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Physiology II > Chapter Seven - Endocrine Glands > Flashcards

Chapter Seven - Endocrine Glands Flashcards

1
Q

Thyroid gland consists of

A

Two lobes of endocrine tissue joined in the middle by narrow portion of gland

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2
Q

Follicular cells

A

Arranged into hollow spheres
-forms functional unit called a follicle
-lumen filled with colloid

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3
Q

Lumen of follicular cells serves as

A

Extracellular storage site for thyroid hormone

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4
Q

Secretion of TH

A

Produce two iodine containing hormones derived from amino acid tyrosine

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5
Q

C cells

A

Secrete peptide hormone calcitonin

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6
Q

Thyroid gland

A

-synthesis, storage, secretion of thyroid hormone

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7
Q

Basic ingredients involved in synthesis, storage and secretion of thyroid hormone

A

-tyrosine
-iodine

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8
Q

Tyrosine

A

Synthesized in sufficient amounts by body

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9
Q

Iodine

A

Obtained from dietary intake

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10
Q

All steps of synthesis occur on

A

Thyroglobulin molecules within colloid

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11
Q

Tyrosine contains thyroglobulin is exported from

A

Follicular cells into colloid by exocytosis

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12
Q

Thyroid captures iodine form blood and

A

Transfers it into colloid by iodine pump

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13
Q

Within colloid iodine…

A

Attaches to tyrosine

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14
Q

Coupling process occurs between

A

Iodinated tyrosine molecules to from thyroid hormones

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15
Q

Thyroid gland storage

A

-thyroid hormones remain in colloid until they are split off and secreted
-usually enough thyroid hormone stored to supply body’s needs for several months

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16
Q

Thyroid gland secretion

A

-follicular cells phagocytize thyroglobulin laden colloid
-process frees T3 and T4 to diffuse across plasma membrane into blood

