Endocrine System Flashcards

1
Q

Nervous System

A

Neurotransmitters released by neurons relay signals from one part of the body to another part of the body.

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1
Q

how is the endocrine system similar to the nervous system?

A

Like the nervous system, the endocrine system acts to coordinate the functions of various body systems.

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2
Q

Endocrine System

A

Chemical mediators called hormones are released from one part of the body and travel (usually via the blood) to another part of the body.

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3
Q

What are the chemical mediators released by the nervous system?

A

Neurotransmitters.

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4
Q

How do neurotransmitters relay signals in the nervous system?

A

They are released by neurons and relay signals from one part of the body to another.

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5
Q

What are the chemical mediators released by the endocrine system?

A

Hormones.

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6
Q

How do hormones travel in the body in the endocrine system?

A

They travel through the bloodstream to target cells.

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7
Q

How do the endocrine and nervous systems work together to coordinate body functions?

A

They work together using chemical mediators to coordinate the functions of organs and systems in the body.

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8
Q

What form do mediators take in the nervous system?

A

Neurotransmitters.

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9
Q

What form do mediators take in the endocrine system?

A

Hormones

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10
Q

How do neurotransmitters released by a neuron differ from hormones released by a gland cell in terms of target cells?

A

Neurotransmitters released by a neuron target specific types of cells located close to the neuron, whereas hormones released by a gland cell typically target many different types of cells located in different regions of the body.

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11
Q

What is the difference in the duration of effects between neurotransmitters and hormones?

A

Neurotransmitters have relatively quick effects and a short duration because they only need to travel across the synapse to their target cell and are quickly inactivated. Hormones, on the other hand, have much slower effects and a longer duration because they must travel through the bloodstream to reach their target cells and remain active for a period.

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12
Q

What are cells or groups of cells in the body that release substances called?

A

Glands

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13
Q

What distinguishes endocrine glands from exocrine glands in terms of secretion?

A

Endocrine glands secrete hormones into the blood, while exocrine glands secrete substances into ducts that transport them to the external environment.

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14
Q

What is the primary mode of secretion for endocrine glands?

A

Endocrine glands primarily secrete hormones into the bloodstream.

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15
Q

Give an example of a substance secreted by exocrine glands.

A

Examples include sweat, saliva, and digestive enzymes.

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16
Q

Why are glands that release substances into the gastrointestinal tract classified as exocrine glands?

A

Because the space within the gastrointestinal tract is continuous with the external environment.

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17
Q

What determines whether an organ contains only endocrine glands, only exocrine glands, or both?

A

It depends on the specific function of the organ. Some organs contain only endocrine glands, some contain only exocrine glands, while others contain both types.

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18
Q

What is the significance of the digestive tract being considered part of the “external environment”?

A

It explains why glands that release substances into the gastrointestinal tract are classified as exocrine glands, as the tract is continuous with the external environment.

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19
Q

How do hormones reach their target cells?

A

Hormones travel through the bloodstream until they reach their target cell, which has a receptor specific to that hormone.

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20
Q

What are artificial hormone analogues, and how do they interact with receptors?

A

Artificial hormone analogues are molecules designed to mimic natural hormones. They can bind to hormone receptors, either mimicking the hormone’s effects (agonist) or blocking the hormone from binding (antagonist).

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21
Q

What is the function of tamoxifen, and how does it interact with estrogen receptors?

A

Tamoxifen is an artificial analogue of estrogen. It acts as an antagonist when it binds to estrogen receptors in breast tissue, fighting breast cancer. However, it acts as an agonist when it binds to estrogen receptors in uterine tissue, potentially increasing the risk of uterine cancer.

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22
Q

Why is it important to consider the relative benefits and risks of using tamoxifen?

A

It is important because tamoxifen’s effects can vary depending on the tissue it interacts with. While it can be beneficial in treating breast cancer, it may also carry risks, such as increasing the risk of uterine cancer.

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23
Q

How do water-soluble hormones differ from lipid-soluble hormones in terms of administration?

