Studied by 44 people
Development of the Nervous System
begins as a tube along the axis of the body
folds over during development and is hollow as a result
starts as 3 swellings after 4 weeks in the uterus (turns into 5)
neural tube becomes the spinal cord
Rhombencephalon
Hindbrain
Mesencephalon
Midbrain
Prosencephalon
Forebrain
spina bifida
when the neural tube doesn't completely close at the caudal end
Central Nervous System
brain
spinal cord
Peripheral Nervous System
neural tissue outside of the CNS
sensory and motor neurons
Sensory Nervous System
contains receptors that transmit information to the CNS
Motor Nervous System
transmits information for the CNS to the rest of the body
sends motor information to effectors
Somatic Sensory
apart of the sensory nervous system
voluntary actions
Visceral Sensory
apart of the sensory nervous system
involuntary actions
Somatic Motor
apart of the motor nervous system
voluntary actions
Autonomic Motor
apart of the motor nervous system
involuntary actions
Gray Matter
consists of neural and glial cell bodies
outer portion of the brain
inner portion of the spinal cord
White Matter
consists of axons
inner portion of the brain
outer portion of the spinal cord
Nerves
cable like bundle of parallel axons
surrounded by three layers of connective tissue
Endoneurium
delicate connective tissue around individual axons in nerve
Perineurium
the sheath of connective tissue that covers a bundle of nerve fibers (fascicles)
Epineurium
connective tissue surrounding the entire nerve
Synapse
junction between two neurons that is responsible for unidirectional transmission of nerve impulses
can make contact with cell bodies, dendrites or other axons
release neurotransmitters
Excitatory
type of synapse
activity promotes impulses
depolarizes the next cell membrane
Inhibitory
type of synapse
inhibits impulse transmission
hyperpolarizes next cell membrane
Acetylcholine
neurotransmitter that is released at all neuromuscular junctions
Multipolar Neuron
has several dendrites
one axon
majority of the neurons in the CNS
Unipolar Neuron
one long axon with dendrites at the end
touch and stretching
Bipolar Neurons
one dendrite and one axon
makes up many sensory nerves
Pyramid Neuron
type of multipolar neuron
triangular shaped bodies
found in the cerebral cortex, hippocampus and amygdala
linked to cognitive ability
Neuroglia
glial cells
CNS and PNS
physically protect and nourish the neuron
higher amount compared to the amount of neurons
Oligodendrocytes
CNS axons only
extensions of cytoplasm that wrap around the axon
produce myelin to insulate the electrical activity and produce rapid nerve impulses
Schwann Cells
PNS only
whole cell that wraps around an axon
insulate electrical activity by myelinating the axons for rapid nerve impulses
Astrocytes
most common glial cell
regulation of the environment around axons and synapses
repairs damage of neurons
Microglia
type of macrophage associated with the immune system
clean-up cell
Multiple Sclerosis
results from the destruction of the myelin sheath and axons
Meninges
three layers of connective tissue that surround the spinal cord and brain
protection
Pia Mater
innermost layer of meninges
adheres to surfaces
highly vascular
Arachnoid Mater
middle layer of meninges
weblike and avascular
Dura Mater
outer layer of meninges
dense, irregular connective tissue
2 layers in the brain
Epidural Space
area between the vertebral column/cranium and dura mater
blood vessels, fat and connective tissue
Subdural Space
area between the arachnoid and dura mater
contains interstitial fluid
Subarachnoid Space
area between the pia and arachnoid mater
contains cerebralspinal fluid
Severe Head Trauma Cases
can create bleeding between the meninges
cause pressure that can destroy neurons and glia cells
Epidural Block
regional anesthesia that numbs the lower body
Spinal Tap
needle inserted between the lumbar vertebrae into subarachnoid space
withdraws cerebrospinal fluid and can introduce substances
Cerebrospinal Fluid
produced in the choroid plexuses of each of the four brain ventricles
found in the subarachnoid space of the brain and spinal cord
protection of the brain; brain floats in it and provides cushioning
transports nutrients and removes wastes
Hydrocephalus
cerebrospinal fluid accumulates in the brain ventricles
babies heads with swell
Blood-Brain Barrier
barrier that strictly regulates which substances can enter the interstitial fluid in the brain
capillaries in the brain are selectively permeable
glial cells surround the capillaries to catch things that get through the barrier
Bone
most important physical defense for the CNS
not applicable for the PNS
Spinal Cord
pathway for sensory and motor impulses to and from the brain
responsible for the quickest reflex reactions to a stimulus
External Spinal Cord Anatomy
from medulla oblongata to second lumbar vertebra
cervical enlargement consists of nerves from the upper limbs
lumbosacral enlargement consists of nerves from the lower limbs
Internal Spinal Cord Anatomy
grey matter consisting of unmyelinated axons and glial cells, butterfly shape
white matter consisting of myelinated axons
Anterior Horns
grey matter in spinal cord
contain cell bodies of somatic motor neurons which innervate skeletal muscle
Posterior Horns
grey matter in spinal cord
contain axons of sensory neurons
cell bodies of interneurons
Lateral Horn
grey matter in spinal cord
found in T1-L2
cell bodies of autonomic motor neurons
innervate cardiac and smooth muscle and glands
Grey Commissure
grey matter in spinal cord
unmyelinated axons
communication route between the right and left side
Spinal Nerves
make up PNS
connect the CNS to sensory receptors, muscles and glands
Meningeal Branch
branch of spinal nerves
