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
What is the sympathetic division of the autonomic nervous system?
This division is responsible for the “flight or fight” response activated by the adrenal glands
What is the autonomic nervous system>
Part of the peripheral nervous system that deals with involuntary functions
Where does the name for the autonomic system comes from from?
The Greek word “autonomia” that means “independence”
What is the sympathetic division of the autonomic nervous system?
Responsible for “fight or flight” activated by the adrenal glands
What is the somatic nervous system?
All the axons bring information from/to the tissues to and from the spinal cord. All nerves that bring motor signals to muscles in the face and neck are also part of the somatic nervous system
Is the somatic nervous system under voluntary control?
Yes
What is the peripheral nervous system?
Nerves that relay info. from the brain and the body; divided into the somatic and autonomic nervous system
What are the clusters of cell bodies in the peripheral nervous system called?
Ganglia
What is the choroid plexus?
A spongy material that lines each of the ventricles to produce more CSF
What happens to old CSF?
It is reabsorbed by the body via the meninges in a continuous cycle
True or False? The more microglial the cells the better
False
Where does CSF go after reaching the bottom of the spinal cord?
It joins the fluid in the meninges of the brain (subarachnoid space)
What is the dura matter?
Outermost layer of meninges that is thick and leathery
Dura matter is Latin for. . . ?
“tough mother”
What is the space between the skull and dura matter?
known as the epidural space
What is the purpose of the epidural space?
to soften or absorb shock from a blow to the head as it is made of fats
What is the space below (inside) dura matter?
The arachnoid membrane which features long stringy components
What is the subdural space?
Small space between the arachnoid membrane and dura matter (dangerous if there is blood in it as a result of damage, known as a hematoma)
What is the subarachnoid space?
A larger cavity below the arachnoid membrane that is filled with cerebrospinal fluid to cushion and protect the brain. It also allows the brain to float and give blood vessels access to the brain
Where is the temporal lobe?
Sides of the head near the temple and under each ear
What is the function of the temporal lobe
important for speech, processing auditory sounds, memory, music, and object recognition
Where is the occipital lobe located?
Back of the cerebrum and above the cerebellum
What are the functions of occipital lobe?
processes visual input brought in from the eyes
Where is the parietal lobe located?
Behind the frontal lobe and on top of the head
What are the functions of the parietal lobe?
Processes somatosensation (feeling of touch; pain, temp, pressure, and vibration) and proprioception (sense of knowing where your body is in a space)
What is the prefrontal cortex?
Association area of the frontal lobe in front of the motor cortex that deals with emotion, judgement, cognition, and thinking
Where is the frontal lobe located?
Directly behind the forehead, front of the brain
What is the function of the occipital lobe?
deals with complex thinking and cognition
Where is the motor cortex located?
back of the frontal lobe
What is the cerebral cortex?
outermost layers of the cerebrum (wrinkly layer) aka the grey matter
What are the bumps on the brain called?
Gyrus (plural: gyri)
What are the grooves on the brain called?
Sulcus (plural: sulci)
True or False? The two cerebral hemispheres are symmetrical
true
What is the parasympathetic division?
It is responsible for “rest and digest” (i.e. the body is focused on body maintains) and inhibits the sympathetic division
The brainstem and sacral spinal cord are involved with the ganglia spread throughout the body.
What is the axon hillock?
is where the axon begins and the soma ends
What is the axon terminal?
an axon terminal where the signal is released as a neurotransmitter
What is the synaptic cleft?
space between neurons
What is the function of the pons?
- Its nuclei control facial movement, hearing, chewing muscles, and balance
- Controls semi-voluntary functions
Where is the pons located?
Middle of the brainstem (connecting the medulla and the midbrain- where it’s name that means “bridge” comes from
What is the function of the midbrain?
- Regulates eye movement and pupillary light reflex
- Integrates auditory and visual input to map out the environment
Where is the basal ganglia located?
Center of the cerebral hemisphere near the the thalamus
What is the purpose of the basal ganglia?
its cluster of nuclei help with voluntary movements and prevent unwanted movement
What does the pituitary gland do?
- Release hormones regulating growth
- Control other glands in the endocrine system
What subcortical structure of the brain controls the pituitary gland?
Hypothalamus
What is homeostasis?
refers to keeping the body’s systems in balanced and a healthy state
Where is the hypothalamus located?
Below the thalamus and next to the pituitary gland
What is the purpose of the hypothalamus?
- Regulates critical factors for homeostasis (but it does not perform the actions to do so itself but instructs other organs/structures/glands to do so)
- Mediates the pituitary gland
What is the thalamus and its importance?
- Acts as a relay station for input from the body to the brain (excluding smell)
- Plays a role in motor control, cognition, emotional behavior, and conciousness
What is the importance of the hippocampus?
- Crucial for long term memory and memory consolidation
- Part of the limbic system
Name originates from the mythological sea horse that has the upper body of a sea horse but lower body of a fish
Describe the amygdala
- Found in the temporal lobe and is part of the limbic system
- Comes from the Greek word meaning almond
- Primarily deals with fear, threat, stress, award, and arousel
What is the limbic system?
a group of interconnected structures that deal with memory, learning, and emotion (hypothalamus, amygdala, hippocampus, and the thalamus)
What are subcortical structures?
Regions or structures underneath the cerebral cortex and usually one of each is found on each hemisphere
Where is the cerebellum located?
Underneath the cerebrum
Function of the cerebellum
deals with skill memory and motor system
it has more neurons than the cerebrum
