Brain and Spinal Cord Flashcards
Consists of the brain and spinal cord.
These control everything you do, feel, and think.
Central nervous system (CNS)
Divided into two cerebral hemispheres (left and right), the largest part of the brain.
Cerebral hemisphere
Located above the brainstem, contains the thalamus and hypothalamus.
Diencephalon
Connects the brain to the spinal cord and controls basic life functions.
Brain stem
Coordinates balance, muscle tone,
and voluntary movements.
Cerebellum
4 main parts of the brain
cerebrum, diencephalon, brain stem, cerebellum
Ridges of the brain
Gyrus (Plural: Gyri)
Grooves of the brain
Sulci
Deep grooves of the brain
Fissures
The outermost layer of gray matter
making up the superficial aspect of the cerebrum
Cerebral cortex
Superficial gray matter.
Cortex
Deep in the cortex, consisting of myelinated axons.
White matter
Pockets of gray matter within the white matter that regulate voluntary motor activities by altering primary motor cortex instructions.
Basal nuclei
Where are motor areas located?
Frontal lobe
→ Controls voluntary movements of skeletal muscles.
→ Sends signals to muscles to initiate movement.
Motor areas
→ Found in the left frontal lobe (typically).
→ Responsible for the production of
speech (language output).
→ Damage can result in Broca’s aphasia, affecting speech production but not comprehension.
Broca’s area
○ Primary Somatosensory Area
→ Located in the Parietal Lobe, specifically in the postcentral gyrus.
→ Processes sensory information from the body (touch, pain, temperature,
etc.).
→ Receives signals from sensory receptors in the skin and muscles.
Sensory areas
Where are sensory areas located?
Parietal lobe
→ Located in the left temporal lobe (typically).
→ Responsible for understanding speech (language comprehension).
→ Damage can result in Wernicke’s aphasia, affecting comprehension but not speech production.
Wernicke’s area
loss of ability to understand or express speech, caused by brain damage
Aphasia
More neurons are dedicated to areas with finer motor control, like the hands and face.
Motor map
Neurons are mapped to areas with higher sensory sensitivity, such as the hands and lips.
Sensory map
→ Islands” of gray matter buried deep
within the white matter of the
cerebrum
→ Regulate voluntary motor activities
by modifying instructions sent to skeletal muscles by the primary motor cortex
Basal nuclei
→ Sits on top of the brain stem
→ Enclosed by the cerebral hemispheres
Diencephalon
3 structures of diencephalon
Thalamus, hypothalamus, epithalamus
→ Encloses the third ventricle
→ Functions as a relay station for
sensory impulses, directing them to the appropriate cortex areas for localization and interpretation.
Thalamus
→ Important autonomic nervous
system center
■ Regulates body temperature ■ Regulates water balance
■ Regulates metabolism
→ Houses the limbic center for emotions
→ Controls the pituitary gland, a crucial endocrine gland, through the infundibular stalk, affecting hormone release.
→ Houses mammillary bodies
Hypothalamus
→ Forms the roof of the third ventricle
→ Houses the pineal body (an endocrine gland)
→ Includes the choroid plexus which
forms cerebrospinal fluid for brain and spinal cord protection.
Epithalamus
Responsible for olfaction and associating those things to past experiences and emotional responses.
Mammillary bodies
Attaches to the spinal cord
brain stem
Parts of the brain stem
Midbrain, pons, medulla oblongata
Regulates the general body movements.
Substantia nigra
→ Smallest portion of the brain stem.
→ Dorsally located to that area are the
four colliculi/corpora quadrigemina
(hearing and balance)
→ Auditory and visual reflex center
→ Anteriorly located will be the cerebral
peduncles (little feet) for impulse
transmission
→ With a black mass known as
substantia nigra which regulates the general body movements.
Midbrain
“Bridge” because it connects the
cerebellum and cerebrum. It is located above the medulla and regulates breathing, chewing, swallowing, salivation and balance.
Pons
Prominent enlargements anterior to the medulla. It is involved in the voluntary control of the skeletal muscles
Pyramids
→ The most inferior part of the brain stem that merges into the spinal cord
→ Contains important centers that control:
■ Heart rate
■ Blood pressure
■ Breathing
■ Swallowing
■ Vomiting
Medulla oblongata
→ Diffuse mass of gray matter along
the brain stem
→ Responsible for cyclical motor
functions (walking, chewing) and
control over the internal organs.
→ It forms the Reticular activating
system (RAS)
Reticular formation
■ Plays a role in awake/sleep cycles and consciousness
■ Filter for incoming sensory information
Reticular activating system (RAS)
→ Structure: A cauliflower-like mass with gyri (elevations) and sulci (grooves).
→ Function: Responsible for balance, muscle tone, coordinated movement, and learning motor skills (e.g., playing an instrument).
Cerebellum
Alcohol affects the cerebellum, impairing motor coordination. Damage to the cerebellum results in _____, causing clumsy, drunken-like movements.
Ataxia
The CNS is protected by
Meninges, CSF, Blood-brain barrier
This is a selective semi-permeable membrane between the blood and the interstitium of the brain, allowing cerebral blood vessels to regulate molecule and ion movement between the blood and the brain.
Blood brain barrier
Protective membranes surrounding the brain and spinal cord.
Meninges
→ Outermost leathery layer
→ Double-layered external covering
Dura matter
attached to inner surface of the skull
Periosteum
Outer covering of the brain
Meningeal layer
→ Middle layer
→ Weblike extensions span the subarachnoid space to attach it to the pia mater
→ Subarachnoid space is filled with cerebrospinal fluid
Arachnoid layer
→ Internal layer
→ Clings to the surface of the brain and spinal cord
Pia mater
→ Similar to blood plasma in composition
→ forms a watery cushion to protect the brain and spinal cord
→ It circulates in the arachnoid space, ventricles, and central canal of the spinal cord. It is produced by the choroid plexus and absorbed into the venous blood via arachnoid granulations
Cerebrospinal fluid
CSF is produced by
Choroid plexus
Structure: Extends from the foramen magnum to the first or second lumbar vertebra. It consists of a central gray matter (shaped like a butterfly) and peripheral white matter.
Spinal cord
collection of spinal nerves at the inferior end
Cauda equina
how many spinal nerves arise form the spinal chord?
31 pairs
Contain sensory and association
neurons entering via the dorsal root.
Dorsal/posterior horns
→ Two anterior projections with cell bodies of motor and association neurons that leave the ventral root.
→ Together, the dorsal and ventral root,
will form the spinal nerves
→ Damaged to the ventral root will
result to flaccid paralysis, the impulses cannot go to the effectors because it cannot go out of the spinal cord
Ventral/Anterior horns
Contains myelinated fiber tracts
White matter
White matter is divided into two columns/funiculi:
Posterior column and lateral and anterior column
Carries ascending sensory tracts
(afferent) to the brain.
Posterior column
Contain both ascending (sensory) and descending (motor) tracts carrying impulses to and from the brain.
Lateral and anterior columns
