Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology 2 > Reproductive Physiology > Flashcards

Reproductive Physiology Flashcards

1
Q

Genetic Sex

A

Chromosomal
Determined at fertilization
XX (homogametic, homomorphic) or XY (heterogametic) in mammals
ZZ (male) and ZW (female) in birds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Gonadal Sex

A

Decided by chromosomal- default is female
Testis determining genes; SRY (sex determining region of Y chromosome) and SOX9
There are also ovary-determining genes (RSPO1, WNT)- even though this is default

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Phenotypic sex

A

What the animal looks like
Tubular and external structures
AntiMullerian Hormone, Testosterone, Dihydrotestosterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Gonads

A

Initially indistinguishable (about 6 weeks in large domestic animals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SRY

A

Testis Determining Factor
Synthesized in sex cord of male
Medullary sex cords differentiate into Sertoli cells; cortical sex cords degenerate (drive to male directon)
Sex cords differentiate into seminiferous tubules
Sex cords also give rise to rete testis
Male pre-sertoli cells also produce Anti Mullerian hormone
In absence of SRY cortical sex cords develop into follicles; medullary sex cords degenerate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

AntiMullerian Hormone (AMH)

A

Secreted by Sertoli cells of fetal testis
Causes degeneration of paramesonephric (female) ducts
Absent from normal adult male
Secreted by granulosa cells of developing (antral) follicles in adult female
Amount proportional to number of developing follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Freemartinism

A

Bovine (camelids, occasionally other species)
Male and Female co-twins
Early fusion of placental circulation
-AntiMullerian hormone transferred from male to female (because of placental fusion)
-Mediates regression of paramesonephric (Mullerian) ducts
-vestigial development of vagina, cervix, uterus, uterine tubes
Almost normal vulva and vestibulum
-derived from urogenital sinus- aka not due to paramesonephric duct
Female is infertile and reproductive tract underdeveloped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Sex Reversal

A

Disagreement between chromosomal and gonadal sex
XX sex reversal: XX geneotype and some degree of testicular development
-XX male is bilateral testes
-xx tru hermaphrodite if testis and ovary present
Most human patients have SRY translocation to an autosomal chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hypothalamus: Male vs Female

A

Female hypothalamus contains two functional areas for secretion of GnRH: Tonic (arcuate ventromedial region; ARC) and Surge (preoptic area; POA) centers
Hypothalamus inherently female
-testosterone during development defeminizes the brain (T from fetal testes crosses BBB and converted to estradiol which defeminized hypothalamus, eliminating surge center
Fetal ovaries produce estradiol, but this does not cross BBB because it is bound to alpha-fetoprotein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Hormones

A

Signaling molecules produced in the body that regulate activity of certain cells and organs (Metabolism, sleep, lactation, growth, mood, reproduction, etc)
May be secreted by specific glands (e.g. thyroid)
Three main classes: steroid, peptides /proteins, eicosanoids
Bind specific receptors to induce response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Hormone delivery

A 
Endocrine
Neuroendocrine
Paracrine
Autocrine
Pheromonal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Endocrine

A

Produced in one organ to the blood stream to find target organ elsewhere
Estradiol, FSH (pituitary to blood to testes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Neuroendocrine

A

Produced and secreted by nerve cells and have direct effect on other nerve cells
GnRH (hypothalamus to pituitary)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Paracrine

A

From one cell and effects a neighboring cell

Testosterone from leydig cells influences Sertoli cells in testis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Autocrine

A

Cell produces a hormone that acts on itself

Estradiol from Sertoli cells hastens pubertal development of these cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pheromonal

A

Bruce effect, ram effects (bring ram to ewes=syncronized ovulation in all)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Supraphysiological Stimulation

A

Internalization of hormone receptors (face inside of cell) when overstimulated
Hormone becomes ineffective

(prolonged release, high dose GnRH as a contraceptive in dogs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hormone classification by structure

A

Peptides
Glycoproteins
Steroids
Prostaglandins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Peptides

A

Oxytocin, GnRH
Small molecules with few amino acids
Regulates pituitary gonadotropin secretion
Decapeptide secreted in a pulsatile manner
Both LH and FSH are secreted from the same gonadotrope cell after stimulation by GnRH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Glycoproteins

A

FSH, LH, TSH
Protein unit attached to carbohydrate unit. (changes half life so it degrades slower)

Alpha chain is common among hormones
Beta chain is unique for each hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Steroids

A

Estradiol, progesterone
Exactly the same between species
3 6C rings and 1 5C ring
Easily cross membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Prostaglandins

A

PGF2a, PGE2
Small fatty acid derivatives
Built out of molecules liberated from cell membrane
Huge variety- so lots of actions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Steroid biosynthesis

A 
Cholesterol is always the starting point
Needs to be transported into mitochondria for final component of steroidgenesis
Then to pregnenolone
To Progesterone
To androstenedion (the male steroid)
To estradiol and testosterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Estradiol

