Anatomy/Physiology Flashcards
What are glial cells?
Surround neurons and provide support for and insulation between them, which increases the speed at which impulses travel through the neural system.
Support neuronal function by regulating the environment of the nervous system and providing protection against harmful agents.
White matter; on the inside of the brain and the outside of the spinal cord.
What are myelin sheaths? What are their role in speech?
Formed by glial cells. They surround the axons of neurons, providing electrical insulation and thereby increasing the speech of AP.
Damage of myelin sheaths = MS
What neurons can regenerate if injured? Those in the PNS or CNS?
PNS.
CNS neurons have little regenerative capabilities due to their tendency to retract their processes and/or die after injury
Describe the two subdivisions of the PNS
Somatic nervous system
- Supports sensation and motor function. Movements that are consciously perceived and volitionally controlled
Autonomic nervous system
- Supports functions that are mostly below conscious awareness
How many pairs of cranial nerves are there?
Name the nerves, sensory or motor and what the control.
12
- Olfactory - Sensory
- Smell
- Optic - Sensory
- Processes visual info
- Damage can cause vision loss / difficulties reading/writing
- Occulomotor - Motor
- Trochlear - Motor
- Trigeminal - Sensory +
Motor- S: Facial sensation M: Jaw movements
- Crucial for oral sensations during speech and feeding
- Damage = facial numbness or jaw dysfunction
- Abducens - Motor
- Facial - Sensory + Motor
- Controls facial expressions and taste for anterior 2/3 of the tongue
- Bell’s Palsy affects this nerve, leading to facial droop
- Vestibulocochlear - Sensory
- Hearing and balance
- Glossopharyngeal - Sensory + Motor
- Taste for posterior 1/3 of tongue and aids in swallowing
- Influences swallowing and gag reflexes
- Vagus - Sensory + Motor
- Affects lungs, heart and digestive process
- Crucial for voice production
- Damage = vocal fold paralysis and dysphagia
- Accessory - Motor
- Controls specific neck muscles
- Damage = muscle weakness, difficulty with posture and keeping head up - Hypoglossus - Motor
- Controls tongue movements
- Damage = tongue weakness/paralysis
How many pairs of spinal nerves are there?
31
- Afferent nerves are sensory or motor?
- Efferent nerves are sensory or motor?
1.Sensory
2. Motor
the CNS is covered by 3 layers of protective membranes called the meninges. These layers are…. (describe them)
- Pia
- The thin fibrous sheet that tightly
adheres to the surface of the
brain and spinal cord
- The thin fibrous sheet that tightly
- Arachnoid
- Spider weblike mesh of fibers
providing a region through
which cerebral spinal fluid can
flow
- Spider weblike mesh of fibers
- Dura
- the tough durable sac made of
dense fibrous tissue that
surround the entire brain and
spinal cord
- the tough durable sac made of
(PAD)
Describe Hydrocephalus.
When the flow of cerebral spinal fluid through the ventricular system is blocked, it causes elevated CSF pressure.
How many ventricles in the brain?
4
- Right ventricle
- Left ventricle
- Third ventricle on the midline of the brain
- Fourth ventricle at the base of the cerebellum
3 major segments of the brainstem and describe what they do
- Medulla oblongata
- The lowest segment of the brainstem that contains neural circuitry for respiration, cardiac rate, and reflexes such as coughing, vomiting, and swallowing
- Pons
- The region of the brainstem where several cranial nerves have their associated nuclei (including motor nuclei for chewing, facial expressions, vestibular, and cochlear sensory functions)
- Midbrain
- The region of the brainstem that processes visual and acoustic information
- Periaqueductal gray in the midbrain is important for what speech functions?
- Lesions can cause what?
- The PAG plays a vital role in coordinating phonatory, articulatory, and respiratory movements for sound production
- Mutism
What role does the cerebellum play? Lesions create:
Plays an important role in motor control by comparing motor intent and motor outcome. it sends error correction info to the motor cortex.
Lesions = disrupts the coordination and precision of motor behaviours
(ataxia)
Describe Reticular formation
a collection of cell collins and interconnecting networks (centered in the pons) that coordinate motor functions of the head (such as mastication and articulation)
The anterior portion of the frontal lobe (the prefrontal cortex) contributes to…
- executive functioning
- attention
- monitoring
- planning
- decision making
Pyramidal system:
1. What does it contain?
2. What are the 2 divisions?
- Upper motor neurons: Found in cerebral cortex/brainstem. Transmits nerve impulses from brain to lower motor neurons.
- Lower motor neurons: Found in brainstem/spinal cord. Transmits nerve impulses from upper motor neurons to muscles
- Corticospinal: The UMN originate in the primary motor cortex, descend through the internal capsule, once they reach the transition point from the brainstem to the spinal cord, the fibers crossover in the pyramidal decussation and control muscles on the opposite (contralateral) side of the body
CS: Synapses/terminate in spinal cord. Controls movements in limbs and trunk
(hint: corticospinal - spinal cord)
- Corticospinal: The UMN originate in the primary motor cortex, descend through the internal capsule, once they reach the transition point from the brainstem to the spinal cord, the fibers crossover in the pyramidal decussation and control muscles on the opposite (contralateral) side of the body
CB: Synapses/terminate in brainstem. Controls muscles of face, head, neck
(hint: corticobulbar - brainstem)
- Corticobulbar: controls the muscles of the face and neck. Contains UMN in the cerebellum and LMN in the brainstem. It is typically bilateral control, with the exception of CN VII (lower face) and CN XII (tongue), where it is controlateral
Efferent vs afferant nerves
Efferent: motor nerve, sends signal down to the nerve to innervate muscle (efferent exits)
Afferant: sensory nerve, signal come up from sensory organ via nerve to brain (afferent arrives)
What is the function of the direct motor pathway?
