3200 Midterm

where does fertilization and implantation occur

fertilization in the fallopian tube, implantation on the uterine wall

describe the fate of the inner cell mass and trophoblast during the second week of development

differentiation occurs, fluid accumulates in the inner cell mass which pushes the trophoblast and inner cell mass together

gastrulation

formation of the trilaminar embryo (ectoderm, endoderm, mesoderm)

three layers of epiblast and 2 anatomic structures from each

ectoderm, skin and hair
endoderm, gut lining, glands of digestive tract
mesoderm, heart, kidney

neurlation

epiderm differentiates, ectoderm thickens to form the neural plate, neural groove and neural fold form, neural folds form a tube, surface ectoderm reforms over, neural tube closes towards the head and tail

developmental events at the end of week 1

fertilisation, cleavage, compaction, formation of blastocyst

blastocyst

outer cell mass, trophoblast, and inner cell mass, embryoblast

developmental events at the end of week 2

implantation and differentiation of blastocyst, formation of bilaminal embryo

formation of the bilaminar embryo

fluid accumulates in the inner cell mass which pushes the trophoblast and inner cell mass together

developmental events at the end of week 3

bilayer, pit forms and streak forms towards the tail, gastrulation, formation of notochord, neurulation begins

bilayer embryo

epiblast and hypoblast

how does gastrulation work

cells divide and migrate towards the primitive streak, replace all hypoblast cells to create endoderm, dive down again to create mesoderm

developmental events at the end of week 4

head and tail end closed, formation of cylindrical body plan

superior

above /cranial

inferior

below / caudal

anterior

in front of / ventral

posterior

behine / dorsal

medial

inner side

lateral

outer side

proximal

closer to the origin

distal

farther from the origin

superficial

toward or at the body surface

deep

away from body surface

ipsilateral

on the same side

contralateral

on opposite sides

directional anatomy of the brain (clockwise from top)

dorsal, caudal, ventral, rostral

directional anatomy of the brain (clockwise from top) at midbrain junction

rostral, dorsal, caudal, ventral

coronal/ frontal plane

dorsal and ventral portions

transverse plane

cranial and caudal, horizontal

sagittal plane

left and right

basic tissue types on x rays

bone is white, air is black, muscle, fat and fluid is grey

basic tissue types on computed tomography (CT) scan

bone is white, air is black, muscle, fat and fluid is grey

basic tissue types on MRI T1

CSF is dark, gray metter is gray, white matter is white

basic tissue types on MRI T2

CSF is bright, gray matter is gray, white matter is darker

Central nervous system

brain and spinal cord

peripheral nervous system

outside the brain and spinal cord

sensory input

into the CNS (afferent)

integration

processes and interprets sensory input

motor output

exiting the CNS (efferent)

5 embryonic divisions of the brain

prosencephalon into diencephalon and telencephalon, mesencephalon, rhombencephalon, spinal cord

cephalic flexture

at midbrain

cervical flexture

junction of hindbrain and spinal cord

secondary brain vesicles

telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon

describe the differentiation of neural epithelial cells

end of 6 weeks
closer to surface ectoderm form interneurons, alar plate,
further from surface ectoderm forms basal plate and motor neurons, basal plate

sulcus limitans

where basal and alar plate differentiate differently

mantal

area close to neuroepithelial cells, future grey matter

ventricles of teh brain

lateral ventricles, third ventricle, fourth ventricle, spinal canal

neurons

large cell body with multiple projections

oligodendrocyte

myelinate several axons in the CNS, from neuroepithelial cells, wrap around axons

schwann cell

myelinate single axons in the PNS, from neural crest cells

astrocyte

star shaped, derived from neuroepithelial cells, foot like projections attach to blood vessels

microglial cell

thin nuclei, derived from mesoderm

ependymal and choroid epithelial cells

line ventricles, derived from neuroepithelial cells

main divisions of brain and embryological origin: cerebral hemisphere

telencephalon, forebrain

main divisions of brain and embryological origin: diencephalon

diencephalon, forebrain

main divisions of brain and embryological origin: midbrain

mesencephalon

main divisions of brain and embryological origin: pons

ptencephalon

main divisions of brain and embryological origin: medulla

myelencephalon

main divisions of brain and embryological origin: cerebellum

metencephalon

structural components of a neuron

dendrites that bring information into the cell body, cell body, synapse, axon, terminal buttons

multipolar neuron

many projections coming off cell body

bipolar neuron

two processes coming off the cell body

unipolar / pseudounipolar

one process coming off the cell body

neuroglial cells

cells that support neurons

satellite cells

surround neuron cell bodies in PNS, derived from neural crest cells

structure of peripheral nerve

two way traffic, going into periphery and CNS, each surrounded by myelin or Schwann cells, capillaries and blood vessels bring nutrients and remove waste

nerve repair mechanism

repaired in PNS as long as schwann cells remain, macrophage cleans, axon sprout new ends guided by schwann cells, axons reform and go back to where it was

paresthesia

sensory, abnormal sensation

numb

sensory, absent sensation

paresis

partial or incomplete paralysis

paralysis

loss of voluntary moevement

functions of central nervous system

integrative and control centre

functions of peripheral nervous system

communication lines between the CNS and the rest of the body

functions of sensory (afferent) divisions PNS

impulses from receptors to CNS

functions of motor (efferent) division PNS

impulses from CNS to effectors

somatic nervous system

voluntary motor, CNS to skeletal muscles

automatic nervous system

involuntary motor, CNS to cardiac muscles, smooth muscles, glands

sympathetic division

fight or flight response

parasympathetic division

housekeeping, rest and digest

visceral sensory

taste adn smell

somatic sensory

hearing, equilibrium, vision

fissures

large crevasses which divide the cerebral hemispheres

transverse cerebral fissure

cerebral hemisphere from cerebellum

longitudinal fissure

separates right and left hemispheres

sulci

shallow grooves on the surface

gyri

twisted ridges or surface holds

central sulcus

separates frontal and parietal love

parieto-occipital sulcus

separates parietal lobe and occipital love

components of spinal nerve

dorsal root, ventral root with motor neurons, spinal nerve

spinal nerve

gathering of motor and sensory

dorsal root ganglian

swelling of nerve, derived from neural crest cells

cervical nerve number

c1-8

thoracic nerve number

t1-t12

lumbar nerve numbers

l1-l5

sacral nerve

s1-s5

intervetebral foramen

lateral opening where spinal nerves pass through

how are cervical nerves named

name is of vertebrae below, c8 is named by vertebrae above

where does the tail exit

s1-2

plexus

fibres merge and split, if one nerve is damaged it causes partial loss

dermatome

sensory area supplied by a spinal nerve