4.1 testis and scrotum (workbook) Flashcards
what does the male reproductive system consist of?
paired testes
duct system
accessory sex glands
penis
what is the function of the paired testes?
produce spermatozoa (sperms)
what do the paired testes contain?
cells that produce the sex hormones
Leydig + Sertoli cells - mainly Leydig
what is the function of the duct system within the male repro system?
transport spermatozoa to urethra
what is the function of the accessory sex glands within the reproductive system?
supply the fluid components to the semen
what is the human testis?
a compound tubular gland
what encloses the human testis?
a thick fibrous capsule - tunica albuginea
posteriorly, what does the tunica albuginea form? function?
forms the mediastinum testis that contains many interconnected channels which provide passageways for the sperms to enter the duct system
deep to the tunica albuginea, what is found?
strong CT septa extend into the testis, dividing it into about 250 pyramid-shaped lobules
what does each lobule within the testis contain? function?
between 1-4 highly convoluted seminiferous tubules, in which spermatozoa are produced
what are the testes contained within?
the scrotal sac
what does the scrotum consist of?
a layer of skin and superficial fascia
what does the superficial fascia of the scrotum contain?
the dartos muscle
underneath the thick tunica albuginea, what is evident?
seminiferous tubules
what is each seminiferous tubule surrounded by?
a layer of connective tissue with flattened myofibroblasts and an inner basement membrane
what are the seminiferous tubules lined by?
a complex stratified epithelium: seminiferous epithelium
what does the seminiferous epithelium lining seminiferous tubules contain?
2 types of cells: Sertoli cells (supporting cells) spermatogenic cells (germ cells)
where are Sertoli cells found?
fixed to the basement of the seminiferous tubules (within the stratified epithelium)
how are numbers of Sertoli cells different from spermatogenic cells?
Sertoli cells are far less numerous than spermatogenic cells
what do the cytoplasm of each Sertoli cells form?
an elaborate system of processes that extend upward to the luminal surface, surround the spermatogenic cells and fill all the spaces between them
what does the apical region of each Sertoli cell contain?
complicated recesses into which the heads of sperms appear to be embedded
how are spermatogenic cells arranged?
in rows between and around the Sertoli cells
what are the most primitive spermatogenic cells?
the spermatogonia
where are the spermatogonia found?
rests on the basement membrane of seminiferous epithelium
later stages located successively higher levels in epithelium
where do primary spermatocytes lie?
adjacent to spermatogonia, but nearer the lumen
what do the primary spermatocytes have nuclei like?
the nuclei have variable appearances that represent the stages of the first meiotic division
where are secondary spermatocytes seen?
rarely seen in the seminiferous epithelium, because of their short 1/2 life
what do secondary spermatocytes form?
divide rapidly (secondary meiotic division - post fertilisation) to form spermatids
how do spermatids appear?
lightly stained round nucleus, located nearer the lumen of the seminiferous tubule
what do spermatids mature into?
spermatozoa
how do spermatozoa appear?
deeply staining heads of which appear to be embedded in cytoplasm of the Sertoli cells and their tails hang into the lumen of the seminiferous tubule
describe the development stages of spermatogenic cells (germ cells)
spermatogenic cells (germ): spermatogonia (primitive) --> primary spermatocytes --> secondary spermatocytes -- (secondary meiotic division) --> spermatids -- (mature) --> spermatozoa
what is spermatogenesis?
the process by which spermatogenic cells (germ) undergo cell proliferation and maturation and are transformed over a period of time into spermatozoa
between the seminiferous tubules, what is there?
loose CT containing interstitial (Leydig) cells
where are Leydig cells seen?
in isolated clusters / in rolls along small blood vessels
Sertoli in BM of seminiferous tubules
how do Leydig cells appear?
have large spherical nuclei with eosinophilic sections (stains red)
what do the nuclei of Leydig cells contain?
small amounts of PERIPHERALLY located chromatin and 1 / 2 prominent NUCLEOLI
where does spermatogenesis occur?
in seminiferous tubules
between and around Sertoli cells
where does steroidogenesis occur?
in Leydig cells
how is spermatogenesis and steroidogenesis linked?
occur in separate histological compartments within testis, but compartments are functionally and physiologically interaction
(Leydig cells produce testosterone, which diffuses into seminiferous tubules, for Sertoli cells to produce enzymes?)
