Exam 2 Flashcards

(359 cards)

1
Q

What are the two parts of the adrenal (suprarenal) glands

A

Cortex

Medulla

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2
Q

Function of cortex in the adrenal glands

A

Secretes corticosteroids derived from cholesterol

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3
Q

Function of medulla in the adrenal glands

A

Secretes catecholamines derived from tyrosine

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4
Q

Corticosteroids released from the adrenal cortex (3)

A
Glucocorticoids (eg- Cortisol)
Mineralcorticoids (ex- Aldosterone)
Sex steroids (testosterone)
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5
Q

Catecholamines secreted from the adrenal medulla (2)

A

Epinephrine and norepinephrine

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6
Q

Layers of the adrenal cortex (superficial to deep)

A

Zona glomerulosa
Zona fasciculata
Zona Reticularis

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7
Q

Layers of the adrenal glands

A

Capsule
Adrenal cortex
Adrenal medulla

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8
Q

Zona glomerulosa is ____% of the adrenal cortex thickness

A

15%

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9
Q

What does the Zona glomerulosa secrete? What is the primary hormone?

A

Mineralocorticoids

Primary hormone = aldosterone

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10
Q

What stimulates aldosterone release?

A

Angiotensin II and Potassium

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11
Q

Function of Aldosterone

A

Controls blood pressure and blood volume
Controls electrolyte balance through the kidney
Causes reabsorption of Na, Cl, H20
And excretion of K and H

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12
Q

______% of adrenal cortex thickness is the Zona fasciculata

A

75%

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13
Q

Zona fasciculata secretes:

Its primary hormone is:

A

Glucocorticoids

Primary hormone is cortisol (stress hormone)

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14
Q

The zona fasciculata is under what control?

A

Hypothalamic-pituitary axis control (CRH and ACTH)

Cortisol provides negative feedback to the hypothalamus and the anterior pituitary

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15
Q

______% of thickness in the adrenal cortex that is the zona reticularis

A

10%

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16
Q

What does the zona reticularis secrete?

Primary hormones?

A

Adrogens

DHEA (dehydroepiandosterone) and androstenedione

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17
Q

Zona Reticularis control mechanism is influenced by:

A

ACTH

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18
Q

Dihydrotesterone and estradiol synthesis occur where?

A

In peripheral tissues and gonads

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19
Q

How is pregnenolone made?

A

Cholesterol enters mitochondria of cells and is cleaved by cholesterol desmolase (P-450scc)

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20
Q

Rate limiting step in adrenal steroid production .

Why?

A

Synthesis of pregnolone

It can be converted into any of the other steroid hormones

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21
Q

Adrenal cholesterol is most provided by:

A

Blood LDL

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22
Q

Adrenal cholesterol is obtained by:

A

Receptor mediated endocytosis (rate influenced by ACTH)

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23
Q

______ release cholesterol from the endosomes

A

Lysosomes

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24
Q

Synthesis of hormones occurs where?

