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Anatomy And Physiology > Reproductive System > Flashcards

Reproductive System Flashcards

1
Q

Why is meiosis called reduction division

A

Because total number of chromosomes in the cell is halved

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2
Q

Define spermatogenesis

A

To create spermatozoa

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3
Q

True or false

Spermatozoa are created continuously throughout life

A

True

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4
Q

Describe spermatogonia

A

Large cells on the outer most parts of the seminiferous tubules (germinal epithelium)

Is diploid

First divides by mitosis into one spermatogonia and one primary spermatocyte (both still diploid)

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5
Q

Describe the primary spermatocyte

A

First duplicates it’s DNA to produce double chromosomes

Then divides by meiosis to produce 2 secondary spermatocyte (both haploid)

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6
Q

describe the secondary spermatocyte

A

Divides by mitosis or meiosis depending on source

Two secondary spermatocyte each divide into two haploid spermatids (4 spermatids total for one primary spermatocyte)

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7
Q

During spermatogenesis, where does the cell move

A

Closer towards the lumen of the seminiferous tubules

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8
Q

What are spermatids supported by until they develop flagellum

A

Supporting cells

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9
Q

What are spermatids considered once they develop flagellum

A

Spermatozoa

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10
Q

When the spermatids are free in the lumen of the seminiferous tubules, where are they transported for maturation

A

The epididymis

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11
Q

What happens if spermatids are not ejaculated

A

They die and get absorbed by the lining of the epididymis

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12
Q

Name and describe the parts of a sperm cell

A

Head: contains a nucleus with the chromosomes covered in a cap-like structure called the acrosome (contains enzymes to help penetrate ovum)

Body/mid piece: contain mitochondria to create ATP to power flagellum

Flagellum: contractile proteins to enable movement

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13
Q

describe the sex chromosomes of a sperm cell vs a ova

A

Sperm cell: a male with two copies of the sex chromosomes, XY, the haploid sperm cell can be either X or Y

Ova: a female with two copies of the sex chromosomes, XX, the haploid ova can only be X

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14
Q

Who determines the sex of the offspring

A

The male, since they contribute either an X or a Y chromosome

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15
Q

What do you look at with a semen evaluation and what is it used for

A

Typically used for large animal medicine to determine fertility

Look at:
Volume produced
Concentration of sperm in semen 
Motility of sperm
Live:dead sperm ratio
Morphology of sperm (deformities or defects)
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16
Q

What are primary defects of sperm

A

Occur during spermatogenesis and include heads that were doubled, misshaped, enlarged or shrunken and mid pieces that are kinked, twisted or doubled

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17
Q

What are secondary defects of sperm

A

Occur at any time from storage in the epididymis until the slide is made. Includes headless tails, tailless heads, and bent tails

LESS serious

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18
Q

What has the greatest effects on fertility

The total number of normal sperm or the percentage of abnormal sperm

A

To total number of normal sperm

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19
Q

As much as ____% of spermatozoa will be abnormal in a healthy animal

A

10-20%

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20
Q

Define oogenesis

A

To create oocytes

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21
Q

True or false

Oogenesis is a continuous process

A

FALSE

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22
Q

Most of the development of primary oocytes occurs ___ birth

A

Before birth

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23
Q

True or false

Females have a predetermined number of primary oocytes that she will have for life and will not make any more

A

True

Predetermined before birth

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24
Q

Primary oocytes are immature, and only develop to mature ova when the follicle they are resting in ___

A

Develops to maturity

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25
Q

Follicles mature in response to

A

FSH

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26
Q

How many follicles develop in animals that have only one offspring, why?

A

One follicle at a time

Because the dominant follicle suppresses the development of other follicles

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27
Q

How many follicles develop in animals having more than one offspring

A

Multiple

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28
Q

Maturation of a diploid primary oocyte involves it undergoing meiosis to produce a

A

Haploid ovum

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29
Q

Describe the process of oogenesis and maturation of a primary oocyte

A

The primary oocyte duplicated each chromosome to have double sets

The primary oocyte then divides by meiosis (1), the duplicated chromosomes pair up and then separate into 2 haploid secondary oocytes with duplicated chromosomes

The secondary oocytes divide by meiosis (2) to create haploid cells with single chromosomes. After both secondary oocytes divide, only one new division creates one ovum, and the rest are 3 polar bodies which is a remnant of the unwanted nuclear material which get broken down by the body

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30
Q

How many ova a created for each primary oocyte

A

1 ova and 3 polar bodies

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31
Q

What do the testes consist of

A

A mass of seminiferous tubules surrounded by a heavy fibrous capsule

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32
Q

What are the testes the site of

A

Spermatogenesis

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33
Q

What are the 3 main functions of testes

A

Spermatogenesis
Hormone production
Delivery of spermatozoa to the female

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34
Q

Describe hormone production in the testes

A

Interstitial/Leydig cells: stimulated by LH from the anterior pituitary, release androgens (mainly testosterone) responsible for male secondary sex characteristics

Sertoli cells (support cells): produce small amounts of estrogens stimulated by FSH.

