Embryology- General and Cardio Flashcards
Ectoderm Derivatives
Can be divided into
- Surface ectoderm (MOO DEAD PEEL)
- Neural ectoderm (COARNEE)
- Neural crest cells (PASS DR PAM the two-Faced PESO)
Neural crest cell derivatives
Pia mater, Peripheral nervous system neurons
Arachnoid mater
Schwann cells
Sympathetic chain (autonomic postganglionic neurons)
Dorsal Root ganglia
Pigment cells (melanocytes)
Adrenal Medulla chromaffin cells (vs. adrenal cortex, which is derived from mesoderm)
Facial and skull bones
Facial cartilage
Parafollicular C cells Endocardial cushions of the heart Spiral septum (aorticopulmonary septum) Odontoblasts (creates dentin)
Endoderm Derivatives
HIT EMU, BURPS
Hepatocytes
Inferior 2/3 of vagina
Thymus and Thyroid
Entire gastrointestinal lumen (oral cavity through superior pectinate line)
Middle ear cavity and eustachian canal
Urethra (except distal male urethra derived from ectoderm), Urinary bladder
Bulbourethral glands (Cowper's) Urethral glands (Littre's) Respiratory tract Parathyroid and Pancreas Sublingual and submandibular glands
Lateral plate mesoderm derivatives
- Parietal serous lining of body cavities (somatic portion of lateral plate mesoderm aka Somatopleure)
- Cardiovascular system (splanchnic portion of lateral plate mesoderm aka Splanchnopleure)
- Limb buds development
- Visceral serosal linings of organs
- Dorsal mesentery (ultimately the spleen)
Notochord derivatives
Nucleus pulposus of the intervertebral discs
Paraxial mesoderm
Derivatives
Sclerotome, forming the cartilage and bone of the axial skeleton (including the vertebral column, sternum, and ribs)
Myotome, forming the skeletal muscles
Dermatome, forming the dermis of the dorsal skin
Intermediate mesoderm
Derivatives
Kidneys Adrenal cortices Superior ureters Superior one third of the vagina Uterus and cervix Testes Ovaries
Hypaxial Mesoderm
Derivatives
Differentiates into Ribs, Intercostal muscles, Oblique muscles (thoracoabdominal walls)
Limbs
(part of paraxial mesoderm)
Surface Ectoderm
Derivatives
MOO DEAD PEEL
Mammary Glands
Oral Cavity
Olfactory Epithelium
Distal anal canal below the pectinate line
Enamel (ameloblasts are derived from surface ectoderm)
Adenohypophysis (via Rathke pouch)
Distal male urethra
Parotid salivary glands
Epidermis and accessory structures (e.g. hair, nails, sweat glands, sebaceous glands)
Ear; both the internal and external ear (not middle ear)
Lens of the eye
Neural Ectoderm
Derivatives
COARNEE
CNS neurons within the brain and spinal cord
Oligodendrocytes
Astrocytes
Retina, iris, and optic nerve
Neurohypophysis (aka the posterior pituitary)
Epithalamus (aka the pineal gland)
Ependymal cells
When does Meiosis arrest in females, and when does it restart?
When does it end?
- Meiosis arrests in Prophase I at 5 months in utero
- Meiosis restarts during ovulation
- Fertilization completes meiosis
What is an ectopic pregnancy?
- A fertilized ovum fails to enter the oviduct from the ovary
- Instead lands on (any) abdominal surface
Fertilized ovum can also stay in ovary instead of going to uterus
What secretes hormones for ovum to promote/maintain pregnancy?
- Corpus luteum- secretes PROGESTERONE until ~10 days in
- If egg is not fertilized by then, it stops and degenerates into Corpus albicans (fibrous scar tissue) - Trophoblasts- secrete chemical messages to avoid autoimmune rejection by mother
- Synctiotrophoblasts secrete hCG ~9 days post-fertilization
- Signal to Corpus luteum to keep secreting PROGESTERONE (now called corpus luteum graviditatis)
NOTE: Secretion of prostaglandins at this point will result in abortion of fetus - Eventually, in humans, placenta will take over PROGESTERONE production
What are the parts of the bilaminar disc embryo?
- Amnion (above epiblast cells)
- Epiblast layer (top)
- Hypoblast layer (bottom)
- Yolk sac (underneath hypoblast)
- Everything is enclosed by chorionic cavity (derived from original trophoblasts)
- Smooth chorion
- Villous chorion (forms placenta)
[Note, Villi consist of: cytotrophoblasts (surround epiblasts/hypoblasts), then surrounding that are Syncytiotrophoblasts]
What germ layer forms the vasculature?
Lateral plate mesoderm
What germ layer forms the original kidneys of the body?
Intermediate mesoderm
What are the four primary body cavity membranes?
- Pleural membranes (one for each lung)
- Pericardial membrane (surrounds heart)
- Peritoneal membrane (surrounds stomach/intestine/liver, other abdominal cavity organs)
What forms the periosteal membranes
Lateral plate mesoderm
What germ layer makes the smooth muscles?
Lateral plate mesoderm
What do the sclerotomes eventually become?
Vertebrae (they resegment, then differentiate)
What does the dermatome become?
Dermis of the skin, overlying muscles
What does the myotome become?
Skeletal Muscles
What does the hypaxial mesoderm form?
- Ribs
- intercostal muscles
- oblique muscles of abdominal wall
- limbs (upper limb externally rotates, lower limb medially rotates)
Where are the four major celomic cavities?
Celom= space b/w parietal and visceral layers
- One for each lung
- One for the heart
- One for entire abdomen