Chapter 14: The brain and Cranial Nerves Flashcards
when is brain fully grown and what is the final weight?
age 20, 3 lbs
brain requires __% of the total O2 content
20%
there is permanent damage with more than ___ min without oxygen
5
Has a limited storage capacity for ______ and must be continually supplied
deficiency may produce?
glucose
mental confusion, dizziness, convulsions, and unconsciousness
major parts of the brain
brain stem, diencephalon, cerebrum, and cerebellum
Protective Covering of the Brain
cranial bones and the cranial meninges which are continuous with the spinal meninges
- Three extensions of the meningeal layer of the dura mater that separate parts of the brain
a. Falx Cerebri:
b. Falx Cerebelli:
c. Tentorium Cerebelli
Falx Cerebri
separate right and left cerebral hemisphere
falx cerebelli
found between right and left halves of cerebellum
tentorium cerebelli
separate cerebellum from occipital lobe
Description of Cerebrospinal fluid (CSF):
clear, colorless fluid with a total volume in the adult of 100-200 ml
four (4) CSF filled cavities within the brain
ventrices
- lateral ventricle
- 3rd ventricle
- 4th ventricle
- capillaries
- Lateral Ventricles (or First and Second Ventricles
principle site of CSF production
Third Ventricle
drains the lateral ventricles
Fourth Ventricle
drains 3rd ventricle
- CSF is formed by filtration of blood water through a network of ____________ and __________ cells called __________ _________.
filtration of blood water through network produced at rate 1 liter per dayy and epidemal cells (coroid plexus)
C. Pathway of CSF Flow: __________ __________ → __________ __________ → __________ __________ → __________ __________ → __________ _________
lateral ventrices → foramen of monroe → 3rd ventricle → 4th ventricle → aqueduct of sylvius (cerebral aqueduct) → central canal of spinal cord
Most of the CSF is reabsorbed by
arachnoid villi of the superior sagittal blood sinus
hydrocephalus
if CSF cannot circulate or drain properly due to an obstruction in the ventricles or subarachnoid space, a buildup will occur causing increased pressure on the brain
symptoms: headache, nausea
Medulla Oblongata (Develops from the Hindbrain) is Continuous with
upper part of the spinal cord
white matter in Medulla oblongata are portions of ______ tracts and _____ tracts
2 parts
portions of myelinated motor (descending) and sensory (ascending) tracts
a. Pyramids: largest motor tracts
b. Decussation: neurons in the left cerebral cortex control skeletal muscles on the right side of the body
Gray Matter in medulla oblongata are _____ for origin for CN ____ through ____ and _________ centers
control 4 things
nuclei, CN 8 through 12, autonomic reflex
a. Respiratory (regulates breathing rhythm)
b. Cardiac Control (regulates force and rate of heartbeat)
c. Vasomotor (vessel vasoconstriction)
d. Coughing, vomiting, sneezing, swallowing, and hiccupping
Pons (develops from the Hindbrain) separates
medulla from the midbrain
White Matter in pons ______ different levels of the brain by way of ______ and relays ______
interconnects, tracts
nerve impulses related to voluntary skeletal movements from the cerebral cortex to the cerebellum
Gray Matter in pons are _____ for origin of CN ___ ___ ___ ___ and ______ ______ centers
nuclei, CN 5, 6, 7, 8, pneumotaxic & apneustic
Midbrain connects
pons and diencephalon
Cerebral Aqueduct transports
CSF
White Matter tracts in Midbrain are organized into ____ ______ that convey _____ and _____ impulses
cerebral aqueducts, motor, sensory
Gray Matter in Midbrain are _____ for origin for CN ___ and ___ and the ______ _______
nuclei, 3 and 4, corpora quadrigemina (two pairs of rounded nuclei)
2 parts of gray matter in midbrain
centers for what?
a. Superior Colliculi: visual reflex center
b. Inferior Colliculi: auditory reflex center
Reticular Formation
column of gray matter interspersed among fibers of white matter that extends from the medulla to the thalamus
Ascending sensory pathways are relayed to the _____ and then the _____
thalamus and then the cerebral cortex
Reticular Activating System (RAS) functions
- regulation of muscle tone (motor function)
- arousal from sleep (stim from eyes, ears, skin)
- maintain consciousness & alertness
Gray Matter in cerebellum description
convoluted outer surface called the cerebellar cortex
Two cerebellar hemispheres are interconnected by region called the __________
vermis
Cerebellar Nuclei is made up of
several, gray matter
White Matter in cerebellum is found and arranged into 3?
found deep in the cortex
three (3) cerebellar tracts called the superior, middle, and inferior cerebellar peduncles
cerebellum coordinates all
somatic motor activity
superior tract in cerebellum is made up of _____ that carry _____ from _______ to _____ (3)
mostly efferent fibers that carry impulses from cerebellum to midbrain, thalamus and cortex
Cerebellar middle tract carries
fibers form cortex
inferior cerebellar peduncle
ascending afferent fibers from cord and medulla
4 cerebellar functions
- Error Control in Body Movements: executes the movement intended by the cerebral cortex
- Predictive Function: detects speed and progress of body movements
- Efficient Body Movement: influences antagonistic muscles
- Maintains Muscle Tone: to maintain posture and equilibrium
Injury to the cerebellum results in
Cerebellar Ataxia
