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Physiology 2 > Mitosis and Meisosis > Flashcards

Mitosis and Meisosis Flashcards

1
Q

diploid cell

A

Cell that contains 2 sets of chromosomes - one from each parent

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2
Q

Germ cell

A

cells that lead to production of gametes - produced by meiosis

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3
Q

Haploid cell

A

Cell that contains one complete set of chromosomes

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4
Q

Meiosis

A

Cellular reproduction that forms 4 haploid cells from one diploid cell. Contains 2 cellular divisions that follow only one round of DNA replication - produces germ cells

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5
Q

Mitosis

A

5 step process by which a cell separates replicated chromosomes before cytokinesis and forms 2 daughter cells from one original cell .

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6
Q

What are the stages of miotosis

A 
Prophase
Prometaphase
Metaphase
Anaphase 
Telophase
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7
Q

Somatic cell

A

Any plant or animal cell that isn’t a germ cell, formed by mitosis

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8
Q

Stem cells

A

Biological cells that can differentiate into other types of cells and divide to produce more of the same type of stem cells. They are always and only found in multicellular organisms

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9
Q

Zygote

A

Fertilised egg cell

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10
Q

Cytoskeleton

A

???

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11
Q

Early prophase

A

cell rounds up into a ball
chromatin begins to condense
nucleolus disappears
centrioles begin to move to opposite poles of cell
microtubules dissolve and reassemble around centrosomes from which they extend

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12
Q

Prometaphase

A

chromosomes condense and arrange into sister pairs - chromatids
chromosomes begin to move
centrioles begin to move to opposite poles of cell
microtubules have formed the mitotic spindle
proteins attach to the centromeres to form kinetochores
spindle microtubules attach to kinetochores and pull on chromosomes
nuclear envelope disperses

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13
Q

Metaphase

A

Paired chromatids align along the cell equator by the mitotic spindle

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14
Q

Midline of cell

A

mitotic plate

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15
Q

Anaphase

A

Paired chromosomes separate at their kinetochores and move to opposite poles along the microtubules

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16
Q

Telophase

A

Chromosomes arrive at opposite poles
new nuclear envelopes form around each daughter nucleus
mitotic spindle disperses
chromosomes disperse as their chromatin becomes diffuse

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17
Q

Cytokinesis

A

Actin ring

cleavage furrow

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18
Q

What holds pairs of homologous chromosomes together?

A

Synapsis

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19
Q

Synapsis

A

Early in prophase 1 homologous chromosomes come together to form a synapse, bound by synaptonemal complex and cohesion proteins

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20
Q

crossing over/ crossover

A

Occurs between homologous chromosomes but not sister chromatids. There is an exchange of genetic material

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21
Q

Primordial germ cells

A

Earliest recogniseable precursors of gametes 24 days after fertilisation in the endodermal layer of yolk sac

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22
Q

Germ cells

A

exit from the yolk sac and migrate through dorsal mesentery to primordia of gonads

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23
Q

what is oogenesis

A

development of an ovum

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24
Q

What is spermatogenesis

A

development of a mature spermatozoa

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25
Q

Oogenesis

A

primordial germ cells develop in yolk sac > oogonium (in gonads) > mitosis > oogonium > start meiosis 1 > primary oocytes arrested in prophase 1 (at birth) > 1st meiotic division producing polar body > secondary oocyte arrested in metaphase 2 during ovulation > 2nd meiotic division producing polar body > mature ovum > fertilised egg

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26
Q

Spermatogenesis

A

Primordial germ cells in yolk sac > spermogonium > mitosis > primary spermatocytes > 1st meiotic divisions > secondary spermatocytes > 2nd meiotic divisions > spermatids > spermatogenesis packaging > spermatozoa

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27
Q

Symptoms of pregnancy

A 
Varicose veins
Anaemia
Flushed and hot
Breast enlargement
Pelvic pain
swollen ankles
morning sickness 
constipation
heartburn
breathless
urinary infection
urinary frequency 
glucose in urine
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28
Q

What causes pregnancy symptoms

A 
Adaptations in the...
respiratory system
renal system
cardiovascular system
metabolism
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29
Q

Positive feedback systems in pregnancy

A

prolactin secretion in breast feeding
oxytocin secretion in labour
oestrogen secretion by follicles to trigger ovulation

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30
Q

Ovulation

A

hypothalamus releases Gonadotropin-releasing hormone which acts on anterior pituitary gland to release FSH which stimulates growth and development of follicle. Oestradiol from maturing follicle stimulates release of LH which stimulates ovulation and corpus luteum formation

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31
Q

Luteal phase

A

corpus luteum releases progesterone which prepares the uterus
corpus luteum not sustained in the absence of fertilisation

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32
Q

Fertilisation

A

spermatozoa and oocyte fuse and undergo mitosis which forms a blastocyst.

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33
Q

Post-fertilisation

A

Blastocyst secretes hCG which supports the corpus luteum corpus luteum continues to release progesterone and oestrogen which sustains the uterus.

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34
Q

When is the hCG peak?

A

between week 2 and week 14

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35
Q

What is hCG?

A

Human Chorionic Gonadotropin

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36
Q

hCG

A

glycoprotein hormone, which is rapidly secreted from trophoblast. Used for pregnancy testing and causes morning sickness

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37
Q

What can hCG be a sign of

A

Pregnancy
ectopic pregnancy
trophoblastic tumours
pineal tumours

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38
Q

Miscarriage

A

If progesterone fails for any reason the endometrium and developing embryo are shed producing a miscarriage and the corpus luteum dies

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39
Q

What hormones are produced by the placenta?

A

Progesterone - takes over from corpus luteum by weeks 10-12
Oestrogen
hCG
Human placental lactogen

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40
Q

Where is progesterone synthesised?

A

Placenta

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41
Q

What affect does progesterone have on uterus?

A

smooth muscle relaxation preventing fetal expulsion and cervical plug formation which acts as a microbial barrier.

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42
Q

What does progesterone target?

A

uterus
homeostasis
breast
relaxes other smooth muscle in the body - blood vessels, GI tract, ureters and bronchi

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43
Q

What does progesterone do to homeostasis?

A

Hyperventilation

weakly stimulates sodium reabsorption and increases water recovery - causing water retention

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44
Q

What does progesterone do to breasts?

A

stimulates development of lobular tissue but inhibits milk production

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45
Q

what is lobular tissue?

A

milk producing glands and ducts of the breast

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46
Q

when do progesterone levels fall?

A

last few days of pregnancy

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47
Q

What does oestrogen affect?

A

uterus

breasts

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48
Q

what does oestrogen do to the uterus?

A

myometrial cell growth - for growing fetus, connexin insertion - electrochemical links (gap junctions) between myometrial cells
oxytocin receptor insertion in prep for labour
PGE2 production stimulated which softens the cervix

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49
Q

what does oestrogen do to the breast?

A

breast duct development

but inhibits milk production

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50
Q

oestrogen production

A

complex production as placenta is unable to produce the enzyme needed to convert progestogens to androgens so fetal contribution is needed

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51
Q

normal hypothalamic pituitary axis

A

hypothalamus produces corticotropin releasing hormone which causes the anterior pituitary to produce corticotropin > adrenal cortex produces cortisol

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52
Q

How is oestrogen produced in pregnancy?

A

Placenta secretes corticotropin releasing hormone > causes anterior pituitary in mother and fetus to secrete corticotropin which acts on the adrenal cortex in fetus and mother to secrete cortisol and DHEA in fetus and just cortisol in mother. DHEA > oestrogen > supports pregnancy

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53
Q

what does cortisol do to fetus?

A

lung maturation

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54
Q

what does a sudden surge of CRH do?

A

triggers labour

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55
Q

oestrogen levels over pregnancy

A

increase over 40 weeks and sharply decline after birth

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56
Q

what does human placental lactogen affect?

A

mother and fetus

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57
Q

what does human placental lactogen do in the mother?

A

insuline resistance - decreases glucose utilisation and increases blood glucose
Lipid breakdown - generates free fatty acids
breast development
has similarities with growth hormone

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58
Q

what does human placental lactogen do in fetus?

