Module 2 Flashcards
What are the 4 divisions of the brain?
Cerebrum
Brainstem
Diencephalon
Cerebellum
Ventricles
Cavities within the brain that are filled with cerebrospinal fluids
Contains: 2 lateral ventricles, third ventricle, and fourth ventricle
4th ventricle drains into central canal and contains CSF
Meninges
3 layers of connective tissue that cover and protect CNS organs and enclose CSF
Dura Mater
The leathery, double-layered outer menix
Subdural Space
Below the dura mater, separates dura from arachnoid
Arachnoid Menix
The middle, loose layer of meninx separated from the dura by the subdural space
Subarachnoid Space
Beneath arachnoid meninx, contains blood vessels and is filled with CSF
Pia Mater
The inner meninx, a thin connective tissue tightly attached to brain
Cerebrospinal Fluid
-A special fluid formed in the walls of the ventricles from blood plasma to cushion brain & spinal cord, provide buoyancy, and allows brain to float
-Permeates through choroid plexus
Choroid Plexus
- Formed from a network of blood vessels within the ventricles
- Produces CSF
Blood-Brain Barrier
A diffusion barrier tht prevents most particles from entering the CNS tissue, keeping the brain and spinal cord separate from general blood circulation. It is formed by the relatively impermeable brain capillaries, due to astrocytes. A stable internal environment is important to protect neurons from chemical variations which could cause uncontrollable firing of neurons.
Cerebrum
The foremost part of the brain, 83% total brain mass, 2 large masses; left & right cerebral hemisphere
Responsible for consciousness and controls actions of the cerebellum by acting on sensory input via the thalamus
Median Longitudinal Fissure
Separates the left and right cerebral hemispheres
Left Cerebral Hemisphere
Controls the right side of the body
Right Cerebral Hemisphere
Controls the left side of the body
Gyri
Raised ridges of tissue on the surface of the brain
Sulci
Shallow grooves that separate gyri
Fissures
Deeper grooves that separate large regions of the brain
Transverse Fissure
Separates cerebrum from cerebellum
Corpus Callosum
A bridge of white nerve fibers that connect the cerebral hemispheres
Cerebral Cortex
The outer portion of cerebral hemispheres, highly convoluted and gray in color
Lobes of the Brain
Frontal
Parietal
Temporal
Occipital
Frontal Lobe
Controls the higher level executive functions: reasoning & decision making, also controls motor functions and permits control over voluntary muscle actions
Parietal Lobe
Receives sensory info from receptors in the mouth for taste and located in the skin for touch, pressure, and pain
Occipital Lobe
Interprets visual input
Temporal Lobe
Has sensory areas for hearing and smelling
2 lobes on each side of brain
Primary Areas
In each lobe that receive or send info for one type of sensory or motor info for direct processing
Association Areas
Act mainly to integrate more than one type of sensory info for purposeful action
Primary Motor Cortex
a.k.a Precentral Gyrus or Somamotor Cortex
A portion of the frontal lobe, controls voluntary motor movements for all parts of the body
Primary Sensory Cortex
a.k.a Postcentral Gyrus or Somatosensory Cortex
The parietal lobe receives sensory info from the parts of the body
Association Area
Contained in each lobe, receives info from other lobes and integrates it into higher, more complex levels of consciousness
Broca’s Area
Located in frontal lobe, responsible for speech production
Wernicke’s Area
Located in temporal lobe, responsible for speech comprehension
Consciousness
Cerebrum is responsible for the state of being awake and aware of a person’s surroundings
What is Included in the Brainstem?
Medulla Oblongata
Pons
Midbrain
Medulla Oblongata
-Contains vital life sustaining centers:
>REGULATION OF HEARTBEAT
>BREATHING
>Vasoconstriction
>Vomiting
>Coughing
>Swallowing
>Hiccuping
Vasoconstriction
Constriction of blood vessels
Pons
-Functions w/ medulla for regulation of heartbeat and has reflex centers for head movements in response to visual & auditory stimuli
-Contains bundles of axons traveling btwn cerebrum and rest of CNS
Midbrain
- Relay station for tracts passing btwn cerebrum & spinal cord or cerebellum
- Also has reflex centers for visual, auditory, & tactile response
Superior & Inferior Colliculi
- Control the head & neck in response to a sudden visual or auditory stimuli
- Located on posterior portion of midbrain
What is the Diencephalon Composed of?
