Class 3 Flashcards
What are the meninges covering the CNS?
- dura mater
- arachnoid
- pia mater
What does the following brain cross-section look like:
horizontal (axial)
What does the following brain cross-section look like:
coronal
What does the following brain cross-section look like?
sagital
The forebrain includes what parts of the CNS?
- cerebrum (cerebral hemisphere)
- diencephalon
The midbrain includes what parts of the CNS?
upper brain stem
The hindbrain includes what parts of the CNS?
- medulla
- pons
- cerebellum
What are the seven main parts of the CNS?
- spinal cord
- medulla oblongata *
- pons *
- cerebellum
- midbrain *
- diencephalon
- cerebral hemisphere
* brain stem
What are the four sections of the spinal cord?
- cervical
- thoracic
- lumbar
- sacral
What are the primary cortical areas?
- motor cortex (frontal lobel, BA 4)
- auditory cortex (temporal lobe, BA 41)
- Broca’s speech area (frontal lobe, BA 44)
- visual cortex (occipital lobe, BA 17)
- somatosensory cortex (parietal lobe, BA 1-3)
BA = Brodmann’s area
band of white matter that connects the two cerebral hemispheres
corpus callosum
What are the six layers of cells in the human cortex (neocortex)?
- molecular layer
- external granular layer
- external pyramidal layer
- internal granular layer
- internal pyramidal layer
- multiform layer
allocortex
areas of the cortex with fewer cells than the neocortex
pyramidal cells
cells whose axons go to outer regions / spinal cord
granular (stellate) cells
receive sensory input from other neurons
A ring of structures around the brain stem and includes areas in both the telencephalon and diencephalon
limbic lobe
What are the major components of the limbic system? (8)
- olfactory pathways (“old nose brain”)
- amygdala
- hippocampus
- hypothalamus
- anterior nucleus of thalamus
- septum
- fornix
- prefrontal & cingulate cortex
This system is implicated in motivational processes, emotion & memory
limbic system
This brain structure is implicated in homeostatic processes & basic drives (e.g. feeding, fighting, fleeing, mating, maternal)
hypothalamus (several nuclei)
This brain structure has connections to the hypothalamus, but is not technically part of the CNS?
pituitary (master gland)
This brain structure integrates movement and control of posture.
basal ganglia
The basal ganglia consists of what three parts?
- Globus Pallidum (GP)
- Caudate
- Putamen
* Collectively known as corpus striatum
Describe loops of the basal ganglia.
Important inputs from cerebral cortex/outputs back (through thalamus) to cerebral cortex (“loops”). “Loop” involving frontal cortex & BG: Important role in motor control & cognitive processes (executive functions)
Describe input and communication of the thalmus (several nuclei).
All inputs to cerebral cortex (except some olfactory); first synapse in thalamus (a major “relay”)
What are the two parts of the hindbrain (rhombencephalon)?
- myelencephalon (medulla)
- metencephalon (pons & cerebellum)
This brain structure controls functions essential to life (respiration, heart rate), reflexive responses
medulla
Describe the sensory aspects of the medulla.
Contains ascending (sensory) tracts (e.g. medial lemniscus) and sensory nuclei (e.g. dorsal column nuclei) in dorsal portion and descending (motor) tracts (e.g. decussation of pyramidal tract) in ventral portion.
* Nucleus = cell bodies
Describe the cranial nerves of the medulla.
- Cranial nerves are similar to spinal nerves, only they exit from brain and supply primarily head structures.
- Some cranial nerves are only sensory (e.g. optic), some only motor (hypoglossal whose nucleus is in the medulla), some are mixed (e.g. facial nerve)
Name the input and output cells in the cerebellum.
- input: climbing fibers, mossy fibers
- output: purkinje cells, basket cells (inhibitory influence)
This brain structure is important for sensorimotor functions, movement and posture, and is implicated in some types of learning.
cerebellum
What is the structure of the cerebellum?
- cerebellar cortex (covering)
- deep nuclei
What are the afferent (from outside in) inputs of the cerebellum?
- auditory
- visual
- vestibular
- somatosensory (e.g. spinocerebellar tracts)
What are the efferent (from inside out) projections of the cerebellum?
- other brain structures (e.g. cerebral cortex)
- brain stem nuclei
- no descending tracts to spinal cord
What is the pons?
- An important area of synaptic integration
- Many nuclei receiving inputs from other brain sites
- Tracts “bridge” to cerebellum and elsewhere
Describe the structures of the midbrain (mesencephalon).
- Tectum
- superior colliculi: visual reflex
- inferior colliculi: auditory reflex
- Tegmentum
- substantia nigra: integrating movements
- red nucleus: basic body movements
- reticular formation: maintaining consciousness and controls arousal
Ventricles contain _____ _____ _____ which is produced in _____ _____ (lining of the ventricles).
cerebral spinal fluid; choroid plexus
_____ _____ _____ connects to the brain and spinal cord through conduits and provides support.
cerebral spinal fluid
This area of the spinal cord consists of gray matter (dense packing of cell bodies) and forms an H shape (dorsal and ventral horns).
inside (medial)
This area of the spinal cord consists of white matter: myelin of axons, arranged in tracts or pathways which are bundles of axons traveling together within the central nervous system.
* Note: Bundles of axons outside CNS are called nerves.
outside (lateral)
How are tracts named within the central nervous system?
From origin to termination
e.g. corticospinal tract
Spinal nerves enter the spinal cord in the _____ root and motor nerves leave the spinal cord in the _____ root.
dorsal; ventral
Dorsal areas associated with sensory processes;
ventral areas associated with motor processes
Both dorsal and ventral roots exit through notch in vertebral column and join into _____ _____ (mixed) to supply peripheral structures.
spinal nerve
body area innervated by single spinal segment - have segmental organization
dermatones
How are dorsal columns organized?
somatotopically
What are the steps in the development of the central nervous system?
- CNS begins as a thin sheet consisting of three cell layers:
- ectoderm (gives rise to neural plate)
- mesoderm
- endoderm
- Neural groove forms
- Walls of the neural groove (AKA neural folds) fuse, form neural tube
- Neural ectoderm (neural crest) will develop into PNS; mesoderm will develop into skeletal system and muscles
The neural plate consists of what two parts?
- neural tube (CNS)
- neural crest (PNS)
Describe how the neural tube transforms.
- Rostral end: brain (encephalon)
- forebrain (prosencephalon)
- midbrain (mesencephalon)
- hindbrain (rhombencephalon)
- Caudal end: spinal cord
- Space within tube (brain): ventricles filled with cerebrospinal fluid, cerebral aqueduct
- Space within tube (spinal cord): central canal filled with cerebrospinal fluid
Phylogenetic comparisons: how is the human brain different from other species?
- progressive corticalization
- increased folding
- progressive frontalization