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35
Q

What do Sertoli cells also do

A

These are the “nurse cells” for maturing spermatids -help shield the spermatocyte from attack by the body’s immune system

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36
Q

Describe the structure of the testes from innermost later to the outermost layer

A

Seminiferous tubules: site of spermatogenesis -interstitial cells located in connective tissue between the tubules

Capsule: encloses the testes in a fibrous connective tissue capsule called the tunica albuginea. Protects and supports soft contents of the testes -gives shape

Vaginal tunics: double layered sleeve of peritoneum which lines the scrotum and inguinal canal. Thin Inner layer (visceral tunic) tightly adhered to the testes and spermatic cord. Thick outer layer (parietal tunic) forms a fibrous sac around the testes and spermatic cord (lines the Corium) these tunics are separated by a small amount of fluid

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37
Q

Describe the descent of the testes into the scrotum

A

Testes begins in the abdominal cavity near the kidneys

Under the influence of testosterone, they move caudally through the inguinal canal in the peritoneum

Guided by the gubernaculum: a fibrous cord that extends from the testis to the scrotum (fails to lengthen or actively shortens to pull testis down)

As the testis pushes through the peritoneum of the inguinal canal, it creates the vaginal tunic

Eventually completely passes into the scrotum and descent in complete

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38
Q

Describe when testes drop in different species

A

Ruminants: prior to birth
Pigs: just before birth
Horses: around time of birth
Cats/dogs: shortly after birth (days to 8 weeks)

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39
Q

What is the scrotum and what does it do

A

A sac of skin which houses the testes

Functions to thermoregulate and provide a favourable environment for production of sperm

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40
Q

How does the testes thermoregulate

A

The testes is raised and lowered via the cremaster muscles depending on environmental temperatures.

In hot temperatures the muscle relaxes and the testes hangs low

In colder temperatures the muscle contracts and raises the testes

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41
Q

What is the spermatic cord

A

A group of structures which extends proximally from the testis through the inguinal canal

Includes: blood and lymphatic vessels, nerves, and the vas deferens covered in an extension of the vaginal tunic

Links the testes with the rest of the body

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42
Q

Describe the cooling mechanisms of the blood vessels within the testes

A

The pampiniform plexus

A complex of veins wrapping around the arteries of the testes

Veins carry cooler blood than arteries since it just returned from the skin, heat transfer occurs to cool arterial blood and warms the blood in the veins returning to the body.

It is an example of a countercurrent exchange

Helps keep the testes at suitable temperatures for spermatogenesis (cooler than body temp)

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43
Q

What is the epididymis

A

An elongated highly coiled organ that lies next to the testes and receives immature sperm from the seminiferous tubules

It is the site of maturation for sperm

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44
Q

Where does the head, body and tail of the epididymis attach

A

The head attaches to the same end of the testes that the spermatic cord enters

The body parallels the long axis of the testis

The tail continues as the ductus deferents which doubles back along the body of the epididymis to the region of the head and becomes part of the spermatic cord

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45
Q

What moves sperm into the ductus deferens at ejaculation

A

Peristaltic contractions

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46
Q

True or false

The epididymal duct is very long

A

True

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47
Q

What is the ductus deferens/ vas deferens

A

A muscular tube that transports spermatozoa from the tail of the epididymis to the ejaculatory ducts at ejaculation

Leaves the tail of the epididymis and passes through the inguinal canal as part of the spermatic cord and eventually loops around a ureter as it continues past the bladder towards the urethra

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48
Q

What happens to the ductus deferens at the bladder

A

Thickens to form the ampulla in some species

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49
Q

What happens to the ductus deferens at the inguinal ring

A

Turns caudally separating from the vascular and nervous parts of the spermatic cord

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50
Q

What is the inguinal canal

A

In the abdominal wall, it extends from the deep inguinal ring to the superficial ring

The spermatic cord passes through this ring and the testes pass through it on its descent

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51
Q

What do the ampullae, vestibule glands, prostate glands and bulbourethral/Cowper’s gland all have in common

A

Produce the greater part of the ejaculate

Serve as transport for spermatozoa, a nutrient source, and a buffer against the acidity of the female genital tract

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52
Q

What is the ampullae

A

A glandular enlargement of the terminal parts of the ductus deferens that contributes fluid to semen

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53
Q

What is the vesticular gland

A

Paired and positioned at the neck of the bladder, join the ductus deferens to form an ejaculatory duct into the pelvic urethra

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54
Q

What is the prostate gland

A

Present in all domestic species, it more or less completely surrounds the pelvic urethra

Consists of a body (seen on outside of urethra) and a glandular layer in the urethral wall

Produces alkaline secretion that gives semen its odour

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55
Q

What is the bulbourethral (Cowper’s) Gland

A

Paired glands present in all domestic species except for the dog (lies near the bulb of the penis)

Secretes a mucus containing fluid that helps lubricate the urethra

Each gland has an excretory duct which joins the urethra

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56
Q

What is the anatomy of the penis

A

Specialized and complex organ that surrounds the terminal part of the urethra and functions in both reproductive and urinary systems

Divided into: glans/pre extremity, body or main portion, and two cura or roots (connective tissue attachment of the penis to the pelvis)

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57
Q

What are the two classifications of types of penises based on the amount of connective tissue present

A

Fibroelastic: (pigs and ruminants) High levels of connective tissue making them more firm even when not erect, non expandable, often contain a sigmoid flexure

Musculocavernous: (canine, feline, horses) lots of erectile tissue and little connective tissue so erection increases length and diameter

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58
Q

How is the cat’s penis modified to aid in mating

A

Cats have cornified “hooks” to improve attachment/hold while mating

Explains why queens scream when toms pull out

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59
Q

Describe the penis of the dog

A

Has an os penis (bone within the penis) and the bulb of the glands that causes dogs to “tie” after mating

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60
Q

Explain the “tie” when two dogs mate

A

Occurs when muscles of the vagina and vulva contract around the swollen bulb of the glands (bulbus glandis)

