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Physiology II - HLSC 128 > Chapter 7- The Endocrine Glands > Flashcards

Chapter 7- The Endocrine Glands Flashcards

1
Q

What is the thyroid gland?

A

Two lobes of endocrine tissue joined in missile by narrow portion of gland

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2
Q

What are the functional unit of the Thyroid?

A

Follicular cells (follicle)

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3
Q

How are follicular cells arranged in the thyroid gland?

A

Into hollow spheres which form a follicle

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4
Q

What is the lumen of follicular cells filled with?

A

Coloid

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5
Q

What is the function of coloid in follicular cells?

A

Serves as extracellular storage for thyroid hormone

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6
Q

What kind of hormones does the thyroid produce?

A

Two iodine-containing hormones derived from amino acid tyrosine

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7
Q

What are the 2 hormones that the thyroid produces?

A

Tetraiodothyronine (T4 or thyroxine)
Triiodothyronine (T3)

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8
Q

What neuroendocrine cells does the thyroid have?

A

C cells

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9
Q

What do C cells secrete?

A

Peptide hormone called Calcitonin

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10
Q

What is the thyroid gland responsible for?

A

Synthesis, storage and secretion of thyroid hormone

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11
Q

What are the 2 basic ingredients of thyroid hormone?

A
  1. tyrosine (synthesised by body)
  2. Iodine (dietary intake)
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12
Q

Where does synthesis of TH occur?

A

On thyroglobulin molecules with colloid

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13
Q

How does tyrosine enter the colloid?

A

Tyrosine-containing thyroglobulin is exposed from follicular cells into colloid via exocytosis

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14
Q

How does the iodine enter the colloid?

A

via Iodine pump after thyroid captures iodine in the blood

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15
Q

What happens to tyrosine and iodine in the colloid?

A

Iodine attaches to tyrosine and forms thyroid hormones

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16
Q

How does thyroid store thyroid hormone?

A

Remind in colloid
-Until split off and secreted
-Enough is stored to supply body for several months

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17
Q

How are thyroid hormones secreted?

A

Follicular cells phagocytise thyrogolbin-laden colloid which frees T3 and T4 to diffuse into blood

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18
Q

What kind of hormones is thyroid hormone?

A

Amine
-has 2 tyrosines
-Has iodine

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19
Q

What is the chemical nature of thyroid hormone?

A

Lipophilic
-Transported by plasma protein

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20
Q

What percent of each thyroid hormone is produced?

A

T4 - 90%
T3 - 10%

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21
Q

Why is T3 produced less than T4?

A

because T3 is four times more potent than T4

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22
Q

Where are the target cells that cleave iodine to form T4?

A

Mainly in the liver and kidney

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23
Q

What plasma protein does T4 bind with?

A

Thyroxine-binding globulin

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24
Q

Where are receptors for thyroid hormones found?

A

Nuclei of most of the cells in the body
-allows for widespread action

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25
Q

What are thyroid hormone major actions?

A
  1. basal Metabolic rate and heat production
  2. Sympathomimetic (permissive action)
  3. Growth and CNS development
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26
Q

How does thyroid hormone determine basal metabolic rate?

A

-Stimulates Na/K ATPase
-Generates heat during glycolysis
-Calorigenic action

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27
Q

What is thyroid hormone’s sympathomimetic effect?

A

Increases target-cell responsiveness to catecholmines

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28
Q

How does thyroid hormone have a sympathomimetic effect?

A

Permissive action
Increases HR and force of contraction
-Increase b-adenorecptors on heart

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29
Q

How does thyroid hormone effect nervous system development?

A

Hormones help develop the nervous system properly
-lack of hormone can affect growth

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30
Q

What happens if there is an absence of T3 and T4 during fetal life?

A

Congenital hypothyroidism
(cretinism)

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31
Q

What is the effect of Congenital hypothyroidism?

