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Flashcards in Endocrine system Deck (67):
1

Endocrine glands

synthesize and secrete chemical substances called HORMONEs directly into the circulatory system
-include: pituitary, hypothalamus, thyroid, parathyroids, adrenals, pancreas, testes, ovaries, pineal glands, kidneys, gastrointestinal glands, heart and thymus

2

Exocrine Glands

such as the gallbladder,
-secrete substances transported by ducts

3

Adrenal Glands

located on the top of the Kidneys and consists of the adrenal cortex and the adrenal medulla

4

What stimulates the adrenal cortex and what is the result of the stimulation?

-ACTH (adrenocorticotropic mormon which is produced by the anterior pituitary stimulates the adrenal cortex to produce more than 2 dozen different steroid hormones called ADRENOCORTICAL STEROIDS or CORTICOSTEROIDS

5

Transcortins

the complex that is formed in the blood, when the corticosteroids are bound to transport proteins \

6

What are the three major classes of corticosteroids?

1) Glucocorticoids
2)Mineralocorticoids
3) Corticol Sex Hormones

7

Glucocorticoids

-such as cortisol and cortisone are involved in glucose regulation and protein metabolism

-raise blood glucose levels by promoting protein breakdown and gluconeogenesis and decreasing protein synthesis
-increase plasma glucose levels
-antagonistic to the effects of insulin
-release amino acids from skeletal muscle as well as lips from adipose tissue
-also promote the peripheral use of lipids and have anti-inflammatory effects

8

Mineralcorticoids

-ALDOSTERONE-
-regulate plasma levels of sodium and potassium and consequently the total extracelular fluid volume
-Aldosterone causes active reabsorption of sodium and passive reabsorption of water in the nephron of the kidney. This results in an increase in BLOOD VOLUME AND BP
-stimulated by angiotensen II and inhibited by ANP (Atrial natriuretic peptide)

9

Excess production of Aldosterone causes?

results in excess retention of water with resulting hypertension (High BP)

10

Corticol Sex hormones

-in both men and some the adrenal cortex secretes small amounts of ANDROGENS (male sex hormones) like andiostenedioine and dehydroplandrosterone

-in men, most of the androgens are produced by the testes
-in women, overproduction of the adrenal androgens may have maculating effects, such as excessive facial hair

11

Adrenal Medulla

-produces EPINEPHRINE (adrenaline) and noreepinephrine (noradrenaline)

12

What class does epinephrine and norepinephrine belong to?

CATECHOLAMINES

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Epinephrine

-increases the conversion of glycogen to glucose in the liver and muscle tissue causing an increase in blood glucose levels and an increase in the basal metabolic rate
-inhibits other functions, such as digestion, that are not immediately important for survival

14

Epinephrine and Norepinephrine SImiliarities

both increase the rate and strength of the heartbeat and dilate and constrict blood vessel in such as way to increase the blood supply to the kidneys, skin, and digestive tract
-also promote the release of lipids by adipose tissue
-THese effects are known as the "fight or flight response"
-both are also NEUROTRANSMITTERS

15

Pituitary Gland

hypophysis
-a small, trilled gland at the basis of the brain
-the two main lobes are anterior and posterior
-Pituitary gland hangs below the hypothalamus and is connected to it by a slender cord call infundibulum

16

Anterior Pituitary

-synthesize both direct hormones which directly acts on their target organs
-also synthesize tropic hormones which stimulate other endocrine glands to release hormones

17

what regulates the hormonal secretion of the anterior pituitary?

regulated by the hypothalamic hormones called releasing/inhibiting hormones or factors

18

Direct hormones of the anterior pituitary

-Growth Hormone (GH, somatotropin)
-Prolactin

19

Growth Hormone

-(GH, somatotropin)
-promotes bone and muscle growth
-promotes protein synthesis and lipid mobilization and catabolism

20

In children what can a deficiency in growth hormone result in?

stunted growth (Dwarfism)

21

In children what can an excess of growth hormone result in?

Gigantism

22

In adults what can overproduction of Growth Hormone cause?

