Endocrine System 18.1 to 18.3

What type of communication uses gap junctions to allow communication between adjacent cells?

Direct communication

Identify five mechanisms of intercellular communication

Direct, paracrine, autocrine, endocrine, and synaptic

The biogenic amine hormones include _______________________________

E, NE, dopamine, melatonin, and thyroid hormones

Describe negative feedback as it relates to humoral stimuli

Humoral stimuli are those involving changes in the composition of the extracellular fluid. This stimulus triggers the secretion of a hormone and the direct or indirect effects of the hormone reduce the intensity of the stimulus

An abnormally low production of gonadotropin produces a condition called

Hypogonadism

What primary factor determines each cell's hormonal sensitivities?

A cell's hormonal sensitivities are determined by the presence or absence of extracellular and intercellular receptors that bind a given hormone

Define hormone

A hormone is a chemical messenger that is secreted by one cell and travels through the bloodstream to affect the activities of cells in other parts of the body

Which hormones secreted by the adenohypophysis simulates the release of hormones by the adrenal cortex?

Adrenocorticotropic hormone

What is meant by the term second messenger in endocrine communication?

An intermediary molecule produced by hormone and receptor interaction

Identify the two lobes of the pituitary gland

Anterior lobe and posterior lobe

Which pituitary hormone causes a decrease in the amount of water lost in the kidneys?

Antidiuretic hormone

What hormones are released from the posterior lobe of the pituitary gland? And how does their release differ from hormones released by the anterior lobe?

Antidiuretic hormone (ADH) and oxytocin (OXT) Posterior pituitary hormones are released directly from the hypothalamus. While regulatory hormones from the hypothalamus control the release of anterior pituitary hormones

How would the presence of a substance that inhibits the enzyme adenylate cyclase affect the activity of a hormone that produces its cellular effects by way of the second messenger cAMP?

Any substance that inhibits adenylate cyclase would block the action of any hormone that requires cAMP as a second messenger This is because adenylate cyclase is the enzyme that converts ATP to cAMP

Response patterns in the endocrine system are particularly effective in __________________

Coordinating cell tissue and organ activities on a sustained long-term basis

What is an important second messenger produced by hormonal effects on a target cell?

Cyclic AMP

The release of which pituitary hormone would lead to an increased level of somatomedins in the blood?

Growth hormone

Which pituitary hormone causes liver cells to release somatomedins that increase the rate of uptake of amino acids by cells such as skeletal muscle fibers?

Growth hormone

In a typical regulation pattern of endocrine secretion, which hormone is responsible for negative feedback?

Hormone 2 (which is released from target organ) is responsible for negative feedback

Often, when brains are removed from the body and examined in dissection, the pituitary gland is missing. This is likely because it is encased in which bony structure?

Sella turcica

If a person were dehydrated, how would the amount of ADH released by the posterior pituitary lobe change?

In dehydration, blood osmotic concentration is increased which stimulates posterior lobe to release more ADH

What is the slender, funnel-shaped structure that connects the pituitary gland to the hypothalamus?

Infundibulum

Why is the hypothalamus a major coordinating and control center?

It contains autonomic centers and acts as an endocrine organ

What effect would an elevated circulating level of cortisol have on the pituitary secretion of ACTH?

It would inhibit the endocrine cells that control the release of ACTH from the pituitary gland so the ACTH levels would decrease Example of negative feedback

In what category are the eicosanoids, based on chemical structure?

Lipid derivatives

Which of the following hormones is secreted in the pituitary gland and controls melanin production during fetal development, in young children, in pregnant women, and in some disease states?

Melanocyte-stimulating hormone

The release of hormones by endocrine cells alters the _____________________

Metabolic activities of many tissues and organs simultaneously

What is another name for the posterior lobe of the pituitary?

Neurohypophysis

Describe paracrine communication

Paracrine communication is the use of chemical messengers (paracrines) to transfer information from cell to cell within a single tissue

The hypothalamus secretes regulatory hormones that directly affect what gland?

Pituitary gland

What hormone doesn't bind to receptors on the plasma membrane but to intracellular receptors in the cytoplasm or nucleus?

Steroid hormones

Which type of communication is involved in short-lived communication and crisis management?

Synaptic communication

A hormone that stimulates the opening of calcium channels and interaction with calmodulin ____________________

will trigger the activation of cytoplasmic enzymes