Microanatomy 1 Flashcards
what are the four main structures of the male reproductive system
- testes
- reproductive ducts
3, accessory glands
4, supporting structures
what are the reproductive ducts in the male reproductive system
- epididymis
- vas deferens
- ejaculatory duct
- urethra
what are the accessory glands in the male reproductive system
- seminal vesicles
- prostate gland
- bulbourethral glands
what are the supporting structures in the male reproductive system
- scrotum
- penis
- spermatic cords
where are the testes located
- they are located in the scrotum
what are the testes surrounded by
- they are surrounded by the peritoneal serosa with which they have migrated from the abdomen during development
- under the visceral part of the serosa there is a connective tissue that forms a fibrocollagneous capsule this protects it and via septa that enters into the body of the testis, divides it into lobules
what does the peritoneal serosa allow the testes to do
- it allows them to move freely in the scrotum
where are spermatoza produced
- they are produced in the germinal epithelium of the seminiferous tubules
describe the structure of the seminiferous tubules
- the seminiferous tubules are conducted into a network of channels - the retentions testis and then into efferent ductules before they enter the epididymis
- this is a tightly coiled muscular tube that is continuous with the ductus(vas) deferens
what is the Amin function of the testes
- production of male gametes
2. secretion of male sex hormones such as testosterone
what is the process of production of male gametes caused by
- spermatogenesis
- there development into motile spermatozoa is called spermiogensis
what is the difference between spermatogenesis and spermiogensis
- sperimogensis is there development into motile spermatozoa
- spermatogenesis is the production of male gametes
where does spermiogensis occur
epididymis
where are leydig cells found
they are found between the seminiferous tubules in the interstitial supporting tissue along with a rich capillary and lymph vessel network
what triggers testosterone secretion
LH leutenising hormone
- this can sometimes be referred to as interstitial cell stimulating hormone
what cells produce testosterone in males
Leydig cells
when do spermatogenesis and spermiogensis begin
- it begins at puberty and continues through adult life
what do the seminiferous tubules contain before puberty
- contains only the primitive germ cells called spermatogonia
- Sertoli cells
what do the seminiferous tubules contain after puberty
- at onset of puberty the testes secrete large amounts of testosterone
- this causes growth of the tests
- maturation of the seminiferous tubules and gamete production
- development of male secondary sexual characteristics
what does testosterone cause to happen
- this causes growth of the tests
- maturation of the seminiferous tubules and gamete production
- development of male secondary sexual characteristics
where are the sertoli cells
- they are on the basement membrane
- they completely enclose the spermatogenic cells and support and nourish them
what is the function of sertolis cells
- secretion of factors that regulate spermtogenssi and spermiogensis and leydig cell function
- secretion of tubular fluid and pahocytosis of discarded spermatid cytoplasm
- upon stimulation by pituitary FSH they also secrete ABP t
- they secrete inhibin
what does inhibin do
regulate pituitary hormone production
describe how Sertoli cells form blood testes barrier
- tight junctional complexes between Sertoli cells divide the epithelium into basal and adluminal compartments
- this forms a blood-testis barrier which isolates the antigenically distinct gametes from the immune system
what do tight junctional complexes between Sertoli cells do
divides the epithelium into basal and adluminal
what happens in spermatogenesis
Spermatogonia undergo mitosis to…
- maintain a pool of germ cells
- to form primary spermatocytes
Describe how spermatids form
- each primary spermatocyte undergoes the first meiosis to form two secondary spermatocytes
- each secondary spermatocyte undergoes a second meiosis to form two spermatids
describe what spermatozoa form from
spermatogonia type A - mitosis spermatogonia type B - mitosis pirmary spermatocytes - migration to adluminal compartment and undergo a 1st meiotic division secondary spermatocytes - 2nd meiotic division spermatids serpmatozoa
where do spermatogenesis and spermiogensis occur
- they occur in waves along the seminiferous tubule
what is spermiogensis
- this is the process through which the male haploid gametes, spermatids, are transformed into mature spermatozoa
describe the process of spermiogensis
- the golf apparatus makes a large vesicle that accumulates hydrolytic enzymes
- this becomes attached to one pole of elongating nucleus forming the acrosomal head cap, the acrosome plays an important role in fertilisation
- centrioles migrate to the opposite end and one elongates giving rise to the axoneme in the centre of the flagellum, this has a similar structure to cilia
- nine course fibrils surround the elongating flagellum, in the tail fibre ribs arrange circumferentially around it
5, cytoplasm migrates around the first part of the flagellum where mitochondria also concentrate - mitochondrial form a helical arrangement around the flagellum in the mid piece providing energy for movement, excess cytoplasm is phagocytksed by the enveloping Sertoli cell before ether spermatid is released into the lumen
- it will not develop motility until its maturation in the epididymis
when does the sperm develop motility
- it will not develop motility until its maturation in the epididymis
describe the structure of the epididymis
- comprises of a head, body and tail
Head and body
- the smooth muscle surrounding this tube produces a slow rhythmic motion that gently moves the spermatozoa towards the vas defers
- in the tail portion, the sympathetic nervous system activity will produce strong contractions during ejaculation
what is the function of the epididymis
- accumulation, storage and maturation of spermatozoa
describe the epithelium of the epididymis
- there is pseudo stratified columnar epithelium
- long microvilli which are visible under light microscope
what does the long mcirovili do in the epididymis
- they help absorb excess fluid that accompanies the spermatozoa from the testis
what is the role of the vas deferns
- it is responsible for transporting the spermatozoa from the epididymis to the urethra
describe the epithelium of the vas defers
- it has psudostrafieid columnar epithelium
- the mucosa is folded which allows expansion during ejaculation when sympathetic neural activity causes strong peristaltic contractions
- has a thick muscular wall this makes it palpable in the spermatic cord
- surrounded by an adventitia
what is an adventitia
- this is an outer relatively loose fibrocollagneous connective tissue
what do the male accessory organs consist of
- seminal vesicles
- prostate glands
what makes up the seminal fluid
- the seminal vesicles and prostate gland make up the secretions which make up the seminal fluid
what does the bulbourethral glands make
- they make a mucosa like product that lubrciates the penile urethra during arousal
describe the structure of the prostate gland
- fibromsucualr structure
- composed of tubuloalveolar glands that surround the bladder neck and first part of the urethra - this is known as the prostatic utrethra
- surrounded by a thin fibrocollagenous capsule
- ## at the atneriroa nd apical aspect there is the anterior fibromuscular storm - this consists of fibrcolalgenous tissue with muscle fibres
what are the zones of the prostate
- central zone
- transitional zone
- peripheral zone
what are the 3 zones of the prostate surrounding
- central zone - surrounds the ejaculatory ducts
- transitional zone - surrounds the first part of the prostatic urethra
- peripheral zone - has the majority of glands
why are the divisions of the prostate gland clinically important
- because in almost all cases of benign prostatic hyperplasia occur in the transitional zone
- and almost all cases of carcinoma of the prostate arise in the peripheral zone
what does the highly folded epithelium allow the prostate Gand to do
- it allows them to expand and store secretions
describe the structure of penis
- it has three columns of erectile tissue in the centre that contain many vascular spaces
- two columns located dorsally are the corpora cavernous or the penis
- the ventral volume surrounds the penile urethra and is called the corpus spongiosum
- these are surrounded by firboelastic tissue, the CCP with a relatively thick layer
- the loose hypodermic allows the skin of the penis to move over these structures