Hypothalamus
Thalamus
Epithalamus
Hypothalamus
- Maintains homeostasis and contains centers for regulating body functions:
>Hunger
>Sleep
>Thirst
>Body Temp
>Water Balance
>Blood Pressure - Controls the pituitary gland and serves as a link btwn the nervous syst and endocrine syst
Pituitary Gland
Regulates body hormones of endocrine system
Endocrine System
Controls the body’s hormonal production
Thalamus
Central relay station for sensory impulses traveling into the brain, receives all sensory impulses except smell
Roof of the third ventricle, last portion of brain for sensory input before cerebrum
Epithalamus
Mostly composed of the pineal gland
Forms roof of the third ventricle
Pineal Body
Secretes melatonin, regulates wake-sleep cycle
Cerebellum
-“mini-brain”
-Coordinates body movements, relays info to cerebral motor cortex:
>Maintains Balance
>Eye Movements
>Maintains Muscle Tone
-2 hemispheres w/ deep fissures subdividing into 3 lobes
-Contains outer gray matter & internal white matter
Maintaining Muscle Tone
The degree at which muscles remain partially contracted while at rest to keep bones and joints in place
Anterior & Posterior Lobes
- Receives info from body trunk
- Influences motor actions of trunk, shoulder, & pectoral girdle muscles
Vermis
Intermediate portion of cerebellum, coordinates limb movements
Cerebellar Peduncles
Connects the cerebellum to the other parts of the brain, located on anterior portion
Ataxia
Lack of voluntary muscle motor coordination
Cingulate Gyrus
(limbic lobe)
-Connects different lobes of cerebrum
-Deep to cerebrum
Hippocampus
Storage and retrieval of memories
Amygdala
A small portion of the limbic system that is involved in emotions such as rage and anger
Fornix
Bundle of nerve fibers: connection to hippocampus
Mammillary Bodies
Fibers project into thalamus that assist w/ memory of smell
“Feeling Brain”
Since stimulation of different areas of the limbic system causes rage, pain, pleasure, or sorrow.
Short Term Memory
Lasts only a few seconds
Ex: recalling a 7-digit phone #
Long Term Memory
Lasts hours to years
Ex: recalling events of the day
Basal Ganglia
- Basal Nuclei
- Responsible for coordination w/ cerebellum to regulate motor planning movements & motor learning
- Inhibitory effect on cerebral cortex
Inhibitory Effect on Cerebral Cortex (3)
- Slows & controls precise movements
- Portion in charge of motor planning
- Relays modified plan back to cerebrum
Parts of the Basal Ganglia
Caudate Nucleus
Putamen
Globus Pallidus (medial & lateral portion)
Parkinson’s Disease
A disorder of the basal ganglia
Apraxia
Difficulty w/ motor planning, results in rigid movements and executing a motor plan
Spinal Cord
Abt 17 inches long, extends from brainstem to first lumbar vertebra; terminates at the conus medullaris
Conus Medullaris
-Terminal end of spinal cord
Cauda Equina
-Extension of cord beyond L1, is a collection of nerve roots, ends at coccyx
-Spinal cord + Cauda Equina is how all electrical impulses travel btwn brain & rest of body
The Spinal Cord is Protected by…
Vertebral Column
Meninges
Cerebrospinal Fluid
Meninges
3 layers of tissue that cover and protect brain and spinal cord
Spinal Dura Mater
A single layer sheath underneath adipose tissue
(Spinal) Epidural Space
Area btwn spinal dura mater and vertebral wall contains fat and small blood vessels
(Spinal) Arachnoid Mater
-2nd innermost layer that covers the spinal cord
-CSF is btwn arachnoid and pia mater
(Spinal) Pia Mater
Innermost membrane tightly adhered to brain and spinal cord
Filum Terminate
Extension of pia mater, runs from conus medullaris to coccyx where it provides the inferior anchor for spinal cord
Spinal Cord has 2 Grooves
Anterior Median Fissure
Posterior Median Sulcus
Central Canal
An opening that runs length of spinal cord & filled w/ CSF
White Matter
Outer layer of spinal cord w/ 2 regions
Columns
Nerve fibers of white matter
Tracts
Bundles of nerve axons of white matter
Ascending Tracts
Fibers that proceed up to brain carrying sensory inputs
Descending Tracts
Fiber that proceed down the cord carrying motor outputs
Commissural
Fibers that cross over
Dorsal Root
Spinal nerve that carries incoming sensory (afferent) neurons
Dorsal Root Ganglion
Contains the cell bodies of afferent neurons
Ventral Root
Contains the axons of motor neurons
Spinal Nerve
Combination of dorsal & ventral roots on each side
Gray Matter
Inside the white matter; composed of a mixture of cell bodies of neurons
Gray Commissure
Cross over of gray matter, connects the 2 posterior & anterior horns
Anterior (Ventral) Horns
Contains somatic (voluntary) motor neurons whose axons serve as efferent pathways to skeletal muscles by way of ventral roots
Posterior (Dorsal) Horns
Serve as one of the afferent pathways from receptors by dorsal roots
Lateral Horns
Only found at thoracic level, contain autonomic (involuntary) sympathetic motor neurons whose axons serve as efferent pathways to visceral organs via ventral roots
Where is the PNS?
