BSO6 Flashcards
Which lobes make up the cerebral cortex/brain?
Cerebrum (majority)
Brainstem
Cerebellum
What divides the cerebrum? And what are the two hemophears connected by?
Longitudinal fissure
Corpus Callosum
What are the functions of the Cerebrum?
Memory, cognition, language, thought, judgement, reasoning, problem solving, attention, consciousness, hearing, vision, motor, touch
What is the cerebrum made of and what is it known as?
Outer grey matter layer
Cerebral cortex
Frontal lobe - features, boundaries, functions
Largest lobe
Boundaries:
- central sulcus (frontal & parietal)
- lateral sulcus (frontal & temporal)
Action (mental & physical):
Planning, problem solving, motivation, judgment, decision making, impulse control, social behaviour, personality, memory, learning, reward, attention
Skeletal muscle movement, ocular movement, speech control, facial movement
what does the CNS begin as and when is it formed by?
neural tube and formed by week 4
which germ layer does the neural tube develop from?
Ectoderm
How many expansions (vesicles) develop in the neural tube?
three
Forebrain, Midbrain and Hindbrain
what is included in the forebrain?
cerebral cortex (telencephalon), diencephalon
what is the midbrain also known as?
mesencephalon
What is included in the hindbrain?
Cerebellum, pons, medulla
What is Spina Bifida?
a congenital defect of the spine in which part of the spinal cord and its meninges are exposed through a gap in the backbone, often causing paralysis of the lower limbs.
What are the four brain regions?
Cerebral hemisphere, Diencephalon, Cerebellum, Brain stem
What is in the grey matter of the CNS
mainly nerve cell bodies (short unmyelinated axons)
What do you call a collection of nerve cell bodies in the CNS?
Nucleus
What is the white matter of the CNS
myelinated axons
what are Gyri?
elevated ridges of tissue on the cerebral surface that are separated by shallow valleys (sulci)
- sulci divide each hemisphere into five lobes
what are fissures?
deeper valleys that are separate large regions of the brain
how many regions are in each hemisphere?
three
Cerebral cortex, Internal white matter, Basal nuclei
how are the hemisphere primarily concerned with the motor and sensory functions?
contralateral
What abilities does the left hemisphere specialise in?
language, maths, logic
What abilities does the right hemisphere specialise in?
emotions, artistic skills, visual-spatial ability
What does the diencephalon form?
central core of the forebrain
Which are the three major parts of the Diencephalon?
Thalamus, Hypothalamus, Epithalamus
Facts about the Thalamus
midline, symmetrical structure with a left and right half
- consists of bilateral egg-shaped nuclei
- forms superolateral walls of the 3rd ventricle
- major relay station for the brain
- involved in memory and emotions
Facts about the Hypothalamus
contains grouped nuclei that maintain key physiological functions:
- hormone secretion
- controls autonomic nervous system
- thermoregulation
- relates hunger, satiety, thirst
- sleep-wake cycle
- emotional functions
Facts about Epithalamus
most dorsal portion of diencephalon
- pineal gland extends from posterior border
- secretes the hormone melatonin
What is the Limbic System?
group of structures located on medial aspect of each cerebral hemisphere and diencephalon
What is the Limbic System responsible for?
- emotional behaviours
- interpretation of internal and external stimuli
What does the ventricular system refer to?
four hollow cavities in the brain
paired lateral ventricles, third ventricle, fourth ventricle
Where are the paired lateral ventricles?
deep within each hemisphere
Where is the third ventricle?
between the two halves of the diencephalon
Where is the fourth ventricle?
between the brainstem and the cerebellum
Ventricles are filled with
Cerebrospinal fluid (CSF)
What does the CSF provide?
mechanical cushioning for the brain & spinal cord
also acts as medium for chemical communication
Is the central canal of the spinal cord patent?
In most adults over the age of 30, however, the central canal is probably not patent
Where does the CSF in the central canal of the spinal cord drain?
The central canal communicates inferiorly with the subarachnoid space at the conus medularis, at teh superior aspect of the lumbar cistern, a reservoir of CSF that also contains the cauda equina and filum terminale
What are meninges ‘made of’?
three connective tissue membranes that enclose the brain and spinal cord
- dura mater, arachnoid mater and pia mater
What is between the layer within the meninges?
Subdural space:
- between dura mater and arachnoid mater
Subarachnoid space:
- between arachnoid mater and pia mater
- contains CSF and the blood vessels that serve the brain
What is the Dura Mater?
