Module 5 Flashcards
The nervous system is the body’s…
control and communication system
What are the three functions of the nervous system?
1) Sensory Input
2) Integration
3) Motor Output
Describe sensory input. What are the two places sensory input is gathered from? What is sensory input detected by?
Allows us to gather sensory information about external environment (ex. touch, temperature, sound) and internal environment (ex. distension of the urinary bladder).
Sensory input from the environment is detected by sensory nerves and travels through the body to communicate with other nerve cells.
Describe integration. What occurs during this stage? Integration incorporates multiple signals. Where does integration occur?
Nervous system needs to put together all the incoming sensory signals to create a complete picture of the environment.
For example, the brain is able to integrate different sound signals from each ear to determine the location of a sound’s source.
Integration occurs in the brain or spinal cord.
Describe motor output. What occurs during this stage? What carries out the function? Where do they send signals from and where to?
Nervous system functions to produce an appropriate response by sending motor output signals through motor nerves.
These nerves signals from the brain and spinal cord to the skeletal, cardiac, or smooth muscle of the body, causing them to contract or relax.
What are the two principal subdivisions of the nervous system?
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
What is the central nervous system made of?
Brain and spinal cord
The CNS is commonly referred to as the ________________ of the body.
Control center
What is the PNS composed of?
All the nerves outside the brain and spinal cord
What are types of nerves in the PNS (there are 4).
- Cranial Nerves
- Spinal Nerves
- Autonomic/Somatic Nervous System
- Special Sense Organs
What are the two divisions of the PNS
Motor (Efferent)
Sensory (Afferent)
What are the two divisions of the Motor (Efferent) in PNS
Autonomic
Somatic
What are the two divisions of the Autonomic in Motor (Efferent).
Parasympathetic
Sympathetic
What is the sensory division responsible for?
- Sending information (sight, smell, touch, pain) to CNS through sensory nerves
- Travels up spinal cord to brain for processing
What is the motor division responsible for?
- signal sent from CNS to target
- can be voluntary/involuntary
What does the somatic nervous system control?
- Voluntary movement
What does the autonomic nervous system control?
- Involuntary Movement
What are the two parts of the autonomic system?
- Sympathetic Division (fight or flight)
- Parasympathetic (rest and digest)
When you’re eating or resting, which autonomic system is most active?
- Parasympathetic
When you’re working out or scared, which autonomic system is most active?
- Sympathetic
Do the parasympathetic and sympathetic systems produce opposite responses?
Yes
What are nerve cells called?
Neurons
Nerve cells are ___________ and transmit _________ electrical signals to other neurons
excitable, rapid
What are the parts of a neuron?
- Cell body
- Cytoplasmic processes (dendrites & axon)
What are the cytoplasmic processes of a neuron?
- Dendrites & axon
What receives neuronal signal from other neurons and transfers those signals to the cell body?
Dendrites
What is the cell body also called?
The soma
What houses the nucleus and other organelles?
Cell body
What functions to transfer electrical signals from the dendrites to the axon?
Cell body
How many axons are there per neuron?
One
What carries the signal from the cell body to the axon terminals, where the signal is then transferred to other neurons or organs?
Axon
What do nerves communicate through (rapid transduction of electrical signals)?
Nerve impulse
How many directions do nerve impulses travel?
One direction - unidirectional
Neurons can be classified based on the number of cellular ___________ (dendrites and axons) that extend from the cell body
processes
______________ neurons have one cellular process that SPLITS into a dendrite and axon
Pseudounipolar
What are an example of pseudounipolar neurons?
General sensory nerves
____________ neurons have one dendrite and one axon that extend directly from the cell body. They have two distinct cellular processes.
Bipolar
Which type of neuron has two distinct cellular processes?
Bipolar neurons
Where are bipolar neurons found?
Special senses like sight and hearing
_____________ neurons have multiple dendrites, one axon, summing to three or more cellular processes. The number of dendrites is variable
Multipolar
What are the most common type of neurons?
Multipolar
What are an example of multipolar neurons?
Motor neurons
Which type of neuron has three or more cellular processes?
Multipolar
What are the supporting cells of the nervous system called?
Neuroglia or glia
Neuroglia generate or transmit nerve impulses. TRUE or FALSE
FALSE; They aid in sending signals between neurons to improve communication, but don’t generate or transmit signals themselves
Glia means _______, so neuroglia holds it all together
glue
What are the four supporting cells of the CNS?
Astroglia
Microglia
Ependymal
Oligodendrocytes
What are the large start shaped cells called?
Astroglia
What do astroglia do?
Communicate with neurons and blood vessels to maintain integrity of the tissue
What are the most abundant glial cells in the CNS?
Astroglia
What do microglia do? (2)
Protective functions
- Phagocytose (engulf and destroy pathogens)
- Eliminate waste products from other cells
What are the least common type of supporting cells?
Microglia
What shape are ependymal cells? Where are they located?
- Cuboidal
- Line cavities of brain and spinal cord
What do ependymal cells do? (3)
- Assist in production, circulation, and monitoring of cerebrospinal fluid
What do oligodendrocytes do?