A

Major female sex steroid
Produced mainly by follicular cells in ovary (and placenta- smaller amounts in adrenal, testis, fat, and other sites)
Two cell, two gonadotrophin synthesis
Metabolized in liver!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Estradiol synthesis

A

Cholesteral -> Androstenedione (happens in theca and is stimulated by LH)
Androstenedione goes to granular cell layer and converts to estradiol with help of FSH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Estradiol Functions

A

Mediate sexual behavior and secondary sexual characteristics of female
Anabolic
Sexual behavior
Uterine development and function: Endometrium (cyclical fashion and estrogen dependent), Myometrium (estradiol increases myometrial activity)
Cervical Mucus (less viscose)
Increased progesterone receptors (uterus- nutrients from embryo -> anticipation of ovulation and pregnancy)
Vaginal Proliferation- tougher in anticipation of mating
Essential for mammary development
Mediates ovulatory surge of LH
Role in maintaining Pregnancy
Bone health

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Estrogens

A

Generic term for molecules with action like estradiol
Endogenous (produced in the body): estrone, estradiol- synthesized from androgens
Exogenous (not immediately eaten up by liver): diesthystilbestrol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Progesterone

A

Produced mainly by ovary (specifically corpus leuteum)
CL produced after ovulation
Proliferation and differentiation of granulosa cells (large luteal cells) and theca interna cells (small luteal cells)
Both cell types produce progesterone
Metabolized by liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Progesterone Functions

A

Development and function of uterus (endometrium, uterine glands)
Myometrium (quiescence-lessened activity)
Closure of cervix, increased, viscosity of cervical mucus
Maintenance of pregnancy
Development of mammary gland
Effects on brain
Effects on immune function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Progestagens

A

Class of hormones that bind to progesterone receptors and have progesterone-like actions
Critical for maintenance of equine pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Testosterone

A

Produced mainly by Interstitial Leydig cells of the testis

Metabolized mainly by liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Testosterone Function

A

Masculinization
Maturation and function of male reproductive tract
Spermatogenesis
Male sexual behavior (beyond a (low) threshold)
Muscle mass, bone density
Osteoblastic
Erythripoietic
Increased BMR (less thyroid binding globulin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Androgens

A

Class of compounds bind ing to androgen (testosterone) receptors

  • testosterone
  • dihydrotestosterone
  • androstenedione
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Hypothalamic-Pituitary Interrelationships

A

Nerves terminate in stalk and release GnRH
Anterior Pituitary releases of LH, FSH, ACTH (stimulated by GnRH from hypothalamus)

Nerve cells which release peptide hormones (oxytocin produced here)
Release of oxytocin into circulation from neurohypophysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Hypothalamo-hypophyseal-ovarian axis

A

Hypothalamus
to GnRH
to FSH and LH (production of estradiol)
FSH stimulates follicular development
Estrogen-progesterone and androgen produced by ovary
These feed back negatively to the hypothalamus and anterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Estrous Cycle Regulation

A 
Regulated by:
Pineal gland-melatonin
Hypothalamus-GnRH
Hypophysis-FSH and LH
Ovary-estradiol, progesterone, and inhibin
Uterus- prostaglandin, PF2a
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Ovary

A

Medulla: vasculature, nerve, connective tissue
Cortex: Oocytes, follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Primordial Follicles

A

Oocyte surrounded by a single layer of squamous cells
Multiply in very early pregnancy
Arrest and number stays same- no new ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Primary follicle

A

Oocyte surrounded by single layer of cuboidal cells

Activated periodically from pole- activation is a one way trip it either develops or stops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Secondary Follicle

A

Oocyte surrounded by two or more layers

Zona pellucida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Antral Follicle

A

Fluid accumulates within a cavity formed by follicular cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Folliculogenesis

A 
Primordial follicle: origin of oocyes, and origin of follicular (granulosa) cells
Committed follicle (activated follicle from resting pool to go grow): 20-30 follicles commence to growth each day. Committed to gonadotrophin-independent growth phase
Subsequent deveopment requires gonadotropin support

Most will degenerate long before they can ovulate
Oocytes penetrate early ovary and get surrounded by peripheral cells from ovary- become leydig granulosa cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Resting Pool

A

Pool of inactive primordial follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Committed follicle

A

Follicle commences development from resting pool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Gonadotropin-independent growth

A

Follicular development up to development of antrum is independent of FSH or LH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Gn-independent

A

No requirement for LH and FSH

Primordial, Primary, Seconday

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Gn-Responsive

A

Doesn’t need Gn but will be more responsive with it
Preantral
Antral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

The preantral-early antral transition

A

Formation of the Theca cell layer

Most susceptible to follicular atresia- not developing any further

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Gn-dependent

A

If you don’t have gonadotropin it won’t move on

Antral and preovulatory follicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Antral follicle components

