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175 Cards in this Set
- Front
- Back
Endocrine glands secrete:
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hormones!
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What are hormones?
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chemical messengers that are transported throughout the body by the bloodstream
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What do exocrine glands excrete?
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non-hormonal substances which pass through ducts to the skin or to structures that communicate with the exterior
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How many ducts do endocrine glands have?
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NONE
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How are hormones released from endocrine glands?
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Released into interstitial fluid then diffused through capillaries
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Which organs have both endocrine and exocrine glands?
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the pancreas, ovaries, and testes
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These are chemical messengers which act on nearby cells ONLY.
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paracrines
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What is the purpose of hormones?
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to regulate the metabolic functions of other cells
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What are the two different bases of hormones?
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most are amino acid based
some are steroid based |
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Amino acid based hormones are derived from:
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amino acid derivatives, peptides, and proteins
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Steroid based hormones are derived from:
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cholesterol
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Steroids are produced by what two structures?
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the adrenal cortex and the gonads
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Each hormone affects only certain cells, known as:
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target cells
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What hormones are considered water-soluble?
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all the amino acid based hormones except for thyroid hormone
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What hormones are considered lipid soluble hormones?
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steroids and thyroid hormone
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How do water-soluble hormones function?
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They bind to specific receptors on the surface of the target cell plasma membrane
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How do lipid-soluble hormones function?
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They pass through the plasma membrane and bind to intra-cellular receptors, which then bind to DNA
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For a target cell to respond to a hormone, it must have the __________ __________ for that particular hormone
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specific receptors
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The degree of target cell response depends on 3 factors:
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1. the blood level of the hormone
2. the relative numbers of target cell receptors for that hormone 3. the affinity of the receptors for the hormone |
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A increase in any of these three factors will cause an _______ in the target cell response
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increase
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Hormones circulate in the blood in two forms:
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free or bound to plasma proteins
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Lipid soluble hormones are usually bound to :
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protein
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water soluble proteins are usually :
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free
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Some hormones are broken down in the target cell, but most are removed by :
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the liver or kidneys
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This is the time required for a hormone's concentration to be reduced by half:
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half-life
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Can the body take hours, sometimes days, to respond to a hormone?
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yes
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Most hormone synthesis and release is regulated through __________ _________ mechanisms:
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negative feedback
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Endocrine gland stimuli may be :
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humoral, neural, or hormonal
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Explain how humoral stimuli work:
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blood levels of specific ions or nutrients produce a direct response
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Give an example of a humoral stimuli:
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PTH
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Explain how neural stimuli work:
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direct stimulation of the gland by nerve fibers
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Explain how hormonal stimuli work:
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the gland responds to a hormone secreted by another gland
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Give an example of a neural stimuli:
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adrenal medulla secretion
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What's another name for the pituitary gland?
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hypophysis
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Where is the pituitary gland located?
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in the sella turcica of the sphenoid bone
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The pituitary gland is connected to the __________ by a stalk called the ____________.
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hypothalamus; infundibulum
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The pituitary consists of 2 lobes known as the:
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anterior and posterior
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The posterior lobe is made of :
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nerve tissue
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The posterior lobe releases ______________, which are made in the hypothalamus
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neurohormones
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The posterior lobe and infundibulum make up the _________________.
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neurohypophysis
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The anterior lobe is also known as the ____________ and is made up of:
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adenohypophysis; glandular epithelial tissue
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The anterior lobe and the hypothalamus are connected by the ________ _______ system:
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hypophyseal portal
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The hypothalamus secretes ___________ and ___________ hormones, which control the anterior pituitary.
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releasing and inhibiting
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The anterior pituitary secretes 6 major hormones:
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TSH, ACTH, FSH, LH, PLN, and GH
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Which hormones secreted by the anterior pituitary are considered tropic?
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TSH, ACTH, FSH, and LH
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Which hormones secreted by the anterior pituitary are considered non-tropic?
