Module 12: Neurological System (Part 02) Flashcards
This is major communication link between the brain and the PNS (spinal nerves). It participates in the integration of incoming information and produces responses through reflex mechanisms
Spinal Cord
This is where the spinal cord ends.
L2
How many pairs of spinal nerves are in the spinal cord?
It gives rise to 31 pairs of spinal nerves
(1) cervical and lumbosacral enlargement give rise to the spinal nerves of the limbs
(2) Nerves from the end of the spinal cord from the cauda equina
This separates the lumbar and the sacral region (lumbosacral).
Plexus (They are separated in different types of action mechanism, movements and innervations, specially in urination) Like the Brain
This is where action potentials work so that you can urinate.
Sacral Area
Nerves from the end of the spinal cord form the ______________.
cauda equina (tail-like part of the peripheral nerves)
Explain the structure of the spinal cord
(1) Our peripheral nerves are surround to whole of our body
(2) Dorsal root goes around the back, Ventral root goes around the front
(3) Ganglion, the head of the cell body of neurons
(4) The long one is the sympathetic chain
(5) The connections in between is called the rami that bides in the sympathetic chain
Divide the spinal cord
(1) Cervical Nerves (C1 to C8) - C1 is found in the base of your neck
(2) Thoracic Nerves (T1 - T12)
(3) Lumbar Nerves (L1 - L5)
(4) Sacral Region (S1 - S5)
(5) Coccygeal Nerves and Plexus
Where is the cervical plexus found?
C1 - C4
Where is the brachial plexus found?
C5 - T1
Where is the lumbar plexus found?
L1 - L4
Where is the sacral plexus found?
L4 - S4
Where is the coccygeal plexus?
S5 - Co
These are known as the coverings of the spinal cord.
Meninges (Latin word: membranes)
What are the three (3) meningeal layers that surround the spinal cord from superficial to deep?
(1) Dura Matter
(2) Arachnoid Matter
(3) Pia matter
This is the most superficial layer. It is located between the epidural and subdural.
Dura Matter
This is located before the subarachnoid. This is also where CSF are floating, supplies nutrients, thicker than pia mater.
Arachnoid Matter
This the innermost part or meninges. This cover the spine itself.
Pia Matter
This is the space between the periosteum of the vertebral canal and the dura matter.
Epidural Space (before the dura matter)
This is the space between the arachnoid matter and the pia matter.
Subarachnoid Space (after the arachnoid)
Explain the orientation of the epidural space and the subdural space.
The epidural space is after periosteum. Subdural is the blood vessel (left); it is where the CSF leaked or bleeding if there is trauma.
(1) Subdural hematoma trauma in the subdural region because that is where most of the blood vessels are.
(2) Epidural layer is where the anesthesia is injected like when having baby in the lumbosacral area (epidural block)
This is the bony part that is located before the epidural space.
Periosteum
Explain the orientation of the arachnoid and the subarachnoid.
(1) Arachnoid (right) is the small area that has 2 linings
(2) After is subarachnoid, this is where the CSF is.
(If there is a leak of CSF (white liquid) due to trauma, there is a problem in the subarachnoid space; harder to treat than the subdural hematoma.
These are matters located in the spinal cord cross section.
The spinal cord consists of (1) peripheral white matter and (2) central gray matter
This is organized into columns (funiculi) going up, which are subdivided into tracts (fasciculi or pathways) going down, which consist of ascending and descending axons
White matter
These are the columns in the white matter that goes up (ascending).
funiculi (there are even numbers of funiculi and the Fasciculi)
These are the tracts in the white matter that goes down (descending)
Fasciculi or pathways (there are even numbers of funiculi and the Fasciculi)
Explain the descending orientation of the brain to the spinal cord.
(1) Upper part is brain
(2) Second layer is midbrain
(3) Third layer is the pons, which is a bulb
(4) Fourth layer is the medulla oblongata
(5) Last is spinal cord.
The descending blue line is delineated as the input part, where there is receptor that will receive the stimuli.
(1) We have nerve endings in all over of our body but hands have more sensation (stored memory)
(2) Stimuli goes to primary neuron that has ganglion
(3) Then to the gray matter in the SC where there
are interneurons (connection)
(4) Subsequent to that, the stimuli does goes up funiculi (in an opposite part of the body) and stops in relay station which is the midbrain
(5) Following that, stimuli is conveyed to the gray matter of the brain
(Action potentials in the brain are needed for this transport to work; electrical impulses)
(6) Messages will return back through fasciculi; going down to gray matter of SC to the Pacini corpuscles for recognition
What are the three (3) horns in the gray matter?
