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Secretes chemicals that reach their target cells through the blood stream

The Endocrine System


What type of chemical messenger stimulates the cell that originally secreted it


What type of chemical messenger will act locally on nearby cells


What type of chemical messenger is realeased from neurons to activate an adjacent cell

The presence of a receptor specific for that hormone

What is it about a cell that identifies it as a target cell for hormones

They bind to interact with a receptor on or in the target cell

What do all hormones have in common

Slower and more prolonged

The general, the response of target cells to endocrine stimulation is _______ that their response to nervous stimulation

Help coordinate growth, development, and reproduction

Hormones are intercellular chemical signals that _________


Most endocrine glands communicate with their target tissues using _____ signals


An intercellular chemical signal that is produced by neurons but functions like a hormone would be called a _______

Polypeptides, steroids, and proteins

What organic molecules include hormones?


Which chemical type of hormone has a longer half-life


Which chemical class of hormone is more likely to need a binding protein for transport in the blood?


Members of which group of hormones are made from cholesterol?

The rate at which hormones are eliminated from the body

What does the half-life of a hormone allow one to determine?

Regulate activities of rapid onset and short duration

What do hormones with short half-lives do?

By the presence of specific receptor molecules on the target cells

How do hormones and target cells recognize one another?

As free hormones

How do most water-soluble hormones travel through the bloodstream?

Chronic Hormone Secretion

Which pattern of hormone secretion, exemplified by thyroid hormones, remains relatively constant over long periods of time?

Episodic Hormone Secretion

Which pattern of hormone secretion, often observed in steroid reproductive hormones, will fluctuate over a monthly cycle?

Acute Hormone Secretion

Which pattern of hormone secretion, represented by epinephrine, can have dramatic changes in its concentration and circulating levels?

Chronic and Episodic Hormone Secretion

In general, lipid-soluble hormones exhibit which types of hormone secretion patterns?

Action of a substance other than a hormone, the nervous system, and other hormones

What can hormonal secretion be regulated by?


Secretion of one hormone by the action of another hormone is controlled by _____ stimuli


Parathyroid hormone is released when blood calcium levels decrease, this is an example of control by _____ stimuli


Most hormones are regulated by _______ feedback mechanisms


In some forms of diabetes, an insensitivity to insulin seems to be present. This insensitivity could be the result of ________

Produces an increase in the sensitivity of the target cell to the hormone

What does Up-Regulation do?

Increased in number or decreased in number

Hormone receptor molecules may be ____ in order to change the target cell's sensitivity to a given hormone

On the plasma membrane of their target cells

Where are receptors for most water-soluble hormones located?

In the nucleus or cytoplasm of their target cells

Where are receptors for most lipid-soluble hormones located?

G protein

What is a regulatory protein associated with membrane-bound receptor molecules?

1) G Protein subunits bind to receptor
2) GTP binds to the alpha subunit replacing GDP
3) G Protein subunits separate from the receptor
4)Alpha subunit separates from the other two subunits
5) Alpha subunit-GTP complex alters cell activity

Name the events that occur when a water-soluble hormone binds to its receptor on the plasma membrane

Bind to and activate protein Kinase

What is the role of cAMP when it acts as an intracellular mediator in cells?

Cyclic GMP might be produced to act as an intracellular mediator

When a hormone binds to a membrane-bound receptor.....

Ion channels could be opened, IP3 may be activated, cyclic AMP production may be increased, DAG may be activated

What could happen when a hormone binds to a membrane-bound receptor and activated G Proteins?

To inactivate cyclic AMP

What does Phosphodiesterase function to do?

A cascade effect

The activation of a single G Protein results in the activation of several second messengers. This process is known as _______

Activation of mRNA synthesis (transcription)

What occurs when a hormone binds to a nuclear receptor?


What type of hormone diffuses easily through the plasma membrane?

Hormone receptor complex binds to DNA
Hormone binds to receptors in the nucleus (sometimes cytoplasm)
Messenger RNA synthesis is activated

Events in the nuclear receptor model


A chemical that is produced by a neuron that functions as a hormone is a _____


A chemical that is secreted into the blood by specialized cells; travels some distance to target tissues


A chemical that is secreted by presynaptic terminal

Nuclear Receptor Model

What receptor model is used by most lipid-soluble hormones?

