COSI 325 Chapter 11: Neuroanatomy

What are the two divisions of the nervous system?

1. CNS

2. PNS

What is the central nervous system?

The central nervous system is made up of the brain and the spinal cord

What is the peripheral nervous system?

Everything else besides the brain and the spinal cord:

• Nerves

• Cranial Nerves

• Tracts

What are the two divisions of the peripheral nervous system?

1. Sensory PNS

2. Motor PNS

What are two divisions of the sensory PNS?

1. Special Sensory

2. General Sensory

What is the special sensory division of the sensory PNS?

• saved for senses that can only be produced in one place

• ex: smell, taste, equilibrium, vision

What are the two divisions of the general sensory division of the PNS?

1. somatic sensory

2. visceral sensory

What is the somatic sensory division of the general sensory?

• more superficial

  • skin

    • pain from temperature

    • feeling vibration

    • proprioception

    • touch

What is the visceral sensory division of the general sensory?

• sensory to deeper structures (deep organs)

  • dull pain: stomach ache

  • discomfort from abdominal distension

  • chest pain

What are the two divisions of the motor sensory division of the PNS?

1. Somatic Motor

   1. voluntary movement

   2. skeletal muscle

2. Autonomic Motor

   1. involuntary movement

   2. smooth muscle

      1. cardiac function

What are the two divisions of the autonomic motor system?

1. Sympathetic

   1. fight or flight response

   2. sweat, elevated HR —> fear responses

2. Parasympathetic

   1. rest and digest

   2. lowers hear rate

BOTH ARE NEEDED FOR SURVIVAL

How does the sympathetic nervous system interact with the somatic motor nervous system?

Sympathetic system brings in information from the environment and then send it out to illicit motor responses —> sympathetic sends message to somatic to voluntarily run when faces with fear

What is another word for hindbrain?

rhombencephalon

What is another word for midbrain?

mesencephalon

what is the deep part of the brain called?

Diencephalon

• core/space inside

what is the superficial part of the brain called?

telencephalon

• space outside

What do the diencephalon and the telencephalon make up?

prosencephalon

What do the diencephalon, telencephalon, and the prosencephalon make up?

cerebrum/forebrain

What are the three parts of the hindbrain?

pons, cerebellum, medulla oblangata

What are neurons?

neurons are the most functional unit of communication in the nervous system.

• contain a cell body and a long body called an axon

• communicate via action potential in cell

• can be:

  • excitatory: makes something happen

  • inhibitory: prevents something from happening

What are the parts of a neuron?

• nucleus

• cell body

• axon

• dendrites

• myelin sheath

• nodes of ranvier

• Axon terminal buttons

Do neurons touch in order to communicate?

No! when neurons communicate they actually do not touch the axon terminals fire a signal to the dendrites

Why is myelin important?

the axon has myelination that allows for communication to move quickly via insulation provided by lipid fat

What do dendrites do?

bring info into the neuron

How to the nodes of ranvier effect the way the message moves down the axon?

when information moves along the axon it hops from node to node to node

• it is not a continuous line

• allows for the axon to send info to other cells dendrites quickly and efficiently

What is a difference between the myelin sheath and the soma (cell body)?

the myelin sheath is white matter —> therefore the axons are white matter

The some is gray matter —→ therefore the bodies are grey matter

What are the two places grey matter is found?

1. cortex

   1. Cerebral Cortex: in our brain/cerebrum (big brain) we have a lot of cell bodies superficially

   2. Cerebellum: cerebellar cortex

2. Nucleus

   1. gray matter surrounded by white matter

   2. within the brain stem there are collections of gray matter called nuclei —> nuclei found in the brain stem are cranial nerve nuclei —> this is where cranial nerves originate to be sent out

   3. nuclei are also found in the diencephalon

What is the pre-synaptic cell?

the Axon terminal

What is the post synaptic cell?

the dendrites

what is the process that occurs between pre and post synaptic cells?

synapse!

what are the 3 places where white matter is found?

1. Tracts

2. commissural fibers

3. Association fivers

what is white matter?

a collection of axons

what is grey matter?

collections of cell bodies

What are the two ways in which tracts move?

tracts move up and down

How do commissural fibers move?

They move from left to right

what are the two types of tracts?

• there are 2 main types of tracts

  • Ascending (Afferent): sensory tracts

  • Descending (efferent): Motor tracts

what do commissural fibers do?

they communicate between the left and right hemispheres

• Ex: Corpus callosum!

How do association fibers communicate?

these fibers communicate anteriorly to posteriorly

What are glial cells?

glial cells are supporting cells to neurons

What are the 3 types of glial cells?

1. Astrocytes

2. oligodendrocytes

3. Schwann cells

What do astrocytes do?

they are responsible for blood and brain barrier and how much of a neurotransmitter gets relayed to other neurons

What do oligodendrocytes do?

these create myelin for the central nervous system

what do Schwann cells do?

these cells create myelin but for the PNS

Are nerves part of the PNS or CNS?

Nerves are cells in the peripheral nervous system!

• they are a collection of white matter

• they take information from the periphery (ex:touch) and move it to the cranial nerves in the central nervous system

what is the composition of the spinal cord in terms of matter?

