Reproduction (R1-R14) Flashcards
What sex chromosomes do avian/fish/reptile females have?
ZW
What sex chromosomes do avian/fish/reptile males have?
ZZ
This is the first part of the reproductive tract to develop from the embryonic mesoderm, but eventually degenerates
pronephros
this part of the reproductive tract develops second and replaces the pronephros.
The diverticulum forms as it develops (will eventually become the kidney)
Mesonephros
the mesonephric duct and tubule is also known as this
Wolffian duct and tubule
the paramesonephric duct is also known as this
Müllerian ducts
this hormone is secreted in males and causes destruction of the paramesonephric duct allowing the deferent duct and epididymis of testicle to form from the mesonephric tubules
Anti-Mullerian Hormone (AMH)
Jelly-like cord that extends from the testicle into the inguinal canal (covered by visceral and parietal peritoneum)
Gubernaculum
The gubernaculum shrinks to become these three ligaments in the male
the proper ligament of the testicle, the ligament of the tail of the epididymis, and the scrotal ligament
Name the fascia layers around the testicle from superficial to deep
Skin
Tunica Dartos
External Spermatic Fascia
Cremaster Muscle
Internal Spermatic Fascia
Parietal Vaginal Tunic
Vaginal Cavity
Visceral Vaginal Tunic
Tunica Albuginea
What does the tunica dartos layer of the testicle originate from?
fibroelastic and smooth muscle
What does the external spermatic fascia layer of the testicle originate from?
external abdominal oblique muscle
What does the cremaster muscle and fascia layer of the testicle originate from?
internal abdominal oblique muscle
What does the internal spermatic fascia layer of the testicle originate from?
transverse abdominal muscle
What does the parietal vaginal tunic layer of the testicle originate from?
peritoneum
What does the visceral vaginal tunic layer of the testicle originate from?
peritoneum
What does the tunica albuginea layer of the testicle originate from?
white fibrous sheath covering the testis
male gonad producing spermatogonia and testosterone
testes
part of male repro tract: formed by epididymal duct and connected to the testes - where spermatozoa mature (head, body, and tail)
epididymis
part of male repro tract: continuation of epididymis, travels through spermatic cord to abdomen, arches caudally to the prostate gland, and opens into pelvic uretha
deferent ducts
part of male repro tract: extends from inguinal ring to testes and provides passageway for testicular vasculature, lymphatics, and nerves
-contains vas deferens, cremaster muscle, and pampiniform plexus
Spermatic Cord
part of male repro tract: glands associated with urethr that add seminal plasma to ejaculate
-comprised of ampulla, prostate, vesicular, and bulbourethral glands
accessory sex glands
male copulatory organ that provides passageway for spermatozoa and urine to exit the body
-made up of root, body, and glans
penis
these are contractile cells surrounding the basement membrane and help move spermatozoa out of the tubules
Myoid cells
This is tissue between the seminiferous tubules that contains numerous cell types (connective tissue, nerves, blood, and lymphatic tissue)
Interstitial tissue
these cells develop during puberty and secrete testosterone
Leydig cells
These are elongated pyramidal cells found in the seminiferous tubules of the testicle along with germ cells
-Function: support the developing spermatozoa and produce a number of regulatory factors that provide an optimum environment
Sertoli cells
these cells are found in the testicular interstitium and produce testosterone
Leydig cells
These are thick muscular tubes that transport sperm from the epididymis to the urethra
Deferent ducts (ductus deferens, vas deferens)
Male accessory sex gland present in dog, horse, cattle and sheep but NOT cat and pig
-enlargements of the deferent ducts that open into the pelvic urethra
Ampulla
Male accessory sex gland present in all species
-consists of a visible body surrounding the neck of the bladder, a disseminate part consisting of lobules in the wall of the pelvic urethra or both
Prostate
Male accessory sex gland present in horse, cattle, sheep and pig but NOT cat and dog
-paired structures located dorsolateral to the neck of the bladder
Vesicular glands
Male accessory sex gland present in cat, horse, cattle, sheep and pig but NOT dog
-paired glands on the dorso-caudal aspect of the pelvic proximal urethra and near the bulb of the penis
Bulbourethral (cowpers)
paired erectile tissue with large venous spaces in the penis
-left and right bodies separate proximally forming the crura (makes up the root of the penis with the bulb)
Corpus Cavernosum (CCP)
Tube of erectile tissue directly enclosing the urethra
-forms the bulb and glans of the penis
Corpus Spongiosum (CSP)
Cutaneous sheath around the glans of the penis in the non-erect state