A

Water-soluble hormones must be injected directly into the bloodstream, whereas lipid-soluble hormones can be taken orally.

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24
Q

What is the mode of transport for water-soluble hormones in the blood?

A

Water-soluble hormones can travel through the blood in a free form.

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25
Q

Where are the receptors for water-soluble hormones located on the target cell?

A

The receptors for water-soluble hormones are located on the target cell’s cell membrane.

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26
Q

How do lipid-soluble hormones differ from water-soluble hormones in terms of administration?

A

Lipid-soluble hormones can be taken orally, while water-soluble hormones must be injected.

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27
Q

What is the mode of transport for lipid-soluble hormones in the blood?

A

Lipid-soluble hormones require a transport protein to carry them through the blood.

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28
Q

Where are the receptors for lipid-soluble hormones located on the target cell?

A

The receptors for lipid-soluble hormones are located inside the target cell.

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29
Q

What are some stimuli that can induce a gland to secrete a hormone?

A

Stimuli include signals from the nervous system, levels of circulating ions or compounds in the blood, and the action of other hormones.

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30
Q

How are hormone secretions regulated?

A

Hormone secretions are tightly regulated and often involve negative feedback loops, where increasing levels of a hormone in the blood inhibit further release of that hormone.

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31
Q

What role does negative feedback play in hormone regulation?

A

Negative feedback loops are involved in hormone regulation by inhibiting further release of a hormone when its levels in the blood increase, helping maintain homeostasis.

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32
Q

What are some examples of stimuli that can cause an endocrine gland to release a hormone?

A

Examples include input from neurons, the relative levels of circulating ions, and the action of other hormones.

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33
Q

What are some important functions of hormones?

A

Hormones regulate the growth and development of tissues and organs, metabolic processes, the chemical composition of the blood and internal environment, and can cause contraction of cardiac muscle and smooth muscle.

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34
Q

What happens to hormones that are not utilized by the body?

A

Hormones that are not utilized will eventually be deactivated by the liver and excreted by the kidneys.

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35
Q

endocrine glands:

A

parathyroid (4)
pineal
pituitary
thyroid
adrenal

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36
Q

In addition to secreting hormones, these structures have other functions
(Therefore, they are not exclusively “endocrine glands”):

A

hypothalamus
pancreas
ovaries
testes

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37
Q

What structures have functions beyond secreting hormones, thus not exclusively being “endocrine glands”?

A

Exocrine glands

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38
Q

Where is the hypothalamus located in the brain and how is it connected to the pituitary gland?

A

The hypothalamus is a collection of nuclei located in the diencephalon of the brain. It is connected to the pituitary gland via a stalk called the infundibulum.

39
Q

where does the pituitary gland sit

A

within the sella turcica of the sphenoid bone

40
Q

How is the pituitary gland divided, and what hormones are released by each division?

A

The pituitary gland is divided into an anterior lobe and a posterior lobe. The anterior lobe releases seven hormones regulated by hormones from the hypothalamus. The posterior lobe releases two hormones and is an extension of the hypothalamus.

41
Q

How do hormones released by the hypothalamus and pituitary gland enter the bloodstream, and what vascular network facilitates this process?

A

Hormones released by the hypothalamus and both lobes of the pituitary gland enter the bloodstream via capillary networks formed from branches of the internal carotid arteries.

42
Q

what do branches of the internal carotid arteries form?

A

capillary networks
around the anterior and posterior lobes of the pituitary.

43
Q

Where do hormones that enter the pituitary gland enter? Where do they travel to?

A

Hormones released by the pituitary gland enter the bloodstream
via these capillary networks and travel to their target cells in the body.

44
Q

Describe the mechanism of hormone release in the anterior lobe of the pituitary gland.

A

Stimuli trigger the release of regulatory hormones from the hypothalamus, which travel to the pituitary gland via the capillary network. These regulatory hormones either stimulate or inhibit the release of anterior pituitary hormones into the bloodstream.

