Lecture 5.2: Coitus & Fertilisation Flashcards
What is the Definition of Sexual Reproduction?
Formation of a unique individual from the gametes (spermatazoon and oocyte) of two other individuals
How many days does spermatogonia to mature spermatozoa take? In what parts of the male reproductive system does this occur?
- c. 74 days
- ~50 days in seminiferous tubules
- ~12-26 days in epididymis
How many spermatozoa made every second?
1000
What are the 3 parts of the epididymis?
- Head (caput)
- Body (corpus)
- Tail (cauda)
What happens in the caput of the epididymis? (2)
- Fluid reabsorption
- Sperm chromatin compaction
What happens in the corpus of the epididymis? (5)
- Protein synthesis
- Vesicles secretion
- Acquisition of progressive sperm motility
- Sperm chromatin compaction
- Defence response
What happens in the cauda of the epididymis? (4)
- Sperm storage
- Sperm chromatin compaction
- Defence response
- Sperm quality control
Pathway of sperm transport to the female reproductive system?
- Through epididymis
- Into urethra (emission)
- Out of the male body (ejaculation)
- Through the female tract
What are the Phases of Sexual Response in Males? (4)
- Excitement phase (erection)
- Plateau phase
- Orgasmic phase (emission and ejaculation)
- Resolution phase (+/- refractory period)
What are the Phases of Sexual Response in Females? (5)
- Excitement phase (blood engorgement and erection:
clitoris, vaginal mucosa, breast and nipples) - Plateau phase
- Glandular activity
- +/- orgasm
- No physiological refractory period
What is Tumescence?
The quality of being swollen, or a swollen part of the body, especially caused by sexual excitement
What Haemodynamic Changes causing Tumescence
- Inhibition of sympathetic arterial vasoconstrictor
nerves - Activation of PNS
- Activation of nonadrenergic, noncholinergic,
autonomic nerves to arteries, releasing NO
How does NO cause smooth muscle relaxation and vasodialation? (5 Steps)
- Endothelial cells stimulated to release NO
- NO also released directly from nerves
- NO diffuses into vascular smooth muscle
- Decreased Ca2+
- Relaxation of smooth muscle (vasodilation)
What are some causes of erectile dysfunction?
- Psychological (descending inhibition of spinal reflexes)
- Tears in fibrous tissue of corpora cavernosa
- Vascular (arterial and venous)
- Drugs
- Factors Blocking NO: alcohol, anti-hypertensives,
diabetes
Viagra causes an erection, what is its MOA?
- Normally, the PDE (phosphodiesterase inhibitors)
breaks down the cGMP into molecules that cannot
cause erections - By inhibiting the breakdown of cGMP, Viagra leads to
more cGMP - PDEs cause reductions in the needed chemical in the
penis, and Viagra blocks the PDE to prevent this from
happening
How does Emission of Semen occur?
- Movement of ejaculate into prostatic urethra (leakage)
- Under sympathetic control
- Vas deferens peristalsis
What gland add secretions to semen? (3)
- Prostate
- Seminal Vesicle
- Bulbourethral Glands (Cowper’s Glands)
What percentage of Glandular Components of Semen come from Seminal Vesicles?
60% volume