1.1 Nuts Bolts of the Brain Flashcards
What are the 2 main divisions of the Nervous system?
Central NS
Peripheral NS
Input into the CNS are ____ fibres
Output from CNS are ____ fibres
Pathways that are coming ‘INTO’ the brain are termed ‘afferent’
Pathways coming ‘OUT’ are termed ‘efferent’
What are the 2 divisions of Efferent pathways?
Somatic NS
Autonomic NS
What are the 2 divsions of the Autonomic NS?
Sympathetic and Parasympathetic NS
What neurons do the Somatic NS innervate and what does this control?
Somatic NS innervates motor neurons which controls skeletal muscles
What are the 3 most common imaging planes?
Label what each in on the CT below
Axial
Sagital
Coronal
Label the planes below
What plane is shown below?
What plane is shown below?
What plane is shown below?
Label the arrows and state the function of each
Basal Ganglia: motor control
Thalamus: relay motor and sensory signals to the cerebral cortex
Hypothalamus: releasing hormones, regulating body temp, daily physiological cycles
Cortex: largest site of neural integration, key role in attention, perception, awareness, thought, memory, language, and consciousness
Hippocampus: memory and emotion
What are depressions/fissures in the surface of brain called?
What is the ridge on the cerebral cortex called?
Sulcus
Gyrus (generally surrounded by one or more sulci)
What is grey matter and what is white matter?
Grey matter = neuron rich regions (cell bodies)
White matter = myelinated axons
What are collections of nerve cell bodies in the PNS vs CNS known as?
Cell bodies in PNS = Ganglia
Cell bodies in CNS = Nuclei
What structure comprise the Brainstem?
List their functions
Midbrain: motor movement (esp eye), auditory and visual processing takes place
Pons: relay signals from the forebrain to the cerebellum
Medulla: directly controls certain ANS responses such as HR, breathing, BV dilation and digestion
What structures are found in the forebrain and list the functions?
Forebrain
- Cerebrum (85% of the brain)
- Thalamus: processing centre for sensory information
- Hypothalamus: control centre for the ANS
What structures are found in the midbrain?
As we reach the topmost part of the brainstem how does this differ?
Midbrain: vital connection between the forebrain and hindbrain
Midbrain can be divided into:
- tectum
- colliculi
- tegmentum
- peduncles
Topmost part of brainstem does not have the tectum
What structures are found in the hindbrain and list the functions?
Hindbrain
- Pons: connects brain with spinal cord and cranial nerve nuclei
- Medulla oblongata: autonomic vital function such as heart rate and breathing
- Cerebellum: coordination
Label the anatomical landmarks (gyrus)
Label the anatomical landmarks
Label the 4 lobes of the cerebral cortex
List 4 functions of the frontal lobe?
motor function, problem solving, spontaneity, memory, language, initiation, judgement, impulse control, and social and sexual behaviour
List the functions of the Parietal lobe
Can be divided into two functional regions
- one involves sensation and perception
- the other is concerned with integrating sensory input, primarily with the visual system.
List the functions of the Temporal lobe
auditory perception, such as hearing and holds the primary auditory cortex
List 4 functions of the occipital lobe
Visual processing area of the brain, associated with visuospatial processing, distance and depth perception, color determination, object and face recognition, and memory formation
What are Brodmann areas?
Areas defined by cell histology and organisation, related to function.
What are the 2 halves of the brain called and how are they linked?
Cerebral hemispheres linked by the corpus callosum
What is the corpus callosum?
A large tract of white matter that seperates the right and left hemispheres
What is the corona Radiata?
Area of white matter immediately below grey matter of cortex
Where does the spinal cord begin and end?
Extends from the foramen magnum to L1 in the vertebral canal
(below L1 is the cauda equina)
Where do sensory vs motor neurons enter the ganglion
Sensory neurones enter in the dorsally (posterior) horn
Motor neurons exit through the ventral (anterior) horn
What is the centre and outer of the spinal cord made of?
How is each organised?
Central grey matter = neuronal cell bodies
- Organized into laminae of Rexed
Outer white matter = myelinated axons
- Organized into specific structure
What is the longest and widest nerve in the body and what are its nerve roots?
In what condition is this nerve of particular importance?
Sciatic nerve arises from roots of L4-S3 of the sacral plexus
Runs down the lower limb, clinically important in sciatica
Label the tracts of the spinal cord that nerve pathways run through on the image below
What are the 2 components of the posterior columns of ganglion?
Fasciculus gracilis
Fasciculus cuneatus
What are the 3 layers of the meninges?
Describe each
Dura mater:
- thick, tough, outer membrane in 2 layers
Arachnoid mater:
- thin membrane with thread-like processes that make contact with the pia mater
- contains arteries and is filled with CSF
- Increases in size to form cisterns
Pia mater
- Envelopes the contours of the brain and spinal cord
Label the image below
What are extensions of the dura mater?
What are the 3 important dural extensions mater
These are non-compliant membranes that divide the intracranial vault in various ways
3 Important:
- The falx cerebri
- The falx cerebelli
- The tentorium cerebelli
What secretes and modifies CSF?
What absorbs CSF?
Describe the circulation of CSF
Secreted by the choroid plexuses (modified ependymal cells) of the ventricles
Resorption in venous sinuses via arachnoid granulations
Describe the composition of CSF and list 3 main functions
Similar constituents to blood plasma BUT less albumin and glucose
Functions:
- bathe and cushion the brain against mechanical agitation
- reservoir for metabolic substrates for the brain
- dissolves & carries away products of metabolism from the brain
What is the function of the ventricles of the brain?
List the components of the ventricular system
The ventricles are lined by ependymal cells, which form a structure called the choroid plexus, this produces CSF and the ventricles transport it around the cranial cavity
Ventricular system
- 2 lateral ventricles
- third ventricle
- cerebral aqueduct
- fourth ventricle
Give 4 functions of the blood brain barrier?
1) physical barrier: prevents passage of molecules and cells into brain
2) protection: against toxins, pathogens
3) maintains a constant intracerebral chemical environment
4) facilitates and restricts molecules/drugs from the blood to the CSF
Give 2 features of the BBB that restrict molecules/drugs passing from the blood to the CSF
1) cerebral capillary endothelial cells have tight junctions
2) astrocytic foot processes
