10 - Endocrine System Flashcards Preview

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Flashcards in 10 - Endocrine System Deck (125):

The study of the endocrine system includes several (4) categories:

1. Autocrine chemical messengers.
2. Paracrine chemical messengers.
3. Neurotransmitters
4. Endocrine chemical messengers.


What are autocrine chemical messengers?

An autocrine chemical messenger stimulates the cell that originally secreted it.


Give an example of autocrine chemical messengers.

The chemical messengers secreted by white blood cells during an infection. They can stimulate their own replication rate.


What are paracrine chemical messengers?

Paracrine chemical messengers act locally on nearby cells. These chemical messengers are secreted by one cell type into the extracellular fluid and affect surrounding cells of a different type.


Give an example of a paracrine chemical messenger.

An example is histamine, which is released by certain white blood cells during allergic reactions. Histamine stimulates vasodilation in nearby blood vessels.


What are neurotransmitters?

Neurotransmitters are chemical messenger secreted by neurons that activate an adjacent cell, whether it is another neuron, a muscle cell, or a glandular cell.


What are endocrine chemical messengers?

Endocrine chemical messengers are secreted into the bloodstream by certain glands and cells, which together constitute the endocrine system. These chemical messengers affect cells that are distant from their source.


Give the 10 main regulatory functions of the endocrine system:

1. metabolism
2. control of food intake and digestion
3. tissue development
4. ion regulation
5. water balance
6. heart rate and blood pressure regulation
7. control of blood glucose and other nutrients
8. control of reproductive functions
9. uterine contractions and milk release
10. immune system regulation
(1-5: 1 / 6-9: 2)


Are sweat glands endocrine glands?

No, they are exocrine glands.


Hormones fit into one of two chemical categories. Which?

1. Lipid-soluble hormones
2. Water-soluble hormones.


How are lipid-soluble hormones transported?

In the bloodstream, but because of their low solubility in the aqueous blood, they attach to binding proteins.


How are water-soluble hormones transported?

They can dissolve in blood, so most of them circulate the bloodstream freely.


How are lipid-soluble hormones delivered to tissue?

They need to detach from their binding proteins. Once detached they are small and hydrophobic, which enables them to diffuse across the cell membrane (for instance that of the capillaries).


How are water-soluble hormones delivered to tissue?

They are large and hydrophilic, so they do not diffuse across the cell membrane easily.


Why can some hormones be taken orally, like synthetic estrogen, but others have to be injected, like insulin?

Hormones that are soluble in lipids, such as estrogen, may be taken orally because they can diffuse across the wall of the stomach. Insulin however is a protein hormone and will not be able to diffuse across the wall of the stomach, and will therefore be metabolized and therefore lose its physiological function.


Three types of stimuli regulate hormone release. Which?

humoral, neural and hormonal.


What is meant by humoral stimuli of hormone release?

Blood-borne chemicals (that are not hormones) can directly stimulate the release of some hormones. These chemicals are referred to as humoral stimuli.


Give an example of a humoral stimuli and its hormone.

Glucose levels in the blood directly stimulate insulin secretion by the pancreas.


What is meant by neural stimuli of hormone release?

Some neurons signal hormonal glands directly.


Give an example of a neural stimuli and its hormone.

In response to stress or exercise, the sympathetic division of the autonomic nervous system stimulates the adrenal gland to secrete epinephirne and norepinephrine.


What is meant by hormonal stimuli of hormone release?

When a hormone stimulates the secretion of other hormones.


Give an example of hormonal stimuli of hormone release.

Hormones from the hypothalamus and anterior pituitary gland regulate the secretion of thyroid hormones from the thyroid gland.


Two major mechanisms maintain hormone levels n the blood within a homeostatic range. Which?

1. Negative feedback
2. Positive feedback.


What is meant by hormone regulation by negative feedback?

