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module 1.06 Flashcards

1
Q

The brain produces 3 hormones involved in the male and female reproductive system, what are their names and where are they secreted from?

A

GnRH (Gonadotrophin realising hormone) is realesed by the hypothalamus and travels by blood to trigger the secretion of LH (lutenising hormone) and FSH (follicle stimulating hormone) from the anterior pituitary gland.

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2
Q

How do FSH and LH travel to the testes?

A

via the bloodstream

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3
Q

Where in the testes do LH and FSH travel to?

A

the interstitial space of the seminifer tubule

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4
Q

what cells are found in the seminiferous tubule region?

A

sertoli cells (‘nurse cells’), spermatagonia

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5
Q

The action of LH in the testes

A

1) enters intersititial space and targets leydig cells

2) stimulate leydig cells to secrete testosterone

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6
Q

what are the peripheral affects of testosterone in the body?

A

1) maintain sexual drive
2) stimulate bone and muscle growth
3) maintenance of male secondary characteristics (deep voice, beard, etc)
4) maintenance of accessory glands and organs in the male reproductive system

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7
Q

What happens if testosterone levels are too high?

A

negative feedback loop: high levels of testosterone, inhibits secretion if LH from the anterior pituitary gland

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8
Q

The action of FSH in the testes

A

1) enters interstial space

2) targets sertoli cells which stimulates ABP (antigen binding protein) release and inhibin release

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9
Q

What is the function of ABP (Antigen binding Protein) ?

A

promotes sperm growth
SPERMATOGENSIS and SPERMIOGENESIS
spermatogoa enter the lumen of the seminiferous tubule

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10
Q

what is the action of ABP? (male reproductive system)

A

ABP binds to androgen (testosterone) in the seminiferous tubule which will in turn stimulate sperm production

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11
Q

What two things are requires for sperm production?

A

ABP and testosterone

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12
Q

what happens if FSH levels are too high (in males)?

A

FSH targets sertoli cells which will release inhbin, inhibin travels via blood to the anterior pituitary gland and inhibits release of FSH. This is to control and regulate sperm production.

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13
Q

what 2 phases can the menstural cycle be split into?

A 
follicular phase (first 14 days)
luteal phase (last 14 days)
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14
Q

What happen in the follicular phase of the menstural cycle?

A

FSH will enter the ovaries and stimulate follicule maturation of primary follicles. As some primary follicles mature to secondary follicles oestrogeon is produced. before 10 days: LH remains low and constant. FSH drops towards end due to rise in oestrogeon levels.

after 10 days: follicles continue to mature so increase levels of oestrogeon causing the secretion of LH. increased levels of LH causes ovulation

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15
Q

what is the effect of low conc of oestrogeon in the blood?

A

in low concentration oestrogeon will inhibit the secretion of LH. (counteracts GnRH so LH levels are constant).
FSH is primarily secreted in response to low oestrogeon (high oestrogeon levels lower FSH levels)

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16
Q

What are the peripheral effects of oestrogeon?

A

1) stimulate bone and muscle growth
2) stimulate endometrial growth
3) maintains secondary female characteristics
4) maintain glands

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17
Q

What happens in the luteal phase of the menstural cycle?

A

After the follicle ovulates the follicule will turn into a corpus luteum (a dead follicle).
Corpus luteum will produce 3 hormones: oestrogeon, inhibin and progesterone.
As corpus luteum degenerates progesterone decreases, (GnRH is no longer inhibited)

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18
Q

what is the function of inhibin in the luteal phase?

A

inhibin will inhibit release of FSH (as in this phase no more follicles need to mature)

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19
Q

Functions of progesterone?

A

1) inhibit release of GnRH from hypothalamus

2) stimulate endometrial growth

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20
Q

what causes the period?

A

After corpus luteum degrades progesterone levels drop meaning endometrial lining cannot be maintained and it sheds causing the period.

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21
Q

https://media.memorang.com/images/144e528f-6e6b-43e9-8eed-9d8a5b2805ed.jpg

A

1) posterior superior illiac spine
2) posterior inferior illiac spine
3) greater sciatic notch
4) ilium
5) ischium
6) ischial tuberosity
7) pubic tubercle
8) accetabulum
9) illiac crest

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22
Q

what surrounds the occyte?