Causes male and female to be locked together for 15-20 minutes

Not painful -dogs will stand tail to tail until release

Improves conception rates

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61
Q

What is a sigmoid flexure

A

S-shaped curvature in the non-erect penis of the bull/ram/boar since they have fibroelastic penises

Due to their inability to swell/enlarge during erection, the sigmoid flexure instead straightens in response to increased blood pressure and the penis extends

Once erection is done, the retractor penis muscle pulls it back into normal resting S shape

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62
Q

What stimulates erection of the penis

A

Parasympathetic nervous reflex in response to sexual stimulation

Primarily pheromones

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63
Q

How does erection work

A

The penis fills with blood due to Dilation of the arteries and compression of the venous return due to the ischiocavernous muscles pressing the root of the penis cells against the brim of the pelvis

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64
Q

What are the two stages of ejaculation

A

Movement of spermatozoa and fluids from accessory glands to pelvic portion of the urethra (bladder closes to prevent semen from entering the bladder)

Rhythmic contractions of urethra pump semen out and into the female

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65
Q

What is the prepuce

A

Invaginated fold of skin surrounding the free extremity of the penis

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66
Q

What are the main muscles of the male genitalia

A

External cremaster muscle

Urethral muscle

Bulbospongiosus muscle

Ischiocavernous muscle

Retractor penis muscle

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67
Q

What does the external cremaster muscle do

A

Passes through the inguinal canal running beneath the parietal vaginal tunic, raises and lowers the testes depending on temperature

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68
Q

What does the urethral muscle do

A

Surrounds the pelvic portion of the urethra where it transports urine or seminal fluid distally by peristalsis

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69
Q

What does the bulbospongiosus muscle do

A

Continues the action of the urethral muscle in emptying the returns by peristaltic contractions

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70
Q

What does the ischiocavernous muscle do

A

When these muscles contract they pull the penis against the pelvis aiding erection by shutting off much of the venous drainage from the penis

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71
Q

What does the retractor penis muscle do

A

Following erection, this pulls the flaccid penis back into the prepuce

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72
Q

What artery supplies the testes

A

Testicular artery, branches directly from the aorta

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73
Q

True or false

It is easy to use local anesthetic in the scrotum due to extensive venous network

A

True

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74
Q

What does the pudendal artery supply

A

Penis, bladder, urethra and accessory sex glands In the bull, ram, boar and dog

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75
Q

What artery supplies the penis of the horse

A

Obturator artery and the external pudendal artery

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76
Q

Nerve supply to the testes is mainly supplied via the

A

Autonomic nervous system

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77
Q

Scrotal sacs are pendulous in

A

Dogs horses and ruminants

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78
Q

Scrotal sacs are not pendulous and located just central to the anus in

A

Cats and pigs

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79
Q

Vesticular glands are not present in

A

Cats and dogs

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80
Q

Describe a canine penis

A

Musculocavernous
Has an os penis
Glands penis (free end): divided into long part of the gland distally and bulbus glandis (engorges at erection and along with vestibular glands bulbs of the bitch is responsible for the “tie”)

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81
Q

Describe the feline penis

A

Musculocavernous
Directed caudoventrally (most others are cranioventrally)
Gland penis is covered with cornified, epithelial, proximally projecting spines

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82
Q

Describe the equine penis

A

Musculocavernous

Upon erection it expands in all dimensions so much, it deposits semen directly at the cervix

Has short urethral process that form a diverticulum dorsal to the urethra which collects smegma and debris to form a “bean” (need routine sheath cleaning)

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83
Q

What is smegma

A

Secretion of sebaceous glands consisting mainly of dead epithelial cells

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84
Q

Describe the bovine penis

A

Fibroelastic

Has sigmoid flexure

Twisted glans penis as well as a free extension of the urethra called the urethral process

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85
Q

Describe the porcine penis

A

Fibroelastic with sigmoid flexure

Twisted glans penis in “corkscrew” configuration

Prepuce: has preputial diverticulum opens dorsally to the prepuce (decomposing urine and debris collects here and is responsible for odour of pigs)

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86
Q

What is cryptorchidism

A

Failure of one or both testicles to descend (remain in abdominal cavity or inguinal canal)

May produce hormones but usually no sperm (from being kept too warm)

Hereditary in equine and porcine

Animal may be referred to as “ridgling” or “rig”

May be hereditary in dogs and cats

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87
Q

What are testicular tumours

A

Sertoli cell tumors produce estrogen, changes in behaviour and feminization occurs (pendulous prepuce, mammary gland development and milk production)

The penis and opposite testes will atrophy and other male dogs may be attracted to the animal

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88
Q

Why is castration done

A

To control sexual behaviour and aggression

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89
Q

What is an open castration

A

The scrotum and parietal tunic are incised and the testicle is removed

Suture is made to close off the communication to the abdominal cavity

90
Q

What is a closed castration

A

Scrotum is incised, tunic is left intact

Vessels are ligated by placing sutures around the outside of the parietal tunic

Testicles are removed within their tunics

91
Q

What are the risks for both open and closed castration

A

Infection
Herniation
Hemorrhage

92
Q

Open castration Carry a greater risk of

A

Herniation and infection

93
Q

Closed castration carry a greater risk of

A

Hemorrhage because it is difficult to tightly tie off vessels

94
Q

What is a inguinal hernia

A

If the internal ring and canal are too relaxed, a loop of intestines may pass through the canal into the scrotum producing an inguinal hernia

