U7 CNS & PNS Flashcards
Meninges & Their Layers
membranes located between bone and soft tissues
(dura mater, arachnoid, pia mater)
Cerebrospinal Fluid (CSF)
clear liquid that bathes the brain & spinal cord; cushions the brain and serves as a shock absorber; produced by the choroid plexus within each of the 4 ventricles; tight junctions within choroid plexus form a blood-CSF barrier that keeps brain secure
Subdural Hematoma
associated with TBI; bleeding within the brain, puts pressure on the brain and can be life threatening
Spinal Cord
passes down the vertebral canal; C1-C8, T1-T12, L1-L5
3 Major Parts of the Brain
- Cerebrum
- Brain Stem
- Cerebellum
Cerebrum
wrinkly large part of the brain (cerebral cortex = outer layer) // higher mental function, solving problems
Cerebellum
balance and coordination, modulates voluntary movement of the limbs; white matter within the cerebellum gives it a tree-like appearance (arbor vitae)
Brain Stem
regulates visceral functions (AUTONOMIC SYSTEM)
Corpus Callosum
connects the 2 hemispheres; left and right cerebral hemispheres are separated by the corpus callosum
Brain Convolutions
wrinkles and grooves of the cerebrum; fissures = deep groove, sulcus = shallow groove, gyrus = bump
Lobes
- Frontal = executive functions
- Parietal = perception, sense-making, math
- Occipital = vision
- Temporal = memory, language, auditory
Longitudinal Fissure
separates the brain into 2 hemispheres
Transverse Fissure
separates cerebrum and cerebellum
Ventricle
fluid filled cavities, contains CSF; 4 total (2 lateral ventricles, interventricular foramen connects lateral to third ventricle, & cerebral aqueduct connects third ventricle to fourth ventricle)
Association Areas
for interpreting and analyzing information:
- Frontal = prefrontal association area, motor association area, primary motor cortex
- Parietal = sensory association area, primary somatic-sensory cortex
- Occipital = visual association area, visual cortex
- Temporal = auditory association area, auditory cortex
Diencephalon
- Hypothalamus: hormones, heart rate, blood pressure, body temp, hunger, attaches to pituitary (HOMEOSTASIS & ANS)
- Thalamus: relay station (all info. minus smell is processed through thalamus)
Optic Tract/Chiasma
optic nerves cross over each other; left side of the brain controls the right side of the body (vice versa)
Midbrain (Mesencephalon)
connects the hindbrain to the forebrain; visual reflexes, eye movements
Pons
relay sensory information; links brain to spinal cord; in charge of unconscious movements and processes (e.g. sleep, posture, respiration, swallowing, bladder control); signals from the cerebrum to the cerebellum pass through here; PART OF BRAIN STEM
Medulla Oblongata
heart, respiration, blood pressure; controls coughing, sneezing, hiccuping, sweating, vomiting, etc.; PART OF BRAIN STEM
Pituitary Gland
“master gland”; controls hormones
Hippocampus
storage and retrieval of memories
Amygdala
storage of memories associated with emotion (fear response and aggression)
Limbic System
hypothalamus, hippocampus, amygdala = all have a role in emotions
Central Sulcus
shallow groove separating the frontal lobe from the parietal lobe
Lateral Fissure
deep groove separating the frontal and parietal lobe from the temporal lobe
Gray vs. White Matter
white = myelinated nerve fibers (inside of the brain), gray = non-myelinated soma & dendrites (outside of the brain)
Epidural Space
between the skull/vertebrae and dura mater
Subdural Space
separation between the dura and arachnoid meninx
Subarachnoid Space
separation between arachnoid and pia mater meninx
Blood Supply & the Blood-Brain Barrier
CNS is protected by a blood-brain barrier that regulates substances entering the brain – tight junctions within capillaries and astrocytes comprise this barrier (absent in areas of the brain that monitor pH, blood glucose, etc.)
Hydrocephalus
“water on the brain”; results from blockage of the route of CSF and its absorption
Spinal Cord
begins at the foramen magnum and ends at the first lumbar vertebra (cervical, thoracic, lumbar, and sacral regions) – 31 pairs of spinal nerves
Cervical & Lumbar Enlargements
supply the upper limbs (cervical) and lower limbs (lumbar)
Conus Medullaris
terminal end of the spinal cord (typically around L1 vertebral level in avg. adult)
Cauda Equina
nerve bundles at the bottom of the spinal cord; connects to other parts of the body and allows ability to move and feel sensation in the legs & bladder
Autonomic vs. Somatic
somatic = things you can consciously sense and do, autonomic = works without thinking about it
Spinal Cord’s Fissures…
anterior median fissure & posterior median sulcus
Spinal Cord Anatomy (think “horns”)
consists of a central area of gray matter; 2 dorsal/posterior “horns” & 2 ventral/anterior “horns”; posterior = SENSORY, anterior = MOTOR
Spinal Tracts
- Ascending = carry SENSORY info up the spinal cord
- Descending = carry MOTOR info down the spinal cord
- Tracts are WHITE matter (not GRAY)
Decussation
“crossover” = left/right, right/left (many fibers exhibit decussation
Hindbrain
medulla oblongata + pons + cerebellum
Tectum
a part of the midbrain/mesencephalon – consist of 4 nuclei called corpora quadrigemina (visual attention, tracking objects, visual reflexes)
Reticular Formation
a group of 100 nuclei scattered throughout the medulla, midbrain, and pons that function in somatic motor control, autonomic control, arousal, and pain modulation
Epithalamus (Diencephalon)
contains the pineal gland; cone - shaped gland, best known for synthesis of
melatonin from serotonin;
role in light-sensitive Circadian rhythms
Cerebrum Basal Nuclei
masses of gray matter buried deep in the cerebral hemispheres; involved in motor control and thought process
Brain Waves
rhythmic voltage changes resulting from
synchronized postsynaptic potentials in the cerebral cortex (recorded on an EEG)
Sleep
controlled by the hypothalamus and brain stem; 4 stages, 4th = REM; temporary state of unconsciousness
Motor Control
voluntary muscle contractions are initiated in the
motor association (premotor) area of the frontal lobes; the impulse is then sent to the pre- central gyrus (primary motor area)
Somatic Control
the post-central gyrus functions as the primary sensory area or somesthetic; here neurons receive sensory information.
Cerebral Lateralization
the assignment of different tasks to different hemispheres (aka handedness)
Parasympathetic NS vs. Sympathetic NS
parasympathetic = “rest and digest” – sympathetic = “fight or flight”
