Sperm transport

 

Before the semen is deposited in the vagina in the normal process of copulation, it must transverse the whole of the male duct from the epididymis to the fossa terminalis of the urethra shortly before its ejaculation outside into the female tract. In the epididymis it is stored in the caudal portion. There it is assisted in nutrition by epithelia which have stereocilia. At emission, the sperm cells pass from the epididymis into the vas deferens which lacks stereocilia at its distal portion and at the ampulla of the vas which is placed proximally. Transport is by peristalitic movement in the vas. The ampullary epithelium has numerous foldings and act as a secondary store of sperm and produces certain amounts of secretions. In the seminal vesicle secretions are produced such as fructose, phosphorylcholine and globulins. From urethra to the ejaculatory duct, the epithelium of the urethra is lined with transitional epithelium and the secretions from accessory glands (such as the prostatic secretions, prostatic utricle and bulbourethral glands reach its lumen and aid the nutrition of the sperm which it transverses.

The secretions of the prostate gland is alkaline and helps to neutralize the acid medium of the traversing sperm. The acid becomes accumulated as a result of acid metabolites formed during the storage of sperm at the epididymis. Other secretions in the prostate include phosphates, citrates and calcium. The fructose from the seminal vesicle is utilized by the sperm and it is broken down by the mitochondrial enzymes of the sperm cells.

In order to reach the destination which is in this case the ampulla of the oviduct for fertilization, it has to be transported in two recognized phases.

1. Rapid transport phase. This is the phase in which sperm is transported very rapidly into the peritoneal cavity through the fallopian tube a few minute after ejaculation into the vagina

2. The second phase is the slow transit phase. It is believed that the sperm in this phase are responsible for the fertilization of egg. The sperm cells are released from the coagulum formed in the vagina near the eternal os of the cervix into the uterine cavity where they are exposed to glycoprotein in the uterine cavity which is thought to aid their capacitation. They then move to the junctura where they are further exposed. At the isthmus, they become trapped in the ampullary-isthmic junction which is both a functional and anatomical sphincteric region. This junction allows only the very active sperm cells to penetrate so that the ampulla has very little but very active sperm cells which are destined to fertilize the egg. It is therefore believed that the ampullary isthmic junction acts as a sieve to allow only active sperm cells into the ampulla for fertilization. Rapid transport of the spermatozoa through the female genital tract has been shown to be under the endocrine control of the dominant follicle. This helps to ensure that spermatozoa are accumulated at the site of fertilization. Sperm cells acquire glycoprotein coasts which allow them to escape the immunological  recognition mechanism of the female body and also to prevent leucocytic invasion. In certain conditions in which sperm antibody titers are high, this recognition camouflage breaks down for reasons which are still not very understood.


Sperm transport: Oviduct is responsible for egg sperm and embryo transports. Its sperm transport has two phases. The fast and the slow one. The fast phase allows the sperm to reach the ampulla or even peritoneum in seconds. The second and slow phase takes several minutes.

 

 

 

 

 

 

 

 

 

 

Introduction
Cell Biology
Embryology
Histology
Gross Anatomy
Lymphatic drainage

Organ integration
Clinical anatomy

Quiz

Dissector
Physiology

Biochemistry

Pharmacology

Chemical Pathology

Anatomical Pathology

Imaging

Medicine

Surgery

Main Subject Course Links

eAnatomy eAnesthesia eBiochemistry eChemical pathology eCommunity Health
eDermatology eENT eGynecology eHematology eImaging
eMedicine eMedical microbiology eObstetrics eOphthalmology ePathology
ePediatrics ePharmacology ePhysiology ePsychiatry    eSurgery/eOrthopedics
eLab eOSCE eProcedures eInvestigations eSchool/Videopage
eOrgans eLocator Anatomy Museum eDissector eFractures/Dissect-it-yourself
All diseases eClerking eTreatment eDoctor ePatient

 

Electronic School of Medicine
Creator: Oluwole Ogunranti