Prepuce
high connective tissue content that causes the penis to be firm when not erect
-erection achieved by extending the length and stiffening via blood engorgement with NO increase in diameter
-“Showers” (ruminants and boars)
Fibroelastic penis
low connective tissue content causing the penis to be flaccid when not erect
-erection accomplished by engorgement with blood which stiffens the penis and increases length AND diameter
-“Growers” (carnivores and horses)
Musculocavernous penis
This artery supplies the penis with 3 branches (artery of the bulb, deep artery of the penis, dorsal artery of the penis)
Internal pudendal artery
This branch of the internal pudendal artery supplies the corpus spongiosum (CSP)
Artery of the bulb
This branch of the internal pudendal artery supplies the corpus cavernosum (CCP)
deep artery of the penis
This branch of the internal pudendal artery supplies the pars longa and bulbus glandis
dorsal artery of the penis
this type of innervation is for ejaculation and anti-erectile via the hypogastric nerve and cavernous nerve
sympathetic
this type of innervation is pro-erectile via the pelvic nerve and cavernous nerve
parasympathetic
this type of innervation is penile sensation and contraction of striated muscles during ejaculation via the pudendal nerve
somatic
external female genitalia that leads into the reproductive tract
vulva
this separates the female reproductive tract from the rectum in domestic animals
rectogenetial pouch
a portion of the peritoneum fuses to form this, which supports the female repro tract in addition to housing vascular, lymphatic and nerve structures
broad ligament
what are the three parts making up the broad ligament?
mesovarium, mesosalpinx, mesometrium
female copulatory organ, site of urine expulsion, and passive birth canal
vagina
this is the caudal vagina, portion common to the urinary and repro systems
extends from the opening of the urethra to the labia of the vulva
vestibule
small blind pouch ventral to the urethral opening on the floor of the vestibule in the cow and sow
suburethral diverticulum
thick walled organ that provides a physical barrier between the vagina and uterus
cervix
the organ of pregnancy, connects the cervix to the oviduct
uterus
the structure that connects the uterine horn and ovary
consists of infundibulum, ampulla, and uterotubal junction
oviduct
ovoid structure in the female repro tract with an outer tunica albuginea
consists of a cortex and medulla
ovary
this artery supplies the uterine body and horn
arises from the internal or external iliac artery
uterine artery
this artery supplies the ovary, oviduct and cranial aspect of uterine horn (uterine branch), arises from the aorta
ovarian artery
this artery supplies the vaginal and caudal part of the uterus (uterine branch) and the vestibule (vestibular branch), arises from the pudendal artery
vaginal artery
identification of this “vibration” in the middle uterine artery is one of the many signs of pregnancy in the cow
Fremitus
what are the 3 histological layers of the vagina?
submucosa, muscularis externa, adventitia
this histological layer of the vagina contains connective tissue and lymphoid nodules (in caudal portion of organ)
submucosa
this histological layer of the vagina contains smooth muscles arranged circularly and longitudinally
muscularis external
this histological layer of the vagina is a thin layer of dense connective tissue with extensive venous plexus
adventitia
the stratified squamous epithelium of the vagina is thin with only 2-3 cell layers during this part of the oestrus cycle
Anoestrus
stratified squamous epithelium of the vagina with keratinization, thick (up to 20 cell layers) during this stage of the oestrus cycle
proestrus
stratified squamous epithelium of the vagina with keratinization, thick (up to 20 cell layers) during this stage of the oestrus cycle
proestrus
keratinization of the vaginal epithelium reaches a maximum during this stage of the oestrus cycle then declines, intraepithelial mucus glands are present
oestrus
the vaginal epithelium becomes thinner along with a decrease in keratinization during this stage of the oestrus cycle
dioestrus
this type of uterus has two cervical canals that separate each horn into distinct compartments, often seen in marsupials and rabbits
duplex uterus
this type of uterus involves a single vagina and cervical canal leading into a common uterine body that splits in two (bifurcates) to form 2 uterine horns,
seen in mare, cow, ewe, sow, bitch, and queen
bicornuate uterus
this type of uterus involves a single vaginal Cana, single cervix, and single uterine body with no uterine horns,
seen in humans and primates
simplex uterus
what are the 3 histological layers of the uterus
endometrium, myometrium, and perimetrium
what are the two parts of the endometrium (of the uterus)?