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17
Q

Amine hormone

A

2 tyrosines

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18
Q

Lipophilic

A

Transported on plasma protein
-thyroxine binding globulin

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19
Q

Thyroid hormones contain

A

Iodine

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20
Q

T4 and T3 percentages

A

4- 90%
3- 10%

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21
Q

Target cells cleave iodine atom from

A

T4
-mainly liver and kidney
-T3 is four times as potent at T4

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22
Q

Where are receptors for thyroid hormones

A

In nuclei of most cells in body
-widespread actions

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23
Q

Major actions of thyroid hormone

A

-metabolic rate and heat production
-sympathomimetic
-growth and CNS development

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24
Q

Thyroid hormone made up of

A

-amine hormone
-Lipophilic
-iodine

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25
Effects of thyroid hormone
-main determinant of basal metabolic rate -inc target cell responsiveness to catecholamines -normal development of ns -essential for normal growth
26
Thyroid gland: basal metabolic rate
-stimulates Na/K ATPase -heat generated in glycolysis (glucose to ATP) -calorigenic action
27
Thyroid gland: inc target cell responsiveness to catecholamines
-permissive action -inc heart rate and force of contraction
28
Inc b adrenoceptors on heart
-inc heart rate and force of contraction -thyroid gland
29
absence of T3 and T4 during fetal life
Congenital hypothyroidism -poorly developed ns and severely compromised -lack of iodine in pregnant mother
30
Thyroid gland: essential for normal growth
-stimulate GH release and IGF-1 production -enhances effects of GH and IGF-1 on target cells
31
TSH
Tropic hormone
32
Absence of TSH
Thyroid gland atrophy
33
Excess of TSH
Thyroid gland hypertrophy and hyperplasia -goitre
34
TSH regulates
Many steps in thyroid hormone synthesis and release
35
Secretion of thyroid gland is regulated by
Negative feedback system -between hypothalamic TRH, anterior pituitary TSH and thyroid gland T3 and T4
36
Causes of Hypothyroidism
Causes: -primary failure of thyroid gland -secondary to a deficiency of TRH, TSH or both -inadequate dietary supply of iodine
37
Cretinism
Results from hypothyroidism from birth -CNS effect
38
Myxedema
Hypothyroidism -term often used for hypothyroidism in adults -mucopolysaccharides accumulate under skin -deem
39
Anterior pituitary signals
thyroid gland by inc thyroid stimulating hormone
40
Thyroid gland signals
Anterior pituitary by secreting thyroid hormone -decreses
41
Symptoms of hypothyroidism
-inc sensitivity to cold -weight gain -easily fatigued -slow weak pulse -impaired mental function
42
Treatment of hypothyroidism
Replacement hormone therapy -dietary iodine
43
Goitres
Overstimulated thyroid gland with TSH
44
Goiters treatment
-exogenous thyroid hormone -dietary iodine if deficiency is cause
45
Graves’ disease
Autoimmune disease -hyperthyroidism -produces TSI rather than TSH
46
Symptoms of hyperthyroidism
-heat intolerance -weight loss and weakness -inc appetite -inc sns activity
47
Inc sns activety
Anxiety, tremors, inc heart rate
48
Treatment of hyperthyroid ism
-surgical removal of a portion of the thyroid -radioactive iodine -anti thyroid drugs
49
Primary failure of thyroid gland (plasma concentration of relevant hormones, and goitre presen, hypo or hyper?)
- Dec T3 and T4 - inc TSH - goiter present - hypothyroidism
50
Secondary to hypothalamic or anterior pituitary failure (plasma concentration of relevant hormones, and goitre presen, hypo or hyper?)
- Dec T3 and T4 - Dec TRH and TSH - no goiter -hypothyroidism
51
Lack of dietary iodine (plasma concentration of relevant hormones, and goitre presen, hypo or hyper?)
- Dec T3 and T4 - inc TSH - goiter present - hypothyroidism
52
Abnormal presence of long acting thyroid stimulator (plasma concentration of relevant hormones, and goitre presen, hypo or hyper?)
-inc T3 and T4 - Dec TSH -goiter present -hyperthyroidism
53
Secondary to excess hypothalamic or anterior pituitary secretion (plasma concentration of relevant hormones, and goitre presen, hypo or hyper?)
-inc T3 and T4 -inc TRH and TSH -goiter present -hyperthyroidism
54
Hypersecreting thyroid tumour (plasma concentration of relevant hormones, and goitre presen, hypo or hyper?)
-inc T3 and T4 -Dec TSH -goiter not present -hyperthyroidism
55
Adrenal glands found
Embedded above each kidney in a capsule of fat
56
Adrenal glands are composed of two endocrine organs
Adrenal cortex and adrenal medulla
57
Adrenal cortex
Outer portion -secretes steroid hormones
58
Adrenal medulla
Inner portion -secretes catecholamines (E and NE)
59
Adrenal cortex consists of three layers…
-zone glomerulosa -zone fasciculata -zone reticularis
60
Zone glomerulosa
Outermost layer -aldosterone
61
Zone fasciculata
Middle and largest portion -cortisol (mainly) -DHEA
62
Zone reticularis
Inner most zone -DHEA -cortisol
63
Types of adrenal steroids
-mineralocorticoids -glucocorticoids -sex hormones
64
Mineralocorticoids
-mainly aldosterone -influence mineral balance, specifically Na and K balance
65
Glucocorticoids
-primarily cortisol -major role in glucose metabolism as well as in protein and lipid metabolism
66
Sex hormones
-identical or similar to those produced by gonads -most abundant and physiologically important is dehydroepinadosterone or DHEA (male sex hormone)
67
Adrenal glands cortex are all
Cholesterol based hormones -hydrophobic -carried by plasma proteins in blood
68
Cortisol is bound to
Corticosteroid binding globulin
69
Aldosterone and DHEA is bound to
Albumin
70
Mineralocorticoids major effects on Na and K balance
-aldosterone is essential for life -principal action sit is distal and collecting tubules of the kidney
71
Without aldosterone a person
Dies within two days without it from circulatory shock
72
Aldosterone