Hereditary/more common in horses and pigs

95
Q

What can happen to the prepuce with a stricture of the preputial orifice

A

Inability to extend the penis from the prepuce

96
Q

What can also go wrong with the prepuce

A

Adhesions, tumors, hematomas, and congenitally short penis or retractor penis muscles and prolapse of the prepuce

May need circumcision to correct

97
Q

What problem is common with prostate

A

Benign prostatic hypertrophy is common in older intact males

Can develop prostatic tumors or abscesses

98
Q

What is the reproductive tract of the female suspended in

A

In a sheet of peritoneum called the broad ligament attached to the dorsal body wall

Carries blood vessels, nerves and lymphatics to the reproductive organs

At the cranial ends is the suspension ligaments of the ovary

The round ligament of the uterus is located within the broad ligament and extends caudally from the uterine horn to the inguinal canal

99
Q

What are the subdivisions of the broad ligament

A

Mesovarium: cranial part of the broad ligaments which supports the ovary

Mesosalpinx: supports the oviducts

Mesometrium: supports the uterus

100
Q

What is the primary organ of reproduction for females

A

The ovaries

101
Q

What are the functions of the ovaries

A

Production of ova

Hormone production

102
Q

What hormones do the ovaries produce

A

Estrogen: produced by developing follicles (physical and behavioural changes for breeding/pregnancy)

Progestins: primarily progesterone produced by the CL (prepares uterus for implantation and maintains pregnancy)

103
Q

What two hormones affect the ovarian cycle

A

FSH: stimulates primary oocyte to develop into a follicle

LH: Stimulates ovulation

104
Q

What are uniparous species

A

One oocyte released per cycle and one offspring

Horse/cows/humans

105
Q

What are multiparous species

A

Multiple oocytes released per cycle to have a litter

Dog/cat/pig

106
Q

What are the stages of the follicle

A

Primordial follicle

Primary follicle

Growing follicle

Mature follicle

Ovulation

Corpus luteum

107
Q

Describe the first step of the ovarian cycle: primordial follicle

A

Immature oocyte surrounded by a single layer of follicular cells

Many found in the ovary

Some may develop into a primary follicle

108
Q

Describe the second step of the ovarian cycle: primary follicle

A

Activated by FSH, the primordial follicle begins to develop further, follicular cells change shape from flat to cuboidal (called granulosa cells) Now called a primary follicle

Only a few follicles respond to the FSH wave Called follicular recruitment/activation

Will then continue to develop and is called a “growing follicle”

109
Q

What happens to other follicle that begin to develop in uniparous species

A

Only one follicle will become dominant and it will prevent the others from being able to develop and they will regress and degenerate

Called follicular atresia

110
Q

Describe the third step of the ovarian cycle: growing follicle

A

Follicular cells continue to multiply and create several layers around the oocyte

Now called a secondary follicle (with several layers)

This secondary follicle now produces estrogen in prep for breeding and pregnancy

111
Q

What happens as the follicle increases in size

A

Estrogen levels increase

Develops a fluid filled space between the oocyte and the granulosa cells (antrum)

Primary oocyte divides to produce a secondary oocyte

112
Q

Describe the fourth stage of the ovarian cycle: mature follicle (graafian follicle)

A

Large blister like structure in the ovary

At maximum estrogen production this stimulates LH release

The oocyte is now sitting in a stack of granulosa cells called a cumulus oophorus and is covered by a thin layer of granulosa cells called the corona radiata which acts as a barrier to insemination

113
Q

Describe the fifth stage of the ovarian cycle: ovulation

A

Rupture of the follicle in response to the LH surge -releases secondary oocyte/immature ovum

Follicle fills with blood which clots and form the corpus hemorrhagicum

114
Q

Describe what stimulate ovulation in most species, spontaneous ovulaters and induced ovulaters

A

Most: LH levels

Spontaneous: ovulate at predetermined times

Induced: stimulation by copulation (cats/ferrets/rabbits)

115
Q

Describe the sixth stage of the ovarian cycle: the corpus luteum

A

Continued levels of LH change the corpus hemorrhagicum: granulosa cells continue to multiply and it develops into a large yellow mass of cells called the corpus luteum (yellow from blood)

The corpus luteum produces progestins (progesterone) to prep for implantation and pregnancy

If the LH levels do not maintain (no fertilization/implantation) the corpus luteum will regress

116
Q

Describe the oviducts

A

Paired convoluted tubes that extend from the tips of the uterine horns

They capture and transport ova from the ovary to the uterus and serve as the location for capacitation and fertilization

Composed of smooth muscle lined with highly folded mucous membranes and covered in cilia (aid it moving ova and sperm)

117
Q

Describe how the oviducts are connected to the ovaries

A

NOT actually attached to the ovary

The oviduct has a funnel shaped end (called the infundibulum) that is near the ovaries that catches the ovulated oocyte

118
Q

How do ectopic pregnancies occur

A

Ovulated oocytes are caught in the in infundibulum but occasionally oocytes can sneak out of the infundibulum and implant somewhere in the peritoneal cavity (usually disintegrate but can cause implantation of a fertilized ovum elsewhere)

119
Q

Describe the uterus

A

A hollow, muscular Y shaped organ that receives the fertilized ovum, nourishes and houses developing embryos and expels the mature fetus through the birth canal

Forms part of the placenta

Major components: body, uterine horns and cervix

120
Q

What does the thickness and vasculature of the mucous membranes lining the uterus depend on

A

Hormonal changes and pregnancy

121
Q

Describe the cervix

A

Projects caudally into the vagina, it is a smooth muscle sphincter that is tightly closed except at parturition and estrus