Outisde of CNS
Made up of nerves, apart of the somatic syst & autonomic syst
Somatic Nervous System
Contains nerves that control skeletal muscles, skin, & joints
Receptors
Exterior sense organs, receive environmental stimuli and initiate nerve impulses toward CNS
Effectors
Muscle fibers & glands that bring about a reaction to stimulus in PNS
Autonomic Nervous System
Contains nerves that control smooth muscles of internal organs and glands
Visceral Motor Nerves
Nerves in the autonomic syst. that have control over smooth muscles/involuntary functions
Cranial Nerves
- 12 paired nerves of PNS attached to the brain
- Do not intersect w/ spinal cord
- Connect muscles & organs directly to brain
Sensory Nerves
Have long dendrites of sensory neurons only
Motor Nerves
Have long axons of motor neurons only
Mixed Nerves
Have both long axons of motor neurons and long dendrites of sensory neurons
Special Sensory Nerves
Carry info for “special” senses: sight, hearing, smell, balance
Olfactory Nerve
- CN I - 1 - A
- Special sensory for sense of smell
- Only CN that is attached to cerebrum, not brainstem
- Originates in olfactory epithelium and terminates in olfactory bulbs
Optic Nerve
- CN II - 2 - B
- Special sensory nerve for sense of sight
- Originate in retinas of each eye & cross at the optic chiasm
- Synapse in the thalamus to occipital lobe to interpret info
Oculomotor Nerve
- CN III - 3 - C
- Motor nerve responsible for eye movement
- Somatic Motor : superior, inferior, & medial rectus (inferior oblique muscles for eye movement)
- Visceral Motor : dilation or contraction of pupil
Trochlear Nerve
- CN IV - 4 - D
- Somatic motor nerve responsible for movement of superior oblique (able to look down)
Trigeminal Nerve
- CN V - 5 - D/E
- Mixed (both) Nerve
- Responsible for chewing (mastication) and sensation of face, nose, & mouth
- Ophthalmic Branch, Maxillary Branch, Mandibular Branch
Ophthalmic Branch
- Sensory Nerve
- Receives sensory info from forehead, eyebrows, and upper part of nose
Maxillary Branch
- Sensory Nerve
- Receives info from lower eyelids, upper lip, upper gums, & upper teeth
Mandibular Branch
- Mixed Nerves
- Receives sensory info from lower gums, lower teeth & lips, and from the tongue; hot, cold, pressure
- Motor portion controls the muscles for mastication
Abducens Nerve
- CN VI - 6 - E/F
- Motor nerve
- Responsible for eye movement innervating the lateral rectus muscles, makes the eye move outward; abduction of eye
Facial Nerve
- CN VII - 7 - F/G
- Mixed (both) Nerve responsible for facial expressions
- Somatic Motor : muscles of facial expression
- Sensory : sensation of tongue, taste on the anterior portion of tongue
- Visceral Motor : lacrimal glands (tears), nasal mucous glands
Vestibulocochlear Nerve
- CN VIII - 8 - G/H
- Special sensory nerve responsible for hearing & balance
- Travels through a hole in temporal bone called internal acoustic meatus
- Vestibular & Cochlear branch
Vestibular Branch
Responsible for balance & equilibrium
Cochlear Branch
Responsible for sense of hearing
Glossopharyngeal Nerve
- CN IX - 9 - H/I
- Mixed Nerve
- Sensory : taste on posterior portion of tongue
- Motor : muscles for swallowing
- Visceral Motor : parotid salivary glands
Vagus Nerve
- CN X - 10 - I/J
- Mixed (both) nerve that spreads out widely in abdomen
- Responsible for digestion, heart rate, & sensation of digestive tract
(Spinal) Accessory Nerve
- CN XI - 11 - J/K
- Motor nerve responsible for rotation of head and movement of upper shoulders
Hypoglossal Nerve
- CN XII - 12 - K/L
- Motor nerve responsible for tongue movements
Nerve
Found in the PNS, consists of many axons wrapped together in connective tissue
Axons
Parts of different neurons, but when bundled together can travel to the same location in body
Ganglia
Clusters of nerve cell bodies in PNS
How Many Pairs of Spinal Nerves?
