endocrine Flashcards
1
Q
what are hormones?
A
they are chemical messengers produced by endocrine glands and they regulate metabolic function of the cells in our body
elicits a specific response in distant target tissues
2
Q
how are hormones transported to target cells?
A
by the circulation or blood at a very low concentration
3
Q
how does hormone work on target cells?
A
the hormone enters the blood stream and is distributed throughout the entire body and there are receptors on tissues for example on skeletal muscle tissue then when the hormones get there binding occurs and hormonal effects appear
4
Q
what are the 4 major chemical classes of hormones?
A
amines
peptides
glycoproteins
steroids
5
Q
what are amine hormones?
A
they include:
catecholamines (dopamine, epi and norepi)
thyroid hormones(T3 & T4) and melatonin
6
Q
amine hormones are derived from?
A
amino acid called tyrosine and tryptophan
7
Q
amine hormones are secreted by?
A
adrenal medulla, thyroid and pineal glands( melatonin)
8
Q
____are the largest group of hormones?
A
peptide hormones
9
Q
where are peptide hormones synthesized in?
A
in the rough endoplasmic reticulum of endocrine cells as an inactive preprohormones
10
Q
list peptide hormones
A
hypothalamus: all releasing hormones
pituitary gland: ACTH, GH, MSH, ADH, prolactin and oxytocin
pancreas: insulin and glucagon
parathyroid gland: parathyroid hormone
C cells of the thyroid gland: calcitonin
11
Q
what are glycoprotein hormones?
A
they contain long polypeptide bound to one or more carbohydrate groups
12
Q
list glycoprotein hormones
A
TSH
FSH
LH
13
Q
where does steroid hormones come from?
A
they are synthesized from cholesterol
14
Q
list steroid hormones
A
cortisol
aldosterone
testosterone
estrogen
progesterone
15
Q
features of steroid hormones?
A
they are not stored in vesicles and rapidly diffuse out of the cell once they are synthesized due to their high lipid solubility
they require carrier proteins in the blood due to their low water solubility
16
Q
what are other organs that produce hormones?
A
placenta: HCG or human chorionic gonadotropin
heart: ANP or atrial natriuretic peptide
stomach: gastrin
small intestine: CCK, secretin
kidney: renin, 1-25-dihydroxycholecalciferol and erythropoietin
fat cells/ adipose tissue: leptin or adipokines
GIT: ghrelin
17
Q
what does hCG do?
A
it maintains corpus luteum early in pregnancy
18
Q
what does atrial natriuretic peptide do?
A
it reduces blood pressure, blood volume and blood sodium concentration
it also increases renal Na+ excretion
19
Q
what does gastrin do?
A
it stimulates HCl secretion by parietal cells of gastric mucosa
20
Q
what does CCK do?
A
it stimulates release of pancreatic enzymes
contracts gallbladder
relaxes sphincter of oddi
inhibits stomach motility or delay gastric emptying
21
Q
what does secretin do?
A
increases fluid and HCO3 secretion by pancreatic duct
feedback inhibition of gastric H+ secretion
22
Q
what does renin do?
A
it cleaves circulating angiotensinogen to angiotensin I
23
Q
what does 1-25-Dihydroxycholecalciferol do?
A
it stimulates gastrointestinal Ca2+ and phosphate absorption
24
Q
what does erythropoietin do?
A
it stimulates RBC production
25
what does leptin do?
it activates satiety center of hypothalamus which suppresses appetite
26
what does ghrelin do?
it activates hunger center of the hypothalamus which stimulates appetite
27
where is the receptors for steroids hormone located?
in cytoplasm
28
where is the receptor for thyroid hormones located?
on the nucleus
29
where is the receptor for protein, peptide and catecholamines hormones located?
on the surface of cell membrane
30
true or false: hormones can act directly on target cells
false, hormones never act directly they need to combine with specific receptors
31
what are receptors?
they are large protein molecules and they are present either on the surface of cells or inside a cell like the cytoplasm or in nucleus
32
cells give a response to a particular hormone if only there's---?
if only there's specific receptors for that hormone
33
what are first messengers?
are extracellular factors, often hormones or neurotransmitters, such as epinephrine, growth hormone, and serotonin
34
the binding of a hormone to it's receptor causes the generation of intracellular signaling molecules called___
second messengers
35
what are second messengers
are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers.
