Anatomy Flashcards
how many cranial and spinal nerves
12 pairs of cranial
31 pairs of spinal
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
how does the brain form
from the neural tube
at 4 weeks forms primary vesicles (pros, mes and rhomb -encephalons)
at 6-8 week form secondary vesicles
what does the telecephalon form
cerebral hemispheres
what does the diencephalon form
thalamus, hypothalamus
what does the mesencephalon form
midbrain
what does the metencephalon form
pons, cerebellum
what does the myelencephalon form
medulla oblongata
what makes up the brainstem
mid brain
pons
medulla oblongata
what makes up the diencephalon
thalamus + hypothalamus
what are the majority of neurones
multipolar with many dendrites and one axon
what is the soma of a neurone
contains the nucleus and cellular apparatus
what way is electric activity going in an axon
away from the cell body
what do glial cell do
support cells for CNS
what are the 4 types of glial cells
astrocytes, oligodendrocytes, microglia, ependymal cells
what do astrocytes do
support, maintain BBB, environment homeostasis
star shaped
what is the role of the BBB
prevents things in blood directly accessing parenchyma of the brain
is there connective tissue in the CNS
no- why you need glial cells
what is the role of oligodendrocytes
produce myelin in the CNS (not in PNS) (wrap cell membranes around axons to increase the speed of conduction)
what is the node of ranvier
a gap between two myelinated axon areas- APs skip from one node to the next
what is the role of microglia
(hemopoietic (bone marrow) origin)
immune monitoring and antigen presentation (when activates take on appearance of macrophages)
what are ependymal cells
ciliated cuboidal/ culomnar epithelium that line the ventricles
what is a gyrus, sulcus and fissure
gyrus- ridge in cerebral cortex
sulcus- groove in cerebral cortex
fissure- deeper than gyrus
what fissures does the brain have
lateral (2) and longitudinal
what is grey matter
has lots of neurones, cell processes, synapses and support cells
(forms outside of brain)
what is white matter
(medullary centre)
axons and their support cells
how can you identify the dorsal and ventral horns of the grey matter in the spinal chord
grey matter on inside
dorsal horn extends back towards the posterior surface of the spinal chord
ventral horn is a distance from the anterior surface of the spinal chord
what does the calcarine suclus demarcate
primary visual cortex
what is the corpus callosum
largest connection between the left and right hemisphere
a band of white matter
what is the fornix
band of white matter that goes into the hypothalamus
where is the 4th ventricle
sits behind the pons
where is the frontal lobe
lobe anterior to the central sulcus and superior to the lateral sulcus.
anterior to a line drawn from the central sulcus down to the corpus callosum
where is the parietal lobe
posterior to the central sulcus, superior to the lateral sulcus (and a backward extension of it), and anterior to a line from the parieto-occipital sulcus to the preocciptial notch
posterior to the frontal lobe and anterior to the parieto-occipital sulcus.
where is the occipital lobe
posterior to a line from the parieto-occipital sulcus to the preocciptial notch
posterior to the parieto-occipital sulcus.
where is the temporal lobe
inferior to the lateral sulcus (and a line extending the lateral sulcus posteriorly) and posteriorly by a line from the parieto-occipital sulcus and the preoccipital notch
what is the role of the insular lobe
role in the experience of pain
what are the three meninges from superficial to deep
Dura mater
Arachnoid mater.