A

In mitochondria and ER

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25
Aldosterone- ____% of all mineralcorticoid activity. Very ___
90% | Potent
26
Mineralocorticoids (5)
``` Aldosterone Cortisol Corticosterone Cortisone Deoxycorticosterone ```
27
Aldosterone synthesis steps
``` Cholesterol To pregnenolone Progesterone 11-Deoxycortocosterone DOC Corticosterone 18 (OH) Corticosterone Aldosterone ```
28
Cortisol- ____% of ______ activity, very potent
95% glucocorticoid
29
Glucocorticoid minor in humans
Corticosterone
30
Glucocorticoids that are almost as potent as cortisol
Cortisone
31
Synthetic glucocorticoids
Prednisone (cortisol X 4) Methylprednisone (Cortisol X 5) Dexamethason (Cortisol X 30)
32
90-95% of cortisol is bound to: Some to: The rest:
Transcortin (cortisol-binding globulin) Some to albumin The rest (tiny amount) as free cortisol
33
Half life of cortisol
60-90 min
34
60% of aldosterone is bound to _____ 40 % : Half life is:
Albumin Free aldosterone 20 min
35
Transcortin is produced where?
In the liver
36
________ proteins slow hormone inactivation. They help maintain:
Trasport proteins Helps maintain hormones in circulation
37
All adrenal cortical hormones are metabolized to :
Inactive conjugated forms in the liver (mostly conjugated with glucuronic acid)
38
25% of inactive conjugated forms are excreted where? The remaining are excreted:
Into bile In the urine
39
Cortisol also binds to _________ receptors
Mineralocorticoids receptors
40
What has greater activity than cortisol?
Aldosterone (3000x greater)
41
Kidney has a receptor to metabolize ______ to _____
Cortisol to cortisone (11beta-hydroxysteroid) which nullifies most of cortisol’s mineralocorticoid effects there.
42
Aldosterone has effects on:
Sweat glands, salivary glands, intestinal epithelial cells
43
What are aldosterone’s effects on the kidney?
Increases renal tubular reabsorption of sodium and potassium secretion - especially in the principal cells of the distal tubules and collecting tubules Also stimulates secretion of H+ via H+/ATPase in the intercalated cells of collecting tubules
44
Aldosterone antagonists
Spironalctone | Eplerenone
45
Sodium channel blockers
Amiloride | Triamterene
46
ECT sodium concentration only ____ slightly with:
Rises Increased aldosterone secretion
47
What are physiologic mechanisms that keep sodium concentration for getting too high? What are these called?
Osmotic absorption of water Increased thirst and water intake Resulting volume/pressure increase stimulates pressure disrespect and natriuresis Called the “aldosterone escape”
48
Diseases of excess aldosterone
Hypokalemia | Alkalosis
49
Hypokalemia is due to: | It causes:
Increased loss of K+ in the urine and uptake into cells | Causes severe muscle weakness
50
Alkalosis is due to:
Stimulation of H+ pump in intercalated cells
51
Diseases of deficient aldosterone
Hyperkalemia NaCl depletion and blood volume depletion progressing to shock
52
Hyperkalemia is due to:
Retention of K+ in the ECF | Cardiac toxicity
53
How does aldosterone increase reabsorption of NaCl and secretion of K+?
By the ducts of the salivary glands and sweat glands (helps to conserve Na+ in times if increased secretion of sweat or saliva)
54
Where does aldosterone enhance Na+ absorption? What does this lead to?
By the intestines | Leads to the absorption water and Cl- (and other anions)
55
What would happen to the intestines without aldosterone
NaCl and water are unabsorbed which will lead to diarrhea
56
How does aldosterone enter the cell?
Diffusion
57
Receptor that binds with aldosterone
Mineralocorticoid receptor (MR)
58
After MR/aldosterone complex diffuses into the nucleus, what is induced?
DNA transcription into mRNA Which is then translated into proteins such as: Na+/K+ ATPase and epithelial sodium channels
59
What increases aldosterone secretion?
Increased K+ concentration in the ECF And Angiotensin II concentration in the ECF
60
What slightly decreases aldosterone secretion?
Increased Na+ ion concentration in the ECF
61
What is necessary for aldosterone secretion?
ACTH from the anterior pituitary gland | But it has little effect in controlling the RATE of secretion
62
At least 90% of glucocorticoid activity is due to:
Cortisol (aka hydrocortisone)
63
_____ provides a smaller amount of glucocorticoid activity?
Corticosterone
64
Cortisol effects what 4 things?
Carbohydrate metabolism Protein metabolism Fat metabolism Stress and inflammation resistance
65
Cortisol and carbohydrate metabolism stimulates:
Gluconeogenesis
66
Gluconeogenesis induces
Production of enzymes in the liver to convert amino acids into glucose Mobilization of amino acids from tissues outside liver (mainly muscle)
67
Newly made glucose is stored largely as:
Glycogen in the liver; access by epinephrine and glucagon as needed
68
Decreased glucose utilization by cells is likely due to
inhibition of NADH oxidation
69
Elevated blood glucose is due to:
The combined effects of gluconeogenesis and decreases glucose utilization of cells
70
Elevated blood glucose causes
Insulin secretion (Cortisol also decreases insulin sensitivity)
71
Excess in cortisol secretion causes:
Adrenal diabetes
72
Reduction of cellular protein (DOES/DOES NOT) occur in the liver. What does this do the protein?
Does not Decreases protein synthesis Increases protein catabolism
73
Excess of cellular protein can cause
Severe weakness
74
The liver (INCREASES/DECREASES) plasma protein production
Increases
75
Since plasma proteins are largely produced by the _______, they increase in the _______.
Liver | Blood
76
Increased blood amino acids decrease: They increase:
Decrease transport of amino acids into extrahepatic cells Increase release of amino acids into blood from protein catabolism
77
Amino acids in the liver are used for what?
