Study Guide Flashcards
Central Nervous System (CNS)
consists of the brain and spinal cord
PNS (peripheral nervous system)
consists of the nerves and ganglia outside of the brain and spinal cord
nerves
organs that contain bundles of nerve fivers (axons) that carry information to and from the CNS
ganglia
Collections of nerve cell bodies that lie outside the CNS
parts of a typical neuron
cell body, dendrites, axon
cell body (soma)
contains the nucleus and other parts of the cell needed to sustain its life
dendrites
primary site for receiving signals from other neurons
axon
sends signals: they branch at the distal end and each branch ends in a synaptic knob which forms a junction with another cell
Features of Neurons
excitability, conductivity, secretion
secretion
a neurotransmitter is secreted when an electrical signal reaches the end of a nerve fiber that passes a message to other cells
Excitabilty (Irritability)
can respond to environmental changes called stimuli
conductivity
neurons respond to stimuli by producing electrical signals
afferent neurons
Nerve cells that carry impulses towards the central nervous system
efferent neurons
Nerve cells that conduct impulses away from the central nervous system
what are the four kinds of neuroglia found in the CNS
oligodentrocytes, ependymal cells, microglia, astrocytes
Oligodendrocytes
Form myelin sheath in CNS and wrap around nerve fibers and insulate them from extracellular fluid, speeding up signal conduction
ependymal cells
produce and circulate cerebrospinal fluid and fills the spaces, they resemble cuboidal cells and line internal cavities of the brain and spinal cord
Microglia
small macrophages that derive from white blood cells; wander through CNS and phagocytize organisms
Astrocytes
most abundant CNS neuroglia; provide support and nourishment through a variety of functions: Structural support, blood brain-barrier, etc..
The two kind of neuroglia found in the PNS
Schwann cells and satellite cells
Schwann cells
produce myelin in PNS and assist in regeneration of damaged nerve fibers in the PNS
satellite cells
surround neuron cell bodies in PNS and regulate the chemical environment; provide support and nourishment
The automatic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). carries signals to glands, cardiac muscle and smooth muscle
ANS effectors
glands, cardiac muscle, and smooth muscle; ANS is not required for this activity but modulates it
sympathetic division of ANS
fight or flight and prepares the body to put out energy; speeds up heart, increase blood pressure, dilates pupils, makes more glucose available
parasympathetic nervous system of ANS
rest and digest, slows down heart rate, decrease blood pressure etc..
upper motor neurons
begins with soma in the cerebral cortex and has an axon that terminates on a lower motor neuron brain and spinal cord
lower motor neurons
axons leave the CNS, extend through PNS to skeletal muscles. (aka effector)
Three layers of connective tissue of a nerve
perineurium, endoneurium, epineurium
perineurium
surrounds nerve fascicles
Endoneurium
loose connective tissue that encloses axons and their myelin sheaths
epineurium
Dense connective tissue that surrounds entire nerve including fascicles and blood vessels.
neurosoma
control center of the neuron
Nissl bodies
RER in neurons – synthesize enzymes (e.g., ChAT) and peptide neurotransmitters.
Dendrites
Branchlike parts of a neuron that are specialized to receive information.
axon
sends messages to other neurons
three meninges associated with spinal cord
dura mater, arachnoid mater, pia mater
dura mater
thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord
arachnoid mater
weblike middle layer of the three meninges
pia mater
thin, delicate inner membrane of the meninges that follows the contours of the spinal cord
what part of the nervous system controls movement of hands
- somatic
- Brachial plexus
what is found in the central canal of the spinal cord
remnant of lumen of the embryonic neural tube; collapsed in most areas of the adult spinal cord but in some places it remains open and is line with ependymal cells and filled with cerebrospinal vluid
first order neuron
detects a stimulus and transmits a signal to the spinal cord or brainstem
second order neurons
continues to the thalamus at the upper end of the brainstem
third order neurons
carries the signal the rest of the way to the sensory region of the cerebral cortex; level of consciousness
Decussation
The anatomical crossing over of neurons from left to right
reflex
a simple, automatic response to a sensory stimulus, such as the knee-jerk response
four properties of a reflex
require stimulation, quick, involuntary, stereotyped
properities of reflex: require stimulation
not spontaneous actions, but responses to sensory input
properities of reflex: quick
involve few if any interneurons and minimal synaptic delay
propeties of reflex: involuntary
done without will or conscious control; difficult to suppress
properities of reflex: sterotyped
occur essentially the same way every time
visceral reflex
unconscious, automatic, stereotyped responses to stimulation involving visceral receptors and effectors; controlled by the ANS
somatic reflex
activation of skeletal muscles; controlled by somatic nervous system
components of a reflex arc
- somatic receptor
- afferent nerve fibers/sensory neurons
- integration center
- efferent nerve fibers
- effector/skeletal muscles
somatoc receptors
Sensory receptors in the skin, muscle, and tendons
afferent nerve fibers
axons that carry information into the posterior horn of the spinal cord
integrating center
a neural pool in the gray matter of the spinal cord or brainstem; has 1 or more interneuron and determines wether the efferent neuron issues a signal to the muscle
efferent nerve fibers
carry motor impulses to skeletal muscle
skeletal muscle
somatic effectors that carry out the response
5 plexus of spinal nerves
cervical, brachial, lumbar, sacral, and coccygeal plexus
cervical plexus
located in neck; nerves C1-C5; gives rise to phrenic nerves which supply the diaphragm and play an essential role in breathing
brachial plexus
located in shoulder; C5-C8, T1; important nerves are the radial and musculocutaneous nerve
lumbar plexus
located in lower back; L1-L4 with some fibers from T12; includes femoral nerve- supplies quadriceps femoris, sartorius and muscles of skin of thigh
scaral plexus
located below the lumbar; L4-S4; gives off the sciatic nerve
coccygeal plexus
located in the lower sacrum and coccyx; S4, S5, and Co1
medulla oblongata
develops from myelencephalon
location: extends from foramen magnum to pons
Anatomical features: contain anterior surface bulges called pyramids(medial) and olives(lateral)
function: regulates several basic physiological functions; cardiac center, two respiratory centers, associated with gagging and vomiting
pons
develops from metencephalon
location: a bulge anterior to the medulla oblongata
Function: sleep, and bladder control also involved in facial sensation and expression
midbrain
develops from mesencephalon
location: short segment of brainstem that connects hindbrain and forebrain (runs between cerebrum and brainstem)
includes: cerebral aqueduct, tectum, tegmentum
substantia nigra
located within midbrain
function: relays inhibitory signals to the thalamus and basal nuclei of cerebrum, improves motor performance by suppressing unwanted motor contractions, degeneration can lead to parkinsons disease
limbic system
ring of structures on the medial side of each cerebral that plays a role in learning and emotional behavior,
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
special senses
vision, hearing, taste, smell, equilibrium
vision
signals received by the primary visual cortex in the occipital lobe
hearing
signals received by primary auditory cortex in the temporal lobe in the nearby insula
equilibrium
signals from the inner ear for balance
taste
gustatory signals recieved by the primary gustatory cortex in the parietal lobe
smell
primary olfactory cortex lies in the temporal and frontal lobes
postcentral gyrus
primary somatosensory cortex; senses are distributed over the body
location: parietal lobe
Wernicke’s area
controls language reception - a brain area involved in language comprehension and expression; usually in the left temporal lobe
Broca’s area
Controls language expression - an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech.
