Exam 2 Flashcards
(402 cards)
1
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What is the Central Nervous System (CNS) protected by?
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The skeleton
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Where do the cranial nerves come off of?
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The brainstem
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Where do the spinal nerves come off of?
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The spinal cord
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What makes up the CNS?
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The brain and spinal cord
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What makes up the PNS?
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Cranial nerves, spinal nerves, and ganglia.
6
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What are the categories of the nervous system divided into?
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Sensory nervous system and motor nervous system.
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Describe the sensory nervous system.
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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.
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What are the subcategories of the sensory nervous system?
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Somatic sensory and visceral sensory.
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Describe the somatic sensory system.
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Receives sensory information from the skin and special senses. We are consciously aware of these.
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Describe the visceral sensory system.
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Receives sensory information from viscera (blood vessels and organs). We are NOT consciously aware of this.
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Provide two examples of information that the visceral sensory system might receive.
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pH levels and oxygen levels.
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Describe the motor nervous system.
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Transmits information from the CNS to the rest of the body to perform actions. It is sending motor information to effectors.
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What are the subcategories of the motor nervous system?
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Somatic motor and autonomic motor.
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Describe the somatic motor system.
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This is our VOLUNTARY motor nervous system in which skeletal muscle is innervated.
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Describe the autonomic motor system.
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This is our INVOLUNTARY motor nervous system in which cardiac muscle, smooth muscle, and glands are innervated.
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What is the metabolic rate for a neuron? As a result, what do they depend on?
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Neurons have a high metabolic rate and depend on a constant supply of glucose and oxygen.
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T/F: Most of our neurons have a short lifespan.
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False! Neurons have extreme longevity in that they stick with us from fetus to elderly age.
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T/F: Neurons cannot change, however, they do divide.
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False! Neurons CAN change, but CANNOT divide.
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How do neurons change?
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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.
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What do unipolar neurons do?
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Carry sensation from the skin.
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What do the dendrites in unipolar neurons do?
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Sense different types of touch.
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Unipolar neurons have a short single process. What is this comprised of?
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The short single process is divided into a peripheral process, near where the dendrites are, and a central process, near where the axons are.
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In a unipolar neuron, what does the cell body do?
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It takes information from the peripheral process, generates a response, and then sends this response to the central process.
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What type of neuron is this? Where would we find this?
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Unipolar neuron. This is a sensory neuron that can help us sense different types of touch.
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T/F: Similar to unipolar neurons, multipolar neurons only have a short single process.
False. Multipolar neurons have multiple processes.
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In multipolar neurons, what is the role of dendrites?
They receive and collect information from other neurons and send it towards the cell body.
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In multipolar neurons, what is the role of the axon?
Sends information away from the cell body to other neurons.
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What is the role of myelin sheath?
It increases the conduction of velocity for action potentials.
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What is white matter made up of?
Contains myelinated axons which is why it has a white appearance.
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What is gray matter made up of?
Contains the cell bodies of neurons, but does NOT contain myelin, thus, it is gray.
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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.
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Why is it called the posterior root ganglion?
The ganglion resides outside of the posterior/dorsal spinal cord.
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T/F: The unipolar cell body resides in the spinal cord.
False! The unipolar cell body is NOT in the spinal cord.
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What is a ganglion?
A group of cell bodies outside of the CNS.
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Where does afferent information enter the spinal cord?
At the dorsal/posterior horn.
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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.
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What is another name for interneurons?
Association neurons
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Are interneurons multipolar or unipolar?
Multipolar
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If we just wanna know information but do not need to act, what does the interneuron do the information?
Sends it to the brain.
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Where is the cell body of the motor neuron?
In the ventral horn
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What is the role of the motor neuron?
Sends info to the muscle to address the sensory info.
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Where are Glial cells generally found?
Within the CNS and PNS.
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How are Glial cells different from neurons?
They are smaller and capable of mitosis, so there is an endless supply of them.
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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.
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What type of cell far outnumbers neurons and accounts for roughly half of the volume of the nervous system?
Glial cells
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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.
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What Glial cells reside in the CNS?
OMEA:
oligodendrocytes, microglial cells, ependymal cells, and astrocytes.
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What types of Glial cells reside in the PNS?
SN:
Satellite cells and Neurolemmocytes (Schwann cells)
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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.
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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.
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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.
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What type of fluid do the ventricles of the brain contain?
Cerebrospinal Fluid (CSF)
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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.
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What do Ependymal cells do?
They cover capillaries that project within the brain cavities and form a choroid plexus.
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What does the choroid plexus produce?
CSF from the blood.