- outermost of 3 meningeal membranes covering brain and spinal cord
- strongest meninx, composed of thick, tough & inflexible connective tissue
The dura mater around the brain
- periosteal layer: outermost dural layer; merges with the inner surface of the cranial periosteum
- meningeal layer: innermost dural layer, which adheres tightly to the deep sulci & fissures of the brain
The dura mater around the spine
- only one dural layer, the meningeal layer
- continuous with meningeal layer of brain
Where can you find the falx cerebri?
dura mater separating the left from right hemisphere
Where can you find the falx cerebelli?
separates hemispheres from cerebellum
Where is the tentorium cerebelli?
covers/protects cerebellum
What is the function of the diaphragma sellae?
covers & protects the pituitary gland
Where are the venus sinuses found?
within dura mater
What do the venous sinuses drain?
venous blood from the cerebral veins, emptying the internal jugular veins
What extends into the venous sinuses?
small projections of arachnoid mater called arachnoid granulations
allowing CSF to enter the dural venous sinuses
what is the spinal dura attached to?
spinal arachnoid mater, known as the dural sac or thecal sac (ends blindly at S2 level
What is the space between the bony vertebrae and the spinal dura mater called?
epidural space
What does the epidural space contain?
soft padding of adipose tissue, lymphatics, spinal nerve roots, loose connective tissue, small arteries, dural venous sinuses, and a network of veins
Where is the epidural space the narrowest and widest?
Cx region (1-2mm)
L2-3 it widens to 5-6mm
How many pairs of nerves are in the Spinal cord?
31 pairs of nerves
Which nerve roots are sensory/motor?
sensory - dorsal roots
motor - ventral roots
What is in the grey matter?
cell bodies
dorsal horn: sensory
lateral horn: autonomic
ventral horn: motor
What is in the white matter?
axons
separated into funiculi by horns of grey matter
dorsal
lateral
ventral
divided into tracts
what is laminae of rexed ?
Rexed proposed a classification based on the 10 laminae or layers that were related to a function of each lamina. Laminae I-IV are concerned with exteroceptive sensation and comprise the dorsal horn of the spinal cord. These are the main layers that process pain
Laminae of rexed - 2
Substantia Gelatinosa
Laminae of rexed - 3-6
nucleus propius
Laminae of rexed - 7
clarke’s nucleus
Laminae of rexed - 8
ACST neuron synapses here
Laminae of rexed - 9
Lsct neuron synapses here
Major ascending tracts of the spinal cord
Spinothalamic, Spinocerebellar, DCML
Dorsal columns (gracile and cuneate fasciculi)
Anterolateral system (spinothalamic tract)
Major descending tracts of spinal cord
Corticospinal tracts (anterior and lateral)
Corticulbar
What receptors are in the spinothalamic tract?
Thermoreceptors and nociceptors located in free nerve endings
Modalities carried in the spinothalamic tract
Temperature, pain and crude touch
Where is the spinothalamic tract located within the spinal cord?
anterior and lateral funiculus
What does DCML stand for?
Dorsal Column Medial Lemniscus system
Receptors of the DCML
Mechanoreceptors; Golgi tendons, muscle spindles, ruffinis, pacinian corpuscles, merkel discs, meissners
Modalities carried in the DCML
Proprioception, vibration, 2 point discrimination, light touch
Level of decussation of DCML
Caudal medulla
Location of the DCML within the spinal cord
posterior funiculus (cuneate and gracile fasciculus)
Termination of the Spinothalamic tract
Primary sensory cortex of parietal lobe
Termination of DCML
Primary sensory cortex
Lateral Corticospinal tract - cells of origin
primary motor cortex - pre central gyrus
What information is carried in the Lateral Corticospinal tract
Motor for limb musculature
Termination of the Spinothalamic tract
Primary sensory cortex of parietal lobe
Ventral Corticospinal tract - cells of origin
primary motor cortex - pre central gyrus
What information is carried in the Ventral Corticospinal tract?
Motor for trunk musculature
Which are the three major arteries that supply the brain?
Anterior cerebral artery
middle cerebral artery
posterior cerebral artery
What is Anastomosis?
A cross-connection between adjacent channels, tubes
What do Anastomoses provide for arteries?
Alternative flow pathways to the superficial aspect of each hemisphere
What is the circle of willis composed of?
anterior cerebral arteries
anterior communicating arteries
internal carotid artery
posterior cerebral arteries
posterior communicating arteries
Which arteries are the major inputs to the circle of willis?
internal carotid artery and vertebral artery
Arteries of the brainstem - Midbrain
Basilar artery
Arteries of the brainstem - Pons
Basilar branches
Arteries of the brainstem - Dorsolateral medulla
posterior inferior cerebellar artery
Arteries of the brainstem - Anterior medulla
Anterior spinal and vertebral arteries
Where does most venous blood from the brain drain into?
dural venous sinuses
Where does the inferior sagittal sinus drain into?
straight sinus
Where do the superior sagittal and straight sinuses empty into?
Transverse sinuses which turn into sigmoid sinuses
What do the sigmoid sinuses become as they exit the skull?
internal jugular veins
What does the internal jugular vein drain into?
right atrium
Which blood do the internal jugular veins collect?
from the brain, superficial regions of the face & neck
Which veins form the brachiocephalic veins?
internal jugular vein and subclavian
Termination of the Spinothalamic tract
Primary sensory cortex of parietal lobe
What do the left and right brachiocephalic veins form?
superior vena cava (SVC)