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growth hormone and prolactin (PLN)
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What does it mean when a hormone is considered tropic?
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it controls other endocrine glands
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Growth hormone (GH) stimulates :
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bone growth and an increase in muscle mass
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Is growth hormone considered catabolic or anabolic?
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anabolic (builds)
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Production of GH peaks during ________ and declines with ______ .
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adolescence ; age
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Increased secretion of GH in childhood causes :
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gigantism
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Increased secretion after the epiphyseal plates have closed causes :
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acromegaly
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The characteristics of acromegaly are:
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an enlargement of the bones of the hands, feet, and face
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Decreased secretion of GH during childhood causes :
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pituitary dwarfism
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Thyroid stimulating hormone (TSH) stimulates :
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the secretion of thyroid hormone (TH)
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Adrenocorticotropic hormone (ACTH) stimulates:
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the adrenal cortex to secrete corticosteroids, especially glucocorticoids
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Which two hormones are known as gonadotropins?
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Follicle stimulating hormone (FSH) and luteinizing hormone (LH)
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Follicle stimulating hormone (FSH) and luteinizing hormone (LH) regulate the function of the :
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gonads (ovaries and testes)
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Levels of FSH and LH increase during :
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puberty
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Prolactin (PLN) stimulates:
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milk production by breast tissue
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Excessive secretion of endocrine hormones is most commonly due to a :
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neoplasm (tumor) of that gland
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The posterior pituitary secretes two hormones:
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oxytocin and antidiuretic hormone
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Oxytocin stimulates :
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uterine contractions during childbirth
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How is oxytocin helpful in medical situations:
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medically (IV) to induce or speed-up labor
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Antidiuretic hormone (ADH) causes:
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increased reabsorption of water in the DCT and collecting ducts
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The __________ monitors the osmolality of the blood and regulates its release
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Hypothalamus
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At high concentrations, ADH causes:
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Vasoconstriction
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Decreased secretion of ADH causes:
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Diabetes insipidus- high urine output and thirst
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The thyroid is located just inferior to the __________
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Larynx
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How many lobes does the thyroid have? What are they connected by:
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Right and left lobes; by an isthmus
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The thyroid is composed of follicles that are filled with:
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Colloid
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What is colloid composed of?
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Thyroglobulin; a protein that stores thyroid hormone
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Colloid is made by what?
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Follicle cells
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Thyroid hormone is a mixture of what two substances?
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Thyroxine (T4) and triiodothyronine (T3)
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What is the major hormone produced by the thyroid?
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Thyroxine (T4)
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Most t3 is made from _______ in the _________ _________
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T4 ; target tissues
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What does thyroid hormone do?
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Increases basal metabolic rate (o2 consumption by the mitochondria) and body heat production
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Production of thyroid hormone requires the uptake of ________ by the follicle cells
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Iodine
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TSH stimulates the follicle cells to release ______ into the blood, where it is carried by ________ _________
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TH ; transport proteins
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TH is ______ - soluble and binds to receptors in the ________ _______ _________
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Lipid, target cell nucleus
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When blood levels of TH are low, TSH secretion is _________
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Increased
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When blood levels of TH are high, TSH secretion is__________
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Decreased
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Low th levels can be due to what two factors?
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Malfunctioning thyroid gland, or due to a low TSH output
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What are the symptoms of hypothyroidism?
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Cold intolerance, constipation, edema, lethargy, bradycardia
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If the thyroid gland is the cause of hypothyroidism, then:
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The TSH level wil be high.
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This is an enlargement of the thyroid:
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Goiter
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What is goiter caused by:
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Low iodine in the diet ( now present in salt)
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Excess TH is known as :
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Hypothyroidism
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Hypothyroidism causes:
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A high metabolic rate, weight loss, heat intolerance, diarrhea, Nervousness and tachycardia
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Calcitonin is made by the:
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Parafollicular cells
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What is the function of calcitonin?
