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56 Cards in this Set
- Front
- Back
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exocrine (secrete out)
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secrete into ducts which lead to a body cavity, organ lumen or body surface.
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EXOCRINE II
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saliva, mucous, digestive glands, sweat (sudoriferous), oil (sebacous)
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ENDOCRINE ( SECRETE WITHIN)
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secretes hormones into extracellular fluid----diffuse into blood capillaries. NO DUCTS.
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WHAT ARE THE ENDOCRINE GLANDS?
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Pituitary, pineal, thyroid, parathyroid, adrenal
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WHAT ARE THE ORGANS THAT HAVE SOME ENDOCRINE TISSUE?
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thymus, pancreas, gonads (ovaries, testes), hypothalamus (neuroendocrine gland), stomach, small intestine, kidneys, heart, placenta
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WHAT IS A HORMONE?
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chemical synthesized by an organ that causes target cells to respond
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WHAT IS THE FUNCTION OF A HORMONE?
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To maintain homeostasis by changing the rate at which target cells perform activities they can already do. Hormones do not cause cells to do new things.
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WHAT ARE THE THREE TYPES OF HORMONES?
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circulating, local and environmental
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WHAT IS THE SUB GROUP OF THE CIRCULATING HORMONE?
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endocrines: chemical messengers are secreted into bloodstream by certain glands and cells, affects cells that are distant from source---target organs
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WHAT IS THE FIRST SUBGROUP OF LOCAL?
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Paracrines, act locally on nearby cells. These chemical messengers are secreted by one cell type into extra cellular fluid and affects surrounding cells. (ACTS ON DIFFERENT TYPE OF NEIGHBORING CELLS)
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WHAT IS THE SECOND SUBGROUP OF LOCAL?
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Autocrines, the messenger stimulates the cell that originally secreted it. (SAME TYPE OF CELL TYPE THAT SECRETES THEM)
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WHAT IS ENVIRONMENTAL?
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pheromones secreted into the environment to modify behavior and physiology.
--found in urine of dog and cat used as olfactory fertility signal ---a women can influence menstrual cycle length of another women |
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DEFINE RECEPTORS
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Hormones exert their action by binding to a protein called receptors
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WHAT IS THE COMPOSITION OF A RECEPTOR?
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A large protein or glycoprotein molecules to which hormones bind
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WHERE ARE RECEPTORS FOUND?
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In the cell membrane of target cells (membrane bound receptors)
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WHAT ARE MEMBRANE BOUND RECEPTORS ALSO KNOWN AS?
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intramembranous or fixed receptors
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WHERE ELSE ARE INTRAMEMBRANOUS OR FIXED RECEPTORS LOCATED?
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Polar, h2o soluble hormones. For peptide, protein, glycoprotein, catecholamines (Epinephrine, Norepinephrine)
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WHERE ELSE ARE RECEPTORS FOUND?
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In cytoplasm or nucleus of target cell are called intracellular receptors (mobile receptors).
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WHAT ARE MOBILE RECEPTORS FOR?
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non-polar lipid soluble hormones, steroid and thyroid
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RECEPTORS AND HORMONES ARE HIGHLY__________?
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Specific (specificity). The tendency for each type of hormone to bind to one type of receptor, and not to others.
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Number of receptors?
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2000-100,000
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Define blocking hormone receptors?
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synthetic hormones block receptors, similar hormone to attach but without the hormone affects.
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Example of Blocking hormone receptors
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Tamoxifen--blocks estrogen receptors to; prevent or delay breast cancer.
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what are the endocrine signals?
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Amplitude-modulated signals: hormone concentration increases and decreases in body fluids.
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what are the nervous system signals?
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Frequency-modulated signals: The more frequent the stronger the response, vary in frequency but not in amplitude.
---# of all or none AP, along axons -----weak signals=lower frequency of AP -----STRONG SIGNALS=higher frequency of AP |
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what is the structure of polar (h20 soluble/hrdrophyllic structure?
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Polar hormones cannot diffuse through the non-polar biphospholipid layer of the plasma membrane; they must bind to polar cell membrane-bound receptors (protein/glycoprotein)
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what are the other polar structures?