Negative feedback is where the hormone's secretion is inhibited by the hormone itself once blood levels have reached a certain point. The hormone may inhibit the action of other, stimulatory hormones to prevent the secretion of the hormone in question.


What is meant by hormone regulation by positive feedback?

Some hormones, when stimulated by a tropic hormone, promote the synthesis and secretion of the tropic hormone in addition to stimulating their cell. In turn, this stimulates further secretion of the original hormone.


Lipid-soluble hormones bind to which type of receptors?

Nuclear receptors.


Water-soluble hormones bind to which type of receptors?

Membrane-bound receptors.


What is a nuclear receptor?

A receptor type that most often is located in the target cell nucleus or cytoplasm. Often this leads to a change in the expression of DNA in that particular cell.


What is a membrane-bound receptor?

A receptor type that extend across the target cell membrane.


What is the hormone response element?

The sequence of DNA that is the target of the receptor's actions.


What is the transcription factor?

The combination of the hormone and its receptor. They are named such because they, together, regulate the transcription of the hormone response element of the DNA.


What is the effect of the steroid hormone aldosterone on the kidneys?

Aldosterone affects its target cells in the kidneys by stimulating the synthesis of proteins that increase the rate of Na+ and K+ transport. The result is a reduction in the amount of Na+ and an increase in the amount of K+ lost in urine.


Membrane-bound receptors activate responses in two ways. Which?

1. Some receptors alter the activity of G proteins at the inner surface of the plasma membrane.
2. Other receptors directly alter the activity of intracellular enzymes.


G proteins consists of subunits. Which?

3 subunits. From largest to smallest, they are called: alpha, beta and gamma.


How would a G protein look during its inactive state?

In the inactive state, a guanine diphosphate (GDP) is bound to the alpha subunit of each G protein.


How would a G protein look during its active state?

In the active state, guanine triphosphate (GTP) is bound to the alpha subunit.


Before the hormone binds to its receptor, where is the G-protein?

Before the hormone binds to its receptor, the G protein consists of three subunits, with GDP attached to the alpha subunit, and freely floats in the plasma membrane.


What happens to the receptor just after the hormone has bound to it?

After the hormone binds to its membrane-bound receptor, the receptor changes shape, and the G protein binds to it. GTP replaces GDP on the alpha subunit of the G protein.


After the hormone binds to its membrane-bound receptor, the receptor changes shape, and the G protein binds to it. GTP replaces GDP on the alpha subunit of the G protein. What happens after, but still while the hormone is attached?

The G protein separates from the receptor. The GTP-linked alpha subunit activates cellular responses, which vary among target cells.


What happens to the receptor when the hormone is no longer attached?

When the hormone separates from the receptor, additional G proteins are no longer activated.


How does inactivation of the alpha subunit of a G protein occur?

Inactivation of the alpha subunit occurs when phosphate is removed from the GTP, leaving GDP bound to the subunit.


Why are hormones that target membrane-bound receptors a part of a fast response?

They typically produce an instantaneous response because the second messenger they activate influences already existing enzymes.


What is meant by signal amplification in regards to hormones?

Each receptor typically produce thousands of second messengers, which leads to a cascade effect and ultimately amplification of the hormonal signal.


Short: what is the pituitary gland?

The pituitary gland (hypophysis) is a small gland about the size of a pea. It rests in a depression of the sphenoid bone inferior to the hypothalamus of the brain.


Short: what is the hypothalamus?

The hypothalamus is an important autonomic nervous system and endocrine control center of the brain. It is located inferior to the thalamus.


The pituitary gland has two parts.

The anterior pituitary and posterior pituitary.


What is the tissue of the anterior pituitary gland, and what is its embryonic origin?

It is made up of epithelial cells derived from the embryonic oral cavity.


What is the tissue of the posterior pituitary gland?

It is an extension of the brain and is composed of nerve cells.


What is the hypothalamic-pituitary portal system?

The capillary beds and veins that transport the releasing and inhibiting hormones between the hypothalamus and the pituitary gland.