A

zonapellucida, further surrounded by cells of the corona radiat

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23
Q

what is cleavage and where does it occur?

A

The division of a zygote into multiple cells as it travels along the uterine tubes

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24
Q

what forms at roughly day 4 after fertillisation?

A

morulla (16 cells)

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25
when a morulla divides again what is formed? Day 5
blastocyst (32+ cells), all are embryonic cells
26
what happens so the blastocyst can implant? Day 7
the blastocyst sheds zona pellucida
27
what makes up blastocyst?
embryoblast, mass that forms baby | trophoblast, outter mass that forms placenta
28
what hormone do trophoblast cells secrete?
hCG
29
when does the zonapellucida develop?
five days after fertillisation
30
what must the spermatozoa undergo for fertillisation to occur?
Capacitation- Removal of glycoprotein coat + and seminal plasma proteins, aided by uterus epithelium Acrosome reaction-Hyaluronidase and trypsin, digests cumulus cells. Acrosin, digests zona pellucida Fusion of plasma membranes
31
what does the trophoblast differentiate into?
cytotrophoblast and syncytiotrophoblast
32
what are the properties of the synchtiotrophoblast?
- has no cell membrane - blastocyst becomes buried in the endometrium and 1/3 more the myometrium - secretes hCG, maintaining the corpus luteum - secretes enzymes that digest endometrial layer to help with implantation
33
what is the purpose of the cytotrophoblast?
penetrates maternal arteries and routes the blood flow through the placenta for the embryo
34
what does the embryoblast differentiate into?
Hypoblast- primitive endoderm (cuboidal cells), Epiblast- primitive ectoderm (columnar cells) -forms each layer of the bilaminar disk
35
what is the amniotic cavity to begin with?
a small cavity which appears above the epiblast, and the epiblast forms the floor of this cavity
36
what happens to the cytotrophoblast upon implantation?
some of the cells start proliferating and their cell membranes disintegrating (outside of the zona pellucida), this forms a sort of cytoplasm consisting of the nuclei of these cells. This is called the syncytiotrophoblast. some cells remain with well defined cell margains and stay as cytotrophoblast.
37
how does the primitive yolk sac form?
hypoblast gives rise to Exocoelomic membrane (by cells migrating and covering the inner surface of the blastocyst wall) -> columnar cells become squamous to form the exocolmic membrane. These two things combined forms the primitive yolk sac below the hypoblast.
38
what is amniotic fluid derived from?
amniotic fluid is derived from maternal blood but also from the urine of the embryo.
39
what is the function of the amniotic fluid?
- prevent adhesion between skin and tissue | - regulate temprature
40
what are maternal sinusoids?
they form when endometrial capillaries around the embryo become dilated. (after lacunae are formed)
41
how do lacunar networks form?
synctiotrophoblast expands allowing lacuna to form with in it, lacunae then fuse to form lacunar networks.
42
how is uteroplacental circulation formed?
Enzymes from the synctiotrophoblast erode the maternal sinusoids and endometrial glands, maternal blood and uterine secretions from glands enter the lacunar networks. establishing the uteroplacental circulation.
43
mitrochondrial inheritance
44
genetic techniques
45
How does the extraembryonic mesoderm form?
Form between inner surface of trophoblast and exocoelomic cavity and membrane Derived from primitive yolk sac Loose connective tissue
46
what happens when large caviities form in the extraembryonic mesoderm?
Large cavities develop that becomes confluent Extraembryonic coelom (chorionic cavity) Surrounds primitive yolk sac and amniotic cavity
47
what is the connecting stalk?
connects germ disk to cytotrophoblast, later becomes umbilical cord
48
one similarity and one difference between primitive and secondary yolk sac?
similarity: derived from hypoblast difference: secondary yolk sac is much smaller than the primitive yolk sac
49
what are the 3 germ layers?
ectoderm, mesoderm, endoderm
50
what does the trophoblast layer develop into?
the chorion
51
what does the inner cell mass of the blastocyst develop into?
