Anatomy Flashcards
How many pairs of spinal nerves are there?
31
How many pairs of cranial nerves are there?
12
What does the prosencephalon develop to become?
Telencephalon and diencephalon
What does the mesencephalon go on to become?
Mesencephalon
What does the rhombencephalon develop to become?
Metencephalon and myelencephalon
What is the diencephalon?
Hypothalamus and thalamus
What is the mesencephalon?
Midbrain
What is the metencephalon?
Pons and cerebellum
What is the myelencephalon?
Medulla oblongata
What is the telencephalon?
The cerebral hemispheres
Which three regions make up the brain stem?
Pons, medulla, cerebellum
What is the soma?
Cell body containing the nucleus
In which direction do dendrites carry information?
Towards the soma
In which direction do axons carry information?
Away from the soma
What are the 4 types of glial cell?
Astrocytes, oligodendrocytes, microglia and ependymal
Describe the role of astrocytes
Involved in maintenance of BBB, environmental homeostasis, CSF stabilisation
How do astrocytes strengthen the BBB?
Bind capillaries together to make it harder for chemicals to pass through gaps
Describe the role of oligodendrocytes
Produce myelin in the CNS
What is the node of Ranvier?
A gap in the myelin sheath between adjacent Schwann cells
Describe the role of microglia
Immune monitoring and antigen presentation
What do microglia do in response to infection?
Pull processes in a become macro-phage like in structre
Where are ependymal cells located?
Lining of ventricles
Describe the structure of ependymal cells
Ciliated cuboidal/columnar epithelium
Describe the composition of white matter
Axons (mostly myelinated) and support cells
Describe the composition of grey matter
Soma, glial cells, synapses and support cells
Where does sensory info arrive in the spinal cord
Dorsal horn
Where does motor info arrive in the spinal cord
Anterior/ventral horn
Where do sympathetics exit the spinal cord?
Lateral horn T1-L2
What are the inward projections on the brain called?
Sulci
What are the outward projections of the brain called?
Gyri
What are the two gyri a/w the central sulcus?
Pre- and post-central gyri
What are the outward projections of the cerebellum called?
Folia
Which structure in the ventricles absorbs CSF?
Microvilli
What forms the choroid plexus?
Ependymal cells and capillaries
tela choroidea
What connects the 3rd ventricle to the lateral ventricles?
Foramen of monroe
What connects the 3rd ventricle to the 4th?
Cerebral aqueduct
What is the name given to the point in the midline where the two side of the thalamus touch?
Interthamic adhesion
What is the corpus callosum
Large bundle of fibres which allow communication between hemispheres
How do the cerebral cortex and brainstem communicate?
Through white matter tracts in the internal capsule
Which structure covers the top of the corpus callosum?
Cingulate
What is the fornix?
A bundle of nerve fibres which act as the major output tract of the hippocampus
Where is the enteric nervous system located?
Oesophagus to rectum
What are the two plexuses in the enteric nervous system?
Myenteric plexus between layers of smooth muscle
Submucosal plexus in submucosa
Where do the dural venous sinuses drain into?
Internal jugular vein
What do Schwann cells do?
Produce myelin in the PNS
What are the two main types of neuron?
Unipolar and mutlipolar
Which type of axons are found in skeletal muscle?
Mulitpolar
Which type of axons are sensory?
Unipolar
Which root from the spinal nerve is smaller?
Posterior
Which type of signal passes through the anterior root?
Motor
Which type of signal passes through the dorsal root?
Sensory
What is the dermatome level of the male nipple
T4
What is the dermatome level of the umbilicus
T10
What is the dermatome level of the posterior scalp, neck and shoulder?
C2-C4
What is the dermatome level of the upper limb?
C5-T1
What is the dermatome level of the gluteal region, perineum and lower limb?
L1-Co1
Which is usually more superficial dermatome or myotome?
Dermatome
What are the spinal nerve roots of the cervical plexus?
C1-C4
What are the spinal nerve roots of the brachial plexus
C5-T1
What are the spinal nerve roots of the lumbar plexus?
L1-L4
What are the spinal nerve roots of the sacral plexus?
L5-S4
At what levels does sympathetic outflow pass through?
T1-L2
Where do sympathetic axons synapse for the heart?
Cervical paravertebral ganglia
Where do sympathetic axons synapse for the lungs?
Upper thoracic paravertebral ganglia
Where do sympathetic axons synapse for the abdominopelvic axons?
Prevertebral ganglia
How does parasympathetic outflow pass out of the CNS?
via CNs III, VII, IX, X
At what level does the spinal cord end?
L1/L2
What cone-shaped structure does the spinal cord make at the end?
Conus medullaris
What is the name of the thin connective tissue cord anchored to the dorsum of the coccyx?
Filum terminale
What are the 3 groups of arteries which supply the spinal cord?
Longitudinal arteries
Segmental arteries
Radicular arteries
How many major longitudinal arteries are there and what are their positions?
3
Two posterior and one anterior
What is the largest segmental artery called?
Great anterior segmental medullary artery
Artery of adamkeiwsz
Where do the segmental arteries to the spinal cord originate?
Vertebral, intercostal and lumbar arteries
Where are the radicular arteries to the spinal cord found
At the dorsal and ventral roots
What is the dorsal/medial lemniscus system for?
Fine touch and conscious proprioception
Where do fibres in the dorsal/medial lemniscus cross?
