Lecture 3 8/28/23 Flashcards
How are metastasizing cancers named?
they keep the name of the original cancer
What is a teratoma?
-a tumor with elements of all three germ layers
-often arise in gonads due to increased levels of undifferentiated cells
What is the notochord?
-tube of mesoderm
-becomes part of vertebral column
-runs full length of body
What is the neural tube?
-ectoderm over the notochord
-becomes neuroectoderm
-pinches off to form neural tube, which becomes brain and spinal cord
What is the lumen?
the space inside a tubular structure (such as the neural tube)
What does the lumen of the neural tube contain?
cerebrospinal fluid
What is spina bifida?
failure of the neural tube to fully close?
What are the types of spina bifida?
-occult: skin still closes despite neural tube not properly closing
-classic: skin over the neural tube does not fully close
What are neural crest cells?
-cells that emerge during the pinching off of the neural tube
-not classified into the germ layers
What do neural crest cells become?
-cells of the nervous system
-melanocytes
-adrenal medullary cells
Why is it bad if neural crest cells fail to migrate?
-regions of the body can be lacking the cells that neural crest cells differentiate into
-can cause problems in development that can be fatal
How do we name tumors that arise from neural crest cells, since they do not fit into any of the germ layers?
-benign tumors: name of cell + -cytoma
-malignant tumors: malignant + name of cell + -oma
What does it mean for something to be multi-focal?
there are multiple spots (typically tumors)
What are the 4 extra-embryonic membranes of the placenta?
-amnion
-yolk sac
-allantois
-chorion
What is the chorioallantoic?
a fusion of the allantois and chorion membranes
What is the purpose of the amnion?
to encircle the amniotic fluid and cushion the baby
What is the role of the allantois?
surrounds the amniotic sac
What is the connection between the allantoic cavity and the embryo’s digestive and secretory systems?
the allantoic cavity, digestive system, and secretory (waste) systems are all connected in utero
What is the chorioallantoic placenta?
where the allantois and chorion fuse within the placenta
What is the urorectal septum?
endodermal tissue that grows between the urethra and rectum to separate them
What membrane is the gut continuous with?
yolk sac
What membrane is the urachus continuous with?
allantois
What is a cloaca?
a common passageway for urine, feces, and reproduction
What are the characteristics of the umbilicus?
-contains outpouchings of the GI tract and urinary tract
-the tracts retract prior to birth and umbilicus pinches off
What is the urachus?
a brach off the bladder that leads into the umbilicus
What happens when a patient has a patent urachus?
-urachus remains open when it should not
-animal now has an extra opening into the bladder which is prone to infection
When does an umbilical hernia occur?
when the GI tract and urachus do not retract through the umbilicus prior to birth
What is the anal membrane?
-ectoderm covering the rectum during development
-breaks down to create the anus
What is atresia ani?
when the anal membrane fails to break down, resulting in an animal without an anus
What tissue gives rise to the liver and pancreas?
endoderm
What are parenchyma?
-functional elements of solid organs
-cells that provide the organ function
What are stroma?
-supportive framework of solid organs
-connective tissue and blood vessels
What tissue gives rise to the respiratory system?
endoderm
What tissues give rise to the urinary system?
endoderm and mesoderm
How does the urinary system give rise to the kidneys?
-ureteric buds arise from bladder
-buds interact with mesoderm to form ureters and kidneys
What tissues give rise to the reproductive system?
endoderm and mesoderm
How do the kidneys give rise to the reproductive system?
-three primitive kidneys form
-one creates a mesonephric duct
-this duct induces mesonephric tubules and mesonephros
-gives rise to gonads, tubular genitalia, etc.
What is the role of the chorion?
interdigitates with uterus
