Exam I CH 17 Flashcards
- Understand the endocrine system’s contribution to homeostasis
Regulation
- Metabolism
- Food intake
- Hunger Saftey
- Ion and water balance
- Blood glucose and nutrient levels
- Reproduction
- Tissue growth and development
- IMmune function
- Blood cell production
- Compare the various types of chemical messengers
Chemical Messengers- Are produced by a specific collection of cells or by a gland. They specialize in SECRETION- the controlled release of chemicals from a cell.
- AUTOCRINE- Chemical messenger stimulates the cell that originally secreted it.
- Ex: Those secreted by white blood cells during an
infection.
- Ex: Those secreted by white blood cells during an
-PARACRINE- Chemical messengers act locally on neighboring cells. They are secreted by one type into the extracellular fluid and affect surrounding cells.
-Ex: Histamine is released by certain white blood cells
during allergic reactions. It stimulates vasodilation
in nearby blood cells.
-NEUROTRANSMITTERS- Secreted by neurons that activate an adjacent cell, whether itis another neuron, a muscle cell, or a glandular cell. They are secreted into a synaptic cleft, rather than into the bloodstream. They travel through the general circulation to their target cells.
- Know the characteristics of the endocrine system including glands, hormones, and target tissues
The endocrine system is made of endocrine glands and specialized endocrine cells located throughout the body.
Endocrine glands secrete very small amounts of chemical messengers called HORMONES into the bloodstream, rather than a duct.
Hormones circulate through the bloodstream to specific sites called TARGET TISSUE, or EFFECTORS.
At their target tissues, hormones stimulate a specific response.
4a. Compare and contrast the nervous system and the endocrine system. Similarities
- Both the NS and ES use the Hypothalamus
Nervous function is when the hypothalamus detects changes in body temperature; it sends action potentials to either the sweat glands or skeletal muscle, depending on whether the body is too hot or cold.
Endocrine function is when hypothalamus sends hormones tot he pituitary gland that regulates the secretion of hormones to the pituitary.
- NS use certain hormones as neurotransmitters, whereas ES may use these molecules as hormones. When a neuron secretes epinephrine into the synaptic cleft, it is a neurotransmitter. In contrast, when cells of the adrenal gland secrete epinephrine into the bloodstream, it is a hormone.
- Some neurons secrete hormones. The nueron’s chemical messenger enters the bloodstream, where it functions as a hormone. Called neuropeptides, or neurohormones. Ex: Oxytocin
4b. Compare and contrast the nervous system and the endocrine system. Differences
- Mode of Transport
- ES secretes hormones, transported in the bloodstream
- NS secretes neurotransmitters, directly to a target cell - Speed of Response
- NS (milliseconds) responds faster than ES (seconds) - Duration of Response
- NS activates its target quickly and only as long as action potentials are sent to the target. The targets cells’ response is terminated shortly after action potentials cease
- ES remain active in the bloodstream for minutes, days, weeks
- Understand amplitude-modulated and frequency-modulated systems
Hormones secreted by most endocrine glands are AMPLITUDE-MODULATED SIGNALS
- Amplitude is toward hormones; how much of it
- Frequency is how often a signal is sent in a given time (NS)
- Understand the importance of bound vs. unbound hormones
Bound (Lipid-Soluble)
- Nonpolar
- Steroid hormones, thyroid hormones, and fatty acid derivative hormones
- Transport: Small and low solubility.
- Bind to proteins that chaperone the hormone
- Long lifespan
Nonbound (Water-Soluble)
- Polar
- Protein hormones, peptide hormones, most amino acids
- Transport: Large and high solubility
- Can dissolve in blood
- Delivered to target cell without a chaperone
- Short half-life
- Know the chemical classification of hormones
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- Understand the characteristics of the patterns of hormone secretion
CHRONIC HORMONE SECRETION
-Constant blood levels of hormone over a long period of time.
ACUTE HORMONE SECRETION
- When hormone ‘s concentration changes suddenly and irregularly, and its circulating levels differ with each stimulates.
EPISODIC HORMONE SECRETION
- Occurs when hormones are secreted at a fairly predictable interval and concentration
- Know the three methods of regulating hormone secretion.
HUMORAL STIMULI
- Metabolites and other molecules in the bloodstream can directly stimulate the release of some hormones. They circulate in the blood.
- Stuff in blood
- Stimulate and inhibit release- To stop it a hormone has to be secreted to counteract the effects
NEURAL STIMULI
- Following action potentials, neurons release a neurotransmitter into a synapse with hormone-producing cells. The neurotransmitter stimulates the cells to secrete their hormone
- If neurotransmitters are inhibitory then target endocrine gland are secreting
HORMONAL STIMULI
- Occurs when hormones stimulate the secretion of other hormones.
- Most common examples are hormones from the anterior pituitary gland, called TROPIC HORMONES.
- Inhibiting hormones, from the hypothalamus, prevent the secretion of tropic hormones from the pituitary gland
- Know the different types of hormone receptors and how they affect cellular physiology.11. Understand how G protein activation can activate adenylate cyclase.
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DOWN-REGULATION
- Desensitization occurs when the number of receptors rapidly decreases after exposure to certain hormones.
- Remove some receptors so cell becomes less sensitive to the hormone
UP-REGULATION
- Results in an increase in the rate of receptor synthesis in the of receptor synthesis in target cells.
- Add receptors so cell becomes more sensitive to the hormone
Nuclear and Membrane-bound
- Understand how G protein activation can activate adenylate cyclase. (Water soluble)
- Water-soluble hormone goes through blood unbounded.
- Once near a cell, it attaches itself to a specific external receptor FIST MESSAGE
- First message activates the G protein
- G protein actives adenylate cyclase
- Takes ATP and makes into cAMP - cAMP is the SECOND MESSAGE
- cAMP activates a family of proteins called Protein kinase
- Protein kinase adds phosphate to enzymes
- This activates the enzymes and changes the physiology of the cell
- Understand receptors that cause phosphorylation of intracellular proteins.
- cAMP activates a family of proteins called Protein kinase
- Protein kinase adds phosphates to enzymes (PHOSPHORYLATION)
- This activates the enzymes and change the physiology of the cell
- Demonstrate knowledge of signal amplification.
The rate at which a hormone’s response is elicited are determined by its mechanism of action at the receptor. Nuclear receptors work by activationing protein sythisi.
Hormones that stimulate the sythesis of second messengeres can produce an almostinstanteous response beacuse second messenger influences existing enzymes.
-A single hormone hormone activates many second messengers, eachactativaing enzymes that produce an enormous amount of final product.
- Know the chemical classification of hormones
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