BIOL-242 Lecture Notes - Lecture 2: Adrenal Gland, Endocrine Gland, Parathyroid Gland

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amethysthornet940

16 Apr 2020

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Relative number of receptors on or in target cell. Affinity of binding between receptor and hormone. Target cells must have specific receptors to which hormone binds, for example. Acth receptors found only on certain cells of adrenal cortex. Thyroxin receptors are found on nearly all cells of body. Up-regulation // target cells form more receptors in response to low hormone levels. When hormone levels low, make more receptors. Down-regulation // target cells lose receptors in response to high hormone levels. Ex: concentration of calcium, homeostasis of ca2+ in blood. Stimulus is falling blood ca2+ levels parathyroid glands release parathyroid hormone (pth) osteoclasts degrade bone matrix and release. Endocrine gland stimulated to synthesize and release hormones in response to. The changing blood levels of ions and nutrients directly stimulate secretion of hormones // small molecules that flow in the blood. Declining blood ca2+ concentration stimulates parathyroid glands to secrete pth. Pth causes ca2+ concentrations to rise and stimulus is removed.

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Key: A.Increase

B.Decrease

C. Remain thesame

For questions 19-20 use the following information Thyroid-stimulating hormone (TSH) is secreted from the anterior pituitarygland and acts on the thyroid gland to increase the secretion ofthyroid hormones. Thyroid hormones, on the other hand, have anegative-feedback effect on TSH secretion (See Fig. 16.8 in yourtext). For a person having normal thyroid function, the rate atwhich TSH and thyroid hormones are secreted remains within a normalrange of concentrations. In some people, however, the immune systembegins to produce an abnormal substance that functions likeTSH.

Predict what that substance will do to:

19. _____the rate of thyroid stimulating hormone secretion

20. _____ the rate of thyroid hormone secretion.

For question 21 use the following information. Background:Hormones are dissolved in blood plasma and transported either in afree form or bound to plasma proteins. Hormones that are lipidsoluble, such as steroids and thyroid hormone, circulate in theblood in combination with these plasma proteins. Hormones that bindto plasma proteins do so in a reversible fashion according to theequation:

H + BP <-----------> HBP

(Hormone) (BindingProtein) (Hormone bound to binding protein)

An equilibrium is established between the free plasma proteinsand the hormones bound to the plasma proteins. This equilibrium isimportant because only a free hormone is able to diffuse throughcapillary walls and bind to target cells. The combination of ahormone bound to a binding protein reduces the rate at which theydiffuse through the walls of capillaries.

This increases the half-life of the hormone. The half-life isthe length of time it takes to eliminate half a dose of a substancefrom the circulatory system. The half-life of a hormone is astandard measurement used by endocrinologists because it allowsthem to predict the rate at which a given hormone will beeliminated from the body.

21. _____How is the half-life of a hormone affected by adecrease in the concentration of the

specific plasma protein to whichthat hormone binds? Remember if the time to

eliminate a hormone from theblood stream is longer then the half life has increased.

If the time to eliminate ahormone shortens then the half life has decreased

22. _____Consider a hormone that is secreted in large amounts ata given interval, modified

chemically by the liver, andexcreted by the kidney at a rapid rate, making the

half-life of the hormone in thecirculatory system very short. The hormone therefore

rapidly increases in the bloodand then decreases rapidly. Predict the

consequences of liver and kidneydisease on the blood levels of that hormone.

For question 23 use the following background information:Periodic increases in the sensitivity of some tissues to certainhormones is called up-regulation. It results from an increase inthe rate of receptor molecule synthesis. In many tissues the numberof hormone receptors rapidly decreases after exposure to certainhormones. This is called down-regulation.

Problem. Estrogen is a hormone secreted by theovary. It is secreted in greater amounts after menstruation and afew days before ovulation. Among its many effects is causing

up-regulation of receptors in the uterus for another hormonesecreted by the ovary called progesterone. Progesterone is secretedafter ovulation. A major effect of progesterone is to cause theuterus to become ready for the embryo to attach to its wallfollowing ovulation. Pregnancy cannot occur unless the embryoattaches to the wall of the uterus.

23. ______Predict the consequences on becoming pregnant if theovary secretes too little

estrogen?

24. ______ Predict the effect of inadequate dietary intake ofcalcium on PTH secretion

25. ______ Predict the effect of inadequate dietary intake ofcalcium on Calcitriol secretion

violetspider457

1. In order for a hormone to cause a response, it must first bindto an appropriate receptor on its target cell. (Points: 1)
True
False

2. Disorders associated with the endocrine system can be caused byproblems with hormone production or lack of receptors for thehormones on the target cells. (Points: 1)
True
False

3. The levels of potassium and sodium in the body are regulatedprimarily by the hormone aldosterone. (Points: 1)
True
False

4. Nitric oxide is produced by cells lining the blood vessels; thischemical messenger regulates the contraction of smooth muscle inthe digestive tract as well as local blood flow in various tissuesof the body. (Points: 1)
True
False

5. Uptake of blood glucose by liver cells is stimulated by (Points:1)
ADH
prolactin
parathyroid hormone
glucagon
insulin

6. Which of the following is true regarding estrogen andprogesterone? (Points: 1)
They are secreted by the ovaries.
They are released during a female's reproductive years.
They regulate the menstrual cycle.
They stimulate the development of female secondary sexcharacteristics.
all of the above

