Male Reproductive System Flashcards
First Page
What is the epithelium of seminiferous tubules?
4-8 layers of germinal epithelium with spermatogneic cells and sertoli cells
Where are leydig cells located in the seminiferous tubules? What are their defining characteristics? What do they produce?
Located in the interstitial areas between seminiferous tubules. They are acidophilic with large central nuclei and abundant smooth ER and lipid droplets. Produce and secrete testosterone from cholesterol esters
What stimulates testosterone secretion? What method of secretion? (endocrine or exocrine?)
Stimulated by lutenizing hormone from the pituitary gland. Endocrine secretion
What is a sertoli cell? What is is its key features?
Sertoli cell is a support cell for spermatogenic cells. Tall columnar cell, pale, oval, indented nucleus with large nucleolus. Prominant organelles
Why do sertoli cells form junctions, and what do they form junction with?
Forms junctions (zona occludens) with other sertoli cells for dividing seminiferous tubule into a basal and adluminal compartment - blood testes barrier
What can a sertoli cell do?
Phagocytose excess cytoplasm of maturing spermatids,
secrete fructose rich fluid that transports speratozoa through sem. tubules.
Synthesize and secrete Androgen-binding protein which concentrates testosterone
Synthesize and secrete inhibin - inhibits synthesis and release of FSH by anterior pituitary
Synth. and secrete testicular transferrin - accepts iron from serum transferrin and gives to maturing gamates
What kind of receptors do sertoli cells have?
FSH receptors on plasma membrane
What is the purpose of the blood-testis barrier?
Protecting developing sperm from immune system
When does sperm production begin? what is present before?
Puberty, spermategonia present before
What are the three phases of sperm development?
Spermatogonial (spermatogenesis), spermatocyte (meiosis), and spermatid (spermiogenesis)
Intercellular bridges
What are the wave-like sequences
Are spermatogonia diploid or haploid? How many chromosomes?
Diploid, 46 chromosomes
What is the difference between pale and dark type A spermatogonia
Pale type are mitotically active and give rise to more Ap or B cells. Dark cells are mitotically inactive and are essentially stored in the G0 phase - can resume mitosis to produce pale A cells.
What is special about Dark type A cells in terms of cancer?
They are chemo/radiation resistant
What is a Type B spermatogonia?
Type B undergo mitosis and are precursor to primary spermatocyte.
What is characteristic of type B spermatogonia in terms of chromatin?
Stays in large clumps arlong nuclear envolope with a central nucleolus
List in order the cell development of sperm from Ad to Spermatozoa
Ad -> Ap - >B - > Secondary spermotocyte - > spermatids - > spermatozoa
When do primary spermatocytes migrate to adluminal compartment?
Once they have formed duplicate chromosomes and have 2x 2n DNA
What forms while primary spermatocytes migrate?
Form zonula occludens with sertoli cells
How many sperm does each spermatogonia form?
4 sperm
How many cells divisions are in spermatogenesis? How many DNA replications?
2 cell divisions, 1 DNA replication
Describe the meiosis phase of spermatogenesis (I and II)
Primary spermatocytes reduce from diploid to haploid as one chromosome with 2 chromatids divides into each 2 degree spermatocyte.
2nd division results in 2 spermatids with no replication, such that each spermatid contains a single stranded chromatid
What are spermatids?
Haploid cells with only 1N DNA
Where are spermatids formed?
Near the lumen of the seminiferous tubule
What are the features of a spermatid cell?
Regions of condensed chromatin, very condensed nuclei - centriole pair, mitochondria, free ribosomes, sER and well developed Golgi
How long does Meiosis I last? Where does it occur?
22 days in primary spermatocyte
What are the five stages of Meiosis I?
Leptotene, zygotene, pachytene, diplotene, diakinesis
Describe the basics of each stage of prophase in meiosis I
Leptotene - chromatins condense
Zygotene - homologous chromosomes form synaptonemal complex allowing for crossing-over
Pachytene - chromatids are visible and crossing-over begins
Diplotene - Chromosome condenses further and chiasmata are evident
Diakinesis - nucleolus disappears and nuclear envelope disintegrates
What is the most similar phase between mitosis and meiosis I?
Metaphase
What are the differences between anaphase and telophase of mitosis and meiosis I
Chromosomes do not split! Instead, paired chromatids stay together
What is the biggest difference between Meiosis II and mitosis?
No DNA synthesis
What are the four phases of cytodifferentiation of spermatids to spermatozoa?
Golgi phase, cap phase, acrosomal phase, maturation phase
Golgi phase
Golgi phase
Cap phase
Cap phase
What condenses in the acrosomal phase? How is this accomplished?
Nucleus condenses and flattens towards head. This is accomplished by a temporary cylinder of microtubules called the manchette which aids in replacing HISTONES with PROTAMINES. Prot. 1 and 2 allow for a high order of chromatin packaging. Mitochondria aggregate around proximal flagellum - whole process makes sperm efficient for fertilization
Maturation phase
Maturation phase
Maturation phase
Maturation phase
***Maturation phase
Maturation phase
Maturation phase
Describe flow from seminiferous tubules to ductus deferens. Include epithelium transitions.
Tubuli recti transitions from sertoli cells to simple cuboidal epithlium with microvilli and single cilium.
Rete testis - simple cuboidal epithlium, some with single luminal cilia
Efferent ductules - “psudostratified columnar” epithelium with alternatign clusters of nonciliated cuboidal cells and ciliated columnar
WHat is the purpose of non-ciliated cells in the ductules leading to the ductus deferens?
Absorb fluid secreted by seminiferous tubules
Excretory genital tracts
Excretory genital tracts
Excretory genital tracts
Excretory genital tracts
Excretory genital tracts
Excretory genital tracts
Ductus
Ductus
Seminal vescles
Seminal vesicles
What is the main gland contributing to seminal fluid?
The seminal vesicle (70%)
What does the secretory product of the seminal vesicle do?
Activates sperm (contains fructose)
What is the epithelium of seminal vesicles? What determines the hieght of epithelium?
Psudeostratified columnar epithelium. Varies with testosterone
What is a distinguishing feature of seminal vesicle cells?
Highly foled mucosa and yellow lipochrome pigment granules and secretory granules
Lamina propria and adventitia
The ejaculatory duct is the straight continuation of the _______
Ductus deferens
What empties into the ejaculatry duct?
The seminal vesicle
Is the ejaculatory duct muscular?
No
What is the termination point of the ejacuatory duct in the prostatic urethra?
The colliculus seminalis
What is the relationship of the prstate gland to the prostatic urethra?
Prostate surrounds urethra
What is the epithelium of the prostate?
Psudostratified columnar with patches of cuboidal or squamous. Have numerous lysosomes and secretory granules
What do the basal cells along the basal lamina of the prostate produce?
Produce a high molecular weight keratin, changes are important histologically for diagnosis of normal, hyperplastic, and neoplastic prostate
What is the ringed structure in the prostate gland?
The corpora amylacia
What does the corpora amylacia contain?
Concentrations in lumen ofglycoprotein that can become calcified
What does the prostate secrete? What regulates its secretion?
Thin fluid with proteolytic enzymes (fibrinolysin), citric acid, acid phophatase and lipids. Regulated by dihydrotestosterone
What can elevate prostatic specific antigen levels?
Infection, cancer, many other things, NOT JUST CANCER
What arethe discrete units of the prostate gland?
Branched tubuloalveolar glands arranged in three concentric layers around the urethra
What are the differences of entry of mucosal and submucosal and main secretions from the prostate?
Mucosal secretes directly, submucosal dsecretes into ducts and prostatic sinus
Why is the fibroelastic capsule of the prostate important?
Can contain prostatic cancer and prevent it from metasticizing
Does the prostatic capsule contain smooth muscle?
Yes
Where are Cowper’s glands located?
Adjacent to the membraneous urethra
What is another name for the bulbourethral gland?
Cowper’s glands
What is the secretion of the bulbourethral gland?
Alkaline mucous type secretions
What is the epithelium of bulbourethral glands?
Simple cuboidal or columnar epithelium
What important structures have fibroelastic capsules?
The prostate and the bulbourethral gland
What kind of muscle is contained in Cowper’s glands?
Both smooth and skeletal
What are the major components of the reproductive system/
Testes, epididymis + genital ducts, accessory reproductive glands (prostate, bulbourethral glands, seminal vesicles) and penis
Where are seminiferous tubules located?
In the testis
What is the purpose of the pampiniform plexus with respect to their position of the testicular artery
Heat exchange to keep testis cool
What are the tunics of the testes and how are they layered?
Tunica vaginalous - serous sac that partially covers anterior and lateral surfaces
Tunica albuginea - thick, fibrous connective tissue capsule - same level: Mediastinum testis - posterior thickening of TA - forms testicular lobules
Tunica vasculosa - Highly vascular layer of loose CT
The pyramidal shaped compartments separated by incomplete septa with 1-4 seminiferous tubules is called a ____________
Testicular Lobule