To control skilled, voluntary movements to our extremities
- What is the final common pathway?
- Damage to the final common pathway results in…
- Where the axons that project from lower motor neurons contact striated muscle
- muscle paresis or paralysis, muscle atrophy, fibrillations
True/False: the basal ganglia exerts direct motor control
False; the basal ganglia contribute inhibitory or facilitatory input to the cortex
interruption to the directions and indirect pathways in the basal ganglia lead to…
movement disorders of initiation or muscle tone
- tremors
- athetosis
- ballism
- chorea
What is athetosis (symptom)? What disorders have this as a symptom?
slow, repetitive writhing movements
Describe chorea. What disorders have chorea as a symptom?
rhythmic, repetitive jerking movements
Huntington’s disease
Describe ballism. What disorders have this as a symptom?
sudden, jerky flinging movements
Pryramidial vs extrapyramidial systems
Pyramidial: Tracts (originate in cerebral cortex) carry fibers to –> spinal cord/brainstem. Voluntary control (body + face muscles)
Extrapyramidal: Tracts (originate in brainstem) carry fibers to –> spinal cord. Involuntary & Automatic control (tone, balance, posture, etc.)
Define these positional terms:
1. Unilateral
2. Bilateral
3. Ipsilateral
4. Contralateral
5. Proximal
6. Distal
7. Anterior
8. Posterior
9. Rostral
10. Caudal
- One side innervating
- Both sides innervating
- Same side of body
- Opposite side of body
- Near given position
- Away from given position
- In front of
- Behind
- Front, towards the nose
- Back, towards the tail
How many signals is sourced from the primary motor cortex?
Half or more of all of the body motor control signals
Broca’s area (Location and role)
- Inferior frontal gyrus in the left hemisphere
- Important for language production
Location of the primary somatosensory cortex
The most anterior portion of the parietal lobe, the post central gyrus
What is the premotor cortex is involved in? What lobe is it located in?
the performance of skilled motor movements such as those necessary for speech, grasping, etc. Frontal lobe.
What is the importance of the homunculus in relation to the primary motor cortex?
The homunculus demonstrates that functions requiring relatively more neural processing take up relatively more cortex
What information does the somatosensory cortex receive?
- body sensations (excluding hearing and vision)
- it is also organized with sensitive regions taking up relatively more cortex
where is the primary auditory cortex located?
wishing the superior surface of the temporal lobe superior to Heschl’s gyrus
Wernicke’s area (location and role)
- adjacent to the primary auditory cortex in the left hemisphere
- Important for language comprehension (spoken and written)
What are the 3 major divisions of the brain? Describe their roles.
- Forebrain
- Two subdivisions: Telencephalon and Diencephalon
- Largest brain division: Processes sensory info, reasoning/problem solving, automatic, motor functions- Midbrain
- Regulates movements and processes visual and auditory info
- Houses substantial nigra (production of neurotransmitter - dopamine)
- Connects the forebrain to the hindbrain
- Hindbrain
- Regulates autonomic functions, balance, equilibrum, relay of sensory info
- 2 subdivisions: Metencephalon and Myencephalon
- Midbrain
What are the two subdivisions of the forebrain? Describe their roles.
Telecephalon
- Cerebral cortex (divided into four different major lobes: frontal, parietal, temporal, occipital)
Diencephalon
- Connects endocrine with nervous system: Thalamus, Hypothalamus, Pineal Gland
What are the 2 subdivisions of the hind brain? Describe their role.
Metencephalon: Pons & cerebellum
Myencephalon: Medula oblongata
3 types of white matter in the CNS :
- Association fibers: Fibers within the cerebral hemisphere that form short connections between adjacent gyri or longer connection between lobes
- Commissural fibers: Transverse fibers that connect the two hemispheres of the brain
- Projection fibers: connects cerebral cortex to the brainstem and below
- White matter that is interhemispheric:
- White matter that is intrahemispheric:
- Commissural fibers (connects right and left hemispheres)
- Association fibers (within the same hemisphere)
Describe the function of the circle of willis and its 3 major arteries.
Connects the internal carotid and vertebral/basilar system
Artieries:
- Middle cerebral artery
- Anterior cerebral artery
- Posterior cerebral artery
What are the 6 cranial nerves important for speech? Why?
CN V: Trigeminal
CN VII: Facial
CN IX: Glossopharyngeal
CN X: Vagus
CN XI: Accessory
CN XII: Hypoglossal
Group of 4 muscles responsible for chewing? Why?
Muscles of mastication.
Masseter muscle:
- Muscle of mastication that connects mandible and cheekbone. Elevates mandible and closes the mouth .
Temporalis muscle:
- Muscle of mastication that retracts and elevates mandible, side to side movement. Large, fan-shaped muscle
Medial pterygoid:
-Muscle of mastication that connects mandible with maxilla, sphenoid, & palatine bones. Elevates mandible and protrudes the jaw.
- Lateral pterygoid:
Muscle of mastication that depresses and protrudes mandible to open mouth. Two-headed muscle located in infra temporal fossa of skull
Thick, dome-shaped muscle that separates the abdomen from the thorax
Diaphragm
In adults, the breathing cycle occurs ____ per minute
12-18x