HORMONES OF THE ENDOCRINE SYSTEM Flashcards
1
Q
Synthesized in thyrotrophs
A
I. THYROID STIMULATING HORMONE
2
Q
Composed of two non-covalently linked alpha & beta sub-units
A
I. THYROID STIMULATING HORMONE
3
Q
a-unit is identical to
A
FSH, LH & hCG
4
Q
B-unit attaches to
A
thyroid receptors
5
Q
Significance of TSH:
A
- Stimulates growth and vasculature of the thyroid gland
- Uptake and organification of iodine
- Promotes release of stored thyroid hormones
6
Q
Ultrasensitive method for TSH determination
A
Immunoradiometric assay (IRMA)
7
Q
best thyroid function test
A
Immunoradiometric assay (IRMA)
8
Q
Differentiate hypo vs hyperthyroidism
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Immunoradiometric assay (IRMA)
9
Q
LATS (long acting thyroid stimulating substance)
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Immunoradiometric assay (IRMA)
10
Q
detectable in the serum of thyrotoxic patients which imitates the biologic action of TSH
A
LATS (long acting thyroid stimulating substance)
11
Q
GONADOTROPINS
A
LH
FSH
12
Q
• Secreted by the gonadotropic cells
A
Luteinizing Hormone (LH) & Follicle-Stimulating Hormone(FSH)
13
Q
• Control the FSH functional activity of gonads
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Luteinizing Hormone (LH) & Follicle-Stimulating Hormone(FSH)
14
Q
Promotes and maintains the 2nd portion of the menstrual cycle
A
LH in females
15
Q
Cause release of ova from ovarian follicles
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LH in females
16
Q
Transformation of the follicle into the corpus luteum after ovulation
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LH in females
17
Q
Secretion of progesterone by the corpus luteum
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LH in females
18
Q
Responsible for production of testosterone by the Leydig cells of the testes
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LH in males
19
Q
Maturation of spermatozoa requires both
A
LH & FSH
20
Q
Stimulates growth & maturation of ovarian follicles
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FSH in females
21
Q
Promote endometrial changes characteristics of the 1st portion of menstrual cycle
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FSH in females
22
Q
Promotes secretion of estrogen by maturing follicles (in the presence of LH)
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FSH in females
23
Q
Stimulates spermatogenesis
A
FSH in males
24
Q
Stimulates testicular growth production of ABP (androgen binding protein) by the Sertoli cells
A
FSH in males
25
slight inc in FSH: stimulates devt of ovarian follicle
Follicular Phase
26
14th day: inc in LH and ESTROGEN (promotes and maintains ovulation of follicles)
Ovulatory Phase
27
Released ovum is passed thru fallopian tube to be ready for fertilization by the sperm
Ovulatory Phase
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Follicle transforming to corpus luteum
Luteal Phase
29
inc PROGESTERONE
Luteal Phase
30
METHODS FOR DETERMINATION FOR TSH
Commercial RIA kits for both blood (serum or plasma) & urine samples
31
Because of episodic, circadian & cyclic variation in secretion of gonadotropins, clinical evaluation requires determinations in:
Pooled blood samples
Multiple serial blood samples
Timed sample of urine
32
collected in different time intervals, pulled together, measured as one
Pooled blood samples
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now, after 1 hour, another 1 hour/ morning, afternoon, evening
Pooled blood samples
34
1-time testing (cheaper)
Pooled blood samples
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collect sample w/ timed intervals
Multiple serial blood samples
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tested each samples as collected
Multiple serial blood samples
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serial blood collection and testing serial
Multiple serial blood samples
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all blood samples tested (more expensive)
Multiple serial blood samples
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more accurate - average of all results
Multiple serial blood samples
40
secreted by Luteotropin
II. PROLACTIN
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: initiation and maintenance of lactation
Milk let down reflex
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Physiologic increase seen during:
• Pregnancy • Lactation • Post pubertal women
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• Promotes milk production following birth of an infant.
II. PROLACTIN
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• The effect of PRL in males is less understood, although it may cause a
deficiency of male sex hormones.
