Endocrinology Flashcards
1
Q
How is the endocrine system related to the nervous system?
A
glands are effectors that are stimulated by motor impulses from the autonomic nervous system
2
Q
Distinguish between an endocrine gland vs. an exocrine gland
A
endocrine secretes directly into blood stream; ductless
exocrine secrete into ducts; not part of endocrine system
3
Q
What is a hormone?
A
very powerful substance secreted by an endocrine gland into the bloodstream that affects the function of another cell i.e. target cell at a distant site
4
Q
Which is the “master” endocrine gland?
A
hypothalamus
5
Q
How does the posterior pituitary gland secrete hormones, but not produce them?
A
hormones are produced by the hypothalamus and stored in the posterior pituitary
6
Q
What are the 5 characteristics of hormones?
A
- potent
- long-lasting effects on target cells
- regulate metabolic processes
- regulated by negative and positive feedback
- may be steroid or non-steriod
7
Q
What is a steriod hormone?
A
fat-soluble; passes easily through the target cell membrane
8
Q
What is a non-steriod hormone?
A
water-soluble; requires receptor on target cell membrane to allow the hormone to enter the cell; activates a second messenger inside cell
9
Q
What is the function of the endocrine system?
A
integrate body systems, maintain homeostasis, in conjuction with the nervous system
10
Q
What are the 10 glands of the endocrine system?
A
- hypothalamus
- pituitary
- pineal
- thyroid
- parathyroid
- thymus
- adrenal
- pancreas
- testes
- ovaries
11
Q
Define paracrine.
A
localized hormones that diffuse a short distance to target cells
12
Q
Define autocrine.
A
hormones that act on the cell that produced them
13
Q
Define endocrine.
A
hormones secreted directly into blood and acts at long distances
14
Q
What are the ‘‘releasing and inhibitory” hormones secreted by the hypothalamus that target the pituitary gland?
A
GH-RH&IH
TRH
CRH
PRF&PIH
GnRH
MSH-IH
15
Q
CRH
A
corticotropin-releasing hormone; targets ACTH
16
Q
GH-IH
A
growth hormone-inhibiting hormone; targets HGH
17
Q
GH-RH
A
growth hormone-releasing hormone; targets HGH
18
Q
GnRH
A
gonadotropin-releasing hormone; targets FSH & LH
19
Q
MSH-IH
A
melanocyte-stimulating hormone-inhibiting hormone; targets MSH
20
Q
PIH
A
prolactin-inhibiting hormone; targets PRL
21
Q
PRF
A
prolactin-releasing factor; targets PRL
22
Q
TRH
A
thyrotropin-releasing hormone; targets TSH
23
Q
HGH
A
human growth hormone
controls growth of the body; targest bone, muscle and adipose tissue
from pituitary, called
somatotropin –> liver –>somatomedin
which is directly responsible for muscle and bone
24
Q
What are the other terms for the anterior pituitary gland?
A
adenohypophysis
pars distalis (embryonic)
25
TSH
thyroid stimulating hormone
controls secretion of hormones by thyroid
26
ACTH
adrenocorticotropic hormone
controls the secretion of hormones (cortisol) by the adrenal cortex
targets outer portion of the adrenal cortex
27
PRL
prolactin
stimulates production of milk by mammary glands
inhibitory effect on FSH
28
FSH
follicle stimulating hormone
in females, stimulates maturation of ovarian follicle and ovum; formation of endometrium in uterus
in males, stimulates maturation of sperm in testes
gonadotropin, targets primary sex organs
29
LH
luteinizing hormone
in females, causes ovulation
in males, causes secretion of testosterone; aka ICSH (interstitial cell stimulating hormone / Leydig)
gonadotropin
30
MSH
melanocyte stimulating hormone
unknown significance
melanin production
31
What are the other terms for the posterior pituitary gland?
neurohypophysis
pars nervosa (embryonic)
32
anterior pituitary gland
base of the brain, sits in sella turcica, secretes 7 different hormones
33
What are the 7 hormones secreted by the anterior pituitary gland?