What is the infundibulum?

Infundibulum and infundibular stalk are alternative names for the pituitary stalk, the connection between the hypothalamus and the posterior pituitary. (Wikipedia)


How does the hypothalamus directly innervate the pituitary?

Stimulation of neurons within the hypothalamus controls the secretion of hormones from the posterior pituitary. The cell bodies of these neurons are in the hypothalamus, and their axons extend through the infundibulum to the posterior pituitary.


What are the hormones secreted from the anterior pituitary gland?

1. Growth hormone
2. Thyroid-stimulating hormone (TSH)
3. Adrenocorticotropic hormone (ACTH)
4. Melanocyte-stimulating hormone (MSH)
5. Lutenizing hormone (LH)
6. Follicle-stimulating hormone (FSH)
7. Prolactin


What is the target tissue of Growth hormone?

Most tissues


What is the target tissue of Thyroid-stimulating hormone (TSH)?

Thyroid gland


What is the target tissue of Adrenocorticotropic hormone (ACTH)?

Adrenal cortex


What is the target tissue of Melanocyte-stimulating hormone (MSH)?

Melanocytes in skin


What is the target tissue of Lutenizing hormone (LH)?

Ovary in females, testis in males


What is the target tissue of Follicle-stimulating hormone (FSH)?

Follicles in ovary in females. Seminiferous tubules in males.


What is the target tissue of Prolactin?

Ovary and mammary gland in females, testis in males.


What is the function of Growth hormone?

Increases gene expression, breakdown of lipids and release of fatty acids from cells; increases blood glucose levels.


What is the function of Thyroid-stimulating hormone (TSH)?

Increases thyroid hormone secretion (thyroxine and triiodothyronine)


What is the function of Adrenocorticotropic hormone (ACTH)?

Increases secretion of glucocorticoid hormones, such as cortisol; increases skin pigmentation at high concentrations.


What is the function of Melanocyte-stimulating hormone (MSH)?

Increases melanin production in melanocytes to make skin darker in color.


What is the function of Lutenizing hormone (LH)?

Promotes ovulation and progesterone production in ovary; promotes testosterone synthesis and support for sperm cell production in testis.


What is the function of Follicle-stimulating hormone (FSH)?

Promotes follicle maturation and estrogen secretion in ovary; promotes sperm cell production in testis.


What is the function of Prolactin?

Stimulates milk production and prolongs progesterone secretion following ovulation and during pregnancy in women; increases sensitivity to LH in males.


What are the hormones secreted by the posterior pituitary gland?

1. Antidiuretic hormone (ADH)
2. Oxytocin


What are the hormones secreted by the thyroid gland?

1. Thyroid hormones (thyroxine, triiodothyronine)
2. Calcitonin


What are the hormones secreted by the parathyroid gland?

1. Parathyroid hormone


What are the hormones secreted by the adrenal medulla?

1. Epinephrine mostly, and some norepinephrine.


What are the hormones secreted by the adrenal cortex?

1. Mineralcorticoids (aldosterone)
2. Glucocorticoids (cortisol)
3. Adrenal androgens


What are the hormones secreted by the pancreas?

1. Insulin
2. Glucagon


What are the hormones secreted by the testes?

1. Testosterone


What are the hormones secreted by the ovaries?

1. Estrogens, progesterone


What are the hormones secreted by the uterus, ovaries, inflamed tissues?

1. Prostaglandins


What are the hormones secreted by the thymus?

1. Thymosin


What are the hormones secreted by the pineal gland?

1. Melatonin


I can finish the table at page 276 if I feel like I have the time/need to. Will focus on what the book focuses on.



What happens if a person has a deficiency of growth hormone as a child?

They risk not growing normally. Will be proportioned, but too small for their age. Called a pituitary dwarfism.


How can we treat pituitary dwarfism?

Can be treated by administering growth hormone. Is achieved through growth of GH in bacteria.


