Brain Flashcards
(96 cards)
part of the CNS enclosed in the
cranial cavity
Brain
•composed of 100 billion
neurons & 10 to 15 trillion
neuroglia
• ave. wt.: 1.5 kg
Brain
The average weight of the brain?
1.5 kg
• receives 15%-20% of the blood
pumped by the heart.
Brain
• highly metabolic organ
• consumes 80% of glucose &
15% of O2
that body uses
• glucose & O2 not stored in brain
Brain
• is continuous with the spinal
cord and consists of the
medulla oblongata, pons,
midbrain & reticular formation
Brain Stem
• located above the brain stem &
consists mostly of the thalamus
& hypothalamus
DIENCEPHALON
• forms the bulk of the brain,
supported on the diencephalon &
brain stem
CEREBRUM
• located posterior to the brain stem
CEREBELLUM
• bony structure protecting the
brain
SKULL/CRANIUM
• consistent with the spinal
meninges
• consists of 3 layers: the
outermost dura mater, middle
arachnoid mater & innermost
pia mater
MENINGES
• a clear, colorless liquid w/c
contains small amounts of
glucose, proteins, lactic acid,
urea, cations (Na+, K+, Ca++
,
Mg++), & anions (Cl-
, HCO3-
) &
some WBCs
CSF
Average volume of CSF
80-150 mL
• functions:
✓ carries needed chemicals from
the blood to neurons &
neuroglia
✓ removes wastes produced by
brain & spinal cord cells
✓ protects the spinal cord & brain
from chemical & physical injury
CSF
• circulates through the
subarachnoid space around the
brain & spinal cord, through
cavities in the brain known as
ventricles & through the
central canal of spinal cord
CSF
•related to CSF
Production & Absorption
•space between pia mater &
arachnoid mater
•surrounds brain & spinal cord
•where CSF circulates
Subarachnoid
•related to CSF
Production & Absorption
•CSF-filled chambers in the brain
there are four namely:
✓ two lateral ventricles (found in each
hemisphere of cerebrum)
✓ one third ventricle (found inferior
to lateral ventricle
✓ one fourth ventricle (found bet.
brain stem & cerebellum inferior to
third ventricle)
VENTRICLES
•related to CSF
•Production & Absorption
are specialized networks of
capillaries in the walls of the
ventricles lined w/ ependymal
cells
•where CSF is produced from blood
plasma
CHOROID PLEXUS
•related to CSF
•Production & Absorption
fingerlike extensions of arachnoid
mater
•gradually absorbs CSF
ARACHNOID VILLI
•related to CSF
Production & Absorption
•large veins w/in dura mater where
CSF drains & becomes blood
plasma again
CRANIAL VEINOUS SINUSES
is the part of the brain between
the spinal cord & diencephalon
BRAIN STEM
•MAJOR REGIONS of the Brainstem
• or “medulla”
• a continuation of the spinal
cord
• forms the inferior part of the
brain stem
MEDULLA OBLONGTA
• its gray matter contains
several nuclei:
•MAJOR REGIONS of the Brainstem
• within its white matter are all
ascending & descending
tracts extending between the
spinal cord & other parts of
the brain
• where most sensory & motor
fibers decussate
MEDULLA OBLONGTA
•NUCLEI of the Medulla
• adjusts the force & rate of
heart beat
CARDIAC CENTER