To make plasma proteins, increase protein synthesis and for gluconeogenesis
78
Cortisol causes - Release of free fatty acids from: - increased _____ of fatty acids in cells
Adipocytes Oxidation
79
Excess cortisol leads to fat:
Accumulation in the face and torso
80
In regards to fat, glucose causes:
Decreased glucose utilization Decreased sensitivity to insulin Increased lypolysis Release of: Glycerol
81
In regards to muscle, increase of glucose causes:
Increase in: Protein degradation Decrease in: Protein synthesis Glucose utilization Sensitivity to insulin Release of: Amino acids
82
In the liver, increased amino acids and glycerol causes:
``` Increase in: Glycogen storage Gluconeogenesis Activity of enzymes Amounts of enzymes ``` Release of: Glucose
83
Types of stress (physical or neurogenic)
Trauma or surgery Infection of any debilitating disease Intense heat or cold Psychological distress
84
Stress causes increase in:
ACTH secretion which then increases cortisol secretion
85
Stages of inflammation (5)
Inflammatory cells release histamine, bradykinin, prostaglandins, etc. (pain) Increase in blood flow (erythema, heat) Increased permeability, leakage of plasma into ISF including protein (edema) Infiltration by leukocytes Ingrowth of fibrous tissue and healing
86
2 basic anti inflammatory effects of cortisol
1- block early stages of inflammation (prevention of inflammation) 2- Causes rapid resolution of inflammation to allow healing
87
Inflammation prevention... - stabilizes _________ - decreases ______ - decreases________ - suppresses___________ - Lowers ______
``` Stabilizes lysosomal membranes Decreases capillary permeability Decreases migration of leukocytes Suppresses the immune system Lowers fever ```
88
What are the two ways of resolving inflammation?
Blocks inflammatory mediators | Speeds healing by mobilization of aa for tissue repair and increasing glucose and FA
89
_______ are given therapeutically to reduce inflammation
Glucocorticoids
90
T or F: glucocorticoids fixes the underlying problem of inflammation
False; glucocorticoids DOESNT fix the underlying problem of inflammation just reduces it therapeutically
91
Most metabolic effects of steroid hormones require ______ minutes for proteins to be synthesized and ________ for full effect
45-60 min Hours-days
92
________ from the AP (anteiror pituitary) stimulates cortisol secretion
ACTH (corticotropin)
93
What mechanism is used to stimulate cortisol release via ACTH?
Adenylyl cyclase/ cAMP
94
_________ leads to the activation of ________ which converts cholesterol to pregnenolone
PKA; desmolase
95
______ is inturn controlled by corticotropin releasing factor (CRH) from the hypothalamus
ACTH
96
Cortisol excess exerts negative feedback on what glands?
Pituitary gland and hypothalamus
97
_______ inhibits the hypothalamus and anterior pituitary
Cortisol
98
Pain from physical damage is transmitted to the ________ ***stress source
Median eminence
99
Mental stress from the __________ is transmitted to the _________
Limbic system; posterior medial hypothalamus
100
_________ is the precursor to ACTH
Pro-opiomelanocortin (POMC)
101
POMC also produces what hormones other than ACTH?
Melanocytes stimulating hormone (MSH) Lipotropin Endorphin
102
Cortisol stabilizes: | This decreases:
Lysosomal membranes Decreases release of pro-inflammatory enzymes
103
Cortisol decreases:
Capillary permeability Migration of leukocytes
104
How does cortisol decrease migration of leukocytes?
By blocking inflammatory mediators
105
Cortisol suppresses what system
The immune system (especially T cells)
106
How does cortisol lower fever?
By decreasing IL-1 production
107
Cortisol inactivates or removes:
Inflammatory products
108
Cortisol speeds healing by:
Mobilization of amino acids for tissue repair Increasing glucose and fatty acid availability for critical systems
109
Glucocorticoids are given therapeutically to:
Reduce inflammation
110
DHEA and androstenedione are continually secreted by ________, especially during:
Zona Reticularis Fetal development
111
Much of pubic and axillary hair in remains is due to
Adrenal adrogens
112
Small amounts of ____ and _____ are secreted from the adrenals
Estrogens Progesterone
113
Most abundant steroid hormone
DHEA
114
DHEA causes cells to make
Testosterone and estradiol
115
DHEA levels decline with:
Age, stress and disease Lower levels associate with increased disease and increased mortality
116
DHEA’s association with cortisol
It balances and counteracts cortisol’s effects
117
DHEA reduces
Pain and inflammation
118
DHEA improves:
Immune system function, And, in women, fertility and sexual function
119
Addison’s disease, AKA:
Hypoadrenalism
120
Primary hypoadrenalism
Autoimmunity causes atrophy of the adrenal glands Destruction of tumor or tuberculosis
121
Secondary hypoadrenalism
Impaired pituitary and decreased release of ACTH
122
Symptoms of Addison’s disease
Bronze pigmentation of skin Hypoglycemia Changes in distribution of body hair Postural hypotension GI disturbances Weight loss Weakness
123
Adrenal crisis in Addison’s disease
Profund fatigue Dehydration Vascular collapse (decreased BP) Renal shut down Decreased serum NA Increased serum K
124
Mineralocorticoid deficiency : | Decreased:
ECF volume, hypotension Cardiac output- shock and death
125
______ and ______ are continually secreted by the zona reticularis especially during fetal development
DHEA and androstenedione
126
Testosterone and estradiol are synthesized from _____
DHEA
127
Levels of DHEA _____ with age, stress, and disease
Decline
128
______ balances and counteracts cortisol effects
DHEA
129
_______ reduces pain and inflammation, improves immune system functions and improves fertility and sexual function
DHEA
130
What is the disease associated with hypoadrenalism?
Addison’s disease
131
