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BVMS Module 5 > Week 1 > Flashcards

Week 1 Flashcards

1
Q

describe the anatomy and function of the hypothalamus?

A 
situated below the thalamus but above the pituitary. with the medulla oblongata caudal 
function - integrator of neurone + endocrine system 
- regulates reproduction 
- the important areas; pre-optic area, media-basal hypothalamus.
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2
Q

what is GnRH?

A

is a releasing hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary.
Prolactin is inhibited when released, regulating negativity.

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3
Q

what is the release pattern of GnRH?

A

pulsatile -

GnRH binds to receptor on gonadrotope cell in AP, but must be pulsatile to have an intraceuller effect.

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4
Q

how is LH and FSH secretion regulated?

A

LH release and synthesis under GnRh regulation

FSH synthesis and release constitutive + under control by peptide regulators: Oestradiol!!

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5
Q

describe the hormone feedback from a release of GnRH?

A

⬆️GnRH = ⬆️LH + ⬇️FSH = oestradiol ovarian peptides ➡️ progesterone androgens causing GnRH surge and less FSH.

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6
Q

describe the general histological arrangement of the ovary?

A

surface epithelium layer, tunica albuginea, medulla, cortex.

ovary derived from oocyte - arrested in diplotene stage of meiosis, completed a fertilisation.

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7
Q

what are primordial follicles?

A

folliculogenesis, primordiale pool - mid late gestations

affected by age, breed, nutrition stage.

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8
Q

name the 5 follicles in the ovary?

A 
primary
secondary 
tertiary
preovulatory
atretic
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9
Q

describe primary follicle?

A

start, becomes cuboidal surrondnded by interstitial fluid, onset of follicular growth.

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10
Q

describe secondary follicles?

A

cell proliferation, often termed ‘prenatal’

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11
Q

describe tertiary follicles?

A

vesicular or ontral
antrum formation as granulosa and theca proliferation .
Gonodropoptin - dependent growth, driven by FSH, strike genesis increasing markers.

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12
Q

describe preovulatory follicles?

A

very enlarged, protruding on ovarian surface, except at hilus, hormones trigger ovulation

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13
Q

describe atretic follicles?

A

fast of majority > 99% sudden death of granuloma cells. Apoptotic process.
early Atresia - necrotic granulosa cells
late atresia - more necrotic granulosa cells.

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14
Q

describe the clinical application of follicle function?

A

manipulation of follicle function, oestrus synchronisation, super ovulation (MOET)

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15
Q

what does luteolysis involve?

A

PGF2a

Oxytocin.

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16
Q

what are neoplasms?

A

granulosa cell tumours

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17
Q

what is follicular devoplemnt?

A

‘ovarian reserve’ and recruitment of primordial follicles.
primordial follicle pools - resting follicles present form birth in females.
devolpment includes: recruitment, follicular grow and ovulation.

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18
Q

what percentage of growing follicles make it to ovulation?

A

1%

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19
Q

summarise the follicular growth in cows?

A

takes 3 months (150 days)
almost all follicles move into atresia death
LH ans FSH levels important in final stages of atrial follicle growth and development.
after recruitment - primary and secondary follicles respond to FSH + early ant rail follicles with response to LH.
Antral follicles produce steroid hormones = acerbate growth

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20
Q

what is the main function of progesterone?

A

synthesed by LH theca cells - converted into androgens

cholesterol uptake by theca cells turns into progestrone.

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21
Q

how is oestradiol produed?

A

androgens from LH theca cells pass through granulosa cells + converted into oestradiol
armature enzyme used for conversion

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22
Q

what is follicular wave growth?

A

non-ovulatory species (one offspring)
small astral follicles become complete FSH-dependent.
but the last follicle becomes LH dependent

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23
Q

what does the last follicle become dependent o and what does this cause?

A

dependent on LH pulse frequency and determines if dominant follicle growth occurs.

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24
Q

why must there be frequent Lh pulses occurring for dominant follicle growth?

A

frequent pulses = max amount of oestradiol produced for follicle growth + ovulate.
final masturation and ovulation.

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25
Q

what causes ovulation of the DF? (dominant follicle)?

A

LH pulse frequency increases,
oestradiol synthesis increases rapidly, including GnRH thus LH/FSH surge occurs
causing ovulation of DF.
follicular phase: oestradiol rise, surge and ovulation

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26
Q

what’s the difference between spontaneous ovulations and reduced/induced ovualitors?

A

spontaneous - rapid rise in oestradiol, with or without onset of lutenization, induces GnRH surge
Induced - a neuroendocrine reflex induces the GnRH

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27
Q

what is cumulus expansion?

A

cumulus cells withdraw from sticky matrix without spermentaoza, need to pernetrate in order to fertilise egg, the oocyte separate fluid in antrum but surrounded by broncos cells

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28
Q

what is the Corpus Luteum?