In the medulla
Where do axons in the dorsal/medial lemniscus synapse?
Nucleus gracillis - lower limbs
Nucleus cuneaus - upper limbs
Thalamus
What is the spinothalamic tract for?
Pain, temperature and deep pressure
Where do axons in the spinothalamic tract synapse?
Immediately at spinal cord
Thalamus
Where do fibres in the spinothalamic tract cross?
Immediately at the spinal cord level
What is the corticospinal tract for?
Fine, precise movement of distal muscles
Which two tracts does the corticospinal tract consist of?
Ventral
Lateral
Where do fibres cross in the corticospinal tract?
85% at the dessucation of the pyramids
15% segmentally when seeking out axon
Describe the pathway through the corticospinal tract
Cortex > internal capsule > midbrain > pons > medulla > spinal cord
What is the tectospinal tract for?
Input to cervical spinal cord to mediate reflex head and neck movements in response to visual stimuli
What is the reticulospinal tract for?
Several functions including regulation of voluntary movements
Pons fibres: facilitate extensor movements and inhibit flexor movements (medulla vice verca)
Where do fibres originate for the reticulospinal tract?
Reticular areas of pons and medulla
What is the vestibulospinal tract for?
Excitatory input to anti-gravity extensor muscles
Where do fibres for the vestibulospinal tract originate?
Vestibular nuclei of pons and medulla
How many lobes does the cerebellum have?
3 - Anterior, posterior and flocculus
Where is the cerebellum located?
In posterior cranial fossa below the tentorium cerebelli
What attaches the brainstem to the cerebellum?
Superior, middle and inferior peduncles
Which cerebellar peduncle I the biggest?
Middle
What structure splits the cerebellum in half?
Vermis
How many layer does the cerebellum have?
3
Outer/molecular
Middle/Purkinje
Inner/granular
Describe the outer layer of the cerebellum
Molecular
No cells but many synapses
Describe the middle layer of the cerebellum
Purkinje
Contains enormous neurons
Describe the inner layer of the cerebellum
Granular
Many tiny neurons (over 50% of neurons are here)
How do afferents enter the cerebellum?
Via the peduncles to the granular layers
How is afferent info processed in the cerebellum?
Sent from granular layer to purkinje cells to molecular layer then out of cerebellum
Where do efferent neurons synapse in the cerebellum?
On axons of purkinje cells
Is the cerebellum a contralateral or ipsilateral structure?
Ipsilateral
What symptoms result from unilateral lesions on the cerebellum?
Tremor
Weakness
Sensory loss
Loss of co-ordination
What symptoms result from bilateral lesions of the cerebellum?
Dysarthria
In-coordination
Wide gait
What is the basal ganglia?
Grey matter structures deep in brain which initiate and inhibit movements
What are the five parts of the basal ganglia?
Caudate nucleus Putamen Globus pallidus Subthalamic nucleus Substantia nigra
What makes up the striatum?
Caudate nucleus and putamen
What makes up the lenticular nucleus?
Putamen and Globus pallidus
What makes up the corpus striatum?
Caudate nucleus, putamen and Globus pallidus
What does the substantia nigra do?
Plays a role in reward and movement
What disease is a result of the degeneration of the dopaminergic neurons of the substantia nigra?
Parkinson’s disease
Is the basal ganglia a contralateral or ipsilateral structure?
Contralateral
What do lesions of the basal ganglia usually cause?
Change in muscle tone, dyskinesia, tremor, chorea, myoclonus
How does Parkinson’s present?
Akinesia, rigidity, resting tremor
What is pathologically affected in Parkinson’s disease?
Substantia nigra
Direct pathway
What is pathologically affected in Huntington’s Disease?
Basal ganglia
Cerebral cortex
Indirect pathways
How does Hungtinton’s Disease present?
Chorea and progressive dementia
What are the 4 extrinsic back muscles?
Levator scapulae, rhomboids, trapezius, latissimus dorsi
What are the 2 groups of intrinsic back muscles?
Erector spinae and transversospinalis
Where do the erector spinae muscles commonly attach?
Sacrum and iliac crest
What are the three erector spinae muscles called?
Iliocostalis
Longissimus
Spinalis
What movement is elicited by the bilateral contraction of transverospinalis and erector spinae?
Extend spine
What movement is elicited by the unilateral contraction of transverospinalis and erector spinae?
Lateral flexion
What movement is elicited by the contraction of psoas major and rectus abdominus?
Flexion of spine
Which joints are between articular processes of vertebrae?
Facet joint
What are the two parts of the intervertebral discs?
Annulus fibrosis
Nucleus pulposis
Which ligament connects the laminae of adjacent vertebrae?
Ligamentum flavum
Which ligament connected the posterior aspects of vertebral bodies/discs?
Posterior longitudinal ligament
What is the role of posterior longitudinal ligament?
Prevents over flexion of the spine
What connects the anterior aspects of the vertebrae/discs?
Anterior longitudinal ligament
What is the role of the anterior longitudinal ligament?
Prevents over-extension of the spine
What ligaments connectsspinous processes?
Supraspinous, inter spinous
Which vertebra has no vertebral body?
C1
What type of joint is the atlanto-occipital joint?
Synovial
Which vertebrae had the odontoid process?
C2
Which vertebra is the first palpable process in most people?
C7