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What is a choroid plexus?
Capillaries with ependymal cells surrounding them.
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What do Microglial cells do?
They perform phagocytic activity and remove debris from dead or damaged neurons.
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What do Oligodendrocytes do?
Their processes attach to nearby axons and wrap the cell membrane around them to form myelin.
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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.
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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.
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What do Satellite cells do?
They regulate the delivery of nutrients to and removal of waste products from neurons.
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Where do satellite cells reside?
They are clustered on the outsides of cell bodies.
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What do Neurolemmocytes/Schwann cells do?
They provide myelin (cell membrane) to specific areas and lengths of an axon.
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What does the epineurium do?
Protect the nerves and prevent spillover.
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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.
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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.
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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.
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At what week do the primary vesicles develop in the neural tube?
At week 4
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What are primary vesicles?
These are bulges that develop in the neural tube which show the brain starting to develop.
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What are the names of the primary vesicles of the neural tube?
Prosecephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain).
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What are the names of the secondary vesicles of the neural tube?
Telencephalon, Diencephalon, Mesencephalon, Metencephalon, and Myelencephalon.
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What does the prosecephalon differentiate into?
Telencephalon and Diencephalon
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What does the Mesencephalon differentiate into?
Mesencephalon
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What does the Rhombencephalon differentiate into?
Metencephalon and Myelencephalon
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What structures do the Telencephalon and Diencephalon turn into?
Cerebrum, Thalamus, Hypothalamus, and Epithalamus.
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What structure does the Mesencephalon turn into?
Midbrain
Remember this as MMM:
Mesencephalon, Mesencephalon, Midbrain.
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What structures do the Metencephalon and Myelencephalon turn into?
Pons, Cerebellum, and Medulla Oblongata.
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What is a fissure?
Deep groove between gyrus.
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What is a gyrus?
These are the wrinkles of the brain.
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What is a sulcus?
Grooves between the gyrus.
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What is the cortex?
The outer surface of the brain that is comprised of gray matter.
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What are cerebral nuclei?
Areas of gray matter embedded within the brain.
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Is gray matter generally on the inner or outer surface of the brain?
Outer surface of the brain
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Is white matter generally on the inner or outer surface of the brain?
Inner parts of the brain
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What are meninges?
Layers that protect the brain
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What makes up the dura mater?
The meningeal dura and periosteal dura.
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What is the periosteal dura?
Associated/fused with the skull throughout the cranial cavity.
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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.
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What are dura-venous sinuses?
These are areas where the mater is pulled away and it is filled with venous blood.
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What is the arachnoid trabeculae?
String-like attachments to anchor the arachnoid mater to the pia mater.
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What are the spaces within the arachnoid trabeculae filled with?
The spaces within are filled with CSF for protection and shock absorption.
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What is the role of the pia mater?
Protection of the brain
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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.
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What does dura mater translate into?
"Tough mother"
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What does arachnoid mater translate into?
"Webber mother"
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What does pia mater translate into?
"Delicate mother"
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What is the Falx cerebri?
"Sickle-shaped" midline partition that runs between the hemispheres.
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What is the Tentorium cerebelli?
A horizontal protective layer for the cerebellum, which resides under the Falx cerebri.
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What is the straight sinus?
Receives blood from the inferior sagittal sinus. This is where the falx cerebri meets tentori cerebelli.
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Where does the inferior sagittal sinus empty into?
The straight sinus
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What does the Great cerebral vein empty into?
The straight sinus
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Describe the movement of the right transverse sinus.
Flows forward then down through the sigmoid sinus.
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How many ventricles are there in the brain? Name them.
4:
2 lateral ventricles found within the hemispheres
Third ventricle
Fourth ventricle
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Where do the 2 lateral ventricles flow into?
Flow into the 3rd ventricle
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What is the Mesencephalic/Cerebral aqueduct?
A narrow tube that brings us to the 4th ventricle between the cerebellum and brainstem.
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Where is the 4th ventricle located?
Between the brainstem and cerebellum.
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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.
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What do arachnoid villi do?
Allows CSF to be returned into venous blood (CSF's origin)
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What are apertures?
Openings to get into the subarachnoid space.
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How do we identify/divide lobes?
We identify the brain lobes by looking at landmark grooves.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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What is the primary olfactory cortex?
This is responsible for our sense of smell.
This is located in the temporal bone.
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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.
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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.
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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.
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What are tracts?
Bundles of axons that connect different parts of the brain and nervous system.
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What is the corpus callosum?
Myelinated axons going from the left to right hemisphere.
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What do association tracts do?
