BI459 Lecture Notes - Lecture 4: Extracellular Fluid, Codocyte, Negative Feedback

76 views5 pages

silverbutterfly124

18 Apr 2017

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

It may be metabolized and/or excreted before or after it binds to a target cell. Liver and kidney major sites for metabolism and excretion. Synthesis and secretion of the hormone: e. g. , positive and negative feedback mechanisms seasonal/daily cycles, age and stage of development, sleep, etc. Delivery of hormone to target cell: regulating concentration of h in blood and extracellular fluid, how much blood directly effects how much and how quickly a hormone reaches a target. Binding to receptors on target cell: number and type of receptors on target cells. Termination of the response: less hormone secreted will decrease effect, no more hormone, no more effect essentially. Positive feedback loops: increase in hormone levels stimulates further secretion: important for short-term events or rapid response but is detrimental over longer time periods. Negative feedback loops: increase in hormone levels has an inhibitory effect on release or synthesis of the hormone: helps maintain homeostasis, contributes to pulsatile secretion of hormones.

Related Questions

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

Need help with biology questions:

1. To increase the excretion of an acidic drug, what would you do to the urine?

	A.	Make it more basic
	B.	None of the above
	C.	Make it neutral
	D.	Make it more acidic

2. G-Protein coupled receptors directly act on which of the following secondary messenger molecules:

	A.	cAMP
	B.	ATP
	C.	ADP
	D.	GTP
	E.	None of the above or more than one of the above

3. Drug A and Drug B both produce the same level of biological/physiological response. Drug A produces this effect with 100 mg/kg dose. Drug B produces this effect with 50 mg/kg dose. Which of the following is true?:

	A.	Drug B is more efficacious than Drug A. Both drugs are equally potent.
	B.	Drug A is more efficacious than Drug B. Both drugs are equally potent.
	C.	Drug A and B are equally efficacious. Drug A is more potent than Drug B.
	D.	Drug A and B are equally efficacious. Drug B is more potent than Drug A.

4. The stomach has a ______ pH, whereas the small intestines have a _______ pH. The colon has an approximately ___________ pH.

	A.	High; low; neutral
	B.	Low; high; neutral
	C.	Low; neutral; neutral
	D.	None of the above

5. Which receptor is most likely to reduce norepinephrine levels when activated?

	A.	alpha 2 adrenergic
	B.	alpha 1 adrenergic
	C.	dopamine D1 receptors

6. Which of the following statements are FALSE?

	A.	If the Vd of a drug is between 60 and 80 L the drug has likely distributed to the total body water of a 200 kg man.
	B.	In the enterohepatic system the activity of bacteria to remove conjugates from a drug in the gut will decrease the clearance of the drug.
	C.	Lipid drugs are more likely to be reabsorbed by the kidney from the urine.
	D.	A weak basic drug (pKa = 6) will be mostly ionized in urine of a pH= 3 and only the non- ionized drug will be eliminated.
	E.	The major conjugate in Phase 2 metabolism is glucuronide.

7. Isoproterenol (Î²-agonist) is a vasodilator that increases HR. What happens to systolic and diastolic pressures upon IV administration of isoproterenol?

	A.	â systolic; â diastolic
	B.	â systolic; â diastolic
	C.	â systolic; â diastolic
	D.	â systolic; â diastolic
	E.	None of the above

8. If you want to increase the blood concentration of a drug A, you can perform which of the following procedures:

	A.	Inhibit Drug A metabolism with Drug B
	B.	Enhance Drug A reabsorption from renal proximal tubule by changing ionization of Drug A with Drug B
	C.	Allow competition of Drug B with Drug A for active renal secretion processes
	D.	Increase the binding of Drug A to serum albumin
	E.	All of the above

9. Which of the following describes Phase I metabolism?

	A.	Inactive products are always produced in this phase.
	B.	Large molecules such as glucuronic acid are conjugated to drugs in this phase.
	C.	This phase may produce active metabolites from prodrugs.
	D.	This phase only occurs in the liver.

10. Which of the following is NOT an enzyme involved in the biosynthesis of biogenic amines?

	A.	Phenylethanolamine N-methyl Transferase
	B.	Dopamine Î²-hydroxylase
	C.	Tyrosine dehydroxylase
	D.	DOPA decarboxylase
	E.	All of the above

11. Why would an antibiotic at the same concentration be more active against bacteria in water than in serum or plasma? (Activity is measured in a test tube)

	A.	activity of the antibiotic is increased in water.
	B.	due to drug-protein interaction in serum
	C.	the antibiotic is more stable in water
	D.	all of the above
	E.	none of the above

12. Ion channels are targets for drugs. Which drug class targets Na+ channels?

	A.	Benzodiazepines
	B.	Beta blockers
	C.	Local anesthetics
	D.	Antihypertensive drugs (cardiac and smooth muscle)
	E.	Glibenclimide (diabetic drug)

13. _________________ not metabolized by catechol-O-methyltransferase (COMT).

	A.	Dopamine
	B.	Epinephrine
	C.	Phenylephrine
	D.	Norepinephrine
	E.	All of the above are metabolized by COMT.

BI459 Lecture Notes - Lecture 4: Extracellular Fluid, Codocyte, Negative Feedback

Document Summary

Get access

Related Documents

BI459 Lecture Notes - Lecture 6: Thyroid Peroxidase, Thyroid, Deiodinase

BI459 Lecture Notes - Lecture 10: Centroacinar Cell, Pancreatic Duct, Parotid Gland

BI459- Midterm Exam Guide - Comprehensive Notes for the exam ( 50 pages long!)

Related Questions