Embryology Flashcards
Lesion
any abnormality in a tissue/organ.
Inflammation
the reaction of living tissue to local injury
Cardinal Signs of Inflammation
heat, redness, swelling, pain, loss of function
Histology
what normal tissue looks like under a microscope
Histopathology
what abnormal tissues look like under a microscope
Pathology
something abnormal
Trophoblast
epithelial layer that arises from cells on the outside
Inner Cell Mass
cells on the inside
Gastrulation
the stage where the three germ layers are formed
What are the three germ layers?
ectoderm, mesoderm, endoderm
Ectoderm
skin and associated glands; gives rise to epithelial tissues
Mesoderm
supportive tissues, circulatory system, urogenital, mesenchymal tissues
Endoderm
lining of GI system, respiratory system, and urinary bladder. Pancreas and gives rise to epithelial tissues
Tumor
mass/ swelling/ nodule
Types of Tumor
cyst, inflammation, hyperplasia, neoplasia
Adenoma
Benign tumor of epithelial cells of endodermal or ectodermal origin
Fibroma
Benign tumor of fibroblasts- cells in connective tissue- arises from mesenchymal cells
Osteoma
benign tumor arising from the mesenchymal cells in the bone
Carcinoma
malignant tumor arising from endodermal or ectodermal origin
Sarcoma
Malignant tumor arising from mesenchymal cells
Notochord
extends along midline for the length of the embryo. It moves caudally to drag the notochord the full length of the embryo. It eventually becomes the intervertebral discs. Of Mesodermal origin
Neuroectoderm
originates from the ectoderm directly above the notochord. Invaginates to form the neural groove which then pinches off to form the neural tube.
Neural Tube
becomes brain and spinal cord. Lumen of the tube becomes central canal within the brain and spinal cord filled with cerebrospinal fluid
Spina Bifida
failure to complete closure of the neural tube
Neural Crest Cells
originate from the neural tube and become melanocytes, Schwann cells, adrenal medulla cells, and PNS cells
Lethal White Foal Syndrome
from breeding two frame overo spotted parents. White because of incomplete migration of melanocytes. They don’t have nerve cells in their colons. their colons are small and don’t move much
Melanocytoma
benign tumor of melanocytes
Malignant Melanoma
malignant tumor of melanocytes
Pheochromocytoma
benign tumor of adrenal medulla cells
Malignant pheochromocytoma
malignant tumor of adrenal medulla cells
Functions of Placenta
- supply or storage of nutrient
- respiratory exchange
- excretion of wastes
- mechanical protection of the embryo
- transfer of maternal antibodies
- hormone production
Extra-Embryonic Membranes
amnion, chorion, yolk sac, allantois
Amnion
directly surrounds the embryo (Mechanical protection) ; lined by ectoderm and is continuous with the skin of the baby
Chorion
outermost membrane that interdigitates with the lining of the uterus for exchange of nutrients and waste. Surrounds the baby, amnion, and yolk sac
Yolk Sac
cranial outpouching of the fetal gut, very important in birds and reptiles. Lined by endoderm
Allantois
caudal outpouching of the fetal gut. Lined by endoderm. Starts small and grows to surround the entire baby and fill the uterus. Mostly fused with chorion to form chorioallantois so urine etc. gets transferred back to mom and she excretes it. Continuous with bladder
Urachus
segment connecting the allantois and bladder
Patent Urachus
most common urinary bladder malformation. When urachus doesn’t pinch off and close at birth. Dribble urine from umbilicus. Prone to infection
Umbilical Hernia
if the abdominal wall doesn’t close. The intestines can get the stuck through the hernia in the abdominal wall and lose their blood supply. This can result in a breakdown of the barrier function of the intestines s all the intestinal bacterial can enter the bloodstream
Atresia Ani
failure of the membrane that separates the rectum from the overlying ectoderm to breakdown (no anus)
Parenchyma
the key fundamental elements of an organ; the cells that make an organ function
Stroma
the supportive framework
Mesonephric Duct
remnant of a primitive kidney. Induces the mesonephric tubules and mesonephros (gonads, tubular genitalia, etc.)
What direction does the urinary system develop in?
caudal to cranial
What direction does the reproductive system develop in?
cranial to caudal
Metanephros
permanent kidney. Develops from mesoderm and is induced by the ureteric buds arising from the bladder
Formation of the Cardiovascular System
mesoderm aggregates into blood islands. The cells on the periphery of these aggregates flatten out to become squamous cells (endothelium) that line blood vessels. The cells in the center become blood precursors
Ductus Venosus
allows fetal blood to bypass the liver and enter the caudal vena cava. After birth this closes and becomes the ligamentum venosum
Foramen Ovale
blood from the vena cava enters the right atrium and bypasses the lungs by going directly to the left atrium. patent foramen ovale is not a big deal
Ductus Arteriosus
some blood from the pulmonary artery goes through it so that it goes into the aorta instead of the lungs. patent ductus arteriosus is a big deal for the animal
What does the ductus arteriosus become?
ligamentum ateriosum
Dermatome
part of the mesoderm adjacent to the neurotube that becomes dermis
Myotome
portion of the mesoderm adjacent to the neurotube that becomes skeletal muscle
Sclerotome
portion of mesoderm adjacent to the neurotube that becomes cartilage and bone
Examples of a Lesion
hemorrhage, hyperplasia, inflammation, cysts, necrosis