zona functionalism and zona basalis
this ligament is located between the two uterine horns
intercornual ligament
this ligament provides support for the ovary by attaching it to the uterus (sometimes called the proper ligament of the ovary)
utero-ovarian ligament
this ligament runs along the lateral surface of the broad ligament from the cranial tip of the uterine horn towards the inguinal canal,
equivalent to the male gubernaculum
round ligament of the uterus
these cells in the surface epithelium of the oviduct are most numerous on the infundibular surface and least numerous in the isthmus and interstitial segments
ciliated cells
these wedge-shaped cells without cilia in the surface epithelium of the oviduct have secretory granules in their cytoplasm and provide nutrients to ovum during its passage through the oviduct
Peg Cells
Two parts of the ovary (reversed in the mare)
outer cortex and inner medulla
this is the structure on an ovary containing an oocyte surrounded by specialized epithelial cells
follicle
this type of follicle is an oocyte surrounded by a single layer of flattened follicular cells called granulosa cells
primordial follicle
this type of follicle is a stimulated primordial follicle, the oocyte enlarges and the granulosa cells divide
primary follicle
this are spindle-shaped cells on the ovary, stromal cells surrounding the follicle differentiate into several layers of these as the follicle grows
theca cells
this is a fluid-filled cavity that develops among the granulosa cells as the follicle becomes larger
antrum
a collapsed follicle becomes this after the ejection of the oocyte as blood flows into the antrum
corpus hemorrhagicum
this is a pale structure that will continue to shrink, eventually forming a small scar on the side of the ovary - remnant of a follicle
corpus albicans
This a small, but complex structure lying between the midbrain and forebrain & split into halves by the third ventricle
Hypothalamus
This is located in the hypophyseal fossa of the sphenoid bone just ventral to the hypothalamus
Pituitary gland (hypophysis)
What are the 3 lobes of the pituitary gland?
anterior lobe, posterior lobe, intermediate lobe
this lobe of the pituitary gland develops from Rathke’s pouch in the embryo and is also known as the adenohypophysis
anterior lobe
this lobe of the pituitary gland is derived from the ectoderm and is connected to the hypothalamus by a little stalk, aka the neurohypophysis
posterior lobe
this lobe of the pituitary gland is a tiny division of the adenohypophysis and sits between the anterior and posterior lobes
intermediate lobe
axons of neurons in the supraoptic and paraventricular lobes of the hypothalamus project into this lobe of the pituitary
posterior lobe
the hypothalamus communicates with this lobe of the pituitary via a vascular network
anterior lobe
this hormone stimulates the synthesis and secretion of the gonadotrohins FSH and LH
Gonadotrophin Releasing Hormone (GnRH)
this hormone stimulates oestradiol production in follicular granulosa cells and acts on Sertoli cells of the testicle to stimulate sperm production
Follicle Stimulating Hormone (FSH)
this hormone stimulates uterine contractions, and milk let down in the mammary gland via contraction of mammary myoepithelial cells
Oxytocin (OT)
this hormone stimulates milk production in the mammary gland and is luteotrophic. Also inhibits GnRH production therefore reducing production of gonadotrophins (FSH and LH)
Prolactin (PRL)
This hormone triggers ovulation and CL development in females, and stimulates testosterone production by testicular Leydig cells in males
Luteinizing Hormone (LH)
the release of gonadotrophins (FSH and LH) is controlled by GnRH acting on these cells in the anterior pituitary
gonadotroph cells
this is a neuropeptide hormone synthesized in the hypothalamus and stored in the posterior lobe of the pituitary gland - Acts on muscles of the repro tract in males and females causing contraction
oxytocin
this is a protein hormone produced mainly by lactotroph cells in the anterior pituitary; primary action in females is to initiate lactogenesis; production inhibited by dopamine
prolactin
this is the process of gaining reproductive capacity and is dependent on adequate production of GnRH by the pituitary to stimulate gametogenesis
puberty
what theory of puberty?
