week 3 Flashcards
(267 cards)
1
Q
What are the two metabolic states? (in term of food consumption)
A
Fed state: just after meal, anabolic, use glucose as energy
Fasted state: hungry, catabolic, breakdown glucose/ fat for energy
2
Q
What is basal metabolic rate?
A
BMR= most basic metabolism required,
Energy expenditure when resting, to maintain most basic functions (temperature, etc)
3
Q
What happen to glucose in fed state?
A
Glycogenesis, storing glucose into glycogen
4
Q
What happen to glucose in fasted state
A
Glycogenolysis, glycogen breakdown into fee glucose
5
Q
How does glucose provide ATP?
A
Glycolysis, TCA and oxidative phosphorylation
6
Q
What happen to fatty acid/ glycerol during fed state
A
Lipogenesis, storing fat as triglycerides (adipose tissue)
7
Q
What happen to fatty acid/ glycerol during fasted state
A
Lipolysis, breakdown adipose tissue into fatty acid
8
Q
How does fatty acid provide ATP
A
Beta oxidation of free fatty acid
9
Q
What happen to amino acid during fed state
A
Protein synthesis, build muscle
10
Q
What happen to amino acid during fasted state
A
Protein degradation, breakdown muscle into amino acid
11
Q
What is gluconeogensis, and when does it happen
A
Glucose synthesis from non-carbohydrates molecules, such as glycerol/ amino acid
Happen during fasted state
12
Q
What do exocrine pancreas cells do?
A
Produce bicarbonate/ proenzyme for digestion
13
Q
What does endocrine pancreas do? (general)
A
secrete hormone to bloodstream
14
Q
What does Beta cell secrete?
A
Secrete proinsulin, that will be cleaved into insulin
15
Q
What does alpha cell secrete
A
Secrete glucagon
16
Q
What does sigma cell secrete
A
Somatostatin
17
Q
What does insulin bind to
A
Single transmembrane receptor, receptor tyrosine kinase
18
Q
What does glucagon bind to
A
7-transmembrane G-protein coupled receptor
19
Q
how does insulin and glucagon trigger different signalling cascade
A
They share the same target cell, but bind to different receptor, so different signalling cascade is initiated
20
Q
What does insulin and glucagon regulate?
A
Signal target cells to change gear between fed and fasted state, controlling the glucose homeostasis
21
Q
What is the level of insulin/ glucagon in fasted VS fed state
A
Insulin: high in fed state, low in fasted state
Glucagon: high in fasted state, low in fed state
22
Q
What is the relationship between blood glucose and insulin
A
Insulin push glucose inside cell, decreasing blood glucose level
Low plasma glucose, low insulin level
23
Q
When is insulin dominate
A
During fed state, anabolic, high blood sugar
24
Q
What is insulin synthesized from
A
Peptide, made in advance and stored in vesicles
25
What enzyme does insulin activate
Enzyme involved in glycogenesis, lipogenesis, protein synthesis, activating the anabolic reaction
26
What is the mechanism of insulin action
1: Fed state, insulin bind to tyrosine receptor kinase
2: Receptor kinase phosphorylate IRS (insulin receptor substrate)
3: IRS stimulate secondary messenger pathway
4: Secondary messenger pathway alter protein synthesis and existing protein
5: More glucose transporter, promote glucose influx
Alter enzyme, modify cell metabolism
26
What enzyme does insulin inhibit
Catabolic enzyme, for glycogenolysis, gluconeogensis, lipolysis
27
Where is GLUT4 found?
Muscle/ adipose tissue
28
What is glut 4 mechanism? (in term of movement in cell, when there's low VS high plasma glucose)
Low glucose: insulin receptor is not bound, GLUT 4 stay in secretory vesicles inside cell cytoplasm
High glucose: Insulin binding receptor trigger signalling cascade, GLUT4 gets exocytosed to cell membrane, moving glucose inside cell
29
Where is glut 2 found?
Liver
30
What is the role of hexokinase (in liver)
Hexokinase is activated by insulin, and it converts glucose inside liver cell to G6P
This keep a low intracellular glucose concentration, so glucose gradient is maintained, and more glucose can moved inside cell through GLUT 2
31
What is the mechanism of insulin release?
1: increase glucose level in blood
2: Glucose enter beta cell, promote glycolysis, citric acid cycle, increasing ATP in cell
3: ATP bind to ATP sensitive potassium channel, closing the channel
4: Increase intracellular potassium level, causing depolarization (more positive)
5: Depolarization open Ca2+ channel and cause Ca2+ influx, which trigger insulin exocytosis secretion
32
What is incretin effect?
When glucose is intrajejunal infused ( intestinal), it causes a huge spike of insulin that is much higher than IV glucose injection
33
What is the cause of incretin effect?