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PRL • main target tissue: [?] (production of milk)
breast
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• Secreted in circadian fashion
• Increased during sleep
• Lowest at 10am to 12mm
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• Secreted in pulsatile fashion
II. PROLACTIN
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• 3 specimens taken at
20-30 minutes intervals
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Conc varies throughout the day
pulsatile fashion
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PRL Major circulating form:
non-glycosylated monomer
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PRL Other forms:
• “Big" prolactin
• Macroprolactin ("big, big" prolactin)
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Protein attached to a circulating protein
“Big" prolactin
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coupled with immunoglobulin (usually IgG)
Macroprolactin ("big, big" prolactin)
54
PRL Method:
Immunoassay following PEG (polyethylene glycol). extraction and centrifugal ultrafiltration
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PRL Reference values :
• Males : 1-20 ng/ml
• Females : 1-25 ng/ml
• Lactating mothers: 500 ng/ml
• Physiologic increase rarely >200ng/ml
56
39-amino acid peptide hormone (MW 4,500)
III. ADRENOCORTICOTROPIC HORMONE
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ACTH Precursor molecule: (MW 28,500)
POMC or Pro-opiomelanocortin
58
ACTH Half -life:
7 - 12 minutes
59
Controls the secretion of hormones from the adrenal cortex
III. ADRENOCORTICOTROPIC HORMONE
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Regulated by corticotropin-”stress hormone”, releasing hormone from the hypothalamus, and stress can also increase its release.
III. ADRENOCORTICOTROPIC HORMONE
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: bigger than ACTH
Beta-lipotropin
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Beta-lipotropin is cleaved into:
Gamma-lipotropin
Beta-endorphin
63
ACTH is cleaved into:
Melanocyte-stimulating hormone
Corticotropin Intermediate Lipotropin
Melanocyte-stimulating hormone (MSH)
64
Products of the cleavage of POMC:
Lipotropin
Beta-endorphin and Met-enkephalin
Melanocyte-stimulating hormone (MSH)
65
described as having weak lipolytic effects; important as the precursor to beta-endorphin.
Lipotropin
66
Opioid peptides with pain-alleviation and euphoric effects; More resistance to pain
Beta-endorphin and Met-enkephalin
67
Known to control melanin pigmentation in the skin of most vertebrates.
Melanocyte-stimulating hormone (MSH)
68
Aka neurohypophysis
Posterior Pituitary
69
Does NOT synthesize hormones
Posterior Pituitary
70
Secretes Arginine Vasopressin (AVP) and Oxytocin
Posterior Pituitary
71
These hormones are synthesized in the hypothalamus (paraventricular & supraoptic nuclei)
Posterior Pituitary
72
Clinically important hormones of the Posterior Pituitary gland
1. Antidiuretic hormone (ADH)
2. Oxytocin
73
Hypothalamus regulates secretion of ADH based on the body's hydration state.
ADH
74
Primarily allows the kidney to conserve water
ADH
75
Important to osmolality (conc of all particles dissolved)
ADH
76
Conditions associated with AVP secretion
I. Hypothalamic Diabetes Insipidus
II. Nephrogenic Diabetes Insipidus
III. Psychogenic or Primary Polydipsia
IV. Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
77
A.k.a Neurogenic, Central or Cranial diabetes insipidus
I. Hypothalamic Diabetes Insipidus
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Caused by a failure of the pituitary gland to secrete normal amounts of AVP in response to osmoregulatory factors.
I. Hypothalamic Diabetes Insipidus
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Assoc. with neoplastic disease, surgery, head trauma, hypoxia, granulomatous disease, infections and autoimmune dse.
