nervous system Flashcards
the nervous system is divided into
central nervous system and peripheral nervous system
what makes up the CNS
brain and spinal cord
does the CNS or PNS further divide?
PNS
PNS divides into what two sections?
Sensory (afferent) and motor (efferent)
sensory (afferent)
sends impulses from the senses to the CNS
motor (efferent)
sends impulses from the CNS to the muscles and glands
is afferent or efferent further divided into two more sections? and what are these two sections called?
efferent; autonomic nervous system and somatic nervous system
autonomic nervous system
involuntary muscle control
somatic nervous system
voluntary muscle control
is the autonomic NS or the somatic NS divided into two more sections? and what are these two sections called?
autonomic; sympathetic and parasympathetic
sympathetic
used in emergency situations (fight or flight)
parasympathetic
reduces sympathetic response and provides resting functions such as digestion and urination
the nervous system works with what other system?
endocrine
to do its job, the NS uses:
sensory inputs, integration, and response
what does sensory input do?
detects changes (stimulii) inside and outside of the body
what does integration do?
processes and interprets the info
what does response do?
activation of muscles (motor output) or glands
what are the two types of nerve cells?
neurons and neuroglia
neurons
conduct impulses around the body, 10%
neuroglia
“nerve glue”, support, insulate, and protect neurons, 90%
the cell body contains what structures?
nucleus, cytoplasm, and organelles
processes are divided into
dendrites and axons
dendrites
brings impulses towards cell body
axons
send impulses away from cell body
neurons are classified by the number of —— extending from the cell body
processes
unipolar processes
one process
bipolar process
two processes
multipolar process
many processes
neurons can be classified by their function; afferent, efferent, and interneurons
afferent neurons- carry impulses towards CNS
efferent neurons- carry impulses away from the CNS
interneurons- connect afferent and efferent neurons
axons are wrapped in what
myelin
what forms myelin
schwann cells that wrap themselves around the axon
the outer layers of the schwann cells are called the
neurilemma
myelin helps the nerve impulses to travel more quickly by jumping over the what
Nodes of Ranvier
neuroglia cells are found in CNS and PNS. in the CNS, the four types are
astrocytes: support and anchor neurons to surrounding capillaries
microglia: provide immune response to CNS
ependymal: secrete and circulate cerebrospinal
oligodendrocytes: provide myelin insulation to neurons in CNS
neuroglia cells are found in CNS and PNS. in the PNS, the two types are
satellites: support and anchor neurons in the PNS
schwanns: provides myelin insulation to neurons in PNS
The brain and spinal cord are protected by 3 layers of connective tissue called the what?
meninges
dura mater
thick, tough layer
arachnoid membrane
thin, cobweb like layer
pia mater
thin layer containing lots of blood vessels
between the arachnoid layer and pia mater is the what
cerebrospinal fluid
the CSF protects the —– by preventing it from contacting the ——
brain; skull
the CSF also maintains the —— which controls homeostasis for the brain and prevents infection
blood-brain barrier
the CSF is produced in spaces within the brain called
ventricles
what are the four ventricles where CSF could be made
2 lateral ventricles, a third ventricle, and a fourth ventricle
clusters of capillaries in the ventricles called —— secrete CSF, which flows around the ventricles then is absorbed by ——-
choroid plexuses; arachnoid granulation into the blood
CSF is constantly being —-, —–, and —-
produced, circulated, and absorbed
what is largest part of the brain
cerebrum
the cerebrum is divided into two parts, divided by a bundle of fibers called
corpus callosum
the surface of cerebrum is covered in ridges called — and grooves called —-, and deeper grooves called —- that divide portions of the brain
gyri; sulci; fissures
the brain has 3 major layers (from superficial to deep)
Cerebral cortex: “grey matter”, made of cell bodies and dendrites
Cerebral medulla: “white matter”, made of myelinated axons
Basal nuclei: islands of grey matter
the names of the four lobes of the cerebrum and where they get their names from
they are named for their parts; frontal lobe, parietal lobe, occipital lobe, temporal lobe
frontal lobe
voluntary movements, reasoning and decision making, memory, ability to predict consequences of actions, planning, verbal communication- specifically broca’s area
what separates the frontal lobe from the parietal lobe
central sulcus
parietal lobe
sensations, visual-spatial processing, body positions
occipital lobe
visual processing- vision and memory of objects
the frontal lobe is separated from the temporal lobes by what
lateral sulcus
temporal lobes
memory, comprehension and pronunciation of words, sensations of smell and sound, emotional association of memories
diencephalon contains what three sections?
thalamus, hypothalamus, pineal gland
thalamus
relays sensory impulses to the cerebral cortex for processing and sorting
hypothalamus
tiny portion of the brain inferior to the thalamus.