(1) Dorsal Horns
(2) Ventral Horns
(3) Lateral Horns
These contain sensory axons that synapse with interneurons (upper)
Dorsal Horns
These contain the neuron cell bodies of somatic motor neurons (fat area or bulb area)
Ventral Horns
These contain the neuron cell bodies of autonomic motor neurons
Lateral Horns
What does the gray and white matter commissures do?
The gray and white commissures connect each half of the spinal cord
Where do spinal nerves arise.
Spinal nerves arise from the spinal cord in numerous rootlets. The rootlets combine to form a ventral root and a dorsal root
(There is an interneuron in the gray matter and there are tracts going up to the brain)
This root contains the sensory axons of the spinal nerve.
Dorsal Root (This is where stimuli goes into towards the spinal cord) - The somatic (skeletal muscles) and autonomic (heart rate).
This root contains the motor axons of the spinal nerve.
Ventral Root (This is where the output comes from)
These are stereotypic, unconscious, involuntary responses to stimuli. It is integral to maintain homeostasis; these are highly important for survival.
Reflex
These are reflexes mediated through the somatic motor nervous system and includes responses that
(1) Remove the body from painful stimuli
(2) Keep the body from suddenly falling
(3) Cause movement because of external forces
Somatic reflexes
These are reflexes mediated through the ANS and are responsible for maintaining variables within their normal ranges of
(1) Blood pressure
(2) Blood carbon dioxide levels
(3) Water intake
Autonomic reflexes
This is the functional unit of the nervous system
Reflex Arc
These respond to stimuli and produce action potentials in sensory neurons ( it is usually your skin).
Sensory Receptors
These propagate action potentials to the CNS.
Sensory Neurons
These are in the CNS synapse with sensory neurons and with motor neurons (more about connection carry AP to the brain)
Interneurons
These carry action potentials from the CNS to effector organs (like exocrine gland such as sweat gland; endocrine glands for metabolic rate)
Motor neurons
These are the muscles or glands, respond to the action potential
Effector organs
Explain the sequence of the reflex arc.
(1) Sensory Receptors
(2) Sensory Neurons
(3) Interneurons
(4) Motor Neurons
(5) Effector Organs
Explain the Reflex Arc (does not usually reach the brain because it happens quickyly)
(1) A stimulus is detected by a sensory receptor
(2) A sensory neuron conducts action potentials through the spinal nerve and the dorsal root to the spinal cord
(3) In the spinal cord, the sensory neuron synapses with an interneuron
(4) The interneuron synapses with a motor neuron
(5) The motor axons conducts action potentials through the ventral and spinal nerve to the effector organ.
(Usually in C1-C4 (dorsal root) it is where it passes before go to the brain when we touch something; the gray matter will pick up the sensation; exchanged it to the interneuron and it return back to the hand)
What are the three (3) types of reflexes?
(1) Stretch Reflex
(2) Golgi Tendon Reflex
(3) Withdrawal Reflex
Crossed extension reflex
What pathways interact with reflexes?
Convergent and divergent pathways interact with reflexes. Reflexes are integrated within the brain and spinal cord (Higher brain centers can suppress or exaggerate reflexes)
In this type of reflex, muscle spindles detect the stretch of skeletal muscles and cause the muscle to shorten reflexively
Stretch Reflex (Knee Jerk Reflex)
Explain the stretch reflex.
(1) Muscle spindles detect the stretch of the muscle
(2) Sensory Neurons conduct action potentials to the spinal cord
(3) Sensory neurons synapse directly with motor neurons
(4) Stimulation of the motor neurons results in action potentials being conducted to the muscle causing it contract due to being stretched (the muscle that contracts is the muscle that is affected)
How is the tendon reflex test conducted?
(1) When we do examination; we use hammer and patient is sitting down and hit the area in between patella and tibia
(2) When you touch the patella (floating bone and it is not attached). If you feel the lower part of patella, it is where your patellar tendon is
(3) The lower leg will kick forward, which is the patellar reflex or the knee jerk response
(4) When you hit the tendon, there is already stretching of the muscle called the quadriceps; the green line show where the impulse go to the gray matter. One of the impulses goes up and the other goes down to the muscle to contract. When it contracts the legs will move forward (AUTOMATIC RESPONSE)
In this reflex, the Golgi tendon (tendon in the lower part behind the knee, attached to the hamstring) organs respond to increased tension within tendons and cause skeletal muscles to relax
Golgi Tendon Reflex (will relax your leg after the stretch or contraction from the stress reflex; it is a response to the increased tension in the tendon.
