Chapter 18 Flashcards

1
Q

Exocrine glands

A

Secrete their products into ducts that carry the secretions into body cavities, the lumen of an organ, or the outer surface of the body

include sweat glands, oil glands, mucus, and digestive glands

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2
Q

Endocrine glands

A

Secrete their products into the interstitial fluid surrounding the secretory cells rather than into ducts who then diffuse into blood capillaries then blood carries them to target cells throughout the body

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3
Q

What does the endocrine glands include?

A

Pituitary, thyroid, parathyroid, adrenal and pineal glands

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4
Q

Down-regulation

A

If a hormone is present in excess the number of target cell receptors decrease

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5
Q

Up regulation

A

When a hormone is deficient the number of receptors may increase

making the target cell more sensitive to a hormone

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6
Q

What other organs can secrete hormones?

A

Hypothalamus
thymus
pancreas
ovaries
testes
kidneys
stomach
liver
small intestine
skin
heart
adipose tissue
placenta

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7
Q

Circulating hormones

A

Pass from the secretory cells that make them into interstitial fluid and then into the blood

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8
Q

Local hormones

A

Act locally on neighbouring cells or on the same cell that secreted them without entering the bloodstream

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9
Q

Paracrines

A

Local hormones that act on neighbouring cells

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10
Q

Autocrines

A

Hormones that act on the same cell that secreted them

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11
Q

What are the three lipid soluble hormones?

A
  1. Steroid hormones
  2. Thyroid hormones
  3. Nitric oxide
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12
Q

Steroid hormones are derived from what?

A

Cholesterol

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13
Q

What is synthesized by attaching iodine to the amino acid tyrosine?

A

Thyroid hormones T3 and T4

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14
Q

What lipid soluble hormone is both a hormone and a neurotransmitter?

A

Nitric oxide (NO)

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15
Q

What are the three water soluble hormones?

A
  1. Amine hormones
  2. Peptide and protein hormones
  3. Eicosanoid hormones
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16
Q

How are Amine hormone synthesized?

A

By decarboxylating and otherwise modifying certain amino acids they are called amines because they retain an amino group

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17
Q

What are some examples of peptide hormones and protein hormones?

A

Peptide: antidiuretic and oxytocin
Protein: Growth hormone and insulin

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18
Q

What’s an example of Glycoprotein hormones?

A

Thyroid stimulating hormone

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19
Q

What are the two major types of Eicosanoids?

A

Prostaglandins and leukotrienes

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20
Q

How do water soluble hormone molecules circulate in the blood plasma?

A

In a “free” form

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21
Q

How do you lipid soluble hormone molecules move through the blood?

A

Via transport proteins

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22
Q

What are the three functions of the transport protein?

A
  1. They make lipid soluble hormones temporarily water soluble thus increasing their solubility in blood
  2. They retard passage of small hormone molecules through the filtering mechanism in the kidneys thus slowing the rate of hormone loss in the urine
  3. They provide a ready reserve of hormone already present in the bloodstream
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23
Q

Free fraction

A

The .1 to 10% of the molecules of lipid soluble hormones that are not bound to a transport protein that diffuse out of capillaries, bind to receptors and trigger responses

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24
Q

First messenger

A

When a water soluble hormone binds to its receptor at the outer surface of the plasma membrane

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25
Q

Second messenger

A

The first messenger causes production of the second messengers inside the cell where specific hormone stimulated responses take place

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26
Q

What is a common second messenger?

A

Cyclic adenosine monophosphate

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27
Q

Permissive affect

A

When a hormone will only work if there was Recent exposure from a second hormone

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28
Q

Synergistic effect

A

When the effect of two hormones acting together is greater than the sum of their individual effects

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29
Q

Antagonistic effects

A

When one hormone opposes the actions of another hormone the two hormones have an antagonistic effect

30
Q

Control of hormone secretion

A

The release of most hormones occurs in short bursts with little or no secretion between bursts when stimulated an endocrine gland will release its hormone in more frequent bursts increasing concentration of the hormone in the blood

31
Q

What are the three things hormone secretion is regulated by?

A
  1. Signals from the nervous system
  2. Chemical changes in the blood
  3. Other hormones
32
Q

What are the other words and terms for pituitary gland?