A

promotes growth due to more glucose available from mother by insulin resistance

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59
Q

what happens to blood volume in pregnancy?

A

vascular capacity increased by utero placenta circulation

blood loss expected at delivery

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60
Q

what happens to blood oxygen carrying in pregnancy?

A

O2 requirements increase - greater maternal and fetal needs

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61
Q

What happens to blood clotting in pregnancy?

A

haemostasis required when placenta shears off after delivery. In pregnancy there is a drop in anti-thrombin levels and so blood is in a pro-thrombotic state

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62
Q

Anaemia in pregnancy

A

due to increase in blood plasma there are fewer RBCs for the volume of blood - functional anaemia despite the increase in red blood cell mass

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63
Q

what chemicals are needed more in pregnancy?

A

Folate

Iron

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64
Q

what happens to the heart in pregnancy?

A

more oxygen needed and circulation distance increased

increased abdominal mass moves heart upward and out

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65
Q

how is BP calculated

A

cardiac output x systemic vascular resistance

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66
Q

how is cardiac output calculated

A

stroke volume x heart rate

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67
Q

what happens to cardiac output in pregnancy

A

increase in venous return causes increase in stroke volume - starling’s law and due to oestrogen which increases contractility. This increases cardiac output, as does oestrogen by increasing heart rate

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68
Q

what happens to BP in pregnancy?

A

as cardiac output has increased by 45% systemic vascular resistance has to fall to maintain BP.

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69
Q

How does systemic vascular resistance fall

A

renal blood blow doubled
large utero-placental bed takes blood
skin blood flow increase by 5 times - helps lose heat - causing flushed and hot feeling
Vasodilation caused by progesterone

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70
Q

pregnancy impact on veins

A

venous compression due to expanding uterus, impairs venous return causing pooling and distension - varicose veins

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71
Q

how can pregnant women not position themselves?

A

lying on left side

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72
Q

What happens to the lungs in pregnancy?

A

oxygen consumption and CO2 production increase and the diaphragm is displaced by abdomen

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73
Q

respiratory changes in pregnancy

A

tidal volume increase
resp. rate unchanged
airway resistance and functional residual capacity drops. partial pressure of CO2 is lower

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74
Q

what causes respiratory changes in pregnancy?

A

progesterone

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75
Q

carbon dioxide control in pregnancy

A

progesterone increases sensitivity of chemoreceptors to CO2 which increases ventilation and drops the pressure of CO2 - breathlessness

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76
Q

What happens in the kidneys in pregnancy?

A

increased perfusion due to increased plasma volume, decreased reno-vascular resistance and increased cardiac output and decreased plasma oncotic pressure due to dilution

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77
Q

why is there an increase in urine production in pregnancy?

A

increase in glomerular filtrate rate
greater reabsorption but still more urine produced
glucose in urine as filtered glucose may exceed reabsorption limit

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78
Q

Later in pregnancy what is the main cause of urinary frequency?

A

Pressure on bladder by enlarging uterus

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79
Q

fluid changes in pregnancy

A

aldesterone activated to ensure too much sodium isnt lost
osmoregulation changes and so plasma osmolarity dropping doesn’t cause more water loss
results in retention of water and sodium - swollen ankles
all caused by progesterone

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80
Q

metabolism in pregnancy

A

metabolic rate increases

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81
Q

Changes in GI tract in pregnancy

A

slower transit - constipation
increased nutrient absorption
oesophageal reflux - heart burn

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82
Q

breast changes

A

oestrogen - mammary duct development
progesterone - lobular tissue development
these both inhibit prolactin which stimulates milk production

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83
Q

what happens in breasts after delivery

A

drop in oestrogen and progesterone stops inhibition of prolactin so milk production occurs and oxytocin causes milk ejection

84
Q

what causes prolactin release

A

nipple stimulation causes hypothalamus to release prolactin releasing hormone which causes anterior pituitary to secrete prolactin

85
Q

what does prolactin do

A

suppresses ovulation and causes breast tissue development in pregnancy and causes milk production after pregnancy

86
Q

what causes oxytocin release

A

nipple stimulation and cervix/ vaginal distension cause oxytocin production in hypothalamus and release from posterior pituitary

87
Q

what does oxytocin do?

