NEUROANATOMY Flashcards
Anatomical divisions
CNS and PNS
Central Nervous System (CNS
brain and spinal cord
Peripheral Nervous System (PNS)
12 cranial nerves & 31 spinal nerves
(PNS)Sensory Systems:
- Somatic (touch), Vision, Audition (hearing), Vestibular (balance), Chemical (taste & smell)
- Visceral (Autonomic: internal organs)
((PNS) Motor Systems:
- Somatic Motor System
- Innervates skeletal muscles for voluntary behaviors
- Visceral (Autonomic) Motor System
- Innervates internal organs, glands, etc. for automatic (unconscious) body functions
The CNS is protected by…
•Protected by membrane layers (meninges) and cerebrospinal fluid
Where are PNS nerves and ganglia?
THe PNS nerves and ganglia are outside of and attached to the brainstem and the spinal cord. (Cranial Nerves and Spinal Nerves)
Over Surface of CNS we have the Meninges: 3 layers of protective tissue (what are they in order of superficial to deep)?
Dura Mater, Arachnoid Mater, and Pia Mater
meninges
The meninges are the membranes covers the brain and spinal cord
Subdural hematoma
- Blood collects between the layers of tissue that surround the brain.
- Bleeding occurs between the Dura and the arachnoid.
Basic Functional Organization of the Nervous System
Functional divisions:
Autonomic and Somatic
Somatic Nervous System
Neuron Function:
- Communication: Neurons send and receive messages
- From one brain region to another
- From CNS to PNS
- From PNS to muscles, glands (motor)
- From PNS to CNS (sensory)
Neuron Components:
- Cell body or soma
- Information integration area
- Cytoplasmic extensions
- Dendrites
- “Input” zone
- Typically on soma, look like branches of a tree
- Axon
- “Output” zone
- Often a long extension, leading away from soma
Neurons (picture)
Neuron Components
- Soma: where most of the action happens
- Dendrites: conduct stimulation to soma
- Axon: carries electrical impulses to other cells
- Often surrounded by myelin sheath for insulation
nuclei
Groups of neuron cell bodies in CNS
ganglia
Groups of neuron cell bodies in PNS
tracts or columns
Bundles of axons in CNS
Nerves
Bundles of axons in PNS
Grey Matter
•accumulation of cell bodies (somas)
White Matter:
•areas made of axon tracts/columns
Anatomical Locations of the Brain
Major Subdivisions of the CNS
Spinal Cord
Medulla
Pons
Midbrain
Cerebellum
Diencephalon (thalamus & hypothalamus)
Cerebral Hemispheres (cerebrum)
left and right brain characteristics
Cerebral cortex surface is folded to increase surface area without increasing volume. What does this create?
gyrus, sulcus, and fissures
gyrus and sulcus
•Gyrus = ridge; Sulcus = groove/valley
fissure
•Fissure = very deep groove
4 main lobes to the Cerebrum
- Parietal
- Occipital
- Frontal
- Temporal
Frontal Lobe
- Located at the front of the brain
- Separated from other lobes by central sulcus
- Associated with attention, short-term memory tasks, planning, and motivation.
- Lesion to the frontal lobe an result in inappropriate responses to a situation.
Broca’s Area
- Region in the frontal lobe associated with language processing
- Research by Pierre Paul Broca indicated impairments to this area resulted in:
- Lost ability to speak (Broca’s aphasia or expressive aphasia)
- Ungrammatical speech
Parietal Lobe
- Integrates sensory information, especially for skin:
- Touch
- Temperature
- Pain receptors
- Sends information to the thalamus
- Some language processing areas.
- Damage to this area will result in Hemi-spatial neglect.
Primary Motor Cortex
- The region of cortex that is used to plan and execute movements.
- Sends long axons down to the spinal cord, which connect to the muscles.
- Motor information
SENSORY CORTEX
Portion of the human brain responsible for the processing and integration of tactile information
Homunculus
- Representation of the anatomical divisions of the primary motor cortex and Primary somatosensory cortex.
- How body parts are rendered according to how much of the somatosensory cortex is devoted to them
- Distorted appearance because it depends on the amount of cerebral tissue devoted to the given body region.
Temporal Lobe
Processing sensory input to derive meaning for the appropriate retention of:
- Visual memories
- Language
- comprehension
Lesion can result in:
- Aphasia
- Dyslexia
- Impaired verbal memory
- Impaired musical skills
- Deafness
- And more….
Wernicke’s Area
- Lesion in the superior temporal gyrus
- Damage results in receptive, fluent aphasia
- The person with aphasia will be able to fluently connect words, but will lack meaning.
Occipital Lobe
Visual processing center
- Damage to this area can result in:
- Vision loss
- Visual hallucinations
- Color agnosia
- Movement agnosia
summary of lobes
Frontal lobe—conscious thought; damage can result in mood changes, social differences, etc. The frontal lobes are the most uniquely human of all the brain structures.
Parietal lobe—plays important roles in integrating sensory information from various senses, and in the manipulation of objects; portions of the parietal lobe are involved with visuospatial processing
Occipital lobe—sense of sight; lesions can produce hallucinations
Temporal lobe—senses of smell and sound, as well as processing of complex stimuli like faces and scenes.
Cerebellum
- Attached to the bottom of the brain.
- Plays an important role in motor control.
