Module 1: Endocrine Flashcards
1
Q
The endocrine system works
A
In the background to maintain homeostasis and regulate functions if all systems
2
Q
Hormones are background
A
Are background controllers of all activities in the body, sort of like invisible strings resulting in widespread physiological events
3
Q
Hormones are
A
Chemicals produced by the body that have a specific regulatory effect on the target cell or organ
4
Q
7 classic endocrine glands
A
Pituitary gland, adrenal gland, thyroid gland, parathyroid gland, pancreas, ovary, testies
5
Q
Other organs that secrete hormones
A
Hypothalamus, heart, kidneys, gastrointestinal tract, liver, adipose tissues, and bones
6
Q
Endocrine disease
A
Excess or deficiency of a hormone, OR defect in hormone receptors or intercellular signaling
7
Q
Hormone secretion area: hypothalamus
A
THR, CRH, GHRH, Dopamine, Somatostatin, and Vasopressin
8
Q
Hormones secretion area : thyroid and parathyroid
A
T3, T4, calcitonin, PTH
9
Q
Hormone secretion area: liver
A
IGF, THPO
10
Q
Hormone secretion area: adrenal
A
Androgen, glucocorticoids, adrenaline, noradrenaline
11
Q
Hormone secretion area: kidney
A
Calcitriol, Renin, Erythropoietin
12
Q
Hormone secretion area: testes
A
Androgen, estradiol, inhibin
13
Q
Hormone secretion area: pineal gland
A
Melatonin
14
Q
Hormone secretion area: pituitary gland
A
GH, TSH, ACTH, FSH, MSH, LH, prolactin, oxytocin, vasopressin
15
Q
Hormone secretion area: thymus
A
Thymopoietin
16
Q
Hormone secretion area: stomach
A
Gastrin, Ghrelin, Histamine, Somatostatin, Neuropeptide Y
17
Q
Hormone secretion area: pancreas
A
Insulin, glucagon, somatostatin
18
Q
Hormone secretion area: ovary
A
Placenta, estrogen, progesterone
19
Q
Hormone secretion area: uterus
A
Prolactin, relaxin
20
Q
3 types of hormone signaling
A
- Endocrine
- Paracrine
- Autocrine
21
Q
Endocrine signaling
A
Hormone is carried a distance by blood (produce by the endocrine organs)
22
Q
Paracrine signaling
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Hormones diffuses in local extra cellular fluid act in neighboring cells of a different cell type
23
Q
Autocrine signaling
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Hormone secreted act on cell itself, or other cells of the same type (local)
24
Q
4 classes of hormones
A
- Peptides
- Steroids
- Amines
- Small molecules
25
Peptides
Comprised of amino acids (smaller than protein), hydrophilic (water soluble) = dissolved in water and move through blood easily no need for carrier, location = plasma membrane, MOA = main,y secondary messengers, speed= usually fast onset but short acting response, not stored in vesicles prior to secretion
E.g., pancreatic, pituitary, parathyroid, GI hormones
26
Steroids
Cholesterol based - hydrophobic, need a carrier, not stored in vesicles prior to secretion, location= intracellular, MOA= mainly altered gene expression, speed = usually slow onset but long lasting responses
E.g., sex hormones, cortisol, aldosterone, VitD
27
Amines
Tyrosine based, variable hydrophilicity
E.g., catecholamines- more like peptides (dopamine, EPI, NE): thyroid hormones - more like steroids
28
Small molecules
Gases, ions, amino acids based, varies in hydrophilicity
E.g., serotonin, nitric oxide, adenosine, Ca2+
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Hormone response =
Magnitude of response depends on the number of receptors on a cell that are occupied by the hormones
Depends on free hormone concentration
Affected by: secretion, elimination, and extent of binding o plasma proteins
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Rate of hormone
Usually under negative feedback control
Simple negative feedback: a hormone inhibits it’s own further secretion
Complex/ hierarchical: hormones secreted from the target organ inhibits releasing hormones secreted from upstream (hypothalamus or pituitary)
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Endocrine disorders; primary
target gland - e.g., T3 or T4 from thyroid itself
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Endocrine disorders: secondary
Pituitary gland -e.g., TSH
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Endocrine disorders: tertiary
Hypothalamus- TRH
34
Endocrine disorders (3)
Primary
Secondary
Tertiary
35
Positive feedback
A hormone result in more than it’s own release (result in ‘event’)
Childbirth
36
Feed forward control
Anticipatory release of hormone
E.g., glucose in the stomach —> triggers insulin to be released before glucose enters the blood (which will then regulate the blood glucose levels)
37
4 types of hormones receptors at the target cell
Ligand gated ion channels (ionotropic)
Catalytic receptors
G-protein coupled receptors
Intracellular receptors
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Ligand gated ion channel (ionotropic)
Hormone/ ions binds to receptor and open channel (e.g., Ca2+)
Receptors outside the channel and control the opening and closing of the channel —> change in voltage in membrane
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Catalytic receptors
Hormones binds and stimulates enzymes activity inside the cell (e.g., kinases)
From the outside to inside the membrane
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G-protein coupled receptors
Hormone binds the receptor, which has a G-complex inside the cell, which stimulated to perform its action
Site outside to receive hormone
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Intracellular receptors
The hormone enters the cell and binds a receptor, which stimulates gene transcription (e.g., steroids, VitD)
Diffuse through the cell membrane on inside = gene transcription
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Cell response to hormones: only occurs in cell with a receptor
Altered membrane voltage of the target cell
Gene transcription within the target cell
Phosphorylation or dephosphorlation of target protein within the target cell often effects second messengers
43
2nd messengers
Connect the receptor-binging to changes in cell function activity (changes effect on inside and can amplify)
Amplify hormone signal
Integrate simultaneous hormone signals coming in
44
G-proteins
Hormone binds G-protein coupled receptors
G-alpha subunit
* exchanges GDP for GTP and dissociates from beta-gamma
* regulates downstream effector proteins
* hydrolysis ATP to stop signal
45
Hypothalamus made of a
cluster of neurons (nuclei) located within the brain, connected to the pituitary by a stalk
46
The pituitary has 2 lobes
Anterior pituitary
Posterior pituitary
47
Anterior pituitary made of
Grandular tissue (separate gland)
48
Posterior pituitary made of
Non-myelinated nerve axons and nerve terminals that extends from the hypothalamus (almost an extension)
49
Posterior Pituitary (Neurohypophysis - nerves from hypothalamus)
Hormones are produced by the neurons in the hypothalamus, which then travels down their axons to be secreted by the posterior pituitary into circulation
Antidiuretic hormone (ADH), Vasopressin
Oxytocin
50
Antidiuretic Hormone (ADH) or Vasopressin
Main hormone that control water balance in the body (to retain water)
51
ADH or Vasopressin is secreted in response to
increased extracellular fluid osmolarity (dehydration)
decrease blood volume (hypovolemia)
52
ADH or Vasopressin response to dehydration
vasoconstriction (smooth muscle cells)
increased eater reabsorption in kidneys (increased urine concentration)
stimulates thirst to restore hydration
53
Oxytocin
release through posterior pituitary
stimulates uterine concentrations for childbirth, and after birth to prevent postpartum hemorrhage
stimulates milk let down and ejection with lactation
promotes maternal and social bonding behavior's
stimulates smooth muscle contraction for ejaculation with sexual function
54
Anterior pituitary (adenohypophysis)
connected to hypothalamus by hypophyseal blood flow (group of blood vessel)
hypothalamus sends "releasing hormones" to the anterior pituitary by this vascular connection, which stimulates anterior pituitary to secrete its hormones
5 "tropin" hormones, which will target another organ to release another hormone
1 non-tropin hormone (prolactin)
55
Prolactin
Non-tropic hormone from the anterior pituitary
produce by lactotropes
release is stimulated by infant suckling and coordinates with oxytocin for nursing
anterior (release prolactin) --> hypothalamus --> posterior (release oxytocin)
normally low in not pregnant females and in men
56
Growth Hormone Axis
released is stimulates by hunger, hypoglycemia (low blood sugar), protein ingestion
stimulates:
