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50 Cards in this Set
- Front
- Back
How do exocrine and endocrine glands differ?
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Exocrine glands secrete their products into ducts that carry the secretions into body cavities, into the lumen of an organ, or to the outer surface of the body.
Endocrine glands secrete their products into the interstitial fluid surrounding the secretory cells. From there, hormones diffuse into blood capillaries and the blood carries them to target cells throughout the body |
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What is a hormone?
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A mediator molecule that is released in one part of the body but regulates the activity of cells in other parts of the body.
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How does the Endocrine System compare to the Nervous system?
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ES is slower but it's effects generally last longer.
Neurotransmitters usually act locally; hormones usually act on distant organs NS acts on muscles and glands; ES acts on many kinds of cells throughout the body. |
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Name two mediators that can act as both a Neurotransmitter and a Hormone
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NorEpinephrine and Nitric Oxide
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Which organs are exclusively endocrine?
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Pituitary
Thyroid Parathyroid Adrenal Pineal |
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List the functions of hormones
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Help regulate metabolism
Control growth and development Regulate operation of reproductive systems Help establish circadian rhythms |
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Generally how many receptors does a target cell have for a particular hormone
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2000 to 100,000
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If a hormone is present in excess, the number of target cell receptors may decrease. This effect is called?
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Down Regulation
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True or False: Down regulation makes a target cell less sensitive to a hormone
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TRUE
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When a hormone is deficient, the number of target cell receptors may increase. This effect is called
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Up Regulation
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True or False: Up regulation makes a target cell less sensitive to a hormone
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FALSE
Up regulation increases receptors in a target cell |
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What is a circulating hormone?
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Hormones that pass from the secretory cells that produce them into interstitial fluid and then the blood
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True or False:
Most hormones are Circulating Hormones |
True
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Local hormones that act on neighboring cells are called?
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Paracrine
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Local hormones that act on the same cell that secreted them are called?
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Autocrine
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Can a hormone be both Paracrine and Autocrine?
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Yes. Interleukin 2 acts on other nearby cells as well as on the cell the produced it.
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What is vasodilation
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An increase in blood vessel diameter
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What are the Lipid Soluble hormones?
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Steroids (Aldosterone, Cortisol, Androgens, Calcitriol, Testosterone, Estrogens, Progesterone)
Thyroid Hormones T3 and T4 The gas Nitric Oxide |
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What are the Water Soluble hormones
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Amine Hormones
Peptide and Protein Hormones Eicosanoid Hormones |
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Name three catecholamines:
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Epinephrine
Norepinephrine Dopamine |
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What are the functions of Transport Proteins
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1. They make lipid soluble hormones temporarily water soluble for travel in blood
2. Retard filtration in kidneys reducing hormone loss in urine 3. Provide a reserve of hormone in the blood |
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Insulin stimulates synthesis of ?
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Glycogen in liver cells
Triglycerides in adipose cells |
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Where are the receptors for lipid soluble hormones located
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They are located within the target cell in the cytosol or the nucleus
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Where are the receptors for water soluble hormones located
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They are located on the plasma membranes of target cells
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Endothelial cells lining blood vessels secrete what hormone
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Nitric Oxide
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Aldosterone, Cortisol and Androgens are secreted from the?
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Adrenal cortex
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Calcitriol is secreted from the
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Kidneys
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Testosterone is secreted from the
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Testes
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Estrogens and Progesterone is secreted from the
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Ovaries
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T3 and T4 are secreted from what gland and speciafically from what cells
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Follicular Cells within the Thyroid gland
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The Catecholamines are secreted from the
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Adrenal Medulla
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The Pineal Gland secretes what hormone
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Melatonin
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What hormones does the pancreas secrete
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Insulin, Glucagon, Somatostatin, pancreatic polypeptide
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Mast cells in connective tissue secrete what hormone
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Histamine
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Blood platelets secrete what hormone
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Serotonin
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Oxytocin and ADH are secreted from
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The Posterior pituitary (Neurohypophysis)
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What hormones are secreted by the Adenohypophysis?
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HGH
TSH ACTH FSH LH PRL MSH |
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What gland produces Calcitonin, specifically what cells
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The parafollicular cells of the Parathyroid gland
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The stomach and small intestine secrete what hormones?
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Gastrin
Secretin Cholecystokinin GIP |
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Erythropoetin is secreted from
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Kidneys
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Describe the mechanism of action of lipid-soluble hormones
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1. Hormone diffuses thru the lipid bilayer of the plasma membrane into a cell
2. Hormone binds to and activates receptors within the cytosol or nucleus which alters gene expression turning specific genes on or off 3. Transcription then translation, new enzymes are made which alter cellular activity. |
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Describe the mechanism of action of water-soluble hormones
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1. hormone binds to a receptor on the cell membrane (first messenger)
2. Binding creates a G protein 3. G protein activates Adenylate Cyclase which converts ATP into cAMP (second messenger) 4. cAMP activates protein kinases 5. Protein kinases phosphorylate cellular proteins, turning them on or off 6. Phosphodiesterase inactivates cAMP 4. |
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What three ways do hormones interact with each other
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1. PERMISSIVE: where 2 or more hormones must simultaneously react with target
2. SYNERGISTIC: where 2 hormones together have a greater effect than either alone 3. ANTAGONISTIC: where 2 hormones oppose each other |
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True or False. Most hormones are regulated by positive feedback mechanisms
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False.
They are mostly regulated by negative feedback mechanisms |
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Name 3 ways that hormone secretions are regulated
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1. Signals from the Nervous System
2. Chemical changes in the blood 3. Other hormones |
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What is the major link between the Nervous System and the Endocrine System?
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The Hypothalamus
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What hormones does the Hypothalamus make?
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OT and ADH which are stored in the posterior pituitary
5 Releasing hormones: GHRH, TRH,GnRH,PRH,CRH 2 inhibitory hormoes: GHIH/somatostatin, PIH/dopamine |
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What controls the pituitary gland?
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The Hypothalamus
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The Pituitary is also referred to as
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The Hypohysis
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The stalk that connects the hypothalamus to the hypophysis is
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The infundibulum
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