HGH
TSH
ACTH
PRL
FSH
LH
MSH
34
posterior pituitary gland
located behind anterior pituitary gland
continuous with nerve fibers of the supraopticohypophyseal tract of the hypothalamus
does not produce hormones; only stores them
35
What 2 hormones are produced by the hypothalamus and stored in the posterior pituitary?
ADH
OT
36
ADH
anti-diuretic hormone
targets collecting ducts of kidneys
made in supraoptic nuclei of hypothalamus
causes reabsorption of water back into bloodstream (increases blood pressure)
37
OT
oxytocin
targets uterine smooth msucle and breasts
produced in paraventricular nuclei of hypothalamus
causes labor contractions and milk secretion
38
Label the diagram
1. pineal
2. hypothalamus
3. pituitary
4. thyroid
5. parathyroid
6. thymus
7. adrenals
8. pancreas
9. ovaries
10. testes
39
thyroid gland
Location: below larynx around trachea
Function: regulates basal metabolic rate, lower blood calcium levels
Produces: triiodothyronine, tetraiodothyronine
Requires: iodine, tyrosine
40
T4 & T3
T4-T3 ratio of 9:1
T4 is the storage form
T3 is the biologically active form
deiodinase (enzyme) converts T4--\>T3
Functions: increase basal metabolic rate by stimulating cellular oxygen use to produce ATP; regulate metabolism
41
calcitonin
secreted by C cells (parafollicular)
decreases blood calcium to normal range (8.5-11 mg/dl)
42
parathyroid
4 small glands located within thyroid
chief cell is the parenchymal cell; produces PTH; increases blood calcium levels
increase absorption in small intestine, reabsorption in kidney w/vitamin D; resorption from bone
43
adrenal glands
aka suprarenals
located on top of kidneys; divided into inner renal medulla and outer adrenal cortex
44
adrenal medulla
central portion
produces catacholamines (norepinephrine, epinephrine) which function in the sympathetic nervous system
targets:
heart (SA node to increase HR)
smooth muscle
* peripheral arterioles (vasoconstriction, increase BP)
* terminal bronchioles (bronchodilation, increase depth of breathing
diaphram (increase breathing rate)
45
epinephrine
tyrosine --\> L-DOPA --\> dopamine --\> norepinephrine
--\>add methyl group (CH3) --\> epinephrine
46
seratonin
tryptophan --\> 5-hydroxytryptophan --\> 5H tryptamine
aka seratonin
47
adrenal cortex
outer portion of adrenals
stimulated by ACTH
mineralcorticoid
glucocorticoid
supplemental sex hormones (estrogens, adrogens)
48
zona glomerulosa
outer most area of adrenal cortex
produces mineralcorticoid: aldosterone targets distal convoluted tubules, reabsorption of water/electrolytes
49
zona fasciculata
middle layer of adrenal cortex
glucocorticoid: cortisol targets all cells, regulates glucose metabolism (along with T3and T4)
50
zona reticularis
inner layer of adrenal cortex
supplemental sex hormones (estrogens, adrogens)
51
pancreas
behind stomach, left side
functions as mixed gland
52
islets of Langerhans
endocrine organs within pancrease
produce insulin & glucagon
53
insulin
produced by beta cells
secretion stimulaed by increase BS levels
decreases BS levels (moves glucose from blood into cells and promotes gycogen formation in liver and skeletal muscle)
54
glucagon
produced by alpha cells
secretion stimulated by decreased BS levels
increases BS levels (breakdown of glycogen and release into blood)
55
thymus gland
located in mediastinum region behind sternum
produces thymosin that affects the maturation of lymphocytes (T-cells)
plays an important role in lymphatic system and immunity
decreases in size with age
56
pineal gland
attached to the thalamus of the brainstem
secreates melatonin; stimulated by light, affects moods, emotions, etc.