Membrane-Bound Receptor Model

What receptor model is an intracellular mediator?

Membrane-Bound Receptor Model

What receptor model is a G Protein?

Nuclear Receptor Model

What receptor model interacts with DNA?

Membrane-Bound Receptor Model

What receptor model is cyclic AMP or cyclic GMP involved?

Nuclear Receptor Model

What receptor model generally observes a latent period?

Nuclear Receptor Model

What receptor model is messenger RNA synthesis regulated?

Membrane-Bound Receptor Model

What receptor model has membrane channels that can be opened or closed?

Target Tissues

Hormones that act on specific tissues/cells are called _______

Paracrine Chemical Messengers

What chemical signals are released by cells and affect other cell type locally w/o being transported in blood?


Increasing levels of thyroid hormones decrease TSH levels. This is an example of _____ feedback.


The length of time needed to eliminate half a dose of a hormone is called its ______

Regulating skeletal muscle contraction and strength

What is NOT a regulatory function of the endocrine system?

Regulating equilibrium and balance from the inner ear

What is NOT a regulatory function of the endocrine system?


What regulates the secretory activity of the pituitary gland?


What is the connecting stalk between the hypothalamus and pituitary gland?

Neurohypophysis and Adenohypophysis

What are the two functional portions of the pituitary gland?


The ____ pituitary has a direct connection with neurons of the hypothalamus

Hypothalamus to anterior pituitary

Where does the hypothalamohypophysial portal system carry hormones to?

Hypothalamus to the posterior pituitary

The hypothalamohypophysial tract carries neurons from the _____ to the _____

Posterior pituitary

What does the hypothalamohypophysial tract connect the hypothalamus to?


Hormone secretion by the anterior pituitary is controlled by _____ of the hypothalamus

Carry action potentials to the posterior pituitary causing the release of oxytocin

A function of the hypothalamohypophysial tract is to.....

Increase anterior pituitary secretion

What do releasing hormones do?

Action potentials from hypothalamic neurons

Hormones are released from the posterior pituitary when posterior pituitary cells are stimulated by what?

Construction of blood vessels

ADH is also called vasopressin because at high concentrations it causes what?

High solute of concentration within the body fluids

ADH is secreted in response to what?

The kidney tubules to retain more water

What will an increase of ADH secretion cause?

Decreased BP, increased ADH secretion, and decreased urine volume

What results in a decrease in blood volume?


What hormone is sometimes given to women to induce labor?


What hormone is synthesized by the hypothalamus?

ADH secretion decreases

What happens if fluid intake increases dramatically over a short time frame?

Blood volume decreases and blood pressure decreases

ADH secretion will increase if ______


Sweating causes water loss from the body. In creased water loss causes the blood solute concentration to increase. What "senses" this increase?


Urine volume ______ when ADH secretion decreases


What hormone is stored and released from the posterior pituitary?


What hormone is responsible for causing contractions in smooth muscle during labor?

Nursing a baby

Oxytocin release is stimulated by what?


What hormone is secreted by the anterior pituitary?


What is ADH is synthesized by?

Anterior pituitary

What is TSH synthesized by?

Pituitary (hypophysis)

Which gland is located in the sella turcica (pituitary fossa)?

Growth Hormone

What hormone increases water reabsorption from the kidneys?

Growth Hormone-Inhibiting Hormone

What hormone inhibits the secretion of growth hormone?


What hormone stimulates the development of follicles in the ovary?


What hormone is required for ovulation and formation of the corpus luteum?


Synthesis of progesterone in the ovary and testosterone in the testis is stimulated by what hormone?

Thyroid Gland

If you removed the anterior pituitary what would it affect the functioning of?


GnRH regulates the release of what hormones?


Osmoreceptor cells in the hypothalamus are involved in the secretion of what hormone?

Thyroid hormone

Hypersecretion of what hormone causes increased metabolic rate, sensitivity to heat, and weight loss?


Which ion is necessary for thyroid hormone production?