Wrap around axons in CNS to form myelin sheath
How many axons can a single oligodendrocyte myelinate?
*they have multiple processes that extend to myelinate axons
60
What is myelin composed of? What colour is it? What does it do? Does it result in slower or faster speed which electrical signals can travel down axon?
Mainly fat
White
Insulates axon
Increases speed at which electrical signals can travel down axon
What are unmyelinated nodes between adjacent regions of myelination known as? What’s another name for them?
Nodes of Ranvier
Neurofibril nodes
What’s the main type of neuroglial cell in the PNS?
Schwann cell
What do Schwann cells do?
Form myelin sheath around nerve fibers (axons) in PNS
A single Scwann cell can myelinate…
a portion of an axon
What is the brain housed and protected by?
The skull
What are the parts of the cerebrum?
Telencephalon
Diencephalon
What are the three parts of the brainstem?
Midbrain
Pons
Medulla
Where is the cerebellum located?
- Back of brainstem
- Underneath occipital lobe of cerebrum
What’s the function of the cerebellum?
Coordinates motor activity
What makes up the bulk of the cerebrum?
Telencephalon
What is the telencephalon responsible for? (3)
Interpreting sensory signals
Sending out motor signals
Decision making
The cerebrum is made up of two paired ________________ (right and left)
Cerebral hemispheres
What separates the cerebral hemispheres?
Longitudinal fissure
What is the outer layer of the cerebrum known as? What colour is it in coronal section?
Cerebral cortex
Dark grey
What are the smaller fissures or grooves on the cerebrum known as?
Sulci
What does the folding of the cerebrum help with?
Increases surface area of neural tissue, increasing the functional capacity of the tissue
What are the lumps and bumps in the cerebrum known as?
Gyri
What does the lateral sulcus divide?
Temporal lobe from frontal and parietal lobes
What does the precentral sulcus do?
Creates anterior border of motor cortex
What does the central sulcus divide (in terms of lobes and cortex)?
Frontal and parietal lobes
Motor from sensory cortex
What does the postcentral sulcus do?
Creates posterior border of sensory cortex
What does the parieto-occipital sulcus divide?
Parietal and occipital lobes
Where is the parieto-occipital sulcus most prominent? (Which view)
Medial surface on hemisphere/midsaggital section
Which view/cut is the lateral sulcus absent?
Midsaggital section
Which gyri is located anteriorly to central sulcus? What is its function?
Precentral Gyrus (Motor Cortex)
- Sending motor output signals
- Located anteriorly to central sulcus
Which gyri is located posteriorly to the central sulcus? What is its function?
Postcentral Gyrus (Somatosensory Cortex)
- Receiving sensory input related to touch and feel
- Located posteriorly to central sulcus
What is Lissencephaly? What is it caused by?
Smooth brain syndrome
Lack of development of sulci and gyri of brain
What are symptoms of smooth brain syndrome?
Limited mental capacity
Severe intellectual disability
Slowed physical development
Incompatible with life beyond 10 years
What are the four lobes of the cerebrum? Hint: they are named after their overlying bones
Frontal
Temporal
Parietal
Occipital
What does grey matter consist of (3)? Where is it located in the brain (2)?
Nerve cell bodies
Short interneurons
Glial cells
Found in:
Cerebral cortex
Inner areas of brain
What does white matter consist of? Where is it located?
Bundles of nerve fibres and axons
Inner regions of cerebrum
What region of white matter connects the two hemispheres of the brain?
Corpus callosum
What is a treatment for severe seizures (to prevent spreading of seizures from one side of brain to other)?
Cutting off corpus callosum
Doesn’t stop seizures but reduces severity
The second layer, the diencephalon is ________ to the telencephalon.
Deep
What is the central core of the cerebrum?
Diencephalon
What is the diencephalon responsible for? (2)
Sensory and motor relay into and out of the brain
Control of autonomic system
What are the two components of the diencephalon?
Thalamus
Hypothalamus
What does the diencephalon enclose?
Third ventricle (fluid filled cavity)
What is the thalamus? How many bodies does it have?
Deep brain structure with two bodies; one in each hemisphere
What is the thalamus responsible for relaying?
Sensory information to other areas of brain EXCEPT smell
Where is the hypothalamus located?
Small structure below thalamus
What is the hypothalamus connected to?
The pituitary gland
What does the hypothalamus control?
Release of hormones through pituitary gland
What is the function of the brainstem?
Connects brain to spinal cord
Where is the brainstem located?
Just below diencephalon
What is the brainstem comprised of (three parts)
Midbrain
Pons
Medulla oblongata
Why is the midbrain important?
Contains many autonomic reflex centers and white matter tracts necessary for human functioning and survival
What is the most superior aspect of the brainstem?
Midbrain
Anteriorly, what does the midbrain consist of? Large _______ tracts that make up…
Large white matter tracts that make up cerebral peduncles
What are the pair of raised bumps from an postero-lateral view called?
Inferior and superior colliculi
What is the structure in the middle of the brainstem called?
Pons
Where is the pons located relative to the 4th ventricle and cerebellum.
Anterior to 4th ventricle and cerebellum
What does the pons have fibres connecting it to to allow for communication?
