Chapter 2 Flashcards
Forebrain (cerebrum)
Longitudinal fissure Sulci and gyri Central sulcus Lateral sulcus Parieto-occipital sulcus Frontal lobes Parietal lobes Temporal lobes Occipital lobes Corpus callosum Lateral ventricles Olfactory tracts Olfactory bulbs
Forebrain (diencephalon)
Third ventricle Thalamus Hypothalamus Infundibulum Pineal gland Optic nerves Optic chiasm Optic tracts
Midbrain
Cerebral aqueduct
Corpora quadrigemina
Cerebral peduncles
Hindbrain
Cerebellum
Pons
Medulla oblongata
Fourth ventricle
Cerebellum
Vermis
Cerebellar hemispheres
Arbor vitae
Brain
Dura mater
Arachnoid mater
Pia mater
Cervical part of spinal cord
Dura mater Arachnoid mater Pia mater Dorsal roots - Dorsal root ganglia Ventral roots Cervical spinal nerves Cervical enlargements
Cranial cavity
Dura mater Cranial nerves (I-XII) Internal carotid arteries Diaphragma sellae Medulla oblongata/spinal cord Vertebral arteries
Dura mater
Dural septa
Falx cerebri
Tentorium cerebelli
Falx cerebelli
calvaria
skullcap
wedge cute
cutting pattern not to scale
nervous system
receives, processes, and/or sends both sensory inputs and motor outputs of the body
nervous system is composed of two main parts
the central nervous system (CNS) and the peripheral nervous system (PNS)
CNS
brain and spinal cord, which is covered by protective layers called the dural layers or meninges
superficial to deep layers
dura mater, arachnoid mater, and pia mater
Dura mater
is the thickest and strongest layer, it helps keep the brain and spinal cord in specific placement within the cranium and vertebrae, it protects both the brain and spinal cord
arachnoid matter
also aids in absorption of the cerebrospinal fluid (CSF)
dura mater types
falx cerebri, falx cerebelli, and tentorium cerebelli
two cerebral hemispheres
cerebral cortex, cerebral white matter, and basal nuceli (basal ganglia)
functional part of cerebral cortex
thin layer of neurons
each hemisphere receives sensory impulses from the opposite side of the body—
if your right hand touches a hot stove, that gets processed by the left side of the brain. Motor impulses are then dispatched from the left cerebral cortex to the right side of your body to quickly remove your right hand from the hot stove.
cerebral cortex requires
an intrinsic communicative ability with the deeper parts of the brain, especially the thalamus
thalamus & cortical
if the thalamus were damaged, there would be a greater loss of cerebral function experienced by the patient, compared to a patient who only experienced cortical damage. This is because the thalamus triggers excitation of the cortex to initiate cortical activity. Thus, both the cerebral cortex and the thalamus are often thought of as one functioning unit.
cycle of CSF
- formed by choroid plexuses from the blood plasma
- circulates through ventricles into subarachnoid space
- CSF flows through subarachnoid space
- returns to the dural venous sinuses via arachnoid villi
how often is CSF is replaced?
8 hours
major function of CSF
Support and cushion brain and cord; help nourish CNS organs
cerebral white matter
“contains fiber pathways” that provide a link between cerebral cortical areas (higher brain; cerebral cortex) with each other as well as with subcortical (lower brain; medulla, pons, cerebellum, diencephalon) structures.
