Lecture 9 - Getting Pregnant, Sex And Fertilisation Flashcards
Where is sperm produced?
Seminferous tubules by germ cells
Where do spermatozoa travel to following the Seminferous tubules?
Epididymis
Vas deferens
Ejaculatory duct
Prostatic urethra
Membranous urethra
Spongy urethra
External urethral meatus
Where do spermatozoa first start to mature once produced?
What is needed to support this?
Epididymis
Androgens
What are the 2 main components of semen?
Spermatozoa + Seminal plasma
Where is seminal plasma produced?
Accessory glands of male repro tract
What are the general functions of the seminal plasma?
Transport medium for sperm
Nutrition to sperm
What are the 3 main accessory glands that produce seminal plasma?
Seminal vesicles
Prostate gland
Bulbourethral glands
Which of the accessory glands produce the majority of the volume of seminal plasma?
Seminal vesicles
Describe the composition of the seminal plasma made by the seminal vesicles:
Acidic?
Contents?
Alkaline (neutralises acidic male urethra and female repro tract)
Fructose (energy)
Prostaglandins (move sperm along female tract)
Clotting factors (needed to move sperm)
Describe the composition of the seminal plasma made by the prostate gland:
Acidic?
Contents?
Milky and slightly acidic
Contains proteolytic enzymes (breaks down clotting proteins re-liquefying semen
Citric acid and acid phosphatase
Describe the composition of the seminal plasma made by the bulbourethral glands:
Acidic?
Contents?
Very small volume
Alkaline
Mucous that lubricates the end of the penis and urethral lining
What is the reference volume of semen?
Between 1.4 to 1.7ml
What percentage of spermatozoa need to look normal?
4%
What percentage of sperm need to be moving?
38 - 42%
Where does fertilisation take place?
Ampulla
What are the 4 stages of the human sexual response?
Excitement phase
Plateau phase
Orgasm phase
Resolution phase
What occurs in the excitement phase of the sexual response?
Psychological or somatogenic stimuli (touching)
What changes occur in the orgasm phase and then resolution phase?
Orgasm phase = lots of heamodynamic changes
Resolution phase = return to normal haeodynamics
Contains refractory period
What is the refractory period?
The time period in men where they cannot orgasm
What is Point and Shoot used to remember?
Point (erection) = parasympathetic
Shoot (ejaculation) = sympathetics
What are the important efferent nerves in obtaining an erection?
Pudendal nerve
Pelvic nerve
Somatic and autonomic efferent
What are the spinal nerve roots of th pundenal nerve?
S2 - S4
What part of the penis receives an increased blood flow to achieve an erection?
Corpus cavernosum
What it’s the blood supply like in the flaccid penis?
Arterio-venous anastomoses allows blood to bypass the corpus cavernosum
The helicine arteries stay coiled
How does the penis change during erection, blood supply?
Smooth muscle in helicine areties relaxes, straightens and dilates allowing blood into corpus cavernosum
Bulbspongiosus compresses venous plexus keeping more blood in penis
What neurophysiological changes occur during an erection?
What substance is produced?
Inhibiton of sympathetic arterial vasoconstrictor nerves
Nitrous Oxide produced
What is the effect of Nitrous oxide on blood vessels?
Potent vasodilator
What is the process to producing NO to cause vasodilation?
Post ganglionic make ACh
ACh binds to M3 receptors
Levels of NO rise
Diffuses into vascular smooth muscle causing relation
What can causes erectile dysfunction>
Psychological
Vascular (Cardiovascular disease, diabetes Mellitus)
Anatomical
Neurogenic - peripheral neuropathy Diabetes , spinal cord lesion, multiple sclerosis)
Hormonal
Drugs
How does viagra work to treat Erectile dysfunction?
Is a phosphodiesterase inhibitor preventing break down of cGMP so the effects of NO last longer (vasodilation and erection)
What are the 2 parts of of ejaculation?
Emission
Expulsion
What occurs in the emission stage of ejaculation?
Deposition of seminal plasma into the prostatic urethra
What occurs in the expulsion stage in ejaculation?
Expulsion of semen through the urethra and out the urethral meatus
What is the name of the sphincter joining the bladder to the urethra?
Internal Urethral Sphincter
What happens to the internal urethral sphincter ini ejaculation?
Why’s this important?
Closes during ejaculation
Prevents retrograde ejaculation (stops Ejaculate entering bladder)
What hormone is responsible for making the cervical mucus thin and stretchy?
What stage of the menstrual cycle is this relevant to?
Oestrogen
Thin and Stretchy around ovulation
What hormone is responsible for making the cervical mucus thick and sticky?
What stage of the menstrual cycle is this relevant to?
Progesterone
Produced in the luteal phase and is still present but decreases as menstruation occurs
What are the changes that occur during teh female sexual response?
Vaginal lubrication occurs
Clitoris enlarges
Uterus contractions
Rhythmic contraction in orgamsic platform
What part of the femal repro tract is sperm deposited?
Cervix
What is capacitation?
Further maturation of the sperm when its in the female reproductive tract
What changes occur to the sperm in capacitation?
Sperm loses outer layer of its head so can interact with egg
Tail movement more whip like
What is the acrosome reaction?
When the head of the sperm produces enzymes which break down the outer layer of the egg called the zona pellucida
What is the layer surrounding the outside of the zona pellucida that sperm must push through?
Corona radiata
What happens once a sperm manages to fuse with the plasma membrane of the oocyte leading to fertilisation?
Cortical reaction
What is the cortical reaction?
The process that occurs once a single sperm has fused with the egg to block other sperm from accessing the egg preventing polyspermy
What stage of the cell cycle is resumed for the oocyte once fertilisation has occured?
Meiosis II
What is the Morula?
What forms once fertilisation occurs, all cells totipotent, contains 16 cells before it becomes the blastocyst
What stage of development is an embryo when its implanted in Assisted Reproductive Technolgy?
Morula
What’s the benefit of Pre-implantation Genetic diagnosis?
Ensure no chromosomal abnormalities
What needs to happen before the blastocyst can implant in the uterine wall?
Zona pellucida needs to break down so the blastocyst can hatch from the zona pellucida
What is the order of the accessory glands in the male reproductive tract from most proximal (closest to the Seminiferous tubules) to most distal (closest to the external urethral meatus)?
Seminal vesicles
Prostate gland
Bulbourethral gland
