The endocrine system CH7&23 (copy) JR

Lack of iodine in your patient's diet could cause all of the following except:

increased metabolic rate and hyperexcitable reflexes

All of the following are characteristics of hormones except:

Hormones must bind to receptors embedded in the plasma membranes of target cells.

All of the following hormones directly result in an increased concentration of glucose in the blood except:

thyroid hormone

If the concentration of vasopressin in the blood is 12 ng/L and the half-life of vasopressin in the blood is 15 minutes, what will the concentration of vasopressin be in the blood after 30 minutes?

Note: assume no additional vasopressin is produced during this time.

3 ng/L

When cortisol is given as an immunosuppressant, it can decrease secretion of corticotropin releasing hormone (CRH) from the hypothalamus and ACTH from the pituitary gland. This is an example of:

long-loop negative feedback

Which hormone is most likely to reduce the concentration of calcium in the blood?

calcitonin

Which of the following is not a tropic hormone?

prolactin

The anterior pituitary gland is also called the---------and is composed primarily of--------------tissue.

adenohypohhysis; epithelial

The posterior pituitary gland receives input from the hypothalamus via--------------and can release-----------into the blood

action potentials sent along the axons of neurons; vasopressin

Assume the release of an imaginary hormone increases the concentration of glucose in the blood by 10 mg/dL.

Now assume the release of a different imaginary hormone increases the concentration of glucose in the blood by 15 mg/dL.

Finally, assume both of the above imaginary hormones are released at the same time and the concentration of glucose in the blood increases by 50 mg/dL.

This is an example of ___________.

synergism

Match the following characteristics to the class of hormone associated with that characteristic.
Hydrophobic

steroid hormones

Match the following characteristics to the class of hormone associated with that characteristic.
Produces a long lasting effect on target cells

steroid hormones

Match the following characteristics to the class of hormone associated with that characteristic.
can be produced before it is needed and stored in vesicles

peptide hormones

Match the following characteristics to the class of hormone associated with that characteristic.
circulates through the blood with a relatively short half life

peptide hormones

Match the following characteristics to the class of hormone associated with that characteristic.
binds to receptors in the plasma membrane of target cells

peptide hormones

What is the traditional definition of a hormone?

Chemical messengers that are transported through the blood to a distant target via bulk flow and
act at low concentration

What processes do hormones control?

metabolism
internal environment (aka homeostasis)
reproduction

How do hormones effect target cells?

hormones control the rate of enzymatic reactions
transport of ions or molecules across cell membranes
gene expression and protein synthesis

How is hormone activity terminated, and why is this important?

Hormones in blood: enzymes in liver and kidneys
Hormones bound to a receptor:
degraded by membrane enzymes
degraded by receptor mediated endocytosis
This is important because the high hormone concentration can cause issues in the body.

Which generally has a slower and longer term influence over bodily functions- the nervous system or the endocrine system?

hormones (endocrine system)

What are the 3 main categories of hormones

steroid, peptide, and amino acid derived hormones (e.g. catecholamines)

Peptide hormone properties

hydrophilic
transported through the blood with some half life.
often start as a pre pro hormone

pre-pro-hormone

A pre-pro-hormone is an inactive peptide precursor of an inactive pro-hormone.

Steroid hormone properties

derived from cholesterol
hydrophobic
produced in only a few organs; adrenal gland and gonads

Amine hormone properties

Function as GPCR and are derived from tryptophan and tyrosine
Examples include- epinephrine, norepinephrine, melatonin, and thyroxine produced by the thyroid gland.

What types of responses does peptides hormones have on the target?

modification of existing proteins and induction of new protein synthesis

What types of responses do steroid hormones have on the target?

Induction of new protein synthesis

What types of responses do amine hormones have on the target?

Catecholamines- modification of existing proteins. Thyroid hormones- induction of new protein synthesis

What type of receptor does peptide hormones typically activate?

membrane receptor proteins on the target cell to trigger a signal transduction pathway.

What type of receptor does steroid hormones activate?

to protein receptors in the cytoplasm or nucleus on the target cell.

What type of receptor does amine hormones activate?

cell surface receptors

function of the pituitary gland

the hypothalamus tells the pituitary gland to produce and release hormones that affect other areas of your body. AKA master gland

Describe the structure of the pituitary gland.

The anterior pituitary (adenohypophysis) is large and is derived from epithelial tissue while the posterior pituitary (neurohypophysis) is smaller and is derived from nervous tissue.

What hormones does the anterior pituitary release?

Prolactin,thyroid stimulating hormone, adrenocorticotropic hormone, follicale stimulating hormone, luteinizing hormone, and growth hormone.

prolactin function

milk production

Growth hormone function

directly increases cell division during development, growth, and tissue repair.
stimulates liver to release insulin- like growth factors.
IGF- have a similar effect as growth hormone.