When insulin is absorbed from intestine, intestine make gastrointestinal hormone that support insulin action, causing enhanced insulin response toward intrajejunal glucose
34
What are the two gastrointestinal hormones that support inuslin action
Gastric inhibitory peptide (GIP)
Glucagon-like peptide 1 (GLP1)
35
What is the stimulators and effect of GIP
Gastric inhibitory peptide:
stimulator: nutrients (glucose, fat, amino acid)
Effect: increase insulin, decrease gastric emptying/ acid
36
What is the stimulators and effect of GLP-1
Glucagon like peptide 1
Stimulator: nutrients. parasympathetic activity
Effect: Increase insulin, decrease glucagon, increase Beta cell growth, decrease gastric acid/ emptying
37
What type of regulation is GLP1/ GIP on insulin
Feed forward regulation, promote increase of insulin activity
38
What does sympathetic nervous syetm do to insulin secretion
Sympathetic nervous system: inhibitory, fight or flight response decrease insulin release, so more glucose can be available in blood
39
What is parasympathetic nervous system and what does it do to insulin level
Rest and digest phase, which trigger insulin release
40
What does glucagon target
Liver
41
What does glucagon trigger?
Glycogenolysis, gluconeogenesis, ketogensis
42
When does glucagon dominate
DUring fasted state
43
What does glucagon prevent? (main goal)
Prevent hypoglycemia
44
What is glucagon made from
Large peptide hormone
45
What is the mechanism of glucagon
1:When fasting, glucagon bind and activate Gs protein in hepatocytes
2:Gs activate adenyl cyclase, produce cAMP
3: cAMP activate PKA, activate phosphorylase b kinase
4: phosphorylase b kinase convert phosphorylase b to phosphorylase a
5: phosphorylase a convert glycogen to G-1-P then to glucose
6: High level of intracellular glucose move out the hepatocytes into the blood stream, through GLUT2
46
What is needed by glucagon, in order to allow full activity of glucagon and epinephrine
Cortisol, due to permissive effect
47
What inhibit glucagon release
GLP-1
48
What does increase amino acid do to glucagon secretion
It stimulate glucagon release ( also stimulate insulin release)
49
Why is both insulin and glucagon released, when someone is taking a protein only diet
Amino acid stimulate release of insulin, which promote glucose influx and storage, decreasing blood glucose
Since plasma glucose is already low, hypoglycemia might occur
Glucagon is therefore release to counter this
50
What does sympathetic nervous system do to the glucagon secretion
It stimulate glucagon release, so more blood glucose available for fight/ flight
51
What does proglucaon contain, and how is it regulated?
It contains glucaon, GLP-1 and GLP2
Glucagon is expressed in alpha cell
GLP-1 and GLP-2 is expressed in L cells of intestine and brain
The expression is regulated by cleaving
52
What is type 1 diabetes? What is the cause and treatment
Insulin dependant, occur in younger age die to genetics
Cause by insulin secretion decrease/ absent
treat by insulin injections
53
What is type 2 diabetes? What is the cause and treatment
Non-insulin dependent, mature onset, most common diabetes
Defect in insulin secretion and target cell sensitivity to insulin
Treat by diet, exercise, oral hypoglycemics, sometimes insulin injection
54
What is the consequence of diabetes?
High blood glucose if uncontrolled
55
How does sulfonylureas treat diabete
Treat type 2 diabetes
It closes the ATP sensitive potassium channel, forcing depolarization and Ca2+ influx, increasing insulin secretion
56
How does GLP-1 agonist drug treat diabetes?
It increases insulin secretion and insulin sensitivty, and decrease appetite and gastric emptying
57
What are the consequences of uncontrolled type1 diabete
1: No glut 4, no glucose influx, hyperglycemia
2: High blood sugar gets filtered in kidney, urinate a lot of sugar, which pull water out, cause low blood volume and pressure
3:Water in blood decrease, sodium remain the same, cause high osmolarity
4: Can't use insulin as fuel, so used fat and protein instead, causing lost of body tissue
5: Liver increase ketonegenesis, glycogenolysis, gluconeogensis, further cause hyperglycemia
6: Ketone production is acidic, drive body pH away from homeostasis
58
What are the two hormone "secrete" by posterior pituitary
Vasopressin (ADH) and oxytocin, produced by hypothalamus
59
Where does oxytocin act on
mammary gland and uterus
60
How does anterior release its hormones
1: Hypothalamus synthesize trophic neurohormone and release them into portal system
2: Portal vein carry the neurohormone to the anterior pituitary, stimulate for downstream hormone release
3: Endocrine cells of anterior pituitary release their peptide hormone into blood stream, and distribute to the rest of the body
61
What regulation are all the hypothalamus-pituitary pathway under
Negative feedback control
62
What does RH stand for? where is it found?