corpus callosum
the large band of neural fibers connecting the two brain hemispheres and carrying messages between them
thalamus
the brain’s sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla
hypothalamus
A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.
amygdala
creates emotions and memories
hippocampus
critical to the creation/consolidation of long-term declarative memories; declarative memories- retention of facts you can put into words (names, dates)
what contributes to the blood-brain barrier
physical connection of astrocytes and blood vessels
somatic motor system
sends voluntary signals to skeletal muscles
autonomic nervous system
the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart).
preganglionic neuron
in the autonomic nervous system of the PNS, a neuron that has its cell body located in the CNS and whose axon extends into the PNS to synapse with a second neuron at an autonomic ganglion (the second neuron’s axon synapses with the target organ)
postganglionic neuron
in the autonomic division of the PNS, a neuron that has its cell body located in an autonomic ganglion (where a pre-ganglionic neuron synapses with it) and whose axon synapses with the target organ
adrenal medulla
secretes epinephrine and norepinephrine and is the inner core of the adrenal glands
the five primary taste sensations
sweet, sour, salty, bitter, umami
difference between taste and flavor
taste: mixture of the five primary taste sensations
flavor: mixture of the fie primary taste sensations as well as texture, smell and state of mind
which nerve endings are found in the skin
- tactile (merkel) discs- receptors for light touch and pressure
- hair receptors (peritrichial endings)- monitor movements of hair
- tactile (meissner) corpuscles- receptors fo light touch, texture, and low frequency vibrations
- ruffini corpuscles: constant, heavy pressure
- lamellated (pacinian) corpuscles- deep pressure, stretch, and high-frequency vibration
muscles for upward and doward movement of the eye
superior rectus- moves gaze up
inferior rectus- moves gaze down
orbit
the bony socket that holds the eyeball
accessories of the orbit
eyebrow, eyelids, conjunctiva, lacrimal apparatus, extrinsic eye muscles
eyebrows
keep sweat out of eyes and enhance facial expression
eyelids
moisten eye with tears, sweep debris from surface, block foreign object and block light
conjuctiva
mucous membrane that lines the eyelids and outer surface of the eyeball; keeps eye from drying
lacrimal apparatus
consists of the lacrimal gland and a number of ducts that drain the lacrimal secretions into the nasal cavity
extrinsic eye muscles
Six muscles attach to the outer surface of the eye and produce eye movements
rods
retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond; each disc is studded with a visual pigment called rhodopsin (monochromic vision)
cones
retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.; the pigments found in them are photopsins and respon to wavelength
cochela
a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses winds around the modiolus
cochlear duct
a fluid filled cavity within the cochlea that vibrates when sound waves strike it “organ of hearing”
spiral duct
organ of corti is within the cochlear duct and generates auditory nerve signals; has 4 rows of hair cells 1 row of inner and 3 rows of outer
inner hair cells
responsible for hearing which supply 90-95% of the sensory fibers of the cochlear nerve
outer hair cells
function to adjust the response of the cochlea to different frequencies and enable the inner hair cells to work with greater precision
scala vestibuli
chamber above the vestibular membrane; the upper bony passage of the cochlea; contains perilymph
scala tympani
chamber below basilar membrane; contains perilymph
static equilibrium
A condition where there are no net external forces acting upon a particle or rigid body and the body remains at rest or continues at a constant velocity.
dynamic equilibrium
perception of motion or acceleration
linear acceleration
the rate of change in linear velocity (straight line)
angular acceleration
change in rate of rotation
what is responsible for detecting linear acceleration and static equilibrium
saccule and utricle
what is responsible for the detection of angular acceleration
semicircular ducts
neural components of the eye
retina and optic nerve
retina
the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information
optic nerve
the nerve that carries neural impulses from the eye to the brain
what is the inside rear of the eyeball called
fundus
macula lutea
patch of cells on visual axis of eye (retina)
fovea centralis
tiny pit or depression in the retina that is the region of clearest vision
referred pain
pain that feels as if it is coming from some part of the body other than the part being stimulated
example of referred pain
left arm pain during a heart attack