hypothalamus us highly sensitive to negative feedback actions of gonadal steroids before puberty but becomes much less sensitive at puberty resulting in increased GnRH and gonadotrophin release
gonadostat theory of puberty
what does the maturation of the hypothalamic-pituitary-gonadal axis theory state is the trigger for onset of puberty?
increase in GnRH pulsatility
What are the three main factors responsible for timing the onset of puberty?
age, breeds, nutrition
this stage of spermatogenesis occurs in the basal compartment of the seminiferous tubule and is mitosis of Spermatogonia A -> Spermatogonia B -> primary spermatocytes
Proliferation
this stage of spermatogenesis occurs in the aluminas compartment and is meiosis of primary spermatocyte -> 2 secondary spermatocytes -> spermatids
Meiosis
this is the name for the entire process of division of Spermatogonia A into spermatids
Spermatocytogenesis
this stage of spermatogenesis is when spermatids differentiate into spermatozoa, are extruded into the lumen, and finish maturation in the epididymis
Spermiogenesis
this is formed by the tight junctions between Sertoli cells that divide the tubule lumen into two compartments; it prevents spermatozoa leaking into the systemic and lymphatic circulation and helps ensure the lumen environment is optimal for sperm development
Blood-testis barrier
This part of a sperm contains an acrosome and nucleus
the head
this part of a sperm is responsible for its forward propulsion and contains the mitochondria and a fibrous sheath
tail/flagellum
testicular function is governed by this axis
hypothalamic-pituitary-testicular axis
this is the process whereby immune follicles develop into more advanced follicles
folliculogenesis
this is an immature follicle, the oocyte is surrounded by a single layer of cells
primordial follicle
this is a slightly more advanced follicle that go on to either develop further or degenerate
primary follicle
this is a follicle where the oocyte is surrounded by 2+ layers of cells but without an antrum or cavity
secondary follicle
this is a follicle where the oocyte is surrounded by a number of cell layers and has an antrum filled with follicular fluid
tertiary follicle
the ovarian follicle undergoes significant tissue change during ovulation and becomes this, defined by blood vessels in the follicle rupturing
corpus hemorrhagicum
follicular cells differentiate into luteal cells to form this
corpus luteum
the corpus luteum degenerates and becomes known as this
corpus albicans
follicles become dependent on hormone support from the pituitary in order to continue development during this stage of follicular development
antral development
during early antral development, this hormone binds to its receptors on the granulosa and stimulates it to produce oestradiol
FSH
during late antral development, rising oestrogen levels stimulate appearance of receptors for this hormone on granulosa cells
LH
this is an inflammatory response resulting in the breakdown of the follicular wall to allow the oocyte to be released
ovulation
this type of ovulation occurs regardless of mating
spontaneous
this type of ovulation occurs in response to externally derived stimulation (mating, sperm derived factors, pheromones)
induced
this is the process whereby the ovulated follicle becomes the corpus luteum (CL) - granulosa cells stop dividing and become large luteal cells
Luteinisation
this is the main hormone produced by the corpus luteum
progesterone
this type of hormones (including LH, Prostaglandin E2, and Prolactin) help maintain the CL and thus secretion of progesterone
Luteotrophic hormones
this type of hormones (ex: Prostaglandin F2a) induce destruction of the CL
luteolytic hormones
during this stage of the oestrus cycle: follicles are growing and E2 concentrations are increasing, the CL from the previous cycle is regressing and P4 concentrations drop, blood flow to the uterus increases
Proestrus
during this stage of the oestrus cycle: the female animal is in heat and will display behavioral sexual receptivity, high E2 and LH concentrations, “day 0”
Oestrus
during this stage of the oestrus cycle marks the end of oestrus, after ovulation a CL forms and P4 concentrations begin to rise again, uterine glands become coiled and secretory
Metaoestrus
during this stage of the oestrus cycle, the CL reaches maturity and P4 concentrations are at their peak, uterine glands and endometrial growth peaks
Dioestrus
this is a period of reproductive inactivity, despite continuation of follicle growth there is no oestrus behavior and ovulation does not occur
anoestrus
what are the 3 stages of reproductive behavior in the male?
