Chap 13 Flashcards
The major parts of the adult brain are directly derived from the embryonic
brain vesicles
At birth, the neonatal brain looks very much like an ____ and almost all the neurons the brain will ever have is _____ _____
adult, already present
What 4 structures is the adult brain divided in and average weight
-Cerebrum
-Diencephalon
-Cerebellum
-Brainstem
~3 lbs
Cerebrum
- responsible for higher functions
- divided into left and right hemispheres
Diencephalon
consists of thalamus, hypothalamus, limbic system, and pituitary gland
Cerebellum
- body movements
- maintain balance
- divided into hemispheres
Brainstem
- consists of midbrain, pons, and medulla oblongata
- involved in autonomic functions
Surface of cerebrum consists of
gyri and sulci,
deeper sulci called:
fissures
Cerebrum divided into lobes
- Frontal
- Parietal
- Occipital
- Temporal
Cortex of cerebrum is made of ____ ____, the deeper layer is called ____ ____
gray matter, white matter
Gray matter is made of
neural cell bodies
White matter is made of
myelinated axons
Basal Nuclei are clusters of
gray matter that lie in deeper regions of brain
Large hollow chambers that are formed in the cerebrum during embryonic development
Lateral ventricles
Lateral ventricles are connected via the
interventricular foramen to the 3rd ventricle
4th ventricle is located posterior to brainstem and Is connected to the 3rd ventricle by
Cerebral Aqueduct
Cerebrospinal Fluid
fills ventricles
Ependymal cells
line ventricles
Brain is protected in which 3 ways
- the bony cranium
- the meninges
- cerebral spinal fluid (CSF)
Meninges
the dense irregular connective tissue coverings of the brain and spinal cord
Cranial Meninges consist of 3 layers
- Dura mater
- Arachnoid mater
- Pia mater
Bone surrounded by
periosteum
Cranial dura mater has what 2 layers
- external periosteal layer
- internal meningeal layer
Biochemical protection of brain
- blood brain barrier
- cerebrospinal fluid
several mechanisms that isolate CNS from general circulation
blood brain barrier
cranial meninges are continuus with those of
spinal cord
Dura mater
2 layers- both are fibrous
- outer – fused to periosteum
- inner – meningeal layer
large venous sinuses
dural sinuses
venous sinuses, tissue fluids, blood vessels, dural sinuses are found btwn
layers of dura mater
Layer of epithelium with web like extensions to pia mater
Arachnoid mater
Subarachnoid space filled with
CSF (cerebral spinal fluid)
Covers entire surface following folds
Pia mater
Sheets of dura mater that dip into deep folds of brain and return to surface
dural folds
Whats located in dural folds
dural sinuses
in the longitudinal fissure btwn 2 hemispheres of cerebrum
falx cerebri
btwn cerebrum and cerebellum
tentorium cerebelli
btwn 2 hemispheres of cerebellum
falx cerebelli
holds brain in position “seat belt”
dural folds
floats brain
cerebrospinal fluid
Cerebrospinal fluid location
- 4 ventricles
- subarachnoid space
- central canal
Cerebrospinal fluid functions
- Cushions
- supports
- transports
Cerebrospinal fluid is produced by
choroid plexuses
choroid plexuses
capillaries surrounded by specialized ependymal cells
CFS is low in
protein and K+
Proteins, amino acids, waste products, most drugs and K+ are NOT permitted access in the
blood-brain barrier
Total volume of CSF at any time
150mL
Pressure remains _____ in the CSF
constant
Meningitis
inflammation of meninges
drainage of CSF through
arachnoid granulations
vascular endothelium around brain capillaries differs from most other organs of the body in that if forms
tight junctions
Blood brain barrier function
isolate tissue of CNS from general circulation
2 hemispheres are separated by the
longitudinal fissure
basal nuclei are clusters of
gray matter
Basal nuclei functions
- inhibiting unnecessary movement
- skeletal muscle tone
- body positioning
Primary Sensory (Somatosensory) Cortex
- parietal lobe
- pressure, pain, and temp
Primary motor cortex
-voluntary movements
Primary Auditory Cortex
-cochlear receptors
What’s located in the temporal lobes, orbitofrontal cortex, limbic system
Olfactory Area
Primary Visual Area
-occipital lobe
Visual Association Area surrounds the ___ ____ ____ and stores info that allows us to ____ _____ _____
- primary visual cortex
- recognize visual information
Association Areas
interpret incoming sensory info
4 integrative areas
receive input from many association areas
a) Prefrontal cortex
- receives info from associations areas
- interprets info and registers abstract intellect
b) General Interpretive Area
- LH only
- interpret what is read and heard
c) Speech Center (Broca’s Area)
- regulates breathing and vocalization muscles (required for speech)
- LH only
d) Frontal Eye Field
- RH and LH
- controls learned eye movements
Left hemisphere (LH)
- speech
- interpretive
- writing
- analytical tasks
Right hemisphere (RH)
- analysis by touch
- spatial visualization
- recognizing faces
- analyzing emotional
- content of conversations
Cerebral white matter provides ____ btwn cortical tracts and ___ ____
communication, lower structures
Bundles of axons in CNS =
tracts
Tracts equivalent to nerves in the
PNS
Association fibres
tracts that transfer signals within a hemisphere
Commissures
tracts that transfer btwn hemispheres
Projection fibres
tracts send signals to the spinal cord
White matter of cerebrum =
tracts
Prefrontal Cortex
determines intellect, personality, complex learning abilities, and memory
3 Parts of Diencephalon
- Epithalamus
- thalamus
- Hypothalamus
Epithalamus
- contains pineal gland
- secretes melatonin
- regulates day-night cycles
Thalamus
receive and relay sensory info
-known as ‘Gateway to the Cortex’
hypothalamus
- coordinates voluntary and autonomic functions
- coordinates NS and endocrine system
- produce emotions and behavioural drives
- regulation of body temp
- Control of circadian rhythms
General function of a brainstem nuclei
relay center
Reticular Activating System (RAS)
- formed within midbrain, pons, MO
- stimulate cortex
- brains overall state of arousal
Functions of the limbic system
- establishes emotional states (amygdala)
- emotional drives (amygdala)
- memory storage (hippocampus)
T or F, Cranial nerves can service both the somatic and autonomic nervous systems
True
I Olfactory
sends sensory info from nasal cavity to olfactory bulbs
II optic
sends visual info to the optic chiasma
III Oculomotor
- 4 of 6 eye muscles
- controls pupil contractions
IV Trochlear
-1 eye muscle
V Trigeminal
-sensory fibres to face and mouth
VI Abducens
1 muscle of eye
VII facial
- facial expression
- lacrimal and salivary glands
VIII Vestibulocochlear
sound and balance
IX Glossopharyngeal
swallow and taste
X Vagus
heart, lungs, and gut
XI Accessory
muscles of larynx and pharynx
XII Hypoglossal
swallowing and speech
Cranial nerve functions
- carry sensory info
- controls muscle
- provides parasympathetic innervation