Pathophysiology Exam #4 Endocrine System

Hormones produce their effects through binding to ____________, which in turn are linked to one or more effector systems within the cell.

High-affinity receptors

Hormones

Highly specialized organic molecules produced by endocrine organs that exert their action on specific target cells

Paracrine

Hormone acts on cell that produced it

When hormones act locally on cells other than those that produced the hormone, the action is called ______.

paracrine

The structure of hormone _____ varies in a manner that allows target cells to respond to one hormone and not to others.

receptors

In an adult with acromegaly, a growth hormone (GH)-secreting tumor is suspected. What diagnostic test would be used for this client?

A GH suppression test may be used to confirm this situation.

Hormones can be synthesized by both vesicle-mediated pathways and non-vesicle-mediated pathways. What hormones are synthesized by non-vesicle-mediated pathways?

Androgens and estrogens. Hormones that are synthesized by non-vesicle-mediated pathways include the glucocorticoids, androgens, estrogens, and mineralcorticoids - all steroids derived from cholesterol.

When hormones act locally rather than being secreted into the bloodstream, their actions are termed what?

Autocrine and paracrine. When hormones act locally on cells other than those that produced the hormone, the action is called paracrine. Hormones also can exert an autocrine action on the cells from which they were produced.

Describe the concept of a "hormone."

Hormones are generally thought of as chemical messengers that are transported in body fluids. They are highly specialized organic molecules produced by endocrine organs that exert their action on specific target cells. Hormones do not initiate reactions but function as modulators of cellular and systemic responses. Most hormones are present in body fluids at all times, but in greater or lesser amounts depending on the needs of the body.

Second messenger

Intracellular signal

____________ hormones attach to intracellular receptors and form a hormone-receptor complex that travels to the cell nucleus to initiate transcription.

Lipid-soluble

The hormone levels in the body need to be kept within an appropriate range. How is this accomplished for many of the hormones in the body?

Negative feedback loop. The level of many of the hormones in the body is regulated by negative feedback mechanisms.

The functions of the endocrine system are closely linked with those of the ___________________ system, but the response time is much more slower, but longer lasting.

Nervous

Many hormones are measured for diagnostic reasons by using the plasma levels of the hormones. What is used today to measure plasma hormone levels?

Radioimmunoassay methods. Real progress in measuring plasma hormone levels came up more than 40 years ago with the use of competitive binding and the development of radioimmunoassay methods.

Hypophysis

The hypothalamus and the pituitary

Imaging has proven useful in both the diagnosis and follow-up of endocrine disorders. Two types of imaging studies are useful when dealing with endocrine disorders, Isotopic imaging and nonisotopic imaging. What is an example of isotopic imaging?

Thyroid scan. Isotopic imaging includes radioactive scanning of the thyroid.

The endocrine system uses chemical substances called ____________________ as a means of regulating and integrating body functions.

hormones

Hormone response element

Activate or suppress intracellular mechanisms such as gene activity.

__________________ defects result in endocrine hypofunction due to the absence or impaired development of the gland or the absence of an enzyme needed for hormone synthesis.

Congenital

_______________ is a term used to describe children (particularly boys) who have moderately short stature, thin build, delayed skeletal and sexual maturation, and absence of other causes of decreased growth.

Constitutional short stature

The term __________ is used to describe a child who is taller than his or her peers and is growing at a velocity that is within the normal range for bone age.

Constitutional tall stature

Hormones that are released into the bloodstream circulate either as _________________ molecules or as hormones _____________ to transport carriers.

Free, bound

Several hormones are essential for normal body______________ and maturation, including growth hormone (GH), insulin, thyroid hormone, and androgens

Growth

Disturbances of endocrine function usually can be divided into two categories : ________________ characterized by decreased action, __________ characterized by increased hormonal action.

Hypofunction, hyperfunction

The hypophysis is a unit formed by the pituitary and the hypothalamus. These two glands are connected by the blood flow in what system?

Hypophyseal portal system. The hypothalamus and the pituitary (i.e. hypophysis) form a unit that exerts control over many functions of several endocrine glands as well as a wide range of other physiologic functions. These two structures are connected by blood flow in the hypophyseal portal system, which begins in the hypothalamus and drains into the anterior pituitary gland, and by the nerve axons that connect the supraoptic and paraventricular nuclei of the hypothalamus with the posterior pituitary gland.

Growth hormone cannot directly produce bone growth; instead, it acts indirectly by causing the liver to produce ___________________.

Insulin-like growth factors

The easiest way to measure hormone levels during a specific period are by either blood samples or urine tests to measure ____________ or ______________.

Metabolites, hormone levels

Sometimes the measurement of hormones is done through a urine sample. What is an advantage of measuring hormone levels through a urine sample rather than a blood sample?

The advantages of a Urine test include the relative ease of obtaining urine samples and the fact that blood sampling is not required.

To prevent the accumulation of hormones in our bodies, the hormones are constantly being metabolized and excreted. Where are adrenal and gonadal steroids hormones excreted?

Unbound adrenal and gonadal steroid hormones are conjugated in the liver, which renders them inactive, and then excreted in the bile and urine.

The pituitary gland has been called the ___________ because its hormones control the functions of many target glands and cells.

master gland

The endocrine system is closely linked with the Nervous system. What neurotransmitter can also act as a hormone?

epinephrine

The synthesis and release of anterior pituitary hormones is regulated by the action of releasing or inhibiting hormones from the ______________, which is the coordinating center of the brain for endocrine, behavioral, and autonomic nervous system function.

hypothalamus

_________________ secretion is stimulated by hypoglycemia, fasting starvation, increase blood levels of amino acids, and stress conditions such as trauma, excitement, emotional stress, and heavy exercise as a way to compensate for the increased stress.

Growth hormone

Autocrine

Hormone affecting neighboring cells

Half-life of a hormone

Time it takes for the body to reduce the concentration of the hormone by one-half

Hormones also can exert an ____________ action on the cells from which they were produced.

autocrine