Exam 2 Flashcards
What is the Central Nervous System (CNS) protected by?
The skeleton
Where do the cranial nerves come off of?
The brainstem
Where do the spinal nerves come off of?
The spinal cord
What makes up the CNS?
The brain and spinal cord
What makes up the PNS?
Cranial nerves, spinal nerves, and ganglia.
What are the categories of the nervous system divided into?
Sensory nervous system and motor nervous system.
Describe the sensory nervous system.
Contains receptors that transmit information from receptors to the CNS.
Think of this as taking in information and sending it to the brain/spinal cord for processing.
What are the subcategories of the sensory nervous system?
Somatic sensory and visceral sensory.
Describe the somatic sensory system.
Receives sensory information from the skin and special senses. We are consciously aware of these.
Describe the visceral sensory system.
Receives sensory information from viscera (blood vessels and organs). We are NOT consciously aware of this.
Provide two examples of information that the visceral sensory system might receive.
pH levels and oxygen levels.
Describe the motor nervous system.
Transmits information from the CNS to the rest of the body to perform actions. It is sending motor information to effectors.
What are the subcategories of the motor nervous system?
Somatic motor and autonomic motor.
Describe the somatic motor system.
This is our VOLUNTARY motor nervous system in which skeletal muscle is innervated.
Describe the autonomic motor system.
This is our INVOLUNTARY motor nervous system in which cardiac muscle, smooth muscle, and glands are innervated.
What is the metabolic rate for a neuron? As a result, what do they depend on?
Neurons have a high metabolic rate and depend on a constant supply of glucose and oxygen.
T/F: Most of our neurons have a short lifespan.
False! Neurons have extreme longevity in that they stick with us from fetus to elderly age.
T/F: Neurons cannot change, however, they do divide.
False! Neurons CAN change, but CANNOT divide.
How do neurons change?
They can have more or less branching patterns and connections.
Think of the saying “use it or lose it”. This is referring to how we need to use pathways in our brain to strengthen them or we can lose how strong they are.
What do unipolar neurons do?
Carry sensation from the skin.
What do the dendrites in unipolar neurons do?
Sense different types of touch.
Unipolar neurons have a short single process. What is this comprised of?
The short single process is divided into a peripheral process, near where the dendrites are, and a central process, near where the axons are.
In a unipolar neuron, what does the cell body do?
It takes information from the peripheral process, generates a response, and then sends this response to the central process.
What type of neuron is this? Where would we find this?
Unipolar neuron. This is a sensory neuron that can help us sense different types of touch.
T/F: Similar to unipolar neurons, multipolar neurons only have a short single process.
False. Multipolar neurons have multiple processes.
In multipolar neurons, what is the role of dendrites?
They receive and collect information from other neurons and send it towards the cell body.
In multipolar neurons, what is the role of the axon?
Sends information away from the cell body to other neurons.
What is the role of myelin sheath?
It increases the conduction of velocity for action potentials.
What is white matter made up of?
Contains myelinated axons which is why it has a white appearance.
What is gray matter made up of?
Contains the cell bodies of neurons, but does NOT contain myelin, thus, it is gray.
Label the white and gray matter. Also, label the anterior/dorsal and posterior/ventral.
The top part is the dorsal/posterior region and the bottom part is the ventral/anterior region.
Why is it called the posterior root ganglion?
The ganglion resides outside of the posterior/dorsal spinal cord.
T/F: The unipolar cell body resides in the spinal cord.
False! The unipolar cell body is NOT in the spinal cord.
What is a ganglion?
A group of cell bodies outside of the CNS.
Where does afferent information enter the spinal cord?
At the dorsal/posterior horn.
What is the role of the interneuron and where does its cell body reside?
The cell body is in the dorsal horn. The role of the interneuron is to receive sensory info from the dorsal horn, then send it somewhere else.
What is another name for interneurons?
Association neurons
Are interneurons multipolar or unipolar?
Multipolar
If we just wanna know information but do not need to act, what does the interneuron do the information?
