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97 Cards in this Set
- Front
- Back
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What hormone is not part of a negative feedback loop?
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Oxytocin
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What regulates the concentration of glucose in the blood?
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Insulin and glucagon
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Insulin is released when there are what?
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High levels of glucose in the blood and stimulates glycogen formation and body cells to take up glucose from the blood
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Insulin is a hormone that does what?
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Makes you fat because it stimulates the conversion of carbohydrates and glucose into fat
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What happens when glucose levels drop?
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Glucagon stimulates glycogen breakdown and converts glycogen into glucose in the liver. rasing blood glucose concentration
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What is the negative feedback of the parathyroid gland?
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releases parathyroid hormone (PTH) → which increase Ca+ levels.
*If low Ca+ levels then PTH is released. *If high Ca+ levels then PTH is reduced. |
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What increases calcium uptake in the intestines?
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PTH + Vitamin D
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How does PTH affect the bones?
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PTH stimulates the bone to release Ca+ from the bone and to be more soluble so that it can uptake hydroxylapatite
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Where is the pineal gland located?
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above the hypothalamus
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What hormone does the pineal glad secrete and what does it regulate?
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melatonin, which regulates sleep and wake cycles/circadian rhythms
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What inhibits melatonin secretion?
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light, specifically bright blue light
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What are the two hormones the pituitary gland releases?
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Oxytocin and ADH (Antidiuretic Hormone)
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What does Oxytocin do?
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increases uterine contractions, increased milk letdown, increase bonding, orgasm
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What is the mechanism for ADH?
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*Increases aquaporins in the kidneys → increase water reabsorption.
*Stimulatse thirst, decreases volume of urine → increase urine concentration |
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The body has two portal systems, where are they located?
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1. the hypothalamus
2. GI tract with the liver |
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What are the hormones released by the anterior pituitary?
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Growth Hormones, Porlactin, Melanocyte Stimulating Hormone, Thyroid Stimulating Hormone, Adrenocortic Tropic Hormone, FSH and LH
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The growth hormones (GH) stimulates?
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stimulate growth of all its target organs (esp. long bones). The bones produce growth cartilage and lengthens/thickens the bone
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What does Prolactin stimulate?
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stimulates breasts to develop and stimulate breast cells to produce milk (NOT milk letdown)
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What is prolactin stimulated by?
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mecahanoreceptors in the nipples. When a baby begins suckling. it stops dopamine secretion.
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How does prolactin serve as a contraceptive?
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It inhibits ovulation by suppressing the secretion of hypothalamic gonadotropin releasing hormone (GnRH) → decrease in FSH and LH. It inhibits ovaries to ovulate and women who are nursing cannot get pregnant
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Tumors in the pituitary gland can cause? why?
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It can cause sterility because both male and female produce milk becasue of overstimulation of prolactin due to the tumor.
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What do MSH target and regulate?
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It targets pigment cells in skin and regulates appetite
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The Thyroid stimulating Hormone (TSH) is stimulated by what?
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hypothalamic thyroid releasing Hormone (TRH)
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TSH stimulates what?
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The thyroid gland to release thyroid hormone triiodothyronine and thyroxine (T3 and T4)
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What are the effects of TH?
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-Increases metabolic rate
-involved in development |
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What are the effects of lack of TH (T3 & T4)?
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-cause slow metabolic rate, increase obesity, lethargic, sensitive to cold
-can lead to problems with growth, mental retardation, no myelination of axons. |
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TH (T3 & T4) inhibits what?
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The release of TRH (of the hypothalamus) and TSH (of the thyroid gland)
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What happens when there's lack of iodide?
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Without iodide the thyroid gland cannot synthesize TH's and there for there is no negative feedback onto hypothalamus or ant. pituitary. Therefore, the pituitary continuously secretes TSH which can cause thyroid gland to enlarge.
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What does it stand for ACTH?
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Adrenocortic Tropic Hormone.
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Anterior pituitary releases ACTH to stimulate the adrenal glands that release what three types of hormone?
