Endocrine System Part 1 Flashcards
Learn the Endocrine System
1
Q
Endocrinology
A
Study of hormones and endocrine organs
2
Q
the Endocrine System acts with the __________ __________ to coordinate and integrate activity of body cells
A
nervous system
3
Q
how does the endocrine system influence cellular acitivies?
A
via hormones transported in blood
4
Q
Responses are _________ but also __________ lasting than the nervous system response
A
slower but also longer lasting
5
Q
Endocrine glands
A
produce hormones, secrete into the blood stream but lack ducts
6
Q
Exocrine glands
A
- produce non-hormonal substances (sweat, saliva, digestive enzymes) but have ducts to carry secretion to the membrane’s surface
7
Q
What are examples of endocrine glands?
A
pituitary, thyroid, parathyroid, adrenal, and pineal glands
8
Q
What kind of gland is the hypothalamus classified as?
A
a nueroendocrine organ
9
Q
There are 6 other organs and tissues that produce hormones. Please list them.
A
Adipose cells
Thymus
cells in walls of small intestine
stomach
kidneys
heart
10
Q
Endocrine tissues are….
A
diverse and decentralized (many types at many locations)
11
Q
Hormones
A
long-distance chemical signals; travel in blood or lymph
12
Q
autocrines
A
chemicals that exert effects on same cells that secrete them
13
Q
paracrine
A
locally acting chemicals that affect cells other than those that secrete them
14
Q
Autocrines and Paracrines are _______ _________ _______ and not considered part of the endocrine system
A
local chemical messengers
15
Q
Endocrine Cells
A
releases hormones into the blood stream
- only cells with receptors for that particular hormone will respond
16
Q
study the different kinds of signaling slide (12 on lecture 1)
A
…
17
Q
Properties of hormones
A
- regulation of physiological processes
- variety in chemical structure
- released in very low quantities
- movement through plasma
- bind to receptors on or in target cells
- released in response to changes to maintain homeostasis
18
Q
what are the 3 chemical families?
A
Amines, Peptides and proteins, and steroids
19
Q
Amines
A
are derived from animo acids tyrosine or tryptophan (epinephrine, thyroid hormones)
20
Q
Peptides and protiens
A
chains of amino acids (insulin, ADH)
21
Q
Steroids
A
derived from cholesterol and are lipid soluble (testosterone, cortisol)
22
Q
Synthesis of amino acied derivative hormone
A
biochemically synthesized from amino acids and stored within vesicles (epinephrine)
23
Q
Peptide and protein hormones are synthesized in an _______ ________
A
inactive form
24
Q
Peptide and protein synthesis is…
A
encoded in genes- multiple peptide hormones can be encoded by one gene
25
Signal Peptide
directs hormone to correct intracellular organelle for processing
26
Steroid hormones synthesis
biochemically synthesized from cholesterol (cortisol, estrogen, androgens)
27
What are the water soluble hormones
all the amino acid-based hormones except for the thyroid hormone
28
water soluble hormone properties
cannot enter the cell
act on plasma membrane receptors
Act via G protein coupled receptors and second messengers
29
What are all of the lipid-soluble hormones?
steroid and thyroid hormones
30
What are properties of lipid-soluble hormones?
- can enter the cell
- act on intracellular receptors that directly activate genes
- carried in plasma by plasma proteins
31
How are fat-soluble hormones transported through the blood?
99% are bound to a transport protein while 1% is free floating
32
How are water-soluble hormones transported?
100% free floating in the blood
33
Hormones are excreted in the ______ or ________ tract
urine, digestive
34
How are water-soluble, free hormones excreted?
they are smaller than the kidney filtration barrier, so they are excreted in the urine
35
How are lipid-soluble hormones excreted?
- some excreted in urine (if chemically modified to be more water-soluble)
- otherwise excreted in GI tract
36
Half life (T1/2)
time required to reduce blood concentration by 50%
37
Increases t 1/2
increased synthesis
increased secretion
binding to transport proteins
modification of structure
38
decreases t 1/2
decreased synthesis
decreased secretion
excretion by kidney or bile
enzymatic degradation
39
Hormone release is _______ - __________
amplitude- modulated
40
neurotransmitter
- release is "all or nothing"
- levels vary with frequency
41
How do hormones release?
- levels never approach zero
- fluctuate between high and low
- controlled by negative feedback systems
- increased hormone effects on target organs can inhibit further hormone release
42
Processes that influence hormone secretion
- changes in critical physiological factor (ions)
- direct input from the nervous system through neurohormone release
- actions of other hormones (hypothalamic regulation of pituitary gland)
- Mechanical stresses or cellular metabolism
43
Endocrine glands are stimulated to synthesize and release hormones in response to these three stimuli:
- humoral stimuli
- neural stimuli
- hormonal stimuli
44
Humoral stimuli
- changing blood levels of ions and nutries direction stimulation secretion of hormones
45
What is an example of humoral stimuli?
- Ca 2+ in the blood
- when calcium declines, stimulations parathyroid to secrete PTH (parathyroid hormone)
- PTH causes calcium conc to rise and stimulus is removed
46
Neural Stimuli
- Nerve fibers stimulate hormone release
- sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines (epinephrine, norepinephrine)
47
Hormonal Stimuli
Hormones stimulate other endocrine organs to release their hormones (tropic effect)
48
Hormonal Stimuli steps
1. Hypothalamic hormones stimulate release of most anterior pituitary hormones
2. anterior pituatary hormones stimulate targets to secrete still more hormones
3. Hypothalamic- pituitary- target endocrine organ feedback loop
49
G- Protein coupled receptors (GPCRs)
- hormone receptors
- integral membrane proteins
- extracellular region binds hormone
- intracellular region interacts with G-proteins
50
study slide 29 of lecture 1
51
one-transmembrane spanning receptors (1-TMS)
- hormone receptors
- integral membrane proteins
- extracellular region binds hormone
- intracellular region contains a kinase domain; directly phosphorylates enzymes without G-proteins
52
Nuclear Receptors
- hormone receptor
- found inside the cell
- acts as a transcription factors
- generally cytoplasmic proteins
- hormone binding leads to translocation to the nucleus
53
Target cells must have...
specific receptors to which hormone binds
54
Target cell activation depends on what 3 factors?
- blood levels of hormone
- relative number of receptors on/in target cell
- affinity (strength) of binding between receptor and hormone
55
up-regulation
target cells from more receptors in response to low hormone levels
56
down- regulation
target cells lose receptors in response to high hormone levels
- desensitizes the target cells to prevent them from overreacting to persistently high levels of hormone (Type 2 diabetes)
57
Hormones regulate the ________ ________ of other hormones
receptor levels
58
How does upregulation regulate receptor levels of other hormones?
increasing receptor levels on target cells
59
How does downregulation regulate receptor levels of other hormones?
decreasing receptor levels on target cells
60
permissiveness
the process of hormones regulating the receptor levels of other hormones
61
in rare cases a hormone can...
regulate levels of its own receptor
62
Multiple hormones may act on...
the same target at the same time
63
Permissiveness (target cell response)
one hormone cannot exert its effects without another hormone being present (reproductive hormones need thyroid hormone to have effect )
64
Synergism
more than one hormone procduces same effects on target cell, causing amplification (glucagon and epinephrine both cause liver to release glucose)
65
Antagonism
one or ore hormones opposes action of another hormone (insulin and glucagon)
66
The Hypothalamus is connected to the ____________ ___________ vial stalk called _______________
Pituitary gland, infundibulum
67
Two major lobes of the hypothalamus
posterior pituitary
anterior pituitary
68
Posterior pituitary
composed of neural tissue that secretes neurohormones
69
anterior pituitary
consists of glandular tissue
70
anatomy of the hypothalamus
- located inferior to the thalamus; part of the limbic system
- contains many distinct nuclei that produce and release unique hormones
71
Hypophyseal Portal System
connects hypothalamus and anterior pituitary via two capillary beds in series
72
Anatomy of the pituitary gland
- located inferior to the hypothalamus
- composed of anterior, intermediate, and posterior lobes
73
Anterior lobe of pituitary gland
major controller of other endocrine organs
74
Posterior lobe of pituitary gland
secretes two hormones produced by neurons in the hypothalamus
75
Study slide 41 of lecture 1
...
76
Posterior Pituitary Hormones
Oxytocin, Antiduretic hormone (ADH)
77
Oxytocin
- strong stimulant of uterine contractions released during childbirth
- triggers milk ejection (letdown) all positive feedback mechanisms)
- social behavior- contentment, reduced anxiety, calmness
78
Antidiuretic Hormone (ADH)
Hypothalamus contains osmorecptors
- concentration too high posterior pituitary is triggered to secrete ADH
- targets kidney tubulues to reabsorb more water to inhibit urine formation
- release also triggered by low blood pressure (Vasopressin)
79
Osmoreceptors
monitor solute concentrations
80
Diabetes Insipidus
- ADH deficiency due to damage to hypothalamus or posterior pituitary
81
Polyuria
large volume of dilute urine
82
Polydipsia
must keep well hydrated, very thirsty
83
Anterior Posterior Pituitary is glandular tissue derived from an outpocketin of oral mucosa. This is vascularly.....
connected to hypothalamus via hypophyseal portal system
84
Hypothalamus secretes ____________ and _______________ hormones to anterior pituitary to regulate hormone secretion (tropic effect)
releasing and inhibiting
85
study slide 47 lecture 1
...
86
Hypothalamus releases hormones that act on _________ ___________ __________
anterior pituitary gland
87
Thyrotopin-releasing hormone (TRH)
- produces on parvocellular cells in the paraventricular Nucleus
- triggers TSH and prolactin release
88
Corticotropin-releasing hormone (CRH)
- produced on parvocellular cells in the paraventricular nucleus
- ACTH release
89
Growth Hormone- releasing hormone (GHRH)
- neuroendocrine cells of the arcuate nucleus
- GH release
90
Gonadotropin-releasing hormone (GnRH)
- neuroendocrine cells of the preoptic area
- FSH and LH release
91
Prolactin-inhibitory hormone (PH or dopamine)
- neuroendocrine cells of the arcuate nucleus
- inhibition of prolactin release
92
Growth hormone - inhibitory hormone (GIRH, Somatostatin)
- neuroendocrine cells of the periventricular nucleus
- inhibition of GH and TSH release
93
The six hormones secreted in the Anterior pituitary
- Growth hormone (GH) (tropic)
- Prolactin
- Thyroid-stimulating hormone (TSH) (tropic)
- Adrenocorticotropic Hormone (ACTH) (tropic)
- Follicle- stimulating hormone (FSH) (tropic)
- luteinizing hormone (LH) (tropic)
94
tropins
stimulate other glands to secrete their hormones
95
tropic hormones
promote growth and maintain size of target tissues and organs
- high blood levels cause target to hypertrophy
- low levels cause atrophy
96
growth hormone (GH)
- has direct actions on metabolism and indirect growth- promoting actions through insulin-like growth factor
97
GH release or inhibition chiefly regulated ____________ ___________
hypothalamic hormones
98
What are GH's direct actions on metabolism?
- glucose-sparing actions decrease rate of cellular glucose uptake and metabolism (anti-insulin effects)
- triggers liver to break down glycogen into glucose (glycogenolysis)
- increase blood levels of fatty acids for use as fuel (lipolysis)
99
Growth hormone-releasing hormone (GHRH)
- stimulates GH release
- triggered by low blood GH
- hypoglycemia (low blood glucose)
- high amino acid levels
100
Growth hormone- inhibiting hormone (GHIH) (somatostatin)
- inhibits release
- triggered by increase in growth hormone and insulin-like growth factor levels (negative feedback)
101
study slide 54
102
gigantism (children)
hypersecretion of growth hormone usually caused by pituitary tumor
103
acromegaly
overgrowth of hands, feet, and head
104
Hyposecretion of GH
in children results in pituitary dwarfism
- in adults usually causes no problems
105
Thyroid- Stimulating Hormone (TSH) - anterior pituitary gland
- stimulates normal development and secretory activity of thyroid
- release triggered by thyrotropin-releasing hormone (TRH) from hypothalamus
- inhibited by rising blood levels of thyroid hormones that act on both pituitary and hypothalamus
106
study slide 57 of lecture 1
107
Prolactin (PRL) (anterior pituitary gland
- stimulates milk production in females; role in males not known
108
What hormone controls regulation of prolactin?
- prolactin-inhibiting hormone which is dopamine
109
PIH prevents the release of PRL until necessary which leads to.....
lactation
110
What stimulates PRL?
increased estrogen levels stimulate prolactin
- breast swelling and tenderness during menstrual cycle
- suckling stimulates PRL release and promotes continued milk production
111
Adrenocorticotropin hormone (ACTH) (anterior pituitary gland)
- stimulates adrenal cortex to release cortisol, mineralocorticoids, and androgens
112
How is ACTH release regulated?
- triggered by hypothalamic corticotropin-releasing hormone in daily rhytym (highest levels in the morning)
113
Internal and external factors that alter release of corticotropin-releasing hormone (CRH)?
fever, hypoglycemia, and stressors
114
Follicle- stimulating hormone(FSH) and Luteinizing Hormone (LH)
also known as gonadotropins
115
FSH (follicle-stimulating hormone)
stimulates the production of gametes (egg or sperm)
116
LH (Luteinizing hormone)
- promotes production of gonadal hormones
- in females helps mature follicles of egg, triggers ovulation, and release of estrogen and progesterone
- in males production of testosterone
117
What hormones are absent from blood in prepubescent boys and girls?
follicle stimulating hormone (FSH) and Luteinizing hormone (LH)
118
negative feedback control slide 62
119
How are hormones transported?
Through the blood
120
Study the anatomy of the thyroid gland
121
Thyroid hormones T4 and T3
Body's major metabolic hormone
122
T4 (thyroxine)
consists of two tyrosine molecules with four bound iodine atoms (must be converted to T3 at tissue level)
123
T3 (triiodothyronine)
has two tyrosines with three bound iodine atoms
124
Thyroid hormone synthesis requires how much of iodine?
150 picograms
125
Thyroid gland secretes 80% T4 which is then converted to the active ____________ form at the ________________
T3 form at the tissues
126
Two mechanisms of the thyroid hormone:
1) Genomic actions through regulation of gene transcription
2) Non-genomic actions through metabolic activities
127
steps of the metabolic acivities:
- enters cell
- binds to receptors within nucleus
- triggers transcription
- increases metabolic rate and heat production
- regulates tissue growth and development
128
How does the thyroid hormone affect the lung?
increased ventilation
129
how does the thyroid hormone affect the liver?
increased basal metabolic
130
how does the thyroid hormone affect the heart?
increased heart rate, increased force of contraction, increased cardiac output
131
how does the thyroid hormone affect the adipose?
increased lipolysis
132
How does the thyroid hormone affect muscles?
increased protein catabolism
133
how is thyroid hormone regulated?
negative feedback
134
Hyperthyroidism
caused by an excess of thyroid hormones
Graves disease (autoimmune)
weight loss, heat sensitivity, increased appetite, heart rate, tremors, and nervousness
135
hypothyroidism
caused by a deficiency of thyroid hormones
often due to iodine deficiency
loss of functional thyroid tissue
weight gain, cold sensitivity, lethargy, metal fatigue
136
goiter
a diffuse enlargement of the thyroid gland, caused by a prolonged elevation of TSH
137
Thyroid nodule
a focal enlargement of a portion of the gland, caused by a benign or malignant neoplasm
138
Myxedema
swelling of the skin and underlying tissues (edema), low metabolic rate, feeling chilled
139
how to treat graves' disease
include surgical removal of thyroid or radioactive iodine to destroy active thyroid cells
140
Calcitonin
produced by parafollicular (C) cells in response to high calcium levels
141
What does calcitonin do?
lowers blood calcium levels. Antagonist to parathyroid hormone (PTH)
142
Parathyroid gland
four to eight tiny yellow-brown glands embedded in the posterior aspect of thyroid
143
Parathyroid cells secrete....
parathyroid hormone (PTH)
144
What is the most important hormone in calcium homeostasis?
