central nervous system
consists of the brain and spinal cord
peripheral nervous system
consists of motor neurons and sensory neurons leading to and from the spinal cord
brain
receives and processes sensory information, initiates responses, stores memories, generates thoughts and emotions
spinal cord
conducts signals to and from the brain, controls reflexes and activities
motor neurons
CNS to muscles to glands (efferent)
sensory neurons
sensory organs to CNS (afferent)
somatic nervous system
division of the peripheral nervous system that controls voluntary movements
autonomic nervous system
division of the peripheral nervous system that controls involuntary responses
sympathetic nervous system
division of the autonomic nervous system that prepares the body for emergencies - fight or fligh
parasympathetic nervous system
division of the autonomic nervous system that promotes normal functioning - rest and digest
functioning of the nervous system
Relay Information - sensory system, sensory neurons
interpret/make decisions - association system, interneurons
carry out some action - motor system, motor neurons
protection of the CNS
bone - skull and vertebral column
meninges - 3 layers
ventricular system
cerebrospinal fluid
blood-brain barrier
meninges
set of thin membranes that hold the brain and spinal cord in place and act as a protective buffer
dura mater
meninges layer - tough outer layer of fibrous tissue
arachnoid layer
meninges layer - like a spider web; thin sheet of delicate connective tissue (CSF below it)
pia mater
innermost meninge layer - moderately tough inner layer that clings to the brains surface (CSF above it)
ventricular system
responsible for circulating CSF throughout the CNS
1
lateral ventricles
2
interventricular foramen
3
third ventricle
4
cerebral aqueduct
5
fourth ventricle
6
central canal
where CSF is found
central canal of spinal cord
cerebral aqueduct of periaqueductal gray
ventricles (lateral, third, fourth)
subarachnoid space of meninges
roles of CSF
provides a medium through which nutrients, hormones, etc, get access to brain cells; dispose of waste products
protects brain and spinal cord by acting as a buffer (liquid buffer or cushion to absorb internal as well as external forces)
blood brain barrier
protection of brain from blood born substances
neuraxis
an imaginary line that is drawn through the center of the length of the CNS, from the bottom of the spinal cord to the front of the forebrain
coronal section
cut in the ventricle plane, from the crown of the head down, yielding a frontal view of the brain's internal structures
horizontal section
usually viewed looking down on the brain from above - a dorsal view
sagittal section
cut lengthwise from front to back and viewed from the side - medial view
white matter
nervous tissue of the CNS consisting of neurons and their myelin sheaths
grey matter
nervous tissue containing cell bodies as well as fibers; forms the cerebral cortex consisting of unmyelinated neurons
contralateral
on or relating to the opposite side
ipsilateral
on or relating to the same side
medial
toward the midline
lateral
away from the midline
afferent
towards point of reference (CNS)
efferent
away from point of reference (CNS)
nucleus
collection of cell bodies in the CNS
ganglion
collection of cell bodies in the PNS
tract
collection of axons running together from point A to point B in the CNS
nerve
collection of axons running together from point A to point B in the PNS
frontal lobe
lobe involved in executive functions, thinking, planning, organisation, problem-solving, emotions, behaviour control and personality
parietal lobe
lobe involved in perception, making sense of the world, arithmetic, and spelling
motor cortex
involved in movement, part of the frontal lobe
sensory cortex
involved in sensations, part of the parietal lobe
occipital lobe
lobe involved in vision
temporal lobe
lobe involved in memory, understanding, and language
3 major divisions of the brain
forebrain
midbrain
hindbrain
ventricles in the forebrain
Lateral
Third
subdivisions of the forebrain
telencephalon (lateral ventricle)
diencephalon (third ventricle)
ventricle in the midbrain
cerebral aqueduct
subdivision of the midbrain
mesencephalon
ventricle in the hindbrain
fourth
subdivisions of the hindbrain
metencephalon
myelencephalon
principles structures of the forebrain
cerebral cortex
basal ganglia
limbic system (lateral/telencephalon)
thalamus
hypothalamus (third/diencephalon)
principle structures of the midbrain
tectum
tegmentum (cerebral aqueduct/mesencephalon)
principle structures of the hindbrain
cerebellum
pons (fourth/metencephalon)
medulla oblongata (myelencephalon)
gyri
hills of the cortex
sulci
grooves of the cortex
fissure
especially large, prominent sulcus
central sulcus
divides frontal/parietal lobes
lateral fissure
divides temporal love and parietal/frontal lobes
precentral gyrus
primary motor cortex
postcentral gyrus
primary somatosensory cortex
corpus callosum
large band of axons that connects corresponding part of association of the left and right hemispheres
basal ganglia