precopulatory, copulatory, & postcopulatory
this stage of reproductive behavior in the male involves: search for sexual partner, courtship, sexual arousal, erection, and penile protrusion
precopulatory
this stage of reproductive behavior in the male involves: mounting, intromission, and ejaculation
copulatory
this stage of reproductive behavior in the male involves: dismount, refractory period, and memory
postcopulatory
what are the 3 stages of reproductive behavior in the female?
attractivity, proceptivity, & receptivity
this stage of reproductive behavior in the female involves behavior that attracts the male including vocalization and production of pheromones
attractivity
this stage of reproductive behavior in the female involves female behavior that stimulates the male to copulate
proceptivity
this stage of reproductive behavior in the female involves copulatory behavior that ensures insemination, including backing towards the male and lordosis
receptivity
reproductive behavior can be triggered by a series of stimuli, notably these 4 types
visual, auditory, olfactory, & somatosensory
this is a distinctive curling of the upper lip which allows further ‘sampling’ of the pheromones
Flehmen response
this is an accessory olfactory organ connected to two small openings in the roof of the mouth just behind the upper lip (responds to pheromones)
Vomeronasal organ
sexual excitement initiates parasympathetic innervation, overriding tonic sympathetic innervation leading to this - relaxation of cavernosal smooth muscle, increased blood flow to cavernosal space and venous occlusion
erection
this is when the rigid penis is inserted into the vagina and the penis continues to swell
intromission
this is stimulated by sensory nerves within the glans penis, triggers the CNS to activate SNS via hypogastric nerve creating an emission containing semen and rhythmic contractions of the bulbocavernous muscle and urethralis muscle
ejaculation
this is the process in which a spermatozoa and oocyte fuse to form a single-celled zygote
fertilization
this is the final stage of fertilization where the male and female pronuclei fuse to create a zygote
syngamy
this is when more than one sperm enter an egg, genetic material from more than one male leads to a non-viable zygote
polyspermy
this is the attachment of the developing embryo to the uterine endometrium
implantation
in these two species, the blastocyst attaches to the middle or upper third of the ipsilateral horn
cattle and sheep
in this species, the blastocyst migrates between both horns and implants in one horn close to the body of the uterus
horses
endodermal cells separate the embryonic disc and line the blastocysts cavity to form this
bilaminar yolk sac
mesodermal cells migrate from primitive streak and occupy position between the inner endodermal layer and outer trophoblast layer to form this
trilaminar yolk sac
fusion of the trophoblast layer with amniotic folds of newly formed sac form this
chorion
union of the vascular trilaminar layer of conceptus with the uterine lining forms this
choriovitelline placenta
this develops as an outgrowth of the primitive gut as the amniotic folds continue to grow up and around the embryo
allantois
this is the inner sac around the embryo made up of trophectoderm and mesoderm
amnion
fusion of the allantois and chorion make up this
chorioallantoic placenta
in this type of placenta, almost the entire surface of the allantochorion is involved in formation of the placenta - horses and pigs
diffuse
in this type of placenta, multiple discrete areas of attachment are formed by interaction of patches of allantochorion with endometrium
cotyledonary
these cells are characteristic of ruminant placenta, form when trophoblast cell nuclei divide by mitosis without accompanying cytoplasmic division
binucleate giant cells
this type of placenta is a complete (dogs & cats) or incomplete (ferrets & raccoons) band that encircles the fetus
zonary
this is the single type of placenta seen in humans, primates, and rodents
discoid
this is an organ of metabolic exchange between the fetus and the dam - it is an endocrine organ and an immunological barrier
placenta
the chorion of the fetus is in direct contact with the uterine endometrial epithelium of the dam in this type of placenta (pigs, horses, ruminants)
epitheliochorial
the chorion of the fetus is in direct contact with the uterine endometrial epithelium of the dam AND a number of fetal trophoblast cells fuse with endometrial cells to form binucleate cells in this type of placenta (ruminant)
synepitheliochorial