What is the disease associated with hyperadrenalism?
Cushing syndrome
132
What is primary Addison’s disease? (Hypoadrenalism)
Autoimmunity causes atrophy of the adrenal glands | Destruction by tumor or tuberculosis
133
Symptoms of Mineralocorticoid deficiency
Hyponatremia Hyperkalemia Acidosis
134
Review slide 49 for glucocorticoid deficiency
Review slide 49
135
In primary hypoadrenalism, _______ levels are high, causing MSH to be hyper-secreted
ACTH
136
Hyperadrenalism, AKA
Cushing’s syndrome
137
Causes of Cushing’s syndrome
Adenoma of the ant. Pituitary- secretes too much ACTH (most common) Hypothalamus produces too much CRH (Rare) Tumor elsewhere in the body secretes ACTH Adenoma of the adrenal cortex- secretes too much cortisol Prolonged glucocorticoid therapy
138
Symptoms of Cushing’s syndrome
“Buffalo torso” and “moon face” Acne and excess facial hair Hyperglycemia (adrenal diabetes) Severe weakness from protein depletion in the muscles Osteoporosis (lack of collagen) Purple stria (tearing of subcutaneous tissue)
139
What causes buffalo torso and moon face in cushing’s syndrome?
Mobilization of fat from the extremities to the trunk and edema
140
Primary aldosteronism, AKA
Conn’s syndrome
141
Causes of conn’s syndrome
Tumor of zona glomerulosa Hypersecretion of aldosterone
142
Features of Conn’s syndrome (6)
Hypokalemia Metabolic Alkalosis Slight increase in ECF and blood volume Hypertension Periodic muscle paralysis from hypokalemia Decreased renin production
143
Conn’s syndrome should be considered in any hypertensive pt with:
Muscle weakness, polydipsia, and/or hypokalemia
144
Causes of Conn’s syndrome
75%- Adrenal adenoma 25%- Adrenal hyperplasia Rarely- Adrenocortical cancer
145
Adrenal medulla is usually studied along with the:
Autonomic nervous system
146
Catecholamines synthesis occurs where? From what?
In the cytoplasm of chromatin cells From tyrosine
147
Stimulation of release of catecholamines
Direct sympathetic innervation
148
Alpha 1,2 receptors are used for: (6)
``` Vasoconstriction Iris dilation Intestinal relaxation Bronchoconstriction Increased heart contractility Hepatic glucose production ```
149
Beta 1,2 receptors stimulate (7)
``` Vasodilation Increased heart rate Increased heart contractility Intestinal relaxation Bronchodilator Glycogenolysis Lipolysis ```
150
Steps of short term stress response
1- hypothalamus sends nerve signals via spinal cord 2- nerve signals are sent to adrenal medulla 3- epinephrine and norepinephrine are secreted
151
Long term stress response steps
1- Hypothalamus stimulates anterior pituitary with releasing hormone 2- anterior pituitary releases ACTH into blood 3- ACTH sent to the adrenal cortex 4- Corticosteroids are released into bloodstream
152
Review slide 57
Review slide 57
153
Pheochromocytoma, AKA:
Catecholamine- secreting adrenal tumor
154
Epidemiology of Pheochromocytoma
Adults- both sexes, all ages (especially 30-50 years)
155
Biological behavior of Pheochromocytoma
90% benign, 10% malignant
156
Pheochromocytoma secretes high levels of ________, most secrete ________
High levels of catecholamines, most secrete norepinephrine.
157
Clinical presentation of Pheochromocytoma
Episodic or sustained hypertension, sweating, palpitations, hyperglycemia, glycosuria
158
Macroscopic features of Pheochromocytoma
Mass, often hemorrhagic; 10% bilateral; 10% extra-adrenal
159
Microscopic features of Pheochromocytoma
Nests of large cells, vascular stroma
160
Excess inflammation can cause
Can prevent or slow healing
161
Most metabolic effects of cortisol require ______ (time) for proteins to be synthesized, and (time) for full effect
45-60 min Hours-days
162
For steroid hormone metabolism: The hormone enters the ______, and attaches to the _____ _____. This creates a _____ _____ ____.
Cytoplasm Steroid receptor Hormone-receptor complex
163
For steroid hormone synthesis: | After binding to the steroid receptor in the cytoplasm, what happens to the hormone-receptor complex?
It enters the nucleus Here it binds to receptor sites on chromatid, activating mRNA transcription
164
ACTH aka:
Corticotropin
165
ACTH comes from the: It stimulates :
Anterior pituitary | Cortisol secretion
166
How does ACTH stimulate cortisol secretion
Adenylyl Cyclase/cAMP mechanism Protein kinase A leads to activation of desmolase, which converts cholesterol to prefnenolone
167
ACTH is controlled by ______ which is secreted by the ______
Corticotropin releasing factor Hypothalamus
168
Review slide 44
Review slide 44
169
Cortisol inhibits the:
Hypothalamus and anterior pituitary
170
Cortisol stimulates (4)
Gluconeogenesis Protein mobilization Fat mobilization Stabilizes lysosomes
171
Stress sources for pain: Mental stress:
Pain- from physical damage - transmitted to the median eminence Mental stress- From the lambic system - transmitted to the posterior medial hypothalamus
172
Precursor to ACTH
Pro-opiomelanocortin (POMC)
173
Breakdown of POMC also produces
Melanocyte stimulating hormone Lipotropin Endorphin And a few others
174
When ACTH rate is high, this means that:
Other POMC products may also be overproduced
175
What type of gland is the pancreas
Both endocrine and exocrine
176
Pancreatic acini is (ENDOCRINE/EXOCRINE) | Secretes:
Exocrine Digestive juices
177
Islets of Langerhans is (ENDOCRINE/EXOCRINE) Cells inside them
Endocrine Alpha cells Beta Cells Delta Cells
178
Alpha cells in the pancreas (islets) release
Glucagon
179
Beta cells in the pancreas (islets) release:
Insulin, amylin
180
Delta cells in the pancreas (Islets) releases
Somatostatin
181
Insulin is associated with:
Energy abundance
182
Insulin is secreted when?
When energy rich foods are eaten (especially carbohydrates) Stimulated by high blood glucose
183
Insulin promotes:
Storage of excess energy
184
Insulin effects in the liver
Glucose -> Glycogen