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-amines
-peptides, proteins or glycoproteins -Eii\cosanoid |
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what are the sub units of amines?
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Amines are derived from amino acids.
1) catecholamines from adrenal medullla----derived from tyrosine (aa) -------e & n.e 2)Melatonin: from pineal gland----derived from tryptophan (aa) |
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what are the sub units of peptides, proteins, glycoproteins?
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synthesized on rough E.R and golgi apparatus
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what is the sub unit of eicpsanoid? (derived from 20c fatty arachidonic acid
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lipid
usuallly local hormones (paracrines and autocrines) prostoglandins, thromboxins, leukotrienes |
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what is the hormone structure of non-polar--lipid soluble ---hydrophobic?
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these non-polar hormones can diffuse through the non-polar biphospholipid layer of the plasma memebrane and bind to the intracellular receptors in the cytoplasm of the nucleus.
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what is the sub unit of thyroid? derived from tyrosine
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amine
-thyroid hormones (T3 & T4) |
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what is the sub unit of steroid? derived from cholesterol
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-lipid
-endocrine tissue that secretes steroid hormones, derived from mesoderm -synthesized in both mitochondria and smooth E.R |
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how do h20 soluble polar hydrophillic transport in the blood?
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most are transported free in the blood (unbound)
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how do lipid soluble non polar hydrophobic transport in the blood?
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transport bound and free in the blood?
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what is a bound fraction?
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transported bound to plasma proteins called binding proteins, which are transported by the liver.
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what is the function of a bound fraction?
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lrg size & polarity retards filtering of hormone in kidney which slows rate of hormone loss in urine
provides ready reserve of hormones in blood (reversible reaction dynamic equilibrium) |
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what is a free fraction?
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.1%-10% is free to diffuse out of the capillaries into target cells
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how does a hormone exit a capillary?
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only free hormones can diffuse through the capillary wall and binds to target tissues--size, polarity
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how do non polar hormones exit a capillary?
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readily diffuse through the capillary endothelium biphospholipid layer / simple squamous epithellium
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how do polar hormones exit a capillary?
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pass through the pores (fenestrae) in capillary endothellium
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blood concentration of hormones are degraded by enzymes in:
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-target cells
-liver, kidney -circulatory system ( blood) (broken down by enzymes in the target cell) |
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blood concentration of hormones are excreted by?
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-hormone may be modified enzymatically and excreted
-liver in bile--small intesteine--feces -kidneys in urine (helps with digestion liver makes juices, bile) |
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in kidney failure what happens to blood hormonal level?
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not getting rid or hormones fast enough as able to be produced
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define the half life of a hormone?
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length of time to eliminate half of a hormone from the circulatory system
---used to predict the rate of hormone elimination from the body |
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purpose of half life in polar hormones?
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-short half life
-degraded rapidly-blood concentrations increase and decrease rapidly -regualtion rapid-onset short- duration activites -the carbohydrate of the glycoprotein hormones protects them from proteolytic enzymes in the circulation increasing their half life |
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purpose of half life in non polar hormones?
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-longer half life
-combine with plasma protein slows rate of diffusion through blood vessel wall which increase the half life -blood concentration maintained constant level |
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what are the three basic patterns of hormone levels in the blood?
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constant, stimulus, cyclic
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define constant?
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always need---thyroid hormones for metabolism (bound/ half life increase) (chronic)
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define stimulus?
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temporary need-- (sudden change) epinephrine during stress or exercise (acute)
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define cyclic?
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needs repeats with regularity--female reproductive hormones (episodic)
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what 4 stimuli to gland cells regulate hormone secretion?
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humoral, neual, hormonal, negative and positive feedback
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what is humoral stimuli?
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chemical substances in the blood (ions and nutrients) act on gland
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Neural stimuli
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neurons synapse with endocrine gland cells and may either increase or decrease hormone secretion
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hormonal stimuli
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neurons synapse with endocrine gland cells and may either increase or decrease hormone secretion
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negative feedback?
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the most important means of controlling hormone secretion
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