Anatomical Orientation and the Nervous System Flashcards
define anatomical plane
reference planes used to describe sections of the body: sagittal, coronal and transverse
define sagittal plane
divides the body into left and right parts
define coronal plane
divides the body into anterior (front) and posterior (back) parts
define transverse plane
divide the body into superior (upper) and inferior (lower) parts
define anterior
refers to the front side of the body
define posterior
refers to the back side of the body
define superior
refers to a position closer to the head or upper part of the body
define inferior
refers to a position closer to the feet or lower part of the body
define medial
refers to a position closer to the midline of the body
define lateral
refers to a position farther from the midline of the body
define ventral
refers to the front side or belly side of the body
define dorsal
refers to the back side of the body
define proximal
refers to a position closer to the point of attachment
define distal
refers to a position farther from the point of attachment
define superficial
refers to structures located closer to the outer surface of the brain
define deep
refers to structures located farther from the surface and toward the core of the brain
define internal
refers to structures situated within or inside the brain
define external
refers to structures located on or near the outer aspects of the brain
define palmer surface
anterior surface of the hand (the palm)
define dorsal surface
posterior surface of the hand (back of the hand)
define plantar surface
refers to the bottom or sole of the foot
define surface
refers to the top side of the foot
define cranial
refers to a position closer to the head or skull
define caudal
refers to a position closer to the tail or lower end of the body
define rostral
refers to a position closer to the front of the brain or toward the nose
define occipital
refers to a position near or related to the back of the brain, specifically the occipital lobe
define unilateral
refers to a structure or condition occurring on only one side of the body
define bilateral
refers to structures or conditions present on both sides of the body
define ipsilateral
refers to structures or conditions occurring on the same side of the body
define contralateral
refers to structures or conditions occurring on the opposite side of the body
define midline
refers to unpaired structures
define glial cell
a non-neuronal cell in the CNS that supports, nourishes, and protects neurons
define astrocyte
a type of glial cell that provides structural support, regulates blood-brain barrier functions, and maintains the extracellular environment in the CNS
define neuron
a nerve cell responsible for transmitting electrical signals throughout the nervous system
define capillary
a small blood vessel in the CNS that facilitates the exchange of gases, nutrients, and waste products between the blood and brain tissue
define microglia
the immune cells of the CNS that acts as macrophages, clearing debris and responding to injury or infection
define oligodendrocyte
a type of glial cell in the CNS that produces myelin, which insulates axons to increase the speed of nerve signal transmission
define cerebrum
the largest part of the brain, responsible for higher cognitive functions, sensory processing, voluntary motor control, and complex behaviours
define diencephalon
located deep in the brain, it includes structures that relay sensory information and regulate autonomic functions
what does the diencephalon include?
- hypothalamus
- thalamus
- pineal gland
define hypothalamus
regulates vital functions such as temperature, hunger, thirst, and the release of hormones from the pituitary gland
define thalamus
acts as the main relay station for sensory information, directing signals to appropriate areas of the cerebral cortex
define pineal gland
produce melatonin, which helps regulate sleep-wake cycles
define brainstem
connects the brain to the spinal cord and controls basic-life sustaining functions like heart rate, breathing, and swallowing
what does the brainstem include?