185
Insulin effects in adipocytes
Fatty acids -> TAGs
186
Insulin effects of other cells
Amino acids -> protein
187
After translation, insulin is initially
Preproinsulin
188
Preproinsulling is cleaved in the ______, to form:
ER | Proinsulin
189
Proinsulin is cleaved in the _______ into:
Golgi | Insulin and “C pepetide”
190
What happens to insulin once cleaved?
It is packaged into secretory vesicles When released, it circulates unbound
191
Half life of insulin
Approx 6 min
192
C peptide binds to a ____ _____ and activates
Membrane receptor Some enzymes
193
How is c-peptide used clinically?
Used as a measurement in insulin-treated patients Can be assessed for any endogenous insulin production
194
C peptide is useful for
Monitoring beta cell function in people with diabetes who are on insulin therapy
195
Insulin receptor has ___ subunits
4
196
What type of receptor is an insulin receptor
Enzyme-linked
197
Autophosphorylation of the insulin receptor activates:
Tyrosine kinase
198
Tyrosine kinase activates
Tissue specific IRS (insulin receptor substrate) enzymes
199
Insulin receptor substrates:
``` Growth and gene expression Glycogen synthesis Fat synthesis Protein synthesis Glucose transport ```
200
____% of body cells increase glucose uptake
80
201
Glucose uptake- most profound effect is in:
Muscle and fat
202
Most brain cells are _____ independent
Insulin
203
Mechanism of glucose uptake
Fusion of vesicles containing glucose (GLUT4) | Transport proteins to the cell membrane
204
GLUT1 is responsible for:
Baseline uptake ***Ubiquitous and present in many cells
205
GLUT2 is found where?
Liver Kidney Pancreatic Beta cells Intestine THIS IS BI-DIRECTIONAL
206
GLUT3 found in:
Neuron Placenta Has high affinity
207
GLUT 4 found in It is ______ dependant
All muscles Adipocytes Heart Insulin dependant
208
Muscle mostly depends on _____ ______ between meals
Fatty acids
209
Circumstances when muscle uses more glucose
Exercise- Increases permeability to glucose After a meal- Insulin increases glucose uptake, then stored as glycogen if not needed
210
Mechanism of storing glucose as glycogen in the liver
Insulin inactivates glycogen phosphorylase Stimulates glucokinase Stimulates glycogen synthase
211
What happens to excess glucose after glycogen is maximized
It is converted to fatty acids (VLDL)
212
What happens in the liver when there is lack of insulin
Reverse effects on phosphorylase, glucokinase and glycogen synthase Glycogen is broken down
213
What is activated to release glucose into the blood? Why?
Glucose phosphates Insulin is low.
214
Most brain cells are permeable to _____ and do not need ____
Glucose Insulin
215
Brain normally only uses glucose for _______, therefore depends on:
Energy Blood glucose
216
When blood glucose falls to low in the brain, what happens?
Hypoglycemic shock occurs (fainting, seizures and coma)
217
Insulin in adipose promotes:
Fatty acid synthesis by liver that is then transported to fat cells (VLDL) Also glucose transport into fat cells, mostly to form glycerol
218
Insulin in adipose inhibits
Hormone-sensitive lipase (HSL), thereby inhibiting release of fat from adipocytes
219
For protein metabolism, insulin promotes: It prevents:
Promotes protein formation Prevents protein degradation
220
For protein metabolism, insulin stimulates: It inhibits:
Amino acid uptake by cells Protein catabolism
221
For protein metabolism, insulin increases: It decreases:
mRNA translation into new protein And Gene expression for enzymes needed for carb, fat, and protein storage Decreases: Liver gluconeogenesis (amino acids are NOT converted to sugar)
222
What causes weight gain the most?
Growth hormone AND insulin together
223
When insulin is deficient, what happens to hormone sensitive lipase
It becomes active, releases large amounts of fatty acids and glycerol into the blood
224
When insulin is deficient, what happens to glucose concentrations?
They rise
225
When insulin is deficient, what happens to plasma cholesterol and phospholipids?
They rise- accelerating atherosclerosis
226
Excessive beta oxidation of fats in the liver creates:
Excess acetyl-CoA, which is then converted to Acetoacetic acid
227
What happens to excess acetoacetic acid that cannot be metabolized back to acetyl-CoA in other tissues
It forms ketone bodies (Beta-hydroxybutyric acid and acetone)
228
Ketoacidosis may lead to:
Coma and death
229
Acetoacetate is created from: It is converted into:
Breakdown of fatty acids Into BHB or turned into acetone
230
Beta-hydroxybutyric acid formed from: Why is this not technically a ketone?
Acetoacetate Because of its structure- we consider it as one within the keto diet
231
Acetone is created as: It breaks down: How is it removed?
As a side product of acetoacetate Quickly From the body through the waste or the breath
232
Norepinephrine ->normetanephrine via what enzyme? Epinephrine-> metanerphine via what enzyme
COMT (catechol-O-methyltransferse) COMT
232
Epinephrine and norepinephrine are converted to dihydroxymanfdelic acid via what enzyme?
MAO ( monoamine oxidase)
233
What happens when there is a protein depletion and increased plasma amino acids?
Catabolism of proteins increase Large amounts of amino acids are released into the plasma Some amino acids are used for gluconeogenesis (also glycerol and lactic acid)
234
Glucose enters/leaves the pancreatic beta cell via the
GLUT 2 channel
235
What happens with pancreatic beta cell when blood glucose is high
More glucose enters the cell, stimulating ATP synthesis
236
ATP closes the ____ channel, causing
K+ Depolarization
237
What happens when K+ channel closes in pancreatic beta cell
V-gated Ca+2 channel opens and Ca+2 triggers exocytosis of insulin
238
What inhibits exocytosis of insulin in the pancreatic beta cell
Somatostatin and NE
239
