Week 4 Flashcards
what does the carnivore male repdoctive system include?
paired testes, paired gonadal tracts, accessory glands, urethra + penis
what form the accessory glands?
ampulla, prostate, bulboeurethal gland, vesicular glands.
describe the functions of male repdoctive system?
productions of gametes, androgens hormones, testosterone, production of semen,
name the external genetalia of male reprodo?
penis, prepuce, scrotum, testis
describe the canine penis?
extensive erectile tissue. consists of root, body, glands
Os penis present
Slung between thighs.
describe the Root and Body of penis?
2 crura (left and right Crus) with urethra between and combine to form body. corpus cavernosum - allows for erection to occur - connective tissue causing arose crura of penis and testis
what is the Tunica albuginea?
fibrous envelope that extends the length of the corpora cavernosum penis - allows for erection tissue and function.
describe the corpus spongiosum penis?
formed from vascular leave around urethra.
begins the Bulb of penis, and continues around urethera
expands distal to corpus cavernosum to form glands
Uretheral orifice - tip of penis.
describe the Os penis?
BONE that is distal end of corpus cavernosum, ventral groove - protects Urethra!
what is the Pars long glandis
split into bulbus and a pars longa.
pars longa is the distal three-fourths. During erection the dorsal part in particular is swollen enormously.
describe the prepuce?
invagination of abdominal skin, opens caudal to umbilicus, contains two layers - lamina externa and lamina interna
describe the lamina interna?
hairless, lined with lymphoid tissue, smegma - secreting preputial glands. paired muscle arise from cutaneous trunci.
in a new born - prepuce and penis are fused.
what are some clinical problems in the prepuce?
congenital narrowing of preputial orifice - prevents extrusion of penis = phimosis
what is paraphimosis?
the inability to retract penis - impaired circulation.
name the 4 penile muscles?
1) Bulbospongious (single) - continue of uretheralis.
2) Ischiocarvernosi (paired) - arise from ischium + enclose crura
3) Ischiourethralis - passes into fibrous ring, encloses penis veins.
4) Petractor penis - mainly smooth muscle
describe the penile arterial supply?
Internal pudendal artery - artery of penis = perineal arteries, dorsal artery of penis, deep artery of penis, artery of bulb = corpus spongiosum.
external pudenual artery = preputial arteries.
describe the penile venous drainage?
Dorsal vein supples bulb of penis and corpus cavernosum
Fibrous ring associated with ischourtatheiros (erection)
describe the 2 stages of Penile Erection?
1 = increased blood flow through artery, occlusion of venous outflow.
dilation of cavernous spaces to arterial pressure.
2 = contraction of ischiocavernous + bulbospongious, blood forced into cavernous spaces above arterial pressure. in Rhythmic fashion.
what occurs in the dog during erection?
the corpus spongiosum expands MORE than corpus cavernosum which allows for the ‘tie’ to occur.
Dog dismounts + faces away from bitch, bulbous glands remain swollen,
Bulbospongious eventually relaxes and allows for escape of blood.
describe the scrotum?
location varies with species.
thin skin - optimum temperature blow body temp (3degrees cooler)
medium groove denotes internal spectrum.
describe the lining of the testis skin?
Dartos - smooth muscle
contracts to bring close to body.
describe the Dartos muscle?
internal spectrum formed for darts - divides into right/left compartments.
what is the vaginal tunica?
the pampiniform plexus contains through inguinal canal the spermatic cord, testis + epididymis.
describe the inguinal canal?
poetical space - slit between caudal abdominal wall muscles, runs between superficial + deep inguinal rings.
what is the function of the inguinal canal?
allows transmission of testes to scrotum - contains spermatic cord.
describe the carnivore testes?
produces gametes below body temp, contained with vaginal tunic, small to farm animals.
describe the capsule in the testes
tunica albuginea, connective/smooth tissue, epididymis lines the testicle
parenchyma describe it?
brown/yellowish soft tissue.
interstiutum - leading cells, seminiferous tubules
what is the mediastinum testes?
contains Rete testis, drain to head of epididymis, via efferent ductules - semiferous tubules.
describe the epididymis?
head, body, tail = sperm travel in that way.
what do efferent ductules combine to form
convoluted epididymal duct
can also store sperm and let it travel
name the ligaments used for attachment of testicules?