T3 & T4 are stored in the lumen of thyroid follicles as part of the ____ molecule

Thyroxine-Binding Globulin (TBG)

What are most T3 & T4 molecules bound to in the blood?

Binding to receptor molecules in the nucleus

How does a thyroid hormone interact with its target tissue?

High to increase body temperature

John Smith works at a ski resort in the winter. What are his thyroid hormone levels like in the winter?


Increased metabolic activity and weight loss are associated with what?

Weight gain

What is associated with hyposecretion of thyroid hormones?

TSH from the anterior pituitary

What hormone is involved in the regulation of thyroid hormone levels?


What is a target tissue for parathyroid hormone?

Blood calcium levels decrease

The rate of secretion of parathyroid hormone increases when what happens?

Decreases the release of phosphate from the bone

What is NOT an action of PTH?


What hormone allows kidneys to retain calcium?

Cardiac arrhythmias occur

What happens with hypocalcemia?

Accidental removal of the parathyroid glands during surgery

After surgery of removing an aggressive tumor of the thyroid, the patient's blood calcium levels began declining to life-threatening levels. What is the decline most likely due to?

Adrenal glands

What are the endocrine glands located on top of the kidneys?


What hormone is NOT secreted by the adrenal cortex?

Adrenal Medulla

What plays a role in the adaptation of the body for physical activity?

Blood pressure

Epinephrine increase what?

Increase heart rate, increase BP, and decrease gastric tract motility

What would an injection on epinephrine do to the body?

Sympathetic nervous system

Where does the primary stimulus for release of adrenal medullary hormones come from?


What is the major secretory product of the zona glomerulosa of the adrenal cortex?


What hormone does the adrenal cortex of the adrenal gland secrete?

Increased plasma levels of cortisol

What will decrease glucocorticoid (cortisol) secretion by the adrenal cortex?

Depression of the immune response

What might be the result of hypersecretion of glucocorticoids?

High cortisol levels will begin to cause ACTH levels to decline

What would occur if both ACTH and cortisol levels increase?

Adrenal androgens

What stimulates the growth of public hair in females?

Hyposecretion of mineralocorticoids (aldosterone)

What condition could result in polyuria (excess urine)


What gland is both an endocrine gland and en exocrine gland?

Increase the uptake of glucose by its target tissues

What is a function of insulin?


High blood glucose levels cause an increased secretion of what?

Gamma cells

What is NOT a type of cell found in the pancreas?


What do alpha cells secrete?

Islets of Langerhans (Pancreatic Islets)

Both glucagon and insulin are produced in the ______

Insulin secretion decreases; glucagon secretion increases

What happens when blood sugar levels decrease?

They feel intensely hungry

What happens to a person when their insulin levels low?


Glucagon primarily influences the cells of the ____

Glycogen Synthesis

Increased insulin secretion immediately following a meal will result in increased _____

Breakdown of glycogen in the liver releasing glucose

What helps to keep blood nutrients at normal levels 6-8 hrs after a meal?


A person with insulin-dependent diabetes mellitus (IDDM) forgets to take their insulin, what does this cause?

Increased epinephrine and glucagon release

During exercise, the energy needed to sustain skeletal muscle cell contraction comes from what?


What gland does NOT produce reproductive hormones?

Photoperiod (daily amount of daylight)

What regulates the amount of melatonin secreted by the pineal body?

Development and maturation of the immune system

What is the function of thymosin?


The amount of water reabsorbed by the kidney when ADH is present is (greater, lesser, or equal) than the amount of water reabsorbed by the kidney when ADH is absent


The level of ACTH during stress is (greater, lesser, or equal) than the level of ACTH during relaxation


The metabolic rate if thyroid hormones are under secreted (greater, lesser, or equal) than the metabolic rate if thyroid hormones are over secreted


The blood calcium levels if parathyroid secretion decreases (greater, lesser, or equal) than the blood calcium levels if parathyroid hormone secretion increases


What hormone decreases blood calcium levels?


What hormone stimulates synthesis of thyroid hormones?


What hormone increases adrenal cortex secretions?


What hormone is involved in milk production?


What hormone is involved in the development of the immune system?


What gland secretes the hormone glucagon?


What gland secretes the hormone progesterone?

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