Part 1 of 6 Anatomy Flashcards
Describe the outflow of the parasympathetic nervous system.
See F375 - Parasympathetic NS
· No PSNS in cervical , thoracic, lumbar regions, only in brain and sacral area
- Cranio-sacro output:
o Cranial nerves with a PSNS component = 3, 7, 9, 10 → head, neck and thoracic
o Sacral nerves with PSNS component = S2, S3, S4 → affect pelvic organs
Describe the outflow of the sympathetic NS.
See F376 - Sympathetic NS outflow
- Thoracic-lumbar output
o T1 – L2 → innervation of head and neck
o No cervical or cranial or sacral
· SNS nerves next to spinal chord – form a sympathetic chain (autonomic ganglia) → synapse with post-synaptic ganglia of SNS
Describe the structural and functional divisions of the nervous system.
See F372 - Structural and functional divisions of the nervous sys. (MM3)
Functional Division of the NS
- Somatic NS = external environment
- Autonomic NS = internal environment
Explain what the grey and white matter in the central nervous system consists of.
Arrangement of Central Nervous System
- Made of neuronal and non-neuronal (glial) cells, which make grey and white matter
o Grey: Cell bodies
§ Spinal grey horns
§ Cortex of cerebrum
§ Basal ganglia
§ Nuclei
o White: Myelinated neuronal fibres (axons & dendrites)
§ Association fibres
§ Commissural fibres
§ Projection fibres
Explain the types of white matter.
- Types of white matter:
o Association fibres: interconnect neural areas of cortex within single hemisphere
o Commissures: connect hemispheres, e.g. corpus callosum, thick band of white matter – connects cerebral hemispheres
o Projection fibres: link cortex to diencephalon, brain stem, cerebellum and spinal chord
(F377 - Types of white matter)
Identify and be able to pinpoint these structures:
- Corpus callosum
- Corona radiata
- Basal nuclei:
- Caudate
- Putamen
- Globus pallidus
- Internal capsule
- Projection fibres
- Decussation of pyramids
- Longitudinal fissure
- Lateral ventricle
- Fornix
- Third ventricle
- Thalamus
- Pons
- Medulla oblongata
See the rest of F377 - Types of white matter (MM4-5)
Describe structural divisions of the brain, detailing the components of the forebrain, midbrain and hindbrain.
See F378 - Divisions of the brain.
Extra Information
· Brain has 3 regions: forebrain, midbrain, hindbrain → formed during neurulation from dilations of neural tube – all 3 components have a central cavity
o Hindbrain = cerebellum, pons, medulla
o Forebrain = telencephalon and diencepalon
§ Majority of diencephalon is thalamus, lower part is hypothalamus
§ Hypothalamus located just above brain stem and mid-brain
§ Diencephalon is attached to midbrain
· Penduncles attach the cerebral hemispheres to the brain stem (made of white matter)
Be able to identify and understand the basic function of these structures:
- Cerebrum
- Cerebellum
- Diencephalon
- Hypothalamus
- Mesencephalon
- Pons
- Medulla oblongata
- Cerebellum
See F378 - Divisions of the brain.
Describe the basic structure of the diencephalon and the functions that it controls.
Diencephalon
- Thalamus, hypothalamus, epithalamus, retina
See F379 - Diencephalon components and functions
The cerebral hemispheres are marked with folds. What are the names of these fissures?
These fissures are called sulci and gyri. They develop due to brain development in skull – not enough space, brain folds over itself.
Sulci (sulcus) = Depressions
Gyri (gyrus) = Elevations
Name and identify the major:
- Fissures
- Gyri
- Sulci
Fissures
- Transverse fissure - separates the cerebellum from the hemispheres
- Longitudinal fissure - separates the 2 hemispheres
Sulci + Gyri
- Calcarine sulcus = primary visual area
- Major sulcus (aka central sulcus) [blue line], separates pre-central gyrus and post-central gyrus –> also is the border for parietal and frontal lobes
- Parieto-occipital sulcus [green line] –> also is the border for the parietal and frontal lobes
- Lateral sulcus (aka Sylvian fissure) [yellow line] –> also is the border for frontal and temporal lobes
Also other major sulci and gyri are shown in the figure indicated.
See F380
Name the lobes of the brain and briefly describe the function of each.
See F381 - Brain lobes and functions.
Describe the ventricular system of the brain.
Ventricular System of the Brain
See F382 - ventricular system of brain
- Lateral ventricle:
o Frontal lobe – anterior horn of lateral ventricle
o Parietal lobe – body of lateral ventricle
o Occipital lobe – posterior horn of lateral ventricle
- Third ventricle
o Ventricle of diencephalon – located between the 2 thalamus
o Open to the lateral ventricle via the interventricular foramen
- Cerebral aqueduct
o Joins the third ventricle to the fourth ventricle
- Fourth ventricle
o Continues from the aqueduct through the spinal chord into a structure called the central canal
Be able to point out these major structures in the brain stem:
- Cerebral peduncles
- Cerebellar peduncles
- Superior (midbrain)
- Middle (pons)
- Inferior (medulla)
See F383 - Cerebral and cerebellar peduncles.
Understand and memorise this picture of brain stem gross anatomy. Can you sketch the structure?
See F384 - Brain stem gross anatomy
Describe the major features of the spinal cord.
See F385 - Spinal cord major features.
How many pairs of spinal nerves are there?
Are spinal nerves sensory or motor?
- 31 pairs of spinal nerves
- Mixed = both sensory and motor
Describe the major features of a transverse section of the spinal cord.
See F386 - transverse section spinal cord.
Briefly describe the pathways which make up the sensory pathways.
Sensory pathways can be divided into conscious and unconscious sensation.
Conscious Sensation: (Clinically most important)
- These concious pathways transmit impulses from thalamus to sensory cortex for conscious interpretation
- Dorsal column-medial lemniscus pathway (DCML)
- FAsciculus cuneatus
- Fasciculus gracilis
- Medial lemniscus
- Antero-Lateral System (ALS)
- Lateral spinothalamic tract
- Anterior/Ventral spinothalamic tract
Unconscious Sensation:
- This pathway stretches to cerebellum
- Spino-cerebellar tracts
- Dorsal spinocerebellar tract
- Cuneocerebellar tract
- Ventral spinocerebellar tract
(See MM6)
Describe the function of the Dorsal column-medial lemniscus pathway (DCML).
DCML
- Transmit mechanical sensations into sensory info for:
- Discriminative touch – fine touch, pressure, movement detection
- Proprioception
- Vibration
(MM 7)