Interconnect parts of the SAME HEMISPHERE.
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What do commissural tracts in the corpus callosum do?
Interconnect parts of the two HEMISPHERES to EACH OTHER.
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What do the projection tracts do?
Project down from the hemispheres down to the brain stem and spinal cord.
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Where is the thalamus located?
It is embedded deep within the hemispheres at the diencephalon.
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What are the 3 major parts of the diencephalon?
Thalamus, hypothalamus, epithalamus.
THE!
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What does the thalamus do?
Relays somatosensation to the cerebral cortex.
Basically, the thalamus is deciding what lobe to send incoming information to.
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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.
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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
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Where is the pituitary gland and what does it do?
It hangs off of the hypothalamus and releases hormones.
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What makes up the corpora quadrigemina?
The superior and inferior colliculi.
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What does the superior colliculi do?
Tracks objects with our eyes (visual movement).
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What does the inferior colliculi do?
Tracks objects based on the sound they're making.
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What are cerebral peduncles?
Contain myelinated axons passing through the brainstem.
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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.
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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.
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What parts of the brainstem controls the respiratory center?
Pons and Medulla Oblongata
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What part of the brainstem controls cardiac function?
Medulla Oblongata
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What is Ataxia? What causes this?
Poor motor control causing jerky movements.
Damage to the cerebellum causes Ataxia.
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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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How many cranial nerves are there?
12
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What is the analogy for remembering the names of the cranial nerves?
Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly
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Name CN I (1). M or S?
Olfactory Nerve. Sensory.
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Name CN II (2). M or S?
Optic Nerve, Sensory
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Name CN III (3). M or S?
Oculomotor Nerve, Motor
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Name CN IV (4). M or S?
Trochlear Nerve, Motor
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Name CN V (5). M or S?
Trigeminal Nerve, Both motor and sensory
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Name CN VI (6). M or S?
Abducens Nerve, Motor
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Name CN VII (7). M or S?
Facial Nerve, both motor and sensory.
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Name CN VIII (8). M or S?
Vestibulocochlear Nerve, Sensory
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Name CN IX (9). M or S?
Glossopharyngeal Nerve, both motor and sensory
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Name CN X (10). M or S?
Vagus Nerve, both sensory and motor.
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Name CN XI (11). M or S?
Accessory Nerve, Motor
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Name CN XII (12). M or S?
Hypoglossal Nerve, Motor
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What is the analogy for remembering sensory versus motor function for cranial nerves?
Some Say Marry Money But My Brother Says Big Business Makes Money
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What cranial nerve passes through the olfactory foramina?
CN I
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What cranial nerve passes through the optic canal?
CN II
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What cranial nerves pass through the superior orbital fissure?
CN III, IV, V1, VI.
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What cranial nerve passes through the foramen rotundum?
CN V2
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What cranial nerve passes through the foramen ovale?
V3
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What cranial nerve passes through the internal auditory meatus?
CN VII and VIII
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What cranial nerve passes through the jugular foramen?
CN IX, X, XI
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What cranial nerve passes through the hypoglossal foramen?
CN XII
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CN1:
Function
Location of receptors
Pathway through skull
Function: Smell
Location of receptors: Roof of nasal cavity
Pathway through skull: Cribriform plate of ethmoid bone
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CN2:
Function
Location of receptors
Pathway through skull
Function: Vision
Location of receptors: Retina of eye
Pathway through skull: Optic foramen
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How do we get binocular vision?
Each optic nerve presents info to both sides of the brain, allowing for binocular vision.
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Name the 6 muscles of the eye
Superior rectus, lateral rectus, inferior rectus, superior oblique, inferior oblique, and levator palpebrae superioris
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Describe the attachment of the oblique eye muscles.
They attach to the eyeball at an angle.
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Describe the attachment of the levator palpebrae superioris.
It attaches to the upper eyelid to open the eye.
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What do cranial nerves do in regards to the eye muscles?
The cranial nerves help to move the muscles of the eye.
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What direction does the inferior oblique move the eye?
Up & out
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What direction does the superior rectus move the eye?
Up & in
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What direction does the lateral rectus move the eye? What CN controls this?
Outward/abduction movement
CN VI performs this abducens.
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What direction does the medial rectus move the eye?
Medially towards the nose
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What direction does the superior oblique move the eye? What nerve controls this?
Down & out "Sad Loser!"
CN IV (trochlear)
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What direction does the inferior rectus move the eye?
Down & in
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What is the equation we can use to remember which CNs innervate which muscles of the eyes?
SO4LR6 / 3
This means that the superior oblique is innervated by CN IV. Lateral rectus is by CN VI. Every other muscle of the eye is CN III.