ligamentous structure, proper ligament of testes - attaches tail of epididymis to testis
scrotal ligament - attaches parrell tunic to scrotum
what is the spermatic cord?
contained with vaginal tunic, testicular artery/vein, lymphactis, cremated muscle.
what does the deferent duct do?
carries sperm to prostatic urethera , runs with testicualr vessels
crosses dorsal bladder neck - enters prostate + joins urethera
describe the testicular artery ?
bulk of spermatic cord, branch form abdominal aorta,
runs to vaginal ring, craniel and caudal epidiydimal branches.
describe the testicular veins?
drains blood from testes, elaborate pampiliform plexus wrapped round convoluted testicular artery!
allows heat exchange.
what does the pampilliform plexus do?
is a venous plexus – a network of many small veins found in the human male spermatic cord, and the suspensory ligament of the ovary.
what is the spermatic cord?
continued with vahginal tunic, deferent duct, artery + vein. Cremaster muscle
describe the deferent duct?
carries sperm to prostatic urethera.
runs with testicualr vessels
enters prostate + joins urethera
in dogs slight dilation
describe the testicular artery in spermatic cord?
bulk of spermatic cord, runs to vaginal ring, extremely convoluted distally, crainal and caudal epididymal branches.
describe the testicular vein in spermatic cord?
drains blood from testis,
elaborate pampilliform plexus wrapped around convoluted testicualr artery. - allows heat exchange between vein and artery to cool the blood heading to testis
what is the cremaster muscle?
origin - internal abdominal obligue muscle.
runs along parietal vaginal tunic.
allows retraction of testes.
describe imaging of testis?
ultrasound - allows detection of testicular masses.
describe testicular decent?
Gubernaculum testis - mesenchymal - extends form abdominal testis through inguinal canal to scrotum.
what are the 3 layers in the gubernaculum testis?
Pars propria
Pars vaginallis
Pars infravaginalis
how does swelling of the gubernaculum cause opening for lingual canal?
allows for draw of testis into scotum.
what happens when testicular decent goes wrong?
Cryptorchidism - occurs - undefended testis in inguinal canal.
may also be in abdominal cavity
more likely to develop neoplasia.
describe the accessory glands in the pelvic reproductive organs?
ampulla glands
prostate glands
urethra - runs from orifice at bladder neck to external orfiice at top of penis.
describe the pelvic/internal urethra?
initially contained within prostate, dorsal ridge ion lumen, caudally lives on pelvic floor.
describe the penile/external urethra?
runs through penis between cavernous tissues groove of os penis.
describe the ampulla gland (dogs only)?
dilation of terminal vas deferent before entering prostate, lined with glandular tissue, small portion of ejactulate, capsule + septa with smooth muscle.
describe the Prostate?
bulk of semen production
two parts - 1. large compact section around proximal urethra - bilobed
2. vestigial disseminated part with urethera mucosa.
bigger in dogs than cats
how is the prostate divided?
L + R lobes with grooves by dorsal groove.
smooth capsule with smooth muscle, completely encloses urethra in DOGS
vascular supply via prostate artery.
prostate enlargement? describe it?
most common to hormonal influence, Benign prostatic hyperplasia. inflammation, neoplasia, cystic disease. more common in dogs than cats ultrasound used.
explain the stallion male reproductive anatomy>
penis = musclarcavounous
deferent ducts - prostate, vesicular glands, bulbonal glands, ampulliae
explain the ruminants male reproductive anatomy?
fiberoelastic penis = sigmoid flexure, Long narrow prepuce, pendulous scrotum,
Vas deferences - ampullae , prostate, vesicular glands, bulbonal glands
explain the Boar male reproductive anatomy?
Fiberoelastic penis - sigmoid flexure - perinatal scrotal location, large vesicular and bulbortaral glands with prostate aswell. 200-1000ml ejaculate.
explain the equine male reproductive anatomy?
expansion of corpus spongiosum over apex of penis,
neck = collum glandis
head = corona glands
dorsal process = extends over corpus cavernosusm.
describe the equine prepuce?
Additional fold in wall, allows erection to occur, preputial orifice outer membrane to preputial cavity.
preputial ring - entrance to inner sleeve
glandular lining -
describe erection in stallion?
increased blood flow - venous occlusion, contraction of ischiocavernous muscle
engorgmnet of cavernous spaces.