122
Q

Explain why it may be difficult to treat uttering infections due to the cervix

A

The cervix has small pouches on either side of the opening which are easily mistaken as the opening to the uterus when using a probe to deposit medications

123
Q

True or false

Mucous may be discharged from the cervix or expelled from the vulva at estrus or prior to parturition

A

True

124
Q

When does mucous production by the cervix increase and why

A

During pregnancy to prevent infections from entering the uterus

125
Q

True or false

the cervix also protects the vagina, making the uterus and the vagina sterile

A

FALSE

the cervix only protects the uterus, the vagina is NOT sterile, the uterus is sterile

126
Q

Describe the vagina

A

Muscular tube that contains mucus glands for lubrication

Extends from the cervix to the vulva

It is the female copulatory organ and part of the birth canal

127
Q

What is the vulva composed of

A

Vestibule: caudal part of the tubular portion of the reproductive tract common to the urinary and reproductive systems

Clitoris: the female counterpart of the penis and is located on the floor of the vestibule

Labia: forms the external boundary of the vulva

128
Q

Where does the urethra enter the reproductive tract

A

At the junction between the vagina and vestibule

129
Q

What is the estrus cycle

A

Defined as the time from the beginning of one heat period to the beginning of the next

130
Q

Describe how the estrus cycle is controlled

A

Controlled by FSH and LH from the anterior pituitary gland

These hormones stimulate production of estrogens from developing follicles and progesterone from the corpus luteum

131
Q

What does estrogens and progesterone do

A

Estrogen: physical and behavioural changes of estrus

Progesterone: prepares for and maintains pregnancy

132
Q

Time of breeding depends on

A

The estrus cycle of the female (males are ready to breed at any time because sperm are produced continuously)

133
Q

When are estrus cycles naturally timed to occur

A

Times to coordinate with seasons of food abundance to give greater reproductive success

Can be stimulated by environmental changes such as increasing length of days or temperature

134
Q

Describe the classification of the estrus cycle according to the number of cycles per year and give an example of each

A

Polyestrus: cycle continuously if not impregnated (pigs and human)

Seasonally polyestrus: seasonal variations in cycling, continuous at some times of the year and absent in others (horses/sheep/cats)

Diestrus: 2 cycles per year, usually spring and fall (dogs)

Monestrus: one cycle per year (fox/ferrets/mink)

135
Q

What are the 5 stages of the estrus cycle

A

Proestrus

Estrus

Metestrus

Diestrus

Anestrus

136
Q

What happens in proestrus

A

Follicular development in response to FSH

increasing estrogen output from follicles cause physical prep for ovulation and breeding, thickening/development of the lining of the oviduct/uterus/vagina and the vagina develops a cornified layer to protect from trauma

137
Q

What occurs at estrus

A

Period of sexual receptivity (peak estrogen levels)

LH release and inhibition of FSH (follicles are mature)

Ovulation normally occurs at the END of estrus

138
Q

Explain what happens during estrus in induced ovulators if they are not bred

How do you treat it

A

(Cats and ferrets)

Will have a prolonged estrus cycle if not physically bred/stimulated

Unwanted behaviours and discharge from vagina during heat will continue up to 2 weeks (ends when the follicle regresses)

Hormonal injections, Q tip stimulation, or spaying (preventative)

139
Q

Why is a prolonged estrus cycle more serious in ferrets

A

High levels of estrogen cause life threatening anemia (non breeding females should be spayed)

140
Q

Describe what happens during metestrus

A

The corpus luteum develops after ovulation in response to LH acting on the empty follicle

Produces progesterone (thicken uterine lining in prep for implantation) and inhibits follicular development

141
Q

Describe what happens during Diestrus

A

Corpus luteum is at max size and effect, if pregnant, the CL will be retained in response to continued LH levels, if not the CL will degenerate

142
Q

What happens if CL degeneration is delayed even if the animal is not pregnant

A

Common in intact bitches

Progesterone levels will continue to prepare the body for pregnancy and can result in a pseudopregnancy (false pregnancy)

Animals develops enlarged mammary glands, may lactate, pelvis may relax, and will see mothering and nest building behaviours

Most will resolve on its own, may need hormonal treatment

143
Q

Describe what happens during anestrus

A

Ovarian inactivity between breeding cycles in all but polyestrus species (these would continue a new cycle)

144
Q

How do females attract males when ready for mating (during heat)

A

Pheromones

145
Q

What is copulation

A

The physical act of breeding

146
Q

Where is semen typically deposited in most species at ejaculation? Where is it deposited in horses and pigs

A

Most: upper portion of the vagina

Pigs/horses: deposited directly in the uterus/at the cervix

147
Q

How do sperm move

A

Active swimming (flagellum)

Propulsive contractions of the uterus and oviducts (stimulated by oxytocin from climax and prostaglandins in semen)

Ciliary action in the oviducts

148
Q

How long does it take for sperm to reach the upper parts of the oviducts

A

1 hour

149
Q

How long can sperm typically survive in humans? What about some other species?