- Does not initiate movement, but contributes to coordination
Lession in cerebellum (cerebellar ataxia)
Lesion can resulted in cerebellar ataxia:
- Loss of equilibrium
- Altered walking gait
- Problems with skilled voluntary and planned movements
Ventricles
- Hollow spaces deep within brain filled with (and circulating) cerebro-spinal fluid (CSF)
- 2 lateral ventricles (one in each hemisphere)
- 3rd ventricle (midline, between two hemispheres)
- Connects to lateral ventricles
- 4th venticle (dorsal to pons of brainstem)
- Connects to 3rd ventricle
Basal Ganglia (basal nuclei)
caudate nucleus, putamen, globus palidus
Organization/guidance of motor functions
Thalamus
relay station ànearly all sensory systems have a nucleus here
Where do the large axon tracts carry information?
- between hemispheres (corpus callosum, anterior commissure)
- to/from cerebral cortex
internal capsule
major pathway linking cortex to rest of brain and spinal cord)
The thalamus is involved in several functions of the body including:
- Motor Control
- Receives Auditory, Somatosensory and Visual Sensory Signals
- Relays sensory signals to the cerebral cortex
- Controls sleep and awake States
Corpus callosum
- Connects left and right hemispheres
- Facilitates communication between left side of the brain and right side
Agenesis
•Failure of the Corpus Callosum to develop during embryonic growth
Sometimes associated with:
- Maternal nutritional deficiencies
- Infections
- Fetal alcohol syndrome
- Craniofacial abnormalities
Hydrocephalus
- Buildup of too much cerebrospinal fluid in the brain.
- Can be congenital, or present at birth.
- Causes include genetic problems and problems with how the fetus develops.
- Normally, this fluid cushions your brain.
- When you have too much, though, it puts harmful pressure on your brain.
- An unusually large head is the main sign of congenital hydrocephalus.
What is the conductive link between the body and brain that connects to medulla(middle)of brainstem
The spinal cord
Sensations such as touch, pressure, vibration, motion, pain that ________ in limbs, neck, and trunk _______ through SC to brain
arise in the limbs and ascend through the spinal cord to the brain
Head & neck sensations pass through ___________via ______________
brainstem via cranial nerves
Commands for voluntary movements in limbs, neck, trunk originate in the________ and _______ through ________ to target muscles
originate in the brain and descend through the spinal cord
SC tissue lies in the vertebral canal: What are the vertebraes?
- 8 cervical vertebrae
- 12 thoracic v
- 5 lumbar v
- 5 sacral v
- SC tissue extends from the __________to________
- Beyond is the _________(“horse’s tail”): spinal nerve roots
base of skull to the 1st or 2nd lumbar vertebrae
horse’s tail =cauda equina
31 spinal segments
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
One nerve between each pair of adjacent vertebrae, these become ….
spinal nerves
Spinal Nerves carry…
motor, sensory, and autonomic signals between spinal cord and rest of body
Each spinal nerve is formed from…
dorsal and ventral roots
Dorsal roots are…
afferent (sensory) axons
Relay sensory info to CNS
Ventral roots are
efferent (motor) axons
Relay motor info from CNS to rest of body
3 segments of brainstem
- Midbrain
- Pons
- Medulla
•Connected to spinal cord via the ________.
medulla
The cranial nerves originate in…
the brainstem.
Trigeminal Nerve (5th cranial nerve)
- Mixed nerves
- Motor to muscles of mastication
- Sensory information from the facial muscles
Trigeminal Branches
Vestibulocochlear (8th cranial nerve)
- sensory
- Also called acoustic or auditory nerve
- Auditory information and sense of movement in space
- Hearing and balance
Acoustic Neuroma
- Uncommon, benign and usually slow-growing tumor that develops on the main nerve leading from the inner ear to your brain
- Can cause hearing loss, ringing in your ear and unsteadiness.
Glossopharyngeal
- Mixed
- Motor to the tongue
- Taste posterior 1/3
- Sensory from the soft palate
- Sensory to posterior 1/3 of tongue
What is the most important cranial nerve in Speech Pathology?
The Vagus
The Vagus
- Mixed nerve
- Called the wanderer, most extensive
- Branches recurrent laryngeal, pharyngeal, superior laryngeal
- Intrinsic muscles of the larynx
- Taste posterior tongue
- Pharyngeal and palatal muscles
- Cricothyroid
Accessory Nerve
- Motor
- Intrinsic muscles of the larynx, pharynx and soft palate
- Sternocleidomastoid and trapezius
- Lesions
- Unable to turn head
Hypoglossal nerve
- Motor
- Motor function of the tongue
What supplies the head and neck with oxygenated blood?
Carotid Artery
Major arteries’ of the Neck
Vertebral Artery
What supplies blood to the brain and surrounding structures?
Circle of Willis(common place of aneurisms)
What supplies blood to the anterior temporal lobes and is one of the three major paired arteries that supply blood to the cerebrum?
Middle Cerebral Artery (MCA)
Occlusion to the MCA can result in:
- Paralysis
- Sensory loss of the contralateral face and arm
•Wernicke’s or Broca’s Aphasia
•Contralateral neglect syndrome.
blod clot
- Thrombus, or blood clot
- Healthy response to injury intended to prevent bleeding
- But can be harmful when clots obstruct blood flow through healthy blood vessels.
Aneurysm
- Blood filled, balloon like bulge in the wall of a blood vessel.
- If an aneurysm increases in size, the risk of rupture increases.
Infarction
Tissue death caused by local lack of oxygen, due to an obstruction of the tissue’s blood supply.
