Science Section 1 Flashcards
Why are microglial cells critical to the nervous system?
They are the central nervous system’s only immune cells ( as a result of it being isolated by the BBB) to fight off infection
What is the function of Schwann cells and oligodendrocytes?
They both myelinate the axons of neurons as glial cells
What is the difference between oligodendrocytes and Schwann cells?
Oligodendrocytes myelinate axons of the CNS while Schwann cells myelinate axons of the PNS
How do astrocyte glial cells regulate the extracellular fluid in between cells in the nervous system?
As the most common glial cells, astrocytes remove the signaling molecules and keep a balance of ions.
What is the blood brain barrier?
Partly formed by astrocytes, the blood brain barrier (BBB) keeps certain substances from entering the brain and potentially damaging the neurons.
How does the restriction of the blood brain barrier affect the brain?
- Keeps the brain healthy
- Much more difficult to deliver drugs to help treat diseases
- Nutrients have less across to the nourish the brain
What is the function of the axon?
Used for transmitting output signals from one neuron to another or a muscle. No organelles in the axon.
What is the myelin and its function?
Myelin is a fatty substance made by glial cells that is meant to insulate the axon for faster and more efficient transmitting output signals
What is the function of the medulla (oblongata)?
Its nuclei relay touch sensation from the face, hearing, balance, swallowing food, vomiting, and other critical functions
-Has a rectangular shape
What is the brainstem?
The “stalk” at the bottom of the brain that connects the rest of the brain to the spinal cord. Most of the nuclei it has controls breathing, heart rate, reflexes, and coordination. Directly underneath the thalamus. Includes three subdivisions; medulla, pons, and the midbrain.
Describe the spinal cord
- Encased in vertebrae (back bone)
- White matter is on the outside of the cord, with grey matter on the inside
- Divided into sections
- Nerves run in between each vertebrae
True or False? The brain stem only consists of grey matter hence its nuclei.
False. Axons entering or exiting the brain must pass through the brainstem. That means there is white matter (myelinated axons) along with clusters of nuclei (grey matter)
What are the sections of the spinal cord?
Cervical, thoracic, lumbar, sacral (top to bottom)
What is the cervical spinal cord meant to control?
innervates with the amrs, neck, and shoulders
Thoracic spinal cord
deals with the chest and torso
Lumbar spinal cord
innervates with the hips and front of the legs
Sacral spinal cord
innervates with the buttocks and back legs
What is the ventricular system?
a series of interconnected cavities or hollow hole (ventricles) in the central nervous system that is filled cerebrospinal fluid (CSF)
What is the lateral ventricle?
A large CSF filled cavity located on both of the cerebral hemisphere near the left and right thalamus at the third ventricle which connects the two lateral ventricles (it’s located at the midbrain)
What connects the third and fourth ventricle?
The cerebral aqueduct is a narrow cavity in the midbrain of the brain stem that connects the third and fourth ventricle (located in the pons and medulla)
Where is the CSF located in the spinal cord?
In the central canal which is a narrow tube in the middle of the cord
What is the difference between glial cells and nerves?
Glial cells are non-neuronal cells and can be reproduced throughout the life of an organism thorugh mitosis
How does a neuron receive synaptic input from other neurons?
Through the dendrites.
This ability does depend on the shape/size of the dendrites.
What language does the word “dendrites” originate from?
Comes from the Greek word for “treelike”
True or False? Neurons are easily replaceable
False. Most neurons are stuck in G0 phase of mitosis
What organelles are located in the soma (cell body) of a neuron?
Nucleus, Golgi apparatus, endoplasmic reticulum, and mitochondria. They are surrounded by cytosol and are separated from the outside by the neuronal membrane.
How do microglial cells fight off infection in the CNS?
They target pathogens and dead/damaged neurons by ingesting or destroying them
True or False? The more active microglial cells there are, the better
False. Hyper-activated microglial cells can cause inflammation in the brain and may lead to Alzeheimer’s
What is the meninges of the CNS?
The three layers of membrane that surround the brain and spinal cord to further protect and separate it from the bone.
What are the gaps in the myelin known as?
Nodes of Ranvier
Purpose of Nodes of Ranvier
allow the axon access to fluid outside the cell (important for sending signals)
What is an interneuron?
Neurons that connect other neurons to one another. They are small w/out long axons
What is the difference between grey matter and white matter?
Grey matter consists of the somas and dendritic arbors of the neurons. While white matter is the myelinated axon
Where is the grey matter and white matter located in the CNS?
Grey matter is located on the outside of the brain (cerebral cortex) with the white matter on the inside. This is the opposite in the spinal cord
What are glial cells?
non-neuronal cells found in the nervous system
What is the sympathetic chain?
A specialized chain of ganglia located next to the spine that sends info. to the body about stress and danger