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How do cranial nerves get to the orbit to innervate the muscles of the eye?
Through the superior orbital fissure
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What type of nerve is the oculomotor nerve?
A motor-only cranial nerve.
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What does the trochlear nerve (CN IV) innervate?
Superior oblique eye muscle
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What does the abducens nerve (CN VI) innvervate?
The lateral rectus eye muscle
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CN5 Division 1:
Functions
Location of receptors
Pathway through skull
Function: Sensation of skin of face and sensation from cornea.
Location of receptor: Opthalmic branch
Pathway through skull: Superior orbital fissure
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CN5 Division 2:
Functions
Location of receptors
Pathway through skull
Function: Sensation of skin of face, sensation from upper teeth.
Location of receptors: Maxillary branch
Pathway through skull: Foramen rotundum
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CN5 Division 3:
Functions
Location of receptors
Pathway through skull
Function: Sensation of skin of face, sensation from lower teeth, sensation from tongue, and somatic motor to muscles of mastification.
Location of receptors: Mandibular branch
Pathway through skull: Foramen ovale
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What is special about sensation from the tongue for CN V3?
It contains both touch (general sensation) and taste (special sensation).
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What is special about the mandibular branch of CN V3?
It has both sensory and motor function.
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What do salivary glands do?
They initiate the breakdown of food in the mouth.
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Name the 3 salivary glands.
Parotid, sublingual, and submandibular (PSS).
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CN VII:
Function (think of the story about eating really good food)
Pathway through skull
Functions:
-Taste from tongue (put the food on your tongue)
-Motor to submandibular and sublingual salivary glands (salivate when you eat)
-Motor to muscles of facial expression (make the 'this is really yummy' face)
-Motor to lacrimal gland (cry cuz its so good)
Pathway through skull: Internal auditory meatus
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CN VIII:
Function
Location of receptors
Pathway through skull
Function: Special sense of hearing and balance.
Location of receptors: Temporal lobe
Pathway through skull: Internal auditory meatus
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Is the vestibulocochlear nerve (CN VIII) sensory or motor?
It is sensory only
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CN IX:
Functions
Location of receptors
Pathway through skull
Functions:
-Motor to parotid gland
-General sensation (touch) and taste from tongue
Location of receptors: Posterior tongue
Pathway through skull: Jugular foramen
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CN X:
Functions
Pathway through skull
Functions:
-Motor to muscles of pharynx and larynx
-Sensation from larynx and pharynx
-Motor to heart, bronchi, and muscles of digestive tract
Pathway through skull: Jugular foramen
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CN XI:
Function
Pathway through skull
Function:
-Somatic motor to trapezius and sternocleidomastoid
Pathway through skull: Jugular foramen
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Describe the special pathway of the accessory nerve.
It originates from the upper cervical spinal cord. Then, it enters the skull through foramen magnum before exiting through jugular foramen.
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What is it odd about the origin of the accessory nerve? Is it still considered a cranial nerve?
It originates from the upper cervical spinal cord.
We generally think of cranial nerves originating from the brain stem, not the spinal cord. However, it is still a cranial nerve.
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CN XII:
Function
Pathway through skull
Function: Somatic motor to muscles of the tongue.
Pathway through skull: Hypoglossal foramen
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Where do unipolar neurons travel to and from?
From the skin to the spinal cord.
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Where do multipolar neurons travel to and from?
From the spinal cord to muscles/effectirs.
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What are sensory/afferent neurons?
Receptors for touch, pressure, pain, vision, hearing, balance, taste, and smells.
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Where are sensory/afferent neurons' cell bodies?
In posterior root ganglion
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What do central processes of the sensory/afferent neurons do?
They carry sensation to the CNS.
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What do interneurons/association neurons do?
Receive impulses from sensory neurons and "decide" what to do with it.
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Who do interneurons facilitate communication between?
Sensory and motor neurons
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What do motor/efferent neurons do? Where are their cell bodies?
Their axons carry impulses to muscles and glands (effectors).
Their cell bodies are in the CNS.
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What types of fiber do spinal nerves contain?
Both sensory and motor fibers, thus, they are said to be mixed.
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Where does sensation come into the posterior spinal cord?
Dorsal root
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Where does info leave the anterior spinal cord?
Ventral root
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What is a spinal cord segment?
A part/length of spinal cord with a pair of spinal nerves attached to it.
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T/F: There is just a single branch of attachment for spinal cord segments.
False. There are multiple branches of attachment for spinal cord segments.