What can be a cause of excess growth hormone?

Tumors in the pituitary gland.


What happens if excess growth hormone is present before bones finish growing in length?

The person's bones will grow abnormally long, and the person becomes very tall. This condition is called giantism.


What happens if excess growth hormone is present after growth in bone length is complete?

Then growth continues only in bone diameter, and the result is that the facial features and hands become abnormally large. The condition is called acromegaly.


Where are the thyroid hormones synthesized and stored?

In the thyroid follicles, which are small spheres with walls composed of simple cuboidal epithelium.


What could happen to someone if their iodine intake is too low?

It can cause a condition known as goiter. Iodine is needed for the synthesis of thyroid hormones. When levels of thyroid hormones in the blood stream are too low, the hypothalamus and pituitary will increase their production of TSH (thyroid-stimulating hormone), which is a hormone that increases production of thyroid hormones. Such an increase will cause an enlargement of the thyroid gland, which is the main symptom of goiter.


Untreated hypothyroidism can cause cretinism in infants. What are the symptoms of cretinism?

Mental retardation, short stature, and abnormally formed skeletal structures.


What are the symptoms of untreated hypothyroidism in adults?

Decreased metabolic rate, sluggishness, a reduced ability to do routine tasks, and myxoedema which is the accumulation of fluid and other molecules in the subcutaneous tissue.


An elevated rate of thyroid hormone secretion can cause what kinds of problems?

Hyperthyroidism causes an increased metabolism, extreme nervousness, and chronic fatigue.


What is Graves disease?

Graves disease is a type of hyperthyroidism that results when the immune system produces abnormal proteins that are similar in structure and function to TSH.


What are the parathyroid glands?

The four parathyroid glands are embedded in the posterior wall of the thyroid gland. The parathyroid glands secrete a hormone called parathyroid hormone (PTH).


What is the function of parathyroid hormone?

It regulates the blood calcium levels.


What hormones are released from the adrenal medulla?

Epinephrine and norepinephrine.


What causes release of epinephrine and norepinephrine from the adrenal medulla?

The sympathetic nervous system.


What are the five major effects of hormones released from the adrenal medulla (epinephrine and norepinephrine.)?

1. Increased breakdown of glycogen and adipose tissue (fat).
2. Increased heart rate.
3. Vasoconstriction of smooth muscle arteries to internal organs.
4. Increased blood pressure due to heart rate and vasoconstriction.
5. Increased metabolic rate of several tissues, especially skeletal muscle, cardiac muscle and nervous tissue.


What is the function of mineralcorticoids released by the adrenal cortex?

They help regulate blood volume and blood levels of K and Na.


What is the function of aldosterone released by the adrenal cortex?

Aldosterone causes Na and water to be retained in the body and increases the rate at which K is eliminated.


What is the stimuli that causes aldosterone to be released from the adrenal cortex?

Increased blood K+ levels or decreased blood Na+ levels cause the adrenal cortex to increase the secretion of aldosterone into the general circulation.


What happens in the kidneys during low blood pressure?

The kidneys detect a decrease in blood pressure. In response, they increase the secretion of renin into the general circulation.


What are the functions of Renin, a protein molecule that is released from the kindeys during low blood pressure conditions?

Renin converts angiotensinogen to angiotensin I. Angiotensin I is converted by an enzyme into Angiotensin II. Angiotensin II causes constriction of blood vessels, resulting in increased blood pressure.


Angiotensin II has two functions. Which?

1. Causes a constriction of blood vessels, resulting in increased blood pressure.
2. Increases the secretion of aldosterone by the adrenal cortex.


What are the effects of increased secretion of aldosterone?

Aldosterone stimulation of the kidneys causes Na+ retention, K+ secretion, and decreased water loss. This leads to increased blood volume, which help raise blood pressure


What is cortisol?