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To lower the blood calcium levels by stimulating osteoblasts and inhibiting osteoclasts
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Does the uptake of calcium into the bones increase or decrease with the presence of calcitonin?
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Increase
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Parathyroid glands are located on the __________ aspect of the thyroid
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Posterior
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Occasionally parathyroid glands are found in other areas of the _______ or_______
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Neck, mediastinum
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How many parathyroid glands are there usually?
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4 (but can be more or less)
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Parathyroid hormone (PTH) is the most important hormone regulating :
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Blood calcium levels
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Release of PTH causes a(n) increase/decrease in blood calcium levels
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Increase
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Secretion of PTH is stimulated by ? Inhibited by?
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Stimulated by low calcium levels; inhibited by high calcium levels
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PTH works through what 3 target sites?
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Bones, kidneys, and the small intestine
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How does PTH effect osteoclasts? What does this do to calcium levels?
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Stimulates osteoclasts, releases calcium into the blood
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How does PTH effect the renal tubules?
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It increases calcium reabsorption in the renal tubules
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How does PTH affect vitamin D? What does this cause?
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Stimulates vitamin D, more calcium is then absorbed by the intestinal mucosa
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Elevated PTH levels can be caused by what? What does this do to calcium levels?
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Tumors, hypercalcemia
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What are the symptoms of hypercalcemia?
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Thinning of the bones, muscular weakness, kidney stones
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Decreased PTH levels are often caused by what?
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Surgical removal
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Hypocalcemia caused by decreased PTH levels causes what symptoms?
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Severe tetany (muscle spasms) and possible death
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Where are the adrenal glands located?
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At the superior pole of each kidney
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What is the inner medulla of the adrenal gland made out of?
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Nervous tissue
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What type of tissue is the cortex of the adrenal gland made up of?
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Glandular tissue
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The adrenal cortex produces _________ , which are made from __________
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Corticosteroids, cholesterol
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What are the three regions of the adrenal cortex and what do they make?
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1) the outer layer makes mineralocorticoids
2) the middle layer primarily makes gluticosteroids 3) the inner layer primarily makes sex hormones |
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What regulates fluid balance and the electrolyte concentrations of extracellular fluids?
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the mineralocorticoids (mostly aldosterone)
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what is the most important mineralocorticoid?
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aldosterone
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Aldosterone does what to sodium and potassium? where does this occur?
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stimulates sodium reabsorption and potassium secretion
in the renal tubules |
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What does increased reabsorption of sodium do to water levels? What does this do to blood volume and blood pressure?
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increases water reabsorption
increases blood volume and blood pressure |
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Aldosterone secretion is stimulated mainly by :
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the renin-angiotensin mechanism (specifically angiotensin 2)
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Besides the renin-angiotensin mechanism, what stimulates the release of aldosterone?
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low sodium levels and high potassium levels
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Glucosteroids help protect the body from :
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long-term stress
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glucosteroids help protect the body from what SPECIFIC instances?
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major hemorrhages, major trauma, infection
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What is the primary glucocorticoid?
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cortisol
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Secretion of glucocorticoids is stimulated by what?
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ACTH
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glucocorticoids are controlled by what type of feedback mechanism?
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negative feedback
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Stress can also cause an increase in _______ secretion and therefore ________ secretion
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ACTH, cortisol
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The primary effect of glucocorticoids is to ______ blood glucose levels.
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increase
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How do glucocorticoids increase blood glucose levels?
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breaks down proteins
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Once proteins are broken down by glucocorticoids, what happens?
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amino acids are then converted to glucose (gluconeogenesis)
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Are glucocorticoids anabolic or catabolic?
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catabolic
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What do excess glucocorticoid levels do to connective tissue formation? What does this do for trauma to the body?
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depresses it
slow wound and fracture healing |
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glucocorticoids do what to inflammation and the immune system?
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decreases inflammation and supresses the immune system
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How are glucocorticoids medically used?