7. Which of the following is not a symptom of diabetes mellitus?(Points: 1)
blurred vision
high sodium concentration in the blood and urine
excessive thirst
tingling in the feet or hands
fatigue

8. Which of the following is required in the diet in order foractive thyroid hormones to be produced? (Points: 1)
calcium
phosphorus
iodine
zinc
iron

9. Which of the following nonhormonal chemical messengers isimportant in local control of blood flow and blood clotting?(Points: 1)
prostaglandins
nerve growth factor
tumor angiogenesis growth factor
histamine
epidermal growth factor

10. If diabetes is left untreated, which of the following coulddevelop as a result? (Points: 1)
neural disorders
kidney failure
blindness
cardiovascular disorders
all of the above

11. The process by which the blastocyst becomes buried within theendometrial lining of the uterus is: (Points: 1)
fertilization.
implantation.
morphogenesis.
differentiation
embryonic development.

12. The placenta forms from embryonic tissue and (Points: 1)
bone marrow
amniotic fluid
embryonic disk
endometrium
yolk sac

13. Which of the following organs is not fully developed in a fetusand is therefore bypassed by the ductus aerteriosus? (Points:1)
liver
pancreas
heart
lungs
bladder

14. During puberty, the secretion of GnRH causes the secretion of________, which in turn stimulate(s) the production of sexhormones. (Points: 1)
LH and FSH
oxytocin and prolactin
insulin
growth hormone
oxytocin and growth hormone

15. Research on the aging process shows that wounds of the elderlyheal more slowly and that they are more susceptible to disease.These are problems associated with an aging ________ system.(Points: 1)
respiratory
immune
integumentary
digestive
endocrine

________________________________________

cyanwoodchuck896

QUESTION 1

Which of the following is an example of an extracellular signal molecule?

	a.	IP₃
	b.	cAMP
	c.	Insulin
	d.	Diacylglycerol

2 points

QUESTION 2

Nuclear hormone receptors _____

	a.	Bind to water soluble ligands
	b.	Activate second messengers
	c.	Regulate transcription in response to ligand binding
	d.	Are normally located on the plasma membrane

2 points

QUESTION 3

Which of the following does not occur when a receptor tyrosine kinase is bound by ligand?

	a.	Phosphorylation of the RTK
	b.	Cytoplasmic proteins bind the phosphorylated RTK
	c.	Dimerization of the RTK
	d.	The RTK binds to DNA to regulate transcription

2 points

QUESTION 4

Which of these is a logical signal-transduction pathway?

	a.	An intracellular receptor activates phospholipase C, which cleaves a membrane protein to form IP₃, which then activates the opening of an ER channel protein, which releases cyclic AMP into the cytoplasm, where it binds to an intracellular enzyme that carries out a response.
	b.	A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP₃, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response.
	c.	An ion-channel receptor opens, allowing a steroid hormone to enter the cell; the steroid hormone then activates protein kinases that convert GTP to GDP, which binds to an intracellular enzyme that carries out a response.
	d.	A tyrosine-kinase receptor activates adenylyl cyclase, which activates phospholipase C, which converts ATP into cyclic AMP, which binds to an intracellular enzyme that carries out a response.

2 points

QUESTION 5

Which of the following is an example of signal amplification?

	a.	activation of an enzyme molecule
	b.	activation of a specific gene by a growth factor
	c.	Breakdown of many cAMP molecules
	d.	activation of 100 molecules by a single signal binding event

2 points

QUESTION 6

Consider a signal transduction pathway that utilizes cAMP as a second messenger to activate PKA (Protein Kinase A). Which of the following situations will result in the cellular response?

		The G protein releases GDP and binds to GTP
		The target protein (adenylyl cyclase) is inactive
		The regulatory subunits of PKA (Protein Kinase A) are bound to the catalytic subunits
		The appropriate G protein is bound to GDP

2 points

QUESTION 7

Which of the following is found in only some signal transduction pathways? [In other words, which is not found in all signal transduction pathways?]

		Receptor protein
		Extracellular signal molecule
		Intracellular signaling molecule
		Cellular response
		Effector protein

2 points

QUESTION 8

The enzyme that specifically catalyzes the conversion of ATP to cAMP is:

		Adenylyl phosphatase
		Adenylyl kinase
		Adenylyl dehydrogenase
		Adenylyl cyclase

2 points

QUESTION 9

If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?

		It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would employ a transduction pathway directly from an external messenger.
		It would be able to carry out reception and transduction but would not be able to respond to a signal.

2 points

QUESTION 10

A hormone signal is sent from the brain to other parts of the body via the bloodstream. Why do only certain cells respond to this signal?

		Hormones do not last long enough in the bloodstream to stimulate a cellular response
		Only cells that have a specific transcription factor gene will be able to respond to the signal
		Only cells in the immediate vicinity of the cell sending the signal will respond
		Only cells that have a receptor for the specific signal will be able to respond to it

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BIOL-242 Lecture Notes - Lecture 2: Adrenal Gland, Endocrine Gland, Parathyroid Gland

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