Spinal Cord

• gray matter is on the inside

• white matter is on the outside

What forms the Cranial Nerve Nuclei?

clumps of grey matter that occur because of the criss crossing of a bunch of pathways

What is the point of decussation and why is it important?

The point of decussation is the point where all these pathways are criss-crossing

It is important that this criss crossing occurs so that the left side controls the right side and vice versa

where is the point of decussation found?

Reticular formation

What happens in the reticular formation that leads to the forming of the cranial nuclei?

because so much is criss-crossing there is white and grey matter that is lost and left just hanging around and this is what forms those cranial nerve nuclei

What are the 3 meninges?

1. Pia Mater → soft and sheared against the brain

2. Arachnoid Mater

3. Dura Mater → hard and thicker than the other layers

what are meninges?

the three membranes (the dura mater, arachnoid, and pia mater) that line the skull and vertebral canal and enclose the brain and spinal cord.

List the organization of meninges and spaces of the brain (inner to outer)

1. Pia mater

   1. subarachnoid space

2. Arachnoid mater

   1. subdural space

3. Dura mater

   1. epidural space

4. Skull

Where are pain receptors located in the brain?

pain receptors come from the dura → brain doesn’t feel any pain

• headaches are pressure on the dura

What is special subarachnoid space?

The subarachnoid space is very vascular (has lots of vessels running through this space. Additionally, cerebral spinal fluid runs through this space providing cushion to the brain.

What are meningiomas?

these are tumors that occur within these spaces (subdural, subarachnoid, epidural)

• Because they are layers outside the brain they are more easily removed

• They are also not typically cancerous

What are some issues than occur within the subdural and epidural spaces?

You can have subdural and epidural hematomas

• these typically are caused by trauma

• it is a collection of blood within that space which places pressure on the brain, which is bad

why is it dangerous for there to be pressure on the brain?

An increase in intracranial pressure is a serious and life-threatening medical problem. The pressure can damage the brain or spinal cord by pressing on important structures and by restricting blood flow into the brain

What happens if cerebral spinal fluid does drain in the way it should?

This leads to hydrocephalus (water on the brain) —> a build up of fluid will start to put pressure on the brain which is dangerous

• burrholes may be done to drill the fluid/blood

What happens if a tear occurs in the arachnoid mater?

These tears usually occur due to trauma

• csf leaks into the subdural space and if this happens it can they start to leak out of our nose

  • this is dangerous bc if csf can get out into the environment bacteria can get into the brain → leads to encephalitis

• lose of csf also leads to decreased cushioning of the brain

what is encephalitis?

infection of the brain

Why are the spaces between the meninges important?

allow for expansion of brain if there is a lot of pressure and it can expand without hurting itself

What is encephalopathy?

• brain disease

• acute brain problem (happens suddenly not like a degenerative disease like dementia)

• Encephalopathy is a change in how your brain functions. You may feel confused, agitated or not like yourself. It can be a temporary disturbance or it could permanently damage your brain. There are many possible causes of encephalopathy, like an infection or an underlying condition. Treatment depends on the cause.

what is metabolic encephalopathy?

Metabolic encephalopathy is a problem in the brain. It is caused by a chemical imbalance in the blood. The imbalance is caused by an illness or organs that are not working as well as they should. It is not caused by a head injury. When the imbalance affects the brain, it can lead to personality changes.

What lobe is in green?

frontal lobe

What lobe is in green?

parietal lobe

What lobe is in green?

temporal lobe

What lobe is in green?

occipital lobe

What lobe is in green?

Insular lobe

What structure is seen in green?

cerebrum (big brain)

What is the section in green called?

frontal pole

What sulcus is in green?

central sulcus

What is the gyrus in green

Precentral gyrus

Which gyrus is in green?

Superior frontal gyrus

Which gyrus is in green?

Middle frontal gyrus

Which gyrus is in green?

Inferior frontal gyrus

Which gyrus is in green?

postcentral gyrus

Which gyrus is in green?

Superior temporal gyrus

Which gyrus is in green?

Middle temporal gyrus

Which gyrus is in green?

Inferior temporal gyrus

which sulcus is in green?

calcarine sulcus

which sulcus is in green?

superior frontal sulcus

which sulcus is in green?

inferior frontal sulcus

What part of the inferior frontal sulcus is in green?

pars opercularis

What part of the inferior frontal sulcus is in green?

pars triangularis

What part of the inferior frontal sulcus is in green?

pars orbitalis

which is the sulcus in green?

superior temporal sulcus

Which is the sulcus in green?

medial temporal sulcus

What structure of the brain is depicted in green?

cerebellum (little brain)

what structure of the brain is depicted in green?

brain stem

which gyrus is in green?

supra-marginal gyrus

which gyrus is in green?

angular gyrus

what structure of the brain stem is this?

pons

what structure of the brain stem is that?

medulla oblangata

What structure is in green?

occipital pole

What is the blue structure called?

silvian fissure

What is the green structure called?

ascending ramus

What is the purple structure called?

horizontal ramus

what is the blue structure called?

posterior ramus

what is the name of the sulcus in blue?

Parietooccipital sulcus

what structure is in blue?

preocciptal notch