Download 2. Nervous system 1 - Meninges: Dura mater, subdural space

2. Nervous system 1
- Meninges: Dura mater, subdural space, arachnoid membrane, subarachnoid membrane,
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pia mater
CSF produced by choroid plexus.
Spinal cord grey inside, white outside
Great matter is neutron cell bodies, white matter is nerve fibres (oligodendrocyte)
For large diameter axons, myelin increases the speed of the nerve impulse.
Nerve fibre covered by endoneurium, endoneurium covered by perineurium, perineurium
covered by epineurium.
CTLS (cervical, thoracic, lumbar, sacrum) 8,12,5,5
3. Nervous system 2
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Sensory join CNS via dorsal root, motor join at ventral root
spinal afferents have cell bodies in PNS, spinal efferents have cell bodies in CNS
12 pairs of cranial nerves
Somatic has one neuron, sympathetic has two neutron
Sympathetic- Grey ramus, white ramus.
Parasympathetic- Craniosacral outflow (rest and digest), sympathetic- Thoracolumbar
outflow (Fight and flight).
Para- Long, short
Sympatheic- Short, long
4. Embryology 1 and 2
- Blastocysts has two cell types: Inner cell mass (us) and trophoblast (contribute to life
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support system of embryo)
Germ layers: Ectoderm, mesoderm, endoderm
Germ layers form by process of gastrulation
Inner cell mass splits into epiblast (embryo) and hypoblast.
Epiblast migration form amniotic cavity
Hypoblast migration form yolk sac
At this stage, embryo is at where the two bubble touch.
Gastrulation: Start when a small portion of epiblast start to change. In midline, a line of
thickened cells appear (primitive streak), primitive streak form primitive groove.
Cells of epiblast migrate medially and into primitive groove and invade hypoblast and
create a new layer where the hypoblast was. ENDODERM is formed.
Later, cells move into space between epiblast and endoderm, forming MESODERM.
Cells left in epiblast become ECTODERM.
Fates of other cells moving through primitive groove: Posteriorly is Extra-embryonic
mesoderm, lateral mesoderm, paraxial mesoderm and most anteriorly is notochord.
Cells that form notochord has passed through primitive node.
Primitive groove now disappear after it instructed all cells and formed notochord.
Ectoderm gives rise to epidermis and nervous system.
Notochord induces ectoderm to form neural plate, neural plate form neural groove,
neural groove form neural tube. When neural tube formed, neural crest at top of neural
tube released and migrate away to form a wide range of structure.
Neural tube front end swell and form vesicles, vesicles give rise to brain, rest is spinal
cord.
- Mesoderm divided into paraxial mesoderm(closest to notochord), intermediate
mesoderm, lateral mesoderm(furthest from notochord)
- Paraxial mesoderm form dermis, axial skeleton and limb muscles.
- Paraxial mesoderm next to notochord start to get swelling called somitomeres. As
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embryo grow, it extend downwards. At 20 somitomere stage, the eighth pair first break
free and become somite. Somitomere 1-7 never become somite. All below 8 eventually
become free living block of somite.
Development of somite: Somite split into dermomyotome and schlerotome.
Dermomyotome then split into dermotome and myotome. Dermotome give rise to
dermis. Myotome give rise to muscles. Sclerotome give rise to axial skeleton.
Appendicular skeleton come from lateral mesoderm.
Pharyngeal arches: Embryo has Pharyngeal arches.
Lateral plate mesoderm form limb, muscles, bone and connective tissue. Limb is
initiated by mesoderm, then controlled by ectoderm
Digit development: Feet and hands start as flat plat, then form the hand by killing cells in
zone between fingers (apoptosis).
Endoderm: form organ along with mesoderm.
Endoderm gives rise to epithelial lining of organs.
Formation of coelum: Lateral mesoderm split, top layer is somatic mesoderm, bottom
layer is splanchnic mesoderm. Somatic mesoderm and ectoderm give rise to muscle.
Splanchnic mesoderm and endoderm form viscera. Splanchnic mesoderm and
endoderm bring to the midline and a hole in the middle which is gut, the mesoderm form
muscle walls outside gut. Front end is stomadeum, posterior end is proctodeum. Oral
plate that separate fore gut from stomadeum breaks, oral cavity forms. Proctodeum is
single opening to outside. Anus sealed by cloacal membrane. Allantois forms as branch
of the hind gut. Between allantois and hind gut is urorectal septum. The urorectal
septum grows backwards and form two opening. First opening from allantois is urinary
system. Second opening is rectum.
Allantois: stores nitrogenous waste in some species.
Allantois gives rise to bladder and urogenital tract.
As gut forming, heart also forming too.
Heart: formed from lateral splanchnic mesoderm. Splanchnic mesoderm forms form
bilateral tubes. Two tubes come together in midline, forming heart. Heart formed is
tubular heart, like fish heart. We need four chamber with two separate circulation. Tube
lengthen and fold upon itself, making space to develop two pairs of chambers. Blood
able to flow from right atrium to left atrium. This is short circuit.
Gut need to retract before purse string close it off.
Development of viscera: Endoderm interact with mesoderm.
Intermediate mesoderm give rise to urogenital system. We grow three types kidney.
12. Muscular system
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Skeletal striated, cardiac striated, smooth
Muscle- endomysium, perimysium, epimysium, deep fascia
Connective tissue meet up bone called tendon
Intermuscular septa, fascial compartments, retinacula (fascia down to ankle)
Aponeurosis: Tendon found in muscle with long spindle fibre
Raphe: Muscle at midline body
Fascial sheath: Muscle get blood and nerve supply has covering of fascial sheath
Synovial tendon sheaths: Muscle that go digit and form tendon
Fusiform: Biceps Brachii