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Which spinal cord meninge is attached to the surface of the spinal cord?
Pia mater
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Which spinal cord meninge is the thick outer layer?
Dura mater
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Which spinal cord meninge is loose around the spinal cord with subarachnoid space containing CSF?
Arachnoid mater
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What passes through the intervertebral foramina?
Spinal nerves
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How many pairs of spinal nerves does the cervical region have?
8 pairs.
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What provides most of the innervation to the upper extremities?
The cervical region
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How many pairs of spinal nerves does the thoracic region have?
12 pairs
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How many pairs of spinal nerves does the lumbar region have?
5 pairs
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What provides most of the innervation of the lower extremities?
Lumbar region
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How many pairs of spinal nerves does the sacral region have?
5 pairs
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What contributes to, but does not provide majority of innervation to the lower extremities?
Sacral region
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How many pairs of spinal nerves does the coccygeal region have?
1 pair
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What provides sensation around the anus?
Coccygeal region
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What is the Conus medullaris?
Marks the inferior end of the spinal cord between L1 and L2 vertebrae.
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What is the Cauda equina?
A "horse's tail" being comprised of nerve roots from the inferior end of the spinal cord.
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What happens to the vertebral column and spinal nerves as we develop?
The vertebral column continues to lengthen causing the spinal nerves traveling through the intervertebral foramina to get stretched out.
257
What is filum terminale?
An extension of pia mater off conus medullaris.
258
Is the brain involved in reflexes?
No!
259
What is a monosynaptic reflex?
Direct communication between sensory and motor neuron.
This is the FASTEST reflex in response to a quick stretch in skeletal muscles.
260
Are interneurons present in a monosynpatic reflex?
NO INTERNEURONS
261
How do we activate the muscle being stretched in a monosynaptic reflex?
By tapping the tendons of the muscle. Think of the knee-jerk reflex.
262
What is a polysynaptic reflex?
An interneuron facilitates sensory-motor communication.
263
What initiates a polysynaptic reflex?
A painful stimulus
264
What is the role of the interneuron in the polysynaptic reflex?
It receives info and relays it to as many motor neurons in the spinal cord as it takes to remove us from the painful stimuli.
265
T/F: Just one muscle is involved in the polysynaptic reflex.
False! Many muscles are involved in the polysynaptic reflex.
266
T/F: The polysynaptic reflex just sends info to one side of the body.
False! The polysynaptic reflex sends info to both sides of the body.
Think of when you pull your leg away if you step on something, your other leg has to extend to stabilize you.
267
How do intercostal nerves appear?
The intercostal nerves stay as separate segmented structures.
268
Are intercostal nerves sensory or motor function?
They contain both sensory and motor function.
Sensory for sensation of the skin overlying the ribs.
Motor for innervating the intercostal muscles for breathing.
269
What do nerves join together to form in the upper and lower body?
Plexuses
270
What are plexuses?
Network of anterior rami of spinal nerves.
271
What do plexuses allow for?
Allow for the nerves in our bodies to be formed from various levels of spinal nerves.
272
What are the two largest nerve plexuses?
Brachial plexus and lumbosacral plexus
273
Why is there a C8 spinal cord segment?
There is an extra pair of spinal nerves that reside between C7-T1.
274
What spinal cord segments does the brachial plexus range?
From C5-T1 spinal cord segments
275
What are trunks in plexuses?
These are where spinal cord nerves are joining together.
276
What are the 4 steps to forming a plexus?
1) Roots (anterior rami)
2) Trunks
3) Cords
4) Nerves (branches)
277
How many branches does each trunk give rise to?
Each trunk gives rise to 2 branches.
278
What are the names of the 3 cords?
Lateral, posterior, and medial cord.
279
What does the lateral cord branch into for nerves?
Musculocutaneous nerve and 1/2 of the median nerve.
280
What does the posterior cord branch into for nerves?
Radial and axillary nerves.
281
What does the medial cord branch into for nerves?
Ulnar nerve and 1/2 of the medial nerve.
282
If we damage the lateral cord, what nerve will be damaged?
The musculocutaneous nerve and only 1/2 of the median nerve.
283
If we damage the posterior cord, what nerves will be damaged?
The radial and axillary nerves.
284
If we damage the medial cord, what nerves will be damaged?
The ulnar nerve and 1/2 of the median nerve.
285
In what circumstance would we completely damage the median nerve?
If we damaged both the lateral and medial cord.
286
If we damaged the axillary nerve, where would we observe numbness?
The deltoid
287
If we damaged the axillary nerve, what movements would we observe the most noticeable weakness in? What muscles are responsible for this?