A

Hypophysis and “master” endocrine gland

33
Q

What gland controls the “master” gland?

A

Hypothalamus

34
Q

Infundibulum

A

Stalk connecting the hypothalamus and pituitary

35
Q

Anterior pituitary

A

Also called adenohypophysis

75% of glands weight

Made of epithelial tissue

Two parts: pars distalis and pars tuberalis

36
Q

Posterior pituitary

A

Also called neurohypophysis

Made of neural tissue

Two parts: pars nervosa and pars intermedia

37
Q

What are the five anterior pituitary cells?

A
  1. Somatrophs
  2. Thyrotrophs
  3. Gonadotrophs
  4. Corticotrophs
  5. Lactotrophs
38
Q

Somatrophs secrete what hormones?

A

Growth hormone and somatropin

39
Q

Thyrotrophs secret what hormone?

A

Thyroid-stimulating hormone

40
Q

Gonadotrophs secret what hormone?

A

Follicle stimulating hormone and lutenizing hormone

41
Q

Lactotrophs secrete what hormone?

A

Prolactin

42
Q

Corticotrophs secret what hormone?

A

Adrenocorticotropic hormone (ACTH)/ corticotropin and melanocyte stimulating hormone (MSH)

43
Q

What is prolactin inhibiting hormone?

A

Dopamine

44
Q

What is growth hormone inhibiting hormone?

A

Somatostatin

45
Q

Hypophyseal portal system

A

Blood flows from capillaries in the hypothalamus into portal veins that carry blood to capillaries of the anterior pituitary

Allows communication between hypothalamus and anterior pituitary

Link between nervous system and endocrine system

46
Q

Superior hypophyseal arteries

A

Branches of the internal carotid arteries bring blood into the hypothalamus at the junction of the median eminence of the hypothalamus and the infundibulum and divide into a Capillery network called the primary plexus of the hypophyseal portal system

47
Q

Neurosecretory cells

A

Clusters of neurons above the optic Chiasm

48
Q

Tropic hormones

A

Anterior pituitary hormones that act on other endocrine glands

49
Q

How does GH exert its growth promoting affects indirectly through small protein hormones?

A

With insulin-like growth factors (IGFs) / somatomedins

50
Q

What are the specific functions of insulin like growth factors(IGFs)?

A
  1. Increase growth of bones and soft tissues
  2. Enhance lipolysis
  3. Decrease glucose uptake
51
Q

How is growth hormone regulated by GHRH and GHIH?

A
  1. GHRH is secreted by the hypothalamus. Due to Hypoglycemia, decrease blood levels of fatty acids, increase blood levels of amino acids, deep sleep, increased activity of the sympathetic nervous system, and other hormones including testosterone, estrogen, thyroid, hormones and ghrelin
  2. Once secreted, GHRH enters the hypophyseal portal system and flows to the anterior pituitary where it stimulates somatotrophs to secrete GH
  3. GH Acts directly on various cells to promote certain metabolic reactions in liver, bone, skeletal muscle, and cartilage GH is converted to IGF’s which intern promote growth of bone, skeletal muscle, and other tissues
  4. Elevated levels of GH and IGFs inhibit release of GHRH and GH
  5. GHIH is secreted by the hypothalamus
  6. GHIH enters the hypophyseal portal system and flows to the anterior pituitary where it prevents the somatotrophs from secreting GH by interfering with the signaling pathway used by GHRH
52
Q

Adrenocorticotropic hormones

A

Secreted by Corticotrophs

Controls the production and secretion of cortisol and other glucocorticoids by the cortex of the adrenal glands

53
Q

Stored hormones In posterior pituitary?

A

Oxytocin and anti diuretic

54
Q

Thyroid gland

A

Composed of right and left lobes connected by the Isthmus, anterior to the trachea

Made of thyroid follicles, follicular cells, and a basement membrane

Produces thyroxine and triiodothyronine

Paraflicular cells produce calcitonin

55
Q

Steps for synthesis and secretion of t3 and t4?

