Introduction to Theriogenology Flashcards
1
Q
What are oviparous animals?
A
- Egg laying
- Ovum surrounded by large amount of yolk
- +/- internal fertilization
- Birds, fishes, amphibians
2
Q
What are Ovoviparous aniimals?
A
- Egg (non-placental) incubation with birth of live young
- Have egg with protective shell
- Internal fertilization and internal hatching
- Most reptiles
3
Q
What are viviparous animals?
A
- Placental gestation with birth of live young
- Mammals - suckle young
4
Q
What are Monotremes?
A
Mammals that lay eggs and suckle young (platypus)
5
Q
What is the location and function of Ovaries?
A
- Caudal to the kidneys - suspended from the body wall by part of the broad ligament (“suspensory ligament”
- Secrete gametes via tubular genitalia (uterine tube + uterus)
- Produce hormones (estradiol and progesterone)
6
Q
What are the important structures of the Ovary? function?
A
- Peripheral parenchyma (cortex) - contains various stages of follicular and luteal gland development (most species)
- Central Vascular zone (medulla) - contains connective tissue rich in blood vessels (most species)
-
Follicles - enclose oocyte, become fluid-filled, estradiol (and others) become concentrated in follicular fluid.
- palpable in bovine at > 6-10mm diameter
- Corpora lutea - after ovulation (or lutenization w/o ovulation), the cells of the follicle become corpora luteal cells
7
Q
What are the important structures of the Ovary? function?
A
- Peripheral parenchyma (cortex) - contains various stages of follicular and luteal gland development (most species)
- Central Vascular zone (medulla) - contains connective tissue rich in blood vessels (most species)
-
Follicles - enclose oocyte, become fluid-filled, estradiol (and others) become concentrated in follicular fluid.
- palpable in bovine at > 6-10mm diameter
- Corpora lutea - after ovulation (or lutenization w/o ovulation), the cells of the follicle become corpora luteal cells
8
Q
Where is the bovine Ovary located? palpable structures?
A
- Readily palpated
- Suspended from the broad ligament cranial or cranial-lateral to the tip of the uterine horns
- Palpable structures:
- Tertiary follicles (possess fluid-filled antrum)
- Corpora Lutea (CL)
- Corpora haemoragicum (not always able to ID)
- Corporal albicans (regressing CLs)
9
Q
What does the Equine Ovary look like? palpable structures?
A
- Bean shaped
- Not as freely moveable as bovine
- Ventral border is concave (ovulation fossa)
- Peripheral area is vascular connective tissue and central parenchyma has follicular and luteal gland tissue (inside out)
- Palpable structures:
- Follicles located in the ovulation fossa
- Corpora lutea are NOT palpable
10
Q
What are the parts of the Uterine tubes? functions?
A
- Fimbria - cilia sweep the ovum from the ovary at ovulation into the infundibulum
-
Infundibulum -⅓ portion of the uterine tube nearest the ovary
- funnel-like, catches the ovum at ovulation
-
Ampulla - middle third of the uterine tube
- sight of fertilization
-
Isthmus - Portion of uterine tube closest to uterus
- Uterotubal junction (UTJ) in the equine acts as a mechanical barrier to the passage of the early (
11
Q
what is the structure and function of the Uterine Horns?
A
- Formed from the paired Mullerian Ducts
- Lined with a vascular and glandular mucosa and contain smooth muscle
- Endocrine (hormone producing) organ
12
Q
how is the Uterus formed?
A
- Stars as 2 long tubes (Mullerian ducts)
- Degree of fusion of the ducts varies by species
13
Q
What is a Unilateral tract?
A
- Only the left Mullerian duct forms into a functional oviduct/uterus
- Birds
14
Q
What is a Marsupial uterine tract?
A
- Mullerian ducts fuse very distally (near vulva) therfore, have 2 vaginas and 2 cervix
- Opossum, Kangaroo, Koala, etc
- Male opossum have forked penis - so do sugar gliders
15
Q
What is a Duplex uterine tract?
A
- Mullerian ducts fuse very distally
- 1 vagina and 1 or 2 cervix
- No migration of embryos between horns
- Most Rodents
16
Q
What is a Bicornuate uterine tract?
A
- 2 long horns
- Mullerian ducts fuse cranial to cervix (short uterine body)
- Easy migration of embryos between horns
- Porcine, Canine
17
Q
What is a Bipartate uterine tract
A
- Two horns with distinct septum
- Mullerian ducts fuse cranial to cervix - short uterine body
- Seldom have migration of embryos between horns
- Bovine, Ovine
18
Q
What is a Modified Bipartate Uterine Tract?
A
- 2 horns
- long uterine body - as long as horns
- Equine
19
Q
What is a simplex uterine tract
A
- Mullerian ducts completely fused - no horns (only uterine body)
*
20
Q
What are some common uterine abnormalities?