Links in the brain
provide the brain a network of distributed circuits that enable sensorimotor function, intellect, and emotion
3 structures as cerebral white matter
the corpus callosum, the fornix, and the anterior commissure
basal ganglia
composed of different subcortical nuclei and work closely with other parts of the brain (including the cerebral cortex) by receiving and sending most input and output signals from the cerebral cortex
A large component of the basal ganglia includes
carrying out patterns of motor activity. Examples includes writing, throwing a ball, shooting a basketball, etc
basal ganglia play a role
in human behavior & emotions
used for communication with each other
cerebral white matter or basal ganglia, the cerebral hemispheres, cortical level, & subcortical level
The cerebral hemispheres contain 4 different lobes
frontal, temporal, parietal, and occipital
Frontal lobe
motor control, some speech, cognitive thinking and even some aspects of personality
functional areas specific to frontal lobes are
primarily motor areas
such as the primary motor cortex, frontal eye field, and Broca’s area (the part of our brain that helps us produce speech)
Prefrontal association area
incorporates cognitive thinking
Parietal lobe
reading, writing, calculations, and sensations, such as hot, cold, touch, or pain
Functional areas specific to parietal lobes are
primarily sensory such as the somatosensory cortex, also called the postcentral gyrus
Temporal lobes
hearing, speech, and memory
functional areas specific to temporal lobes
primarily sensory including auditory function areas
3 main gyri present in the temporal lobe
superior temporal gyrus (STG), middle temporal gyrus (MTG), and inferior temporal gyrus (ITG)
STG
contains an auditory association cortex and also helps process eye movements
MTG & ITG
both memory and language processing centers
Occipital lobe
processing vision input, the visual cortex
4 major lobes are separated by
grooves, or sulci
central sulcus
marks a border between frontal and parietal lobes
Parieto-occipital sulcus
marks a border between the parietal and occipital lobe
Diencephalon, 3 components
epithalamus, thalamus, & hypothalamus
epithalamus
helps to connect the limbic system and it contains the pineal gland, which is known for its melatonin secretions
thalamus
important for communication with the cerebral cortex, it helps relay sensory impulses to the cerebral cortex for interpretation
hypothalamus
carries a multitude of functions (collectively called “vegetative functions”), which are largely centered around the autonomic nervous system
hypothalamus regulates
body temperature, food intake, water balance, thirst, circadian rhythms, hormonal outputs that act on the anterior pituitary gland, or synthesizing hormones that are stored in the posterior pituitary
cerebellum
processes information from the cerebral cortex by providing “instructions” based on both sensory & motor inputs that allow for coordinated muscles movements.
Muscle movements processed by the cerebellum
running, playing an instrument, and even speech
Brain stem
midbrain (mesencephalon), pons, and medulla
3 function of the brain stem
1) a pathway to transmit information between the spinal cord and cerebrum
2) control of consciousness and vital functions (e.g. respiration)
3) contains many cranial nerve nuclei.
midbrain
corpora quadrigemina, cerebral aqueduct, and cerebral peduncles
corpora quadreigemia
contains 2 paired “bumps”, resulting in 4 “bumps” total, which contain visual and auditory reflex centers
superior colliculus
The superior “bumps”, are move involved with vision
inferior colliculus
inferior “bumps”, are more involved with hearing
cerebral penduncles
bundles of nerve fibers that aid in transmission of information from the cerebral cortex to the cerebellum. Peduncle means, “little foot” in Latin, “little feet of the cerebrum”
pons and medulla work together to
control many subconscious activities and reflexes of our bodies such as: regulation of arterial pressure and respiration, and reflexes such as the feeding reflex
carpus callosum
the largest white matter structure in the brain, is a major connector of the cerebral hemispheres to enable communication between both sides of the cerebrum
fornix
forms one of the major white matter tracts that makes up the limbic system and it aids in transferring afferent and efferent information between other brain structures
fornix connects what structures?
hypothalamus, thalamus, and mammillary bodies
limbic system
associated with controlling both our emotional as well as our motivational drives
mammillary bodies
are part of the limbic system and help us process memory and smell.
anterior commissure
important link between the cerebral hemispheres and is involved with processing acute pain sensations and smell
hormone regulators
hypothalamus, especially hormones involved with controlling reproduction function, is connected to the pituitary gland by the infundibulum, and because of its connection, the hypothalamus releases “releasing hormones” to trigger hormone release from the pituitary gland
pituitary gland
produces and releases important hormones involved with reproduction as well as hormones that regulate homeostatic functions of the body, such as blood pressure regulation or thyroid activity
spinal cord
transmit both motor outputs and sensory inputs by rootlets, or roots, that are located on the ventral and dorsal side of the spinal cord
ventral roots
carry motor output
dorsal roots
carry sensory input
ventral and dorsal roots
spinal nerves
spinal nerves split into
ventral and dorsal rami
The ventricular system of the brain is important for
cerebrospinal fluid (CSF) production and circulation
Cerebrospinal fluid is important
for cushioning and protecting the brain, but also to assist in homeostatic regulations of the cerebral interstitial fluids and facilitate brain development
choroid plexuses
clusters of anastomosing capillaries enclosed by pia mater and a layer of specialized cells called ependymal cells
How can CSF exit the lateral ventricles and enter the third ventricles?
the interventricular foramen
The CSF continues to flow from the third ventricle to the fourth ventricle?
cerebral aqueduct
how does it get to the spinal cord?
The CSF exits the fourth ventricle via specific foramen into the subarachnoid space.
dural venous system
CSF will become reabsorbed into the dural venous system found within the dural layers surrounding the brain
CN I
Olfactory nerve
-Sensory nerve, carries impulses of smell
CN II
Optic nerve
- Sensory nerve; carries afferent impulses for vision
- Fibers arise from retina of eye to form optic nerve and passes through optic canal of orbit, then converges to form the optic chiasma and then continue on into thalamus where they synapse. From there, thalamic fibers run to carry the message of vision to the occipital cortex where it is then interpreted.
CN III
Oculomotor nerves
- Chiefly motor neurons and a few proprioceptive afferents
CN IV
Trochlear Nerves
-motor nerves
CN V
Trigeminal nerve; largest of the cranial nerves extending from pons to face
- sensory nerves
Trigeminal nerve
opthalamic - superior orbital fissure
maxillary - foramen rotundum
mandibular - foramen ovale
CN VI
Abducens nerves
-Primarily motor; innvervates lateral rectus muscle
CN VII
Facial Nerve
-Mixed nerves that are chiefly motor nerves with 5 branches
CN VIII
Vestibulocochlear nerves
-Mostly sensory; transmits afferent impulses for senses of equilibrium (vestibular division), hearing (cochlear division)
CN IX
Glossopharyngeal nerve
- Mixed nerves that innervate part of tongue and pharynx and provides parasympathetic motor fibers to parotid gland
- Sensory fibers conduct taste and general sensory such as touch or pain from pharynx and posterior tongue, and from baroreceptors of carotid sinus
CN X
Vagus nerve
-Mixed nerves; nearly all motor fibers are parasympathetic except for those serving skeletal muscles of pharynx and larynx
CN XI
Accessory nerves
- Mixed nerves; mainly motor, supplied to trapezius and sternocleidomastoid to move head and neck
- Form rootlets that emerge from spinal cord; arise laterally from superior region of spinal cord (C1-C5) and pass upward along spinal cord and enters skull via foramen magnum.
CN XII
Hypoglossal nerves
-Mixed nerves but mainly motor; serves the tongue
Arises as nerve fibers from olfactory epithelium in nasal cavity that goes through cribiform plate and synapses in olfactory bulb
olfactory nerve, CN I
passes through optic canal (medial to superior orbital fissure) of orbit
optic nerve, CN II
pass through bony orbit via the superior orbital fissure to the eye
oculomotor, CN III
enter orbit via superior orbital fissure along with oculomotor nerves
trochlear, CN IV
Sensory impulses from anterior forehead, upper eyelid, nose, nasal cavity and lacrimal gland
opthalamic division
superior orbital fissure
Sensory impulses from nasal cavity, upper lip, and lower eyelid
maxillary division
foramen rotundum
Sensory impulses from anterior tongue, lower teeth, skin of chin; also innervates some muscles of mastication (motor)
mandibular division
foramen ovale
leave inferior pons and enter orbit via superior orbital fissure
abducens, CN VI
from pons and enter temporal bone via internal acoustic meatus running within the bone through the inner ear cavity and emerges from stylomastoid foramen
facial, CN VII
within inner ear of temporal bone and pass through internal acoustic meatus to enter brain stem at pons-medulla border
Vestibulocochlear, CN VIII
from medulla and leave skull via jugular foramen towards throat
Glossopharyngeal, CN IX
from the medulla, passes through the skull via jugular foramen, and descends through neck region into thorax and abdomen
vagus, CN X
enters skull via foramen magnum
accessory, CN XI
from medulla and exit the skull via the hypoglossal canal and travel towards the tongue
hypoglossal, CN XII
Test this nerve by examining pupil shape and size with a penlight and also test eye movement by having patient follow objects with their eyes
CN III & CN IV
eye will not move laterally
CN VI
Test for nerve function by making facial expressions, taste ability, and tearing from ammonia fumes
CN VII
parasympathetic impulses to the lacrimal glands, nasal and palatine glands, and submandibular and sublingual glands
facial nerve
Use a tuning fork to assess hearing
CN VIII
Check uvula position, gag and swallowing reflexes; swallowing will be impaired if this nerve is damaged
CN IX
Injury to these nerves would result in head tilted downwards and difficulty shrugging
CN XI
Injury would cause difficulties in speech and swallowing; unable to protrude tongue
CN XII