A

develops from the transforming and proliferating follicle wall cells - CL can secret progesterone during luteal phase.

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29
Q

what is the need for progesterone?

A

negative ffedback on hypothalamus GnRH secretion - suppresses pulse frequency and surge.

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30
Q

what is Luteolysis?

A

CL regression must occur in absents of pregnancy so female can come onto heat and ovulate again

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31
Q

what is active luteolysis?

A

PGF2a causes regression of CL. the endodertrium is large animals produce PGF2a
Ruminants : secretion of PGF2a into uterine vein
: direct uptake of PGF2a into ovarian artery
: arterial supply to CL delivers undiluted PGF2a - CL regresses.

32
Q

what is passive luteolysis?

A

LH, prolactin decline in circulation, CL no longer supported to produce progesterone and regresses.
Progesterone declines rapidly
(occurs in small animals)

33
Q

describe the ovary function?

A

ova devoplment and release

Hormone production and release.

34
Q

what does the ovary consist of?

A

Hilus - attachment site for supporting structures
Vascular zone - usually central
Parenchymal zone - peripheral, ova + hormone production, ovulation

35
Q

how is the mare ovary different?

A 
the regions are reversed, 
The parenchymal zone in central 
Vascular zone is peripheral 
Broad hilus
and a central depression
36
Q

discuss how the ovary is examined?

A 
transrectal palpation (cow and mare) 
Ultrasound - fluid = anechoic = black
soft tissue = echogenic = grey
37
Q

describe pre-ovulatory follicles in mare?

A

atretic follicles regress
cow = 1-2cm
mare 3-5cm
Mare = preovulatoty follicle migrates towards ovulation fossa
soft on palpation, pears shaped in ultrasound

38
Q

explain the luteal phase?

A

corpus haemorrhgium/rubrim

forms a space made by follicle, not palpable, visible = ultrasound,

39
Q

describe CL?

A

Corpus Luteum - occupies space left by follicle, solid structure, echongenus in ultrasound, may contain central fluid (Lacuna),
Produces Progesterone - causes: behavioural changes
; changes to tract.

40
Q

describe ovarian follicles?

A

follicles that contain 1 ovum , grow on surface, fluid filled,
Produce Oestrogen - causes: behavioural changes and
Changes to tract. (allows segment travel)

41
Q

identify the different stages of the oestrus cycle?

A 
oestrus and ovulation 
HEAT = oestrus (standing to be mounted (mating)) 
The Luteal Phase (functional lifespan of CL) Rise in progesterone levels
Follicular Phase (CL regression, start of LH surge, Oestrus begins again)
42
Q

what effect does a increased GnRH Surge cause?

A

during follicular phase, increase in ovarian hormones and a peak in Oestradiol

43
Q

what effect does a decrease in GnRH surge cause?

A

Luteal phase, increase in ovarian hormones OR elevated progesterone levels.

44
Q

what hormone prepare tract for fertilisation?

A

oestradiol

45
Q

what hormone prepare tract for pregnancy?

A

progesterone

46
Q

define Met-oesturs
Di-oestrus
Pro-oestrus

A

1 - same as oestrus
2 - same as follicular phase
3 - leads to oestrus

47
Q

what is the tubular tract?

A

consists of paramesonphric duct, uterine horns, uterine tubes that fuse caudally - uterine body and vagina cervix
joins at urogenital sinus

48
Q

function of uterine tubes?

A

transport sperm proximally + ovum distally
infundibulum - funnel shaped
Ampulla - short proximal section, site of fertilisation
Isthumus - long, narrow, and tubles, opens into uterine horn.

49
Q

function of Uterus?

A

litter producing species - very long uterine horns. pig and cow have very long horns and Dog has short, sheep has a coiled horns like a rams horns, long septum uterus

50
Q

use of intercornual ligaments?

A

dorsal, ventral and useful for manipulation of tract recally

51
Q

what are caruncles?

A

site of membrane faetals - located on endometrium.

concave structure on sheep

52
Q

describe cervix?

A

function - sphincter - controls passage between uterus and vagina.

53
Q

When is the sphincter in the cervix open?

A

during oestrus + parturition, passage of semen, lubricant mucous

54
Q

when is the sphincter in cervix closed?

A

during luteal phase + pregnancy, increased tone and sticky mucous.

55
Q

describe the structure of vagina and surrounding structures?

A

vagina - cervix to urthral orifice = long
epithiuelm affected by ovarian hormones, vaginal cytology
Vestibule - urthral orficie to vulva - short

56
Q

describe the Bitch urethral orifice?

A

raised above vestibular floor, depression on either side, urinary catheterisation = difficult!!

57
Q

describe the cow urethral orifice?

A

suburethral diverticulum, care when passing catheter.