Cortisol is a glucocortiocid hormone released by the middle layer of the adrenal cortex. Cortisol causes the liver to convert amino acids to glucose, and acts on adipose tissue causing fatty acids to be released into the blood. Cortisol also reduces the inflammatory and immune responses.


Androgens are hormones that are secreted by ..

The adrenal cortex in both sexes, as well as the testes in men.


What are pancreatic islets?

Pancreatic islets, or "islets of Langerhans", is the endocrine part of the pancreas.


The pancreatic islets secrete three hormones. Which?

1. Insulin
2. Glucagon.
3. Somatostatin


What happens normally when blood sugar is low?

When blood glucose decreases, other tissues rapidly break down lipids and proteins to provide an alternative energy source. As lipids are broken down, the liver converts some of the fatty acids to acidic ketones, which are released into the blood. This can reduce the pH of the body fluids below normal, a condition called acidosis.


What happens normally when blood sugar is too high?

If blood glucose levels are too high, the kidneys produce large volumes of urine containing substantial amounts of glucose. Because of the rapid loss of water in the form of urine, dehydration can result. Insulin is secreted.


What is the cause of type 1 diabetes mellitus?

Type 1 diabetes mellitus occurs when too little insulin is secreted from the pancreas.


What is the cause of type 2 diabetes mellitus?

Type 2 diabetes mellitus is caused by insufficient numbers of insulin receptors or by defective receptors that do not respond normally to insulin.


What are the symptoms of type 1 diabetes mellitus?

Excessive urine production, because the body is trying to rid itself of the excess blood sugar. This also causes dehydration and thirstiness. Lack of energy.


What is glucagon?

Glucagon is a hormone that is released from the alpha cells when blood glucose level are low. Glucagon binds to membrane-bound receptors primarily in the liver, causing the glycogen stored in the liver to be converted to glucose. The glucose is the then released into the blood to increase blood glucose levels.


What is somatostatin?

Somatostatin is a hormone that is released by the delta cells in response to food intake. Somatostatin inhibits the secretion of insulin and glucagon and inhibits gastric tract activity.


What is the thymus?

Thymus, brissel, avlangt, grårødt, lappet lymfoepitelialt organ bak brystbenet; hovedorgan i immunsystemet og modningssted for T-celler


What is the function of thymosin, released by the thymus?

It aids the development of white blood cells called T cells.


What is the function of melatonin, released by the pineal gland?

It is thought to decrease the secretion of LH and FSH by decreasing the release of hypothalamic releasing hormones. Secretion of melatonin is dependent on light stimulation.


Norwegian word for goiter.



Beta cells in the pancreas release which hormone?



T/F: Anabole steroider er trygt å bruke, og burde tillates i enkelte idrettsgrener



T/F om anabole steroider: Bivirkninger: Menn kan utvikle gynekomasti (vekst av bryster hos menn), få redusert volum på testiklene og lide hårtap. Kvinner vil gjennomgå en maskulinisering, dypere
stemme, mer kroppshår, større klitoris. Begge kjønn kan utvikle infertilitet.



T/F Anabole steroider kan gi hypertrofi av hjetemuskulaturen, høyere blodtrykk, økt risiko for hjerteinfarkt og hjerneslag



En bivirkning av anabole steroider hos ungdom er stans i skjelettveksten, med kortvoksthet som følge.



T/F: Hyperthyreose er en tilstand med økt effektiv mengde sirkulerende, frie, thyroideahormoner (tyroksin, T4 og/eller trijodtyronin, T3)



T/F: Thyroideahormoner produseres i bukspyttkjertlen



T/F: Tyroksin (T4) er et hormon som i stor grad fungerer som et pro-hormon og omdannes til det 3-4 ganger mer potente trijodtyronin (T3)



T/F: Vanlige symptomer på hypertyreose er hjertebank, rastløshet, vekttap til tross for god matlyst, eksoftalmus, fin tremor, forstørret skjoldbruskkjertel (struma)