Thyroid stimulating hormone function

stimulates thyroid gland; causes the thyroid gland to release more thyroid hormone.
The thyroid hormone increases basal metabolic rate and heat production.

ACTH function

Tropic hormone that regulates cortisol and androgen production

FSH function

stimulates gamete production in gonads.
females- follicle maturation
male- sperm production

luteinizing hormone function

stimulates hormone production in gonads
Ovary: ovulation-----> androgens ( produced highly to replace estrogen when women reach menopause)
Men: testosterone production

How does the hypothalamus regulate the anterior pituitary?

The hypothalamus releases hormones into the blood and travels through the hypothalamic- hypophyseal portal vessel to carry hormones to the anterior pituitary.

What is the function of calcium in the body?

involved in muscle contraction, conduction nerve impulses, blood clotting, and component of bones & teeth

What causes Goiter?

iodine deficiency

What hormones does the hypothalamus release?

TRH- thyrotropin releasing hormone
GnRH-growth hormone releasing hormone
CRH- corticotropin releasing hormone
Somatostatin and dopamine
All released from the hypothalamus into the blood and travels to the anterior pituitary.

What hormones does the posterior pituitary release?

vasopressin and oxytocin

vasopressin function

stimulates water reabsorption in kidneys

oxytocin function

uterine contractions and milk ejection

How does the hypothalamus regulate the posterior pituitary?

the hypothalamus creates the oxytocin and vasopressin and sends signals to store and release the hormones.

tropic hormone

hormone that stimulates the secretion of another hormone

What is an example of a tropic hormone?

thyroid stimulating hormone (TSH)

Synergism

when the combined effects of two hormones is greater than the sum of each effect on its own.

Permissiveness

when the second hormone is required for the full effect of the first hormone.

Antagonism

when one hormone opposes the action of another (glucagon opposes insulin)

Describe the properties of epinephrine as a hormone.

the net effect is that it causes fast increase in blood sugar and fatty acids for "fight or flight" response (short term stress).

How is the release of cortisol regulated by the hypothalamus and the pituitary?

The release of cortisol is controlled by the hypothalamic pituitary adrenal pathway

What are the effects of the release of cortisol on the concentration of glucose in the blood?

cortisol protects against hypoglycemia via permissive effect with glucagon.
- metabolic effects
1. liver- gluconeogenesis and glycogen breakdown (makes new glucose molecules and glycogen is stored in the hepatocytes of the liver.
2. skeletal muscle- breakdown of muscle proteins
3. adipose tissue- enhances lipolysis- breakdown of lipids.
4. immune system- suppresses immune system.
5. causes negative calcium balance
6. influences brain function

What is one danger of using cortisol as an immunosuppressant and how does negative feedback cause this danger?

exogenous administration may shut down cortisol production and adrenal cells because this administration has a negative feedback effect on the anterior pituitary and without cortisol stimulation, the adrenal cells that produce cortisol atrophy. For this reason it is essential for patients taking steroids taper their dose gradually, giving the pituitary and the adrenal glands a chance to recover rather than stopping the drug abruptly.

How is the release of thyroid hormone regulated by the hypothalamus and the pituitary?

Thyrotropin the thyroid releasing hormone is produced in the hypothalamus and released into the capillaries of the hypothalamic hypophyseal portal vessel which travels to the anterior pituitary to stimulate the release of the thyroid hormone.

What are the effects of the release of the thyroid hormone on metabolism?

activate oxidative metabolism/ increase BMR and generates heat./ may alter ion transport across membranes
thyroid hormones are not essential for life in adults but is essential for normal growth and development in children and infants.

How is the release of growth hormone regulated by the hypothalamus and the pituitary?

Growth hormone releasing hormone stimulates growth hormone secretion and growth hormone stimulates IGF's in liver which is another group of hormones that regulate growth.

What are the effects of the release of growth hormone on the growth of bone and soft tissue? Is growth hormone catabolic or anabolic?

Anabolic. Stimulates release of IGF's from liver which stimulates growth of bone and soft tissue Ana's also stimulates cartilage growth.

What 3 hormones regulate calcium homeostasis?

calcitriol, calcitonin, and parathyroid hormone

Where is calcitriol synthesized?

liver and the skin.

Where is calcitonin synthesized?

Parafollicular C cells of thyroid gland

Where is parathyroid hormone synthesized?

chief cells of parathyroid gland

calcitriol function

increases absorption of calcium and phosphate

calcitonin function

Lowers blood calcium levels

parathyroid hormone function

increases blood calcium