Sends it to the brain.
Where is the cell body of the motor neuron?
In the ventral horn
What is the role of the motor neuron?
Sends info to the muscle to address the sensory info.
Where are Glial cells generally found?
Within the CNS and PNS.
How are Glial cells different from neurons?
They are smaller and capable of mitosis, so there is an endless supply of them.
What is the role of Glial cells? What can they NOT do?
Glial cells physically protect and nourish neurons by providing an organized, supporting framework for all the nervous tissue.
They are NOT able to transmit impulses.
What type of cell far outnumbers neurons and accounts for roughly half of the volume of the nervous system?
Glial cells
How many types of Glial cells are there? How many in the CNS? How many in the PNS?
There are 6 types of Glial cells overall.
4 types in the CNS.
2 types in the PNS.
What Glial cells reside in the CNS?
OMEA:
oligodendrocytes, microglial cells, ependymal cells, and astrocytes.
What types of Glial cells reside in the PNS?
SN:
Satellite cells and Neurolemmocytes (Schwann cells)
What are the roles of astrocytes?
1) Provide a structural framework in the CNS
2) Fill in spaces where neurons die
3) Help to form the BBB.
What is the blood-brain-barrier? What is its role?
This controls substances leaving the capillaries and entering the fluid surrounding neurons.
This protects the delicate CNS tissue from toxins while allowing for nutrients to pass through.
What are 3 specializations of the BBB?
1) A continuous basement membrane that surrounds the outsides of cells.
2) Tight junctions that allow for endothelial cells to be tightly bound together.
3) Perivascular feet that cover filtration slits but will relax and move if they want to let something in.
What type of fluid do the ventricles of the brain contain?
Cerebrospinal Fluid (CSF)
What is CSF made up of? What does CSF do?
CSF is made up of extracts of blood plasma that enter the brain cavities.
CSF provides nutrients to spaces deep inside the brain.
What do Ependymal cells do?
They cover capillaries that project within the brain cavities and form a choroid plexus.
What does the choroid plexus produce?
CSF from the blood.
What is a choroid plexus?
Capillaries with ependymal cells surrounding them.
What do Microglial cells do?
They perform phagocytic activity and remove debris from dead or damaged neurons.
What do Oligodendrocytes do?
Their processes attach to nearby axons and wrap the cell membrane around them to form myelin.
What is myelin? What does it do?
A phospholipid bilayer from the cell membrane wrapping around the axons.
This insulates the axons and increases impulse velocity.
How does myelin increase impulse velocity?
It leaves gaps/nodes in between the sheathes along the axon. These nodes are where Na+ can enter in, so there is less space along the axon where Na+ needs to enter into the cell, making it way faster to travel along the axon.
What do Satellite cells do?
They regulate the delivery of nutrients to and removal of waste products from neurons.
Where do satellite cells reside?
They are clustered on the outsides of cell bodies.
What do Neurolemmocytes/Schwann cells do?
They provide myelin (cell membrane) to specific areas and lengths of an axon.
What does the epineurium do?
Protect the nerves and prevent spillover.
What do neurolemmocytes release when neurons are damaged? Is this in both the PNS and CNS?
They release nerve growth factor (NGF). This is only in the PNS, not in the CNS.
What does nerve growth factor do?
It signals the end of the axon still attached to the cell body to regenerate and remyelinate their axon.
Why do we see regeneration of neurons in the PNS, but not in the CNS?
1) In the CNS, astrocytes take the place of dead neurons and this prevents regeneration.
2) Neurolemmocytes are not in the CNS so there is no nerve growth factor that is released into the CNS.
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How do we tell where the head of the neural tube is?
This is the end where the primary vesicles will develop at around week 4.
At what week do the primary vesicles develop in the neural tube?
At week 4
What are primary vesicles?
These are bulges that develop in the neural tube which show the brain starting to develop.
What are the names of the primary vesicles of the neural tube?
Prosecephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain).