A

uterine contraction and milk ejection - myoepithelial cell contraction

88
Q

Glands

A

epithelial tissue derivatives specialised for secretion

89
Q

secretion

A

biochemical release from a particular type of cell upon stimulation

90
Q

endocrine glands

A

secretions enter bloodstream - ductless glands

91
Q

exocrine glands

A

gland with ducts that channels its secretion

92
Q

hormone

A

chemical messengers secreted into the blood by endocrine glands in response to an appropriate signal and exerting their effects on target cells that have receptors that bind with the hormone

93
Q

types of hormones

A

hydrophilic and lipophilic

94
Q

what hormones are hydrophilic

A

peptides and catecholamines

95
Q

what hormones are lipophilic

A

steroids and thyroid hormone

96
Q

peptide hormones

A

produced by protein synthesis, travel in blood, cannot enter cells, bind to cell surface receptor, trigger event on inside surface of membrane
fast acting

97
Q

Steroid hormones

A 
produced by modification of cholesterol molecule by enzymes
travel in blood bound to plasma proteins
enter cells easily
intracellular receptor
act on DNA to alter cell function
slow acting - time for transcription
98
Q

why is the type of hormone important?

A

affects administration, peptide hormones cannot be given orally as they will be digested in the stomach

99
Q

how do peptide hormones work

A

bind to receptor on outside of cell and cause ATP conversion to cAMP

100
Q

how do steroid hormones work?

A

pass through phospholipid bilayer and bind to receptor on gene, causing protein synthesis leading to cell response

101
Q

role of endocrine system

A 
metabolism, water and electrolyte balance
stress response
growth and development
reproduction
RBC production
coordination of circulation
coordination of digestion
102
Q

endocrine glands

A 
hypothalamus
pituitary
thyroid
parathyroid
adrenal cortex
adrenal medulla
kidney
stomach
pancreatic islets
duodenum and jejunum
ovary
testis
103
Q

pituitary

A

anterior and posterior lobe

connects to hypothalamus via pituitary stalk

104
Q

hypothalamus

A

controls pituitary hormone release

interface between events inside and outside the body and their endocrine response

105
Q

what hormones are released by hypothalamus?

A 
corticotropin releasing hormone
thyrotropin releasing hormone
somatostatin
gonadotropin releasing hormone
growth hormone releasing hormone
prolactin releasing hormone
prolactin inhibiting factor
106
Q

anterior pituitary

A

controls activity of other endocrine glands
involved in ovulation and pregnancy
sperm production
growth

107
Q

what hormones are released by anterior pituitary gland?

A 
thyroid stimulating hormone
adrenocorticotrophic hormones 
luteinising hormone 
follicle stimulating hormone 
growth hormone
prolactin
108
Q

how is the hypothalamus and pituitary linked?

A

anterior pituitary - blood vessels

posterior pituitary - neurones

109
Q

posterior pituitary

A

involved in regulating water balance
uterine contraction
ejection of milk

110
Q

what hormones are released by posterior pituitary?

A

ADH

oxytocin

111
Q

what is the process of hormones of thyroid?

A

HPT axis

112
Q

what is the process of hormones of reproduction?

A

HPG axis

113
Q

what is the process of hormones of adrenal gland

A

HPA axis

114
Q

Testis

A

releases testosterone
which:
masculinises the reproductive tract and external genitalia
promotes growth and maturation of reproductive system at puberty
spermatogenesis
develops sex drive
secondary sexual characteristics

115
Q

ovaries

A 
release oestrogen and progesterone 
which:
mature and maintain reproductive system
female secondary sexual characteristics
ova maturation and release
transport of sperm to site of fertilisation
preparing uterus for development of embryo and foetus
contribute to ability to produce milk
116
Q

thyroid

A

controls metabolic rate
increases heart rate
needed for normal growth and development

117
Q

what hormones does thyroid release?