I. Hypothalamic Diabetes Insipidus
80
Failure of the kidney to respond to normal or increased concentration of AVP
II. Nephrogenic Diabetes Insipidus
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Caused by mutations in the AVP receptors and Aquaporin-2 water channels
II. Nephrogenic Diabetes Insipidus
82
Acquired forms: Metabolic disorders, Drugs and Renal disease
II. Nephrogenic Diabetes Insipidus
83
Chronic and excessive intake of water supresses AVP secretion
III. Psychogenic or Primary Polydipsia
84
Causes hypotonic polyuria
III. Psychogenic or Primary Polydipsia
85
Hypothalamic disease affecting the thirst centers of the brain
III. Psychogenic or Primary Polydipsia
86
Plasma AVP concentrations are increased without known stimuli
Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
87
Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Result of:
Malignancy (main); overproduction of AVP
Acute and chronic disease of the CNS
Side effects of drugs
88
In childbirth: causes contraction of uterine muscles and in milk-let down by forcing milk into ducts from the milk glands.
Oxytocin
89
Oxytocin Primary Stimulus
1. Suckling
2. Stretch receptors in the uterus and vaginal mucosa
3. Emotional stress may inhibit lactation
90
- stimulation of the tactile receptors located around the nipples
1. Suckling
91
1. Suckling
Oxytocin + prolactin
92
Post-partum depression
3. Emotional stress may inhibit lactation
93
Synthesized by the pituitary gland
TSH
94
- located near the vocal cord
thyroid gland
95
thyroid hormones:
T3, T4
96
- imp for the synthesis of t3 and t4; mainly absorb from the food we eat
iodine
97
=. Goiter (principal symptom of thyroid problem)
Rock-salt consumption (w/o iodine)
98
Different to TSH; Imitates: stimulates the thyroid gland
LATS
99
Found in px w/ thyrotoxicosis
LATS
100
: extreme production of T3 and T4
thyrotoxicosis
101
Hormones synthesized by the gonads
GONADOTROPINS
102
GONADOTROPINS
Male:
Female:
testes
ovary
103
Important in the production of gametes (ova or sperm)/haploid cell (containing 1 chromosome)
GONADOTROPINS
104
: follicles has already released egg/ovum
Luteal phase
105
: - structure w/in the ovary where the egg cell/ova develops; storage of egg cells
Follicle
106
- thousands during menstrual cycle
Follicle
107
- when an egg matures, it breaks open and releases egg/ova from for fertilization
Follicle
108
No. Of dominant follicle
Only 1
109
3 phases:
follicular, fertilization/ovulation, luteal phase
110
FSH phase
follicular
111
Growth and devt of testicles
FSH
112
Sertoli cells
glycoprotein produced by SC that binds w/ testosterone
113
Epididymis and Seminiferous tubules
Testis
114
inside testis; coiled tubules
Seminiferous tubules:
115
: synthesis of sperm
Seminiferous tubules Walls
116
functions to support and nourish immature sperm
Sertoli cells
117
gives blood prods for maturation
Sertoli cells
118
aids in release from the testis
Sertoli cells
119
ACTH Stimulant:
Stress
120
Sends signal to hypothalamus to secrete CRH to stimulate the anterior pituitary gland to secrete
POMC and ACTH
121
ACTH Target organ:
adrenal gland
122
: above the kidney; secretes cortisol
adrenal gland
123
(stress hormone)
cortisol
124
Neurosecretory cells of hypothalamus secrete this in response to uterine distension and stimulation of nipples.
Oxytocin (OT)
125
Stimulates contraction of smooth muscle cells of uterus during childbirth
Oxytocin (OT)
126
stimulates contraction of myoepithelial cells in mammary glands to cause milk ejection
Oxytocin (OT)
127
OT TARGET TISSUES
Uterus, Mammary glands
128
ADH TARGET TISSUES
Kidneys, Arterioles, Sudoriferous (sweat) glands
129
Neurosecretory cells of hypothalamus secrete this in response to elevated blood osmotic pressure, dehydration, loss of blood volume, pain, or stress
Antidiuretic hormone (ADH) or vasopressin
130
inhibitors of ADH secretion includex
low blood osmotic pressure, high blood volume, and alcohol
131
Conserves body water by decreasing urine volume
Antidiuretic hormone (ADH) or vasopressin
132
decreases water loss through perspiration
Antidiuretic hormone (ADH) or vasopressin
133
raises blood pressure by constricting arterioles
Antidiuretic hormone (ADH) or vasopressin
