Conception Flashcards
What is the tissue attenuation coefficient?
The absorption ability of a tissue
What scale is used to calibrate the grey scale on a CT scanner?
The Hounsfield unit scale
Positives about CT scanning
Quick
Lots of info
Multiple regions
Can guide procedures
Positives about X- ray scanning
Low radiation
Quick
Cheap
Accessible
Positives about fluoroscopy
Multiple images
Can see function
Therapeutic procedures
Positives about ultrasound
No radiation Can see BF Quick Accessible Guides procedures
Positives about MRI scanning
Multiple image planes
No radiation
Lots of soft tissue info
Negatives about CT scanning
Lots of radiation
P needs to be still
Negatives about X-ray scanning
Some radiation
2D
Hard to interpret
Negatives about fluoroscopy
Radiation
Specialised
2D
Needs contrast
Negatives about ultrasound scanning
Specialised
Not for all tissues
Not recorded
Negatives about MRI scanning
Specialised
Limited availability
Which scanning techniques produce 3D images?
CT
Difference between fluoroscopy and X-ray?
Fluoroscopy is a video X-ray and requires contrast
What is T1 and T2 in MRI scans?
Flip and spin - T1 is fat and T2 is water
What are MRI scans used to image?
Soft tissue - muscle, nerves, organs
How does nuclear medicine work?
Radioactive tracer goes to metabolically active areas and emits gamma rays (cancer staging)
What is the outside of the Zygote called?
Zona Pellucida
What is a zygote called when it has divided many times?
Morula
What are the three types of differentiated cells in a blastocyst?
Trophoblasts, embryoblasts (epiblasts) and hypoblasts
What process forms the trilaminar disk?
Gastrulation
What starts the formation of the middle layer of the trilaminar disk?
The primitive streak
What are the three germ layers called?
Ectoderm, mesoderm and endoderm
What does the ectoderm go on to form?
Nervous system and skin
What does the mesoderm go on to form?
Connective tissue, bone, muscle, urogenital, pleura and peritoneum
What does the endoderm go on to form?
Lining of internal organs - GI and airways
What are the three precursors to the uro-genital system in an embryo?
Pronephros
Mesonephros
Metanephros
What does the pronephros give rise to?
Replaced by mesonephros
What does the mesonephros give rise to?
Gonad and adrenal glands
What does the metanephros give rise to?
Kidneys
What ducts form the internal reproductive organs in males and females?
Females - paramesonephric (mullerian)
Males - mesonephric (Wolffian)
What do to primordial germ cells give rise to in both males and females?
Males - spermatogonia
Females - primordial follicle then oogonia then oocytes
What do steroidogenic and supporting cells give rise to in males?
Steroidogenic - leydig
Supporting - sertoli
What do steroidogenic and supporting cells give rise to in females?
Steroidogenic - theca
Supporting - granulosa
What three factors determine sex differentiation?
SRY, TDF and MID
How is the vagina formed from the paramesonephric ducts?
They fuse
What do the gonadal cords become?
The seminiferous cords
What do supporting cells come from in males?
Coelomic epithelial cells
How do the testes get into the scrotum?
The gubernaculum pulls them from the intra-abdominal site
What do the gonadal cords become?
Seminiferous cords
What are the 4 main initial steps of male development?
- Mesenchymal cells turn into the interstitial cells of leydig cells
- Testosterone and androstendione production
- Somatic support cells turn into pre-sertoli cells
- Anti-mullarian hormone makes mullerian ducts degenerate
What does testosterone control the formation of?
Penis Scrotum Prostate Epididymis Ductus deferens Seminal vesicles Brain differentiation
What are the first 5 steps of female differentiation?
- Wolffian ducts degenerate and the mullerian ducts form
- External genitalia form - clitoris and labia
- Supporting cells turn into granulosa cells
- Steroidogenic cells turn into theca cells
- Germ cells begin 1st stage of meiosis
What do the mullerian ducts form?
Oviducts
Uterus
Cervix
Upper vagina
What hormone is measured in a pregnancy test?
Human Chorionic Gonadotropin
What is the mesovarium?
Part of the broad ligament that suspends the ovaries
What is the mesosalpinx?
A ligament which attaches the uterine tube to the broad ligament
What is the ligament of the ovary?
Attaches the ovary to the uterus
What is the suspensory ligament of the ovary?
The highest part of the broad ligament
What does the round ligament do?
Pulls the uterus forward and attaches to the perineum
What are the functions of the pelvis? (5)
- Weight bearing
- Weight transfer (walking)
- Muscle attachment
- Contains pelvic viscera and inf abdominal viscera
- Supports abdominopelvic viscera
What is the pelvic floor between?
The pelvic cavity and the perineum
What are the features of the male pelvis? (3)
- Narrow and shallow pelvic cavity
- Small angle of public arch
- Narrow inf pelvic aperture
(Opposite for female)
What is the process of ejaculation? (7 steps)
- Made in testes
- Stored in epididymis
- Travels via ductus deferens
- Mixes with semen from seminal glands
- Prostate fluid added from prostate
- Alkaline mucus added from bulbo-urethral gland
- Out of urethra
What does ‘some damn Englishman called it the testes’ stand for?
Skin Dartos fascia External spermatic fascia Cremaster Internal spermatic fascia Tunica vaginalis Tunica albuginea
What is autocrine?
Cell targets itself
What is paracrine?
Cell targets neighbor
What is endocrine?
Cell targets distant cell through blood
What happens in the G1 phase of the cell cycle?
Contents duplicated
What happens in the S phase of the cell cycle?
Chromosomes duplicated
What happens in the G2 phase of the cell cycle?
Chromosomes are checked and repairs are made
What is checked at the G1 phase of the cell cycle?
Cell size
Nutrients
Growth factors
DNA damage
What is checked at the G2 phase of the cell cycle?
Cell size
DNA replication
What are the 3 classes of hormones?
Steroid
Peptide
Amino acid derived
What is negative feedback?
High level of hormone inhibits more being released
What is positive feedback?
High level of hormone causes more to be released
Describe the hypothalamo-pituitart axis
Hypothalamus
Ant pituitary gland
3rd endocrine gland
Target endocrine hormone
What happens to GnRH in the follicular phase of the menstral cycle?
It steadily increases
What happens to FSH in the follicular phase of the menstral cycle?
Starts to increase then steadily decreases until 14 days where there is a small spike
What happens to LH in the follicular phase of the menstral cycle?
Stays the same until 14 days where there is a big spike (ovulation)