A

triiodothyronine (T3)

thyroxine (T4)

118
Q

parathyroid

A

calcium metabolism

raises free plasma calcium by mobilising bone stores, reducing urine loss and increasing gut absorption

119
Q

what hormones does the parathyroid release

A

PTH

120
Q

kidney

A

releases renin if circulating volume or BP is low - sodium is retained and volume restored. releases erythropoietin when hypoxic to increase RBC formation in bone marrow

121
Q

hormones released by kideny

A

renin - stimulates aldosterone release from adrenal cortex

erythropoietin

122
Q

adrenal cortex

A

metabolic response to stress

body sodium levels

123
Q

what hormones are released by adrenal cortex?

A

cortisol
aldosterone
DHEA

124
Q

adrenal medulla

A

fight/ flight response

125
Q

what hormones does the adrenal medulla release

A

catecholamines

126
Q

what hormones are involved in digestion and food absorption?

A 
gherlin
gastrin
secretin and CCK
GIP
Peptide YY3-36
insulin
glucagon
somatostatin
127
Q

what does gherlin do?

A

stimulates appetite

128
Q

what does gastrin do?

A

stimulates HCL production for protein digestion

129
Q

what does secretin and CCK do?

A

coordination of digestive functions

130
Q

what does Peptide YY do?

A

signals satiety

131
Q

what does somatostatin do?

A

inhibits absorption of nutrients

132
Q

adipose tissue

A

endocrine gland

133
Q

what does adipose tissue secrete?

A 
visfatin
apelin
leptin
TNF-alpha 
adiponectin
RBP-4
resistin 
many causing insulin resistance
134
Q

Which axis is involved in the formation of mature sperm?

A

HPG axis

135
Q

HPG axis

A

Hypothalamus produces CnRH > pituitary releases FSH and LH > FSH acts on Sertoli cells and LH on Leydig cells

136
Q

Where are Sertoli cells found?

A

Seminiferous tubule of testes

137
Q

Where are Leydig cells found?

A

Interstitium of testes

138
Q

What do Sertoli cells do?

A

in response to FSH they produce Androgen binding protein which causes spermatogenesis

139
Q

what do Leydig cells do?

A

Produce testosterone in response to LH.

140
Q

What does testosterone do?

A

allows sertoli cells to produce androgen binding protein, which than binds to testosterone and causes spermatogenesis and
peripheral effects

141
Q

what are the peripheral effects of testosterone?

A

maintain libido
muscle bone growth
secondary sex characteristics
accessory gland maintenance

142
Q

Negative feedback of the HGT axis in males

A

Inhibin is produced by Sertoli cells which reduces FSH production by pituitary which reduces androgen binding protein levels

143
Q

Testosterone affect on negative feedback of HPG axis

A

rise in testosterone levels causes reduced production of GnRH by hypothalamus and decreased production of LH and FSH by pituitary

144
Q

which cells are affected by testosterone

A

sustentacular cells of seminiferous tubules

145
Q

Phases of spermatogenesis

A

spermatocytogenesis

Spermiogenesis

146
Q

what happens in spermatocytogenesis

A

germ cell undergoes cell division to form spermatids

147
Q

What happens in spermiogenesis

A

maturation and differentiation of spermatids

148
Q

what are spermatids

A

immature sperm

149
Q

what are leydig cells

A

interstitial cells

150
Q

where are sertoli cells?

A

around outside of lumen of testes, surrounded by basement membrane

151
Q

what is spermiogenesis

A

remodelling and differentiation into mature spermatozoa

152
Q

what are the phases of spermiogenesis

A

golgi
acrosomal
tail
maturation

153
Q

what happens in the golgi phase

A

golgi body enzymes form the acrosome

154
Q

what happens in the acrosomal phase

A

acrosome condenses around the nuclues which allows it to penetrate the egg and protects the nucleus

155
Q

what happens in tail phase

A

centriole elongates to form the tail

156
Q

what happens in maturation phase

A

loss of excess cytoplasm to make it aerodynamic

157
Q

What is spermiation?