-major parts include the caudate nucleus, putamen, and globus pallidus -consits of a variety of subcortical cell groups engaged primarily in motor control, motor learning, executive functions, behaviour, and emotions -degredation of neurons in this area causes Parkinsonsl
limbic system
involves many different brain areas and structures that all work together to play a role in out emotions and memory such as the hippocampus and amygdala
hippocampus
small organ wihich regulates emotion, associates w long term memory
amygdala
one of two almond shaped groups of nuclei located deep w/in the lobes of the brain, integrative centre for emotions, emotional behaviour, and motivation
structures of the diencephalon
thalamus + hypothalamus
thalamus
-relays info from sensory receptors to proper brain areas to be processed -regulation of consciousness, sleep, alertness
hypothalamus
-organizes behaviour related to the survival of the speices
controls autonomic NS and endocrine system (secretions from the anterior pituitary gland) -posterior pituitary could be considered an extension of it
structures of the mesencephalon
tectum + tegmentum
tectum
Consists of: -superior colliculi - located at top-role invisual system -inferior colliculi - located below superior colliculi, role in auditory system
tegmentum
includes: -rostal end of the reticular formation (states of consciousness like alertness and sleep) -several nuclei controlling eye movement -periaqueductal gray matter (primary control centre for descending pain modulation) -red nucleus (motor coordination) -substantia nigra (reward and movement) -ventral tegmental area (sends dopaminergic projections to both the limbic and cortical areas)
structures of the metencephalon
cerebellum and pons
cerebellum
-receives info from the sensory systems, spinal cord, other parts of the brain and then regulates motor movements -coordinates voluntary movements such as posture, balance, coordination, speech -- resulting in smmoth + balanced muscular activity
pons
-large bulge in the brain stem, lies between the midbrain and medulla, immediately ventral to the cerebellum -contains a portion of the reticular formation -contains a large nucleus that relays information from the cerebral cortex to the cerebellum -as part of the brain stem it also impacts several automatic functions (breathing/necessary for life)s
structures of the myelencephalon
medulla oblongata
medulla oblongata
the most caudal portion of the brain stem; its lower border is the rostal end of the spinal cord -contains numerous nuclei that act as control centers for the autonomic nervous system (vital functions are controlled -breathing, heat rate, temp - damage usually means rapid deaths
spinal cord
-long, conical structure (about as thick as an adult's little finger) -principle function is to distribute motor fibres to the effector organs of the body (glands/muscles) and to collect somatosensory info to be passed on to the brain -has a certain degree of autonomy from the brain; various reflexive control circuits are located there
spinal nerves
31 pairs
8 cervical (C1-C8)
12 thoracic (T1-T12)
5 lumbar (L1-L5)
5 sacral (S1-S5)
1 coccygeal nerve (Co1)
peripheral nervous system
cranial and spinal nervess
somatic nervous system
comprised of -sensory neurons conveying information form the somatic receptors in head, body wall and limbs and from receptors of special senses -motor neurons that conduct impulses from CNS to skeletal muscles
autonomic nervous system
consists of -sensory neurons that convey information from the autonomic sensory receptors (located primarily in visceral organs) to CNS
motor neurons that conduct impulses from CNS to smooth muscle, cardiac muscle and glands
two main functional divisions (parasympathetic/sympathetic) most organs receive inout from both, but systems are antagonistic (produce opposite effects)
sympathetic nervous system
division of the autonomic nervous system: fight or flight response (emergency functioning)p
parasympathetic nervous system
division of the autonomic nervous system which supports activities involved w increase in body's supply or stored energy (salivation, digestion, increased blood flow to gastrointestinal system) -promotes normal functioning "rest and digest"
autonomic pathway
consists of two neurons that synapse in an autonomic ganglion
preganglionic neuron from CNS to autonomin ganglion, postganglionic neuron from autonomic ganglion to target tissue
parasympathetic pathway
preganglionic neuron: soma is usually in the brain stem or sacral (bottom of spinal cord) -releases acetylcholine postganglionic neuron: soma is usually in a ganglion near the target organ -realses NT acetylcholine or nitric oxide activates: rest and digest (craniosacral -> long pre-gang axon -> short post gang axon)
sympathetic pathway
preganglionic neuron: soma usually in spine
NT acetylcholine released post ganglionic neuron: soma in a sympathetic ganglion located next to the spinal cord
NT released: norepinephrine activates: fight or flight (thoracicolumbar -> short pre gang axon -> long post gang axon)