Chapter 2: The Nervous System's Functional Anatomy Flashcards
Phenotypic plasticity
individual capacity to develop more than one phenotype
Afferent nerves
incoming sensory information
Efferent nerves
outgoing information from the CNS; ie. parasympathetic & sympathetic nervous systems
Meninges (3)
3 layers of protective tissue that in case the brain and spinal cord; dura mater, arachnoid, pia mater
Dura Mater
tough outer layer of the meninges; a loose sac
Arachnoid
ultra thin sheet that follows contours of the brain
Pia Mater
tough membrane of connective tissues clinging to the brains surface
Subarachnoid space
between the arachnoid and pia mater; a layer that contains cerebrospinal fluid (CSF)
Cerebrospinal fluid
clear solution of sodium chloride and other salts that fills the ventricles and protects the brain
Medial vs Lateral orientation
Towards the midline vs towards the sides
Anterior vs Posterior orientation
front vs back
Dorsal vs ventral orientation
top vs bottom
Coronal Cut
cut vertically from the crown down, yielding a frontal view
Horizontal Cut
cut horizontally and enables a dorsal view
Sagittal cut
cut lengthways from front to back and enables a medial view
Cerebral cortex
thin, heavily folded film of nerve tissue that is the outside layer of the forebrain
Temporal lobe
side of the brain; involved in hearing, language and music
Frontal lobe
executive functions & decision making
Parietal lobe
top of the skull; directing movements towards a goal or task
Occipital lobe
back of the skull; vision
Gyri
bumps in the cortex
Sulci
groove in brain matter; central sulcus is the line from ear to ear
Longitudinal fissure
line down the centre (front to back) of the brain
Grey matter
composed predominantly of cell bodies and capillary blood vessels that modify information or support this activity
White matter
fat sheathed neuronal axons that form connections between brain cells
Ventricles
contain CSF and may maintain metabolism in the brain; the CSF flows between the 4 ventricles and in the cerebral aqueduct
Corpus Callosum
band of nerve matter with 200m nerve fibres that connects the two hemispheres and allows for communication
2 main types of cells in CNS
1) Neurons: major functions
2) Glial: aid and modulate neuronal activities
Nuclei
group of cells forming a cluster that forms a functional grouping
Nerve vs Tract
collection of axons coursing together outside (Nerve)/inside (tract) of the CNS
Brain stem
central structure of the brain that contains the hindbrain (motor), midbrain (sensory) and the diencephalon (integrative); responsible for most unconscious behavior
Hindbrain
contains the pons, medulla oblongata, reticular formation and cerebellum; controls most movement; oldest evolutionarily wise
Cerebellum
responsible for fine movements; larger in animals who require more (ie. elephants)
Reticular formation
nuclei and fibre pathways mixed (net-like); associated with sleep-wake and behavioral arousal
Pons
the bridge from the cerebellum to the brain; controls body movements
Medulla oblongata
breathing, cardiovascular and some body movements
Midbrain
central part of brain; neural circuits for hearing, seeing and orienting movements
Tectum
roof (above ventricle) of midbrain functions include sensory processing, visual and auditory; production of orienting movements
Tegmentum
floor (below ventricle); movement related (species specific) and pain perception
Superior and Inferior Colliculus
superior = visual input; inferior = auditory input; both function for orienting movements
Red nucleus
limb movements; hemoglobin
Substantia nigra
forebrain connection; initiating movements; reward, addiction, melanin; dopamine regulation; related to parkinson’s
Diencephalon
integrates sensory and motor information on the way to cerebral cortex; includes hypothalamus and thalamus
Hypothalamus
in the brain’s midline; involved in temperature regulation, eating, drinking and sex; connected to the pituitary gland
Thalamus
information from all senses integrated and sent out; massa intermedia (only half have)
Forebrain
involved in thinking, planning, language; contains the limbic system, basal ganglia and neocortex; newest part of brain (evolution wise)
Cerebral cortex
outer layer of neural tissue; connected to all areas of the brain
Neocortex & 2 types of neurons in it
most recently evolved outer layer; 6 layers of grey matter that construct our reality; pyramidal (long axon and multiple dendrite) vs stellate (interneurons, small, star shaped) neurons; organized incolumns
Basal ganglia
subcortical forebrain nuclei that coordinates voluntary movements of limbs and body and procedural learning; connected to the thalamus and midbrain; contains the caudate nucleus, amygdala putamen and globus pallidus
Limbic system
forebrain structure between neocortex and brainstem; controls 4 f’s feeding, fleeing, fighting and sex; contains the cingulate cortex, amygdala and the hippocampus
Olfactory system
responsible for sense of smell; olfactory bulbs in forebrain; pyriform cortex receives smell info
Cranial Nerves
12 nerve pairs that control sensory and motor functions of the head, neck and internal organs; both efferent and afferent nerves
Spinal Nerves (5)
1) Cervical
2) Thoracic
3) Lumbar
4) Sacral
5) Coccygeal
Vertebrae
bones that form the spinal column
SNS connections
neurons enter in spinal cord in posterior roots (afferent and sensory); leave through the anterior roots (efferent and motor)
Law of Bell and Magendie
sensory dorsal, motor ventral
Autonomic Nervous System (ANS)
collection of “mini brains” that control involuntary body functions; quite complex; sympathetic and parasympathetic divisions
Sympathetic division
arouses body for action, such as mediating the involuntary fight or flight response to alarm by increasing blood pressure and heart rate among other things; high efferent branching; project from lumbar and thoracic
Parasympathetic division
opposition to the sympathetic; prepares body to rest and digest by reversing the alarm and stimulating digestion; low efferent branching; project from brain and sacral
Enteric Nervous System (ENS)
located in sheets of tissue in the esophagus, stomach, small intestine and colon; controls the “gut”; quite complex (many neurons/transmitters, profusion of glial cells); connects via vagus nerve
Dorsal nerve root in spinal cord
it is sensory afferent information that is unipolar (only flows one direction)
Ventral nerve root in spinal cord
it is efferent motor information that is multipolar (flows in both directions)
Spinal cord internal structure
white matter periphery (myelinated); grey matter inside (cell bodies); CSF in central canal; lower level has more grey, higher has more white
CSF locations
1) ventricles
2) central canal (in spinal cord)
3) subarachnoid space
made in the choroid plexus of ventricles
Hydrocephalus
too much CSF in brain; tumor obstructing a channel/water build up
Blood brain barrier
semipermeable transport mechanisms; the blood vessels aren’t porous though (tightly packed); keeps molecules outside of the brain (ie. drugs); allows certain hormones in
5 Major divisions of the brain
1) Telencephalon (forebrain)
2) Diencephalon (forebrain
3) Mesencephalon (midbrain)
4) Metencephalon (hindbrain)
5) Myelencephalon (hindbrain)
Myelencephalon (1)
most posterior; aka medulla (heartrate and breathing); origin of reticular formation (arousal system)
Metencephalon (2)
contains cerebellum: fine motor skills, cognition; and Pons: reticular formation and axons to cerebellum and brain (bridge)
Mesencephalon (2)
1) Tectum (roof): two little bumps with the superior and inferior colliculi
2) Tegmentum (floor): reticular formation, red nucleus, substantia nigra, periaqueductal gray (pain control & defensive behavior; opiates act on it)
Periaqueductal gray
pain control and defensive behavior; opiates act on it; gate theory of pain
Diencephalon
contains the thalamus, hypothalamus, mammiliary bodies and optic chiasm
Telencephalon
largest division; limbic system, corpus callosum, basal ganglia, the 4 lobes, prefrontal cortex; controls sensory perception