45
Q

Describe the pathway of hormone release in the anterior pituitary gland.

A

Hypothalamic neurons secrete releasing or inhibiting hormones.

These hormones enter the capillary network and travel down to the anterior pituitary.

The hormones stimulate or inhibit the release of pituitary hormones.

Pituitary hormones enter the bloodstream.

46
Q

Human Growth Hormone (HGH)

A

Stimulates growth and regulates metabolism in various tissues throughout the body.

47
Q

Thyroid Stimulating Hormone

A

Stimulates the thyroid gland to release one of its hormones.

48
Q

Follicle Stimulating Hormone (FSH)

A

Regulates the function of the ovaries in females and testes in males.

49
Q

Luteinizing Hormone (LH)

A

Regulates the function of the ovaries in females and testes in males.

50
Q

Prolactin

A

Stimulates the production of milk from the mammary glands during pregnancy in females. Its function in males is not well understood.

51
Q

Adrenocorticotropic Hormone (ACTH)

A

Stimulates the adrenal cortex to release some of its hormones.

52
Q

Melanocyte Stimulating Hormone (MSH)

A

The function is not well understood, but it is thought to relate to the production of melanin in the skin.

53
Q

How can pituitary gland tumors disrupt the normal regulation of hormone release, using human growth hormone as an example?

A

Tumors of the pituitary gland can disrupt standard harmful feedback mechanisms, leading to excessive hormone secretion. For instance, a cancer of the cells producing human growth hormone can result in abnormally high and continual hormone output, causing excessive enlargement of tissues throughout the body.

54
Q

What is the posterior lobe of the pituitary gland made up of?

A

Axons of certain hypothalamic neurons.

55
Q

How are hormones released by the posterior lobe of the pituitary gland produced?

A

They are produced by hypothalamic neurons and stored in their axon terminals.

56
Q

What triggers the release of hormones from the posterior pituitary gland into the bloodstream?

A

Certain stimuli that trigger action potentials in hypothalamic neurons, leading to the stimulation of hormone release.

57
Q

Where do hypothalamic neurons secrete “pituitary” hormones?

A

Hypothalamic neurons secrete “pituitary” hormones into the posterior pituitary.

58
Q

How do hormones travel from hypothalamic neurons to the posterior pituitary?

A

Hormones travel down the axons of hypothalamic neurons and are stored in the axon terminals of the posterior pituitary.

59
Q

What triggers the release of hormones from the posterior pituitary into the bloodstream?

A

Action potentials reaching the axon terminals of hypothalamic neurons stimulate the release of hormones into the bloodstream.

60
Q

What is the function of oxytocin in females?

A

Oxytocin stimulates uterine contractions during the second labor stage and the milk release from mammary glands after delivery.

61
Q

What is the function of oxytocin in males?

A

The function of oxytocin in males is not well understood.

62
Q

What is the function of antidiuretic hormone (ADH)?

A

ADH inhibits urine production in the kidneys and causes vasoconstriction, leading to increased blood pressure.

63
Q

How does alcohol consumption affect the release of ADH?

A

Alcohol inhibits the release of ADH from the posterior pituitary gland, leading to increased urine production, frequent urination, and dehydration.

64
Q

Where is the pineal gland located?

A

The pineal gland is located in the roof of the diencephalon.

65
Q

What hormone does the pineal gland secrete?

A

The pineal gland secretes melatonin.

66
Q

What effect does melatonin have on the body?

A

Melatonin induces drowsiness.

67
Q

How is the release of melatonin regulated?

A

The release of melatonin is regulated by the amount of ambient light, with increased light levels inhibiting its release and decreased light levels stimulating its release.

68
Q

What stimulates the pineal gland to secrete melatonin?

A

Stimulation by the hypothalamus causes the pineal gland to secrete melatonin.

69
Q

Where is the thyroid gland located?

A

The thyroid gland is in the anterior neck around the thyroid cartilage and trachea.

70
Q

Where are the adrenal glands located?