A

Theca externa: connective tissue
Theca interna: produce androgens under LH stimulation
Granulosa cells: produce estrogen, inhibin, and follicular fluid. Responsive to FSH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Corpus Hemorrhagicum

A

Structure left immediately after ovulation (after follicle)

Antrum collapses and is filled with blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Corpus luteum

A

Theca interna and granulosa cells proliferate to fill the cavity, differentiate into luteal calls and produce progesterone
Large luteal cells (from granulosa; also secrete oxytocin and relaxin)
Small luteal cells (from theca interna)
Remains if pregnant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Corpus albicans

A

Remnant of old corpus luteum

Scar remnant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Tonic GnRH center

A

Frequency of GnRH pulses controlled by a pulse generator

Affected by internal and external signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Surge center

A

Responsible for bursts of GnRH required to achieve preovulatory LH surge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Paraventricular nucleus

A

Oxytocin synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Hypothalamo-pituitary portal system

A

Axons of hypothalamic neurons extend to blood vessels of portal system
GnRH affects anterior pituitary directly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Estrogen Function

A

Thickening of vaginal mucosa
Mucus secretion (cervix and cranial vagina)
Epithelial mitosis in endometrium
Increased secretory and ciliary beat activity in tubal cells
Endometrial edema
Myometrial activity
Estrous behavior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Ovulation

A

LH surge- precursor to ovulation
Theca interna cells produce progesterone rather than androstenedione
Collagenase (weakening follicle wall and changes to blood supply there-rupture of spot on wall)
Prostaglandins (lack of vasculature. Contractile- oocyte ejection)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

CL: Progesterone

A

Increased endometrial secretion
Reduced myometrial activity
Priming effect in brain to enhance effects of estrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Luteolysis

A

Not pregnant, need CL to go away to have another cycle
PGF2a release from endometrium
Ipsilateral (from right uterine horn to right ovary) in ruminants
Systemic (uterus to ovary by general circulation) in mare and sow
Both systemic and counter-current in camelids (systemic in left uterine horn, local exchange in right uterine horn)
Luteolytic trigger not known in dogs (CL length is same whether pregnant or not)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Hormonal Feedback Female

A

GnRH in anterior pituitary. FSH and LH released and stimulate follicle growth in ovary.
Ovary released estradiol and there is a positive feedback: Graafian Follicle increases estrogen production will stimulate LH surge.
Estradiol can also stimulate inhibin and cause negative feedback to regulate FSH release.

LH can cause CL to be maintained which releases progesterone. Negative feedback will regulate the tonic release of LH to support the CL until PGF causes CL regression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Seasonality

A

Mediated by photoperiod
perceived by eye
melatonin produced by pineal gland during hours of darkness (synthesized from tryptophan)

Melatonin increases GnRH release in short day breeders (small ruminants)
Decreases GnRH release in long day breeders (Horses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Puberty

A 
The acquisition of capability of sexual reproduction
Production of gametes
Onset of cyclicity in females
Mature sperm in males
Distinguished from sexual maturity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Sexual maturity

A

Further body growth

Adequate size for pregnancy, delivery, lactation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Puberty mediation

A

No intrinsic immaturity of gonads and pituitary

Animals may be forced to ovulate by appropriate stimulation prepubertal ovaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Hypothalamic and pituitary development

A

GnRH neurons originate outside brain in olfactory placode
Migrate through forebrain to hypothalamus
By midgestation the number of GnRH neurons and the Hypothalamic content of GnRH and mRNA are the same as adult
In contrast, LH and FSH content of anterior pituitary are low (as is encoding mRNA)
Juvenile pituitary unresponsive to acute dose of GnRH, but is easily upregulated by pulsatile infusion of GnRH

Pulse generator is dormant in juveniles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Neurobiologic Brake on prepubertal GnRH Pulsatility

A

y-amino butyric acid (GABA): negative effect of GnRH release and pulsatility
Neuropeptide Y (NPY): negative effect of GnRH release and pulsatility
Kisspeptin: positive effect on GnRH signaling. Most likely mediator of GnRH pulsatility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Leptin

A

Adipocyte hormone
Infusion of leptin can precipitate puberty
Leptin seems to sense somatic status: adequate body size and maturity (fat stores)
Increasing leptin may mediate onset of puberty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Preovulatory GnRH surge

A

Positive feedback of estradiol- enough estradiol to trigger LH surge and ovulation
Prepubertal hypothalamus exquisitely sensitive to estradiol: negative feedback on GnRH. Follicles do not develop to preovulatory size. Follicles do not produce preovulatory quantities of estradiol so surge centers are never triggered

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Puberty vs Sexual Maturity

A

Puberty occurs at a stage when reproduction is not usually desirable
Further growth required before animal may safely and successfully undergo pregnancy, parturition and lactation
Although male animals may be capable of fertilization, maturity implies ability to be consistently fertile and impregnate an appropriate number of females