A
  1. Iodide trapping
  2. Synthesis of thyroglobulin
  3. Oxidation of iodide
  4. Iodination of tyrosine
  5. Coupling of t1 and t2
  6. Pinocytosis and digestion of colloid
  7. Secretion of thyroid hormones
  8. Transport in the blood
56
Q

Functions of thyroid hormones?

A
  1. Increase basal metabolic rate
  2. Enhance actions of catecholamines
  3. Regulate development and growth of nervous tissue and bones
57
Q

Calcitonin

A

Produced by parafollicular cells of the thyroid gland

Decrease the level of calcium in the blood by inhibiting the action of osteoclast

58
Q

Parathyroid gland

A

One superior and one inferior the parathyroid glands are attached to each lateral thyroid lobe =4

Chief cells produce parathyroid hormone

Oxyphil cells don’t produce anything normally

59
Q

Parathyroid hormone

A

Major regulator of calcium, magnesium and phosphate levels

Elevate bone resorption

Slows the rate at which calcium and magnesium are lost from the blood into the urine increases loss of HPO 42-

Promote formation of calcitriol

60
Q

Adrenal glands

A

Superior to each kidney

Consists of adrenal cortex and adrenal medulla

Produces steroid hormones: Norepinephrine, epinephrine, dopamine

61
Q

Adrenal cortex

A

Zona glomerulosa: mineralcorticoids

Zona fasciculata: glucocorticoids

Zona reticularis: androgens

62
Q

Mineralcorticoids

A

Aldosterone

Regulates homeostasis of sodium ions and potassium ions and also promote excretion of hydrogen ions in the urine

63
Q

The renin angiotensin-aldosterone (RAA) pathway That controls secretion of aldosterone

A
  1. Stimuli that initiate the renin angiotensin aldosterone pathway include dehydration, sodium deficiency, or haemorrhage
  2. These conditions cause a decrease in blood volume
  3. Decrease blood volume leads to decrease blood pressure
  4. Lower blood pressure stimulate certain cells of the kidneys call juxtaglomerular cells to secret the enzyme renin
  5. Renin in blood increases
  6. Renin converts angiotension a plasma protein produced by the liver into angiotension 1
  7. Blood containing increase levels of angiotension one circulates in the body
  8. As blood flows through capillaries particularly those of the lungs the enzyme angiotensin-converting enzyme converts angiotension one into the hormone angiotension two
  9. Blood level of angiotension 2 increases
  10. Angiotension two stimulates the adrenal cortex to secrete aldosterone
  11. Blood containing increase levels of aldosterone circulates to the kidneys
  12. In the kidneys aldosterone increases reabsorption of sodium which in turn causes reabsorption of water by osmosis as a result less water is lost in the urine aldosterone also stimulates the kidneys to increase the secretion of potassium and hydrogen into the urine
  13. Increased water reabsorption by the kidneys, blood volume increases
  14. As blood volume increases blood pressure increases to normal
  15. Angiotension 2 also stimulates contraction of smooth muscle in the walls of arterrials the resulting vaso construction of the materials increases blood pressure and thus helps raise blood pressure to normal
64
Q

Effects of glucocorticoids?

A
  1. Protein breakdown
  2. Glucose formation
  3. Lipolysis
  4. Resistance to stress
  5. Anti-inflammatory
  6. Depression of immune responses
65
Q

Androgens

A

Testosterone and estrogen

66
Q

Adrenal medulla

A

Hormone producing cell called chromaffin cells synthesize epinephrine and norepinephrine

67
Q

Pancreas

A

Cells called acini that produce digestive enzymes
With clusters of pancreatic islets

68
Q

Cells types of the pancreatic islets

A
  1. Alpha/ A cells produce glucagon
  2. Beta/ B cells produce insulin
  3. Delta/ D cells somatostatin
  4. F cells secret pancreatic polypeptide
69
Q

Insulin secretion is also stimulated by

A
  1. Acetylcholine the neurotransmitter liberated from axon terminals
  2. Amino acids arginine and Lusine which would be present in the blood at higher levels after a protein containing meal
  3. Glucose dependent insulinotropic peptide
70
Q

Glucagon is stimulated by

A

Increase activity of a sympathetic division of the ANS

A rise in blood amino acid if blood glucose level is low