Antidiuretic hormone (ADH) which regulates physiology and behavior and oxytocin which regulated milk production in mammary glands.
Maintaining homeostasis, mediating response to stimuli, regulating growth and development, triggering changes leads to sexual maturity/reproduction
A change in gene expression is the most common cell response to what class of hormone? (how does the process work)
Lipid soluble (steroids and some amines). steroid hormone bonds to receptor in cytoplasm, a hormone receptor complex moves to nucleus and acts as transcriptional regulator of target genes.
How does a neuroendocrine pathway differ from a simple endocrine pathway.
A neurosecretory cell is stimulated by a sensory neuron.
Give an example of positive feedback loop.
Oxytocin causes the release of milk, which caused greater suckling, which stimulates more oxytocin to be released.
In a mammal, what happens when thyroid hormone in the blood drops too low?
the hypothalamus secretes thyrotropin-releasing hormone (TRH), causing the anterior pituitary to secrete thryoid-stimulating hormone (TSH). The TSH then stimulates release of thyroid hormone from the thyroid gland.