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27 Cards in this Set
- Front
- Back
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a hormone whose main purpose is to control the release of another hormone.
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releasing hormone
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a hormone whose main purpose is to inhibit the release of other hormones.
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inhibiting hormone
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hormones that have other endocrine glands as their target.
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tropic hormone
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What are hormones?
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chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body.
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What are two specific differences between the endocrine and nervous systems?
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The endocrine system secretes hormones that coordinate slower but longer-acting responses including reproduction, development, energy metabolism, growth, and behavior.
The nervous system conveys high-speed electrical signals along specialized cells called neurons; these signals regulate other cells. |
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What are the five different types of secreted signaling molecules?
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Hormones
Local regulators Neurotransmitters Neurohormones Pheromones |
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What is the difference between and endocrine gland and an exocrine gland?
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endocrine glands are ductless and secrete hormones directly into surrounding fluid.Exocrine glands have ducts and secrete substances onto body surfaces or into body cavities (for example, tear ducts, salivary glands)
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What is a local regulator?
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are chemical signals that travel over short distances by diffusion to reach their target cells.
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What are the two different classes of local regulators and how do they differ?
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Paracrine signaling – secreted molecules act on cells near the secreting cell.
Autocrine signaling – secreted molecules act on the secreting cell itself. |
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What is the difference between a neurotransmitter and a neurohormone? Give an example.
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neurotransmitters-molecuels that diffuse a short distance to bind receptors on target cells.
Neurotransmitters play a role in sensation, memory, cognition, and movement. Neurohormones are a class of hormones that originate from neurosecretory cells in the brain that secrete molecules that diffuse into the bloodstream. ADH (vasopressin) is one example. |
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What are pheromones? How might they be used?
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Pheromones are chemical signals that are released into the external environment with the purpose of communicating with other members of the same species.
Pheromones serve many functions including marking trails leading to food sources, warning of predators, and attracting potential mates |
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What are the three major classes of molecules that function as hormones? Which are water-soluble and which are lipid-soluble?
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Polypeptides (proteins and peptides)
Amines derived from amino acids Steroid hormones Water:polypeptide, amines Lipid: Steroid, Amines |
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What is the correlation between the solubility of a hormone and the location of its receptors?
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The solubility of a hormone correlates with the location of receptors inside or on the surface of target cells.
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In addition to receptor location, water-soluble and lipid-soluble hormones also exhibit additional differences in their response pathways. What are these differences?
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Water-soluble hormones are secreted by exocytosis, travel freely in the bloodstream, and bind to cell-surface receptors.
Lipid-soluble hormones diffuse across cell membranes, travel in the bloodstream bound to transport proteins, and diffuse through the membrane of target cells. |
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What is a signal transduction pathway?
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is a series of steps by which a signal on a cell’s surface is converted into a specific cellular response.
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Signaling by a hormone involves three key events. What are they?
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(1) Reception
(2) Signal transduction (3) Response |
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What is a G protein coupled receptor? Provide an example of a hormone that utilizes a G protein coupled receptor in its signal transduction pathway.
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activated by an external signal in the form of a ligand or other signal mediator.
The hormone Epinephrine |
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If someone said to you that a particular hormone utilizes a G protein coupled receptor in its transduction pathway, would they be talking about a water- or lipid-soluble hormone?
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Lipid soluble.
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Where is the receptor for a lipid-soluble hormone located? (hint: It can be found in either of two locations)
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What is the typical cellular response initiated by a lipid-soluble hormone?
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a change in gene expression.
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What is a transport protein and why do lipid-soluble proteins require them?
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Why can the same hormone have different effects on different body tissues?
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The same hormone may have different effects on target cells that have:
(1) Different receptors for the hormone (2) Different signal transduction pathways and/or effector proteins A hormone can also have different effects in different species. |
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Liver cells and the blood vessels of skeletal muscle cells have identical surface receptors for epinephrine, yet the response of these two cell types is dramatically different. Explain how this is possible.
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In the “Fight or Flight Response” the release of epinephrine from the adrenal medulla causes skeletal muscle blood vessels to dilate while simultaneously constricting blood vessels of the intestine. Explain how this is possible.
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List the three types of local regulators discussed in class and explain their function
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Cytokines as we saw earlier play a role in the immune response. Nitric oxide is a gasa that acts as both a neurotransmitter and a local regulator. NO activates enzymes that relaxes smooth muscle cells resulting in vasodilation. In human males NO enables sexual function by increasing blood flow into the penis producing an erection. Highly reactive and potentially toxic NO triggers changes within a few seconds and then breaks down. Viagra (sidenafil citrate) works by interfering with this breakdown.
Prostaglandins are modified fatty acids. Produced by many cell types and have various activities. In the immune system they promote fever and inflammation. They intensify the sensation of pain. Aspirin and ibuprofen interfere with prostaglandin synthesis. Prostaglandins also help regulate the aggregation of platelets. Also help maintain protective lining in the stomach. |
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Hormonal pathways generally operate on the principle of _________________, in which the response to the stimulus leads to a reduction in the stimulus.
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negative feedback.
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Some homeostatic control systems rely on sets of simple hormone pathways with coordinated activities. One common arrangement is a pair of pathways each counter-balancing the other. Give an example. What is the advantage of this arrangement?
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