31 total
8 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Coccygeal
How Many Roots in Spinal Nerves?
2 total
Dorsal Root
Ventral Root
Rami
This is what the branches are called that spinal nerves divide into
Dorsal Ramus
- Serve the dorsal trunk
- Carries visceral motor, somatic motor, & sensory info
- Sensory info from skin & muscles of the base
Ventral Ramus
- Serve ventral trunk
- Upper/lower limbs
- Carries visceral motor, somatic motor, & sensory info to and from body surface, body wall, and limbs
Nerve Plexus
A network of interconnecting nerves from the ventral rami; cervical, brachial, lumbar, sacral
Afferent Signals
- Received by spinal nerves
- Signal passes through dorsal roots, into spinal cord, then finally up to brain for processing
Efferent Signals
- Commands are initiated in CNS, where brain decides to make a move
- Signal is sent down spinal cord to appropriate level, then out ventral roots, signal carried via spinal nerve to appropriate destination to muscle fiber to enable voluntary muscular contraction
Dermatomes
A region of skin that carries sensory info through a specific pair of spinal nerves to spinal cord and up to the brain (cervical, thoracic, lumbar, sacral)
Cervical Plexus
Ventral rami of spinal nerves C1-C4
Phrenic Nerve
- C3-C5
- Most important nerve of cervical plexus, supplies motor & sensory fibers to diaphragm
Paralysis
Loss of motor function
Ventilator
Mechanical ventilation
Brachial Plexus
Ventral rami of sensory nerves C5-T1
3 Trunks of Brachial Plexus
Superior
Middle
Inferior
2 Divisions of Trunks from Brachial Plexus
Anterior
Posterior
3 Cords from Divisions of Brachial Plexus
Lateral
Posterior
Middle
Nerves from Brachial Plexus (4)
- Long thoracic nerve
- Suprascapular Nerve
- Pectoral Nerves
- Thoracodorsal Nerves
Axillary Nerve
- Motor info to 3 muscles:
- Deltoid (muscle of shoulder)
- Teres Minor (rotator cuff)
- Long head of Triceps Brachii (elbow extensor)
- Also carries sensory info from shoulder joint
Radial Nerve
- Triceps Brachii
- 12 muscles of the forearm for wrist & finger extension
- Carries sensory info from associated joints & overlying skin
Median Nerve
- Flexor muscles of forearm
- Thenar muscles
- Sensory Info : skin on digits 1-3 and half of digit 4
Ulnar Nerve
- Flexor muscles of forearm, wrist, & hand
- Sensory Info : skin on half of digit 4 & digit 5
Musculocutaneous Nerve
- C5-C7
- Flexor muscles of elbow
- Biceps brachii
- Brachialis
- Sensory Info : skin on radial side of forearm
Lumbar Plexus
- Ventral rami of (T12)L1-L4
- 2 divisions, anterior & posterior, branch into nerves to supply the pelvis and lower extremities
Femoral Nerve
- Largest of lumbar
- Hip flexor
- Knee extensors
- Sensation : skin on anterior thigh
Lateral Femoral Cutaneous Nerve
Sensation : skin on anterior, lateral, & posterior surfaces of thigh
Saphenous Nerve
Sensation : skin from medial surface of the leg
Sacral Plexus
Ventral rami of L4-S4
Sciatic Nerve
- Largest nerve in body
- Supplies inferior trunk & posterior surface of thigh
Common Fibular (peroneal) Nerve
Travels laterally
Tibial Nerve
Travels along posterior surface of tibia
Autonomic Nervous System
A division of the PNS
Contains motor neurons that control internal organs and sensory neurons come from internal organs
Cell bodies are in the DRG for somatic sensation
Ganglia
Clusters of nerve cell bodies in PNS
Preganglionic Axon
- Motor neuron cell body located in spinal cord/brain
- This axon synapses w/ a second motor neuron located in the autonomic ganglion outside the spinal cord
Postganglionic Axon
After synapsing in an autonomic ganglion, the axon of the ganglionic motor neuron synapses on an effector organ in PNS
The Sympathetic System
- Thoracolumbar Division
- Contains preganglionic fibers from thoracic & lumbar segments of the spinal cord
- Widespread targets, cover large regions
Sympathetic System Roles
- “Fight or Flight” Response : muscles need steady, increased supply of glucose and oxygen, accelerates heart rate, dilates bronchi
- Liver breaks down glycogen to glucose
- Sympathetic activation inhibits digestion
Neurotransmitter of Symp. Syst.