PTH
145
When is PTH secreted?
in response to low blood levels of calcium, and inhibited by rising levels of calcium
146
What is the effect of PTH on bone?
increased resorption
147
What is the effect of PTH on the kidney?
increased calcitriol (Vitamin D)
148
what is the effect of PTh on the intestine?
increased calcium reabsorption
149
Adrenal gland
paired, pyramid-shaped organs atop kidneys
- structurally and functionally it is two glands in one
150
adrenal cortex anatomy
three layers of glandular tissue that synthesize and secrete several different hormones
151
adrenal medulla anatomy
nervous tissue that is part of sympathetic nervous system, secretes adrenaline
152
study the anatomy of the adrenal glands
153
The adrenal cortex is the area of the adrenal gland that produces....
corticosteroids
154
Zona glomerulosa produces..
mineralocorticoids
155
zona fasciculata produces...
glucocorticoids
156
zona reticularis produces...
gonadocorticoids
157
Mineralocorticoids
regulate electrolyte concentration in extracellular fluid
158
aldosterone
most potent mineralocorticoid
- simulations Na reabsorption by kidneys and Potassium elimination by kidneys
- regulation of log term blood pressure
159
Glucocorticoids
- influence metabolism of cells
- help resist stress
- maintain cellular concentrations of enzymes to produce glucose between meals
160
cortisol (hydrocortisone)
only glucocorticoid in significant amounts in humans
161
Cortisol is released in response to>>>
ACTH
acute stress interrupts cortisol rythm
162
Medullar chromaffin cells
synthesize catecholamines epiniphrine and norepinephrine
163
effects of catecholamines
- vasoconstriction
- increased heart rate
- increased blood glucose levels
- bronchial dilation
164
Gonadocorticoids (adrenal sex hormone)
weak androgens (male) converted to test, some to estrogen
- sex drive in women
- onset of puberty
- source of estrogens in postmenopausal
165
hypersecretion
- adrenogenital syndrome
- not noticable in adult males
- Boys- organs mature
females- facial hair, masculine pattern of body hair
166
Pineal Gland cells
secrete melatonin, derived from seratonin
167
melatonin affects:
day/ nigh cycles, sleep
physiological processes that show rhythmic variations (body temp, apetite_
168
the Pancreas
- triangular gland located partially behind the stomach
169
Acinar cells (exocrine)
produce enzyme-rich juice for digestion
170
Pancreatic islets
alpha cells produce glucagon
beta cells produce insulin
171
Glucagon
triggered by decreased blood glucose
extremely potent hyperglycemic protein hormone
raises blood glucose by telling liver to glycogenolysis and glucogenesis
172
glycogenolysis
break down glycogen into glucose
173
gluconeogenesis
synthesize glucose from lactic acid and other non-carbohydrates
174
Insulin
- secreted when blood glucose levels increase
175
how does insulin lower blood glucose
- enhance membrane transport of glucose into fat and muscle
- polymerize glucose to glycogen
- converts glucose to fat
176
Diabetes mellitus
Type 1: hyposecretion of insulin
Type 2: Hypoactivity of insulin
177
Glycosuria
excess glucose is spilled into urine
178
Polyuria
huge urine output
179
polydipsia
excessive thirst
180
polyphagia
excessive hunger and food consumption
181
Ketoacidosis
build up of ketones in the blood
182
untreated ketoacidosis...
causes disrupted heart activity, severe depression of nervous system that can lead to coma and death
183
Hyperinsulinism
excessive insulin secretion
- causes hypoglycemia: low blood glucose levels
184
"Insulin shock"
disorientation, unconsciousness, death
185
Gonads and placenta
produce same steroid sex hormones as those of adrenal cortex in greater amounts
186
Ovaries produce
estrogen and progesteron
- progesterone causes breast development and period
187
Testes
produces testosterone
- maturation of male
- necessary for normal sperm production
188
Placenta
secretes estrogens, progesterone, and human chrionic gondotropin to support pregnancy
189
