Lecture Terms Flashcards
axial skeleton
vertebral column, skull, ribs, sternum
appendicular skeleton
long limbs, pelvic and pectoral girdle
flexion angle
depends on functionality - flexing a muscle will happen if the flexor angle is DECREASED
cranial/caudal above the hock or manus
palmar/plantar/dorsal beneath it
Five recognized radiodensities
From radiolucent to radiopaque:
Air, Fat/Oil, Water/Soft Tissue, Bone, and Metal
Orthogonal angle
A perpendicular angle, necessary to get 3d information from two 2d images
Why are shoulder and scapula fx and luxations relatively uncommon?
Scapula is held close to the body and has a great deal of muscle padding. The shoulder has a very large articular surface - it is hard for it to get displaced.
Why are humeral and rad/ulna fx common?
Far from the body and more exposed
Meant to bear weight cranially/caudally not orthogonally.
Is luxation of the elbow usually medial or lateral?
Lateral. The capitulum and the lateral epicondyle of the humerus are both smaller than their medial counterparts.
How should luxation of the elbow be reset?
With the elbow flexed. The olecranon will be in the way otherwise.
luteinizing hormone (LH)
Hormone that surges 24 hours prior to ovulation. Causes the maturation the follicle/oocyte.
What is the progression of the maturation of the oocyte in the ovary?
Primordial follicle Secondary follicle Mature follicle Ovulation Corpora lutea
What are the major trends of progesterone and estrogen during proestrus?
estrogen decreases hyperbolically
progesterone increases hyperbolically
How long after breeding can the sperm fertilize the egg?
Species dependent.
Most: 4-6 days
Horses/Dogs: 7-10 days
When does the oocyte’s first mitotic division takes place and what is formed?
After sperm are in place but before fertilization. Creates the female pronucleus and the two polar bodies.
What produces progesterone?
corpora lutea
Where is the sperm deposited.
Species dependent.
Vagina, cervex, or uterine body
Where does fertilization of the egg occur?
In the oviduct
aka the uterine tube
What facilitates the movement of sperm to the oviduct?
Increase in mucus production of the uterus during ovulation.
What are the three key reactions of fertilization?
Capacitation, Acrosome, and Cortical reactions.
Capacitation
Sperm
Shedding of the glycoprotein coat while in the uterine tube. Exposes reactors on the head of the sperm.
Acrosome
Sperm
Proteolytic enzymes are released from the acrosomal vesicle which starts digesting the outer portion of the zone pellucida so that the sperm can enter and start the cell division process.
Cortical
Oocyte
Prevents polyspermy. After one sperm breaks in there is a large increase in intercellular calcium. This changes cell surface ligands and creates a zone-block against other sperm.
When do the male and female pronuclei form?
Female - first meiotic division just before fertilization.
Male - Directly after fertilization.
When does the fertilized oocyte become a zygote?
Once female and male pronuclei form they fuse and mitotically divide. After this division the body is considered a zygote.
What is the role of the polar bodies?
Created during first meiotic division. Help with the first mitotic division.
What is the general rule of developmental potential?
As differentiation of the cells increase, the developmental potential of those cells decreases.
VERY GENERAL (5) important functions of fertilization
- Restore the diploid karyotype.
- Determination of chromosomal sex
- initiation of cleavage
- activation of the embryonic genome
- activation of the epigenetic genome
The preformation theory
Every sperm contains a very tiny model of the animal that it will become.
The epigenesis theory
Based on actual fetal observations starting with Aristotle.
A landscape with factors pulling it different ways to create hills and valleys. Each cell is a ball that rolls down these hills to a different but mostly determined fate.
CRL
Crown-Rump Length
Used to judge the age of a domestic embryo, designed using years of empirical evidence.
Embryonic charts
Predict the stage of fetal development using age or CRL.
Hox genes
AKA Homeobox genes
Regulatory genes that help pattern the embryo with limb patterns, resp, GI, and nervous systems.
Where the genes are locate helps with this patterning.
First found in Drosophila.
ARTs
Assisted Reproductive Technologies
- artificial insemination
- oocyte transfer
- nuclear (somatic) cell transfer - CLONING
Cloning process
AKA somatic or nuclear cell transfer
Enucleate an existing oocyte. Take adult somatic cell (mammary epithelial is most common) and fuse it with the oocyte to create a reconstructed oocyte.
Why does cloning only succeed 5-10% of the time?
Creation of the reconstructed oocyte skips all of the fertilization control steps. Cannot tell if it is viable until it fails.
What are some possible future applications of cloning?
Pet cloning
Endangered species cloning
Research animal cloning
Organogenesis
Development of organs, limbs, and organic body material
Teratogenesis
The development of congenital defects within an embryo.
Gametes
Haploid genetic material carriers - the sperm and the egg.
Zygote
The embryo in a 2-cell state. Diploid with both sets of genetic material after one mitotic division.
Morula
“Mulberry” - a group of large divided cells. Relatively random. Last totipotent stage.
Blastocyst
Cells have grown much smaller and a fluid filled cavity has grown in the center. Pleuripotent cells.
Folded tri-laminar embryo
3 layered embryo proper, after gastrulation. Multipoint cells.
Fetus
After approximately 35 days of growth. Unipotent cells.
Totipotent
Cells can be ANYTHING. This only is for the first few cell divisions.
Pluripotent
All the cell types that make up the embryo and the embryonic tissues (stem cells)
Multipotent
Mesoderm, Ectoderm, or Endoderm
Unipotent
Can become only one cell type
Types of cells in the blastocyst
Zona pellucida cells
Inner cell mass
trophoblasts
Inner cell mass of the blastocyst
Cells that will form the embryo proper and the embryonic tissues.
Trophoblasts
Will communicate with maternal endometrium and help form embryonic tissues
What tells the cells what to become, where to go, and how to develop?
Differentiation: what
Patterning: where
morphogenesis: how
Zona Pellucida
Layer of compact cells. Common from the oocyte until the blastocyst
Function of the fluid filled cavity of the blastocyst
Will “hatch” out of the blastocyst to interact with the endometrium and allow trophoblasts to interact as well.