To the cerebellum
What is the most inferior structure of the brainstem?
Medulla oblongata
Which part of the brainstem is continuous with the spinal cord?
Medulla oblongata
What relays sensory information and controls the release of hormones?
Diencephalon
What area of the brain is responsible for motor coordination?
Cerebellum
What is organized into four lobes, each with different functions?
Telencephalon
What area of the brain attaches to the spinal cord?
Brainstem
What are two protective measures for the brain?
Meninges and ventricles
What are meninges?
Connective tissue membranes protecting the structure of the CNS
What is the most superficial and tough of the meninges?
Dura mater
What is dura mater composed of in CNS? What does it attach to?
A double layer of connective tissue that attaches firmly to the skull.
What does the dura mater invaginate into (3)?
1) Longitudinal fissue creating falx cerebri between cerebral hemispheres
2) Transverse fissure between cerebrum and cerebellum, known as tentorium cerebelli
3) Space at midline of cerebellum, known as falx cerebelli
What does arachnoid matter do?
Loosely covers brain
What space does the arachnoid mater create? What is it filled with?
Subarachnoid space
Filled with cerebrospinal fluid (protective) AND blood vessels
What layer of of the meninges is the pia mater? What does pia mater firmly attach to?
Innermost layer
Cerebral cortex
What are ventricles? How many are there? What do they contain?
Made of 4 hollow spaces that are continuous with each other and spinal cord
Contain cerebrospinal fluid
What are the paired C shaped spaces deep within cerebral hemisphere called?
Lateral ventricles
True or false: A portion of the lateral ventricles can be found in each lobe
True
Where is the third ventricle located?
In the middle of the diencephalon between the two halves of the thalamus
What connects the lateral ventricles to the third ventricle?
Interventricular foramina (of Monro)
Where does the fourth ventricle sit between?
Pons/medulla and cerebellum
What connects the fourth ventricle to the cerebellum?
Cerebral aqueduct
What is the fourth ventricle continuous with (2)?
Central canal of spinal cord and subarachnoid space
What is cerebrospinal fluid produced inside? By what?
Ventricles - primarily by choroid plexus (collection of ependymal cells and blood vessels)
What are the three main functions of CSF?
1) Buoyancy effect to brain, and spinal cord (weightless when surrounded by CSF)
2) Support and protection (shock absorber)
3) Medium for transport of nutrients, waste, dissolved gases, other substances
What is the journey of CSF (starting from lateral ventricles)?
1) CSF produced in paired ventricles, flows through interventricular foramina (foramina of Monro) to third ventricle
2) From third ventricle, flows through cerebral aqueduct to fourth ventricle
3) From fourth ventricle, leaves ventricular system to enter subarachnoid space and central canal of spinal cord
The spinal cord facilitates communication between the central nervous system and the peripheral nervous system through _____________ nerves
Spinal
Spinal nerves exit the spinal cord to supply sensory and motor innervations to regions close to the level of ________
exit (ex. spinal nerves exiting from upper cervical region will serve head and neck, spinal nerves from thoracic will serve thorax)
Spinal cord begins at the ____________ ___________ of occipital bone
foramen magnum
Spinal cord extends inferiorly to the level of L2, known as the __________ _____________
conus medullaris
Inferior to L2, the axons emerging from the spinal cord are known as ________ __________
cauda equina
Within the cauda equina, a small thin strand of _____ _________, known as the ________ ____________, anchors the spinal cord to the sacrum and coccyx
pia mater, filum terminale
What is the region of spinal cord that is continuous with the brainstem and housed in bones of the neck?
Cervical
What is the region of the spinal cord that is located within the vertebrae of the upper back?
Thoracic
What is the third region of the spinal cord?
Lumbar
What region contains conus medullaris, and from which cauda equina arises?
Sacral
Where is the spinal cord enlarged? Why?
Cervical, lumbar
Additional nerves exiting spinal cord that supply limbs
Cervical enlargement supplies innervation to the _______ limb, while the lumbar enlargement serve the _________ limb
upper; lower
How many layers of dura mater in spinal cord?
One
What is between the external surface of dura mater and bone in spinal cord?
Fat-filled epidural space
TRUE or FALSE: The subarachnoid space in the spinal cord is continuous with the subarachnoid space of the brain?
TRUE
Deep to the arachnoid mater is the ________ mater, which in the spinal cord, directly attaches to it
Pia
The spinal cord contains inner _______ matter and outer _________ matter.
grey, white
What colour matter are ventral, dorsal, and lateral horn?
Grey
What information does the ventral horn carry?
Motor
What type of information does the dorsal horn carry?
Sensory
What horn is between the anterior and posterior horns?information does it carry?
Lateral/intermediate
Carries information from sympathetic nervous system
White matter lines the outside of grey matter in the spinal cord. It contains tracts of fibers separated into the anterior, lateral and posterior ___________ (bundles)
funiculi
What facilitates communication within one hemisphere?
Association fibres
What facilitates communication between the two hemispheres, where two structures join
Commissural fibres
What facilitates communication between different levels of the CNS (ex. brain and spinal cord)
Projection fibres