Shoulder abduction and external rotation.
Deltoid and teres minor
288
If we damaged the musculocutaneous nerve, where would we observe numbness?
Over the lateral forearm
289
If we damaged the musculocutaneous nerve, what movements would we observe the most noticeable weakness in?
Elbow flexion and supination.
290
If we damaged the radial nerve, where would we observe numbness?
Posterior compartment of the upper extremity and posterior digits 1 - 1/2 of 4
291
If we damaged the radial nerve, what movements would we observe the most noticeable weakness in?
Elbow extension, wrist extension, finger extension, and supination.
292
If we damaged the median nerve, where would we observe numbness?
Lateral palmar hand and digits 1 - 1/2 of 4.
293
If we damaged the median nerve, what movements would we observe the most noticeable weakness in?
Wrist flexion, finger flexion, and pronation.
294
If we damaged the ulnar nerve, where would we observe numbness?
Digits and metacarpals 1/2 of 4 - 5
295
If we damaged the ulnar nerve, what movements would we observe the most noticeable weakness in?
Finger abduction and adduction
296
If we are unsure if someone has muscle weakness on one side or if they are just weak in general, what do we do?
We need to test both sides.
297
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Axillary nerve.
Shoulder abduction and lateral rotation.
298
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Musculocutaneous nerve.
Elbow flexion and supination
299
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Radial nerve.
Elbow extension, wrist extension, finger extension, and supination.
300
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Median nerve.
Wrist flexion, finger flexion, and pronation.
301
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Ulnar nerve.
Finger abduction and adduction.
302
Label the meninges.
Top down:
Pia mater
Arachnoid mater
Dura mater
303
What kind of neuron is this?
Unipolar
304
What kind of neuron is this?
Multipolar
305
What is the lumbosacral plexus composed of?
Spinal nerves from lumbar and sacral spinal cord segments join together.
306
What gives rise to the nerves of the lower extremity?
Lumbosacral plexus
307
What is the lumbosacral plexus similar to? How is it different?
It is similar to the brachial plexus.
It is different because it comes from the back.
308
What nerves make up the lumbosacral plexus?
FOGS
Femoral, obturator, gluteals, and sciatic.
309
What are the gluteal nerves? What do these do?
Superior gluteal nerve and inferior gluteal nerve. They activate the gluteal muscles.
310
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Femoral nerve
Hip flexion and knee extension
311
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Obturator nerve
Hip adduction
312
What is the sciatic nerve made up of?
Tibial nerve and common fibular nerve.
313
Where does the sciatic nerve travel?
Down the posterior thigh.
314
What is the largest nerve in the body?
Sciatic nerve
315
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Tibial nerve
Hip extension, knee flexion, plantar flexion, and toe flexion
316
What makes up the common fibular nerve?
Superficial fibular nerve and deep fibular nerve
317
Where does the common fibular nerve travel?
Goes to the anterior and lateral compartment of the leg.
318
What innervates the short head of the biceps femoris?
Common fibular nerve
319
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Superficial fibular nerve
Eversion of the foot
320
If we observed numbness here, what nerve was damaged? What movements can we expect weakness out of?
Deep fibular nerve
Dorsiflexion, extension of toes, and inversion of foot.
321
What are the 4 types of sensory input in pathways?
Touch, Temperature, Pressure, Pain
TTPP
322
Where is motor output going to?
Muscles and glands
323
What is a primary neuron?
A unipolar neuron that brings info from the skin to the spinal cord.
324
What is a secondary neuron?
An interneuron that relays info.
325
What do tertiary neurons do?
Send info to the cerebral cortex.
326
What is in the cerebral cortex that is important for motor function?
There are upper motor neurons in the precentral gyrus that send axons down onto the spinal cord.
327
What do upper motor neurons synapse onto?
Lower motor neurons
328
What do lower motor neurons do?
They send signals to produce motor output to the muscles and glands.
329
Label the three lines
330
How do we determine spinal cord segments?
Look for the number of paraspinal nerves visible.
331
What is the role of the Posterior Funiculus - Medial Lemniscal pathway?
Relays info from the skin.
332
What initiates the Posterior Funiculus - Medial Lemniscal pathway?
Precise touch from the skin.
333
In the Posterior Funiculus - Medial Lemniscal pathway, what happens from the primary neuron to the synapse of the secondary neuron?
The primary neuron is ascending in the posterior funiculus.
334
In the Posterior Funiculus - Medial Lemniscal pathway, when does the neuron crossover to the other side of the brain?
The secondary neuron crosses over to the other side of the brain in the medulla oblongata.