A

poorly developed NS and severely compromised intellectual function

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32
Q

What can cause Congenital hypothyroidism ?

A

Lack of iodine in pregnant mother

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33
Q

How is thyroid hormone essential for normal growth?

A

Stimulates Gh release and IGF-1 production
Enhances effects of GH and IGF-1 on target cells

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34
Q

What is the function of TSH?

A

Regulates steps in thyroid hormone synthesis and release

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35
Q

What happens if there is an absence of TSH?

A

Thyroid gland atrophy

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36
Q

What happens if there is an excess of TSH?

A

Thyroid gland hypertrophy and hyperplasia causing a Goiter

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37
Q

What regulates thyroid gland secretion?

A

A negative-feedback system
-Hypothalmic TRH
-Anterior pituitary TSH
-Thyroid gland T3 and T4

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38
Q

What are two main categories of abnormalities of the thyroid gland?

A
  1. Hypothyroidism
  2. Hyperthyroidism
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39
Q

What is th term often used for Hypothyroidism in adults?

A

Myxedema

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40
Q

What does Myxedema cause?

A

Mucopolysaccharides accumulate under the skin forming an edna

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41
Q

What are the symptoms of Hypothyroidism??

A

Increased sensitivity to cold -calorigenic
Weightgainc–calorigenic
Easily fatigued
Slow weak pulse –cardiac
Impaired mental function

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42
Q

How is Hypothyroidism treated?

A

-replacement hormone therapy
-Dietary iodine

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43
Q

What may occur with hypothyroidism?

A

Goiters
(Too much TSH)

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44
Q

How are goiters treated?

A

-Exogenous thyroid hormone
-Dietary iodine if its a deficiency causing it

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45
Q

What is the most common cause of hyperthyroidism ?

A

Grave’s disease
(autoimmune disease)

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46
Q

What is Grave’s disease?

A

Body incorrectly produces thyroid-stimulating immonoglobulines which act like TSH

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47
Q

What is a prominent characteristic of those with Grave’s disease?

A

Exophthalmos
-Protruding eyes

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48
Q

What are symptoms of hyperthyroidism?

A

Heat intolerance
Weight loss including skeletal muscle
Increased appetite
Increased SNS activity: anxiety, tremors, increased HR

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49
Q

How is hyperthyroidism treated?

A

-Surgical removal of portion of the over-secreting thyroid
-radioactive iodine
-Antithyroid drugs

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50
Q

What are adrenal glands?

A

Glands embedded above each kidney in a capsule of fat

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51
Q

What are the two exocrine organs composing the Adrenal glands?

A
  1. Adrenal cortex
  2. Adrenal medulla
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52
Q

What is the adrenal cortex?

A

Outer portion

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53
Q

What doe the adrenal cortex secrete?

A

Steroid hormones

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54
Q

What does the adrenal medulla secrete?

A

catecholamines
(epinephrine and NE)

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55
Q

What are the 3 zones/layers of the adrenal cortex? (outmode to innermost)

A

Zona golerulosa
Zona fasciculata
Zona reticularis

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56
Q

What does the Zona glomerulosa secrete?

A

Aldosterone
(outermost layer)

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57
Q

What does the Zona fasciculata secrete?

A

Main source of Cortisol
DHEA
(middle layer)

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58
Q

What does the Zona reticularis secrete?

A

DHEA
some cortisol
(innermost layer)

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59
Q

What is the largest portion/layer of the adrenal cortex?

A

Zona fasciculata

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60
Q

What are the 3 categories of adrenal steroids?

A
  1. Mineralocorticoids
  2. Glucocorticocoids
  3. Sex hormones
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61
Q

What are Mineralocorticoids?

A

Influence mineral balance (Na and K)
Mainly aldosterone

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62
Q

What are glucocorticoids?

A

Major role in glucose metabolism and protein and lipid matabolism
Mainly cortisol

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63
Q

What are sex hormones?