returns through vertebral foramen to innervate meninges, vertebrae and ligaments
Rami Communications
two branches in the spinal nerves that function within the autonomic nervous system
Dorsal Ramus
branch of spinal nerves
innervate deep muscles and skin of the back
Ventral Ramus
branch of spinal nerves
innervate superficial back muscles, lateral and ventral muscles and skins and muscles of upper and lower limbs
do not go directly to body structures and form networks on both sides of the body
Cervical Plexus
portion of anterior rami of the C1-C4 and part of C5
positioned laterally
head, neck, upper shoulders and chest
Phrenic Nerve
C3-C5
innervate the diaphragm
Brachial Plexus
positioned lateral from C5-T1
extends downward under the clavicle into axilla
part of shoulders and all upper limbs
5 major nerves
Axillary Nerve
from brachial plexus
sensory from skin of shoulder
motion to some shoulder muscles
Musculocutaneous Nerve
from brachial plexus
flexors of the arm
Radial Nerve
from brachial plexus
extensors of the arm and forearm
Median Nerve
from brachial plexus
anterior forearm and portion of the hand
Ulnar Nerve
from brachial plexus
anterior/medial forearm and majority of the hand
Lumbar Plexus
side of anterior rami of L1-L4
anterolateral abdominal walls, external genitals and parts of lower limbs
2 major nerves
Femoral Nerve
from lumbar plexus
anterior muscles of the thigh
Obturator Nerve
from lumbar plexus
medial (adductor) muscles of the thigh
Sacral Plexus
immediately caudal to lumbar plexus
formed by L4-S5
lower back, pelvis, posterior thigh, parts of the foot
one main nerve
Sciatic Nerves
largest nerve extending the length of each leg
irritation can cause crippling pain and discomfort, pinching of the nerve (sciatica), arthritic inflammation, bulging disk, vitamin deficiencies
Dermatomes
area of skin supplied by a single spinal nerve (all but C1 innervate single portion)
Reflexes
rapide involuntary reactions to a stimulus
required to initiate a response
few neurons must be involved and synaptic delay must be minimal
occurs the same way everytime
Reflex Arc
stimulus
sensory neuron activated
processed in the CNS
motor neuron activated
response by effector
Telencephalon
the anterior division of the forebrain consisting of the cerebrum
Diencephalon
the posterior division of the forebrain consisting of the thalamus, epithalamus and hypothalamus
Mesencephalon
midbrain
Metencephalon
the part of the hindbrain that develops into the pons and the cerebellum
Myelencephalon
the posterior part of the hindbrain that forms the medulla oblongata
Medulla Oblongata
last portion of the brain before the spinal cord
contains sensory and motor tracts to and from the brain
controls heart rate and breathing
vomiting, coughing and sneezing reflexes
Pons
contains sensory and motor tracts that connect the brain and spinal cord (bridge)
helps to regulate the breathing rate
involved in sound localization
Cerebellum
second largest part of the brain
highly convoluted surfaced covered in folds
coordinates and fine tunes skeletal muscle movement
monitors position of joints and muscles
Midbrain
between pons and diencephalon
controls various sub or unconscious movement of the eye
contains elements of the auditory pathway
Diencephalon
contains the thalamus, epithalamus and hypothalamus
surrounds the third ventricle
Thalamus
paired oval masses of grey matter, each consisting of a dozen thalamic nuclei
division of the diencephalon
all sensory signals pass through here (excluding smell)
Hypothalamus
division of the diencephalon
involved in hormone production
regulation of emotions, eating, drinking and body temperature
Epithalamus
connects the limbic system to the rest of the brain
division of the diencephalon
main component is the pineal gland
important for sleep regulation
Cerebrum
location of conscious thought processes and the origin of intellectual functions
formed from the telencephalon
surface folds into elevated ridges
Gyri
adjacent gyri are separated by shallow grooves (sulci) or deeper grooves (fissures)
Cerebral Hemispheres
2 components of the cerebrum
divided by a longitudinal fissure extends along the midsagittal plane
memory and consciousness can not be assigned to particular regions
Corpus Callosum
main tract connecting the right and left cerebral hemispheres
Olfactory Nerve
cranial nerve that carries impulses to the brain from the olfactory epithelium
(I)
sensory only
only type of nervous tissue to regenerate
anosmia is partial or total loss of smell
Optic Nerve
(II) cranial nerve that carries impulses from the retina
sensory only
left and right optic nerves unite at optic chiasma
information passes through thalamus on way to occipital lobe of cerebrum
anopsia is visual defects
Oculomotor Nerve
(III) cranial nerve that controls pupil size
motor fibers to four extrinsic eye muscles and upper eyelid
sensory fibers from proprioceptors
damage causes upper eyelid droop, paralysis of eye muscles, double vision or difficulty focusing
Trochlear Nerve
(IV) cranial nerve
motor fibers to the fifth eye muscle
sensory fibers from proprioceptors
damage can cause paralysis of superior oblique muscle leading to visual issues
Trigeminal Nerve
(V) cranial nerve
motor fibers innervate muscles of mastication
motor sensory fibers from the face
divides into three branches
Ophthalmic Branch
part of the trigeminal nerve
motor fibers to tear gland
sensory fibers from cornea, nose, forehead and anterior scalp
Maxillary Branch
part of the trigeminal nerve
sensory fibers from nasal mucosa, gums and cheek
Mandibular Branch
part of the trigeminal nerve
sensory fibers from the lower jaw and teeth and part of the tongue
motor fibers to the temporalis, masseter and pterygoid muscles
damage causes trigeminal neuralgia (inflammation of sensory components)
Note
Flashcard