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to decrease inflammation (in arthritis)
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Excessive glucocorticoid levels cause what condition?
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cushing's syndrome
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What happens to the body during cushing's syndrome?
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elevated blood glucose levels, muscle wasting, moon face, central obesity
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What is the most common cause of cushing's syndrome?
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medical administration of glucocorticoids
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What is another cause of cushing's syndrome?
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pituitary (ACTH) or adrenal tumors
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Another name for adrenal insufficiency is?
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Addison's disease
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Adrenal insufficiency does what to glucocorticoids and mineralocorticoids?
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causes inadequate production
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Addison's disease eventually leads to:
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hypoglycemia, hypoatremia, and hypotension
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What are the sex hormones produced by the adrenal glands? In what sex?
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androgens and estrogens
in both sexes |
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What can happen to women who have an androgen secreting tumor?
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masculinization
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The adrenal medulla makes? What two specifically?
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catecholamines
epinephrine (adrenaline) and norepinephrine |
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The adrenal medulla is part of the _______ _______ system
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sympathetic nervous
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The adrenal medulla helps the body cope with:
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short-term stress
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The adrenal medulla secretes about ______ % epinephrine and _______ % norepinephrine. How similar are their effects?
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80%, 20%
very similar |
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The pancreas contains about 1 million ________ ______ which produce the pancreatic ________
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pancreatic islets
hormones |
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Alpha cells of the pancreas produce:
Beta cells produce: |
glucagon
insulin |
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Alpha cells and beta cells are involved in regulating:
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blood glucose levels
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Glucagon targets the ________ where it promotes the ______ and ______ of glucose into the blood (glycogenolysis), ____ blood glucose levels.
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liver ; production and release ; raising
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Release of glucagon is stimulated by :
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low glucose levels
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Insulin is a ____ amino acid _______
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51, polypeptide
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Insulin is released to ____ blood glucose levels.
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lower
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How does insulin work?
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stimulates insulin receptors, increases the transport of glucose into most cells of the body
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What organs DO NOT require insulin for the transport of glucose?
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the liver, kidneys, and brain
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What is glucose stored as?
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glycogen or fat
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Insulin is a(n) anabolic or catabolic hormone?
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anabolic
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Insulin is stimulated by ___ blood glucose levels
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increased
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This condition results from decreased secretion of insulin or from decreased cellular response:
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diabetes mellitus
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What happens to glucose levels in the urine in a person with DM?
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increase (spilled into urine)
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Without insulin, cells must utilize _____ for energy:
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fats
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when cells utilize fats for energy, they produce organic acids known as:
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ketone bodies or ketones
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Excessive amounts of ketones can cause ________
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ketoacidosis (life-threatening)
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The 3 cardinal signs of diabetes mellitus:
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polyuria, polydipsia, polyphagia
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polyuria is due to:
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incomplete reabsorption of glucose in the renal tubule
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polyuria causes _____ ______ leading to _____ and _____ imbalance
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osmotic diuresis
dehydration and electrolyte imbalance |
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polydipsia is due to:
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dehydration and increased osmolality
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polyphagia is due to:
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inadequate glucose within the cells
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hypoglycemia can cause ____ sympathetic output and ____ mental functioning
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increased, decreased
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type 1 is seen in _______ and is due to:
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children; autoimmune loss of beta cells
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Is there any insulin produced in type 1 diabetes?
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no
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Patients with type 1 DM are prone to _____ and require ______ administration
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ketoacidosis (DKA)
insulin |
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Approximately how many DM cases are type 2?
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90%
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Is type 2 hereditary? What other factors increase type 2 DM?
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yes, obesity and lack of exercise
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Is there any insulin produced in type 2 diabetes?
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yes
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In type 2 DM, the cells do not respond normally. what is this called?
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insulin resistance
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Is DKA still commonly seen in type 2 patients? Is insulin admin. required?
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no, no
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The major complications of DM include :
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atherosclerosis and neuropathy (nerve damage)
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