A
- Cows - 2 cervixes
- Humans - Bicornuate uterus (instead of simplex)
21
Q
What is the cervix and its function?
A
- Connective tissue and muscle forms tube-like sphincter
- Almost always “closed” - acts as a barrier to protect uterus
22
Q
What is special about the equine cervix?
A
- No cartilage
- Changes tone during estrus cycle
- based on concentrations of progesterone and estradiol
23
Q
What is the vagina and its function?
A
- Caudal to uterus/cervix - located in the pelvic canal
- Where sperm is deposited in many species
- Very long in the canine
24
Q
How many layers are in the placenta? what are they?
A
- up to 6 layers of tissue
- Maternal tissues:
- Blood vessel endothelium
- connective tissues (syndesmo layer)
- Epithelium of endometrium
- Fetal tissues:
- Chorion
- Connective tissue
- Blood vessel endothelium
- Maternal tissues:
25
What is epithelial Chorial placentas? which animals have this type of placenta?
* Maternal epithelium of the endometrium is in contact with the fetal chorion
* (no erosion of the epithelium)
* All 6 layers of tissue are intact throughout pregnancy
* Sow, Mare
* Cattle, sheep
* modified - AKA Syndesmo-chorial
* not as much intact epithelium as the sow and are
26
What is a Endothelial-chorial placenta? which animals have these?
* Maternal blood vessel endothelium is in contact with fetal chorion
* i.e. uterine epithelium is eroded over sites of contact with the chorion)
* 2 layers of tissue (epithelium and connective tissue of endometrium) have been removed at fetal-maternal contact sites
* Dogs, cats, others
27
What is a Hemochorial placenta? What animals have these?
* Maternal blood is in direct contact with the fetal chorion
* 3 layers of tissue (epithelium and connective tissue of the endometrium as well as the blood vessel endothelium ) have been _removed_ at fetal-maternal contact sites
* Mice, rates, primates, guinea pig
28
What type of chorionic villous pattern do pigs have?
diffuse
29
What chorionic villous pattern do equines have?
diffuse and micro-cotyledonary
30
What is a Cotyledonary Placenta? Which animals have these?
* Have a Placentome
* Caruncle (maternal)
* Cotyledon (fetal)
* Cow, Sheep
31
What is a Zonary placenta? which animals have these?
* a
* Dogs, Cats
32
What is a discoid placenta? which animals have this type of placenta?
* a
* Primates, rodents
33
What are the differences in male reproductive tracts between a Bull, Stallion, Boar, Dog, Tom?
34
What is the purpose of the penis?
* Copulatory organ
* Deposits semen (sperm cells + accessory gland fluid) into vagina or cervix/uterus (species dependent)
35
What are the different types of penis?
* Fibroelastic penis - minimal erectile tissue
* ruminants
* Vascular penis - a lot of tissue that responsds to sexual stimulus by pooling blood w/in spongy spaces leading to erection
* Equine
* Boney penis - Os penis - only achieve erection after intromission
* Canine, Feline
36
What are the parts of the male reproductive tract? what are their functions?
* Testicles and secondary sex organs
* epididymis, vas deferens, and penis - transport sperm from the testicle to the female reproductive tract
* Ampulla is a dilation of the vas deferens that pools sperm during ejaculation
* 3 accessory sex glands - seminal vesicles, prostate, bulbourethral gland provide fluid for semen
* Testicles - **produce spermatozoa & testosterone**
37
Where are the testes located? Why?
* In many mammal - outside of the body cavity in the scrotum
* essential for normal sperm formation which occurs at a temperature below normal body temp
* In birds - intra-abdominal and held at body temperature
* sperm survives longer in female tract
* Chickens only need to make once a week (turkeys every 2)
38
What is the pampiniform plexus?
* Found in the neck of the scrotum
* complex venous network that surrounds the testicular artery and functions as a countercurrent heat exchanger to reduce testicular temperature
* important for thermoregulation
39
How does the scrotum protect the testicles from extreme temperatures?
* contains a temperature sensitive layer of muscle (tunic dartos) under the skin of the scrotum
* relaxes when hot
* contracts when cold
40
How does the Cremaster muscle help protect the testicles against temperature extremes?
* when relaxed - testicles are ‘dropped’ increasing the relative length of the scrotum - move the testicles away from body heat
* In cold weather - Cremaster contracts and the testicles are pulled closer the the warm body
41
What is the structure of the Seminiferous tubules?
* Many hundreds of individual seminiferous tubules in the testicle
* they unite with one another until approximately a dozen tubules pass out the testicle into the head of the epididymis.
* Made up of Sertoli cells and layers of germ cells