normal fasting blood glucose level:
80-90 mg/100 ml
240
What happens immediately after acute elevation of blood glucose? (After meal)
10x increase in insulin
241
What happens w insulin about 15 min after meal?
Increase due to new insulin synthesis (there is a dip between the 1st and second phase)
242
Most potent amino acids
Arginine and lysine
243
There is a higher response with arginine and lysine than _____ alone, when they are all combined together
Glucose
244
Gastrointestinal hormones that control insulin secretion
Gastric, secretin, cholecytokinin, glucose-dependent insulinotrophic peptide (AKA gastric inhibitory peptide)
245
Gastrointestinal hormones cause:
An “anticipatory” increase in blood insulin
246
Other hormones that control insulin secretion
Glucagon Growth hormone Cortisol
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Factors that increase insulin secretion:
``` Increased blood glucose Increased blood FFA Increased blood amino acids Gastrointestinal hormones (gastric, CCK, secretin, GIP) Glucagon, growth hormone, cortisol Parasympathetic stimulation (Ach) Insulin resistance, obesity ```
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Factors that decrease insulin secretion
``` Deceased blood glucose Fasting Somatostatin Alpha-adrenergic activity (NE) Leptin ```
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Type 1 diabetes mellitus
Insulin dependent (IDDM) Lack of insulin secretion by pancreas Autoimmune disease against beta cells, viral infections, genetics— there are factors
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Type II diabetes mellitus
Non-insulin dependent (NIDDM) | Decreased sensitivity to insulin (insulin resistance)
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Signs and symptoms of type 1 diabetes
``` Increased blood glucose Glucose readings Polyurea Dehydration Polydipsia Polyphagia with weight loss Blood vessel damage Peripheral neuropathy Hypertension/kidney disease Atherosclerosis Ketoacidosis (metabolic acidosis) ```
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Which type of diabetes is more common
Type II- 90-95% more common
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Type II diabetes usually occurs: It is often associated with:
After age 30, gradual onset Obesity
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Type II insulin levels: Also comes with:
Increased Mild hyperglycemia Beta cell exhaustion Less problems with ketoacidosis than type 1
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Diabetes complications: | Macrovascular:
``` Stroke Heart disease and hypertension Peripheral vascular disease Foot problems Unstable plaque ruptures ```
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Microvascular diabetes complications
``` Diabetic eye disease (retinopathy and cataracts) Renal disease Neuropathy Foot problems Blood clot blocks blood flow ```
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Hyperinsulin
Too much insulin
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Causes of too much insulin
Adenoma of islets of langerhans (rare) Insulin “shock”
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Insulin shock- Insulin causes: Nervous system ____
Excessive drop in plasma glucose Starves
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Insulin shock initially leads to: Then hypoglycemia progresses to:
Hallucinations, tremors, nervousness Seizures, coma
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What causes insulin shock?
Too much insulin in the blood due to overdose during an insulin shock
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Too much insulin results in:
Too little blood glucose
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What will counteract insulin shock
Immediate intake of sugar
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Structure of glucagon
Large polypeptide
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Glucagon is secreted by
Alpha cells of the islets
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Effects of glucagon:
``` Increase glycogenolysis (liver) Increased gluconeogenesis (liver) ``` Activated adipose cell lipase
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How does glucagon stimulate glycogenolysis
Uses adenyl cyclase/cAMP/Protein Kinase A mechanism PKA activates phosphorylase b kinase into phosphorylase a kinase Degradation of glycogen into glucose-1-phosphate is promoted This is then dephosphorylated and glucose is released from liver cells These steps exhibit “amplification”
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Gluconeogenesis increases:
Rate of amino acid uptake by liver cells
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Gluconeogenesis includes conversion of:
Some amino acids into glucose by activating enzymes repsponsible
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at high levels, glucagon activates:
Adipose cell lipase making fatty acids available to the body
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What stimulates glucagon secretion
Hypoglycemia Autonomic activation Increased plasma amino acids (aa would increase insulin production, however in the case of glucagon, the amino acids are used for gluconeogenesis)
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Inhibition of glucagon secretion
Hyperglycemia Insulin Somatostatin
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Structure of somatostatin
Polypeptide
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Somatostatin is secreted by
Delta cells
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Effects of somatostatin
Depresses insulin and glucagon secretion Decreases stomach motility, GI absorption Extends time over which food is assimilated into tissues
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Somatostatin is AKA as