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Glucocorticoids: cortisol, Mineralcorticoids: aldosterone, Androgens: testosterone
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What is cortisol?
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It is a stress hormone. This is necessary for life.
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What are the effects of glucocorticoids?
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-Involved in regulating blood pressure: it enables the functioning of receptors that regulate the contractility of blood vessels of smooth muscle.
-has metabolic effects -lowers the immune response (important for transplants) -has anti-inflammatory effects. |
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What are the effects of mineralcorticoids?
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-increases Na+ reabsorption in the kidneys (decrease Na+ release) by altering the gene expression for Na+ channels and transporters in the kidneys.
-Increases K+ secretion -Stimuli for secretion of aldosterone is drop in blood pressure and increased circulating K+ions |
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What stimulates the secretion of aldosterone?
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Low blood volume or pressure leads to production of angiotensin II which stimulates the secretion of aldosterone
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What is androgen a precursor to?
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The female hormone, estrogen. e.g. body builders that take steroids may develop breasts.
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Stimulation of the anterior pituitary releases LH or FSH, what causes this stimulation?
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Stimulation by hypothalamic gonadotropin releasing hormone (GnRH)
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What does FSH stimulate?
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maturation of an oocyte in females and stimulates maturation of sperm cells in males
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What does LH stimulate?
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stimulates synthesis and secretion of respective sex hormones in both male and female.
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Thin filaments consists of what?
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actin
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Thick filaments consists of what?
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myosin heads, the myosin head hydrolyzes ATP ---> ADP + Pi (high energy conformation)
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Define a sarcomere.
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The basic contractile unit of muscle. The sarcomere has a distance of two Z lines
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What is the M line?
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The center of symmetry
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What happens when a muscle contracts?
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Neither the thick or thin filaments change length when the sarcomere shortens; rather, the filaments slide past each other, increasing the overlap of the thick and thin filaments.
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What stimulates muscle contraction?
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-Tropomyosin: covers actin binding sites at rest
-Troponin: Calcium sensing protein. Has calcium binding site. |
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Once calcium binds to troponin what happens?
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it moves tropomyosin out of the way so that myosin head can bind actin.
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Why do receptors need to have a high affinity for a hormone?
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Because hormones act on very small concentrations.
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There are three types of signaling, what are they?
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Endocrine, Paracrine, and Autocrine.
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Define paracrine signaling
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secreted molecules diffuse locally and trigger a response in the neighboring cells.
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Define autocrine signaling
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secreted molecules diffuse locally and acts on itself
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Define Endocrine signaling
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secreted molecules diffuse into the bloodstream and tirgger responses in target cells anywhere in the body
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What is a tropic hormone and which hormones are they?
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A tropic hormone stimulate endocrine glands to release another hormone which affects the target cells. FSH, LH, ACTH, TSH
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What is a nontropic hormone and which hormones are they?
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Non-tropic hormones act directly on the target cells. MSH, GH, and Prolactin
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What are water soluable hormones?
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They can not cross the lipid bilayer. Because they cannot cross the bilayer, they are exocytosed (like NTs) from vesicles and goes into the bloodstream where it can bind to membrane receptors.
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What are lipid soluble hormones?
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Can cross the lipid bilayer (steroids). Does not require receptors on the surface of the membrane for these types of hormones because it can just cross the bilayer.
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Hormones can have mulitple effects, give an example of one?
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Epinephrine has alpha and beta recpetors. It simultaneously triggers glycogen breakdown, increased bloodflow to skeletal muscles, and decrease bloodflow to the GI tract.
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The parathyroid gland secretes PTH, which increases blood calcium levels, how?
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By breaking down the minerals in your bones
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The pineal gland secretes what hormone to regulate sleep cycles?
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melatonin
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Melatonin is stimulated in the dark by special photoreceptors in the eye called what?
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melanopsins, that synapse with the pineal gland
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THe posterior pituitary secretes ADH to?
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increase water absorption in the kidneys and oxytocin to act in a positive feedback loop during childbirth
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ADH and Oxytocin are originally secreted by what?
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the hypothalamus, which has axons that extend into the posterior pituitary gland.