Principal action site is on distal and collecting tubules of the kidney
73
Aldosterone secretion is increased by
Renin angiotensin aldosterone system -Dec na -fall in bp -rise in plasma K
74
Aldosterone is independent of
Anterior pituitary control
75
Aldosterone Hypersecretion may be caused by
Hypersecreting renal tumour made up of aldosterone secreting cells
76
Aldosterone Hypersecretion symptoms
Excessive Na retention and K depletion -high blood pressure
77
Addison disease
-autoimmune disease -loss of cortical region Adrenocortical insufficiency
78
Aldosterone deficiency
Hyperkalemia and hyponatremia, hypotension
79
Cortisol deficiency
Poor response to stress -hypoglycemia -lack of permissive action for many metabolic activities
80
Secondary adrenocortical insufficiency
Occurs because of pituitary or hypothalamic abnormality -only cortisol is deficient
81
Steroid hormones are involved in
Glucose metabolism -protein and fats
82
Glucocorticoids
Also known as corticosteroids
83
Most abundant steroid hormone found in adrenal glands
Cortisol
84
Cortisol stimulates
Hepatic gluconeogenesis -glucose form non carbohydrate sources (amino acids)
85
Cortisol inhibits
Glucose uptake and use by many tissues -increase plasma glucose *not in the brain
86
Cortisol stimulates (in many tissues)
Protein degradation, especially muscle
87
Cortisol facilitates
Lipolysis -fatty acid increase in blood
88
Cortisol displays a characteristic
Diurnal rhythm -secretion Negative feedback involving hypothalamic CRH and pituitary ACTH
89
Control of cortisol secretion: increase of stress interplays with diurnal rhythms
Stress goes to -hypothalamus -CRH -anterior pituitary -ACTH -adrenal cortex -cortisol
90
Permissive actions of glucocorticoids
-cortisol permits catecholamines to induce vasoconstriction -cortisol and catecholamines induce vasoconstriction to prevent circulatory shock in stressful situation
91
Cushing syndrome
Cortisol Hypersecretion -excessive amount of CRH and ACTH -adrenal tremor secrete cortisol without ACTH -ACTH secreting tumours located other places than pituitary
92
Symptoms related to Cushing’s syndrome
-hyperglycaemia -redistribution of fat -muscle weakness -osteoporosis -immunosuppression -hypertension -think legs, arms, fat on truck and face -red cheeks
93
Treatment for Cushing syndrome
Surgical removal of pituitary tumour, or adrenalectomy
94
Dehydroepiandrosterone or DHEA
-only adrenal sex hormone that has any biological importance -driven by ACTH -over powered by testicular tester one in males
95
DHEA is physiologically significant in females
-growth of pubic and auxiliary hair -enhancement of pubertal growth spurt -development and maintenance of female sex drive
96
Adrenogential syndrome
Adrenal androgen Hypersecretion -cortisol insufficiency inc ACTH—> inc DHEA -DHEA inhibits gonadotropins—> sterile
97
Adrenogenital syndrome in adult females
-male like body hair -depending of voice, more muscular arms and legs -breasts become smaller, menstruation may stop
98
What relieves masculinization
Glucocorticoid therapy
99
Adrenogenital syndrome - newborn females
Have male type external genitalia
100
Adrenogenital syndrome - prepubertal males
Precocious peduopuberty
101
Adrenogenital syndrome - adult males
No apparent affect
102
Adrenal medulla is a modified part of
Sympathetic nervous system -primary stimulus is stress
103
Adrenal medulla releases
Catecholamines -80% epinephrine -20% norepinephrine
104
Epinephrine or adrenaline
Reinforce SNS -maintenance of arterial blood pressure -increases blood glucose and blood fatty acids
105
Process of epinephrine increasing blood glucose and blood fatty acids
-gluconeogenesis in liver -glycogenolysis in liver and skeletal msucle -inhibit insulin secretion -inc glucagon secretion
106
Stress
Nonspecific response of body to any factor that overwhelms homeostasis
107
Stressor
Any noxious stimulus that brings about the stress response
108
Physical stressors
Hold or cold trauma
109
Chemical stressors
Reduced O2
110
Physiological stressors
Exercise, pain
111
infectious stressors
Bacterial
112
Emotional stressors
Anxiety, sorrow
113
social stressors
Lifestyle changes
114
Stress response is coordinated by
Hypothalamus
115
Generalized stress response
-SNS and epinephrine release -activation of CRH-ACTH-cortisol -inc blood glucose and fatty acids -blood volume and bp
116
CRH-ACTH-cortisol
Mobilizes energy stores and metabolic building blocks for use as needed -inc blood glucose, amino acids, fatty acids
117
Intermediary metabolism or fuel metabolism
Includes reaction involving the degradation, synthesis, and transformation of proteins, carbohydrates and fats
118
Anabolism
Buildup of synthesis of larger organic Marco molecules from small organic subunits
119
Catabolism
Breakdown or degradation of large, energy rich, organic molecules within cells
120
Two levels of breakdown
-hydrolysis of large cellular molecules into smaller subunits -oxidation of smaller subunits to yield energy for ATP production
121
Insulin and glucagon
Most important hormones in regulating fuel metabolism
122
B beta cells
Site of insulin synthesis and secretion
123
Alpha cells
Produce glucagon
124
Delta cells
Pancreatic site of somatostatin synthesis
125
PP cells
Least common islet cells -secrete pancreatic polypeptide
126
Insulin is a ___ hormone
Anabolic
127
Secretion of insulin is increased during
Absorptive state -blood glucose concentration is a major stimulus
128
Insulin promotes cellular uptake of
-glucose -fatty acids -amino acids
129
Insulin action on glucose, fatty acids, amino acids
G—> glycogen F—-> triglycerides A—-> proteins
130
Diabetes mellitus
-most common endocrine disorder -elevated blood glucose levels, glucose in urine
131
Type 1 diabetes
10% Lack of insulin secretion
132
Type 2 diabetes
90% -normal or even increased insulin secretion -reduced sensitivity of insulins target cells
133
Polyuria
-classic sign of diabetes mellitus -large urine volume production due to osmolarity -sweet urine

Physiology II (12 decks)

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