Week 2 Flashcards
What does the mesodermal layer of gut form from?
Splanchnic/visceral mesoderm
What mesodermal layer line the body cavity?
Somatic/parietal mesoderm
What is the septum transversum and its function? What becomes of it? (2)
- Mesodermal layer that splits the coelom (intraembryonic cavity) into thoracic and abdominal cavity.
- Develops into part of diaphragm.
What is the allantois and its function? What becomes of it? (3)
- Endodermal layer surrounded by blood vessels (becomes umbilical arteries and veins)
- Helps with gas exchange and excretion
- Becomes urachus (connects fetal bladder to yolk sac)
Describe the process of stomach development. (3)
- More growth at dorsal side (less at ventral side) resulting in larger curvature of stomach.
- Rotates 90 degrees result in dorsal end going to left and ventral end going to right.
- Rotation around dorsal-ventral axis bends duodenum into c-shape.
Describe the process of lung development and which germ layer gives rise to it.
- Endodermal cells thickens, cells proliferate to form buds which continues to lengthens and then bifurcation occurs.
- Bifurcation is when the buds form branches.
What does the foregut consists of and what are its derivatives? (4) (6)
- Pharynx
- Oesophagus
- Stomach
- Proximal duodenum
- Derivatives (thyroid, parathyroid, lungs, liver, gall bladder, pancreas)
What does the midgut consists of?
- Distal duodenum, half of colon
What does the hindgut consists of and what is its derivative? (2)
- Other half of colon to anus
- Urinary bladder
Which cells are head structures derived from?
- Neural crest cells (ectodermal)
What are pharyngeal arches and what cells is it made of? (3)
- Outer coverings of ectoderm.
- Mesenchymal core derived from mesoderm and neural crest cells
- Each pharyngeal arch contains central cartilaginous skeletal element, striated muscle rudiment, arch specific cranial nerve, aortic arch artery.
What is the pharyngeal cleft covered by?
- Ectoderm
What is the pharyngeal pouch covered by?
- Endoderm
What cells are central cartilaginous skeletal element derived from?
Neural crest cells
What cells are striated muscle rudiment derived from?
Head mesoderm
What cells are aortic arch artery derived from?
Endothelial cells derived from mesoderm
What are primordial germ cells and how are they separated? (4)
- Precursors of sperm and egg, separated early in development (blastocyst) by inductive signalling from surrounding cells.
- Specified at base of allantois (not within gonads)
- Moves towards intermediate mesoderm where gonads are formed in the embryo.
- Migration along hindgut, through dorsal mesentery, split up to coalesce with left and right genital ridges and then stop migrating.
What are the major parts of the brain?
- Cerebrum
- Diencephalon
- Brainstem
- Cerebellum
What does the diencephalon consist of?
- Hypothalamus
- Thalamus
- Pineal gland (part of epithalamus)
What does the brainstem consist of?
- Midbrain
- Pons (bridge)
- Medulla oblongata
What constitutes the meninges?
- Dura mater, arachnoid membrane, pia mater
Where is the subarachnoid space and what is it filled with?
- Between the arachnoid membrane and the pia mater.
- Filled with CSF
What are the 3 dura folds?
- Falx cerebri
- Tentorium cerebelli
- Falx cerebelli
What is CSF and what is it produced by?
- Cerebral spinal fluid is filtrate from blood produced by choroid plexus (vascular tissue/capillary) in the ventricular system and reabsorbed by the arachnoid villus.
What are the major lobes of the brain?
- Frontal lobe
- Parietal lobe
- Occipital lobe
- Temporal lobe
What cells produce myelin? Which belong to the CNS and which belong to the PNS?
- Oligodendrocytes (CNS) and schwann cells (PNS) are glial cells that produce myelin.
What 5 parts is the spinal cord split into?
- Cervical nerves
- Thoracic nerves
- Lumbar nerves
- Sacral nerves
- Coccygeal nerves
How many pairs of cranial nerves and spinal nerves do humans have?
- 12 pairs of cranial nerves
- 31 pairs of spinal nerves