"releasing hormone", made by hypothalamus
63
What does SH stand for? where is it found?
Stimulating hormone, made by anterior pituitary
64
Is bone mass always increasing?
No, it will start decreasing after certain age
65
When does bone mass peak?
early adulthood
66
When does the most growth in bone mass occur?
During childhood and teenage
67
What is a cause of bone loss in female?
Menopause, due to change in sex hormone
68
What is epiphyseal growth plate
The soft bone cartilage portion that is not ossified, so it can be grown into mature bone
69
What is needed for bone ossification
Osteoblast
70
Why does adult stop bone growing?
All the bones are fully ossified, so the growth plate is closed, no more growth is possible
71
What is chondrocytes?
Cells of cartilage
72
How does bone growth work? (why does it get longer)
Old chondrocyte disintegrate, and is replaced by osteoblast with bone. Osteoblast add bone on top of cartilage
Chondrocytes produce new cartilage, and the dividing chondrocyte widen the growth plate, making the bone longer
73
How does bone growth ceases?
All the cartilage is replaced by bone, and the epiphyseal plate (gap between bone) is fused by bone
74
What type of hormone is Growth hormone (GH)? in term of biochemisrty
Peptide hormone
75
Where is GH released from
anterior pituitary
76
What stimulate the release of GH
GHRH
77
What inhibit the release of GH
Somatostatin (GHIH)
78
What is the mechanism of GH? from hypothalamus to target
1: Circadian rhythm stimulate hypothalamus, releasing GHRH
2: GHRH stimulate GH release in anterior pituitary
3: GH act in liver, stimulate the release of insulin like growth factor (IGF)
4: IGF stimulate cartilage growth
79
How is GH release regulated? (regulatory pathway)
Negative feedback, when sufficient IGF is made, it inhibit GH and GHRH release
80
What is IGF-1?
Insulin-like growth factor 1, anabolic, promote growth in almost every cell in body
81
How is IGF-1 "insulin like"?
Similar structure
82
How does GH stimulate bone growth?
Increase IGF-1 release, which increase chondrocytes recruitment and proliferation, increasing cartilage matrix
83
How is GH catabolic?
In order for growth, sufficient energy must be needed
GH stimulate fat breakdown(energy), amino acid uptake (tissue building), enhance cellular proliferation and reduce apoptosis(cell division)
Stimulate glycolysis and gluconeogensis in liver (fuel)
84
What are 4 things that growth depend on
Diet, genetics, hormone and growth factor
85
What is gigantism?
Too much GH in childhood, causing bone length longer than normal (abnormally tall)
86
What is acromegaly?
Too much GH in adulthood
Won't be abnormally tall since growth plates are closed, but cause bone deposit "at the end", flatter/ irregular shape ( face and hands)
87
Where is thyroid gland located?
Back of the neck
88
How is thyroid hormone made? (hormone synthesis only)
1: In follicular cell, thyroglobulin is synthesized , which is the hormone precursor protein
2: Ionized iodine is moved into cell throughtNa+I- symporter, and is moved to colloid through pendrin
3: In colloid, Thyroid peroxidase add iodine to tyrosine on thyroglobulin, making T3 and T4
4: Modified thyrogloublin is moved back to follicle cells in vesicles
5: Intracellular enzyme cleave of T3 and T4 from thyroglobulin, and free T3 T4 enter circulation for its function
89
What are the thyroid hormone
T3 and T4
90
What is the backbone of thyroid hormone
Tyrosine
91
What us MIT
Monoiodotyrosine, contain tyrosine and one iodine
92
What is DIT
Diiodotyrosine, contain MIT and one iodine (2 iodine)
93
What is T3
Triiodotyrosine, contain one MIT one DIT (3 iodine)
94
What is T4
Thyroxine, contain 2 DIT (4 iodine)
95
Where is thyroid hormone made
THyroid follicle, which contain follicular cell surrounding the colloid (protein rich)
96
How is thyroid hormone released?
1: Tonic release, which is constant, stimulate the release of TRH from hypothalamus
2: TRH stimulate anterior pituitary, which release TSH
3: TSH stimulate T3 T4n release from thyroid gland
97
How is thyroid hormone release regulated
When sufficient thyroid hormone is made, it negative feedback inhibit TRH and TSH release
98
What type of hormone is TSH, in term of biochem
Peptide
99
What does TSH activate (receptor?)
G-protein linked membrane receptors on the thyroid gland, which stimulate the synthesis and activity of enzyme involved in T3T4 production
Also activate transcription factor, stimulating thyroid growth
100
What is the thyroid hormone physical property, and how does it move in the body
It is lipophilic/ hydrophobic, so it circulates in blood, bounding to plasma protein
101
Which thyroid hormone is more potent? Which convert to which in target tissue?