A

Humans: 72 hours

Others: 1 week

150
Q

What is capacitation

A

The changes that sperm undergo to prepare them to fertilize the ovum

Occurs in the oviduct (sperm spend some time in here)

Includes: exposure of enzymes in the acrosome which assist spermatozoa in penetration of the oocyte

151
Q

True or false
Many sperm can penetrate the oocyte

Explain how this works

A

False

Eggs are released when spermatozoa are fully capacitated, and they only allow one sperm to fully penetrate (when this occurs the surface of the oocyte changes to prevent others from penetrating)

Many sperm aid in penetration by use of acrosome enzymes (at the same time, the secondary oocyte changes to a mature ovum)

152
Q

What is the sequence of breeding to fertilization

A

Breeding (before ovulation)

Capacitation

Ovulation

Fertilization

153
Q

What happens after fertilization of the egg

A

Pronuclei of the male and female sex cells (haploid) join to create a diploid fertilized ovum/zygote

Zygote continues to divide and in a few days forms a solid mass of cells now called a morula. (All the while the zygote is moving down the oviduct)

The morula then develops a cavity and is now considered a blastocyst which will implant in the uterus

154
Q

Describe a blastocyst

A

Has an outer layer called the trophoblast (which will develop into the fetal placenta)

And has a inner cell mass that will develop into the embryo

Has a hollow cavity that holds the inner cell mass called the blastocoele

155
Q

Describe how the blastocyst implants Onto the endometrium

A

Creates a small pit by secreting enzymes that dissolve a small piece of the uterine lining, attaches into this pit

156
Q

How many implantation sites do multiparous species have

A

Many sites along the horns and body of the uterus

157
Q

Describe how the blastocyst eventually forms the fetus

A

Trophoblast: forms the fetal placenta

Blastocoele: forms the space in hollow organs

Inner cell mass:

1: ectoderm: the outer cells, form the integumentary, sense organs and nervous system
2: endoderm: cells on the blastocoele side, form the epithelium of the pharynx, lower RESP tract, GIT and bladder/urethra
3: mesoderm: middle cells between the ectoderm and endoderm, will spilt into 2 layers with a cavity between them to form connective tissue, bone, cartilage, muscle, blood/lymph vessels and kidneys

158
Q

When is the embryo considered a fetus

A

When the various organs and organ systems have been formed

159
Q

When does the fetus become a neonate

A

At parturition

160
Q

What are teratogens? Describe what they can be, the effects of them, and what occurs at which stages

A

Teratogen: anything that causes defects in the embryo/fetus

Can be: genetic, infections or environmentally toxic

Effects: death, abortion, malformation, growth retardation

Times:
In early pregnancy: most susceptible, often causes abortions
During organogenesis: (first trimester) causes major developmental problems

161
Q

When is the fetus more resistant to teratogens

A

In later stages when the organs are made

162
Q

What does the development of the placenta allow

A

Increased nutrient and waste exchange from the mother

Acts as the life support system for the fetus

163
Q

Describe the placenta

A

Multilayered, fluid filled membranous sac that forms around the embryo, connected to the embryo via the umbilical cord and connected to the mother via placental attachments

Is the site for nutrient and waste exchange

164
Q

True or false

The fetus’ and mother’s blood mix to encourage nutrient and waste exchange

A

FALSE

Their blood never mixes, runs very close to each other to allow diffusion and exchange of nutrients and waste

165
Q

Describe the layers of the placenta/different sacs

A

Amniotic sac: surround the fetus, fetus floats in the amniotic fluid as protection

Allantoic sac: sac for fluid and gas exchange between the fetus and mother

Chorion: attaches to the uterine lining and linked to the fetus via then umbilical cord

166
Q

The allantochorion is the ___ part of the placenta

A

fetal part

167
Q

What does the umbilical cord contain

A

2 umbilical arteries: Moves waste away from the fetus to the placenta

1 umbilical vein: carries oxygen and nutrients from the placenta to the fetus

Urachus: tube draining fluid from the fetal bladder into the allantoic sac

168
Q

True or false

The fetus forms true urine

A

False

Not true urine, just a byproduct of the developing kidneys

169
Q

What is a diffuse attachment of the placenta to the uterus, give an example of animals with this attachment type

A

Loosely attached sites throughout the placenta, detaches easily and completely

Horses and pigs

170
Q

What is a cotyledonary attachment of the placenta to the uterus, give an example of animals with this attachment type

What is the risk with this type of attachment

A

Many small, button like sites called placentomes

Placental half: cotyledon
Maternal half: caruncle

Very strong attachment formed by interdigitation of the cotyledon and caruncle

Ruminants, cows, sheep, goats

Can have a retained placenta due to incomplete detachment leading to life-threatening Metritis

171
Q

What is a zonary attachment of the placenta to the uterus, give an example of animals with this attachment type

A

Chorion form a belt shaped structure around the middle of the placenta

Usually detaches easily and completely

Dogs and cats

172
Q

What is a discoid attachment of the placenta to the uterus, give an example of animals with this attachment type

A

Disc shaped attachment sites

Humans, primates, rabbits, rodents

173
Q

What is gestation period

A

The time from fertilization to delivery of the fetus

174
Q

Describe the 3 periods/trimester of pregnancy and what occurs in each

A

First trimester: fertilization/implantation/ placenta formation/ early cellular organization (embryo)

Second trimester: fetal development period: differentiation into all different body tissues and organs (basis for different systems) (fetus)

Third trimester: fetal growth period: dramatic growth, preparation for survival after delivery (fetus)

175
Q

What is parturition triggered by

A

Size and weight of the uterus and hormonal changes

176
Q

What are the hormonal changes that occur to stimulate parturition in order

A

1: increased glucocorticoids from the fetus
2: uterus/placenta respond by increasing estrogen and PGF2-alpha causing luteolysis and make uterus sensitive to oxytocin
3: decrease in progesterone due to CL regression -allows uterine contractions and circulating progesterone converts to estrogen
4: oxytocin release from posterior pituitary which stimulate myometrial contracts and the onset of labour