A

The adrenal glands are located above the kidneys within the abdominal cavity.

71
Q

What are the two main parts of the adrenal glands?

A

Each adrenal gland contains an outer cortex and an inner medulla.

72
Q

What types of hormones does the adrenal cortex secrete?

A

The adrenal cortex secretes three types of steroid hormones: mineralocorticoids, glucocorticoids, and androgens.

73
Q

What are the functions of the three types of steroid hormones secreted by the adrenal cortex?

A

Mineralocorticoids regulate mineral homeostasis.

Glucocorticoids regulate glucose homeostasis.

Androgens are male sex hormones.

74
Q

What are the types of catecholamines that the adrenal medulla secretes?

A

Epinephrine
Norepinephrine

75
Q

What is the function of mineralocorticoids?

A

Mineralocorticoids affect ion levels in the blood, regulating blood pressure and acidity.

76
Q

What is the function of glucocorticoids?

A

Glucocorticoids affect glucose, amino acid, and fatty acid levels in the blood, and inhibit certain inflammatory and immune responses.

77
Q

What are the uses and considerations for glucocorticoids?

A

Glucocorticoids are sometimes prescribed topically or by injection to reduce inflammation associated with conditions like bursitis and tendonitis. However, their use must consider the balance between benefits and risks, as they can induce tissue breakdown.

78
Q

What is the role of androgens?

A

Androgens are male sex hormones that affect libido and serve as an essential source of estrogen for females after menopause.

79
Q

Mineralocorticoids example

A

aldosterone

80
Q

mineralocorticoids

A

Increase blood pressure
(by increasing Na+ and H2O reabsorption in the kidneys)
Decrease the acidity of the blood
(by increasing H+ excretion in the kidneys)

81
Q

example of glucocorticoids

A

cortisol

82
Q

Glucocorticoids

A

Increase the levels of glucose, AAs, and FAs in the blood
(by inducing tissue breakdown)
Inhibit inflammatory and immune responses
(by inhibiting white blood cells)

83
Q

Androgens

A

Promotes libido
Converted into estrogen
(important after menopause

84
Q

What is the adrenal medulla?

A

The adrenal medulla is a modified sympathetic prevertebral ganglia.

85
Q

How do neurons in the adrenal medulla secrete their chemical mediators?

A

Neurons in the adrenal medulla secrete their chemical mediators directly into the blood.

86
Q

What is the dual function of epinephrine and norepinephrine?

A

Epinephrine and norepinephrine function as neurotransmitters when released by sympathetic postganglionic neurons and as hormones when released into the blood by the adrenal medulla cells.

87
Q

What effects do epinephrine and norepinephrine have on the body?

A

These hormones cause widespread sympathetic effects in various tissues around the body.

88
Q

What hormones are secreted by the ovaries?

A

The ovaries secrete estrogen, progesterone, and relaxin.

89
Q

What are the effects of estrogen and progesterone?

A

Estrogen and progesterone collectively regulate many female reproductive functions.

90
Q

What is the function of relaxin?

A

Relaxin affects the pelvic girdle during pregnancy to accommodate the growing fetus and the cervix and uterus during the first stage of labor.

91
Q

What hormone is secreted by the testes?

A

The testes secrete testosterone.

92
Q

What are the effects of testosterone?

A

Testosterone regulates many male reproductive functions.

93
Q

What happens to estrogen and progesterone secretion in women after menopause?

A

Estrogen and progesterone secretion drops significantly after menopause.

94
Q

What are some adverse effects of reduced estrogen and progesterone levels after menopause?

A

Hot flashes, vaginal dryness, mood changes, and osteoporosis.

95
Q

How is Hormone Replacement Therapy (HRT) used to counteract the effects of reduced hormone levels?

A

HRT involves using medications containing estrogen +/- progesterone to boost hormone levels.

96
Q

What are some risks associated with Hormone Replacement Therapy (HRT)?

A

Risks include heart disease, stroke, blood clots, breast cancer, and endometrial cancer, as suggested by studies.