335
In the Posterior Funiculus - Medial Lemniscal pathway, where is the tertiary neuron located?
In the thalamus
336
If we are trying to sense precise touch from the skin, where will the tertiary neuron send info?
To the postcentral gyrus of the cerebral cortex
337
What is the medial lemniscus?
A bundle of white matter collectively ascending. This is the secondary neuron in the Posterior Funiculus - Medial Lemniscal pathway.
338
What is this showing?
Central processes ascending in the posterior funiculus.
339
If we damaged at T6 where the arrow is shown, what would happen?
We would get the loss of precise touch sensation from the same side from T6 and down.
However, above T6, we could still sense touch.
340
What would happen if we had damage at the medial lemniscus?
This would result in the loss of sensation in the opposite side of the body.
341
What does the corticospinal pathway do?
Connects the cortex to the spinal cord to provide voluntary motor function.
342
In the corticospinal pathway, where are the upper motor neurons located?
Precentral gyrus (motor function) in the frontal lobe
343
For the upper motor neurons in the corticospinal pathway, name the percentages of divisions.
85% of the upper motor neurons are descending in the lateral funiculus.
15% of the upper motor neurons are descending in the anterior funiculus.
344
What is the anterior funiculus?
This is the projection tract, in which axons are descending down the spinal cord from the cerebral cortex.
345
Where does the crossing over of the neuron to the other side of the body occur in the corticospinal pathway?
Crossing over occurs in the medulla oblongata for the lateral funiculus.
The anterior funiculus crosses over all the way down the spinal cord.
346
If we damage C7 where the arrow is pointing in the lateral funiculus, what occurs?
There will be 85% loss of skeletal muscle strength on the same side of the body as the damage from C7 down.
347
Why does damage at C7 not result in muscle weakness in the upper extremities?
C5-T1 is the brachial plexus and this is responsible for the upper extremities.
348
If we damage L1 where the arrow is pointing in the anterior funiculus, what occurs?
Crossing over has not occurred yet so this results in 15% loss of skeletal muscle strength in the opposite side of the body from L1 down.
349
Label where the arrows are pointing
350
What is another name for the autonomic nervous system?
Visceral nervous system
351
Is the autonomic nervous system conscious or unconscious effort?
It operates without conscious effort.
352
What 3 things does the autonomic nervous system control?
Cardiac muscle, smooth muscle, and glands.
353
What are the two divisions of the autonomic nervous system?
Sympathetics and parasympathetics
354
How does the series of neurons differ between somatic and autonomic motor systems?
There is just one motor neuron in somatic motor systems. With autonomic motor systems, there are 2 neurons in series: the pre-synaptic and post-synaptic neurons.
355
What is an example of cardiac muscle?
Myocardium
356
What are 3 examples of smooth muscle?
Digestive tract, bronchi, and blood vessels.
357
What are 5 examples of glands?
Salivary, digestive, lacrimal, sweat, and sex glands.
358
What is ALWAYS the effect of the somatic motor system? How does this differ from the autonomic motor system?
The somatic motor system ALWAYS causes EXCITATION of the target.
The autonomic motor system can cause either excitation or inhibition of the target.
359
What are the 2 neurons in series called in autonomic motor systems?
The preganglionic (presynpatic) neuron and the postganglionic (postsynaptic) neuron.
360
T/F: The sympathetics and parasympathetics are running perpendicularly to the same target but have the same effects.
False! The sympathetics and parasympathetics are running in parallel to the same targets but have opposite effects.
361
How does the location of the ganglia differ between the sympathetics and parasympathetics?
In the sympathetics, the ganglia is closer to the CNS.
In the parasympathetics, the the ganglia is closer to the target.
362
What neurotransmitter is released in somatic motor neurons to skeletal muscle?
Acetylcholine (Ach)
363
What neurotransmitters are released in sympathetics to cardiac muscle, smooth muscle, and glands?
Acetylcholine is released from the presynaptic neuron. Norepinephrine is released from the postsynaptic neuron.
364
What neurotransmitter is released in parasympathetics to cardiac muscle, smooth muscle, and glands?
Acetylcholine (Ach) is released by both the presynaptic and postsynaptic neurons.
365
What is another name for the parasympathetic division? Why is this?
The craniosacral division.
The name is because the parasympathetics come from the cranial nerves and sacral spinal cord segments.
366
What is the origin of the parasympathetic/craniosacral division?
The preganglionic neurons are located in brainstem nuclei and S2-S4 regions of the spinal cord.
367
What is the function of the parasympathetic division?
This is the "rest and digest" response.
