W3 L3 (Central Nervous System) Flashcards
What is the CNS?
Brain and Spinal cord
What is the PNS?
Nerve fibers that carry info to and from the CNS
What is the afferent division a part of and what does it do?
It is part of the PNS and it carries info TO THE CNS
What is the efferent division a part of and what does it do?
It is part of the PNS and it carries instructions FROM THE CNS to the effector organs
What is an effector organ?
The organ or gland that carries out the desired effect
What are the 2 divisions of the efferent division?
- Somatic
2. Autonomic
What do the somatic and autonomic nervous systems innervate respectively?
Somatic-Skeletal Muscle
Autonomic-Smooth, Cardiac, Glands
What neurons are in the somatic division?
Alpha motor neurons
What are the two divisions of the autonomic division?
- Parasympathetic
2. Sympathetic
What are afferent neurons and what division of the nervous system are they a part of?
Neurons which possess a sensory receptor at their peripheral ending and carry info to the CNS
They are part of the afferent division
What is a sensory receptor and where are they found?
It is the peripheral ending of an afferent neuron that is responsible for communicating stimuli to the CNS
Describe the structure of the afferent neuron
It is adjacent to the spinal cord and has no dendrites
What is a peripheral fiber and what is it also known as?
It is a fibre that connects the sensory receptor to the cell body, it is also known as an afferent axon
What is located between the spinal cord and the cell body?
The central axon
What are the relative sizes of the afferent axon and the central axon?
The afferent axon is much longer
What is an efferent neuron?
A neuron that carries info from the CNS to the effector organ
What is located between the Cell body and axon terminals in an efferent neuron?
The efferent fibre/axon
Where is the cell body of an afferent and efferent neuron located?
Efferent-In CNS
Afferent- In PNS
What are interneurons and what do they do?
Neurons that lie entirely within the central nervous system and are important for integrating peripheral responses to peripheral information as well as for the abstract phenomena associated with the “mind”
What type of neuron makes up 99% of all neurons?
Interneurons
What are interneurons a bridge between?
Afferent and Efferent neurons because they relay signals from one to actions of another
What is the neural axis?
The longitudinal axis of the CNS
What does the neural axis do during development?
It bends 90 degrees to accommodate our upright posture
What cross sections are typically used in brain imaging?
Coronal (frontal) or horizontal (transverse)
Where are our ancient visual and auditory centers located?
The midbrain
What is cognition?
The process of knowing which includes awareness and judgment
What are the 3 parts of the brain?
- Cerebellum
- Brainstem
- Forebrain
What are the 2 parts of the forebrain?
- Diencephalon
2. Cerebrum
What are the 2 parts of the diencephalon?
- Hypothalamus
2. Thalamus
What are the 2 parts of the cerebrum?
- Basal ganglia
2. Cerebral cortex
What are the 5 main functions of the cerebral cortex?
- Sensory perception
- Voluntary movement control
- Language
- Personality Traite
- Thoughts
What is the main function of the basal nuclei?
- Movement
What is the main function of the thalamus?
- Relay station for synaptic input
What is the main function of the hypothalamus?
- Regulation of homeostatic functions ex. temp, bladder control, food intake etc.
What is persistive vegetative state?
Being awake but not aware
What parts of the brain are damaged and which ones continue when someone is in a vegetative state?
A vegetative state occurs when the cerebrum (the part of the brain that controls thought and behavior) no longer functions, but the hypothalamus and brain stem (the parts of the brain that control vital functions, such as sleep cycles, body temperature, breathing, blood pressure, heart rate, and consciousness) continue to function.
What is the oldest region of the brain?
The brainstem
What are the 3 parts of the brainstem?
Midbrain, pons, medulla
What does the brainstem do and what systems does it control?
Controls many of life-sustaining aspects, often
referred to as “vegetative functions”. It controls the cardiovascular, respiratory, and digestive systems
What does the cerebellum do?
Maintains proper position of the
body in space and subconscious coordination
of motor activity and tone; key role in learning
skilled motor tasks
Which part of the brain is more advanced with a more advanced species?
The cerebellum
What structure is continuous with the brain stem?
The spinal cord
What structure do spinal nerves emerge from the spinal cord as?
Intervertebral foramina
What is the cauda equina?
A thick bundle of elongated nerve roots in the lower vertebral canal
What connects a spinal nerve to the spinal cord?
The ventral and dorsal roots
What is a nerve?
A bundle of peripheral neuronal axons enclosed by a
connective tissue covering and following the same pathway
What is a bundle of axons called in the CNS and PNS?
CNS-Tract
PNS-Nerve
Why is a spinal tap done at L3/L4?
It is a region containing CSF but is also below the ending of the spinal cord
What is the tectum?
The ancient visual and auditory center in the midbrain
How do nerves get elongated as we grow?
They pass through the vertebral formania and as our spinal column elongates they nerves get stretched
What happens during MS?
We lose myelin
What fibres are motor and which are sensory?
Sensory-Afferent
Motor-Efferent
What is the ventricular system?
A set of 4 interconnected cavities where CSF is produced
How many spinal nerves are there and where do they end around?
31 pairs and around T12/L1
What part of the brain is the cerebral cortex a part of?
The cerebrum
What is the corpus callosum?
The brain’s superhighway made up of 300 million neuronal axons that connect the left and right hemispheres
What is the cerebral cortex and what does it do?
The outer shell of grey matter in the cerebrum; it is the site of initiation of all voluntary motor output and final perceptual processing of all sensory input as well as integration of most higher neural activity
What are the basal ganglia and where is it located?
It is a collection of gray matter located within the white matter
What makes up the grey matter?
Tightly packed neuronal cell bodies, dendrites, and glial cells
What makes up white matter?
Myelinated axons
What is the function of stellate cells?
Initial processing of sensory input to the cortex
What is the function of pyramidal cells?
Control output of skeletal muscle
What is the function of the occipital lobes?
To carry out the initial processing of visual input
What is the function of the temporal lobes?
Initial sound sensation
What is the function of the parietal lobe?
Receiving and processing sensory information
What are the 3 main functions of the frontal lobe?
- Voluntary motor activity
- Speaking ability
- Elaboration of thought.
What does white matter of the spinal cord do?
Carry info to the brain
What are somaesthetic sensations?
Awareness of sensory input such as:
- Touch
- Pressure
- Temperature
- Pain
Where is the somatosensory cortex located?
Right behind the central sulcus at the front of each parietal lobe
What is the somatosensory cortex?
The site of initial cortical processing and perception of somaesthetic input as well as proprioceptive input
What is proprioception?
The awareness of body position
What is located in front of the central sulcus?
The primary motor cortex
What is the difference between the thalamus and somatosensory cortex?
Thalamus tells you something is different while the somatosensory cortex locates the stimuli and processes the intensity
What is the path from a sensor in the body or face to the brain
Body:
Dorsal root ganglia–>Spinal cord—>brainstem——>thalamus—>somatic sensory cortex
Face:
Trigeminal ganglia–>brainstem—>thalamus—–>somatic sensory cortex
What cranial nerves connect the brainstem to the head?
CN 3- CN 12
What mass of the brain is the cerebrum?
80%, it is also the most highly developed in humans and is the most complex integrating part of the brain
Describe the color of the cerebral cortex
The cerebral cortex is grey matter; the core is
white matter
How many layers of gray matter are there in the cerebral cortex?
6
What takes place in the gray matter of the cortex?
Integration of neural input and initiation of neural output
What does white matter in the cortex do?
Interconnects areas of the brain
What general regions are sight, auditory, motor, and somatosensory located in
Auditory-Sides
Sight-Back
Somatosensory-Back of sulcus
Motor-Front of sulcus
Where is the primary motor cortex located and what is it responsible for?
It is found behind the central sulcus and is responsible for voluntary motor output
What cells are found in abundance in the motor cortex?
Pyramidal cell neurons
What side of the body do the somatosensory and motor cortexs control?
The opposites
What parts of the brain control involuntary skeletal muscle control?
Lower parts of the brain and the spinal cord
What is the readiness potential?
The widespread pattern of neuronal discharge that occurs before the motor cortex fires
What is plasticity?
The ability of the brain to change or be functionally remodeled due to the pressures placed on it
What does motor program mean?
The three higher motor areas of the cortex and the cerebellum carry out different, related functions that are all important in programming and coordinating complex movements involving simultaneous contraction of many muscles. Signals transmitted through efferent and afferent pathways allow the central nervous system to anticipate and plan movement
What does the supplementary motor area do?
It plays a preparatory role in movements involving both sides of the body (ex.both feet)
What does the premotor cortex do?
Works in coordination with motor cortex (a few mm anterior of the primary motor cortex) to plan and execute movements
What are the primary functions of the left and right hemispheres?
Left-Thinkers
Right-Creators
What is an electroencephalogram?
A graphic record of the collective postsynaptic potential activity in the cell bodies and dendrites located in the cortical layers under a recording electrode
What are 3 functions of an electroencephalogram?
- Diagnosing cerebral dysfunction
- Pronouncing brain death
- Distinguishing various stages of sleep
What is the subcortical region?
The brain regions that lie under the cerebral cortex, including the basal ganglia, thalamus, and hypothalamus
What are the basal ganglia and what do they do?
Several masses of grey matter located deep within the white matter of the cerebrum of the brain; play an important inhibitory role in motor control
Other than movement what 3 things are the basal ganglia involved in?
- Inhibiting muscle tone
- Selecting important muscle activity and inhibiting useless
- Helping monitor slow contractions related to posture
What 2 structures make up the diencephalon?
- Hypothalamus
2. Thalamus
What is the function of the thalamus?
The brain region that serves as a synaptic integrating centre for preliminary processing of all sensory input on its way to the cerebral cortex
Where is the hypothalamus located and what does it do?
The brain region located beneath the thalamus that is concerned with regulating many aspects of the internal fluid environment, such as water and salt balance and food intake; serves as an important link between the autonomic nervous system and endocrine system
Where is the cerebellum located and what does it do?
The part of the brain attached to the rear of the brain stem and concerned with maintaining proper position of the body in space and subconscious coordination of motor activity
What are the 3 parts of the cerebellum and what do they do?
- Vestibulocerebellum- Balance and eye movements
- Spinocerebellum- Enhances muscle tone and coordinates skilled movements
- Cerebrocerebellum- Planning and initiating voluntary activity by providing input to the cortical motor areas
What are the 5 functions of the brainstem?
- Sleep
- Receives and integrates sensory synaptic input
- Regulates muscle reflexes and posture
- Control cardiovascular, digestive, respiratory
- Sensory activities