the chorion is in direct contact with the endothelium of blood vessels of the dam in this type of placenta (carnivores)
endotheliochorial
fetal vessels and chorion are invaginated into pools of maternal blood in this type of placenta (humans and some rodents)
haemochorial
production of this hormone by the endometrium must be blocked to prevent luteolysis
Prostaglandin F2a (PGF2a)
in a process known as this, the conceptus prevents luteolysis by ensuring progesterone concentrations remain high
Maternal Recognition of Pregnancy (MRP)
in the ruminant, the conceptus produces this molecule which binds to oxytocin receptors in the endometrium to prevent formation of new oxytocin receptors
interferon tau (IFNt)
in the pig, conceptus produces this hormone which reroutes PGF2a produced by endometrium away from the bloodstream and toward the uterine lumen (where it cannot cause luteolysis)
oestradiol
the high mobility of the embryo in this species has anti-luteolytic action
horse
this is a hormone that is thought to act in synergy with P4 to support pregnancy
relaxin
Is the mean partial pressure of oxygen (PO2) higher in maternal blood or fetal blood?
maternal blood
Is the PCO2 higher in maternal blood or fetal blood?
fetal blood
this is the transfer of antibodies from one animal to another, usually from mother to fetus
passive immunity
this is the idea that adverse intrauterine events during embryonic and fetal development results in alterations to certain structural and physiological functions of the fetus
fetal programming
this hypothesis is that origins of chronic diseases of adult life lie in fetal responses to intrauterine environment
Barker’s Hypothesis
this is an overall body-wide reduction/delay in organ development from insufficient or altered nutrient supply through the placenta
intra-uterine growth restriction (IUGR) or Fetal Growth Restriction (FGR)
what are the three stages of parturition?
- initiation of myometrial contractions
- expulsion of the fetus
- expulsion of the fetal membranes
during one of the first early stages of parturition, this is converted to oestradiol (E2), resulting in the removal of this to myometrial activity
progesterone (P4); progesterone block
fetal corticoids stimulate secretion of this by the placenta, causing the corpus luteum of pregnancy to regress and further diminish P4 concentrations
Prostaglandin F2a (PGF)
the myometrium becomes more active and pushes the fetus towards the cervix causing pressure on the cervix when these two levels become elevated
E2 and PGF
this is released from the pituitary in response to pressure neurons in the cervix become activated during parturition; it facilitates myometrial contractions
oxytocin (OT)
what is the positive feedback loop of oxytocin (OT) during parturition?
activated pressure sensitive neurons in cervix cause OT release by pituitary which facilitates myometrial contractions, which results in more cervical pressure & therefore more OT release
what signals the end of the first stage of parturition?
the fetus moves into the cervical canal
what is the onset of parturition triggered by?
the fetus (elevated fetal corticoid production)
expulsion of the fetus requires strong contractions of these two muscles
myometrial and abdominal
PGF production stimulates the production of this, which causes the cervical tissue to soften and the pelvic ligaments to relax, making it easier for the fetus to pass through the birth canal
relaxin
the cervix and vagina produce mucus during parturition in response to this elevated concentration prior to parturition
E2 (oestradiol)
what functions do the mucus produced by the cervix and vagina serve during parturition
washes out the cervical seal of pregnancy and lubricates the birth canal
what marks the end of stage 2 of parturition
fetal membranes rupture due to pressure by fetus resulting in loss of amniotic and allantoic fluid
these contractions are responsible for the physical expulsion of the placenta
myometrial
expulsion of the placenta requires these to be dislodged from the maternal side
chorionic villi
what is believed to cause the dislodging of chorionic villi from the maternal side of the placenta
vasoconstriction
these 2 changes play important roles in the break down of the placenta
- changes in hormonal environment to favor enzymatic breakdown of cotyledon-caruncle linkages
- activation of maternal immune response against fetal membranes
this is the postpartum period following birth where the mother undergoes physiological change in order to return to the non-pregnant state and to produce milk for offspring
puerperium
why might a dairy cow have delayed uterine involution following birth?