T3 is more potent that T4
T4 convert to T3 in target tissue
102
What does T3 and T4 do to cell?
Both translocate inside cell and bind to nuclear thyroid receptor, altering gene transcription
103
What doe T3 and T4 form hetero/homodimer with?
Retinoic acid receptor
104
What are the function of thyroid hormone? (metabolic, nervous system, growth and development, cardiovascular, muscular)
Metabolic: maintain/ regulate basal metabolic rate, influence metabolism of nutrients
Nervous: enhance speech, thinking, reflexes
Growth: works with GH, essential in children
Cardiovascular: enhance heart rate&contractility, peripheral blood flow, works in part by increasing number of beta-adrenergic receptors,)
Muscular: cause protein degradation and muscle weakness, if excess is presented
105
What is cause hyperthyroidism?
Tumours on thyroid gland, or thyroid stimulating immunoglobulins ( Grave's disease)
106
What are the symptoms of hyperthyroidism
Overall: hyperactivity of whole body due to abnormal excess metabolism
Goiter (enlargement of thyroid)
Nervousness
Insomnia
anxiety
high heart rate
exophthalmos (eye ball bugging out)
weight loss
107
What are treatment for hyperthyroidism
Remove part of thyroid gland
drugs that block T3/T4 synthesis, or T4-->T3 conversion
108
What is Grave's disease
Autoimmune disease, which abnormal antibodies IgG, against the TSH receptors are produced
Antibody bind to TSH receptor on thyroid gland, mimicing TSH, causing hyperactivity of thyroid gland, which cannot be negative feedback regulated
109
What is the cause of hypothyroidism
Under active thyroid gland
Lack of iodine in diet
110
What are the symptoms of hypothyroidism
General: decrease in metabolism, hypoactivity of body (slow down)
Goiter (thyroid try to make more hormone, constantly stimulated)
Slowed heart rate, speech
Fatigue
Cold-intolerance (thyroid hormone is essential for body temp)
cretinism in infants
Stunted growth in infants (T3T4 work with GH)
weight gain
111
How is hypothyroidism treated
Exogenous thyroid hormone T4 pill
112
What is the consequence of iodine deficiency
Thyroid cannot produce T3 or T4
Insufficient T3 T4 decrease the negative feedback loop, causing excess TSH production ( and TRH)
Excess TSH stimulate growth of thyroid gland, goiter is formed
113
Who produce gametes?
Both male and female, and their gametes fuse to produce new cell
114
How many chromosomes are found in gametes
23 chromosomes, it's haploid cell
115
What is meiosis VS mitosis
Meiosis: produce gametes
DNA replicate twice, and cell divide twice to form haploid cell (gametes)
Mitosis: normal cell division
DNA replicate once, and cell divide once
116
What control reproduction? (for male and female)
Both male and female have hypothalamic/ pituitary control of production
117
What is GnRH
gonadotropin-releasing hormone
118
Where is GnRH produced and released
It is secreted in pulse, from neuroendocrine cell in hypothalamus
119
Where is gametes produced?
Gonads (ovaries/ testes)
120
What is release from low freq VS high freq of GnRH
Low freq: FSH release
High freq: LH release
121
How is GnRH regulated?
hormone feedback, and higher brain centres
122
What is the freq/ amplitude of GnRH pulse
It changes during development (child, teen, adult), and it control downstream hormone release
123
Where is LH and FSH released from? Where do they act on
Secrete from anterior pituitary, act in gonad
124
What does FSH do?
Follicle stimulating hormone regulate gamete production
125
What does LH do
Luteinizing hormone act on endocrine cell to produce steroid and peptide hormone
In female, regulate gamete production
126
What is special about male urethra
It's shared by both reproductive and urinal system
127
Where is sperm produced?
Produce in testis, and further mature in epididymis
128
What is spermatogonium
Sperm precursor
129
What is sertoli cells (sustentacular cell)
Found within seminiferous tubule, used to support sperm development
Filter and provide nutrients to sperm
130
What is leydig cell ( interstitial cell)
Found outside seminiferous tubule, secrete testosterone
131
Why is there tight junction between sertoli cells?