A

Identical or similar to those produced by the gonads
-Most important is DHEA

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64
Q

What is DHEA?

A

dehydroepiandosterone
(male “sex” hormone)

65
Q

What are all adrenal cortex hormones based from?

A

All cholesterol-based

66
Q

What is the chemical nature of cholesterol-based hormones?

A

Hyrophopic
Carried by plasma proteins in blood

67
Q

What plasma protein is Cortisol bound to?

A

Corticosteroid-binding globulin (transcortin)

68
Q

What plasma protein is aldosterone and DHEA bound to?

A

Albumin

69
Q

what is aldosterone’s principal action site?

A

Distal and collecting tubules of the kidney

70
Q

What increases aldosterone secretion?

A

Renin-angiotensin-aldosterone system

71
Q

How is the RAS triggered?

A

When blood sodium levels drop or potassium levels rise Renin is released by the adrenal glands

72
Q

What s aldosterone’s function?

A

Help kidney’s retain sodium and excrete potassium

73
Q

What part of the brain does aldosterone act independently of?

A

The anterior pituitary

74
Q

What are 2 main disorders of adrenocortical function?

A
  1. Aldosterone hypersecretion
  2. Adrenoctical insufficiency
75
Q

What can cause aldosterone hyper secretion?

A

-Hypersecreting adrenal tumour made of adolsterone-secreting cells
-Inapropriately high activity of RAS

76
Q

What does a hypersecreting aldosterone tumour cause?

A

Primary hyperaldosteronism aka Conn’s syndrome

77
Q

What does inappropriately high activity of the RAS cause?

A

Secondary hyperaldosteronism

78
Q

what are symptoms of Aldosterone hyper secretion?

A

-Excessive Na retention and K depletion
-HIGH blood pressure

79
Q

What causes Primary adrenocortical insufficiency?

A

Addison’s disease
Autoimmune disease (most common)
Loss of cortical region
-Leads to aldosterone and cortisol deficiencies

80
Q

What does an aldosterone deficiency cause?

A

-Hyperkalemia and hyponatremia, hypotension

81
Q

What does a cortisol deficiency cause?

A

Poor response to stress
Hypoglycemia
Lack of permissive action for many metabolic activities

82
Q

Why does secondary adrenocortical insufficiency occur?

A

Occurs because of pituitary or hypothalamic abnormality

83
Q

What hormone does secondary adrenocortical insufficiency cause a deficiency of?

A

ONLY CORTISOL
-No hypothalamic hormones to trigger the release of it

84
Q

What is the most abundant Glucocorticoid? aka Corticosteroids

A

Cortisol

85
Q

What does cortisol stimulate?

A

-Hepatic gluconeogenesis
-Protein degradation in tissue especially muscle

86
Q

What is Hepatic gluconeogenesis

A

the process where the liver makes new glucose molecules from non-carbohydrate sources
e.g; amino acids

87
Q

What does Cortisol inhibit?

A

Glucose uptake and use by many tissues (not the brain tho)
-Increases plasma glucose

88
Q

What does cortisol facilitate?

A

Lipolysis
-Fatty acid increases in blood

89
Q

What emotion does cortisol play a key role in adapting to?

A

Stress

90
Q

What is cortisol secretion regulated by?

A

negative-feedback loop involving CRG and pituitary ACTH

91
Q

Cortisol displays a charecteristic _______ _______

A

Dinural Rhythm
-Cortisol levels are highest in the morning and lowest at night

92
Q

Cortisol is a permissive action hormone, what hormones requires its presence?

A

Permits catecholamines, epinephrine

93
Q

What does epinephrine require cortisol for?

A

To induce vasoconstriction to prevent circulatory shock in stressful situations

94
Q

What is the same for Cortisol hyper secretion?

A

Cushing’s syndrome

95
Q

What causes Cushing’s syndrome?