What are the names of the secondary vesicles of the neural tube?
Telencephalon, Diencephalon, Mesencephalon, Metencephalon, and Myelencephalon.
What does the prosecephalon differentiate into?
Telencephalon and Diencephalon
What does the Mesencephalon differentiate into?
Mesencephalon
What does the Rhombencephalon differentiate into?
Metencephalon and Myelencephalon
What structures do the Telencephalon and Diencephalon turn into?
Cerebrum, Thalamus, Hypothalamus, and Epithalamus.
What structure does the Mesencephalon turn into?
Midbrain
Remember this as MMM:
Mesencephalon, Mesencephalon, Midbrain.
What structures do the Metencephalon and Myelencephalon turn into?
Pons, Cerebellum, and Medulla Oblongata.
What is a fissure?
Deep groove between gyrus.
What is a gyrus?
These are the wrinkles of the brain.
What is a sulcus?
Grooves between the gyrus.
What is the cortex?
The outer surface of the brain that is comprised of gray matter.
What are cerebral nuclei?
Areas of gray matter embedded within the brain.
Is gray matter generally on the inner or outer surface of the brain?
Outer surface of the brain
Is white matter generally on the inner or outer surface of the brain?
Inner parts of the brain
What are meninges?
Layers that protect the brain
What makes up the dura mater?
The meningeal dura and periosteal dura.
What is the periosteal dura?
Associated/fused with the skull throughout the cranial cavity.
What is meningeal dura? What is an example?
This can peel away from periosteal dura to form specialized structures of the brain.
Ex: The membrane that is between hemispheres protects the brain from excessive side-to-side motion. However, it is not protective for front-to-back motions.
What are dura-venous sinuses?
These are areas where the mater is pulled away and it is filled with venous blood.
What is the arachnoid trabeculae?
String-like attachments to anchor the arachnoid mater to the pia mater.
What are the spaces within the arachnoid trabeculae filled with?
The spaces within are filled with CSF for protection and shock absorption.
What is the role of the pia mater?
Protection of the brain
What does the dural venous / superior sagittal sinus do?
It collects deoxygenated blood from the veins in the brain and drains into the confluences of sinuses to go to the heart.
However, it is NOT a true vein.
What does dura mater translate into?
“Tough mother”
What does arachnoid mater translate into?
“Webber mother”
What does pia mater translate into?
“Delicate mother”
What is the Falx cerebri?
“Sickle-shaped” midline partition that runs between the hemispheres.
What is the Tentorium cerebelli?
A horizontal protective layer for the cerebellum, which resides under the Falx cerebri.
What is the straight sinus?
Receives blood from the inferior sagittal sinus. This is where the falx cerebri meets tentori cerebelli.
Where does the inferior sagittal sinus empty into?
The straight sinus
What does the Great cerebral vein empty into?
The straight sinus
Describe the movement of the right transverse sinus.
Flows forward then down through the sigmoid sinus.
How many ventricles are there in the brain? Name them.
4:
2 lateral ventricles found within the hemispheres
Third ventricle
Fourth ventricle
Where do the 2 lateral ventricles flow into?
Flow into the 3rd ventricle
What is the Mesencephalic/Cerebral aqueduct?
A narrow tube that brings us to the 4th ventricle between the cerebellum and brainstem.
Where is the 4th ventricle located?
Between the brainstem and cerebellum.
Describe the movement of CSF through the central canal of the spinal cord.
Some CSF (very tiny amount) flows down into the central canal of the spinal cord and goes to the sub-arachnoid space.
What do arachnoid villi do?
Allows CSF to be returned into venous blood (CSF’s origin)
What are apertures?
Openings to get into the subarachnoid space.
How do we identify/divide lobes?
We identify the brain lobes by looking at landmark grooves.
T/F: The frontal lobe is responsible for sensory information and the parietal lobe is responsible for motor information.
False!
The frontal lobe is responsible for motor information and the parietal lobe is responsible for sensory information.