-responsible for autonomic processes such as body temp, metabolism, and blood volume
-controls hormones released by pituitary gland
-part of the limbic system which has to do with emotions, pleasure, pain, etc
three sections of the brain stem
midbrain, pons, medulla oblongata
midbrain
“mesencephalon”
-relays info to cerebrum
-controls body movement and posture
pons
“bridge”
-almost completely made of “white matter” that links the cerebral cortex and cerebellum
-carries info from one side to another of the brain
-central control of breathing
medulla oblongata
-located just above the spinal cord
-transmits impulses between spinal cord and brain
-controls blood pressure, heart rate, swallowing, and coughing
cerebellum facts
-2nd largest part of the brain
-responsible for making movements more graceful and efficient
-“muscle memory”
spinal cord facts
-extends from medulla oblongata to lumbar vertebrae
-covered in meninges for protection
-relays impulses between the peripheral nervous system and the brain through 31 pairs of spinal nerves
-has a cross section
spinal cord cross-section
-butterfly of grey matter surrounded by white matter
-dorsal horns receive impulses from afferent nerves, then pass the impulses through the ventral horns to the efferent nerves
-dorsal and ventral roots contain the nerve fibers and join together to form a 2-directional spinal nerve
reflexes
preprogrammed responses, they pathway they take is called a reflex arc
5 elements of a reflex arc
receptor, sensory neurons, integration, motor neurons, effector
5 major types of sensory receptors
mechanoreceptors (touch), thermoreceptors (temp), nociceptors (pain receptors), chemoreceptors (chemicals), photoreceptors (light)
impulses produced in the skin are called —- sensations. these sensations include —, —, —, —, and —.
cutaneous; touch, heat, cold, pressure, and pain
types of touch receptors
free nerve endings, Meissner’s corpuscles, Merkel’s disks, hair follicle receptors, Ruffini’s corpuscles, Pacinian corpuscles
Free nerve endings
sense pain, temp, touch, and pressure
Meissner’s corpuscles
encapsulated nerve endings found in hairless skin that detects light touch
Merkel’s disks
detects light touch and pressure within the epidermis
hair follicle receptors
detect movement of hair
Ruffini’s corpuscles
detect deep pressure and stretching of skin
Pacinian corpuscles
encapsulated nerve endings that detect deep pressure and vibrations
touch is a —- sense because it includes many types of —- found all over the body.
general; receptors
sight, hearing, smell, and taste are —- senses because their receptors are —- in —- organs or in a small area (eye)
special; clustered; specialized
the eye is covered with the —, that meets the corners of the eye at the — — and the — —, and is lined with eyelashes
eyelid; medial commissure, lateral commissure
conjunctiva
thin membrane that covers the surface of the eyeball and the inner layer of the eyelid. it secretes mucus to keep the eye moist/to lubricate it
lacrimal apparatus
group of structures that also lubricate the eye
lacrimal glands
above the eye constantly release tears to cleanse and moisten the eye. tears contain mucus, antibodies, and lysozyme. the tears drain into ducts called the lacrimal cuniculi, then into the lacrimal sac and finally into the nasal cavity through the nasolacrimal duct
the eye is comprised of 3 tissue layers:
sclarea, choroid, & retina
sclarea
white of the eye; made of fibrous connective tissue; protects and shapes the eye
choroid
pigmented, vascular membrane that includes the iris and pupil
retina
contains photoreceptors that turn light energy into nerve impulses.
cornea
made of thick, transparent tissue. it allows light into the eye
iris
colored part of the eye, located behind the cornea. works with the pupil to regulate light entering the eye
pupil
opening in the center of the iris through which light enters
lens
semi-solid disc that directs light waves towards the retina. the lens is controlled by the ciliary muscles and suspensory ligaments. these both help bend/flatten the lens based on the distance of the image being viewed
aqueous humor
fluid in front of the lens; nourishes the cornea
vitreous humor
behind the lens; thick, jelly-like fluid that refracts light and fills the space between the lens and retina
two types of photoreceptors
rods: distributed all over the retina. responsible for vision in low light; extremely sensitive
cones: concentrated in center of retina, responsible for detection of colors; less sensitive
in order to see an image, light passes through the eye and hits the — — — (RPE) on the back of the eye. the light causes a — change that begins an —. this travels through the rods and cones, then — —, then — — before traveling to the brain via the optic nerve.
retinal pigment epithelium; molecular; impulse; bipolar neurons; ganglion cells
forea centralis
tiny pit that contains only cones so it is the point that provides the sharpest image
blind spot
where there are no photoreceptor. (where the optic nerve meets the eye)
myopia
near-sightedness
hyperopia
far-sightedness
the ear uses — to accomplish collecting and transferring sound vibrations to the auditory nerve
mechanoreceptors
auricle
collects sound waves that are then passed through the external auditory canal
tympanic membrane
“eardrum”, sound waves from the auricle vibrate this
middle ear contains what three bones (ossicles)
malleus, incus, and stapes; these amplify the sounds waves to the inner ear through a membrane called the oval window
choclea
bony snail-shaped structure containing membranes filled with fluid (perilymph). the perilymph then vibrates the basilar membrane, which has tiny receptor cells attached to it. the hairs of the receptor cells move against the tectorial membrane, depolarizing the ends of the nerve cells and beginning an action potential. when the action potential is transferred through the auditory nerve, the brain registers these impulses as sounds
maculae
receptor cell found in the choclea that helps to maintain static equilibrium; provides info to keep our head upright
— — (hairs) of the maculae are embedded in a gel-like membrane with calcium salts called —- resting on it
receptor cells; otoliths