177
Q

What are the 3 stages of parturition

A

1: uterine contractions (no abdominal pushing) presses the fetus against the cervix causing dilation. See changes in behaviour to prepare for birth

Water breaks to mark the END of stage 1 and start of stage 2

2: strong uterine contractions and abdominal pushing increases, delivery of the newborn
3: delivery of the placenta, attachments separate and the placenta is delivered through mild contractions -may be eaten by the mother

178
Q

If the animal is delivering many young, what does this mean with delivery of the fetus’ and placentas

A

Delivery of each will alternate

179
Q

What is dystocia

How do you treat it

A

A problem in the delivery of a fetus due to size or position

Manual repositioning, c-sections, or fetotomy

180
Q

What are some of the several changes that must occur in the fetus at birth

A

Lungs must start breathing air

Urachus must close to prevent urine leakage from umbilicus

Cardiovascular system must start delivering blood to the lungs and not the placenta

181
Q

How does the cardiovascular system start delivering blood to the lungs and not the placenta after birth

A

Foramen ovale: a fetal opening between the right and left atria that shunts blood away from the lungs -closes after birth

Ductus arteriosus: connects the fetal aorta to the pulmonary trunk and shunts blood away from the lungs -shrinks and becomes a ligament after birth (helped by first breath by expanding the lungs and making it easier for blood to flow)

Ductus venosus: in the fetus it takes oxygenated blood from the umbilical vein to the caudal vena cava for circulation in the fetus -constricts and becomes a ligament after birth

182
Q

What happens with time to the uterus after parturition (involution)

A

Involution: the gradual return of the uterus to its non-pregnant size (shrinks)

Sloughing of placental attachments

Myometrial contractions prevent continued bleeding and expel sloughed material and blood.

Discharge can be seen for a week or more after delivery and will gradually get darker

183
Q

What are mammary glands and what do they do. Who are they in?

A

Specialized skin glands that produce colostrum and milk. Found in both males and females but only develops normally in females as secondary sex characteristics.

Grow during pregnancy and attain full size and function during first lactation

After weaning, milk production stops and gland regresses

In older animals the mammary glands regress and the tissue is replaced with connective tissue

Consists of the teat and mammae

184
Q

What are mammae

A

The parenchyma (epithelial tissue) of the mammary gland, resembles lung tissue due to alveoli

Alveoli: milk secreting cells: alveoli connected to alveolar ducts join to form larger ducts which empty into a milk sinus

Milk sinuses: 2: where milk accumulates
Gland sinus: within the mammae
Teat sinus: within the teat

185
Q

What is the teat (papillae)

A

Projected part of the mammary gland that contains the teat sinus. Has a streak canal which is a passage way leading from the teat sinus to the exterior teat opening

186
Q

Describe the streak canal

A

A sphincter of muscle around the streak canal at the end of the teat prevents milk flow unless there is sucking/milking

Ruminants: one streak canal per teat
Equine: 2 streak canals per teat
Cats: several
Dogs: many

187
Q

Why can only large animals be treated with intramammary meds

A

Too many openings that are too small in small animals

188
Q

What are hard milkers? What are easy milkers?

A

Hard milkers: cows that have very tight sphincters (may be from fibrosis of streak canal)

Easy milkers: cows that leak milk have a loose sphincter (may be from frostbite and could be a route of infection)

189
Q

What are the hormones that occur at puberty that stimulate mammary gland development

A

Prolactin: stimulate milk production

Growth hormone: development of udder

Estrogen And Progesterone: indirectly affect mammary gland development because they are produced in response to pregnancy/ovulation

Thyroid hormone and Corticosteroid hormones: could inhibit development if levels are too high

190
Q

What is lactation and what hormones does it require?

A

Process of milk production

Requires: prolactin, growth hormone, and adrenal cortical hormones

191
Q

When can males develop the ability to lactate

A

If Given hormones or with Sertoli cell tumors

192
Q

What is milk composed of

A

Lipids (triglycerides)
Carbohydrates (lactose)
Proteins (caseins, lactalbumin, lactoglobulins)
Water

193
Q

True or false

Animals who nurse frequently have a lower fat content in their milk

A

FALSE

it is higher

194
Q

What is colostrum

A

The first milk after parturition

Contains large amounts of essential nutrients for newborns including; more proteins, lipids and amino acids, essential vitamins, laxatives, and antibodies/immunoglobulins (for immunity)

195
Q

Why is there a laxative in colostrum

A

To help newborn clear the meconium (first feces after birth which is mainly soughed debris)

196
Q

Why should colostrum be given to the newborn within minutes to 24 hours after birth?

A

To ensure passive immunity is passed onto the newborn because the newborns GIT becomes impermeable to immunoglobulin absorption and immunity will not be passed on (at first the GIT can only absorb intact proteins)

197
Q

How is lactation maintained

A

Continues as long as nursing/Milking continues (as long as the gland is emptied and oxytocin release and hormones continue)

198
Q

What is milk let down

A

Milk is stored high up in the mammary gland, needs appropriate stimulus to be “let down” into the teat sinus, stimulation is the physical act of nursing which releases oxytocin from posterior pituitary

Oxytocin causes contraction of the cells around the storage area of the gland and forces milk into the sinuses

Takes a few seconds to minutes

199
Q

When is the term udder used

A

All mammae of ruminants and horses and sometimes sows

200
Q

What does it mean to have supernumerary teats

A

More teats than usual which may or may not be connected to mammary tissue

201
Q

Describe the mammary gland differences in a cow

A

Consists of 4 quarters, each with its own mammary gland

Intermammary groove separates the 2 halves of the udder (cranial and caudal quarters)