- midbrain
- pons
- medulla oblongata
define midbrain
involved in visual and auditory processing, as well as motor control and coordination
define pons
serves as a bridge for communication between the cerebrum and cerebellum and helps regulate breathing
define medulla oblongata
controls autonomic functions such as heart rate, blood pressure, and respiration
define cerebellum
coordinates voluntary movement, balance, and motor learning, ensuring smooth and precise movements
define central canal
a small, fluid-filled passageway that runs the length of the spinal cord, containing cerebrospinal fluid (CSF) and connecting to the ventricles of the brain
define gyri/gyrus
raised ridges or folds on the surface of the brain that increase its surface area, allowing for more neurons and enhanced cognitive function
define sulci/sulcus
shallow grooves or indentations on the brain’s surface that separate adjacent gyri and help define the boundaries of different brain regions
define fissures
deep grooves in the brain that divide major brain regions, such as the longitudinal fissure, which separates the two cerebral hemispheres
define central sulcus
a groove separating the frontal and parietal lobes, and the motor from the sensory cortext
define precentral gyrus
a ridge located in the frontal lobe of the brain housing the primary motor cortex responsible for voluntary motor control of skeletal muscles
define postcentral gyrus
a brain ridge containing the primary somatosensory cortex, responsible for processing sensory information from the body
define longitudinal fissure
the deep groove that divides the brain into the left and right cerebral hemispheres
define diencephalon
a brain region between the brainstem and cerebrum, containing the thalamus, hypothalamus, and pineal gland, involved in sensory processing and homeostasis
define midbrain
the part of the brainstem that controls vision, hearing, motor coordination, and regulates arousal and alertness
define vermis
the central part of the cerebellum that connects the two hemispheres and helps coordinate body posture and movement
define primary fissure
a deep groove in the cerebellum that separates its anterior and posterior lobes
define posterior lobe
the largest lobe of the cerebellum, involved in coordination of voluntary movements and fine motor control
define folia
thin, leaf-like folds on the surface of the cerebellum that increase its surface area for neural processing
define meninges
the three protective membranes (dura mater, arachnoid mater, pia mater) that surround and protect the brain and spinal cord
define dura fold
extensions of the dura mater that form partitions within the cranial cavity, stabilising and supporting the brain by separating its regions
what is the falx cerebri?
separates the two cerebral hemispheres along the midline
what is the falx cerebelli?
separates the two hemispheres of the cerebellum
what is the tentorium cerebelli?
separates the cerebrum from the cerebellum
define superior sagittal sinus
a large venous channel located along the upper edge of the flax cerebri, responsible for draining blood from the brain into the venous system
define straight sinus
a venous channel draining deep brain veins into the confluence of sinuses
define confluence
a meeting point where multiple venous sinuses in the brain converge
define incisura tentorii
an opening in the tentorium cerebelli that allows the brainstem to pass between the cerebrum and cerebellum
define diaphragma sellae
a small, circular fold of dura mater that covers the sella turcica and surrounds the pituitary gland, leaving an opening for the pituitary stalk
define sella turcica
a saddle-shaped depression in the sphenoid bone of the skull that houses the pituitary gland
what are the three common types of CNS herniations
- transtentorial (uncal) herniation
- tonsillar herniation
- subfalcine herniation
define transverse sinus
a venous sinus located along the posterior part of the tentorium cerebelli, draining blood from the brain to the sigmoid sinuses
define herniation
abnormal displacement of brain tissue from one area to another, often due to increased intracranial pressure, compressing vital structure and impairing function
define subfalcine herniation
displacement of the brain tissue under the flax cerebri, potentially compressing the anterior cerebral artery
define transtentorial (uncal) herniation
displacement of brain tissue through the tentorial notch, compressing the brainstem
define tonsillar herniation
downward movement of cerebellar tonsils through the foramen magnum, compressing the medulla
symptoms of subfalcine herniation
common, headache contralateral leg weakness
symptoms of transtentorial (uncal) herniation
occulomotor (CN III) paresis - weakness/paralysis of occulomotor nerve, affecting eye movement
(ipsiliateral dilated pupil, abnormal EOM’s), contralateral hemiparesion
symptoms of tonsillar herniation
obtundation - reduced level of consciousness with decreased alertness and responsiveness
All three meningies: dura mater, arachnoid mater and pia mater are filled with what fluid?
The subdural space is filled with subdural hematoma
The subarachnoid space is filled with cerebro-spinal fluid (CSF)
define periosteum
a connective tissue membrane covering bones, providing nourishment and attachment points for muscles
what are the two types of dura mater
- periosteal layer
- meningeal layer
what does the periosteal layer do?
outer layer of dura mater, provides protection and structural support
what does the meningeal layer do?
inner layer of dura mater, forms partitions (dural folds) within the brain to support and stabilise the brain, and creates venous sinuses for blood drainage
define arachnoid villus
small protrusions of the arachnoid mater into the venus sinuses that allow cerebrospinal fluid (CSF) to be absorbed into the bloodstream
order of layer of the brain
- skin of scalp
- periosteum
- bone of skull
- dura mater
- periosteal
- meningeal
- arachnoid mater
- pia mater
- arachnoid villus
- blood vessel
- falx cerebri
where does the CSF come from?
produced via the choroid plexus in the ventricles of the brain
what are the three ventricles involved with the CSF?
- lateral ventricle
- third ventricle
- fourth ventricle
what is the role of the lateral ventricle?
located in each hemisphere of the brain, they produce and circulate cerebrospinal fluid (CSF) through the brain’s ventricular system
what is the role of the third ventricle?
located between the two halves of the diencephalon, it connects to the lateral ventricles via the interventricular foramen and helps circulate CSF
what is the role of the fourth ventricle?
positioned between the brainstem and cerebellum, it drains CSF into the subarachnoid space around the brain and spinal cord
what is the relationship between the ventricles (where CSF is produced) and the subarachnoid space?
- specialised tissue called the choroid plexus produces the CSF
- fluid flows from the ventricles into the subarachnoid space to protect and nourish the brain and spinal cord
what happens if the CSF doesn’t return to the circulation?
it can cause hydrocephalus, leading to increased intracranial pressure, brain swelling and potential neurological damage
what is hydrocephalus usually caused by?
usually involves dysfunction in the arachnoid villi or venous sinuses - where CSF is typically reabsorbed into the bloodstream
what is used to treat hydrocephalus?
catheter draining CSF from the ventricles into the peritoneal cavity
role of the frontal lobe
responsible for executive functions such as decision-making, problem-solving, motor control, and personality
role of parietal lobe
processes sensory information like touch, temperature, and spatial awareness
role of occipital lobe
primarily responsible for visual processing and interpretation
role of temporal lobe
involved in auditory processing, memory, and language comprehension
what is the insula?
a region of the cerebral cortex located deep within the lateral sulcus, involved in processing emotions, perceptions, and autonomic functions
how are the cortices in the cerebral cortex usually organised?
Most primary cortices are located around the deepest sulci/ fissures such as:
- the central sulcus: surrounded by primary somatomotor & somatosensory cortices
- the lateral fissure : surrounded by primary auditory and gustatory cortices
- the calcarine sulcus: surrounded by primary visual cortex
role of primary somatosensory cortex
Located in the postcentral gyrus, processes sensory information from the body
role of primary (somato-) motor cortex
Located in the precentral gyrus, it controls voluntary muscle movements.
role of primary gustatory cortex
Located in the insula, it processes taste.
role of auditory cortex
Located in the temporal lobe, it processes auditory information
role of visual cortex
Located in the occipital lobe, it processes visual information
role of parieto-occipital fissure
separates the parietal and occipital lobes, marking the boundary between sensory processing and visual areas
role of lateral fissure
Separates the temporal lobe from the frontal and parietal lobes, important for organizing brain regions involved in auditory processing and language.
role of calcarine sulcus
Located in the occipital lobe, it contains the primary visual cortex, responsible for processing visual information
what is the broca’s area?
region in the frontal lobe responsible for speech production and language processing
role of the prefrontal cortex
responsible for executive functions, such as decision-making, problem-solving, emotional regulation, and social behavior
what is the frontal eye field?
A region in the frontal lobe that controls voluntary eye movements and visual attention
what is the premotor cortex?
A region of the frontal lobe that plans and coordinates voluntary movements before they are executed by the primary motor cortex
what are the areas associated with vision?
- visual association area
- primary visual cortex
what is the visual association area?
Interprets visual information from the primary visual cortex
what is the primary visual cortex?
Processes raw visual information, such as light, color, and shapes
what are the areas associated with hearing?
- wernicke’s area
- auditory association area
- primary auditory cortex
what is the Wernicke’s area
A brain region in the temporal lobe essential for language comprehension
what is the auditory association area?
Interprets sounds and associates them with meaning
what is the primary auditory cortex?
Processes basic auditory information like pitch and volume
what does the central sulcus separate?
The central sulcus separates the frontal lobe from the parietal lobe.
Where is the primary somatomotor cortex located, and what is its function?
The primary somatomotor cortex is located in the frontal lobe and is the center for somatomotor output.
what is the role of the pituitary gland?
Regulates various endocrine functions by secreting hormones that control growth, metabolism, reproduction, and stress response.
role of the spinal cord
transmits neural signals between the brain and the body, and coordinates reflexes and motor control
role of the cerebellum
Coordinates voluntary movements, balance, posture, and motor learning
role of superior colliculus
Involved in visual processing and controlling eye movements, particularly in response to visual stimuli
what is the fornix?
A fiber tract connecting the hippocampus to other brain regions, involved in memory
what is the corpus callosum?
A fiber bundle that connects the brain’s left and right hemispheres
define cingulate gyrus
A brain region involved in emotion, behavior, and cognitive functions
where is the brainstem located?
between the diencephalon (interbrain) and the spinal cord
define grey matter cortex
The brain’s outer layer, containing neuron cell bodies, responsible for processing and integration
define grey matter nuclei
Clusters of neuron cell bodies within the brain, involved in processing information
define white matter in brain
Brain tissue made up of myelinated axons, responsible for transmitting signals between different brain regions
What role do oligodendrocytes and Schwann cells play in the nervous system?
Oligodendrocytes in the CNS and Schwann cells in the PNS provide insulation to nerve axons by forming the myelin sheath.
Why do fiber tracts in the brain and spinal cord appear white?
The myelin sheath formed by oligodendrocytes gives axonal bundles a white appearance, leading to the term “white matter.”
Cervical cord (C1-C8)
Controls the neck, arms, diaphragm, and upper chest, with nerves responsible for movement and sensation in these areas.
Thoracic cord (T1-T12)
Controls the chest and abdominal muscles, as well as some back muscles, contributing to respiration and trunk stability.
Lumbar cord (L1-L5)
Controls the lower back, hips, and legs, influencing movement and sensation in the lower extremities.
Sacral cord (S1-S5)
Controls the pelvis, bowel, bladder, and sexual function, as well as sensation and movement in the lower limbs.
what is the cauda equina?
A bundle of nerve roots at the end of the spinal cord that innervates the lower body.
what are cervical and lumbar enlargements?
- Cervical enlargement: An expanded region of the spinal cord (C4-T1) that supplies nerves to the upper limbs.
- Lumbar enlargement: An expanded region of the spinal cord (T11-L2) that supplies nerves to the lower limbs.
what is the dural tube?
A protective membrane surrounding the spinal cord and brain.
What are the two main functions of white matter tracts in the spinal cord?
To transmit sensory information to the brain (ascending tracts) and motor commands from the brain (descending tracts).
Name the examples of sensory (ascending) tracts.
- Dorsal column-medial lemniscus system
- spinocerebellar tract
- anterolateral system
What is the role of the dorsal column-medial lemniscus system?
It carries fine touch, vibration, and proprioceptive sensory information to the brain.
Name two examples of motor (descending) pyramidal tracts.
Lateral corticospinal tract and anterior corticospinal tract.
What is the primary function of the lateral corticospinal tract?
To control voluntary motor movements, particularly of the limbs.
what is included in the Dorsal column-medial lemniscus system?
- gracile fasciculus
- cuneate fasciculus
what is included in the spinocerebellar tracts?
- anterior and posterior spinocerebellar tract
what is included in the anterolateral system?
lateral and anterior spinothalamic tract
what is included in the extrapyramidal tract?
- rubrospinal tract
- reticulospinal tract
- olivospinal tract
- vestibulospinal tract
what is the difference between the pyramidal and extrapyramidal tracts?
Pyramidal tracts: Responsible for voluntary motor control, particularly precise and skilled movements, by directly connecting the brain’s motor cortex to the spinal cord
Extrapyramidal tracts: Responsible for involuntary and automatic motor control through indirect pathways involving various brainstem nuclei.