57
ovaries
FSH: maturation of ovarian follicle and ovum
estrogen: from follicle; female secondary sex characteristics; targets hair follicles in axillary/inguinal regions, mammary glands/breasts, adipose tissue in hips, thights, buttocks
LH: ovulation
progesterone: from corpus luteum (post ovulation); prepares uterine lining fro implantation of zygote
58
testes
FSH: production of sperm
LH: production of testosterone
testosterone: male secondary sex characteristics; targets hair follicles in axillary/inguinal regions, muscle/bone, vocal cords in larynx
59
GH imbalances
pituitary dwarfism
pituitary giantism
acromegaly
60
pituitary dwarfism
hyposecretion of GH during childhood
slow bone growth and early closure of epiphyseal plates (usually reach 42-48")
treatment: oral GH therapy
61
pituitary giantism
hypersecreation of GH during childhood
abnormal increas in length of long bones; usually causes cardiomegaly
62
acromegaly
hypersecretion of GH during adulthood
bones of hands, feet, cheeks and jaw thicken (long bones get wider, flat bones get thicker)
soft tissues also grow
63
ADH imbalances
diabetes insipidus
SIADH
64
diabetes insipidus
hyposecretion of ADH
diuresis (polyurea), dehydration, thirst (polydipsia)
65
SIADH
syndrome of inappropriate ADH
usually caused by certain cancers
66
thyroid imbalances
cretinism
myxedema
hashimotos
graves
goiter
67
cretinism
hyposecretion of T3/T4 during infancy
lack of iodine
dwarfism, mental retardation
treatment: oral thyroid therapy
68
myxedema
hyposecretion in adulthood; water retention in legs
swollen face, decreased metabolic rate, psychomotor sluggishness, somnolence, bradycardia, reduced catecholamine sensitivity, decreased appetite, constipation, decreased perspiration, dry skin/hair, decreased muscle tone, reflexes, hypoventilation, increased serum cholesterol, cold intolerance, weight gain
TRH/TSH elevated, T3/T3 low
69
Hashimoto's
autoimmune hypothyroid
70
Grave's
autoimmune, growth of thyroid, hypersecretion, no negative feedback; T3/T4 elevated, TSH/TRH low
exophthalmos, lid lag, impaired blinking, increased metabolic rate, restlessness, irritibility, anxiety, hyperactivity, sleeplessness, tachycardia, heightened catecholamine sensitivity, increased appetite, diarrhea, increased perspiration, silky hair, increased muscle tone, reflexes, tremors, dyspnea, decreased serum cholesterol, heat intolerance, weight loss
surgical removal and/or radioisotopes
71
goiter
hypertrophy and hyperplasia
toxic - Grave's
nontoxic - Hashimoto's
72
parathyroid hormone imbalances
primary (osteitis fibrosa cystica)
secondary (osteodystrophy)
73
primary hyperparathyroidism
functional tumor with excess PTH
blood calcium elevated
remove tumor
74
secondary hyperparathyroidism
chronic renal failure
decreased vitamin D, blood calcium, elevated PTH
75
diabetes mellitus
symptoms: polyuria, polydipsia, polyphagia
hyperglycemia
complications: CV disease, gangrene, blindness, renal failure
types: type I, type II, gestational
76
type I diabetes
autoimmune, destroys beta cells, insulin dependent
generally presents younger than age 20
fat broken down, releasing ketone bodies resulting in ketoacidocis (pH less than 7.35)
treatment: artificial pancreas, transplant (pancreas, beta cells)
77
ketone bodies
ß-hydroxy-butyric acid
acetoacetic acid
acetone
78
type II diabetes (90%)
insulin independent; insulin receptors down-regulate
patients \>40y; obesity, hypertension, controlled by diet, physical activity, weight loss, sleep
treatment: medications
79
gestational diabetes
prediabetic adult
testing at 18wks
80
adrenal corticol hormone imbalances
Addison's
Cushing's
81
Addison's
hyposecretion of hormones due to autoimmunity or disease (TB); CRH & ACTH increased, cortisol decreased
mental lethargy, anorexia, nausea/vomiting, weight loss, hypoglycemia, muscle weakness, increased potassium, decreased sodium, low BP, dehydration, arrhythmias, cardiac arrest, increased skin pigmentation
82
The two hormones that work together to regulate water, electrolyte levels, and blood pressure are
ADH
aldosterone
83
Why does the thymus gland decrease in size as we age?
immune system produces most of its T cells during childhood
84
Which gland (and its hormone) is stimulated by sunlight?
pineal (melatonin)
85