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Estrous Cycle

A

Period from the beginning of one estrus to the beginning of the next (or from one ovulation to the next)
-follicular phase (proliferative phase in women)
-Luteal phase (secretory phase in women)
-Quiescent phase (anestrus)
Estrus is defined behaviorally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Polyestrous

A

Cows. Keep cycling again and again in absence of pregnancy- all year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Monestrous

A

Dogs. Each estrus is an individual event- lots of time (anestrus) between them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Seasonally polyestrous

A

horse, sheep

76
Q

Spontaneous ovulators

A

cows, mares, dogs, etc

77
Q

Induced Ovulators

A

Cats- spikes on penis to stimulate LH surge
Rabbits
Camelids
Ferrets- can die without ovulation- follicle just sits there making estradiol

78
Q

Phases of Ovarian Cycle

A 
Follicular Phase (proliferative)
Luteal phase (secretory)
79
Q

Follicular Phase

A

Proestrus and estrus
Developing follicles
Estrogen-dominated

80
Q

Luteal Phase

A

From ovulation to CL regression

Progesterone-dominated

81
Q

Male fertility requires

A 
Competent Spermatogenesis
-endocrine regulation
-thermoregulation
-spermatocytogenesis (mitosis, meiosis)
-spermiogenesis (morphological transformation)
Functional delivery system
-accessory glands
-erection, ejaculation
-libido
82
Q

Male Anatomy

A 
Scrotum
Testis
Epididymis
Ductus Deferens
Accessory glands
Penis
Prepuce
83
Q

Scrotum

A

Blood supply: external pudendal artery
Nerves: from 2nd and 3rd lumbar roots (genitofemoral nerve)
Lymph drainage: superficial inguinal lymphnode
Scrotal skin: thin, sweat glands, delicate

84
Q

Testes

A

Oval, laterally compressed
Vertical in bulls and rams; more horizontal in stallions, dogs, cats and pigs
Testicular artery follows a tortuous route before entering the testis
Testicular vein: pampiniform plexus- important in thermal regulation
Lymphatic drainage: lumbar lymph nodes

85
Q

Testicular thermoregulation

A

Testes approximately 4C lower than core body temperature
Scrotal skin is thin with numerous sweat glands. Tunica dartos
Pampiniform plexus
Cremaster Muscle (lifts and drops)
Whole body response to increase in testes temp

86
Q

Tunica dartos

A

muscular layer that crinkles or relaxed skin to cool or heat up testes

87
Q

Pampiniform plexus

A

Countercurrent arterio-venous exchange
Warm arteriolar blood entering loses its heat to the venous blood leaving the testis
So blood coming in cools off to correct temperature
Testosterone countercurrent: testosterone will leave, cross easily to artery and come right back
Reduced pulsatility: contorted and long

88
Q

Testis

A 
Seminiferous tubules: sertoli cells, spermatogenic cells
Tubuli recti 
Rete restis
Ductuli efferentes
Interstitial cells of leydig
89
Q

Blood-Testis Barrier

A

Maintains unique environment for development and maturation of germ cells
Protects germ cells from noxious agents
Prevents autoimmune response to sperm

90
Q

Blood-testis Barrier structure

A

Specialized capillary endothelium-non-fenestrated (no pores for stuff to get through)
Basement membrane
Specialized junctions between neighboring sertoli cells

91
Q

Epididymis

A

Head, body, and tail
Macroscopically, more or less cylindrical
Single tortuous duct- up to 15m long
functions in sperm maturation, storage, and transit
All epididymal functions are androgen dependent

92
Q

Penis

A

Two basic variations of penile structure in domestic animals:
Musculocavernous
fibrous
Dorsal nerves and vessels:
-dorsal nerve responsible for sensory innervations of glans penis (essential for ejaculation)
-Dorsal vessels do not communicate functionally with corpus cavernosum or corpus spongiosum in ruminants

93
Q

Musculocavernous penis

A

increase in size due to blood engorgement within corpus cavernosum penis, and to a lesser extent in corpus spongiosum penis

94
Q

fibrous penis

A

strong tunica albuginea prevents substantial increase in diameter; increase in length involves relaxation of retractor penis muscle and extension of sigmoid flexure of penis

95
Q

Endocrinology of male reproduction

A 
Anti-Mullerian Hormone (AMH)
Gonadotropin releasing hormone (GnRH)
Luteinizing hormone (LH)
Follicle stimulating hormone (FSH)
Testosterone
Estradiol
Inhibin
96
Q

Anti-Mullerian Hormone (male repro)

A

Protein
Inhibits development of paramesonephric (mullerian) ducts in male embryo
Low levels in postnatal male- elevated in cryptorchidism

97
Q

GnRH (male repro)

A

Peptide hormone
Secreted by hypothalamus
Acts on anterior hypophysis (pituitary) to increase secretion of FSH and LH