calf removed early on & cow is milked 2-3 times a day so myometrial contractions not as frequent
frequent suckling of the offspring causes this hormone to be released which helps the uterus contract
oxytocin
this is the discharge produced from the remnants of fetal and maternal tissue lost over the initial few days after parturition
loch
necrotic tissue in the local tissue comes from this tissue
caruncular tissue
parturition allows the removal of the negative feedback effects of elevated E2 and the recommencement of the synthesis of these 2 hormones
follicle stimulating hormone (FSH) & luteinizing hormone (LH)
a dominant follicle is usually produced this many days postpartum
7-10 days
the fate of the dominant follicle is determined by this
LH puls frequency
what are 4 major factors in dairy cows affecting resumption of ovulation
- BCS and energy balance
- parity
- season
- diseases
what are the 3 major factors that control GnRH/LH pulse frequency (& therefore fate of early postpartum dominant follicles) in postpartum beef cows
- maternal bond/calf presence
- suckling inhibition
- poor BCS
these are the 6 most common disorders related to lactation and uterine health during the postpartum period (predominately seen in dairy cow due to high demands of lactation)
- retained placenta
- milk fever
- negative energy balance (NEB)
- mastitis
- endometritis/metritis
- fertility issues
this is a disorder of the immediate postpartum period where the mother does not expel all parts of the placenta and fetal membranes & becomes susceptible to hemorrhage and infection
retained placenta
this is a metabolic disorder characterized by low blood calcium levels, mainly affects cattle and is caused by demand for colostrum production exceeding body’s ability to mobilize calcium
milk fever (postpartum hypocalcemia)
this is common in dairy cattle and is caused by the inability to ingest enough energy from feed intake to cover the energy demands of lactation; results in loss of body condition and subsequent metabolic disorders, ‘milking off her back’
negative energy balance (NEB)
this is an inflammation of mammary gland tissue usually caused by an organism (often streptococci, staphylococci, & gram-neg bacteria)
mastitis
this is inflammation of the uterine endometrium caused by bacterial infection; purulent discharge from vagina
endometritis/metritis
during stage 1 of the development of mammary glands, ectodermal proliferation through 6 stages forms these which invaginate into the underlying fat pad forming these
mammary buds; teats
primary sprouts form during stage 1 of mammary gland development and give rise to these sinuses, known as galactophores
gland and teat sinuses
secondary sprouts form from primary sprouts during stage 1 of mammary gland development and give rise to these ducts
lactiferous ducts
at puberty, this hormone stimulates duct lengthening and branching
oestradiol (E2)
at puberty, this hormone stimulates ducts and ductule development and enlargement
progesterone (P4)
these two hormones are released in a cyclical manner during puberty and affect mammary gland development
oestradiol and progesterone
mammary growth peaks around this many days into lactation, then a gradual loss of secretory cells occurs
30 days
milk production in cattle usually peaks in this lactation and plateau for several years
5th lactation (7-8 years)
these are highly modified apocrine sweat glands consisting of compound tubuloacinar glands
mammary glands
between the basement membrane and the cuboidal secretory epithelial cells of the mammary glands is a layer of specialized contractile ___ cells
myoepithelial cells
alveoli are arranged into lobules separated by this
interlobular connective tissue
this is present in the teat wall and regulates milk let down and is erectile under stimulation
subcutaneous venous plexus
this is present in the teat wall and is closed by a smooth muscle sphincter and elastic tissue
papillary duct (teat canal)
name 3 functions of the teat:
- provide prehensile structure for attachment of the offspring, with a conducting channel for the milk
- restrict leakage from the gland between nursing periods
- provide sensory input for activation of the milk-ejection reflex by the suckling stimulus
what kind of epithelia is the teat canal covered in
stratified squamous
what is the fatty plug formed from between feeds/milking?