Sperm is haploid, so it is different from actual cell (diploid), and is identified as foreign by immune system
Tight junction is sertoli cell form blood-testis barrier, so immune cells that circulate in the blood stream will be isolated from the sperm, protecting sperm from immune attack
132
What is spermatogensis? (how is sperm formed)
1: During fetal development, cell undergo mitosis, and form two spermatogonia
2: One spermatogonium stay to produce more, and the under cell pass tight junction, and undergo meiosis, forming spermatocytes
3: After 2 meiosis, 4 spermatids are produced from a singular primary spermatocytes
4: Spermatids undergo spermiogenesis, lose cytoplasm, gain a tail, and mature into spermatozoa
133
What is acrosome
Derived from golgi apparatus
It is found at the head of spermatozoa, which contain enzymes that breakdown the glycoprotein coat that cover the oocyte, helps fertilizing egg
134
Why is mitochondrial spiral found in spermatozoa
It provides ATP for swimming
135
What is the composition of semen
1% spermatozoa, 99% secretion of accessory gland
136
Why are buffer found in semen
Both urethra and vagina are acidic, so buffer is needed to neutralize the acid
137
What is prostaglandins
Found in semen, helps smooth muscle contraction, propeling the content along
138
Why are nutrients found in semen
Sperms are living cells, so need nutrients to help provide energy for swimming
139
How do hormone regulate reproduction in male?
When there are sufficient amounts of testosterone, it will inhibit FSH, LH and GnRH
Testies can produce inhibin hormone, which negative inhibit FSH only
140
What is the role of FSH in male reproduction?
Stimulate sertoli cells, which then support sperm development, secrete inhibin (inhibit FSH release), and secrete androgen-binding hormone which helps concentrate the androgen in testis
141
What does LH do in male reproduction
It stimulate leydig cells, which secrete testosterone in response to LH
142
What is the testosterone secretion during prepubertal and pubertal period
No testosterone during pre-pubertal, and spike during pubertal for reproductive system development
143
What is hypogonadism in XY male
Decreased functional activity of testes, leading to decreased production of androgen, inhibin B, AMH and impared sperm production
144
What is primary hypogonadism
Damage on testis due to genetic or injuries
Leading to low testosterone production, and increased GnRH, LH and FSH level, due to the lack of negative inhibition
145
How is primary hypogonadism treated
By giving exogenous testosterone therapy
146
What is secondary hypogoandism
Problem in hypothalamus/ anterior pituitary gland due to genetic. cancer/ disorders, leading to decrease in GnRH, FSH, LH and testosterone
(low upstream, low downstream)
147
How is treating secondary hypogonadism with exogenous testosterone a problem?
The increase level of testosterone might negative feedback inhibit FSH/LH production, while the FSH/LH level is already low, affecting sperm prodction
148
How is DHT made
Made from testosterone through 5alpha-reductase enzyme
149
How does Finasteride/ Propecia treat male pattern baldness/ benign prostate enlargement
DHT is related to male baldness and prostate growth problem
Finasteride is 5alpha-reductase inhibitor drug, which inhibit DHT formation, lowering DHT level, and treat the problems that are caused by DHT
150
What is fallopian tube
Where egg from follicle is gonna travel through, to the uterus
151
How many ovaries are there in female
2
152
Why uterus has lot of muscle?
Strong smooth muscle contraction can help propelling the fetus out past cervix, during labour
153
What is oocytes?
"egg"
154
What is oogensis (how are oocytes formed)
1: During fetal live, mitosis occur, dividing Oogonium to general oogonia, and mitosis will only occur during the embyotic stage for female
2: Before birth, oogonia enter meiosis 1, duplicating the DNA, but no cell division. Born with primary oocytes
3: After puberty, one primary oocytes will complete meiosis 1, and enter meiosis 2 to become secondary oocytes. This happen once every 28 days
4: Secondary oocytes is released at ovulation, and it stops in metaphase 2
5: If fertilized, it complete meiosis 2 and become zygotes
If it's unfertilized, it dies 12-24 hours after ovulation, and is removed from body
155
What happen to the number of oocytes in female
It declines in number through out the year, and it eventually ran out and end in menopause
156
What is the symmetric of oogenesis? (product symmetric)
It is asymmetric cell division, generating only one secondary oocytes, and a polar body that gets disintegrate
157
How long does oogenesis last
It has limited duration, and stop after menopause
158
What does primary follicles do ?
It surround oocyte in stasis, in the ovary, until puberty
159
How many follicles is recruited in each maturation cycle, and how many is made? What happen to the ramaining one
Around 5-10 follicles in each ovary, and only one will fully mature and ovulated. The remaining oocytes undergo atresia (hormone regulated cell death)
160
What is atresia?
Hormonally regulated cell death
161
What does Granulosa cells do?
Surround oocytes, and supports its development
162
What does theca cells do?