- growth in child by stimulating insulin - like growth factor (IGF-1) secretion
- lean body mass maintenance in adults
- anti-insulin effects
57
2 hormones produced by the hypothalamus and secreted from the posterior pituitary
Oxytocin and Antidiuretic hormone
58
5 tropin hormones
1. Thyroid stimulating hormone (TSH)
2. Andrenocorticotropic hormone (ACTH)
3. Luteinizing hormone (LH)
4. Follicle Stimulating hormone (FSH)
5. Growth Hormone (GH)
59
Thyroid Stimulating hormone (TSH)
Comes from Thyrotropin releasing hormone (TRH) - from hypothalamus
Targets cells in AP - thyrotropes
result in secretion of T3 and T4
60
Adrenocorticotropic Hormone (ACTH)
Comes from Corticotropin releasing hormone (CRH) - from hypothalamus
Targets cells in AP - corticotropes
result secretion of adrenal gland (cortisol)
61
Luteinizing hormone (LH)
1Comes from Gonadotropin releasing hormones (GnRH)- from the hypothalamus
Targets cells in AP = Gonadotropes
result secretion of ovaries (estrogen, progesterone) and testes (testosterone)
62
Follicle stimulating hormone (FSH)
2Comes fromGonadotropin releasing hormones (GnRH)- from the hypothalamus
Targets cells in AP = Gonadotropes
result secretion of ovaries (estrogen, progesterone) and testes (testosterone)
63
Growth Hormone (GH)
Comes from Growth Hormone releasing hormone (GHRH) - from the hypothalamus
Target cells in Ap= Somatotropes
results in numerous organ and cells
64
thyroid (location)
anterior to trachea (normally not palpable but maybe when pregnant or have a certain disorder)
right and left side connected by central isthmus
65
Thyroid hormone production by follicular cells
multiple steps for synthesis, secretion, activation, and inactivation of thyroid hormones
can be involved in primary disorders of the thyroid (either hyper/ hypo active)
T3 and T4
66
T3
Triiodothyronine (10%)
3 iodination sites filled
biologically active form
67
T4
thyroxine (90%)
4 iodination site filled
prohormone for T3
68
Thyroid hormone action
Act primarily via nuclear receptors (inside the cell)
increased basal metabolic rate (increased heat)
increase Na-K-ATPase activity
increases beta-adrenergic receptors
69
Primary Hypothyroidism
Most common type of hypo
problem with the thyroid gland itself - not enough T3/T4
result: Lack of negative feedback to anterior pituitary and hypothalamus
High levels of TSH (attempts upstream to stimulate T3/T4 production)
TSH causes growth of thyroid - goiter can form
Low T3/T4, High TSH and TRH (can be seen in serum test)
70
secondary hypothyroidism
Rare
problem with anterior pituitary - not enough SH
result: lack of stimulus to thyroid - low T3/T4 produced
serum test: low T3/T4, low TSH, High TRH
71
Primary Hyperthyroidism
thyroid gland produces to much hormone despite lack of stimulus upstream
result: because T3/T4 are high, they give strong feedback to the pituitary and hypothalamus - thus, TRH and TSH are low
Serum test: High T3/T4, Low TSH and TRH
72
Secondary Hyperthyroidism
Anterior pituitary gland produce to much TSH
Result: despite lack of stimulation from the hypothalamus and negative feedback from thyroid hormones
high levels of T3/T4 results
Serum test: High TSH and T3/T4 ( low TRH)
73
Adrenal (suprarenal) glands (location)
Bilateral, above each kidney
each one is composed of outer cortex and inner medulla
74
Adrenal gland layers and zones
Layers:
Capsule, medulla,
Zones:
Glomerulosa, fasciculata, reticularis
75
Cortisol release
steroid (cholesterol-based hormone
response to:
-stress (trauma, infection, illness, temperature change, mental stress)
-circadian rhythm- levels higher in morning (awake, alert)
absence of cortisol is fatal
mobilizes glucose and fatty acids: flight or flight
vasoconstriction - increase blood pressure
anti-inflammatory immune functions
suppresses the immune system
76
Aldosterone
Steroid (cholesterol-based hormone)
response to the renin-angiotensin system (the "RAS") and to increased plasma potassuim (K+) concentration
Absence of aldosterone is fatal
Ultimately, results in water retention
- conserves sodium (Na+) in extracellular fluid
-promotes potassium (k+) excretion in kidneys
also affects distal colon, sweat glands, and salivary glands
77
Renon-angiotensin system (background)
trigger: low blood volume (dehydration, blood pressure dropping)
how does the body know that blood volume is low?