58
Q

describe the Clitoral fossa?

A

contains the clitoris, (homologous to penis)
Mare - contagious equine metritis swabs
Bitch - vestibule bulbs, erectile tissue, contribute to ‘tie’ at mating, vestibule glands - mucous production.

59
Q

describe the vulva?

A

two skin layers covered by labia,
during oestrus; Bitch - swollen
cow - bulling sring
mare - inversion of clitoris

60
Q

name the supporting structure of the female reproductive system?

A

Broad ligament - suspends tract
Mesovarium - supports ovary
Mesometrium - uterus and cdrvix
Mesosalphinx - uterine horn and ovary sac

61
Q

explain the mesosalphinx?

A

Fold of tissue, forms ovarian bursa,
Cow/sow - shallow and open
Mare - infunibulm attached at ovulation fossa
Bitch - fat filled, slit like opening, Bursa and ovary BOTH removed in bitch spay

62
Q

what are the 3 main arteries supplying the ovary?

A

ovarian artery - direct form aorta, high pressure, ovary, uterine tubes, uterus
uterine artery - low pressure, branch from iliac artery, supplies uterus, forms arterial arcade,
vaginal artery - branch of internal or external iliac artery, supplies coulda tract

63
Q

explain the venous supply ovaries?

A

mirrors the arterial supply.

64
Q

explain the lymphatic drainage and nerve supply for the ovaries?

A

lymph - ovaries and cranial tract = aortic + medial like node
nerves - innveraiton PS = fibres from pelvic nerves
S = follows partial blood vessels.

65
Q

describe the oestrus cycle in the cow?

A

21 days
LH pulsatility changes depending on progesterone concentrations.
during - 2-3 follicles (DF) are selected, each follicle wave emerges following FSH rise + DF selection, LH pulsalitiy determines survival growth + oestradial production from selected DF

66
Q

Describe the mare oestrus cycle?

A

21 days
similar to cow rise in FSH, emerging of follicle wave, dominant follicle selection during FSH decline, mid cycle DF selected.
oestrus 5-7 days due to high oestradial.
LH peaks after ovulation,
14 day luteal phase 7 day oestrus phase by PGF2a

67
Q

describe the graph of the mare oestrus cycle?

A

oestrus lasts for 7 days, with an oestrdaiol surge causing an LH surge after ovulation - causes rapid lutinisaiton and oestrus ends - Rapid lutinisaiton + increase in production, leading to an adrupt decline in lutrolysis. day 15 oestrus starts again and ovulation occurs 1-2 days before end

68
Q

Describe the oestrus cycle in ewe?

A 
17 days 
ovulation at end of cycle 
14 day luteal phase 
2-4 day follicle wave per cycle 
multiple ovulation service last two cycles.
69
Q

describe the graph of the ewe oestrus cycle?

A

Oestradiol rise at start with oestrus and progesterone/LH levels low.
day 3 LH surge occurs and 14 day luteal phase with a slow increase in progesterone. with a abrupt decline due to PGF2a
levels of oestrdial fluctuate through out the cycle

70
Q

what regulates seasonality??

A

The pineal gland - releases melatonin + controls temperature and nutrition.
Pineal gland positioned just above Thalamus.
melatonin is released under hours of darkness. reflects change sin day enter due to light exposure.

71
Q

how does melatonin onset the breeding season?

A

melatonin is interpreted by hypothalamus and changes response to GnRH neurones to oestrdaiol.
breeding season onset =less negative feedback of oestrdaiol - GnRH + LH pulses become more frequent
Ewes think days become shorter which triggers 1st ovulation of breeding season due to less sunlight in a shed.

72
Q

what is puberty defined by?

A

first ovulation, first oestrus, first pregnancy

depends on sex, species, BW gain, season, group size.

73
Q

summarise the hormonal + follicular events for puberty?

A

increase in GnRH/LH pusalilty FSH
transient FSH rise + follicle weaves begin
strong NEGATVIE feedback of oestrdoail on GnRH secretion
as puberty approaches less negative feedback by oestrdaiol, more LH pulses - follicler oestrdiaol production increases.

74
Q

what neurone is the over-all integrator regulate GnRH release?

A

Kiss-1 neuron

75
Q

describe the bitch oestrus cycle?

A

very long inter-oestrus ineterval - 7 months Monooestrus
Pre-oestrus 7-9 days
Oestrus 7-9 days
metoestrus - 2+ months
anooestrus - 2-5 months
Very long luteal phase - onset of progesterone production form lutierising surge until collided causes the LH surge in bitch.

76
Q

describe the cat oestrus cycle?

A

induced ovulater, mating causes endocrine reflex causing GnRH surge (vaginal stimulation)
cats always on heat!
Oestradiol rises regularly during breeding season, progesterone rises when CLs develop,

BVMS Module 5 (4 decks)

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