Theca internal and external, secrete steroid hormone precursor (androgens), which convert to estrogen in granulosa cell
163
What are the two cycles in menstrual cycle
Ovarian cycle in ovaries, and Uterine cycle in uterus
164
How long does typical menstrual cycle last
28 days
165
What are the two phase of ovarian cycle
Follicular phase
Lutel phase
166
What are the 3 phase of uterine cycle
Menstrual phase
proliferative phase
secretory phase
167
What happen in follicular phase
Primary follicle containing oocyte develop into secondary follicle, one will be developed into mature follicles (dominant/ graffian), and get ruptured and ovulated
Remaining follicles die through atresia
168
When does follicular phase occur
First half of ovarian cycle, day 1-14
169
What happen to the oocyte during follicular phase
The size stays the same, no growth
170
What is antral fluid/ Antrum
Antrum is the fluid filled cavity in follicles, and abtral fluid contains estrogen and enzymes
171
What happen to theca cell and granulosa cell during follicular phase
Proliferate, and become thicker
172
What is fimbria
Finger like projection located at the end of fallopian tube, which capture the oocytes when ovulated from ovary
173
What happen when LH surge during ovulation
Follicular cells release collagnease that digest the connective tissue, and progesterone that cause muscle contraction
The oocyte and surrounding cumulus cells get expelled to the abdomen between ovary and fallopian tube, and is captured by fimbria
174
What happen to the left behind follicular cells, after ovulation
The theca and granulosa cells become corpus luteum, which release progesterone and estrogen
175
What happen to coupus luteum if no fertilization
Corpus luteum degenerates, and the remaining scar tissue is corpus albicans
176
What happen to coupus luteum if there's fertilization
Corpus luteum continue making progesterone and estrogen to support new fetus development, until the end of first trimester
177
For uterine cycle, what happen during the first phase
First phase= menstrual phase= first day of period
Blood vessels supplying endometrium undergo constriction, cause shedding of endometrial lining due to decline levels of progesteone and estrogen
178
What cuase the female period
Shedding of the endometrial lining, as it is no longer needed, tissues die off
179
What happen during proliferative phase
2nd phase of uterine cycle
Estrogen level increase from ovaries, and endometrium develops in response to estrogen
Blood supply to tissue is reestablished, and cells proliferate, thicken endometrial lining
180
What happen during secretory phase
Final phase of uterine cycle
Endometrium gland secrete more viscous fluid, and the endometrial cells deposit liqid and glycogen in cytoplasm, under the influence of progesterone and estrogen
This is all preparation for providing energy for fetus growth, in case of fertilization
If no fertilization, restart menstrual cycle
181
What happen to endometrial lining as follicle grow
It also grows and thicken
182
What phase of uterine cycle happen right after ovulation
Secretory phase
183
What happen to endothelium lining, if corpus albicans present
Corpus albicans indicate no fertilization, and no more estrogen/ progesterone production
Endometrial lining shed
184
What happen to progesterone level during follicular phase
it remains low, as it can only be produced from corpus luteum
185
What happen to estrogen level during follicular phase
It gradually increase, as follicles (theca cells) can produce estrogen
186
What happen to progesterone level during luteal phase
Spike of progesterone produced by corpus luteum, in preparation forpotential fertilization
187
What happen to estrogen level during luteal phase
Increase, as corpus luteum can make estrogen
188
What event transit follicular phase to luteal phase
Ovulation
189
During early follicular phase (first 5 days, menstrual phase), how is the hormone level?
Low level of estrogen and progesteone
190
After the first 5 days (menstrual phase), what does the LH do?
It stimulates the release of androgen from theca cell
191
After the first 5 days (menstrual phase), what does the FSH do?
It stimulate granulosa cell to convert androgen to estrogen
192
After the first 5 days (menstrual phase), what does the AMH do?
Secreted by granulosa cell, it prevent recruiting extra follicles
193
After the first 5 days (menstrual phase), what does the estrogen do?
Estrogen exert local positive feedback on granulosa cells, so more proliferation, more estrogen converted from adrogen, even more cell growth, even more estrogen...
Estrogen exert upstream negative feedback inhibition at hypothalamus-anterior pituitary, decreasing FSH, LH and GnRH
194
During late follicular phase and ovulation, what happen to FSH?
Tertiary follicles secrete inhibin, which inhibit FSH
195
After the first 5 days (menstrual phase), what happen to hormone level
Increase secretion of progesterone and estrogen, spike
196
After the first 5 days (menstrual phase), what does the progesterone do?
It increase pituitary sensitivity to GnRH
197
After the first 5 days (menstrual phase), what does the estrogen do?