36
what does second messengers do?
they amplify the hormonal signal within the target cells
-> they trigger physiological changes at cellular level such as proliferation, differentiation, migration, survival, apoptosis and depolarization.
37
second messengers use___ to bring changes in cellular activity
the stimulation of kinases
38
what are kinases?
they are enzymes that phosphorylate target proteins
39
list common second messengers
cAMP
DAG and IP3
cGMP
Ca2+
40
explain how cAMP is a second messenger
1. the hormone receptor complex associates with intracellular heterotrimeric G proteins
2. this combination activates adenylyl cyclase protein enzyme which is also located in the membrane also but a large portion of it protrudes in the cytoplasm
3. the activated adenylyl cyclase convert ATP into cAMP
4. cyclic AMP activates cytoplasmic protein kinases
5. activated protein kinases which affects cellular activity through phosphorylation of the effector proteins
the cAMP signal is terminated when cAMP is broken down by the action of a phosphodiesterase enzyme
41
what does hypothalamus do?
->it receives signals from almost all sources in NS
->it acts as a collecting center for internal body
informations
->it control secretion of pituitary gland hormones
42
what controls the pituitary gland?
by releasing hormones of the hypothalamus
and by target hormones which is negative FB system
43
why is the pituitary called the master gland
because it control different peripheral target glands
44
what is the hypothalamic pituitary axis?
is an intricate pathway with a central role in maintaining homeostasis by integrating complex physiological and endocrine inputs, and neuronal and hormonal output
45
___is a well studied interface between the nervous system and endocrine system
hypothalamic pituitary axis
46
what are the organs that are directly or indirectly affected by the axis?
reproduction
growth
lactation
stress response
metabolism
water balance
immune system
47
48
what are the 2 connections of the hypophyseal pituitary axis?
vascular connection and neural connection
49
which has organ has vascular connection?
the anterior pituitary lobe
50
which organ has a neural connection?
the posterior pituitary lobe
51
the vascular connection is between?
the hypothalamic and the hypophyseal portal circulation
52
what does the vascular connection in anterior pituitary lobe do?
hormonal regulation by releasing hormones of the hypothalamus and by feedback from the target gland hormones
53
the neural connection is between?
the hypothalamic and the hypophyseal tract
54
the neural connection is regulated by?
the neuroendocrine reflex
55
the hormones secreted by the anterior pituitary are called?
trophic hormones
56
high anterior pituitary hormones cause their target organs to be___
hypertrophy
57
low concentration of anterior pituitary hormones cause their target organs to be___
atrophy
58
GH is released from?
somatotroph cells of the anterior pituitary glands
59
what does GH control of release?
GHRH+ and GHIH- of the hypothalamus
60
what is the target organ of GH?
most tissues
61
what are the actions of GH?
-> it stimulates protein synthesis and cell growth via somatomedins or IGF-1 released from liver
-> lipolysis and increased blood glucose
-> it causes growth of all tissues
-> it promotes hypertrophy and hyperplasia
62
how does GH promotes overall tissues and organ growth?
by promoting the movement of amino acids into cells and the incorporation of these amino acids into proteins
63
linear growth occurs indirectly through the stimulation of?
insulin like growth factor or IGF-1 secretion
64
___is the most important endocrine regulator of final body size
GH
65
how does GH exerts effect on bones?
it causes liver to form somatomedins or IGF that strongly increases all aspects of bone growth
66
how does somatomedins increase bone growth?
->by stimulating osteoblasts
->increased protein deposition by chondrocytic and osteogenic cells
67
what are the metabolic effects of GH?
effects on protein metabolism
effects on fats
effects on CHO
68
list the effects on GH in protein metabolism
increases transport of a.a through cell membrane
increase protein synthesis by ribosome
decreases protein catabolism
it stimulates nucleus for formation of RNA
so GH increases protein synthesis
69
70
how does GH have effect on fats?
it has a lipolytic effect or gives energy
71
effects of GH on CHO?
it has diabetogenic effect, which means its anti insulin action and it increases blood glucose
72
list the effect of GH on CHO
decrease glucose utilization in muscle
decrease number of insulin receptor
decrease glucose uptake by the cells
enhance gluconeogenesis in the liver
73
what are defects in GH secretion in childhood?
gigantism and dwarfism
74
what are defects in GH secretion in adulthood?
acromegaly
75
what is gigantism?
it is caused by GH excess
76
77
what does gigantism result in?
it increase linear height because the epiphyseal growth plates in the long bones are open
78
what's the cause for gigantism?
a GH secreting pituitary tumor
79
what is dwarfism?
it is GH deficiency
80
what does dwarfism result in?
short stature and growth retardation
81
what is acromegaly
it's GH excess in adults
82
what causes acromegaly?
excess secretion of GH after puberty
83
what are the characteristics of acromegaly
linear height is fixed due to closure of the growth plates in long bones
the hands, feet, jaw, forehead and nose continue to grow giving patients a characteristic appearance
84
why is GH excess associated with hyperglycemia?
its likely to cause DM due to the anti insulin actions of GH
85
from where is the thyroid stimulating hormone released?
from thyrotroph cells of anterior pituitary
86
what is the control of release of TSH?
TRH of the hypothalamus and coldness+
T3 and T4- and negative FB
87
what is the target organ of TSH?
thyroid gland
88
what is the action of TSH?
->it stimulates the thyroid gland to produce and secrete thyroxine T4 or triiodothyronine T3
->it maintain the structural integrity of the thyroid gland
89
from where is the adrenocorticotropic released?
the corticotroph cells of the anterior pituitary gland
90
what is the control of release of ACTH?
CRH of the hypothalamus +
glucocorticoids - and negative FB
91
what is the target organ of ACTH?
adrenal cortex
92
what is the action of ACTH?
->it stimulates the adrenal cortex to secrete glucocorticoids like hydrocortisone or cortisol
->it promotes structural integrity of the adrenal cortex
93
where is follicle stimulating hormone released from?
from gonadotroph cells of the anterior pituitary glands
94
what is the control of release of the FSH?
GnRH of the hypothalamus+
prolactin, estradiol and inhibin-, negative FB+ prolactin
95
what is the target organ of the FSH?
gonads
96
what is the action of the FSH?
->it acts on testicular Sertoli cells in the male and follicular granulosa cells in the female
->stimulates the growth of ovarian follicles + production of estrogen in females
-> stimulates the production of sperm cells which is spermatogenesis via Sertoli cells of the testis of males
97
from where is luteinizing hormone released from?
released from gonadotroph cells of the anterior pituitary glands
98
what is the control of release of LH?
GnRH of the hypothalamus+
prolactin, testosterones and negative FB
before ovulation+ and after ovulation- it releases estradiol
99
what is the target organ of LH?
gonads
100
what is the action of LH?
-> it stimulates ovulation and the conversation of the ovulated ovarian follicle into an endocrine structure called a corpus luteum in females
-> stimulates the secretion of male sex hormones mainly testosterones from the interstitial cells or Leydig cells in the testes
101
from where is the prolactin released?
from lactotroph cells of the anterior pituitary glands
102
what is the control of release of PRL?
-> inhibited by PIH, prolactin inhibiting hormone dopamine
->secretion increases during pregnancy and peaking near the time of parturition
-> sucking and tactile stimulation of the nipples increase the secretion
->negative FB mechanism facilitates the secretion of dopamine and regulate it's own secretion
103
___inhibits the effects of gonadotropins and prevent ovulation in lactating women
PRL
104
what is the action of PRL?
-> stimulation of milk production by the mammary glands of women after the birth of a baby and mammary gland development
-> negative FB regulation of gonadotropins which are FSH and LH
->acts on the kidneys to help regulate water and electrolyte balance
105
clinical correlates to PRL?
hyperprolactinemia and hypoprolactinemia
106
hyperprolactinemia can occur form?
overproduction or loss of the dopamine inhibitory effect
107
the overproduction of PRL can be from?
a prolactin secreting pituitary adenoma
108
in hyperprolactinemia the loss the dopamine inhibitory effect can be from?
use of antipsychotic drugs or damage to the pituitary stalk
109
what is the key clinical indicator of hyperprolactinemia?
galactorrhea or milky nipple discharge
110
hypoprolactinemia can occur due to?
with other adenohypophysial deficiencies
111
the clinical effect of hypoprolactinemia is?
inhibition of lactation
112
what is the other name of GH?
somatotropin
113
what is the other name for TSH?
thyrotropin
114
what is the other name for ACTH?
corticotropin
115
what is the other name for FSH?
folliculotropin
116
what is the other name for LH?
luteotropin
117
which hormones are released from the gonadotroph cells of anterior pituitary?
FSH and LH
118
119
say something about hormones of neurohypophysis
Antidiuretic hormone and oxytocin are mainly synthesized in neuros cell bodies that originate in the supraoptic nucleus and paraventricular nucleus of the hypothalamus and then they are stored in the posterior pituitary
120
what is the control of release of ADH
neuroendocrine reflex
->ADH+ released in low levels of water like dehydration and decrease blood volume and pressure and it increase osmolar pressure detected by hypothalamus
->ADH- released to increase blood volume and BP to normal level
121
what is the target organ of ADH?
kidney tubules and blood vessels
122
what is the other name of ADH?
vasopressin
123
what is the action of ADH?
-> it has constricting effect on afferent arterioles so when it decreased GFR the urine output will also decreases
-> it increases the reabsorption of water at the collecting duct and collecting tubules
->it promotes aldosterone production from adrenal cortex
124
how does ADH promotes aldosterone production from adrenal cortex?
by Na+ retention and K+ excretion
125
how does ADH respond to decrease blood volume and pressure?
by increasing fluid retention at the kidney
and by increasing blood pressure through vasoconstriction
126
what happens when someone has ADH deficiency?
it results in the formation of dilute urine in which urine osmolarity will be less than that of plasma
127
the condition in which urine osmolarity will be less than that of plasma is called?
central diabetes insipidus
128
ADH deficiency will cause
dilute urine output
129
what is the control of release of oxytocin?
it also has neuroendocrine reflex
->during late pregnancy or trimester period and tactile stimulation of the mammary gland and sex organs
in nursing mothers the mechanical stimulus of sucking acts it will stimulate the reflex secretion of oxytocin via sensory nerve impulses to the hypothalamus
130
what is the target organ of oxytocin?
uterus and mammary gland
131
what is the action of oxytocin?
->it stimulates uterine contraction, it acts on the target cells by increasing the intracellular Ca+ content which leads to muscle contraction
-> it stimulates milk ejection from the lactating breast
->it promotes maternal behavior toward the neonate
132
how is oxytocin used clinically?
used for induction of labor if they pregnancy is prolonged
or in the case of severe pregnancy induced hypertension or preeclampsia
133
explain the mechanism of action of oxytocin on uterine smooth muscle contraction
-> oxytocin increases late in pregnancy causing a powerful uterine contraction response during labor
->distention of the uterine cervix stimulates the release of oxytocin via the neuronal pathway
->the uterine contractions that result further cervical distension
-> a cycle of positive feedback develops during the later stages of labor in which progressive cervical distention stimulates more oxytocin release
-> this cycle terminates with the birth of the infant
134
what are the 2 cells of thyroid gland?
follicular and para follicular cells
135
what's the function of follicular cells of thyroid gland?
it synthesizes and secretes the principal thyroid hormones T4 and T3
136
what is the ratio of T4 and T3?
4:1
137
which thyroid hormone is the most biologically active?
T3
138
what is the function of para follicular cells?
it synthesizes and secretes calcitonin
139
why does the thyroid hormones have wide spread effect?
because it has calorigenic action which is stimulating oxygen consumption
140
through the activation of genes thyroid hormones stimulate...?
-> protein synthesis
->promote maturation of the nervous system
-> increase the rate of cell respiration in most tissues
->they are need for proper growth and development
141
what are the metabolic functions of thyroid hormones?
->are primarily responsible for determining the BMR, it either increase the BMR and oxygen consumption of most of tissues of the body
-> they increase synthesis of many intracellular enzymes and increase activity of Na+ K+ and ATPase which increase the rate of transport of both Na+ and K+ through the cell membrane, this process utilized energy and increase heat production
142
what's the action of thyroid hormones on mitochondria?
they increase the size, number and activity of mitochondria which will increase the rate of formation of ATP to enhance cellular function
143
what's the action of thyroid hormones on ribosomes?
->they increase the rate of formations of proteins by the ribosomes via mRNA
->they increase mRNA synthesis by the genes which leads to a generalized increase in synthesis of many types of protein within the cells
-> large amount of thyroid hormone lead to excess catabolism of muscle protein
144
what's the action of thyroid hormones on carbohydrate metabolism?
-> it increases the rate of absorption of carbohydrate from the GIT
-> they enhance glucogenesis and glycolysis
-> they increase enzymes acting on carbohydrates metabolism
145
what happens after carbohydrate meals and what's thyroid association here?
blood glucose level increases but it normally falls again rapidly because of the rate of glucose utilization is also increased
146
the effects of thyroid on carbohydrate results from?
increases in the activity of enzymes
147
what's the action of thyroid hormones on fat metabolism?
-> all aspects of fat metabolism are increased including synthesis, mobilization and utilization
-> it accelerates the oxidation of fatty acids by the cells
->it lowers the level of cholesterol, phospholipids and triglycerides in the blood
148
as thyroid hormone accelerates the oxidation of fatty acids by the cells so this means?
more lipolytic effect than lipogenic effect
149
what's the action of thyroid hormones on skeletal growth and development?
->due to its protein synthesis by ribosomes its important for normal growth of soft tissues and skeleton
-> its required for production and action of GH and insulin like growth factors on skeleton growth and development
150
what's the action of thyroid hormones on fetal and neonatal nervous system?
->it promote growth and development of the brain during fetal life and for the first few years of life
-> essential for normal myelination and development of the NS in infant
151
if there's thyroid hormone deficiency what is its effect on infants?
-> growth and maturation of the brain s retarded
-> myelination is defective
-> the reflex time prolonged
152
if there's thyroid hormone excess what is its effect on adults?
-> it causes an increased response of the brain to catecholamines and increases activation of reticular activating system
-> restlessness and hyper excitability
153
what's the action of thyroid hormones on the cardiovascular system?
-> increase the number and affinity of beta-1 adrenergic receptors in the heart
-> it increases the heart sensitivity to catecholamine and catecholamine increases all properties of the heart
->increased metabolism in the tissues causes more rapid utilization of oxygen and causes greater metabolic end products to be released from the tissues
->these effects cause vasodilation thus increasing the rate of blood flow in the skin for heat elimination
->increase blood flow leads to increase venous return leading to increase in CO and systolic blood pressure
154
what's the action of thyroid hormones on respiration?
->increase respiration due to increase rate of metabolism which increase the utilization of oxygen and formation of carbon dioxide
-> helps in dissociation of oxygen from hemoglobin by increasing the amount of 2,3 diphosphoglyceride in the RBC
155
what's the action of thyroid hormones on GIT?
-> they increase the rate of secretion of the digestive juice and motility which leads to increased appetite and food intake
156
what's the action of thyroid hormones on sexual functions?
-> normal amount is important for normal sexual function
-> essential for normal menstrual cycle and fertility
-> increase milk secretion in lactating women
157
thyroid malfunction is very common in which gender?
more prevalent in females
158
159
hyperthyroidism results from?
a secretory tumor of the thyroid gland or from an autoimmune condition as in graves diseases
160
what happens in graves diseases?
thyroid stimulating immunoglobulin are produced by the immune system
and these are agonists at the TSH receptor causing both hypersecretion and growth of the gland causing a goiter
161
what causes hypothyrodism?
inadequate production of thyroid hormones due to sufficient dietary iodine
162
inadequate amounts of T4 and T3 causes?
abnormally high levels of TSH secretion with lack of negative feedback inhibition which in turn stimulates the abnormal growth of the thyroid
163
hypothyroidism is usually a problem in?
a problem in thyroid gland and not with pituitary production of TSH
164
list the causes for goiter
-> iodine deficiency
-> anti thyroid drugs
-> thyroidal enzyme defects
all these cause decrease in T3, T4 synthesis and secretion and increase in TRH and plasma TSH
165
what is the other name for para follicular cells?
C cells
166
where are C cells found?
scattered outside of follicle epithelium
167
what is the function of calcitonin?
->lowers blood Ca+ levels
->inhibits osteoclasts cells of bones+
->stimulates osteoblast cells of bone
->increases urinary calcium loss
168
the secretion of calcitonin is triggered by?
high blood Ca+ level
169
what is parathyroid gland?
they are 4 glands embedded on posterior side of thyroid gland
170
___cells produce parathyroid hormone
chief cells
171
what is the control of secretion of PTH?
-> lowers blood Ca+ level
-> it act on bones osteoclast cells for bone resorption
->acts on GIT dietary absorption of Ca+
->act on kidneys to decrease Ca+ loss via renal excretion
172
what is PTH action?
it raises blood Ca+ to normal level
173
where is the adrenal glands located anatomically?
situated on superior border of each kidney surrounded by fibrous capsule
174
what are the 2 parts of adrenal gland?
the outer adrenal cortex and the inner adrenal medulla
175
the outer glandular region has__ layers
3 layers and the cells of the last 2 act as a single unit
176
what does the glandular region of outer adrenal cortex secretes?
->aldosterone
->cortisol
->sex hormones like androgen and estrogen
177
what does the neural tissues of an inner medulla secretes?
release catecholamines, 80% epi and 20% norepi
178
what are the 3 layer of adrenal cortex?
->zona glomerulosa, yehe outermost nw
-> zona fasiculata, middle
->zona reticularies, inner most
179
what does the zona reticularies of adrenal cortex secretes?
secretes glucocorticoids mainly cortisol and androgens
180
which adrenal gland doesn't have nerve supply?
adrenal cortex
181
what does the zona glomerulosa produce?
the principal physiological mineralocorticoid hormone aldosterone
182
what the function of aldosterone?
->promotes the renal tubular reabsorption or retention of Na+
->secretion or excretion of K+ and H+
->it has major role in the maintenance of electrolyte and fluid balance and regulate mineral content in blood volume, water and electrolyte balance
183
the stimulation of aldosterone is triggered by?
decreased Na+
increased K+
decreased blood volume
BP and stress
184
the secretion of aldosterone is regulated by?
by renin, ADH and ACTH
185
what is the target organ of aldosterone?
renal tubules
186
aldosterone control of secretion is?
->high K+ of ECF detected by JGA and activated renin
-> low Na+ of ECF detected by hypothalamus and activate CRH and then ACTH which will release aldosterone and cortisol
-> dehydration which is detected by hypothalamus and activates ADH
187
what does the zona fasiculata produce?
glucocorticoids like cortisone and cortisol
188
glucocorticoids are released due to?
in response to ACTH
189
what's the function of glucocorticoids?
->helps to resist long term stressors
->promote normal cell metabolism
190
prolonged ACTH secretion results in?
hypertrophy and hyperplasia of the adrenal cortex
191
what are actions of glucocorticoids?
-> are essential to give relief from prolonged stressors
-> increase gluconeogenesis
-> increase protein catabolism in muscle and decrease protein synthesis by providing more a.a to the liver for gluconeogenesis
->decrease glucose utilization and insulin sensitivity of adipose tissue
-> increase lipolysis which provide more glycerol to the liver gluconeogenesis
192
what are the anti inflammatory effects of glucocorticoids?
-> induce the synthesis of lipocortin which is an inhibitor phospholipase A
->inhibit the production of interleukin 2 and inhibit the proliferation of T- lymphocyte
->inhibit the release of histamine, serotonin from mast cells and platelets
it suppresses immune response
193
what is Cushing's syndrome?
it's excess of glucocorticoids
194
hypercortisolism is characterized by?
-> hyperglycemia due to enhanced gluconeogenesis
->muscle wasting and weakness due to protein catabolism
->truncal obesity and rounding of the face or moon face
->hypertension is common due to mineralocorticoid effects of excess glucocorticoids
195
what is Addison's diseases?
caused by hyposecretion of corticosteroids especially glucocorticoids
196
what causes the pigment in Addison's diseases?
results from stimulation of melanocytes by ACTH which is structurally similar to MSH
197
zona fasiculata is more or less similar to___
zona reticularies
198
what is the function of zona reticularies?
-> to form glucocorticoids cortisol and corticosterone
->and form lesser extent of androgens and estrogens
199
adrenal medulla is innervated by?
preganglionic nerve fibers of sympathetic NS and axons stimulate hormone secretion
200
what's the function of adrenal medulla hormones?
-> increase heart rate and force releases glucose and fatty acids into blood and opens airways
they prepare the body to deal with short term stress
201
the release of catecholamines by adrenal medulla is controlled by?
preganglionic sympathetic neurons
Ach is released and acts at the nAchR of the chromaffin cells
202
what happens during the stress response?
it is sensed in the hypothalamic pituitary adrenocortical axis sustains epi secretion by the adrenal medulla
203
what is the target cell for adrenal medulla hormones?
most cells
204
what are the effects of adrenal medulla hormones?
->increase cardiac activity, blood pressure, glycogen breakdown, and blood glucose level and release of lipids by adipose tissue
205
where is the pancreas located?
behind stomach and beneath liver
206
pancreas has both ___ and ___
cells
exocrine and endocrine cells
207
endocrine cells of the pancreas are organized into__
islets of langerhans
208
what does islets of Langerhans secretes?
insulin and glucagon
209
insulin is produced by which cells of the islets?
beta cells
210
glucagon is produced by which cell of the islets?
alpha cells
211
exocrine cells of the pancreas secrete?
pancreatic juice and digestive enzyme
212
what is the action of insulin?
-> lowers blood glucose concentration
-> increased glucose uptake, storage and use by target cells
213
what is the target cell for insulin?
liver, muscle and fat cells
214
what is the action of glucagon?
-> it raises blood glucose concentration
->increases glycogen breakdown and glucose synthesis
215
what is the target cell of glucagon?
liver cells
216
what is the role of glucagon in carbohydrate metabolism?
->it stimulates hepatic glycogeneolysis which increases blood glucose
217
what is the role of glucagon in lipid metabolism?
->stimulates lipolysis which increases the release of free fatty acid and glycerol from adipose tissue
->increase hepatic ketogenesis and facilitates the conversion of fatty acids to keton bodes
218
what is the role of glucagon in protein metabolism?
-.has catabolic effect on hepatic protein and inhibit the incorporation of amino acids into hepatic protein
219
what is the role of insulin in carbohydrate metabolism?
-> lowers the level of blood glucose by increasing the transport and peripheral utilization of glucose
->increases muscle and liver glycogen
220
what is the role of insulin in protein metabolism?
-> strongly anabolic effect alew, it synthesizes protein and inhibit protein catabolism
-> increase the incorporation of a.a into protein by accelerating the entry of a.a into cells
221
what is the role of insulin in lipid metabolism?
-> inhibit the breakdown of triglycerides and stimulates the formation of triglycerides
->accelerates synthesis of fatty acids and glycerol phosphate and leading into increased deposition of triglycerides in adipose tissue
222
____is insulin excess
insulinoma
223
insulinoma results from?
adenoma of the islets
224
what is the treatment of insulinoma?
surgical removal of the tumor
225
____is deficiency of insulin
diabetes mellitus
226
define DM
a chronic disorder of carbohydrate, fat and protein metabolism
227
DM is characterized by?
hyperglycemia and commonly glycosuria which is sugar in urine
228
what's the cause of DM?
relative or absolute deficiency of insulin
229
what is known as the most endocrine abnormality?
DM, it has 4% of incidence
230
type 1 and 2 DM onset
sudden
gradual
231
type 1 and 2 DM age at onset
any age
mostly in adults
232
type 1 and 2 DM body habitus
thin or normal
often obese
233
type 1 and 2 DM ketoacidosis
common
rare
234
type 1 and 2 DM autoantibodies
usually present
absent
235
type 1 and 2 DM endogenous insulin
low or absent
normal which is increased or decreased
236
type 1 and 2 DM concordance in identical twins
50%
90%
237
type 1 and 2 DM prevalence
less prevalent
more
238
what are the clinical signs of DM?
->polyuria which is huge urine output
->polydipsia which is excessive thirst
->polyphagia which is excessive hunger and food consumption
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____is excessive insulin secretion
hyperinsulinemia which results in hypoglycemia