desquamation of the epithelia and fatty secretions
what are the two functions of the fatty plug formed in the teat canal between feeds/milking
- physically blocks teat preventing bacterial entry
- has bactericidal properties
what are the two strong fascial sheets (or laminae) of CT that suspend the heavy udder called
lateral suspensory lamina (LSL) & medial suspensory lamina (MSL)
this suspensory ligament of the udder arises cranially from the external inguinal ring and caudally from the symphyseal tendon, protects the vessels and superficial inguinal lymph nodes situated dorsally to the udder; has dense CT
LSL (lateral SL)
this suspensory ligament of the udder is made up of elastic CL, originates from the tunica flava cranially and symphyseal tendon more caudally
MSL (medial SL)
blood is supplied to the udder mainly by this artery and this smaller artery
external pudendal artery & ventral perineal artery
this artery is very large diameter and forms a sigmoid flexure as it enters the udder to safe guard against stretching
external pudendal artery
the external pudendal artery enters the udder and forms these mammary arteries
cranial mammary arteries
the ventral perineal artery enters the udder and forms these mammary arteries
caudal mammary arteries
venous drainage of the udder is by these veins
internal and external pudendal veins & subcutaneous abdominal milk vein
the udder receives innervations from these two nerves
lumbar and sacral spinal nerves
this nerve supplies the gland substance and the deeper parts of the teat wall
genitofemoral nerve (L3, L4)
does the udder receive sympathetic or parasympathetic nerve supply?
sympathetic (no parasympathetic nerve supply)
this is the process of milk production, storage and secretion from the mammary gland in order to provide the neonate with nutrition and some immune-protection following birth
lactation
this type of placenta (present in ungulates: pig, horse, ruminants) do not allow any transfer of immunoglobulins to take place so young are born with no immunity at all
epitheliochorial placentas
this is the main immunoglobulin present in ungulate colostrum
IgG
this is the main immunoglobulin present in non-ungulate colostrum
IgA
activation of this in baby ruminants shunts milk directly into the abomasum where rennet secretion causes casein denaturation and the formation of a semisolid ‘milk clot’
oesophageal groove
when ingested in colostrum, this immunoglobulin is transported across the mucosal cells and exocytosed into lymph, and thence into the thoracic lymph duct and the systemic circulation
IgG
when ingested in colostrum, this immunoglobulin acts locally in the gut to give mucosal protection
IgA
what 4 factors is the length of time to weaning depend on?
- stage of development at birth
- type of food
- requirement to reach a certain size quickly
- environmental protection
most major components of milk are synthesized in these cells which have a high rate of metabolism and a high density of mitochondria which produce ATP
mammary epithelial cells
milk is mainly stored in these between milking/suckling
alveolar compartments
animals bred for milk production generally tend to have a larger this, as this is associated with faster milk let down and some increase in milk yields
milk cistern
what is the chief role of the teat sinus?
aid suckling (rather than storage)
transport of milk from the alveolus is primary achieved by these cells
my-epithelial cells
what is the name given to the teat canal of ruminants with catecholamine sensitive smooth muscle and ingenious series of mucosal folds which form a gravity seal
Fürstenburg’s rosette
rather than actively removing the milk, what role does sucking have with milk removal?
keep young animal attached to teat and stimulate oxytocin release
this must be activated to gain access to the “udder milk”, i.e. oxytocin stimulates my-epithelial cell contractions
milk ejection reflex
mechanical stimulation of the teat activates nerve receptors in the skin & the nerve impulse travels to the brain through this
spinothalamic nerve tract
this hormone travels to the mammary gland and binds to protein receptor sites on the myoepithelial secretory cells, resulting in contraction of the cells and expulsion of milk from the mammary gland
oxytocin
this animal can feed 2 young at different ages simultaneously from 2 adjacent glands; the glands can secrete milk with different composition and volume on demand
kangaroo
a joey that has left the pouch requires milk rich in this for energy
fat
ouch-bound younger joeys require milk rich in this
carbohydrates
this animal has mammary glands but no teats so the milk is released through pores in the skin; the milk pools in grooves on her abdomen allowing the young to lap it up
platypus
in general, milk from marine mammals tend to have a high content of this
fat
milk from rapidly growing species like rabbits and rats tend to have milk with high content of this
protein