Acromegaly, a disorder characterized by disproportionate overgrowth of bone, especialy in the skull, jaw, feet, and hands

23

Prolactin

stimulates milk production in female mammary glands

24

Tropic hormones of the Anterior Pituitary

-adrenocorticotropic Hormone (ACTH)
-Thyroid Stimulating Hormone (TSH)
-Lenteinizing Hormone (LH)
-Follicle-stimulating hormone (FSH)
-Melanocyte-stimulating hormone (MSH)
-Endorphins

25

Adrenocorticotropic Hormone

ACTH
-stimulates the adrenal cortex to synthesize and secrete gulcocorticoids
-regulated by corticotrophin-releasing-factor (CRF)

26

Thyroid Stimulating Hormone

stimulates the thyroid gland to synthesize and release thyroid hormone, including thyroxine

27

Lenteinizing Hormone

LH
-in women, LH stimulates ovulation and maintenance of the CORPUS LUteum
-responsible for regulating progesterone secretion in women
-In men, LH stimulates the interstitial cell soy the testes to synthesize testosterone

28

Follicle-stimulating hormone

FSH
-in women, FSH causes maturation of ovarian follicles, which secretes estrogen
-in men, FSH stimulates maturation of the seminiferous tubules and sperm production

29

Melanocyte-stimulating Hormone

MSH
-secreted by the intermediate lobe of the pituitary
-in mammals the function is unclear but in frogs, MSH causes darkening of the skin via the induced dispersion of molecules of pigment in melanophore cells

30

Posterior Pituitary

Neurohypophysis
-doesn't synthesize hormones
-it stores and releases the peptidehormone, OXYTOCIN and ANTIDURETIC HORMONE

31

Where are oxytocin and ADH produced?

produced on the neurosecretory cell of the hypothalamus

32

Oxytocin

secreted during childbirth
-increases the strength and frequency of uterine muscle contractions
-oxytocin secretion is also induced by suckling
-stimulates milk secretion in mammary glands

33

Antiduretic Hormone

ADH
-increases the permeability of the nephron's COLLECTING DUCTS to water, thereby promoting water reabsorption and increasing blood vole which increases Blood pressure
-is secreted when plasma osmolarity increases, which is sensed by osmoreceptors in hypothalamus or when Blood volume decreases is sense by baroreceptors in circulatory systems

34

Hypothalamus

-part of the forebrain and dis located directly above the pituitary gland
-receives neural transmissions from other parts of the brian and form peripheral nerves that trigger specific responses from its neurosecretory cells

35

Neurosecretory cells

regulate pituitary gland secretions via negative feedback mechanisms and through the actions of inhibiting and releasing hormones

36

Hypothalamus interactions with posterior pituitary

-neurosecretory cells in the hypothalamus synthesize both oxytocin and ADH and transport them via their axons into the posterior pituitary for secretion

37

Thyroid

thyroid hormones affect the function of nearly every organ system in the body

38

Thyroid hormones in children

-thyroid hormones are essential for growth and neurological development

39

Thyroid Hormones in adults

-thyroid hormones increase the rate of metabolism throughout the body and are essential for maintenance of metabolic stability

40

What are the thyroid hormones?

Thyroxine (T4) and Triiodothyronine (T3)

41

How are the thyroid hormones formed?

formed from the glycoprotein (THYROGLOBULIN), which is synthesized in thyroid cells
-because of the specific territory structure of the glycoprotein, iodinated tyrosine residues present in thyroglobulin are able to bind together to form active thyroid hormones

42

What are some of the characteristics of the thyroid hormones?

-T3 is 5 times more potent than T4
-T4 and T3 are transported via plasma proteins. Approximately 99.5% of these hormones are bound to proteins, but only an unbound hormone is able to enter a cell and elicit a cellular response

-All of the T4 in the body is formed and secreted by the thyroid gland, however only 20% of T3 is produced by the thyroid gland
-The majority of T3 is produced by the conversion of T4 to T3 by the enzyme 5-monodeiodase, found primarily in the peripheral tissues

43

Hypthyroidism

-thyroid hormones are under secreted or not secreted at all
-common symptoms: slowed heart rate and respiratory rate, fatigue, cold tolerance, and weight gain

44

in infants what is hypothyroidism called?