What is the precentral gyrus? Where is it located?
Gray matter that controls skeletal muscle on the contralateral side.
It is located in the front lobe anterior to the central sulcus.
What is Broca’s area? Where is it located?
This is the motor speech area of the brain that is responsible for speech production.
This is located in the left hemisphere of the frontal lobe.
What is the postcentral gyrus? Where is it located?
This receives sensation from skin on the contralateral side.
This is located in the parietal lobe just posterior to the central sulcus.
What is Wernicke’s area? Where is it located?
This is the sensory speech area of the brain meaning it is responsible for understanding speech from others.
This is located in the left hemisphere of the parietal lobe.
What is the primary visual cortex? Where is it located?
This area receives info from your eyes so that we can be aware of our visual information.
This is located in the occipital lobe.
What is the primary auditory cortex? Where is it located?
This is responsible for our sense of hearing.
This is located in the temporal bone.
What is the primary olfactory cortex?
This is responsible for our sense of smell.
This is located in the temporal bone.
What is the insula important for? What 3 things does it help with? How early does it develop?
It is important for our survival as it helps with taste, awareness of self, and perception of pain (TAP).
It is one of the 1st areas of the brain to develop.
What is the left hemisphere of the brain generally responsible for? What side of the body does it control?
“Math & Science”
Controls the right side of the body.
What is the right hemisphere of the brain generally responsible for? What side of the body does it control?
“Art & Creativity”
Controls the left side of the body.
What are tracts?
Bundles of axons that connect different parts of the brain and nervous system.
What is the corpus callosum?
Myelinated axons going from the left to right hemisphere.
What do association tracts do?
Interconnect parts of the SAME HEMISPHERE.
What do commissural tracts in the corpus callosum do?
Interconnect parts of the two HEMISPHERES to EACH OTHER.
What do the projection tracts do?
Project down from the hemispheres down to the brain stem and spinal cord.
Where is the thalamus located?
It is embedded deep within the hemispheres at the diencephalon.
What are the 3 major parts of the diencephalon?
Thalamus, hypothalamus, epithalamus.
THE!
What does the thalamus do?
Relays somatosensation to the cerebral cortex.
Basically, the thalamus is deciding what lobe to send incoming information to.
What does the epithalamus do? What is it under the control of?
It has a pineal gland that secretes melatonin. This is controlled by the hypothalamus telling it when to secrete melatonin based on our circadian rhythm.
What does the hypothalamus do?
1) Controls the Autonomic Nervous System (ANS)
2) Controls endocrine system
3) Regulates body temperature
4) Controls emotions
5) Responsible for thirst & hunger
6) Oversees our circadian rhythm
Where is the pituitary gland and what does it do?
It hangs off of the hypothalamus and releases hormones.
What makes up the corpora quadrigemina?
The superior and inferior colliculi.
What does the superior colliculi do?
Tracks objects with our eyes (visual movement).
What does the inferior colliculi do?
Tracks objects based on the sound they’re making.
What are cerebral peduncles?
Contain myelinated axons passing through the brainstem.
What does the substantia nigra contain? What does it do? How does it appear?
Contains dopaminergic neurons that produce Dopamine, which helps with motor control and coordination.
This appears as a dark pigment within them.
How can we attribute Parkinson’s disease to the substantia nigra? How do these appear with Parkinson’s disease?
Degeneration of the dopaminergic neurons in the substantia nigra is associated with Parkinson’s disease.
This area of the brain will appear light instead of dark now.
What parts of the brainstem controls the respiratory center?
Pons and Medulla Oblongata
What part of the brainstem controls cardiac function?
Medulla Oblongata
What is Ataxia? What causes this?
Poor motor control causing jerky movements.
Damage to the cerebellum causes Ataxia.
What does the cerebellum do? Where does it take info from to do so?
It helps us to perform precise and smooth movements/actions.
The cerebellum takes info from the cerebrum, processes it, and works with the cerebrum to make smooth, coordinated movements.
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