98
Q

LH (male repro)

A

A peptid hormone
Secreted by anterior pituitary
Binds and acts primarily on the leydig cells
Hence synonym interstitial cell stimulating hormone
Stimulates androgen production from leydig cells

99
Q

Prolactin (PRL) (male repro)

A

Peptide hormone secreted by pituitary gland
Enhances LH-induced testosterone secretion
More important in dogs than other domestic species
Help support lifespan of corpus luteum

100
Q

FSH (male repro)

A

Secreted by anterior pituitary gland
Acts on sertoli cells
Major action is to promote protein synthesis. At least four proteins produced
Androgen binding protein is secreted into the seminiferous tubules. It is chemically indistinguishable from testosterone binding globulin found in the serum of may species. Serves to ensure a constant high intratubular concentration of testosterone essential for the function of the epididymis, and possibly other accessory glands

Endocrine control of spermatogenesis is a complex process requiring the presence of FSH and high intratesticular androgen levels
Under FSH stimulation, sertoli cells produce inhibin, which has a negative feedback effect on pituitary release of FSH
Note that sertoli cells also produce significant quantities of estrogens
Under FSH stimulation Sertoli cells convert testosterone to dihydrotestosterone

101
Q

Testosterone (male repro)

A

Steroid hormone
Produced by interstitial cells under LH influence
Crucial for spermatogenesis
In addition to circulating levels, testes and excurrent tract have increased concentrations
Testosterone excchange occurs in the pampiniform plexus so arterial blood entering the testes has high concentration
ABP maintains high intratubular levels
Negative feedback on hypothalamus decreases GnRH and therefore FSH and LH secretion by pituitary

102
Q

Dihydrotestosterone (male repro)

A

More potent than testosterone
Local conversion in Sertoli cells an din distal tract (accessory glands, penis)
Mediator of sexual development and secondary sex characteristics
Mediator of BPH

103
Q

Estrogen (male repro)

A

Steroid hormone
Produced by sertoli cells
Local support of spermatogenesis within wall of seminiferous tubule
Negative feedback on hypothalamus to decrease GnRH and therefore FSH and LH secretion

104
Q

Inhibin (male repro)

A

Peptide hormone
Produced by sertoli cells
Negative feedback on pituitary decreases FSH secretion

105
Q

Androgen binding Protein (ABP) (male repro)

A

Produced by sertoli cells
Stimulated by FSH
Structurally similar to circulating steroid binding globulin
Functions to bind testosterone (and DHT) to maintain high intratubular concentration

106
Q

Seasonality (male repro)

A

Gonadotriptin concentrations decrease during the non breeding season
Driven by effect of photoperiod on pineal gland and subsequent production of melatonin (which is secreted mainly at night)
In long day breeders (stallion and tomcat) increased photoperiod results in decreased melatonin secretion and increased GnRH secretion
In short day breeders (small ruminants) melatonin has a stimulatory effect on GnRH secretion

107
Q

Spermatogenesis-steps

A

Spermatogonia yield primary spermatocytes by mitosis
Primary spermatocytes enter meiosis I, yielding 2 secondary spermatocytes each
Each secondary spermatocyte undergoes meiosis II, yielding 2 spermatids
Spermatids undergo morphological changes to produce mature spermatozoa

Duration
Waves
Stages

108
Q

Spermatogenesis

A

Formation of spermatid from spermatogonia

109
Q

Spermiogenesis

A

Morphological change of spermatid into spermatid into spermatozoa

110
Q

Sperm in Epididymis

A

Transit takes about 2 weeks
Sperm acquire capability for mortality and fertilization
Sperm are stored in tail of epididymis

111
Q

Treating a bull with poor libido with testosterone injections

A

may cause liver damage

112
Q

Erection

A

Corpus Cavernosum
Corpus spongiosum
Ischiocavernosus muscle (pudendal nerve)

113
Q

Erection in Ruminants

A

Corpus cevernosum: vasodilation- BO here will rise and meet arterial BP. Retractor penis relaxes so penis is extended
Corpus spongiosum
Ischiocavernosus muscle: clamps down hard at root of penis when about to mount and prevents blood from draining out of cavernosum and so blood is under high pressure. Low additional blood volume

114
Q

Emission

A

Ejection of sperm from epididymis

115
Q

Ejactulation

A

Ejection of semen from urethra
Reflex afferents: glans penis to pudendal nerve to spinal cord
Efferent: hypogastric nerve to muscles. Neuro-endocrine loop (oxytocin)

116
Q

Ejaculation (anatomy)

A 
Epididymis
Ductus deferens
Accessory glands
Penile muscles
Urethra
117
Q

Seminal Fluid

A

Testes
Accessory sex glands: ampullae, vesicular glands, prostate, bulbourethral glands, depending on species.
Prostaglandins, citrate, fructose, zinc, mucus
Important for sperm motility, metabolism, uterine contraction, DNA stabilization, control of capacitation, immunoregulation etc
B nerve growth factor: ovulation inducing factor