A

process by which mature spermatozoa are released from the protective sertoli cells into the lumen of the seminiferous tubule and the remaining unnecessary cytoplasm and organelles are removed.
The spermatozoa are mature but lack motility - so are sterile . They are transported to the epididymus in testicular fluid secreted by sertoli cells and peristaltic contraction . Sperm travel and stored in vas deferens, this is aided by secretions of the seminal gland, they gain motility

158
Q

Making spermatozoa fertile

A

once motile sperm are still not fertile they have to undergo capacitation

159
Q

Capacitation

A

A glycoprotein coat covers the acrosome and prevents the sperm fertilising the egg. Capacitation happens due to enzymes fertilisation promoting peptide (produced by prostate gland) and heparin in female reproductive tract which remove the coat and allow sperm to bind to the egg .

160
Q

FPP

A

produced in prostate gland as a component of seminal fluid. High levels in MRT prevent capacitation but they drop in the FRT and promotes capacitation

161
Q

sperm transport into FRT

A

ejaculate is deposited in the anterior vagina near the cervix . The vagina is open to infection so has high acidity and immunological defence so to reduce the risk of damage to sperm they must travel quickly through the cervical canal. The cervix is only penetrable at certain points of the month - when there is a watery mucus and oestrogen levels are high - 2-3 days per cycle. The cervix has crypts - infoldings of epithelial cells in the endocervical canal which create a reservoir for sperm so they can be released over several hours and chance of fertilisation is increased .

162
Q

what is in ejaculate?

A

spermatozoa
seminal fluid
enzymes - protease, seminalplasmin, prostatic enzyme and fibrinolysin

163
Q

normal semen

A

more than 1.5ml

pH higher than 7.2

164
Q

normal sperm

A 
conc. = >15 million/ ml 
total no. = >39 million per ejaculate
total motility = >40% or >32% with progressive motility 
vitality = >58% live spermatozoa 
sperm morphology = >4%
165
Q

Blood testing for fertility

A

hormone profile - FSH, LH, Testosterone and prolactin

166
Q

History taking for fertility

A

libido status, erectile dysfunction, diabetes, retrograde ejaculation, taking drugs that may affect erection

167
Q

Examine penis and scrotum

A 
size 
STD symptoms
hypospadias 
urethral meatus - hole may be in wrong place 
texture 
scar tissue
inflammation
ductus deferens
blockages
168
Q

hypogonadism

A

diminished functional activity of the gonads - testes or ovaries, may result in diminished production of sex hormones
due to testicular disorder or disease involving hypothalamus and pituitary gland

169
Q

Hypergonadotrophic hypogonadism

A

issues with testes or ovaries - primary/ peripheral hypogonadism
When there is a problem with testosterone production it causes low levels which sends signals to hypothalamus causing more GnRH to be released and more FSH and LH but testes are damaged so testosterone remains low. Presentation = high FSH, LH and GnRH but low Testosterone

170
Q

Hypogonadotrophic hypogonadism

A

low testosterone because there is low gonadotrophin because there is a problem with the hypothalamus

171
Q

What causes hypogonadotrophic hypogonadism

A

kallmann syndrome
drugs
alcohol
infectious lesions

172
Q

What causes high prolactin, and low testosterone, LH and FSH

A

Hypersecretion of prolactin
caused by pituitary tumours and is drug induced
leads to inhibition of GnRH - reduces LH, FSH and testosterone
causes low libido and erectile dysfunction

173
Q

what does prolactin do?

A

inhibits release/ reduces release of GnRH

174
Q

Follicular phase of menstrual cycle

A

pre-ovulation
Hypothalamus releases GnRH which causes anterior pituitary to release FSH and LH
FSH causes 15-20 follicles to start developing and this causes the granulosa cells around follicles to secrete oestrogen

175
Q

Phases of menstrual cycle

A

follicular phase
luteal phase
14 days each

176
Q

which phase is always 14 days in the menstrual cycle

A

luteal phase

177
Q

What does FSH do?

A

stimulates development of follicles

178
Q

What does LH do?

A

Causes ovulation

179
Q

What does oestrogen do?