368
Name 5 things that will increase or decrease with parasympathetic activity.
1) Heart-rate decreases
2) Bronchioles constrict
3) Digestion increases
4) Salivation increases
5) Lacrimation increases
369
What is another name for the sympathetics division? Why is this?
The thoracolumbar division.
Sympathetics have presynaptic neurons located in the spinal cord at thoracic and lumbar divisions.
370
What is the origin of the sympathetics/thoracolumbar division?
Preganglionic neurons are located in the T1-L2 regions of the spinal cord.
371
What is the function of the sympathetic division?
This is our response to physical activity and our "fight or flight" response.
372
Name 6 things that can increase or decrease with sympathetics activity.
1) Heart-rate increases
2) Bronchioles dilate
3) Digestion decreases
4) Salivation decreases
5) Lacrimation decreases
6) Sweating increases
373
T/F: The parasympathetics target the sweat glands.
False! The parasympathetics do NOT target the sweat glands. We do not need to sweat when we are resting.
374
Why would the bronchioles dilate with sympathetic activity?
This allows more oxygen to get into the lungs, which is important with physical activity.
375
What is the sympathetic trunk?
A bunch of interconnected ganglia that run down the spinal cord from T1-L2.
Remember, this looks like a "string of pearls" running in the direction of the spinal cord.
376
What does the Oculomotor Nerve (CN III) do in regards to the parasympathetics?
Parasympathetics from the oculomotor nerve innervate the sphincter pupillae and ciliary muscle. This causes pupillary constriction and thickening of the lens.
377
What do parasympathetics from the oculomotor nerve innervate?
The sphincter pupillae and ciliary muscle.
378
What does innervation of the oculomotor nerve by the parasympathetics cause?
Pupillary constriction and thickening of the lens.
379
Do the parasympathetics constrict or dilate the eye?
Contrict (bright light)
380
Do the sympathetics constrict or dilate the eye?
Dilate (low light)
381
When the lens of the eye is flat, what is at work? What does this allow for?
Sympathetics make the lens flat/thin.
This is important for seeing objects in the distance.
Think of going for a run and wanting to gaze out into the distance.
382
When the lens of the eye is thickened, what is at work? What does this allow for?
Parasympathetics make the lens thickened.
This is to see closer objects.
Think of holding a PEAR close to you to eat it.
383
What 3 glands does the parasympathetic component of the facial nerve innervate?
Lacrimal gland, sublingual gland, and submandibular gland.
384
What does the parasympathetic component of the facial nerve cause?
Lacrimation, mucus production, and salivation.
385
Where does the parasympathetic component of the glossopharyngeal nerve innervate?
The parotid gland
386
What is the parasympathetic component of the glossopharyngeal nerve?
Results in salivation
387
What is the parasympathetic component of the vagus nerve?
Bronchial constriction, decrease in heart rate, and increase in digestive system activity.
388
What do spinal cord segments S2-S4 do?
They deliver parasympathetics to pelvic organs and external genitalia.
389
For somatic motor neurons, where do spinal nerves go?
Spinal nerves go to the body wall.
390
T/F: For somatic motor neurons, spinal nerves will travel to the organs.
False! Spinal nerves go to the body wall.
391
What does the body wall include?
Thoracic wall, abdominal wall, and extremities.
392
Describe the location of the sympathetic chain/trunk.
It extends up into the neck and down into the pelvis.
393
For sympathetics, what are the two directions the postsynaptic neuron can travel in?
It can go back through a connecting branch to get to the body wall or it can travel down the sympathetic trunk to the organs.
394
Why would sympathetics want to go to the body wall?
To get to the sweat glands.
395
T/F: Parasympathetics go to the body wall.
False! They do not need to, because they don't target sweat glands.
396
How do sympathetics get to organs within body cavities?
Splanchnic nerves come off of the sympathetic trunk that allow for the postsynaptic neurons to reach the organs.
397
How do sympathetics get to the body wall?
Postsynaptic neurons re-join the spinal nerves.
398
What is the fight or flight response?
This is the global sympathetic response to threatening situations, in hopes of preserving our life.
399
T/F: At any given moment, only parasympathetics OR sympathetics can be active.
False. Typically, both the parasympathetics and sympathetics are active in different branches.
400
When is the sympathetics active on every pathway?
During the fight or flight response.
401
What type of gland does the adrenal medulla contain? What does it do?
The adrenal medulla contains the suprarenal gland, which contains specialized cells that produce epinephrine and norepinephrine.
402
How do we distinguish a hormone from a neurotransmitter?
It will be identified as a hormone if it is emptied into the bloodstream.