the embryo and the amnion
52
what are the 4 main sacs of the embryo?
- Allantois (Allantoic sac) - Amnion (Amniotic sac) - Chorion (Chorionic sac) - Yolk sac
53
what is the primitive streak?
a thickening of epiblast cells
54
where is the primitive node?
at the end of primitive streak towards the cranial end and in the epiblast.
55
how is epithelial migration able to occur?
inhibition of E-cadherin protein (as cells surounding primitive streak and node secrete FGF-8) so cells are no longer stuck together and are able to move.
56
what is primitive groove and the primitve pit?
cells with in the primitive streak and the primitive node die to form the primitve groove and the primitive pit
57
How is the endoderm formed?
epiblast cells are now able to move through the primitive groove and replace the hypoblast to form a layer called the endoderm.
58
How does the Mesoderm form?
epiblast cells move through the primitive grove and forms the mesoderm layer inbetween the endoderm nd the ectoderm.
59
what is the process of the bi-laminar disc becoming the tri-laminar disc?
Gastrulation
60
how does the notochord form?
epiblast cells move through the primitive pit and move crainally towards the prochaudal plate to create a tube like structure between the ectoderm and endoderm. (no mesoderm where the notochord is)
61
Where is there no mesoderm?
prechaudal plate, cloacal plate and notochord
62
Why is the notochord important?
The nodal chord helps to induce neuralation
63
How does the neural plate form?
notochord secretes certain types of growth factors and proteins which stimulates ectodermal cells to proliferate and thicken and form the neural plate.
64
What is the neural grove?
A divet in the neural plate
65
how do crest cells start to form?
from the neural plate and part of the neural grove which are trying to touch, cells in neural fold start to differentiate to form neural crest cells.
66
How does the neural tube form from the neural groove?
Neural folds eventually touch one another and fuse together then go underneath the endoderm and form the neural tube inbetween the endoderm and ectoderm.
67
What does the neural tube become?
neural tube becomes the central nervous system
68
What can neural crest cells become? (CRESTCELL)
``` Chromaffin cells, Rostral tissues (tissues in head and neck), Enteric nervous system, Schwarnn and satellite cells The peripheral nervous system Carotid bodies Endocardial cushions (septum and valves) Melanocytes (give skin its colour) Leptomeninges (pia and arachnoid) ```
69
What placodes are found in the ectoderm?
Olfactory placode, Lens placode, Otic placode
70
describe the process of neuralation
1) Lateral edges of the ectoderm elevate to form the neural folds. The depression is the neural groove. The whole thing is now referred to as the neural plate. 2) Cranial end of the neural tube forms the brain, and the caudal end forms the spinal cord. Neural folds from both ends eventually fuse to form the neural tube. Fusion starts in the middle and advances both cranially and caudally. 3) Outer parts of the ectoderm will descend to surround the endoderm and mesoderm. Some ectodermal cells migrate from the neural tube to forms the neural crests cells (spinal & cranial nerves, ganglia, PNS, meninges, all structures that have pigment). Remaining ectoderm forms the skin
71
How is Spina Bifida caused?
incomplete closure of neural pore, which is reliant on a reliant supply of folate
72
when the CNS forms what were the 3 primary vesicles and what do they become to form the 5 secondary vesicles?
forebrain- telencephalon -> cerebral hemisphere diencephalon -> thalamus midbrain- mesencephalon -> midbrain hindbrain- metencephalon -> pons and cerebellum myelencephalon -> medulla
73
what folding causes the formation of the gut tube from the endoderm?
lateral folding and cranial caudal folding
74
what are the derivates of the endoderm?
foregut, midgut, hindgut, pharyngeal pouches, rathkes pouch
75
what are 3 derivatives of the mesoderm?
paraxial mesoderm, intermediate mesoderm, lateral plate mesoderm
76
what 2 layers of the lateral mesoderm?
splanchnic layer (moves with endoderm), somatic layer (moves with ectoderm)
77
what is derived from the intermediate mesoderm?
- Renal systems- kidneys, ureters | - Gonads and ductus systems
78
