Neural Bases - Chapter 7 Flashcards
the human brain weighs _ lbs = 2% of body weight and consumes 7-% of bodies energy
3
- ________consists of the right and left hemispheres – 82% of the brain’s mass
cerebrum
cerebral cortex made-up of neurons or bodies, grey matter
surface of the brain
protects the brain against penetration injuries
Outer bony layer: the skull
o The membrane that adheres to the skull consists of dense layers of fibrous connective tissue
o Creates compartments for the cerebral hemispheres and the cerebellum
o Epidural space – space between the skull and the dura mater
o Subdural space – the space under the dura
Dura matter
thin delicate connective tissue made up of collagen and elastic fibers
o Subarachnoid space – space below the arachnoid matter; includes blood vessels and cerebrospinal fluid
arachnoid matter
final and innermost layer; tightly adheres to the gyri and sulci of the brain
pia matter
_____ _____ ____ is located in the walls of the CNS blood vessels
* The cells are tightly packed and the cell layer is semi-permeable – let smaller molecules from the bloodstream and keep the larger substance out
* Protects the brain from foreign invaders hormones antibodies and other substances that might affect the brain
* Not developed completely invitro and young infants – medications/toxins can cause neuronal damage
blood brain barrier
- The brain consumes 20% of the body’s oxygen
- Oxygen nourishes the brain and without oxygen, the brain starves and quickly dies
the cerebral arteries
- The vertebral basilar system and the carotid artery form a circular array of blood vessels
- Helps to promote equal blood pressure and blood flow to all areas of the brain
- Example: if one of the carotid and basilar arteries
circle of willis
The _______ _______ is a major blood vessel originating from the subclavian artery. It travels through the cervical vertebrae and into the skull, supplying oxygen-rich blood to the brainstem, cerebellum, and posterior parts of the brain. Its function is crucial for maintaining proper brain circulation.
vertebral artery
The external carotid artery supplies blood to the face, neck, scalp, and upper part of the thyroid. The internal carotid artery travels deeper, delivering oxygenated blood to the brain, eyes, and forehead. Together, they ensure essential blood flow for both superficial and deep structures of the head and brain, supporting critical functions.
common carotid artery
- Acts as a waste disposal system moving the oxygenated blood away from the brain and using CSF from the ventricular system
- 2 main cerebral veins:
o Superficial cerebral vein-blood from the cerebral cortex and subcortical white matter
o Deep cerebral veins – blood from subcortical gray matter [thalamus and hippocampus]
the venous system
deep grooves
fissures
shallower grooves
sulci
hills
gyri
increases the surface area of the brain as well as the number of neurons
sulci and gyri
There are prominent gyri and sulci in each lobe of the cerebral hemispheres
true
runs from front to back and separates the two hemispheres
- Longitudinal fissure
Rolandic fissure, separates the frontal lobe from the parietal lobe
Central fissure
Sylvian fissure, separates the frontal and parietal look from the temporal lobe
lateral fissure
Lissencephaly, Smooth brain- causes severe motor, intellectual and psychological disability
disorders of sulci/gyri: Agyria
- 6 distinguishable layers of tissues made-up of pyramidal and non-pyramidal neurons
- Pyramids – pyramidal in shape and are motor in nature
- Non pyramid cells-smaller, star-shaped and involved in sensory function
layers of the cerebral cortex
lies at the front of the brain just above the eyes
o Functions include reasoning, planning, and voluntary motor movements and is important for expressive language and planning execution of speech
frontal lobe
lies posterior to the central fissure and superior to the lateral fissure
o Touch sensory perception, interpretation, and integration
parietal lobe
lies inferior to the parietal lobe
o Processing of auditory information including speech and memory functions [long-term memory]
temporal lobe
posterior to parietal and temporal lobe
o Visual processing
occipital lobe
- Each hemisphere is not a mirror image of the other rather it functions uniquely
o An example:
Language is a hemispheric specialization
96% of right-handed people have their language lateralized to the left hemisphere
Meaning these people could be left brain dominant or both motor language function
Reading is localized bilaterally or in the right hemisphere
Similarly extra-linguistic features such as intonation stress and inflections are localized
hemispheric specialization
a band of axonal callosal fibers that connects two cerebral hemispheres and communicates with one another
corpus callosum
o Genu – anterior part
o Isthmus - middle part
o Splenium - posterior part
parts of corpus callosum
- Large bundles of neurons make connections within cerebral hemispheres
- Superior longitudinal fasciculus (SLF) – and association fiber that connects the back and front of the cerebrum and the four brain lobes
- Arcuate fasciculus (AF) – connects two important speech and language areas that is the Broca’s area in the inferior frontal lobe with the Wernicke’s area in the superior temporal lobe.