118
Q

Copulation

A

Visual stimuli
Penile sensation
Musculoskeletal system
Inititate ejaculation

119
Q

Ovum development in fetal life

A

Primary germ cells originate near yolk sac and migrate to developing ovary
Differentiate to oogonia and multiply by mitosis
Enter prophase of first meiotic division (primary oocytes)
Most mammals are born with oogenesis at primary oocyte stage

120
Q

Postnatal Oocyte development

A

Diplotene nucleus remains in resting stage: germinal vesicle stage (reaches prophase of meiosis I)
Chromosomal complement is 4n
Meiosis resumed at ovulatory surge of LH

121
Q

Oocyte development

A

When primordial follicle starts growing, both the oocyte and the follicle increase in size
Oocyte growth is complete at stage of antrum formation
LH peak stimulates GV breakdown: assembly of chromosomes into metaphase plate
During telophase first polar body is extruded: minimal cytoplasm
Oocyte enters second meiotic division: ovulation stage for most mammals

122
Q

Dogs

A

Oocyte ovulate at prophase I- before resumption of meiosis I

Sperm penetration occurs at a stage earlier than ovulation in most other species

123
Q

Cytoplasmic Maturation

A

Apart from nuclear maturation, cytoplasmic changes are necessary
Depends on close association between oocyte and corona radiata cells: cytoplasmic projections through zona pellucida
exchange of molecules and metabolites-helps prep for ovulation
Brake and start up meiosis depends on this communication

124
Q

Ovulation

A

Oocyte and cumulus mass moved into infundibulum of uterine tube by fimbria
Fertilization occurs in ampulla of uterine tube
Short window of fertilizability
Cumulus cells expand so they can be fertilized

125
Q

Sperm Transit

A

Sperm gain ability to fertilize during epididymal transit
Sperm move from site of deposition to uterine tube within minutes due to contractions of female tract
Many millions, or billions, of sperm ejaculated
About a thousand reach the uterine tube
Tens to hundreds present for fertilization

126
Q

Functional Sperm Reservoir

A

Where sperm hang out waiting for an oocyte to fertilize
Isthmus of uterine tube near uterotubal junction
Sperm adhere to tubal epithelium: intimate junction with cell membrane interaction
Adherent sperm have prolonged lifespan (oocyte has short lifespan)
Sperm are released at time of ovulation

127
Q

Capacitation

A

Biochemical changed required in female tract before sperm are capable of fertilization: removal of seminal plasma components, interaction with female secretions
Changes in membrane cholesterol, glycosaminoglycans (membrane fluidity)
Tyrosine phosphorylation
Sperm becomes capable of undergoing acrosome reaction
Hypermotility
Oocyte receptor expression

128
Q

Acrosome reaction

A

Usually occurs upon contact of sperm with zona pellucida (in at least some species during cumulus penetration)
Fusion of sperm plasma membrane with outer acrosomal membrane
Extensive vesiculation over surface of sperm and acrosome
Calcium dependent
Allows orderly release of acrosomal enzymes

Acrosome enzymes are in viscous medium: can act sequentially

129
Q

Penetration of zona pellucida

A

Sperm migrate between cumulus cells
Attach to and migrate through zona pellucida
Fusion of sperm and oocyte membrane

Zona pellucida has 3 major proteins: ZP3 is specific binding site for sperm, mediated by oligosaccharides
Only acrosome-intact sperm bind to zona
Sperm motility and enzymes required for zonar penetration

130
Q

Gamete fusion

A

Sperm goes through cumulus and ZP and is in space between ZP and membrane of oocyte: fuse here
Oocyte membrane is less species-specific in binding than ZP
Completion of acrosome reaction is required before sperm can fuse with oocytes
Fusion involves postacrosomal sperm membrane- becomes fused with oolemma

131
Q

Blocks to polyspermy

A

Mainly at level of ZP

Oocyte cortical granules released into perivitelline space- extensive reorganization of ZP structure

132
Q

Fertilization

A

Oocyte completes meiosis and expels second polar body
Remaining maternal (haploid) chromosomes are enclosed in pronucleus
Sperm nuclear envelop disintegrates- DNA decondensation
New envelope: male pronucleus
Male and female pronuclei migrate to cell center
Nuclear envelopes disperse
Intermixing of chromosomes occurs
Chromosomes aggregate in prophase of first cleavage division
Proximal centriole of sperm forms one of the zygotes centrioles

133
Q

Early Development

A

Several mitotic divisions
Early divisions occur without increase in cell mass (cleavage)
Metabolic support provideed by maternal secretions
Zygotic protein synthesis begins at 2 to 16 cell stage depending on species

134
Q

Development stage

A 
Ootid
Zygote
Morula
Early blastocyst
Hatching blastocyst
Hatched blastocyst
135
Q