This is the tendon in the lower part behind the knee, attached to the hamstring
Golgi Tendon
Explain the Golgi tendon Reflex
(1) Golgi Tendon organs detect tension applied to a tendon
(2) Sensory neurons conduct action potentials to the spinal cord
(3) Sensory neurons synapse with inhibitory interneurons that synapse with motor neurons
(4) The inhibition of the motor neurons causes muscle relaxation relieving the tension applied to that tendon
This reflex pertains to the activation of pain receptors causes contraction of muscles and the removal of some part of the body from a painful stimulus
Withdrawal Reflex (from the nociceptors of the pain, the action potentials send to the nerves, and goes back to down)
Explain the withdrawal reflex.
(1) pain receptors detect painful stimulus
(2) Sensory neurons conduct action potentials to the spinal cord
(3) Sensory neurons synapse with excitatory interneurons that synapse with motor neurons
(4) Excitation of the motor neurons results in the contraction of the flexor muscles and the withdrawal of the limb from the painful stimulus
These surround the individual axons.
endoneurium
These are known as the group of axons.
Fascicles
The group of axons known as the Fascicles are bounded together by what?
perineurium
The Fascicles form the nerve and are held together by what?
Epineurium
Spinal nerves have specific cutaneous(skin) distributions called ______________.
Dermatomes (The nerves are called dermatomes. It is the sensitive it is where the area of plexus are in the body)
Summarize the 5 areas of the spine and indicate the amount of spinal nerves.
There are 5 areas
There are 31 pairs of spinal nerves
(1) Eight cervical (C1-C8) (from the skull)
(2) Twelve thoracic (T1- T12)
(3) Five lumbar (L1-L5)
(4) Five sacral (S1-S5)
(5) One coccygeal
This makes the spine flexible.
Cartilage (When you stretch intensively (hyperextension), some of the nerves in the spine can be detrimentally affected) - lfide
This is a common neurological disorder that occurs when the median nerve, which runs from your forearm into the palm of the hand, becomes pressed or squeezed at the wrist (numbing)
Carpal Tunnel Syndrome
These are formed from the branching of the spinal nerves.
Rami
These rami supply the muscles and skin near the middle of the back
Dorsal Rami
These rami in the thoracic region form intercostal nerves, which supply the thorax and upper abdomen
Ventral Rami
These join to form plexuses
(1) Cervical,
(2) Lumbar,
(3) Sacral, and
(4) Coccygeal ventral rami
These supply sympathetic nerves
Communicating Rami
What are the five (5) major plexuses?
(1) Cervical Plexus (C1 to C4)
(2) Brachial Plexus (C5 to T1)
(3) Lumbar Plexus (L1 to L4)
(4) Sacral Plexus (L4 to S4)
(5) Coccygeal Plexus (S5 to Co)
This is the major organ of the cervical plexus located in the diaphragm, where it give spaces when you breath (contraction and relaxation)
Phrenic Nerve
What forms the brachial plexus?
(1) Axillary Nerves
(2) Radial Nerves
(3) Musculocutaneous Nerves
(4) Ulnar nerves, and
(5) Median nerves
(They work together as plexus are divided to the distribution of the upper limbs. They both supply the plexuses of the upper limbs)
These are plexuses for the lower limbs
(3) Lumbar Plexus (L1 to L4)
(4) Sacral Plexus (L4 to S4)
(5) Coccygeal Plexus (S5 to Co)
(The lumbar and sacral plexuses are often considered together as the lumbosacral plexus)
These are the nerves innervated in the coccygeal plexus.
(1) Obturator (makes your left go to the left and right), femoral,
(2) Tibial Nerves, and
(3) Common fibular nerves
(4) Femoral Nerves (in the groin)
Explain the structure of the nerves arising from the plexus.
(1) Nerves arising from plexuses are distributed to skeletal muscles throughout the body
(2) Nerves arising from plexuses also supply the skin
These are nerves that cover the GI tract.
Splanchnic Nerve (They are not considered as plexus)
The Plexus is also known as what _____________.
The braid
This is contained in the cranial activity. This is the “control center” for many of the body’s functions
Brain
What are the four (4) parts of the brain?
(1) Brainstem
(2) Cerebellum
(3) Diencephalon (consists the thalamus and the hypothalamus (it is connected to the pituitary gland)
(4) Cerebrum
What are the three (3) parts of the brainstem?
(1) Midbrain
(2) Pons
(3) Medulla oblongata
(any damage in this area, you will die. This is why the first responders put a neck brace because if not respiratory and heart rate could potentially stop)
This divides the upper part and the lower part of the brain.
Corpus Callosum