Neuro Flashcards
How many lobes are there in the brain (basic)?
4
Name the lobes in the brain
Frontal, parietal, occipital and temporal
What is the frontal lobe’s function?
Voluntary contralateral motor control, control of speech and writing (from dominant sphere) and higher thinking centres
What is the parietal lobe’s function?
interprets sensations including pain, 2-point discrimination, pressure, size, shape and body part awareness (proprioception)
What is the occipital lobe’s function?
understanding visual images and written word meanings
What is the temporal lobe’s function?
understanding spoken words (Wernicke’s), sounds as well as memory and emotion
Name 4 prominent sulci found in the cerebrum
central sulcus, lateral sulcus, post-central sulcus, and per-central sulcus
What is another name for the lateral sulcus?
the Sylvius fissure
Name 3 prominent gyri in the cerebrum and their function
Precentral gyrus (PMC), postcentral gyrus (SSC) and superior temporal gyrus (auditory processing)
Where is the superior temporal gyrus found?
Inferior to the lateral sulcus
Where is the precentral and postcentral gyrus found?
anterior to the central suclus and posterior to the central sulcus respectively
What is the falx cerebri?
Tough piece of dura mater found in the medial longitudinal fissure that separates the 2 hemispheres
What is the tentorium cerebelli?
Tough dura mater seperating the occipital lobe from the cerebellum
What is the function of the Broca’s area of the brain?
Language production
Where is Broca’s area located?
Frontal lobe, dominant hemisphere (usually left), Brodmann 44
What is the function of Wernicke’s area of the brains?
Language comprehension
Where is Wernicke’s area located?
Posterior part of the superior temporal gyrus, dominant hemisphere (usually left), Brodmann 22
What is the theory of dominance?
Most cognitive processes are on one side of the brain e.g. Broca’s and Wernicke’s
What is the homunculus?
Contralateral inverted somatotropic representation of the body in motor and somatosensory cortex
Is the homunculus proportionally divided?
No, it is distorted. Beginning from the toes at the top of the hemispheres, it moves up the body as it moves down the brain generating an upside-down man with arms raised and a flipped face. His lips, face, hands and feet are disproportionally large.
What is the rule in terms of the cortex and body part innervation?
Size of area in the cortex = degree of innervation to that body part
Function of the ventricles?
Produce and transport CSF
Function of CSF?
Protects brain and provides a stable chemical environment
What produces CSF?
Ependymal cells from the choroid plexus
Go through the route CSF takes in the brain
Produced (mostly) in the lateral ventricles, though the foramen of Monroe to the 3rd ventricle, through the cerebral aqueduct to the 4th ventricle and finally into the spinal canal and sub arachnoid cistern
What is the corpus callosum?
Large white matter structure made up of commisural fibers (fibers that connect the hemispheres)
Describe it’s basic anatomy
Small rostrum (beak-like), genu (knee), body, splenium
2 major divisions of the corpus callosum and what do they connect?
Forceps minor connects frontal lobes, forceps major connects occipital lobes
What are 5 functions of the brainstem?
Special senses, sensory and motor control for head and neck via CNS, autonomic regulation of the body, regulating consciousness, pathway between brain and spinal cord
Where is the midbrain located?
Around the cerebral aqueduct
3 divsions of the midbrain
o Tectum:
-Dorsal part of midbrain (most superior)
-Superior colliculus – visual processing
-Inferior colliculus – auditory processing
o Tegmentum:
- Ventral part of midbrain (most inferior)
- Contains periaqueduct grey, substantia nigra, red nucleus
o Cerebral peduncles (crus cerebri):
- Most anterior part of midbrain
- Everything in midbrain apart from tectum (includes tegmentum)
-Contains ascending and descending tracts
Punction of the pons
o Function = bridge to cerebellum
o Communication pathway between L and R cerebral hemispheres (striated appearance = corticopontocerebellar fibres)
o Posterior pons = rhomboid fossa = floor of 4th ventricle
o Pontocerebellar communication – inferior and middle cerebellar peduncles
Function of the medulla
o Most caudal part of brainstem -> connects pons to spinal cord through foramen magnum
o Anterior median fissure separates pyramids until they decussate – pyramids = descending tracts
o Posterior surface – posterior medial sulcus separates ascending tract (fasciculus and gracilis)
What are the 2 main divisions of the skull?
Calvarium (top part) and cranial (bottom part)
How many bones are there in the skull?
6: 1 frontal, 2 parietal, 2 temporal and 1 occipital
What are the sutures in the brain?
