Module 6.1: Endocrine Disorders

negative feedback mechanism

-A negative feedback mechanism regulates the endocrine system by inhibiting hormone overproduction

Hormones

-Chemical messengers that interact with receptors at distant target sites. -act locally to incite local effects -present in body fluids at all times in greater or lesser amounts as needed -A single hormone can influence multiple tissues -A single function can be regulated by multiple hormones.

Feedback Mechanism

-Hormone levels are regulated by feedback mechanisms that function similarly to a thermostat. -Hormone levels from the target glands regulate the release of hormones from the anterior pituitary through a negative feedback system. -When a decrease in hormone levels is detected, sensors initiate changes that cause an increase in hormone production.

A patient suspected of having primary hypothyroidism would have a serum laboratory report that reveals which findings? Decreased thyroid-stimulating hormone (TSH) related to poor thyroid function Elevated TSH, triiodothyronine (T3), and thyroxine (T4) Elevated TSH and decreased T4 Decreased TSH and T4, and low T3

:Elevated TSH and decreased T4 A patient with primary hypothyroidism would have elevated TSH and low levels of T3, T4, and free T4 because of dysfunction in only the thyroid gland.

Posterior Pituitary

An extension of the hypothalamus with neural pathways connecting the hypothalamus to the posterior pituitary gland. these effector hormones are produced in the hypothalamus but are stored in the posterior pituitary: -Antidirutic hormone (ADH) -Oxytocin

Which best defines a hormone? Chemical messenger that controls the flow of information among the different tissues and organs of the body A small, nonproteinaceous substance that is not antigenic by itself but can act as an antigen when combined with a larger molecule Any one of a group of small glycoproteins Any chemical or physical agent that induces unusual change in form

Chemical messenger that controls the flow of information among the different tissues and organs of the body

Endocrine Disorders originate in ..

Hypothalamus, pituitary glands, or target glands.

Adrenal gland

Produces steroids, amines, epinephrine, and norepinephrine. The adrenal cortex secretes three types of hormones: 1. mineralocorticocoids 2. Glucocorticoids 3. Androgens and estrogens

Positive feedback mechanism

Regulates a small number of hormones by causing a hormone to stimulate continued secretion until appropriate levels are reached.

Following destruction of the pituitary gland, adrenocorticotropic hormone (ACTH) stimulation stops. Without ACTH to stimulate the adrenal glands, the production of cortisol drops. This is an example of which type of endocrine disorder? Primary Secondary Tertiary Somatic

Secondary In secondary disorders of endocrine function, the target gland is essentially normal, but defective levels of stimulating hormones or releasing factors from the pituitary system alter its function.

A patient's lab results show low thyroid hormone levels and elevated cortisol levels. TSH and ACTH levels are also low. Which level of endocrine disorder does this illustrate?

Secondary -Because there are abnormal hormone levels from two different glands (thyroid and adrenal). Both the affected glands are controlled by the pituitary. A primary disorder would involve only one gland. A tertiary disorder would involve abnormal levels of hormones' produced from the hypothalamus and pituitary.

A patient experienced damage to the pituitary gland due to a tumor, and ACTH stimulation ceased. Without ATCH yo stimulate the adrenal glands, production of cortisol decreased. Which level of endocrine disorder does this illustrate? A. Primary B. Secondary C Tertiary

Secondary -because the pituitary gland is involved.

A client sustained head trauma and was in the hospital for 3 months before preparing for discharge. The only abnormalities in the final lab tests were low triiodothyronine (T3), thyroxine (T4), and cortisol levels. Further tests indicate hypothalamus damage from the accident. Which type of endocrine disorder would this indicate? Primary Secondary Tertiary Traumatic

Tertiary A tertiary endocrine disorder involves dysfunction in the gland, the pituitary, and the hypothalamus. Head trauma is the most common reason for hypothalamus injury. There is no indication of a primary or secondary cause.

A patient's lab work indicated low levels of cortisol, ACTH and ACTH-releasing hormone Which level of endocrine disorder does this illustarte?

Tertiary. -Because the levels of cortisol (from the gland), ACTJ (from the pituitary), and ACTH-releasing hormone (from the hypothalamus) are all low. If the gland hormone and pituitary gland hormone are elevated or decreased, and the hypothalamus releasing hormone is elevated, then it is a tertiary disorder.

Anterior Pituitary

The hypothalamus exerts hormonal control at the anterior pituitary gland by releasing or inhibiting hormones. Hypothalamic hormones stimulate the anterior pituitary gland to release four types of of trophic (Gland stimulating) hormones: ACTH, TSH, LH, FSH, growth hormone, and prolactin

How can a secondary disorder of endocrine function be best described? They occur in the target gland responsible for producing the hormone. The target organ is normal, but its function is altered by stimulating hormones. They come from the target organ before it becomes dysfunctional. They occur from the hypothalamic dysfunction that causes understimulation of the target organ.

The target organ is normal, but its function is altered by stimulating hormones. In secondary disorders of endocrine function, the target gland is essentially normal, but its function is altered by defective levels of stimulating hormones or releasing factors from the pituitary system.

Which is the best definition of primary endocrine disorders? They originate in the target gland responsible for producing the hormone The target gland is essentially normal, but its function is altered by defective levels of stimulating hormones. The target gland is essentially normal, but its function is altered by defective levels of releasing hormones from the pituitary. They result from hypothalamic dysfunction, so both the pituitary and target glands are understimulated.

They originate in the target gland responsible for producing the hormone

Thyroid

Thyroid hormones are necessary for normal growth and development. They also act on many tissues by increasing metabolic activity and protein synthesis. -Thyroxine (T4), Triiodothyronine (T3)

Hypothalamus

brain region controlling the pituitary gland

Types of endocrine disorders

hyposecretion, hypersecretion, hyporesponsiveness, hyperresponsiveness 1. Primary: Results when there is a dysfunction of a target gland 2. Secondary: result when a target gland is healthy, but its function is altered by defective levels of stimulating hormones or releasing factors from the pituitary gland 3. tertiary: Results from hypothalamic dysfunction, or understimulation of pituitary and target organs.

The endocrine system

regulates metabolism and maintains homeostasis

Guidelines to determine endocrine disorders

see picture