65ml of ejaculate average.
describe the Fibroelastic penis? (boar-ruminants)
corpus cavernosum - small blood spaces.
corpus fibroelastic tissue - rigid when not erect. rapid erection - not much blood needed.
name the penile muscles?
Paired retrator penis muscles. Urethrailis Bulbospongious Ischiocavernous Ischiourthralis
describe the paired retractor penis muscles?
caudal vertebrae, around to rectum.
attaches at 2nd bend of sigmoid flexure, contrition through sympathetic nerves.
describe the body of the ruminant penis?
1m long in bull
Circular cross section
outer fibrous tunic, tunica albengina
suspensory ligaments suppost caudal body
describe the glands of the ruminant penis?
small soft, asymsymtrical, vertically bent
urethral process projects out
sigmoid flexure - palpable caudal to serotum
describe the ruminant prepuce?
long narrow, skin upper lesser
longnitudal folds.
describe the boar penis?
thin, relativity long (60cm when flaccid)
shaft of penis - spirals
erection length increases ^ 25% turns about more 6 times
descirbe the boar prepuce?
long, narrow caudal part houses and of penis.
preputial diverticulum in pig - dorsal to craniel portion
may become influential + resins umbral hernia.
describer the equine scrtoum + testis?
located beneath pubis
central raphe extends from perineum to prepuce.
thick skin with sebaceous glands.
no visible mediastinum
describe the ruminant testies?
large and plump, vertically-orientated in scrotum.
tortuous intrascapular vessels seen on surface.
describe why the ram has different testis?
ram testis are covered in wool – this may increase the temp so need to make sure it doesn’t effect temp, by trimming or removing.
what are karyotyping?
is the process of pairing and ordering all the chromosomes of an organism, thus providing a genome-wide snapshot of an individual’s chromosomes
describe how karyotyping works?
nucleated cells isolated from minerals ⬇️ cells undergo cell division ⬇️ 'arrested' in metaphase (in mitosis) ⬇️ stained on slides + dropped onto slide
what are the different types of staining when karyotyping?
light and dark banding pattern
characteristic for each chromosome
change can be used to detach abnormalities
can metaphase chromosomes be used?
yes they can be replicated + condensed so can use a light microscope for viewing.
what are the 3 different types of centromere positions?
Acrocentric - 3/4 way up the chromosome
metacentric - 1/2 up
telocentric - tip of chromosomes
what is Aneuploidy?
Presence or absence of one or more chromosome usually effecting X chromosome.
changes in chromosome numbers
what does mosaic mean in chromosome behaviour?
animals with one or more cells derived a single zygote
what happens when free Martin cattle are chimeras?
2 emybros develop 1 female 1 male - placenta anatomies can occur - 90%
98% female calf born but will be infertile.
male twin is also chimera- normal genitalia but sub fertile.
what is Trisomy 21
down syndrome - most common chromosal abnormality amongst human live births.
what is SRY?
responsible for male sex determination in mammals.
describer molecular basis in horses?
male and female reversal in horses - normally have SRY-ve hence lack in processes that cause a fetus to develop gonadas.
what are the main XXY abnormalities?
makes with an extra X chromosome
causes infertility
in humans known as Klinefelter syndrome
1-1000 births
name the changes in chromosome structure?
they arise when chromosome breaks + not returned to original struture
genetically balanced
types would be - deletion, duplication, inversion, translocation
what is roberstain translocation?
centromere of two Acrocentric chromosomes fuse together to give one large chromosome.
what are the main causes of roberstain transolaction?
may be inherited, others can occur as random events in formation of reproductive cells
what are receptor superfamilies?
G-protein-coupled receptors
seconds, muscaric, ACh receptors.
Nuclear receptors
hours, oestrogen
how are hormones used for reproductive pharmococloy?
used act as different receptor types, different hormones has different half-lifes and receptor affinity.
how is GnRH used for ovulations in female?
GnRHs synthetic analogues are used to induce ovulation in anovualury female animals.
what does a small dose of GnRH cause?
small does ➡️ induction of LH pulses ➡️ stimulates oestradiol synthesis in selected follicles
what does a large dose of GnRH cause?