A

promotes female secondary characteristics
develops breast tissue, vulva, vagina and uterus and endometrium
stimulates blood vessels in uterus
causes mucus in cervix to become thinner to allow penetration of sperm
Causes negative feedback

180
Q

Oestrogen…

A

causes negative feedback on hypothalamus and anterior pituitary. Rise in oestrogen suppresses release of FSH and LH

181
Q

What happens just before ovulation?

A

dip in oestrogen as follicles get ready to release egg

rise in LH which causes 1 follicle to reach surface of ovary and release the ovum at day 14

182
Q

luteal phase

A

follicle that released ovum collapses and becomes corpus luteum and releases progesterone

183
Q

when does ovulation happen?

A

day 14

184
Q

what does progesterone do?

A

steroid sex hormone
thickens and maintains endometrium
thickens cervical mucus
increase body temperature

185
Q

corpus luteum

A

secretes progesterone and oestrogen

186
Q

what happens if egg is fertilised

A

embryo secretes hCG

maintains corpus luteum

187
Q

what happens if egg is not fertilised

A

corpus luteum degenerates and no long produces progesterone and oestrogen. this reduces negative feedback causing FSH and LH to be secreted
drop in oestrogen and progesterone causes endometrium to break down causing menstruation

188
Q

when does menstruation start?

A

day 1

189
Q

menstruation

A

where superficial and middle layers of endometrium separate from basal layer and are broken down in uterus and released through cervix and vagina
lasting 1-8 days

190
Q

development of ovarian follicles

A

primordial follicle > primary follicle > secondary follicle > graafian/ mature follicle > ovulation

191
Q

what does oestrogen do in negative feedback

A

as oestrogen is produced it causes reduction of FSH production
basal level of LH

192
Q

mature follicle

A

produces large amounts of oestrogen which causes positive feedback and increases LH production via GnRH - causes LH surge. FSH is produced but inhibin prevents surge of FSH

193
Q

What does the LH surge do?

A

restarts meiosis
oocyte undergoes another meiotic division
activates enzymes that break down wall to rupture follicle
oestrogen production stops as follicle dies

194
Q

luteal phase

A

progesterone inhibits FSH and LH to stop further follicle development and ovulation
prepares uterus for pregnancy
oestrogen should cause positive feedback but is overridden by progesterone negative feedback

195
Q

if fertilisation does not occur

A 
corpus luteum degenerates spontaneously
progesterone fails
uterus loses its endocrine support
menstruation 
FSH and LH gets to work again on follicles
196
Q

what are the 2 layers of the uterine wall

A

myometrium

endometrium

197
Q

what does oestrogen do to the uterus

A

promotes growth of endometrium and myometrium

promotes formation of progesterone receptors

198
Q

what does progesterone do to the uterus?

A

acts on oestrogen-primed endometrium
loosens and softens connective tissue - making implantation easier
promotes secretion of nutrients
quietens uterine activity

199
Q

uterine loss

A

no occupants so no hCG, so corpus luteum degenerates
progesterone and oestrogen support lost
uterine prostaglandins cause vasoconstriction and tissue death
blood and endometrial debris loss through vagina

200
Q

menstrual disorders

A

dysmeorrhea
mennorrhagia
amenorrhea
oligomenorrhea

201
Q

what is dysmenorrhea?

A

painful periods

202
Q

what is Menorrhagia?

A

heavy or prolonged periods

203
Q

What is amenorrhea?

A

absence of periods

204
Q

what is oligomenorrhea

A

light periods

205
Q

how does the combined pill work?

A

low dose of oestrogen = reduces FSH from ant. pituitary, reduces development of follicle and no ovulation

Progestrogen = makes cervical mucus sperm-unfriendly
decreases LH from ant. pituitary and GnRH from hypothalamus
reduces motility of fallopian tube

206
Q

what makes up the combined pill

A

progestogen

low dose of oestrogen

207
Q

Progestogen only pill

A

low dose of progestogen taken continuously
makes cervical mucus inhospitable to sperm
hinders implantation - effect on endometrium and motility and secretions of fallopian tubes
menstruation - often ceases initially but returns long-term
causes breakthrough bleeding and irregular menses

Physiology 2 (20 decks)

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