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The anterior pituitary gland connects with the hypothalamus through what kind of system?
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A portal vein system, blood flows from capillary beds into venuoles instead of going back to arterioles like it does in the rest of the body.
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Length of bones becomes permanent once all of the what has been converted to bone.
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growth cartilage
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Prolactin is regulated by secretion of dopamine meaning?
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Low dopamine secretion means high prolactin secretion.
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TSH stimulates the thyroid gland to produce T3 and T4, theses hormones are complete with what element?
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iodide
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Thyroid hormones stimulates what?
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metabolism and contributes to organism development
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What stimulates the adrenal cortex to secrete it's own hormones?
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ACTH
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The secretion of GnRH by the hypothalamus causes the anterior pituitary to secrete what?
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LH and FSH
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What hormone decreases the sensitivity of the pituitary gland to GnRH, causing temporary decreased fertility?
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Prolactin
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What does FSH stimulate?
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the growth of the oocyte in females and the spermatozoa in males
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What does LH stimulate?
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ovulation in females and testosterone production in males
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What are the four man effects of glucocorticoids?
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1. regulates blood pressure
2. anti-inflammatory effects 3. suppresses your immune response 4. increases blood glucose levels (glucagon) |
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How does mineralocorticoids increase blood pressure?
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By increasing the NA+ retention and K+ excretion in the kidneys
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In a relaxed muscle, actin and myosin myofilaments lie side-by-side. During contraction what happens?
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The actin and myosin myofilaments interact. The actins are pulled toward the center of each myosin myofilament. As a result the sarcomeres shorten.
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In the fully contracted muscle what happens?
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The ends of the actin myofilaments filaments overlap
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Muscle contraction is caused by what?
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actin filaments sliding past myosin filaments
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What does PTH stimulate?
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It stimulates the dissolution of bone, making Ca2+ soluble
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When Ca2+ decreases, PTH secretion...
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Increases, and Ca2+ increases
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Light receptors in the retina called melanopsins excited by blue light which...
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Decreases melatonin secretion.
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What does Oxytocin do?
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-increases uterine contractions
-increases milk letdown -bonding between mother and child -Orgasm during intercourse |
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What doe Antidiuretic hormones (ADH) do?
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increase aquaporins in kidneys, therefore, increasing water reabsorption.
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Where are the two portals in the body?
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-between hypothalamus and posterior pituitary
-gastrointestinal tract and liver. |
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The integrating system which is known as the hypothalamus regulates GH by?
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secreting 2 hormones: one increase GH secretion while the other decreases GH secretion from the anterior pituitary
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How does the hypothalamus regulate prolactin?
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by secreting dopamine which decreases prolactin secretion.
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What inhibits the hypothalamus from secreting dopamine?
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suckling of the nipple which is stimulus for mechanoreceptors.
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What hormone regulates appetite?
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MSH
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After menopause what is the only source of androgens. This no longer produces estrogens and progesterone?
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The adrenal cortex
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What are the two gonadotropins that are secreted during the embryonic period, when the hypothalamus produces GnRH which causes the pituitary to be stimulated?
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FSH and LH
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What are the three types of muscle tissue?
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-Skeletal-striated; attached to bone via tendons
-Cardiac-striated; heart -Smooth-non striated; lines hollow organs |
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What is myosin?
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It is a main muscle protein and enzyme that breaks down ATP that makes up thick filaments
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What is actin?
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protein found in thin filaments that activates myosin
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When muscles contract do they slide or push?
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slide
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Does the length of the filaments shorten?
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no, always stays the same
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Does the length of the sarcomere shorten?
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yes it does
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What two proteins in muscles act as switches for muscle contractions?
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troponin and tropomyosin
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What are the actions of Adrenocorticotropin (ACTH)
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It targets the adrenal cortex and stimulates secretion of steroid hormones
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Mineralocorticoids decrease blood pressure and do what?
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increase circulating K+ levels.
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How do mineralocorticoids do what they do?
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It alters gene expression of Na+ channels and transporters, K+ channels, and Na+/K+ pumps.
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