-Subarachnoid space contains cerebrospinal fluid (CSF)
Pia mater.
what makes up the outer layer of the dura mata
the periosteum of the skull
what creates the subarachnoid space
pia mata follow the indentations of the brain but the arachnoid mata does not
what joins the lateral ventricles
communicate via 3rd ventricle (via intraventricular foramen)
what is the enteric nervous system
found in digestive system
controls motility in the muscles of the digestive system
what is the blood supply to the brain
internal carotid system- Common carotid -> internal carotid -> anterior cerebral artery -> (anterior communicating artery), middle cerebral artery
vertebro-basilar system- Subclavian arteries -> vertebral arteries -> unite forming the basilar artery -> anterior inferior cerebellar, superior cerebellar, posterior cerebral arteries(->posterior communicating artery)
circle of willis= Anastomosis between the anterior and posterior circulation
Polygonal anastomosis between:
Internal carotid artery (branch of the common carotid)
Anterior cerebral artery (branch of the internal carotid)
Anterior communicating artery (branch of the anterior carotid, connects left and right anterior cerebral arteries)
Posterior cerebral artery (branch of the basilar artery)
Posterior communicating artery (branch of the posterior cerebral, connects the three cerebral arteries on the same side)
what is the venous drainage of the brian
dural venous sinuses drain into the internal jugular vein
what makes up the PNS
cranial nerves and spinal nerves
what is a ganglion
collection of nerve cell bodies in the PNS (same thing in CNS called a nucleus)
how does information reach neurones
dendrites
whats the difference betwen multipolar ans unipolar neurones
multipolar: - 2 or more dendrites - all MOTOR neurones of skeletal muscle & ANS (symp and parasymp) - cell body in CNS
unipolar:
- double process
- aka pseudounipolar / SENSORY
- cell body in PNS
what are motor neurones
efferent
impulses towards body wall/ cavity/ organ
what are sensory neurones
afferent
impulses towards brain
what is a tract
collection of axons surrounded by connective tissue and blood vessels
what is single and mixed modalities
a tract can be single:
one of somatic motor, sensory, special sensory, symp, parasymp, visceral afferent
or mixed where different nerves together in one (most tend to be mixed)
what cranial nerves connect to CNS at forebrain
CN I and II
what cranial nerves connect to CNS at midbrain
III IV
what cranial nerves connect to CNS at pons
V
what cranial nerves connect to CNS at pontomedullary junction
VI, VII, VIII
what cranial nerves connect to CNS at the medulla
CN IX, X, XII
what cranial nerves connect to CNS at the spinal chord
XI
how do you remeber the modalities of the cranial nerves
some say mary money but my brother says big balls matter more
s= special sensory m= motor b= both
where in spine are the spinal nerve
intervertebral foramina
what do spinal nerves connect to
spinal chord segment at the same number (C1 at C1) via roots and rootlets
structures of the soma (body walll) via rami
what is the path of spinal nerves
spinal chord rootlets (ant and post) roots (ant and post) spinal nerve post and ant rami
what does the posterior rami do
is small, supplies the posterior body wall
what does the anterior rami do
bigger, supplies the anteriolateral body wall
what is the path of sensory axons from spinal nerves to chord
spinal nerve
posterior root
posterior rootlets
posterior horn of the spinal chord
what is the path of motor axons from chord to spinal nerves
anterior horn of spinal cord
anterior rootlets
anterior root
spinal nerve
what is the dorsal root ganglion
Location of cell bodies of primary afferent neurones
are roots mixed or single modality
single (as come from post or ant horn)
what does each spinal supply
general sensory supply to all structures
somatic motor supply to skeletal muscles
sympathetic nerve supply to the skin and to the smooth muscle of arterioles
what is a dermatome
area of skin supply sensory innervation from a single spinal nerve (and deeper structures)
what is a myotome
the skeletal muscles supplied with motor innervation from a single spinal nerve
(may be same as dermatome but not always)
what needs to be damaged for an area of skin to be numb
several adjacent spinal nerves as dermatomes overlap
what dermatome is the nipple
T4
what dermatome is the umbilicus
T10
what dermatome is the posterior scalp, neck and shoulder
C2-C4
what dermatome is the upper limb
C5-T1
what dermatome is the lower limb, gluteal region and perineum
L2-Co1
what forms nerve plexuses
ONLY anterior rami
what is the cervical plexus
C1-4
supplies posterior scalp, neck and diaphragm