Cretinism- characterized by mental retardation and short stature

45

Hypothyroidism treatment

-supplementation of thyroid hormones via synthetic or animal derived products

46

Hyperthyroidism

-the thyroid is overstimulated, resulting in over secretion of thyroid hormones
-symptoms: increased metabolic rate, feelings of excessive warmth, produce sweating, palpitations, weight loss, and protruding eyes

47

Hyperthyroidism treatment

can be treated by antithyroid medications that suppress the thyroids release of excess hormones

OR

ablation of the thyroid with radiation. After ablation, the thyroid no longer produces thyroid hormone, and the patient must take thyroid supplementation for the rest of his/her life

48

Calcitonin

-decreases plasma Ca2+ concentration by inhibiting the release of Ca2+ from bone
-Calcitonin secretion is regulated by plasma Ca2+ levels
-antagonistic to parathyroid hormone

49

Pancreas

-both an exocrine organ and endocrine organ
-exocrine function is performed by the cells that secrete digestive enzymes into the small intestine via a series of ducts

-endocrine function is performed by small glandular structures called ISLETS OF LANGERHAS

50

Islets of langerhas

composed of alpha and beta cells
-alpha cells produce and secrete glucagon
-beta cells produce and secrete insulin

51

Endocrine hormone secreted by the pancreas

Glucagon
Insulin

52

Glucagon

stimulates protein and fat digestion, the conversion of glycogen to glucose, and glucogenesis----all of which serve to INCREASE blood glucose levels
-actions are antagonistic to insulin

53

Insulin

-protein hormone secreted in response to a high blood glucose concentration
-stimulates the uptake of glucose by muscle and adipose cells and the storage of glucose as glycogen in muscle and liver cells---THUS LOWERING BLOOD glucose levels
-also stimulates the synthesis of fats from glucose and uptake of amino acids
-antagonisitic of glucagon and glucocorticoids

54

What does underproduction of insulin/insensitivity of insulin lead to?

Diabetes mellitus- characterized by hyperglycemia (high blood glucose levels)

55

What is the most common endocrine disorder?

diabetes and if not treated can lead to long term complications involving the eyes, nerves, kidneys, and blood vessels

56

Parathyroid Glands

are four small, pea-shaped structures embedded in the posterior surface of the thyroid
-these glands synthesize and secrete parathyroid hormone PTH

57

Parathyroid Hormone

regulates the plasma Ca2+ conc.
-PTH raises the Ca2+ conc. int eh blood by stimulating Ca2+ release from the bone and decreasing Ca2+ excretion in the kidneys

58

Kidneys

-when the blood volume falls the kidneys produce renin
-also produce erythropoietin

59

Renin

an enzyme that converts the plasma protein angiotenstrogen to angiotensin I. Angiotensin is then converted to angiotensin II, which stimulates the adrenal cortex to secrete ALODSTERONE.

-aldosterone helps restore blood volume by increasing sodium reabsorption of the kidneys, leading to an increase in fluid retention. This removes the initial stimulus for renin production

60

erythropoietin

-a glycoprotein that stimulates RBC production. It is normally produced in the kidneys

causes the following:
-stimulation of the stem cells to differentiate into rubriblasts
-increased rate of mitosis
-increased rate of reticulocytes front eh bone marrow
-increased hemoglobin formation, which results int eh critical HgB (hemoglobin) conc. necessary for RBC maturity to be reacted at a more rapid rate

61

Gastrointestinal hormones

-ingested food stimulates the stomach to release the mormon Gastrin

62

Gastrin

is carried to the gastric glands and stimulates the glands to secrete HCL in the response to food in the stomach

63

Secretin

released by the small intestine, when acidic chyme enters from the stomach
-secretion stimulates the secretion of an alkaline bicarbonate solution form the pancreas that neutralizes the acidity of the chyme

64

Cholecystokinin

is released by the small intestine in response to the presence of fats and cause the contraction of the gallbladder and release of bile into small intestine

65

Bile

not a hormone but is involved in the emulsification and digestion of fats

66

Pineal Gland

tiny structure at the base of the brain that secretes the hormone melatonin

67

melatonin

the role in humans is unclear but it is believed to play a role in regulation of the CIRCADIAN RHYTHM
-secretion is relegated by dark and light cycles