The growth hormone inhibitory hormone from the hypothalamus
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Stimulation of somatostatin increases:
``` Plasma glucose, amino acid, and FA levels GI hormones (gastric, secretin, cholecytokinin, GIP) ```
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Inhibition of somatostatin
Decreased plasma glucose, amino acid, FA levels
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What are the two enzymes involved in catecholamines degradation?
MAO | COMT
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Insulin and glucagon levels for glycogen synthesis
Insulin increases | Glucagon decreases
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Insulin and glucagon levels for glycolysis (energy release)
Insulin increases Glucagon decreases
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Insulin and glucagon levels for lipogenesis
Insulin increases Glucagon decreases
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Insulin and glucagon levels for protein synthesis
Insulin increases Glucagon decreases
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Insulin and glucagon levels for glycogenolysis
Insulin decreases Glucagon increases
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Insulin and glucagon levels for gluconeogenesis
Insulin decreases Glucagon increases
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Insulin and glucagon levels for lypolysis
Insulin decreases Glucagon increases
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Insulin and glucagon levels for ketogenesis
Insulin decreases Glucagon increases
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Insulin’s effect on: Blood sugar: Cell sugar utilization: Cell fatty acid utilization: Protein synthesis: Speed of response:
Bs- decreases CSU- Increases CFU- decreases PS- increases SOR- Fast
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GH effects on: Blood sugar: Cell sugar utilization: Cell fatty acid utilization: Protein synthesis: Speed of response:
BS- increase CSU- decrease CFU- increase PS- Increase SOR- slow
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Glucagon effect on: Blood sugar: Cell sugar utilization: Cell fatty acid utilization: Protein synthesis: Speed of response:
BS- increase - with gluconeogenesis CSU- decrease CFU- increase PS- decrease SOR- fast
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Epinephrine effect on: Blood sugar: Cell sugar utilization: Cell fatty acid utilization: Protein synthesis: Speed of response:
Bs- increase CSU- increase CFU- increase PS- N/A SOR- fast
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Cortisol effects on Blood sugar: Cell sugar utilization: Cell fatty acid utilization: Protein synthesis: Speed of response:
BS- Increase CSU- decrease CFU- increase PS- decrease (except liver) SOR- slow
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Blood Ca+2 and PO4 concentrations depend on: (3)
Intestinal absorption rate Renal excretion rate Bone mineral uptake/release
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Major regulatory factors of Ca+2 and PO4
Parathyroid hormone Calcitonin Vitamin D
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Ca+2 secreting organs
Bone Kidney Intestine
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Important Ca+2 functions
Muscle contraction Nerve impulse transmission Blood clotting factor Bone matrix component Neurotransmitter release
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ECF concentration must be:
Tightly controlled
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Signs of hypocalcemia
Nervous system hyper-excitability Poor blood clotting Numbness and tingling Tetany, spasms Cardiac arrhythmia
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Signs of hypercalcemia
Nervous system compression (depression, conduction, lethargy) Cardiac arrhythmia Constipation, nausea, vomiting
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Percentage for normal body calcium distribution for ECF/plasma Cells In bones
ECF- 0.1% Cells- 1% Bones- 99%
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Calcium distribution in plasma
50% ionized calcium 41% protein-bound calcium 9% Ca+2 complexed to anions
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Phosphate distribution in body
85% in bones 14-15% in cells < 1% in ECF
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Depending on _____, phosphate forms:
PH HPO4^-2 H2PO4^-1
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Functions of phosphates
Bone matrix Intracellular buffer Renal tubular buffer Phosphorylation (ATP, Enzymes, Etc)
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Hyper/Hypo phosphatemia
Not generally significant except phosphate depletion may lead to bone demineralization
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Review picture in slide 102
Slide 102
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Osteoid in bones give: Includes:
Tensile strength Collagen fibers Ground substance
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Bone salts give: | Includes:
Compressive strength Hydroxyapatite crystals Ca10(PO4)6(OH)2 Non crystalline amorphous substances - CaHPO4.2H2O - Ca3(PO4)2.3H2O
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What inhibits HAP deposition in tissues other than bone?
Pyrophasphate
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Calcification of osteoblasts process
Osteoid is laid down Osteoblasts become encased and become osteocytes Precipitation of bone salts in osteoid Woven bone (new bone) becomes low HAP, high amorphous salts Replaced by stronger bones (higher HAP) Some amorphous salts are always there and easily exchanged
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Formation of osteocyte