- decrease renal perfusion, glomerular filtration
- there is also stimulation of renal sympathetic nerves (beta -1 adrenergic receptors) on the juxtaglomerular) apparatus in the kidneys
these factors will stimulates release of renin
78
Renin-Angiotensin system (how)
renal juxtaglomerular (JG) apparatus release renin (on enzyme) --> renin cleaves circulating angiotensinogen --> converts it to angiotensin 1
angiotensin- converting enzyme (ACE) (found on vascular endothelial cells, ~ 50% activity in the lungs) cleaves angiotensin 1 and converts it to angiotensin 2
angiotensin 2 binds receptors in the adrenal cortex glomerulosa, stimulating aldosterone secretion
79
Epinephrine/ Norepinephrine
Are catecholamines --> triggers: stress sympathetic stimulation
cortisol triggers the conversion of dopamine to form epinephrine and norepinephrine
effects: depends on the adrengeric receptor that is present on the cell/tissue/ organ
alpha-1, alpha-2, Beta-1, Beta-2 and Beta-3 receptors
80
short term stress response
catecholamines (EPI, NE)
increases cardiac output, bronchodilation, elevated blood glucose
81
long term stress response
cortisol
mobilization of glucose, fatty acid, amino acids
immune system suppression
82
Endocrine cell in the Pancreas
Forms islets of langerhans
Alpha-cells on the periphery, secrete glucagon
beta-cells- in the center; secrete insulin, C-peptide, and amylin
delta-cells - scattered, secrete somatostatin
blood flows from center outwards
brings insulin (from beta-cells) to the outer alpha cells, which suppresses them from secreting glucagon
83
alpha cells
on the periphery; secrete glucagon
84
beta cells
in the cell center; secrete insulin, c-peptides, and amylin
85
delta cells
scattered; secrete somatostatin
86
Hormones of the endocrine pancreas
Insulin, Glucagon, Amylin, Somatostatin
87
insulin (beta-cells)
moves circulating glucose, amino acids, fatty acids, and ketocids into storage- anabolic function (builds things) - important for normal childhood growth
- storage occurs in the liver, adipose tissue, skeletal muscle
=secretion is stimulated by blood glucose, amino acid, ketoacids
-inhibited by stress, exercise, hypoglycaemia
88
Glucagon (alpha cells)
-antagonist to insulin - mobiles glucose to the blood
-glucose production in the liver
- lipolysis in adipose tissue
-glucagon secretion is stimulated by hypoglycemia
-secretion is inhibited by insulin and hyperglycemia
89
Amylin
stored with insulin in beta cells, decrease spike in blood glucose by:
-slows gastric emptying
-increase satiety
-inhibits glucagon secretion
-can accumulate and injury beta-cells in type 2 diabetes
90
Diabetes
-hyperglycemia due to lack of or insensitivity to insulin
-causes systemic damage over time ('silent killer')
-leading cause of blindness, non-traumatic LE amputation, and end-storage renal disease
-symptoms: polyuria, Polynesia, unintentional weight loss
-normal fasting blood glucose concentration: 70-90 mg/dL
-normal glycated hemoglobin AIC (glycemic control over prenious months): 4.0-5.6%
91
normal fasting blood glucose cencentration
7-90 mg/dL
92
Normal glycated hemoglobin AIC
4.0-5.6%
93
Type I diabetes
-lack of insulin
-5% of all cases
-usually due to autoimmune attack on bata cells, resulting in lack of insulin production
-insulin-dependent diabetes
-lack of insulin results in unopposed glucagon activity--> ketoacidosis
94
Type 2 diabetes
-insulin insensitivity
-obesity-related, particularly visceral obesity
-adipose tissue produces inflammatory cytokines that cause resistance to insulin at target cells that would normally uptake glucose
-initial response: increase insulin production (compensatory hyperinsulinemia)
-overtime, beta cells are lost --> insulin dependent
-often associated with "metabolic syndrome"
95
Parathyroid hormone (PH) and VitD regulates
Calcium (Ca2+) and phosphate balance --> they form the hydroxyapatite crystals in bone
homeostasis in plasma levels
Balance must occur between:
