26- Cerebrum & Cerebellum

cerebrum

-Area of the brain responsible for all voluntary activities of the body

-telencephalon

-diencephalon

telencephalon

what is the cerebral cortex, basal ganglia, limbic system in?

diencephalon

what is the thalamus, hypothalamus, pineal gland in?

brainstem

• oldest part and central core of brain

• begins where spinal cord swells as it enters the skull

• responsible for automatic survival functions

cerebellum

large structure of the hindbrain that controls fine motor skills

spinal cord

Nerves that run up and down the length of the back and transmit most messages between the body and brain

conus medullaris

end of spinal cord

cauda equina

end of spinal cord at L1/L2

rostral

toward the forehead or nose

caudal

posterior or toward the feet

coronal slice

sagittal slice

horizontal slice

multipolar neuron

-most common

-many dendrites extend from soma

-projection and interneurons

projection neuron

a neuron with a very long axon that communicates with neurons in distant areas of the nervous system

interneurons

neurons within the brain and spinal cord that communicate inside and intervene between the sensory inputs and motor outputs

projection and interneurons

Types of multipolar neurons

bipolar neurons

-one axon and one dendrite

-long dendrite to soma

-olfactory and retinal cells

olfactory neuron

part of the nasal mucosa; depolarize in response to odorants in the nasal cavity

retinal cell

• help communicate between photoreceptors and ganglion cells

• alter sensitivity

• major role in adjusting to dim or bright light

• synapse with bipolar cells and bipolar cells synapse with ganglion cells

olfactory and retinal cells

Types of bipolar neurons

pseudounipolar

-The cell body is off to one side of the axon

-two axons

-sensory neurons

sensory neurons

-neurons that carry incoming information from the sensory receptors to the brain and spinal cord

-pseudounipolar neuron

astrocytes, ependymal cells, oligodendrocytes, microglia

Glial cells of the CNS

astrocytes

-maintain blood brain barrier

-controlling levels of neurotransmitter around synapses

-regulate ion and provide metabolic support

ependymal cells

-lines spinal cord & ventricles of the brain

-involved in producing CSF

oligodendrocytes

myelinate CNS axons, provide structural framework

microglia

-brain's immune cells

-remove dead cells and pathogens by phagocytosis

satellite cells and schwann cells

Neuroglial cells of the PNS

satellite cells

-surround neuron cell bodies in PNS

-regulate neurotransmitter levels

Schwann cells

-myelinate neurons in PNS

-maintenance and regeneration of neurons after injury

gray matter

• brain and spinal cord tissue

• consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons

ganglia

clusters of cell bodies in the PNS

nucleus

clusters of cell bodies in the CNS

cortex

surface of the brain or cerebellum that is primarily gray matter

white matter

-nervous tissue of CNS consisting of neurons and their myelin sheaths

-bundles of axons

lipid rich nature of myelin

Why is white matter white?

tract

bundle of axons in the CNS

lemniscus

a tract that meanders through the brain like a ribbon

fasciculus

bundle of muscle fibers

column

• composed of bundles of nerve fibers (axons) that transmit information up and down the spinal cord

• named based on their location relative to the grey matter within the spinal cord

peduncle

a stalk-like structure that connects different parts of the brain

capsule

pathway for nerve fibers connecting the cerebral cortex with other parts of the brain and spinal cord

internal capsule

A large collection of axons that connects the telencephalon with the diencephalon.

lateral ventricle

one of the two ventricles located in the center of the telencephalon

corpus callosum

communication between the two hemispheres

head of caudate nucleus

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

anterior limb of internal capsule

Bounded by the lentiform nucleus and head of the caudate nucleus

-Anterior thalamic radiation; corticopontine

temporal lobe

A region of the cerebral cortex responsible for hearing and language.

internal capsule

A large collection of axons that connects the telencephalon with the diencephalon.

third ventricle

the ventricle located in the center of the diencephalon

caudate nucleus

One of the basal ganglia; it has a long extension or tail.

