Chapter 8: The Nervous System Flashcards
afferent division
carries sensory information from PNS to CNS
efferent division
carries motor commands from CNS to PNS
glial cells
neuroglia; provide physical and environmental support for neurons to maintain their environment
axon hillock
cone shaped region of an axon where it joins the cell body
Nissle bodies
clusters of rough ER and free ribosomes; give gray color to “gray matter”
multipolar neuron
has two or more dendrites and a single axon; most common neurons
bipolar neuron
one dendrite, one axon with cell body directly between
Pseudounipolar neuron
The dendrites and axon are continuous and the cell body lies off to one side
Types of somatic sensory receptors
External Receptors, Proprioceptors, Visceral receptors
somatic motor neurons
innervate skeletal muscles
visceral motor neurons
innervate all peripheral affectors other than skeletal muscles
interneurons
“association neuron”; a nerve cell within the central nervous system that forms synapses with other neurons
astrocytes
-Most common
-Provide structural and metabolic support for neurons
Oligodendrocytes
Type of neuroglia, myelinate axons in the CNS
myelin
a fatty substance that helps insulate neurons and speeds the transmission of nerve impulses; provides white color to “white matter”
microglia
the smallest of glial cells; they act as phagocytes and protect the brain from invading microorganisms
ependymal cells
line cavities of the brain and spinal cord, circulate cerebrospinal fluid
satellite cells
surround neuron cell bodies in PNS (basically PNS astrocytes)
Schwann cells
myelinate axons in the PNS
neural cortex
a layer of gray matter at the surface of the brain
ascending pathways
sensory
descending pathways
motor
membrane potential
voltage across a membrane
action potential
the propagated electrical message of a neuron that travels along the axon to the presynaptic axon terminals
continuous propagation
action potential occurring along unmyelinated axons
saltatory propagation
-action potential occurring along myelinated axons
-jumping affect= faster conduction
neuroeffector junction
specialized synapse between a nerve cell and the organ or tissue it innervates
cholinergic synapse
releases acetylcholine (ACh)
adrenergic synapse
release norepinephrine (NE) neurotransmitter
release epinerphrine or adrenaline (hormone)
neuronal pool
functional groups of neurons
divergence
multiple outputs
convergence
multiple inputs
Three layers of meninges
dura mater, arachnoid mater, pia mater
dorsal roots
sensory input to cord
ventral roots
motor output from cord
6 divisions of brain
medulla oblongata, pons, midbrain, cerebellum, diencephalon, cerebrum
cerebrum
can be divided into 2 hemispheres; responsible for conscious thought
left hemisphere
controls the right side of the body; analytical, language, math, speech
right hemisphere
controls the left side of the body; creative, intuitive, spacial
Wernicke’s area
general interpretive; language/math; usually in the left hemisphere
Broca’s area
speech; left hemisphere
corpus callosum
the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
memory consolidation
conversion from short-term to long-term memory
Diencephalon
thalamus, hypothalamus, epithalamus (pineal gland)
thalamus
-the brain’s sensory switchboard (sorting center)
-located on top of the brainstem
-directs messages to the sensory receiving areas in the cortex
-transmits and replies to the cerebellum and medulla
hypothalamus
a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion
pineal gland
secretes melatonin
midbrain
visual and auditory reflexes, sleep/wake cycle, alertness
pons
connects the cerebellum to the brain stem; “bridge”; relays information
medulla oblongata
-Portion of brain stem
-Controls: heartbeat, breathing, blood pressure, and digestion
cerebellum
Balance and coordination; large motor activities
Based on sensory and previous stored movement patterns
choroid plexus
produces CSF
amygdala
-Portion of gray matter inside each hemipshpere
-Responsible for emotions
hippocampus
a neural center located in the limbic system; helps process explicit memories for storage; active in learning
reticular formation
a nerve network in the brainstem that plays an important role in controlling arousal
limbic system
neural system located below the cerebral hemispheres; associated with emotions and drives
dermatone
a specific area of the skin that receives sensory input from a pair of spinal nerves
12 cranial nerves in order
- Olfactory2. Optic3. Oculomotor4. Trochlear5. Trigeminal6. Abducens7. Facial8. Vestibulocochlear9. Glossopharyngeal10. Vagus11. Accessory12. Hypoglyssal
cervical plexus
c1-c5; innervates the muscles of the neck and the diaphragm; phrenic nerve
brachial plexus
C5-T1; innervates the shoulder girdle and upper limbs; axillary, musculocutaneous, median, radial, ulnar nerves
lumbosacral plexus
T12-s4; supply pelvic girdle and lower limbs; femoral, obturator, saphenous, gluteal, sciatic nerves
adrenal medullae
center of each adrenal gland; a modified sympathetic ganglion with a short axon; release neurotransmitters into the blood stream
neurons
basic units of the nervous system; can be separated into three groups: sensory neurons, motor neurons, and interneurons
Norepinephrine
neurotransmitter; adrenergic; produced in adrenal medullae; found in postganglionic sympathetic fibers; usually excitatory
reflex arc
“wiring” of a single reflex
cranial nerve X
vagus nerve
hydrocephalus
abnormal accumulation of CSF within the ventricles of the brain
affects of parasympathetic nervous system
increases digestion (rest and digest), decreases heartrate, has no effect on perspiration, causes pupillary constriction
alpha 1 receptor
vasoconstriction (skeletal muscle), mydriasis (pupil dilation), ejaculation
alpha 2 receptor
inhibition of presynaptic terminals–inhibits continued release of norepinephrine from the presynaptic terminal; limits adrenergic response
beta 1 receptor
increased HR, conductivity, automaticity, contractility, renin secretion increased in kidneys
beta 2 receptor
bronchodilation, vasodilation, inhibition of uterine contractions, skeletal muscle tremors
dopaminergic receptors
-Vasodilation (increased bloodflow)
-Kidneys, heart, brain
mu 1 receptor
analgesia
mu 2 receptor
constipation (decrease GI), euphoria, physical dependence, respiratory depression
delta receptors
analgesia
decreased GI function
sigma receptors
stimulate respiratory and vasomotor activity, hallucinations, dysphoria
kappa receptors
spinal analgesia, sedation, and pupillary constriction
epsilon receptors
analgesia
opiate drugs
affinity for mu and kappa receptors
pituitary gland
primary structure that links the nervous system to the endocrine system
cauda equina
“horse’s tail”, a fan of nerve fibers at the end of the spinal cord
mydriasis
dilated pupils
olfactory nerves (I)
smell
Optic Nerves (II)
vision
Oculomotor Nerves (III)
Moves eyelid and eyeball, adjusts pupil size
trochlear nerves (IV)
-superior oblique muscles of the eyes
-ability to loook down
trigeminal nerves (V)
sensory (face, mouth) and motor (mouth)
abducens nerves (VI)
lateral rectus muscle of eye
facial nerves (VII)
facial expressions, sensory facial input, control of facial glands, taste
vestibulocochlear nerves (VIII)
equilibrium, hearing
glossopharyngeal nerves (IX)
tongue/pharynx, taste, swallowing, saliva
vagus nerves (X)
sensory: pharynx, external acoustic canal, visceral organs motor: visceral organs, cardiac muscle, smooth muscle, GI glands
accessory nerves (XI)
innervate neck and back, specifically sternocleidomastoid and trapezius muscles
hypoglossal nerves (XII)
tongue
elevated ridges on brain
gyri
shallow depressions in brain
sulci
Ganglion
group of nerve cell bodies in the PNS
Functional groups of neurons
Sensory, motor, interneuron neurons