what is derived from the paraxial mesoderm?
somites ->Dermatomyotome | Sclerotome
79
what are the derivates of the 5 pharyngeal pouches from the endoderm?
1st pharyngeal pouch -Eustachian tube, middle ear cavity, mastoid antrum 2nd pharyngeal pouch -Palatine tonsils 3rd pharyngeal pouch -The dorsal wings develop into the inferior parathyroids glands. The ventral wings develop into thymus 4th pharyngeal pouch -Superior parathyroid glands 5th pharyngeal pouch -Obliterated by adulthood
80
what are the derivatives of the 4 pharyngeal clefts from the ectoderm?
1st pharyngeal cleft -> external auditory meatus | 2nd, 3rd and 4th pharyngeal clefts -> temporary cervical sinuses but are obliterated by adulthood
81
what structures made up from the foregut?
from the mouth to the proximal half of the duodenum
82
what structures are made up from the mid gut?
distal half of duodenum till the splenic flexure of the colon
83
what structures are made up from the hind gut?
descending colon to rectum
84
what is the derivative of the Truncus arteriosus (an embryonic structure? and how does this occure?
the truncus arterious become the ascending aorta and pulmonary trunk. The division of the truncus arteriosus is triggered by neural crest cell migration from the pharyngeal arche
85
what does the embryonic structure bulbis cordis develop into?
Right ventricle and smooth parts of left ventricle
86
what are the derivates of the primitive atria and the primitive ventricles?
primitive atria -> Trabeculated parts of the left and right atria primitive ventricle -> Majority of left ventricle
87
what are the derivatives of the left horn of the sinus venous and the right horn of the sinus venous (embryonic structures)?
Left horn of the sinus venosus -> coronary sinus Right horn of the sinus venosus -> Smooth part of the right atrium
88
what is the derivative of the Right common cardinal vein and right anterior cardinal vein?
superior vena cava
89
what is the derivative of the Ductus arteriosus ?
Ligamentum arteriosum
90
where do primodial germ cells originate from?
PGCs originate from the ectoderm
91
how is the notochord formed?
Mesodermal cells from the primitive node migrate towards the head end of the embryo to form a hollow tube = notochordal process → become a solid cylinder of cells = notochord.
92
what is the function of the notochord?
Notochord function = induction. The process by which one tissue stimulates the development of an adjacent unspecialised tissue. Notochord induces certain mesodermal cells to form vertebral bodies. Notochord forms the nucleus pulposus of the vertebral bodies.
93
what strcuctures do the ectoderm become?
CNS, skin
94
what structures do the mesoderm become?
bones, muscle and connective tissue
95
what structures do the endoderm become?
lining of the GIT and the airways
96
what are the 3 stages of translation?
INITIATION -RNA polymerase attaches to DNA and moves along till it reaches a promoter sequence, where it then unwinds the double helix ELONGATION -template strand is read 3' to 5', and RNA polymerase catalyses the formation of phosphdiester bonds between ribonucleotides to for mRNA TERMINATION -elongation continues until RNA polmerase reaches a stop sequence
97
what 3 processes occur to pre mRNA to become mature RNA?
5' capping polyadenylation splicing
98
what are the 3 stages of translation?
INITIATION -start codon (5'AUG) is recognised, so small 40s subunit can join and then the 60s subunit to complete initiation complex ELONGATION -ribosome has two tRNA binding sites P site which holds the peptide chain and the A site which accepts the tRNA. TERMINATION -One of the three stop codons enters the A site. No tRNA molecules bind to these codons, so the peptide and tRNA in the P site releases the polypeptide into the cytoplasm. The small and large subunits of the ribosome dissociate, ready for the next round of translation
99
Anatomy of endocervical canal?
ectocervix - end of vaginal canal external os - bottom of the neck of the womb internal os - top of the neck of the womb
100
what is the broad ligament of the uterus?
The broad ligament of the uterus is a double-layer fold of the peritoneum that attaches the lateral portions of the uterus to the lateral pelvic sidewalls.

medical sciences (11 decks)

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