Human Anatomy and Physiology : Systems Physiology

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

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Example Question #1 : Systems Physiology

How do steroid hormones affect their target organs?

Possible Answers:

They bind to receptors on the cell membrane in order to be activated, allowing them to directly enter the cell

They travel to target organs by floating freely in the bloodstream

They attach to protein receptors on the cell membrane

They enter the nucleus and affect the transcription of genes

They use a second messenger system to elicit an effect on target cells

Correct answer:

They enter the nucleus and affect the transcription of genes

Explanation:

Steroid hormones are nonpolar hormones that require carrier proteins in order to travel through the bloodstream. Once they reach their target cell, they are able to enter the cell's nucleus and affect the transcription of certain genes. Since steroid hormones are derived from cholesterol they are small and nonpolar, allowing them to freely diffuse across the membrane without protein mediation.

In contrast, peptide hormones and tyrosine derivatives are unable to freely cross the membrane due to size. Since these hormones cannot directly enter the cell, they generally initiate second messenger signal cascades. Peptide hormones are able to freely circulate, while tyrosine derivatives bind to carrier proteins in the blood.

Example Question #1 : Endocrine Physiology

Which of the following is a steroid hormone?

Possible Answers:

Cortisol

Parathyroid hormone

Insulin

Epinephrine

Correct answer:

Cortisol

Explanation:

Cortisol is the only steroid hormone listed, some other examples would be estrogen and androgens. Insulin and parathyroid hormones are peptide hormones. Epinephrine is a catecholamine, which is a tyrosine derivative.  

Example Question #1 : Systems Physiology

Which of the following is not a steroid hormone? 

Possible Answers:

Cortisol 

Androgen 

Aldosterone 

Estrogen 

Thyroid-stimulating hormone 

Correct answer:

Thyroid-stimulating hormone 

Explanation:

Estrogen, androgen, progesterone, cortisol, and aldosterone are all steroid hormones. Thyroid-stimulating hormone belongs to the class of hormones that are proteins, glycoproteins, and peptide hormones. Specifically, thyroid-stimulating hormone is a glycoprotein. 

Example Question #1 : Systems Physiology

Prostaglandins belong to what class of hormones? 

Possible Answers:

Retinoids 

Steroids 

Amines 

Eicosanoids 

Proteins 

Correct answer:

Eicosanoids 

Explanation:

Eicosanoids are local paracrine and autocrine agents that play an important role in inflammation. The eicosanoids include the thromboxanes, lipoxins, leukotrienes, and the prostaglandins. 

Example Question #1 : Systems Physiology

Which of the following is not an example of a lipid-soluble hormone? 

Possible Answers:

Thyroid hormones 

Insulin

Cortisol

Estrogen 

Prostaglandins 

Correct answer:

Insulin

Explanation:

Insulin belongs to the "proteins and peptides" class of hormones. The proteins and peptides are water-soluble hormones. Thyroid hormones, all steroids, retinoids, prostaglandins and vitamin D are all examples of lipid-soluble hormones. Note that even though thyroid hormones are derived from the amino acid tyrosine, they are insoluble in water, and are carried in the blood by proteins.

Example Question #6 : Systems Physiology

A particular hormone attaches to a receptor on its target organ and causes a secondary hormone signaling pathway to begin. What type of hormone is it?

Possible Answers:

Initiation

Tropic

Hydrophobic

Direct

Hydrophilic

Correct answer:

Tropic

Explanation:

A direct hormone binds to its target organ and effects an immediate change. A tropic hormone causes a secondary messenger pathway to commence and effects a change at the end of the pathway resulting in the release of another hormone. Hydrophobic hormones refer to lipophilic molecules, while hydrophilic molecules are the opposite. An example of this is adrenocorticotropic hormone (ACTH) released from the anterior pituitary. It's target is the adrenal cortex, and its action is to stimulate the adrenal cortex to release cortical hormones.

Example Question #1 : Help With Hormone Origins And Targets

Which of the following allows peptide hormones to initiate their effect on target cells?

Possible Answers:

They attach to receptors in the cytosol

They attach to membrane receptors on the target cell

They attach to the DNA in the nucleus

They attach to carrier proteins in the bloodstream

Correct answer:

They attach to membrane receptors on the target cell

Explanation:

Peptide hormones are large polar hormones that are able to freely float in the bloodstream. Once they reach their target cells, peptide hormones attach to transmembrane receptors on the target cell. This generally initiates a second messenger signal cascade to amplify the response, eventually driving a change in genetic expression and transcription.

In contrast, steroid hormones are small and nonpolar. These characteristics allow them to freely diffuse across the plasma membrane of the cell and enter the nucleus, where they can directly act as transcription factors to regulate genetic expression.

Example Question #2 : Help With Hormone Origins And Targets

Hypersecretion of the growth hormone during adulthood results in which of the following?

Possible Answers:

Gigantism, where the individual develops abnormal body and facial proportions in relation to his or her size

Acromegaly, where the individual develops abnormal body and facial proportions in relation to his or her size

Dwarfism, where the individual develops normal body and facial proportions in relation to his or her size

Acromegaly, where the individual develops normal body and facial proportions in relation to his or her size

Gigantism, where the individual develops normal body and facial proportions in relation to his or her size

Correct answer:

Acromegaly, where the individual develops abnormal body and facial proportions in relation to his or her size

Explanation:

Hypersecretion, or oversecretion, of the growth hormone in adulthood results in a condition called acromegaly. The adult individual no longer has growth plates at this point, so the excess hormones interact with the receptors on the surface of bones. This results in coarse facial features, thickening of the dermis, and large hands and feet. 

Gigantism is also a result from hypersecretion of the growth hormone, but it occurs during childhood when the individual still has his or her growth plates. Dwarfism is a result from hyposecretion, or undersecretion, of the growth hormone. 

Example Question #1 : Endocrine And Reproductive Physiology

What is the primary target for gastrin?

Possible Answers:

Gonads

Bone

Gastrointestinal tract and pancreas

Kidneys

Correct answer:

Gastrointestinal tract and pancreas

Explanation:

Gastrin is a hormone secreted by the stomach and small intestine that acts on the gastrointestinal tract and pancreas. Many hormones, such as vasopressin (antidiuretic hormone) and aldosterone act on the kidneys. Hormones that target bone are calcitonin and parathyroid hormone. Hormones that target gonads include follicle stimulating hormone and luteinizing hormone. 

Example Question #4 : Help With Hormone Origins And Targets

What hormone does the heart secrete?

Possible Answers:

Thymosin

Atrial natriuretic peptide

Androgens

Oxytocin

Correct answer:

Atrial natriuretic peptide

Explanation:

The heart secretes atrial natriuretic peptide, which acts on the kidneys. Oxytocin is secreted by the posterior pituitary. Thymosin is secreted by the thymus gland. Androgens are secreted by the adrenal cortex. 

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