A
  1. Overstimulation of adrenal cortex by excessive amounts of CRH and ACTH (Cushing’s disease -most common)

2, Adrenal tumours that secrete cortisol independent of ACTH

  1. ACTH-secreting tumours located in places other than the pituitary
96
Q

What does Cushing’s syndrome cause?

A

Hyperglycemia -diabetes mellitus levels
Redistribution of fat
Muscle weakness
Osteoperosis
Immunosuppression
Hypertension
Hypercortisolism stratia
Thin legs and arms, fat on trunk and face
Red cheeks

97
Q

How is fat redistributed in Cushing’s syndrome patients?

A

Buffalo hump
Moon face

98
Q

What causes Hypercortisolism-stratia in Cushing’s syndrome patients?

A

Protein breaks down in skin
-Stretch mark-like appearance

99
Q

How is Cushing’s syndrome treated?

A

Depends on the cause:
-Surgial removal of pituitary tumour
-Adrenalectomy

100
Q

What sexes does the adrenal cortex produce sex hormone in?

A

Both

101
Q

What is the name of the adrenal sex hormone with biological importance?

A

DHEA
Dehyroepiandrosterone

102
Q

In males what happens when DHEA is secreted?

A

It is overpowered by testicular testosterone

103
Q

In females when DHEA is secreted?

A

-Causes pubic and axillary hair growth
-Enhances pubertal growth spurt
-Develops and maintains female sex drive

104
Q

What hypothalamic hormone controls DHEA?

A

ACTH
-not gonadotropins FSH and LH

105
Q

What is the name for Adrenal androgen hyper secretion?

A

Adrenogenital syndrome

106
Q

What are symptoms of Adrenogenital syndrome in Adult females?

A

Hirsutism (male like body hair)
Deepening of voice
More muscular arms and legs
Smaller breasts
Menstruation ceases

107
Q

What can cause Adrenogenital syndrome?

A

Cortisol insufficiency
-because it increases ACTH, which stimulates DHEA

108
Q

What does DHEA inhibit?

A

Gonadotropins
-during hyper secretion of DHEA can lead to sterility

109
Q

How is Adrenogenital syndrome treated?

A

Glucocorticoid therapy

110
Q

What are the symptoms of Adrenogenital syndrome in newborn females?

A

Have male-type external genitalia

111
Q

What are symptoms of Adrenogenital syndrome in Prepubertal males?

A

precocious pseudopuberty

112
Q

What are symptoms of adrenogenital syndrome in Adult males?

A

No apparent effect

113
Q

What nervous system is the adrenal medulla a modified part of?

A

The sympathetic nervous system

114
Q

What is the primary stimulus of the adrenal medulla?

A

Stress

115
Q

What hormones does the adrenal medulla release?

A

Catecholamines

116
Q

How much of each catecholamine does the adrenal medulla release?

A

Epinephrine 80%
Norepinephrine 20%

117
Q

Why do the actives of adrenal medulla catecholamine vary?

A

Their activities depend on different adrenergic receptor types
-alpha and beta adrenoceptors

118
Q

What are the functions of Epinephrine?

A

aka Adrenlaline
-reinforces SNS (systemic response to fight or flight)
-Maintains arterial BP
-increases blood glucose and blood fatty acids

119
Q

How does epinephrine increase blood glucose and blood fatty acids?

A

-Stimulates Gbuconeogensis in the liver
-Stimulates glycogenolysis in the liver and skeletal muscles
-Inhibits insulin secretion
-increase glucagon secretion

120
Q

What is a stress response?

A

Pattern of reactions to a situation that threatens homeostasis

121
Q

What is stress?

A

nonspecific response of body to any factor that overwhelms the body’s ability to maintain homeostasis

122
Q

What is a stressor?

A

Any harmful stimulant that brings about the stress response

123
Q

Examples of stressors?