High does ➡️ induction of gonatodtopin surge ➡️ ovulation of sleeted follicles 36hrs.
what effect does an very potent GnRH receptor agonist cause on gonadtophin secretion?
will inhibit secretion after initial flare effect. LH declines - causes down regulation of GnRH receptors .
Gondatrope cell is no longer GnRH responsive.
how is infertility effected?
GnRH angles can be used as a diagnostic test for infertility.
using long term GnRH angle implant to temp suppress reproduction.
what are some reversible contraception techniques used?
1) Seprelonin for feral cats + dogs used in trap/release primates.
2) Nicarbazin bait to control pest bird species by preventing hatching of eggs.
3) GnRH vaccine e.g) Gonacam TM
4) porcine zona pellucida vaccine
what steroid hormones are used for contraception techniques?
progesterone, oestradiol + derivatives used frequently
causes synchronised oestrus and ovulation leads to: treatment of cystic ovaries,
oestrogen/androgen dependent tumors,
prevention of blood abortions.
Progesterone can be medically modified for longterm activity or oral use for small animal contraception.
how are pregnane steriod used in bitchs to control birth?
used as a contraception in all dogs
But… progesterone receptor antagonist Aglepristone, abolishes progesterone actions + terminates pregnancy in the bitch.
CLs maintain pregnancy in a long luteal phase via progesterone effects on the uterus + fetus.
Terminating the pregnancy will cause effects to not effect.
in LA how can the luteal phase be controlled?
PGF2-a used to manipulate the reproductive cycle by controlling time of lutelyosis.
in LA how can parturition be controlled?
induced by wing glucocorticoids imitates cortisol rise normally readying onset of partition.
in Sheep how can we advance their cycles?
melatonin treatments to mimik long nights,
Melatonin in administered as subcutaneous implant after ewes have seen daylight in spring.
Rams can be introduced 6 weeks earlier so 2 months ealier for lambing.
how does lactation occur?
ant.Pit = prolactin Post.Pit = oxytocin
Oxytocin aids the milk ejection from teat - stimulates uterine contractions aiding parturition like Ferguson reflex is activated. - stimulate alveolar myometrium cells just like milk letdown reflex action.
B2 adrenoceptors agonists will relax smooth muscles f uterus + coordinates contractions.
how does sex determination occur?
determined by genetic factors. Includes: -SRY gene -Wnt signalling pathway -Wnt4 - signalling protein B-catenin promotes female -gonadal development -RSPO7 gene - B-catenin signalling -Wilms tumor 1 - transcription factor -FOG2 + GATA4
What does SRY gene mean?
Y chromosome indicated that testis formation SRY (sex region on Y chromosome)
what are the most important critical genes include?
SOX9 + FOXL2
what must occur for a female to be genetical made?
Wnt4 ➡️ B-Catenin with (FOXL2) ➡️SOX9 ❌ indifferent gonad ➡️ ovary made
what must occur for a male to be genetical made?
WT1
FOG2. ➡️SRY ➡️ SOX9 (with FOXL2, Wnt4 ➡️ B-catenin)
GATA4
leads to indifferent gonad ➡️ testis
name the 3 kidney pairs in the development of reproductive system?
pronephros
mesonephros
metanephros
what is the mesonephric duct?
mesospheric kidney runs to UG sinus.
what does the metanephric diverticulum devopl into?
has grown into the UG sinus to become ureter
what does the UG sinus develop into?
bladder.
what occurs on Day 7 of pregnancy?
primordial germ cells begin to develop before gonad starts to form.
what occurs on Day 12 pregnancy?
Germ cells migrate, travel through hind gut to sex cords./
describe the Testis devopelmnt?
1) Germ cell enters gonad
2) coelmic epithelia cells invade gonad + become sterolsi cells
3) form sec cords
4) Germ cells enter cords
5) Sex cords ‘detach’ to form semiferous tubules
6) Paramesonephric duct degernates
7) mesospheric duct persists
describe ovary development?
indfiifernet gonad - No Y chromosome so coelmic epithelium doesn’t invade to form sterols cells.
Germ cells from oocyte nests + then go form primordial follicles + some time before birth.
what is another name for Paramesonephric duct?
Mullerian duct
what is another name for mesonephric duct?