High estrogen increase GnRH pulse frequency, positive feedback causing LH surge, which is essential for ovulation
198
What happen to the hormones during early to mid luteal phase
Under influence of FSH and LH, corpus luteum release progesterone, estrogen and inhibin
These hormone exert upstream negative feedback inhibition at hypothalamus and anterior pituitary, decrease LH and FSH
and also inhibit GnRH pulses
199
What happen to the hormones during late luteal phase, if no fertilization
If no fertilization, corpus luteum dies, and the estrogen and progesterone level drop dramatically. This lost the negative feedback inhibition upstream, so GnRH, LH and FSH release turn on, restarting the process
200
When is a woman most fertile? How to detect
Using ovulation kit, when she has highest LH level, this indicate ovulation about to occur, making her the most fertile
201
Pathway of estrogen formation from cholesterol
In theca cell:
Cholesterol to Progesterone by desmolase
Progesterone to androstenedione by 21-hydroxylase
In granulosa cell;
Androstenedione to estrogen (estrone. estradiol) by aromatase
202
What is the relationship between age and pregnancy
As women age, number of follicles and viability, genetic quality of oocytes all decline and decrease, making pregnancy less successful and the child less healthy (few numbers of poor quality oocyte)
203
What happen to ovaries when menopause
It lost the ability to respond to FSH and LH
204
What happen to hormone level when menopause
Estrogen and progesterone level start to fall, so the negative feedback is lost, causing the rise of FSH and LH level
However, ovaries won't respond to them
205
What is capacitation
Final maturation step of sperm, allowing sperm to become hyperactive for swimming and fertilization
Occur in female reproductive tract
206
What is protagandins
produced in semen, cause uterine contraction, aid transport of sperm
207
What is the viable time for sperm VS oocytes
Oocytes: shorter, only 24 hours
Sperm: longer, for 4-6 days in female
208
What is chemotaxis in fertilization
Progesterone from cumulus cells, chemically attract and guide sperm to reach oocytes
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What is acrosomal reaction
Acrosomal enzymes removes the final layer at the head of the sperm, allowing sperm to pass through barriers and penetrate inside the oocyte, and release genetic info
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How many sperm fill with how many oocytes
One sperm, one egg
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What trigger the acrosome reaction/ cortical reaction
Sperm and egg plasma membrane fuse
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How is zygote nucleus formed?
Sperm penetrate egg, sperm nucleus move into egg cytoplasm, release genetic information
Successful fertilization trigger the completion of meiotic 2
Oocyte nucleus fuse with sperm nucleus, forming zygote nucleus
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What happen to second polar body in egg
After meiosis 2, second polar body get expelled
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How to prevent polyspermy? ( multiple sperm penetrate same oocyte)
Cortical granules (intracellular vesicles of oocyte) fuse with outer membrane, coating the fertilized oocytes
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What is blastocyst
It is the cell structure formed after cell division of zygotes, the early embryo
It reaches and implant on the uterus
It contains the embryo and other structures (placenta)
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Where is hCG secreted from
Trophoblast
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What is trophoblast?
Outer layer of blastocyst, become placenta in the future
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What does hCG do?
After fertilization, it spike in level
Take over from pituitary, maintain corpus luteum and prevent new menstrual cycle
Maintain early pregnancy
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What is the level of hCG after fertilization, till labour
After fertilization, it spikes in level, then decrease and remain a low level until labour
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What is home pregnancy test based on?
The level of hCG, which can be detected 3 weeks after last period
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When is generally consider as the first day of fertilization?
second week after last period
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What is the level of estrogen and progesterone after fertilization
They constantly increase and accumulate to a high level, and drop on the day of delivery
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Why does hCG maintain the corpus luteum? (why do we want corpus luteum to be alive?)
When corpus luteum is maintained, it can continuously secrete progesterone, adn estrogen and inhibin
These hormones suppress upstream through negative feedback inhibition, inhibiting the FSH and LH production
This prevent new menstrual cycle (period), and maintain the uterine environment and endometrium for fetus development
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What does placenta do for fetus
Digestive, respiratory and renal system for fetus, by exchanging nutrients, oxygen and waste, etc
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Where does exchange between mom and baby occur?
Chorionic villi, which is bathed by maternal blood
Maternal blood forms a lacunae(lake) that bath the chorionic villi
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What is the connection between maternal and placental circulation
They are intertwined, but not physically linked
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What is the placenta relationship with hormone?
After first trimester, placenta gets bigger, become a temporary endocrine gland and take over hormone production, independent from ovary now
It produces progesterone, estrogen and human placental lactogen
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WHat is DHEA
estrogen precursor, made in fetal adrenal cortex from cholesterol
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How does placenta secrete estrogen and progesterone? (where to get precursor, and the pathway?)