A

Physical – hot/cold, trauma
Chemical – reduced O2
Physiological – exercise, pain ● Infections - bacterial
Emotional – anxiety, sorrow
Social – lifestyle changes

124
Q

What is the stress responses actions coordinated by?

A

Hypothalamus

125
Q

What does a generalised stress response activate?

A

SNS
CRH-ACTH-cortisol system

126
Q

Why does a stress response activate the SNS?

A

Prepare body for fight-or flight response
-Epinephrine

127
Q

Why does a stress response activate the CRH-ACTH-cortisol system?

A

Helps body cope by mobilizing metabolic resources

128
Q

What does a genralized stress response cause?

A

Elevation of blood glucose and fatty acids
Maintaince of blood volume and blood pressure

129
Q

How is blood glucose and fatty acids elevated during a stress response?

A

Insulin decreases
Glucagon increases

130
Q

What is metabolism?

A

All the chemical reactions that occur within the cells of the body

131
Q

What is intermediary/fuel metabolism?

A

Includes reactions involving the degradation, synthesis, and transformation of proteins, carbohydrates, and fats

132
Q

What is anabolism?

A

buildup or synthesis of larger organic macromolecules from small organic subunits
■■■■ —-> █

133
Q

What do anabolism reactions require?

A

ATP energy

134
Q

What do anabolism reactions result in?

A
  1. Manufacture of materials needed by the cell
    2.Storage of excess ingested nutrients not immediately needed for energy
135
Q

What is Catabolism?

A

breakdown or degradation of large, energy-rich organic molecules within cells
█ —-> ■■■■

136
Q

What are the two levels of catabolism breakdown?

A
  1. Hydrolysis of large molecules into smaller subunits
  2. Oxidation of smaller subunits to yield energy for ATP production
137
Q

What hormones are most important in regulation fuel metabolism?

A

Insulin and glucagon

138
Q

What are the endocrine cells of the pancreas called?

A

Islets of Langerhans

139
Q

What are the 4 specific islet cells in the endocrine pancreas?

A
  1. β (beta) cells
  2. α (alpha) cells
  3. δ (delta) cells
  4. PP cells
140
Q

What do β (beta) cells do?

A

Site of insulin synthesis and secretion

141
Q

What do α (alpha) cells do?

A

Produce glucagon

142
Q

What do δ (delta) cells do?

A

Pancreatic site of somatostatin synthesis

143
Q

What are PP cells?

A

Least common islet cell
Secretre pancreatic polypeptide

144
Q

What kind of hormone is Insulin?

A

Anabolic hormone

145
Q

When does the secretion of insulin increase?

A

During absorptive state

146
Q

What is a major stimulus of insulin secretion?

A

Blood glucose concentration

147
Q

What does insulin promote the cellular uptake of?

A

-Glucose
-Fatty acids
-Amino acids
*lowers blood concentration of them

148
Q

What does insulin covert glucose to?

A

Glycogen

149
Q

What does insulin convert fatty acids to?

A

Tryglycerides

150
Q

What does insulin convert amino acids to?

A

Proteins

151
Q

What is the most common endocrine disorder ?

A

diabetes mellitus

152
Q

What is a prominent feature of diabetes mellitus?

A

Elevated blood glucose levels
Glucose in urine

153
Q

What are the 2 major types of diabetes mellitus?

A

Type I
Type II

154
Q

What percentage of people with diabetes mellitus have each type?

A

10% have Type I
90% have Type II

155
Q

What is Type I diabetes?

A

Lack of insulin secretion

156
Q

What is Type II diabetes?

A

Normal or increased insulin secretion
-Insulin’s target cells are less sensitive

157
Q

What is a classic sign of diabetes mellitus?

A

Polyuria
-Large urine volume produced

158
Q

Why does diabetes mellitus cause polyuria?

A

Extra glucose exceeds capacity of nephron to absorb it
● With glucose, stays water=osmotic diuresis, causing “sweet urine”

Physiology II - HLSC 128 (7 decks)

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