Coronal which connects the frontal and parietal bones, saggital which connects the parietal and temporal bones, lambdoid which connects the parietal and occipital bones
List the 9 openings in the skull and their nerves
o Cribiform plate – olfactory nerve
o Optic canal – optic nerve
o Superior orbital fissure – oculomotor, trochlear, ophthalmic trigeminal, abducens
o Foramen rotundum – maxillary trigeminal nerve
o Foramen ovale – mandibular trigeminal nerve
o Lacerum – internal carotid artery
o Internal acoustic meatus – facial, vestibulocochlear
o Jugular foramen – glossopharyngeal, vagus, accessory
o Hypoglossal canal – hypoglossal
Describe the meninges in the brain
o Dura mater – tough fibrous outer layer, falx cerebri + tentorium cerebelli, forms sinuses (cerebral venous drainage)
o Arachnoid mater – middle layer, transfers CSF from brain to bloodstream, major brain blood vessels lie in sub-arachnoid space
o Pia mater – layer covering brain, fuses with ependymal cells in ventricles to form choroid process
Describe and explain the BBB
formed by tight junctions between endothelial cells and astrocytic foot processes and protects brain from blood hcemical composition fluctuation by the addition of toxin
What is the arterial supply to the brain?
Internal carotid artery - branches into ophthalmic, posterior communicating, anterior and middle cerebral arteries.
Vertebral artery - arises froms ubclavian to converge and form the basilar artery
Go through the Circle of Willis
o Basilar artery – supplies pontine, cerebellar and posterior cerebral artery
o Posterior cerebral artery – supplies occipital lobe
o Posterior communicating artery – connects posterior and middle cerebral artery
o Middle cerebral artery – supplies lateral region of brain (temporal lobe)
o Anterior communicating artery – connects bothz anterior cerebral artery
o Anterior cerebral artery – supplies medial region of brain (frontal/parietal lobe)
What is a Berry aneurysm?
bulge in the blood vessel at the junction between cerebral arteries and circle of Willis (increased risk of haemorrhagic stroke)
Go through the venous drainage of the brain
o Venous blood collects between 2 layers of dura mater – sinuses
o 3 sinuses – superior/inferior sagittal and straight -> drain into transverse sinus
o Transverse sinus drains into internal jugular vein
o Superficial veins = superior, middle, inferior vs deep veins = great cerebral vein
Go through the origin, where it leaves the skull and special sensation function of each CN
• CNI – olfactory:
o Doesn’t arise from brainstem
o Leaves skull via cribiform plate
o Special sensation function – sense of smell
• CNII – optic:
o Doesn’t arise from brainstem
o Leaves skull via optic canal
o Special sensation function – sense of vision
• CNIII – oculomotor:
o Airses from midbrain
o Leaves skull via superior orbital fissure
o Motor function – innervates all muscles of the eye apart from lateral rectus (VI) and superior oblique (IV)
• CNIV – trochlear:
o Arises from midbrain
o Leaves skull via superior orbital fissure
o Motor function – innervates superior oblique muscle
• CNV – trigeminal:
o Arises from pons
o Opthalmic division:
Leaves skull via superior orbital fissure
Sensory function – sensation above nose
o Maxillary division:
Leaves skull via foramen rotundum
Sensory function – sensation between nose and mouth
o Mandibular division:
Leaves skull via foramen ovale
Sensory function – sensation below mouth
Motor function – innervates muscles of mastication
• CNVI – abducens:
o Arises from pons
o Leaves skull via superior orbital fissure
o Motor function – innervates lateral rectus (abduction of eyeball)
• CNVII – facial:
o Arises from pons
o Leaves skull via internal acoustic meatus
o 5 divisions – temporal, zygomatic, buckle, mandibular, cervical
o Motor function – innervates muscles of facial expression
o Special sensory function – sense of taste for anterior 2/3 of tongue
o Parasympathetic function – submandibular and sublingual glands
• CNVIII – vestibulocochlear:
o Arises from pons
o Leaves skull via internal acoustic meatus
o Sensory function – cochlear nerve = auditory, vestibular nerve = balance
• CNIX – glossopharyngeal:
o Arises from medulla
o Leaves skull via jugular foramen
o Sensory function – sensory information for oropharynx and carotid bodies
o Special sensory function – sense of taste for posterior 1/3 of tongue
o Motor function – innervates stylopharyngeus muscle
o Parasympathetic function – parotid gland
• CNX – vagus:
o Arises from medulla
o Leaves skull via jugular foramen
o Sensory function – laryngopharynx and superior part of larynx (superior laryngeal)
o Parasympathetic function – heart and GI tract
o Motor function – innervates the muscles of the pharynx and larynx (via superior and recurrent laryngeal muscles)
• CNXI – accessory
o Arises from medulla
o Leaves skull via jugular foramen
o Motor function – innervates sternocleidomastoid and trapezius muscles
• CNXII – hypoglossal
o Arises from medulla
o Leaves skull via hypoglossal canal
o Motor function – innervates intrinsic and extrinsic muscles of the tongue
What is the mnemonic to help remember the CNs?
Oh Oh Oh To Touch And Feel Very Good Velvet. Such Heaven!
What is the function of the vertebral column?
Protect spinal cord, carry body weight above pelvis and act as a central axis
Break down vertebral column by sections
7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral and 4 fused coccyx (33 in total)
What is the vertebral body?
weight bearing portion of vertebrae lined with hyaline cartilage
What is the vertebral arch?
Pedicles (first part), transverse process (sides of pedicles and connect to ribs), lamina (connects pedicles to spinous process) and spinous process (projects inferiorly and site of muscle attachment)