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What arteries supply the corpora cavernosa starting at the abdominal aorta?
Abdominal aorta, common iliac artery, internal iliac artery, internal pudenal artery, dorsal and deep arteries of the penis
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What is the somatic nerve of the penis?
The dorsal nerve of the penis, a branch of the pudendal nerve
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What sensations do the pudendal nerve/ dorsal nerve of the penis carry?
Touch and temperature
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Where does the pudendal nerve originate?
Sacral plexus
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Parasympathetic innervation of the penis comes from the ....
Pelvic splanchnic nerves
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Sympathetic innervation of the penis comes from the ...
Sympathetic chains
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Two phases of ejaculation?
Emission and expulsion
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In ejaculation what is explusion?
Strong spasmodic contractions eject the semen
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How much semen is expelled?
2-5ml
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What is the composition of the semen?
60% seminal vesicle, 30% prostate gland, 5% bulbourethral glands, 5% testes
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What is the final part of the Fallopian tube called?
The infundibulum
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What are found at the end of the infudibulum and what do they do?
Fimbriae are found at the end of the infundibulum and aid in directing the ocytes to the tube
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Widest part of the fallopian tubes?
Ampulla
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Site of fertilisation?
Ampulla
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What processes can be completed when the sperm enters the cytoplasm of the oocyte?
Meiosis 2 (from metaphase 2 onwards) and thus oogenesis is complete
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What guides the sperm through the cervical canal and into the uterus?
Cervical mucous strands
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Why is a women most fertile just before and during ovulation?
Because the cervical mucous is very thin so sperm can move easily through
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What changes to the sperm occur during its passage through the female tract to allow it to penetrate the zona pellucida?
Capacitation (destabilization of acrosomal head) and activation of acrosomal/hydrolytic enzymes
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How long does capactiation take?
6-8hours
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3 layers sperm must penetrate for fertilization?
corona radiata, zona pellucida, oocyte cell membrane
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Final product of fertilisation?
diploid zygote
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How many cells does a morula have and at how many does does it result?
16 at 3days
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What does a zygote first cleave into?
blastomere (2 cells)
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What happens at 7 days after fertilisation?
Blastocyst breaks out of zona pellucida
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What is the name of the outer cell mass in the blastocyst (4-5days)?
trophoblast (becomes embryonic part of the placenta)
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In the second week what are the two layers of the embyroblast and what does they together form?
Epiblast and hypblast = bilaminar disc
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What side of the embryoblast does the yolk sac lie on?
hypoblast
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What day is implantation completed by?
10
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What layer of the trophoblast burrows into the endometrium and what do they create?
Syncytiotrophoblast burrows (implantation) forming lacunae
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Where and when does the primitive streak occur?
Week 3 on the epiblast (amniotic fluid, layer of embryoblast)
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What is the yolk sac?
Lies on the side of the hypoblast (layer of embryoblast) and provides nourishment early in development
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What develop from the lacunae and contribute oxygen, nutrient rich maternal blood to the umbilical cord?
Chorionic villi
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What does the umbilical cord carry back to the chorionic villi?
Deoxygenetated fetal blood
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How does the fetal blood supply differ from the adult blood supply?
- Fetal blood is deoxygenated arterial blood
- Maternal blood is oxygenated venous blood
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What anchors the fetus to the uterine wall?
Placenta
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What is parturition?
Process of childbirth
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What is the name given to cells that can develop into any type of body cell
totipotent
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What is the embryonic state?
First 8 weeks when all body systems are formed
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What results in identical twins?
Division of the morula or blastocyst
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At how many days has a blastocyst formed
5
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Are the blastocyst cells pluripotent or totipotent?
Pluripotent
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Name of the inner cell mass of the blastocyst?
Embryoblast
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What are the germ layers of the embryo?
Ectoderm, mesoderm, endoderm
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Ectoderm arises from what layer of the embryoblast and forms what?
Epiblast (amniotic space above) gives rise to cells inside the embryo
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How do the 3 germ layers form?
The cells of the epiblast move down the primitive streak pushing the hypoblast out of the way and forming new layers
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What is sirenomelia?
Insufficient mesoderm in the lower part of the body = mermaid, no kidneys
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What happens if the primitive streak cells are left behind?
Development of teratoma (tumour)
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What are tetratogens?
Tetratogens are agents that cause birth defects
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At what period is the embryo most sensitive to tetratogens?
3-8 weeks
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What structures develop from the mesonephric duct?
Epididymis, ductus deferens, seminal vesicles
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Fallopian tubes and uterus develop from what duct?
Paramesonephric duct
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What part of the germ cell layer do the testes and ovaries develop from?
The intermediate mesoderm (part of the mesoderm cell layer)
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Where are germ cells created and when do they migrate to the gonads?
Yolk sac, migrate 3 weeks after fertilization
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At germ cell migration to the gonads (3 weeks after fertilization) is the intermediate mesoderm testes/ovaries or indifferent?
Indifferent (can be either)
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Is the default pathway male or female?
Female
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What enables the intermediate mesoderm to turn into a testes?
The sex-determining region of the Y-chromosome (SRY)
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What does the genital ridge develop into?
The gonads
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What is another name for the mesonephric ducts?
Wolffian ducts
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If the embryo is female the absence of androgens and Mullerian inhibiting substance causes what?
The disappearance of the Wolffian ducts
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How does the uterus develop?
The Mullerian ducts fuse and develop a large lumen
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Do the testes begin superior or inferior?
Superior
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What development makes the epididymis become inferior to the ducuts deferens and seminal vesicles?
The testes descent into the scrotum
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Why do the Mullerian ducts disappear?
Presence of Mullerian Inhibiting Substance (MIS/ AMH)
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3 division of the genitalia?
genital tubercle, genital fold, genital swelling
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What do the genitalia become in females?
Vagina, vuvla, clitoris
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Female pathway:
genital tubercle
genital fold
genital swelling
- Female pathway:
- genital tubercle - clitoris
- genital fold - labia minora
- genital swelling - labia majora
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What must be present for the male external genitalia to develop?
Androgens
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Male pathway:
genital tubercle
genital fold
genital swelling
- Male pathway:
- genital tubercle - glans penis
- genital fold - body of penis
- genital swelling - scrotum
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