It receives Cholesterol from maternal blood
Some cholesterol is made into progesterone in placenta, and placenta transport the progesterone out to maternal blood
Placenta passes some cholesterol of fetal blood, which get transported to fetal adrenal cortex and make DHEA
DHEA gets transported to placenta through fetal blood, and made into estrogen in placenta, then transport out to mother's blood
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What are 3 functions of placental progesterone
Suppress uterine contraction (allow baby development), cervical plug, mammary gland development
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What are 2 functions of placental estrogen
Uterine development (house of baby), breast duct development
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What is the level of human placental lactogen in mom VS baby
High in mom, low in fetus
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What is the function of human placental lactogen
Decrease maternal cellular glucose uptake, increase maternal lipolysis
Feed glucose/ nutrients to fetus, benefit fetus development
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What happen to preterm baby born?
Earlier than normal birth, baby lung is not yet developed
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When is normal birth of baby?
37-42 week after last menstrual cycle
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What happen to vasopressin level after pregnancy
Increase vasopressin level, to increase blood volume
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What happen to maternal cardiovascular after pregnancy
Increase output, more blood flow to fetus
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What happen to maternal immune system after pregnancy
Partially suppressed, prevent it from attacking the baby (baby is somewhat foreign to the body)
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What happen to calcitonin level after preganancy
It increases, to limit mobilization of maternal bone
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What is the positive feedback loop of labour?
Fetus drop lower in uterus, cause cervical stretch
Stimulate the release of oxytocin and prostaglandins, which cause uterine contraction
Uterine contraction lead to more cervical stretch, and form positive feedback loop
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What is pitocin
Synthetic oxytocin, which can be used to trigger labour
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What happen to breast milk and hormone before parturition
Estrogen and pregesteron is needed for mammary gland development, but they inhibit milk production
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What are the two hormone needed for break milk production? Where are they made from?
Prolactin and oxytocin, from pituitary gland
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What is the role of oxytocin, in term of breast milk
Stimulate myoepithelial cells, which contract and squeeze out milk
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What is the role of prolactin, in term of breast milk
Stimulate epithelial milk producing cells
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How is breast milk secreted? in term of hormone regulation pathway
Sound of child cry or babby suckling on nipples send stimulate of higher brain centre
Higher brain centre inhibit PIH cells in hypothalamus
Decrease in PIH level remove the inhibition on prolactin, so prolactin and oxytocin level increase, facilitate milk secretion
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What is PIH
Prolactin inhibitory hormone, essentially dopamine
Inhibit prolactin, inhibit breast milk release
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How is sex determined? (male VS female, during gametes fusion)
X or X chromosome in oocyte fuse with X or Y chromosome in sperm
If XX, female
If XY, male
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What is bipotential primordium?
It can be developed into either ovary os testis, depend on the presence of Y chromosome
Y chromosome= develop into testis
No Y chromosome= develop into ovary
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What are rudimentary reproductive tracts
Mullerian duct or wolffian duct
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What happen to mullerian duct/ wolffian duct if Y chromosome is presented
Y chromosome present
Wolffian duct develop into male genitallia due to the presence of tesosterone
Mullerian duct degenerate due to the presence of AMH
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What happen to mullerian duct/ wolffian duct if Y chromosome is absent
Y chromosome absent
Wolffian duct degenerate due to absent of testosterone
Mullerian duct develop into female genitallia due to absent of AMH
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What happen to gonadal cortex and gonadal medulla, if XX chromsomes
Gonadal cortex become ovary
Gondal medulla regress
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What is special about Y chromosome? (why can it make fetus male)
It has SRY gene that encode for transcription factor, promoting testosterone formation
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What happen to fetus if Y chromosome lack SRY gene
Develop into female like structure
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What does SRY code for
Gene regulatory protein, transcription factor that influence downstream gene regulation
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Does testes require testosterone to be formed?
No, it makes testosterone, does no need testosterone to be formed
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What is AMH
Anti mullerian hormone, which cause regression of mullerian, suppress female like structure
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How does SRY lead to its function? (what's the pathway, how to make fetus a male)
SRY drive to the expression of SOX9 and the formation of testis
This lead to development of sertoli cell (produce AMH) and ledig cell (produce testosterone), so female structure is declined
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Where is AMH released from?
Sertoli cell
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What is beta- catenin? (what happen in XX or XY)
XY:
high level of sox 9 suppress beta-catenin, form male like structure
XX:
no SRY, no SOX9
Beta-catenin further suppress sox9, allow the formation of female like sturcture
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What happen to Gonadal cortex/ medulla when XY
Gonadal cortex: regress
Gonadal medulla; form testis
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How is male prostate/ external reproductive structure formed? (what hormone play a role)
DHT, derived from testosterone
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What is a common cause of XY atypical variation in sex determination
atypical androgen synthesis/ action
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What is a common cause of XY atypical variation in sex determination
Excessive exposure to androgen during early gestation
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In general, what is the timing for puberty onset in girl VS boy
Girl is usually earlier than boy