Migration to uterus

A

Early cleavage occurs in uterine tubes

Zygote reaches uterus in about four days in cows and most other species but longer is horses and dogs

136
Q

Tubal migration in mare

A

Only fertilized zygotes transported through uterine tubes

Zygote probably responsible for transport by secretion of PGE2

137
Q

Hatched Blastocyst

A

Increased fluid in the blastocele
Proteolytic enzymes from the trophoblast
Blastocysts contraction

138
Q

Important early events

A

Development inside zona pellucida
Hatching from ZP
maternal recognition of pregnancy
Formation of extraembryonic membranes: yolk sac, amnion, chorion, allantois

139
Q

Maternal recognition of pregnancy

A

Critical process in which mother “recognizes” she is pregnant
Major consequence is to prolong period of function of corpus luteum
Transition from cyclic to pregnant state

140
Q

Maternal recognition of pregnancy major strategies

A

Anti-luteolytic:
diversion/inhibition of PGF2a secretion
Luteotropic:
maintain CL

141
Q

Maternal recognition of pregnancy in Ruminants

A

After hatching from ZP, blastocyst elongates very rapidly- contacts most of uterine luminal epithelium
Trophoectoderm produces interferon tau- IFNt
Inhibits oxytocin receptor synthesis
Inhibits prostaglandin F2a
Stimulates endometrial glands

Prevents luteolysis: makes CL lifespan several months

142
Q

Maternal recognition of pregnancy in Swine

A

Blastocyst produces estradiol
Estradiol changes direction of PGF2a secretion by endometrium: from basal (in blood stream) to apical (into uterine lumen)
PGF2a is inactivated in lumen (so CL persists)

143
Q

Maternal recognition of pregnancy in Horses

A

Pregnant and non pregnant cycle similar for first 14 days
Suppression of PGF2a release in pregnant mares
-mechanism not completely understood
-embryo mobility
-pre-implantation factor

144
Q

Pregnancy Physiology

A

Fertilization in uterine tube
Embryo enters uterus around 6 days after fertilization (transport depends on PGE2)
Unfertilized oocytes not transported through uterine tube

145
Q

Mobility Phase

A

Equine embryo migrates through both uterine horns and body several times a day (up to 18 horn changes per day)
Movement is mediated by uterus
Movement is maximal around days 10-12
Prevention of movement results in pregnancy loss

146
Q

Embryo Capsule

A

Unique to equids
Polysaccharide-rich membrane between trophoectoderm and ZP
Forms soon after embryo reaches uterus
Probably responsible to preserving round shape of embryo and maintaining some rigidity, necessary for uterine migration
Disappears after day 23

147
Q

Maternal recognition of pregnancy in Llama

A

Almost all pregnancies in left uterine horn

PGF2a synthesis or release is inhibited, but mechanism is not known

148
Q

Chorionic gonadotrophins

A

eCG: Horses, Chorionic girdle-endometrial cups
hCG: Human, very early: luterotrophic
Placental lactogen/pregnancy-associated glycoproteins: Ruminants

149
Q

Placenta

A

Temporary organ providing support and protection for developing embryo/fetus
Maternal and fetal components
Metabolically active

150
Q

Placental Origin

A

Trophoblast

Allantoic cavity originates from here as well?

151
Q

Placental General Structure

A 
Chorion- outermost layer
Amnion 
Allantois
Yolk sac
Umbilical cord
152
Q

Chorion

A

Outermost layer

153
Q

Amnion

A

Cavity immediately surrounding embryo/fetus

154
Q

Allantois

A

Cavity originating as outpouching of hindgut

Continuous with urachus

155
Q

Placental classification

A

Shape
Degree of invasiveness
Intimacy of attachement
Nature of fetal placental vasculature

156
Q

Placental shapes

A

Diffuse (horse, pig, camelid)
Cotyledonary (cow, sheep, goat)
Zonary (dog and cat)
Discoid (human, mouse)

157
Q

Epitheliochorial

A

Intact membranes both sides
Horse, pig
No erosion of baby side

158
Q

Syndesmochorial

A

Fetal-maternal synctium
Sheep (cow)
Some cells on maternal side fuse together to form syncytium

159
Q

Endotheliochorial

A

Dog and car

Chorion eats through maternal epithelial

160
Q

Hemochorial

A

Human, mouse, guinea pig

161
Q

Adeciduate

A

Horse, pig, ruminants

162
Q

Deciduate

A

Dog, cat, human
When baby is born and placenta shed, some maternal tissue is lost
like deciduous tree

163
Q

Bovine Placenta

A

Cotyledonary, chorioallantoic, epitheliochorial, and syndesmochorial, adeciduate (qualified)

Amniotic plaques
Allantoic calcification mineralization

164
Q

Equine Placental

A

Diffuse, chorioallantoic, epitheliochorial, villous (microcotyledonary, adeciduate