Wolffian duct
what controls occur when no testis are produced and a female is made/
leads to no testosterone ➡️ unstable mesonephric duct degernetaes ➡️ no male tract
aswell as No AMH ➡️ stable paramesonephric duct persists ➡️ female tract ✅
what controls occur when testis are produced and a male is made?
leads to Testosterone being produced ➡️ stabilise the mesospheric duct which is normally unstable ➡️ male tract ✅
Produces AMH (anti-mullerian hormone) ➡️ causes stable paramesonephric duct to degenerate ➡️ no female tract
what occurs in bovine freemartin twins that’s causes infertility?
Dizygotic bovine twins of opposite sex - placental fusion leads to blood mixing
female is always 95% infertile, due to androgen + AMH from male.
Males are often sub fertile.
fetal testis development - describe it?
Sertoli cells contain germ cells ➡️ spermatogenesis stem cells ➡️ leydig cells in interstium between twinkles contain blood vessels + lymph nodes, pertitibular myoid cells
describe the histology of testis?
fetal testis - haemotoxylin stained ( shows nuclei of cell types)
immunohistochemistry staining (shows specific cell types)
- Monocytes in RED
Steroli cells in GREEN
describe the mechanisms of development of the testis?
1) SRY induces sertoli cell differentiation
2) Sertoli cells form sex cords + then tubules.
3) Sertoli cells secrete DHh + PGF2-a to induce Lydia cells formation.
what is Dhh?
Desert hedgehog - protein encoded by DHH gene
what is PDGF-a?
Platelet derived growth factor alpha
describe the adults testis structure?
Spermastic cord above body of epididymis, below is the tail of epididymis and the gabermaculum below at the bottom. Tunic albugenia is beside body of epididymis.
describe the Leydig Cell?
found in interstitial space between tubules.
Cells function to make androgens, primarily testosterone under control of LH release from ant.pit.
what do leydig cells do in the fetus?
ensure masculinisation
what do leydig cells do in the adult?
necessary for fertility, sex drive, maintenance of secondary sex characterises.
describe the Sertoli cells?
controlled by FSH from ant.pit + androgen release from leydig cells.
essential regulator of testis devopelmen - SRY acts to S.C forms blood tests barrier.
Secretes AMH.
what is the particular myoid cell?
Contractile, androgen - dependent,
Essential for normal spermatogenesis.
describe the first stage in testis decent?
Androgens cause suspensory ligaments to degernate INSL3 starts to shorten the gubernaculum.
Leads to - androgens complete shortening of gubernaculum + movement of testis into scrotum . INSL3 + testosterone both from Leydig cells.
what does testis decent include?
Suspensory ligaments, testis, gubernaculum, scrotum, androgen, INSL3
what is called when testes fail to decent?
Known as: Cryptorchid
unilateral or bilateral. Problems with AMH, androgens, CLRP, other factors.
can cause increased risk of testicular cancer- may be inherited may cause infertility.
what is paracrine regulation?
distinct from endocrine regulators, which secrete substances directly into the blood stream, thus accessing other tissues as well.
what is spermatogeneis?
application of cell numbers
cell differentiation occurs to produce ‘DNA package’
1 cell produces = 64
meiosis = 64 = 256
stage 1 - spematogonia - proliferation stage
stage 2 - spermatogenesis - cell differentiation occurs.
hormone control - largely through Sertoli cells.
- FSH
- testosterone.
describe spematogonia?
proliferation stage
takes place on basement membrane
Diploid ➡️ primary spermatocyte ➡️ secondary speramtoyte ➡️developing sperm cells ➡️ sperm calls
describe spermatogenesis?
cell differentiation occurs - nuclear condensation ➡️ acrosome forms form goligi ➡️ tail drops from centriole ➡️ cytoplasm re-distruibes ➡️ mitochondria re-arrange in middle piece.
describe the Epididymis?
function - to induce sperm maturation non-motile, non-fertile sperm enter head + become fertile + motile as trace through epididymis.
name the type of cells in the epididymis?
Pseudostraified, columnar epithelium with stereolilied. smaller toward tail. androgen sensitive structure.
descirbe the accessory glands in the testis?
seminal vesicles
prostate
bulbourethal glands
preputial glands
Androgen + species dependent - adds fluid to ejaculate, may be essential for embryo development,
all exocrine glands
describe the seminal vesicles?
compound tubular glands- lined with tall Columnar secretary epithelium
surrounded by fibrous-muscular capsule.