Milk vein: caudal superficial epigastric vein that runs along the ventral abdomen that drains the udder (don’t use for venipuncture or you risk damage)

Suspensory ligaments hold up the udder (can weigh >50 kg). These can break and give a dropped udder and splayed teats

202
Q

Describe the canine mammary gland differences

A

Usually have 5 pairs (10 teats) but varies with breed (less in smaller breeds)

Maybe also vary on each side

Divided into throacic (2 pairs), abdominal (2 pairs) and inguinal (1 pair)

203
Q

Describe the mammary gland differences in felines

A

Usually 4 or 5 pairs but can vary

Thoracic, abdominal and sometimes inguinal divisions

204
Q

Describe the mammary gland differences in equine

A

1 pair, one teat on each side of the udder. Each teat has 2 streak canals and 2 teat cisterns (separate milk sinuses so they look like a cow udder internally)

Udder and teat are also covered with numerous sebaceous glands and sweat glands

205
Q

What is mastitis

A

Inflammation of the mammary gland, usually associated with infection, can start in one teat and spread to others

Treatment: stripping the teats/sinuses completely, infusion of medications through the streak canals (have to strip out as well)

Signs: swelling, warm teat, redness, reduced milk production, painful on palpation

Cows: each quarter is separate so it can be in one or all four quarters

206
Q

Describe tumors if the mammary glands, who is most affected and how are they treated?

A

Canines most frequently affected

Lumpectomy: removal of the tumor only
Mastectomy: whole gland removal
Ovariohysterectomy: to remove hormones on which tumors cells may depend on

207
Q

Describe the variations of the female reproductive system in the canine

A

Ovaries: almond shaped, lie caudal to the kidneys, suspensory ligament of the ovary attaches the ovary to the last rib

Uterus: very long horns (adaptation for litter bearing), simple cervix with a cranioventral vaginal recess (fornix)

Vagina: vestibular bulbs (erectile venous plexus in vestibular walls, partly responsible for the tie during copulation) , os clitoris (small bone in some bitches)

Vaginal process: e vagina took of the parietal and visceral peritoneum through the inguinal canal that contains the round ligament

208
Q

What are vaginal smears used for in small animals

A

To Evaluate the stage of estrus cycle for breeding purposes

209
Q

Describe the variations of the female reproductive system in equines

A

Ovaries: bean shaped with well developed hilus, lie caudal to kidneys

Uterus: relatively short horns equivalent to length of uterine body

Cervix: simple cervix bulging into vagina with vaginal recess (fornix)

210
Q

Describe the variations of the female reproductive system in bovine

A

Ovaries: almond shaped, lie at the pelvic inlet

Uterus: long horns, short bodies, ends of the horns are coiled up and are bound together by the intercornual ligament (gives false impression of being long), has mushroom like projections (caruncles)

long cervix with transverse folds (occlude canal with mucus secretions making it difficult to inject anything into uterus)

Vagina: distinct craniodorsal vaginal recess around the cervix (fornix)

Broad ligament: attached along the pelvic inlet instead of the dorsolateral body wall

211
Q

What is dystocia and how is it treated

A

Difficulty giving birth due to size or position

Treatment: manual manipulation, traction, lubrication, fetotomy

212
Q

What are the ovaries susceptible to

A

Several disease and abnormalities; hypoplasia, cystic follicles, neoplasia or can be congenitally absent or can descend through inguinal canal

213
Q

Describe tubal ligation

A

Performed in people but not in animals

Sterilizes but does not stop estrus and unwanted behaviours

214
Q

Describe ovariectomy/oophorectomy

A

Removal of the ovaries alone (newer procedure used in animals)

No increased risk of Pyometra

Similar in pain and time to ovariohysterectomy

215
Q

Describe an ovariohysterectomy

Describe the procedure

A

Removal of the ovaries and uterus

Renders animal sterile and stops estrus

Most common elective surgery in carnivores

Procedure:
Suspensory ligament of the ovary is cut
Ligatures placed in ovarian vessels and broad ligament
Round ligament is broken down by blunt dissection (tearing) for faster clotting
The uterine stump is clamped, ligated and severed including the vessels

216
Q

What does pregnancy or estrus do to surgery/spaying

A

Complicates the procedure by increasing blood supply

217
Q

What is pyometra

A

Common in older unspayed dogs

Infection of the uterus (requires right hormonal conditions)

Prolonged luteal phase in dogs due to CL persisting (8-10 weeks) allows the cervix to remain open allowing bacteria to enter
After, progesterone thickens walls and increases secretions and the cervix closes, creating a perfect culture medium for bacteria

Treatment: medical treatment, ovariohysterectomy

Can use PGF2-alpha to save uterus (cause luteolysis to relax cervix and stimulate contractions)

218
Q

What is endometritis

A

Infection or inflammation of the lining of the uterus

Common in horses and cattle

219
Q

What is uterine adenocarcinoma

A

Malignant tumour of the uterus

Common in 3yo+ unspayed rabbits

220
Q

Who is most susceptible to uterine prolapses

A

Postpartum cows and usually have milk fever

221
Q

Who is most susceptible to vaginal prolapse

A

Postpartum cows due to prepartum straining

222
Q

What is pneumovagina (wind suckers)

A

Most common in equine (conformational defect)

Sunken vagina, lips don’t close properly and they get contaminated when feces falls in or urine pools in the vestibule (creates a reproduction problem)

Anatomy And Physiology (8 decks)

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