Osteogenic cells To osteoblasts To osteocytes
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Osteoclasts secrete
Proteolytic enzymes and acid, which tunnels into bone - osteoblasts fill in the new bone
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Calcification and absorption =
Remodeling
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Review slide 106 for Vitamin D
Slide 106
315
Active form of vitamin D
1/25 dihydroxycholecalciferol
316
Vitamin D promotes
Intestinal calcium absorption (Calcium binding protein) Phosphate absorption by intestines
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Vitamin D decreases
Renal calcium and phosphate excretion (minor)
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Excessive vitamin D leads to
Bone absorption
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Small amounts of vitamin D leads to
Bone calcification
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Parathyroid hormone (PTH) without vitamin D leads to
No absorption
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Anatomy of parathyroid gland
4 small glands located post to the thyroid gland 2 on the left 2 on the right
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Parathyroid gland- Chief cells secrete: Oxyphil cells:
PTH Function of oxyphil cells is unknown
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PTH target tissues
Bone- cAMP dependant Kidneys- cAMP dependant Intestines- indirectly due to PTH effects on vitamin D
324
PTH increases: | How?
Blood CA+2 levels | Mainly by bone absorption
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PTH decreases: How?
Blood phosphate levels Mainly by increase excretion by kidneys
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What inhibits PTH release
Rising Ca+2 in blood | Calcitonin, Vitamin D
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PTH activates:
Osteoclasts- calcium and phosphate ions release in the blood as a result.
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Specific effect PTH has on intestines
Increases the calcium and phosphate absorption from food (bc of increased vitamin D)
329
How does PTH affect the kidneys
Promotes activation of vitamin D Decreases calcium excretion Increases phosphate excretion (which overrides increased phosphate absorption from bone) Occurs mainly in the distal tubules collect tubules
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2 phases of bone absorption by PTH:
Rapid phase (osteolysis) Slow phase
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Rapid phase of bone absorption is mediated by: It causes:
Osteocytes and osteoblasts (have PTH receptors) Causes release of calcium and phosphorus salts
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Slow phase of absorption is mediated by: It breaks down:
Osteoclasts activated indirectly by osteocytes and osteoblasts. This stimulate osteoclasts and increase development of new osteoclasts Breaks down osteoid as well as minerals
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PTH is stimulated by:
Decreased ECF Ca+2, histamine, epinephrine
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PTH is released in a ______ pattern
Diurnal
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What happens with hypoparathyroidism
Calcium reabsorption from bones is depressed
336
What happens to ECF Ca+2 levels with hypoparathyroidism
It decreases (hypocalcemia)
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Hypoparathyroidism results in
Tentany
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Signs of hypoparathyroid
Muscle spasm of hands and feet
339
Potential causes of hypoparathyroidism
Autoimmune disorder Thyroid surgery complication Genetic
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Peptide released by parafollicular cells of the thyroid gland
Calcitonin
341
Calcitonin target tissue
Bone
342
Effects of calcitonin
Decrease in: Osteoclasts activity Osteocytic osteolysis Formation of new osteoclasts
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Prolonged decrease in osteoclasts activity leads to: Therefore:
Decreased osteoblast activity No appreciable changes in calcium ion concentration —there is a very weak effect on kidney to increase calcium excretion
344
Hyperparathyroidism causes extreme:
Osteoclastic activity
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Hyperparathyroidism increases:
ECF Ca+2 levels (hypercalcemia)
346
Hyperparathyroidism causes decreased:
Phosphate levels
347
Hyperparathyroidism and its effect on bones
It weakens bones with frequent fractures Cystic bone “osteitis fibrosa cystica”
348
Hyperparathyroidism causes high:
Plasma alkaline phosphate seems
349
Hyperparathyroidism causes depression of:
Nervous system, muscle weakness and constipation
350
Hyperparathyroidism causes metastic:
Calcification And kidney stones
351
Primary causes of Hyperparathyroidism
Tumor Autoimmune disease
352
Secondary causes of Hyperparathyroidism
Vitamin D deficiency\
353
Vitamin D deficiency leads to
Hypocalcemia and hypersecretion of PTH (Rickets- child) (Osteomalacia- adult)
354
Types of physiological alkaline phosphatase (ALP)
Infancy Puberty Pregnancy Intestinal isoenzymes
355
Bone diseases that cause increase serum alkaline phosphatase enzyme activity
Hyperparathyroidism Osteomalacia, rickets Paget’s disease of bone Osteomyelitis
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Hepatobiliary diseases that cause increase serum alkaline phosphatase enzyme activity
Hepatitis Cholestasis Cirrhosis
357
Another cause of alkaline phosphatase
Carcinoma of the bronchus
358
Effects of rickets
Short stature (stunted growth) Odd-shaped skull Spine deformities Pigeon chest Odd-shaped ribs Pelvic Deformities Wide wrist joints Wide knee joints Bowlegs Wide ankle joints