165
Q

Canine Placenta

A

Zonart, chorioallantoic, endotheliochorial, deciduate

Marginal hematoma
Yolk sac

166
Q

Placental Hormone Production

A 
Progesterone
Estrogen
Relaxin
Placental lactogen
Chorionic gonadotrophin
Prolactin
167
Q

Fetal Fluids

A

Protection
Nutrient reservoir (fetus continually swallows fluid)
Water reservoir

168
Q

Maintenance of Pregnancy

A

Progesterone (or progestogen) is an absolute requirement for mammalian pregnancy
Where does the progesterone come from? Ovary and placenta

169
Q

Progesterone in Pregnancy

A 
C21 steroid
Progesterone or prostagens essential for maintenance of pregnancy in mammals
Placental development and function
Myometrial quiescence
Cervical closure
Immune mediation
170
Q

Physiology of Parturition

A

Studied mainly in sheep
To a lesser extent in laboratory species, non human primates
Understanding depends on fragmentary knowledge and extrapolation

171
Q

Trigger for Parturition

A

Fetal hypothalamic-pituitary-adrenal axis
Sustained fetal hypoxemia in late pregnancy
Placental adequacy, rapidly growing fetus
Fetal maturation
CRH->ACTH-> Cortisol
High cortisol levels: highly bound;rapidly metabolized; cortisol receptors

172
Q

Elevated Fetal Cortisol

A

Final maturation of fetal lung (mediates release of surfactants here), kidneys, brain
Induces P450 enzymes: 17a-hydroxylase and C17-20lyse
Progesterone-Androgens
Increased production of prostaglandins by placenta and uterus

173
Q

Prostaglandin F2a

A

Further stimulates fetal secretion of CRH
Stimulates P450 system
Myotonic

174
Q

Estrogen

A

Synergistic with relaxin
Breaks down disulphide bonds in collagen: softening of ligaments and cervical ripening
Relaxin: ovary (cow), Placenta (mare)

175
Q

Fergusson’s Reflex

A

Pressure in cervix/vagina
Increased secretion of oxytocin (positive feedback)
Urge to push

Fetus moves into birth canal

176
Q

Cervical dilation

A

Starts at vaginal end
Cone-shaped
Progressively shorter
Ultimately completely obliterated

177
Q

Neonate

A

Adjustment to postnatal life
Respiration
Circulatory changes: fetal adaptation that are harmful in postnatal life
Thermoregulation

Fetus practices breathing amniote to strengthen muscles

178
Q

First Breath

A

Fluid compressed from lung and airway during vaginal delivery
Amniotic fluid also absorbed from lung into pulmonary circulation
Cold, touch, sound stimulate respiration
Central chemoreceptors increase respiratory dive- stimulated by hypoxia, hypercarbia

179
Q

Initial breathing

A 
high negative inspiratory pressure: 
-airway resistance
-fluid in airways
-surface tension in alveoli
Production of surfactant by type II pneumocytes:
-cortisol
-epinephrin
-alveolar distension
180
Q

Control of ventilation

A

Respiratory rhythm generated in ventrolateral medulla: modulated by central chemoreceptors (O2, pH, CO2)
Peripheral chemoreceptors (aortic and carotid bodies) are functional bu silent (high O2 in neonate): adaptation over 48h
Initial response to hypoxia is tachypnea followed by reversion to fetal response

181
Q

Fetal Circulation

A

Oxygenated blood delivered preferentially to brain, myocardium
Returning oxygenated blood: ductus venosus (bypasses liver to vena cava) and foramen ovale (shunted from right to left atrium)
Deoxygenated blood: right atrium, right ventricle, pulmonary artery. Ductus arteriosus deviates 80% to aorta

182
Q

At birth

A

Increased pulmonary blood flow
Removal of placenta and placental circulation
Closure of: foramen ovale (functional and rapid),
Ductus arteriosus (drop in pulmonary pressure, increase in systemic vascular resistance: reverse flow; increased PO2; PGE2 declines),
Ductus venosus (reverse flow)

183
Q

Thermoregulation

A

Heat loss:
-high surface to volume (bodyweight) ratio
-Limited subcutaneous fat for insulation
-evaporative hear loss (wet neonate)
Thermogenesis
-limb movement
-stimulation of brown fat (sympathetic)- triglycerides and free fatty acids

184
Q

Other considerations

A

High body water content (75%)
Hepatic function: gradually increases over first 3 months
Renal function: glomeruli and nephrons present at birth but immature
-lack of osmotic gradient (lack of concentrating ability)
-lower GFR than adult (neonate susceptible to both dehydration and volume overload)

185
Q

Lactation

A

Progesterone, estradiol, prolactin, placental lactogens
Colostrum: immuneoglobulins, immune cells, nutritive value
Milk ejection reflex: sensory input, oxytocin release

Physiology 2 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions