Neuroanatomy Lecture Powerpoint Flashcards
The cranial nerves with exception to CN__ are part of the ____, not the ___
CN II, PNS, CNS
Neuron
Non-reproducing unit of nervous system composed of a body, dendrites (receivers), and axon (conductor) surrounded by a myelin sheath, has greatest sensitivity of any cells to oxygen and glucose deprivation and thus shows first signs of hypoxia or hypoglycemia
Grey matter vs white matter
Grey matter is neural cell bodies located on the inner part of the spinal cord and outer part of the brain vs white matter is axons (myelin sheaths) located at the outer spinal cord or inner portion of the brain
Sensory/afferent neurons
Communicate stimuli toward the CNS such as light, heat, or pressure
Motor/efferent neurons
Conduct signals way from CNS mostly leading to muscle cells and other target organs
Interneurons
Lie entirely within the CNS and have an integrative function to associate, process, store, and retrieve information and interconnect incoming sensory to outgoing motor pathways
3 reasons bony anatomy is important to cranium
- Injury to bony anatomy can affect deeper underlying structures
- CT scans, need to be able to identify suture lines vs fractures
- Skull is a “closed box” particularly susceptible to any swelling
List the suture lines of the skull (5)
Corneal - formed between parietal and frontal bone
Sagittal - Formed between the two parietal bones at the dome of the skull moving anterior to posterior
Lambdoid - formed between occipital and parietal bones
Bregma - point of intersection between corneal and sagittal sutures
Lambda - Point of intersection between sagittal suture and lambdoid sutures
Meninges (definition and the 3 of them)
3 layers of tissue covering the CNS including…
The dura mater (thick outer layer of vascular connective tissue that forms dural sinuses between 2 layers periosteal and meningeal, also forming falx cerebri and tentorium cerebelli)
The arachnoid mater (nonvascular thin filamentous connective tissue that adjoins but does NOT adhere to dura allowing for subdural potential space, meanwhile subarachnoid space beneath it is where CSF and veins/arteries flow)
The pia mater (thinnest delicate layer that adheres directly to surface of brain and spinal cord invaginating along the surface)
Epidural hematoma definition and appearance on CT
Arterial bleed between skull and osteum dura often in skull fractures appearing as “football shaped” bright lesion on side of head on CT scan
Subdural hematoma definition and appearance on CT
Tearing of the bridging veins between the meningeal dura and arachnoid mater appearing as a crescent shaped lesion on CT scan of head
Subarachnoid bleed definition and appearnce on CT
Bleed in the subarachnoid space above the pia mater that tends to layer within sulci and gyri of brain due to tearing of subarachnoid vessels that appears as layering around the invaginations of the brain on a CT scan
Rostral vs caudal and dorsal/ventral
Rostral is towards the front/anterior of the brain that then shifts superiorally moving down the brain to the spinal cord, vs caudal is toward the back/posterior of the brain that then shifts inferiorally moving down the brain to the spinal cord, with dorsal and ventral being perpendicular to these points
3 main parts of the brain
1) forebrain (composed of telencephalon and diencephalon)
2) midbrain (mesencephalon)
3) hindbrain (metencephlaon and myelencephaon)
Mid brain and hind brain combine to form the….
…brainstem
Parts of telencephalon (4)
- Cerebrum and all of its cortexes
- Basal ganglia
- Amygdala
- Hippocampus (all part of limbic system)
Cerebrum
Largest portion of brain divided into 2 halves called hemispheres, communicating with each other thru corpus callosum, functions for thought, voluntary movement, language, reasoning, and perception, cerebrum is a gross division of brain that has many subdivisions and sub regions
Cerebral cortex definition and the lobes of the cerebral cortex (4)
Outer layer of grey matter in the cerebrum that is highly convoluted into ridges (gyri) and grooves (sulci/fissures)
The lobes of the cerebral cortex include
Frontal - goal oriented, motor, cognitive functions
Occipital - visual perception
Parietal - touch, pain, limb position, size/shape perception
Temporal - perceive, localize sound, visual form/color, emotions
Fissure vs sulci
Fissures are deep groves consistently present from one brain to next vs sulci are not as deep and can vary in location
Longitudinal and transverse cerebral fissure
Separate left and right hemisphere and cerebrum from cerebellum, invaginated by the falx cerebri and tentorium cerebelli overlying
Central sulcus and lateral sulcus
- Divides frontal from parietal lobe creating a precentral gyri and post central gyri on each side
- Divides parietal lobe from temporal lobe
Pre-central gyrus
Located directly anterior to the central sulcus containing the motor cortex
Post-central gyrus
Located directly posterior to the central sulcus containing the somatosensory cortex
Frontal lobe
Largest lobe responsible for planning, complex movements, organizing, problem solving, and higher cognitive function, has a prefrontal cortex for higher cognitive functions and premotor and primary motor cortex (premotor modifies movement and stores muscle memory from primary motor), as well as olfactory bulb is on inferior aspect
Frontal lobe injury can cause… (4)
- Lack of focus/organization
- Difficulty learning new info
- Loss of inhibition
- Inability to retrieve recent memories
Broca’s aphasia
Injury to frontal lobe at the broca area (most commonly found in left hemisphere at posterior portion of inferior frontal gyrus) causes partial loss in ability to produce language (spoken, manual, or written), patients are aware that they cannot speak properly but can comprehend perfectly well (often known as motor or expressive aphasia)
Parietal lobe
Integrates sensory information from perceptions of touch, pain, limb position (includes postcentral gyrus/somatosensory cortex), controls how we receive info about the environment around us such as distance and position of object
Parietal lobe injury can cause… (4)
- Inability to discriminate between stimuli
- Locate and recognize parts of body
- Process/integrate diverse sensory info for speech and perception
- Write accurately
Temporal lobe
Controls audiory processing/ability to recognize words, auditory cortex allows for perception and localization of sound (receives sounds from ears and areas process info into meaningful speech or words) also perception of visual form and color, participates in processing of new memory also plays a role in mediating emotions
Temporal lobe injury causes… (4)
- Left side difficulty remembering what people said
- Right side may impair recalling music or pictures
- Difficulty perceiving or localizing sound
- Difficulty perceiving visual form and color
Wernicke’s aphasia
Injury to area located on the temporal lobe near the caudal end of the lateral sulcus that causes fluent but meaningless speech with comprehension generally being impaired, speech may sound fluent but pattern is disordered and illogical (global aphasia)
Occipital lobe
Visual center, area allows to interpret what looking at including visual perception, differentiating form and color, and facial recognition
Occipital lobe injury causes… (4)
- Visual impairment
- Visual hallucinations
- Impaired color perception
- Inability to recognize faces
Parts of limbic system and their function, what portion of the forebrain are they part of?
- Amygdala (emotional responses, hormonal secretion, emotional memory)
- Hippocampus (learning and memory)
- Cingulate gyrus (emotion, pain, memory)
Not absolutely part of telencephalon or diencephalon
Parts of diencephalon (3)
- Limbic system (sorta this sorta telencephalon)
- Thalamus (relays info between cortex and brain stem, role in alert/awakeness
- hypothalamus (body temp, emotion, hunger, thirst, circadian rhythm, pituitary gland control)
Parts of mesencephalon/midbrain (2)
1) Tectum - more posterior component considered roof of midbrain, has the superior colliculus involved in visual reflexes and inferior colliculus involved in auditory reflexes, the 4 colliculi form the corpora quadrigema)
2) Tegmentum - floor of midbrain, network of neurons involved in many reflexive pathways, has motor centor that sends inhibitory signals to the hypothalamus
Cerebellum
Part of metencephalon located on posterior-inferior portion of brain that functions in coordination of voluntary movement, balance, posture, motor learning and reflex memory
Pons
Part of metencephalon that relays sensory info between forebrain and hindbrain, houses cranial nerve nuclei V-VIII, contains pneumotaxic centers that help regulate respiration