putamen

large subcortical structure, part of the basal ganglia

globus pallidus

component of the basal ganglia that connects to the thalamus which relays information to the motor areas and the prefrontal cortex

amygdala

two lima bean-sized neural clusters in the limbic system; linked to emotion.

optic chiasm

point at which optic nerve fibers cross in the brain

optic tracts

nerve pathways traveling from the optic chiasm to the thalamus, hypothalamus, and midbrain

substantia nigra

An area of the midbrain that is involved in motor control and contains a large concentration of dopamine-producing neurons

red nucleus

• in midbrain

• receives inputs from the cerebellum and motor cortex

• sends axons to motor neurons in the spinal cord

subthalamic nucleus

a small nucleus, located ventral to the thalamus, that is part of the basal ganglia

thalamus

-relay and process info

-regulate consciousness

hypothalamus

regulate homeostasis, growth, and behaviors

epithalamus (pineal gland)

regulates endocrine system

subthalamus

brain structure that regulates movement

brainstem

-midbrain, pons, medulla

-primarily white matter tracts with nuclei for some cranial nerves

midbrain

-small part of brain above the pons that integrates sensory info and relays it upward

-has cerebral peduncles

cerebral peduncles

contain fibers that carry motor output from cerebrum to other regions of CNS

pons

A brain structure that relays information from the cerebellum to the rest of the brain

medulla

the base of the brainstem; controls heartbeat and breathing

more ascending axons that haven't exited spinal cord

Why is the cervical cord bigger?

has motor neurons for lower extremity

Why is the lumbar cord bigger?

spinal nerves are motor and sensory and cutaneous are sensory only; cutaneous are branches of spinal nerves

What is the difference between spinal nerves and cutaneous nerves?

cranial nerves

12 pairs of nerves that carry messages to and from the brain

spinal nerves

31 pairs of nerves arising from the spinal cord

spinal roots

a bundle of axons surrounded by connective tissue that occurs in pairs, which fuse and form a spinal nerve

cutaneous nerves

Nerves that go into skin, giving off terminal branches that ascent into dermi

"Only one of the two athletes felt very good, victorious, and healthy"

How to remember cranial nerves

olfactory nerve (CN I)

Responsible for the sense of smell.

optic nerve (CN II)

sensory, vision

oculomotor nerve (CN III)

Controls eye movement and pupil constriction.

trochlear nerve (CN IV)

innervates the superior oblique muscle

trigeminal nerve (CN V)

• somatic sensory nerve to skin over mandible, temporal region, and anterior 2/3 of the tongue

• sensitive to texture/irritants on the tongue and in the nasal cavity/eye

• lingual nerve is the branch that controls touch for the tongue

abducens nerve (CN VI)

Innervates the lateral rectus muscle of the eye

facial nerve (CN VII)

innervates muscles of facial expression

vestibulocochlear nerve (CN VIII)

Responsible for hearing and balance.

glossopharyngeal nerve (CN IX)

general sensation and taste: posterior 1/3

vagus nerve (CN X)

nerve that passes through jugular foramen

accessory nerve (CN XI)

Innervates sternocleidomastoid and trapezius muscles.

hypoglossal nerve (CN XII)

tongue movement

31; 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

How many spinal nerves are there and how many of each type?

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

brainstem and sacral spinal cord

Where does the parasympathetic nervous system come from?

sympathetic nervous system

-the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

-fight or flight

T1-T12

Where does the sympathetic nervous system come from?

frontal lobe

A region of the cerebral cortex that has specialized areas for movement, abstract thinking, planning, memory, and judgement

parietal lobe

region of the cerebral cortex whose functions include processing info about touch

occipital lobe

vision

sylvian fissure

Also called lateral sulcus. A deep fissure that demarcates the temporal lobe.

cerebellum

-A large structure of the hindbrain that controls fine motor skills.

-balance and coordination

dura mater

thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord