BY 30 – Fall 2001
18.1.
Cerebrospinal Fluid (CSF) Circulation
a. CSF is a clear, color-less fluid that is found in a series of spaces called the brain ____________________________, which are continuous with the __________________________ of the spinal cord. Both structures are lined by ________________________________ cells. CSF is also found within the _______________________ space.
b. Among the various functions of CSF, the CSF within the subarachnoid space serves as a __________________________, cushioning the brain from sudden movements which would otherwise cause collision with the surrounding bone. In addition, CSF provides the appropriate ___________________________ of extracellular fluids surrounding neurons and also serves as a medium for the transport of _________________________ and the removal of ____________________________________.
c. The brain ventricles include the two ________________________ ventricles, the _______________________ ventricle, and the ______________________ ventricle. Of these, the ________________________________ ventricles are located within the cerebral hemispheres, the 3rd ventricle is associated with the ________________________, and the ________________________ ventricle is associated with the lower brain stem.
d. The 2 lateral ventricles communicate with the __________________ ventricle via the ________________________. The 3rd ventricle is connected to the 4th ventricle by the _______________________. The 4th ventricle communicates with the subarachnoid space by the two ___________________ and the single ____________________________.
e. CSF is produced by a structure called the _______________________, which consists of blood capillaries in combination with _______________________ cells. These cells take fluid and solutes that leak out of the capillaries and secrete them into the __________________________. The total production of CSF per day is ______________________ while the total CSF volume is ______________________.
f. CSF passes from the subarachnoid space into venous blood through structures called ________________________. The veins which receive CSF are called ___________________________ because they lie within the dura mater. Any blockage can result in ______________________________, a condition in which CSF accumulates within brain ventricles causing them to expand, potentially damaging the surrounding nervous tissue.
18.2. The Brain
Stem
a. The brain stem consists of the _____________________________________, ________________________________, _____________________________, and the ____________________________________.
b. The most inferior portion of the brain stem is the ______________________, which is continuous with the _____________________________. Within this region fibers of the corticospinal tracts form the ________________________ which are two bulges located on the ___________________________ surface of the medulla. The ________________________ of the pyramids represents nerves fibers which cross from right to left and left to right. As a result the ____________________ cerebral hemisphere controls skeletal muscles on the right side of the body, and vice versa.
c. The medulla also contains two sensory nuclei called the _________________ nucleus and the ________________________ nucleus. Within these areas, axons of ______________________ neurons synapse on interneurons.
d. Within the medulla are a number of nuclei that control a variety of visceral functions, the two most important being the ______________________ center and the ______________________ center. The cardiovascular center controls _________________________ and __________________________ function, while the respiratory center controls the ______________________________.
e. The medulla contains nuclei related to cranial nerves ___________________, ___________________, __________________, ____________________, and ____________________.
f. The portion of the brain ventricles associated with the medulla is the ________________________________.
g. The ___________________ is just superior to the medulla and forms a bridge that connects the different parts of the brain. In addition, it contains nuclei for cranial nerves _________________, ________________, ______________, and _________________.
h. The portion of the brain ventricles located between the pons and cerebellum is the ___________________________.
i. Unlike other portions of the brainstem, the __________________ is organized similarly to the spinal cord with distinct regions of ______________________ matter and ________________________ matter. In this case, the gray matter forms the _____________________, which is located on the surface while the white matter, consisting of _________________________ is located centrally.
j. The portion of the brain stem involved in motor coordination is the _________________________, which compares _______________________ movements with what is actually happening thereby smoothing and coordinating complex skilled movements.
k. The most superior level of the brain stem is the ________________________, which contains the ____________________ on the ventral surface, which are made up of a variety of descending motor tracts. The dorsal surface is called the ____________________ which contains paired _____________________ and paired _______________________. Of these it is the ________________ that serve as reflex centers that govern eye, head, and neck movements in response to visual stimuli; while the __________________________ serve as reflex centers that govern head and neck movement in response to _____________________________ stimuli.
l. The midbrain contains several motor nuclei such as the __________________ and ___________________ which are involved in coordinated muscle movements. It also contains nuclei associated with cranial nerves _______________ and ___________________.
m. The ___________________ is a complex of neurons and fibers that runs the length of the brainstem and is involved in maintaining consciousness and awareness.
n. The portion of the ventricle system associated with the midbrain is the _____________________________.
18.3. The
Diencephalon
a. The two primary parts of the diencephalon are the ______________________ and __________________________.
b. The _______________________ serves as a sensory relay station for sensory information that is headed to the _________________________. Specifically axons of ______________________ involved in sensory pathways synapse on thalamic nuclei which in turn project to the cerebral cortex.
c. The _______________________ controls many body activities, serving as an integrator for many visceral reflexes. Specifically, its ability to control homeostasis is dependent on its control over the _______________________ system and the __________________________ system.
d. Among the different functions of the hypothalamus are ______________________________________________________________, ______________________________________________________________, ______________________________________________________________, and ___________________________________________________________.
e. The hypothalamus is situated above the _______________________ gland, an endocrine glands whose hormones control _________________________ and exert their effects on body processes. The pituitary gland is under the control of the ___________________________.
f. The hypothalamus controls eating habits through its ____________________ centers which receive input from the __________________________ system. _________________________ centers are stimulated when the osmolarity of _____________________________ fluids increase, which prompts the desire to drink fluids.
g. The hypothalamus also monitors the temperature of ___________________, and activates the autonomic nervous system when the temperature deviates from the __________________________.
18.4. The Cerebrum
a. The portion of the brain where most thought processes take place is called the _________________________. Like the cerebellum, this portion of the brain also has a superficial layer of gray matter called ________________________ while the white matter is located deeper.
b. The cerebral cortex is organized into a series of folds called ______________ and grooves called _____________________ or _______________________. Of these, the ________________________ separates the cerebrum into right and left halves, each referred to as a cerebral _________________________. The two cerebral hemispheres are connected by a band of white matter called the ________________________________.
c. Each cerebral hemisphere is divided into lobes called the ________________, __________________, _________________, and ______________________. These lobes roughly correspond to the _______________________ that cover them.
d. The __________________________ sulcus separates the frontal lobe from the parietal lobe.
e. The __________________________ sulcus separates the frontal lobe from the temporal lobe.
f. The _____________________________ sulcus separates the parietal from the occipital lobe.
g. The _____________________ are pairs of nuclei located deep to the cerebral hemispheres that are involved in automatic skeletal muscle function, and for setting muscle tone.
h. The ________________________ system refers to a variety of structures that encircle the upper part of the brain stem and corpus callosum. It functions in the emotional aspects of behavior and memory.