Chapter 17: Endocrine System (A&P II)

Growth Hormone

- Affects most body cells - Stimulates cell growth and mitosis - Known as somatotropin - Is a tropic hormone Growth Hormone does NOT: stimulate the kidney to secrete somatomedin

Endocrine Glands

- Ductless glands - Organs of the endocrine system - Secrete hormones directly into the bloodstream - Help maintain homeostasis

The pancreas

- Is located posterior to the stomach, between the small intestine and the spleen - Heterocrine, or mixed, gland - Elongated in shape, spongy, and nodular - Majority of cells in the pancreas are pancreatic acini False statement about the pancreas: "it does not begin to secrete its hormones until puberty"

How does aging affect the endocrine system

- Secretory activity of endocrine glands decreases - Normal levels of hormones, particularly growth hormone and sex hormones, often decreases - Aging reduces the efficiency of endocrine system functions - Endocrine system imbalances can lead to weight gain or muscle loss

In which order would blood flow through these structures as it travels from the hypothalamus to the pituitary gland A - primary plexus B - secondary plexus C - hypophyseal portal veins

A C B

Excessive secretion of growth hormone in adults can cause

Acromegaly

Which lobe of the pituitary is larger and secretes more hormones

Anterior pituitary

Thyroid-stimulating hormone (TSH) is secreted by the

Anterior pituitary, and it targets follicular cells of the thyroid gland

The hormones that come from the posterior pituitary

Are synthesized in the hypothalamus and are released from the posterior pituitary when nerve signals arrive

During thyroid surgery, a surgeon mistakenly removes the parathyroid glands from his patient. What is the likely outcome of the patient

Blood calcium levels will drop

Aldosterone release can be triggered by the presence of the blood-borne messenger angiotensin II or by low levels of sodium, and so its secretion regulation is said to be

Both hormonal and humoral

The hypothalamic hormone that triggers the release of adrenocorticotropic hormone (ACTH) is

Corticotropin-releasing hormone (CRH)

Once a structure is fully grown and mature, it will probably

Down-regulate its receptors for growth hormone, as it no longer needs to continue to grow at a fast rate

In response to excessive amounts of hormone, a target cell may reduce its number of receptors for that hormone. This is an example of

Down-regulation

Intracellular signaling pathways within target cells are organized such that

Each step allows for amplification of the signal where one molecule can activate many

Characteristic of the endocrine system

Effects: causes metabolic activity changes in target cells Response time: slow reaction time = seconds to hours Duration of response: long-lasting = minutes to weeks Communication method: hormones in the bloodstream Not a Characteristic: Recovery time: rapid, immediate return to prestimulation level

Which is False

False: - Melatonin makes us feel alert and awake True: - The pineal gland forms part of the epithalamus - the pineal gland is found within the diencephalon of the brain - The pineal gland secretes melatonin in a cyclical fashion

The hormone that increases the rate of glycogen breakdown and glucose release by the liver is

Glucagon

Follicle-stimulating hormone is a

Glycoprotein

You are "shadowing" an endocrinologist who is examining a patient complaining of weakness, weight loss, and heat intolerance. The doctor points out the patient's obvious exophthalmos and asks for your diagnosis. What would you speculate is the patients problem

Hypersecretion of thyroid hormone

The part of the brain that functions as a "master control center" of the endocrine system is the

Hypothalamus

The thyroid gland is located

Immediately anterior to the trachea

Insulin causes a(n) ____ in glycogenesis in the liver and a(n) ___ in lipogenesis in adipose

Increase ; Increase

The pituitary gland is located ____ to the hypothalamus and is connected by the ___

Inferior ; Infundibulum

Which hormone induces its target cells to take up glucose, thereby lowering blood glucose levels

Insulin

Which hormone is secreted by the beta cells of the pancreas

Insulin

Which type of hormone requires a carrier protein in the blood

Lipid-soluble hormone

Which hormone is secreted by the pineal gland

Melatonin

As someone starts to develop in puberty, most cells in their reproductive organs are probably starting to express

More receptors for sex hormones

Where are the target cells for follicle-stimulating hormone?

Ovaries and testes

The two hormones released from the posterior pituitary are

Oxytocin and antidiuretic hormone

In addition to secreting hormones, the pancreas also produces

Pancreatic Juice

When a chemical messenger helps initiate an inflammatory response by causing cellular changes in neighboring cells, it is demonstrating ___ signaling.

Paracrine

In the signal transduction pathway that results in the formation of inositol triphosphate, the G protein directly activates

Phospholipase C

The pancreas is located ___ to the stomach, and it lies between the duodenum and the ___

Posterior ; Spleen

The adrenal glands are located ____ to the parietal peritoneum and each has a cortex of a ___ color

Posterior ; Yellow

Within the adenylate cyclase signal transduction pathways of target cells, cAMP activates

Protein kinase

Most hormones are made of chains of amino acids and are therefore

Proteins

Growth hormone is secreted by ___ cells in the anterior pituitary

Somatotropic

The primary function of adrenocorticotropic hormone (ACTH) is to

Stimulate glucocorticoid release from the adrenal glands

Growth hormone

Stimulates gluconeogenesis

The binding of a hormone and a carrier protein is ____ ; a very ____ fraction of such a hormone in the blood is bound to a carrier at any point in time

Temporary ; Large

When the effects of water-soluble hormones on their target cells are considered, the hormone itself is

The first messenger

Generally, the shorter the half-life of a hormone

The more frequently it must be replaced

The release of hormones from the adrenal medulla is stimulated by

The sympathetic division of the autonomic nervous system

The half-life of a hormone is

The time necessary to reduce the hormone concentration in the blood to half of what had been secreted

Thyroid hormone synthesis involves secretion of a glycoprotein called ___ by the follicular cells

Thyroglobulin

Reduced hormone concentration in the blood often causes target cells to

Up-regulate receptors in order to increase cell sensitivity

Protein hormones are

Water-soluble

Which region of the adrenal cortex synthesizes glucocorticoids

Zona Fasciculata