- Damage to the AF – conduction aphasia resulting in difficulty in repeating words
intra-hemispheric connections
- Commonly known as stroke – 5th leading cause of death in the United States interruption to the brain’s blood supply
- Two types of CVS: ischemic CVA and hemorrhagic CVA
disorders of cerebral hemispheres: cerebrovascular accident [CVA]
- Bleeding type of CVA and divided into intra-axial hemorrhage and extra-axial hemorrhage
o Interaxial hemorrhage – involves blood from the ruptured blood vessel inside the brain
o Extra axial hemorrhage – blood is inside the skull but outside the brain [around the meninges] - Hematoma – collection of blood in a tissue or space
- Aneurysm – abnormal ballooning of an artery’s wall
disorders of cerebral hemispheres: Hemorrhagic CVA:
- Loss of blood flow to the brain usually due to the blockage
o Originates either in the blood vessel itself,
o Somewhere else and lodges in a blood vessel [embolism],
o Transient ischemic attack [TIA] – loss of blood flow to the brain that is temporary and CVA resolves in a matter of minutes or within 24 hours - Damage is focal in nature – the area deprived of oxygen dies in about one hour or less this tissue necrosis and the dead tissue is called an infarct
- Ischemic penumbra – the area surrounding the infarct that lost some level of blood flow but has retained enough to stay alive
disorders of the cerebral hemisphere: Ischemic CVA
- Traumatic blow to the brain that impairs functioning of the brain; open head injury and close head injury
TBI
penetrates the skull and causes damage to the brain
open head injury
forces that cause damage to the brain but without penetrating the skull
o Acceleration – deceleration closed head injury involves the body traveling at a high rate of speed and then suddenly coming to a stop, for example, a car accident.
o Closed head injury impact based-the body is stationary, but a moving object impacts the head
close head injury
diffuse damage to the brain structures; causing coup or counter-coup damage
* Can result in aphasia, right hemisphere syndrome, dysarthria, apraxia, and or dysphagia
TBI damage
Non-progressive brain disorder that affects movement, posture, and balance can also affect speech and swallowing
Refers to paralysis or uncontrolled movements due to damage of the brain
Can be developed before birth, during birth, or after birth and can be caused due to lack of oxygen, premature birth, infections, brain hemorrhages, jaundice, and head injury
Most common childhood motor problem
cerebral palsy
damage to the cerebral hemispheres; can occur on one side of the body or just legs or in all four limbs; results in muscle stiffness and rigidity
spastic CP
damage to the basal ganglia resulting in abnormal muscle tone that affects the whole body; muscle tone can change from hour to hour or day-to-day
Dyskinetic CP
this coordination between muscle groups because of cerebellar damage results in clumsy movement and difficulty in walking
ataxic CP
more than one type of motor issue
Mixed CP
probable neurophysiological difference in the brain of those who stutter versus those who do not stutter
stammering
smoothness with which words sounds and sentences flow during oral language
fluency
any interruption in the smoothness
dysfluency
- May be caused due to genetics, environmental factors, possible brain difference [right hemisphere overactive and left hemisphere under active]
stuttering
Neuroplasticity refers to the adaptive capacity of the human brain
The brain is always changing, rewiring itself in response to the internal and external influences
brain plasticity