-input: absorbed in the intestine, resorption of bone
-output: exerted urine, bone formation
96
adolescent bone formation
Most bone mass is accumulated in childhood and adolescence
- weight-bearing activities and proper nutrition
97
peak bone mass occurs by
age 18 - girls
age 20 - boys
98
Parathyroid hormone (PTH)
-secreted by the parathyroid gland
-release stimulated primarily by a drop in blood plasma Ca2+
- effects on osteoclasts/ blasts, kidneys, and on VitD synthesis:
* increase plasma Ca2+
* decreases plasma phosphate
99
Vitamine D
-Skin with sun exposure; dietary intake
-activated in the kidneys
promotes absorption (small intestine) of Ca2+ and phosphate
100
Calcitonin
-Secreated by the thyroid
-opposes PTH: reduces plasma Ca2+
* decrease bone absorption
* increase urinary Ca2+ excretion
101
Hormones can be carried in the bloodstream to distant target organs, which is termed as ____ signaling
Endocrine
102
Hormones can also be released locally into extracellular fluid and then act on local cells, without traveling in the bloodstream, as occurs with ____ signaling.
Autocrine and paracrine
103
Which of the following class of hormones always needs a carrier protein due to its hydrophobic properties?
A. peptids
B. steroids
C. amines
D. small molecules
B.steroids
104
The ____ are unique in that they are cholesterol-based and this always hydrophobic, requiring a carrier protein to take them into the cell to perform transcription
Intracellular receptors
105
while hormones attached to a receptor on the outside of the cell, the alpha-unit of G-protein ___ are located on the inside of the cell and perform the effector actions signaled by the hormones
Coupled receptors
106
___ also binds hormones on the outer surface of the cell, which then results in an enzyme reaction occurring inside the cell
Catalytic receptors
107
The unique features of ___ is that they result in a channel opening that spans the cell membrane, which can result in activities such as cell membrane Voltage changes
Ligand-gated ion channel
108
Gland that sits anterior to the trachea
Thyroid
109
a condition in which there is too much thyroid hormone activity
hyperthyroidism
110
or T4, the prohormone for T3
Thyroxine
111
a condition in which there is not adequate thyroid hormone activity
hypothyroidism
112
or T3, the biologically active form of thyroid hormone
triiodothyronine
113
indicates there is a problem with the thyroid itself (hypo- or hyper- thyroidism)
Primary
114
the tissue that connects the right and left halves of they thyroid together
Isthmus
115
the cells that produce thyroid hormones
Follicular
116
which is the more biologically active form of thyroid hormone
T3 (triiodothyronine)
117
what are hormones?
Chemicals produced by the body that have a specific regulatory effect on a target cell or organ
118
what is the difference between "endocrine" and "paracrine/autocrine" signaling?
endocrine-bloodstream
paracrine/autocrine- local/nearby cells
119
what is the most common type of hormone secretion regulation?
Negative feedback - secretion of a hormone inhibits its own further secretion or of releasing/ tropin hormones upstream
120
what would you expect of TSH and T3/T4 levels with primary hyperthyroidism
High T3/T4
Low TSH
121
If Ca2+ (acting as a hormone) attaches to a receptor that causes a channel to open, that kind of receptor is this?
Ligand-gated ion channels (or ionotropic) receptors
122
what is known as the "adenohypophysis" and why
Anterior pituitary - because it made of grandular cells/tissues, and produce/secretes its own hormones
123
what are the 2 hormones that are essential for life, and what gland produces them?
cortisol and aldosterone- from the adrenal glands (or suprarenal glands)
124
what cells are damaged in the pancreas due to chronic type 2 diabetes?
beta cells
125
How do parathyroid hormone (PTH) and calcitonin differ?
Parathyroid hormone- causes bone breakdown (increase Ca2+ in the blood)
Calcitonin- inhibits bone breakdown