-Norepinephrine (NE)
-Neuron : adrenergic
Sympathetic Trunk Ganglia
- Lateral Ganglia
- Located on both sides of spinal cord, contain ganglia for symp. syst. that controls the effector organs in the trunk, head, & limbs
Celiac Ganglia (3)
- Symp. Syst.
- Largest of ganglia
- Innervates the digestive tract
Superiomesenteric Ganglion
- Symp. Syst.
- Innervates small intestine and parts of large intestine
Inferior Mesenteric Ganglion
- Symp. Syst.
- Innervates large intestine, kidneys, bladder & sex organs
The Parasympathetic System (3)
- Craniosacral Division
- Contains preganglionic fibers from the brainstem and sacral divisions of spinal cord
- More specific targets
“Housekeeper System”
- Nickname for Parasymp. Syst.
- Responses associated w/ a relaxed state:
> Pupil constriction
> Slows heart rate
> Promotes digestion:
~ secretion of digestive glands
~ smooth muscles of GI tract
Neurotransmitter of Parasymp. Syst.
-Acetylcholine (ACh)
-neuron : cholinergic
Ciliary Ganglion (3)
- Parasymp. Syst.
- Associated w/ CN 3
- Target glands: intrinsic eye muscles, which change the pupil and lens
Pterygopalatine & Submandibular Ganglion (3)
- Parasymp. Syst.
- Associated w/ CN 7
- Target organs: tear production, nasal glands, and salivary glands
Otic Ganglion (3)
- Parasymp. Syst.
- Associated w/ CN 9
- Target glands: parotid glands
Intramural Ganglia (3)
- Parasymp. Syst.
- Associated w/ CN 10
- Target Glands: visceral organs within thoracic cavity
Traumatic Brain Injury (TBI)
- Head is moving and suddenly stopped
> head hits object
> motor vehicle accident
> sports
> falling
Brain Damage Locations
- Site of location
- Opposite side of skull due to recoil
Consussion
- Slight TBI, effects usually temporary but minor effects can linger
- Symptoms:
> dizziness
> brief loss of consciousness
> headaches - can linger
> no permanent neurological damage
Contusion
- Significant neuronal tissue damage
- Symptoms:
> unconsciousness (coma), can last hours to lifetime
Hemorrhage
A rupture in a blood vessel, causes blood to accumulate in skull
Intracranial Pressure
- The amount of pressure available inside skull
> limited due to enclosed skull
> rises after hemorrhage
Damage of Intracranial Pressure
- Damage & compression of brain tissue
- Forces brainstem down through foramen magnum
> damage to brainstem
> decreased control of heart rate
> respiration is lost
> fatal without intervention
Ataxia
- Impaired motor coordination
- Injury to cerebellum, smooth gait
Cerebrovascular Accident (CVA)
- Stroke
- Occurs when blood circulation is blocked within brain
- Brain tissue dies due to lack of oxygen & nutrients
- Severity depends on vessel blockage
Hemorrhagic CVA
- “Brain bleed”
- Blood vessels in brain ruptures
Ischemic CVA
Blockage in artery from a clot (embolus) or fat deposit
Transient Ischemic Attack (TIA)
Small clot causes a temporary blockage in flow, resolves quickly
Stroke Survivor Symptoms
- Depends on part of brain impacted
- Paralysis
- Cognitive changes
- Speech impairment
- Emotional changes
Neural Plasticity
Undamaged neurons in surrounding area spread into the area of injury
Recovery for Stroke
- Physical, occupational, speech therapy
- Act FAST:
>Facial drooping
>Arm weakness
>Speech difficulty
>Time to call 911
Alzheimer’s Disease
- Form of dementia
- Progressive degenerative disease of brain
- Results in mental decline, until brain can no longer control basic bodily functions, fatal
- Decreased brain tissue
Structural Changes of Alzheimer’s Disease
- Formation of plaques
- Entanglement of neurons
- Lack of neural firing
- Leads to neuron death
- Spreads through all brain tissue
- Shrinkage of cerebral cortex gray matter
Stages of Alzheimer’s
- Early: difficulty remembering newly learned info
- Mid: brain loss interferes w/ basic memory skills
>mood, behavioral changes (frontal lobe)
>disorientation to surroundings
>often stressful for caregivers - Late: person has difficulty speaking, swallowing, & walking
What areas of the brain does the limbic system connect?
The frontal lobes, the temporal lobes, the thalamus, and the hypothalamus
Explain why emotional memories tend to be vivid
The involvement of the limbic system explains why emotionally charged events result in our most vivid memories. The fact that the limbic system communicates with the all the sensory areas accounts for the ability of a sensory stimulus to awaken a complex memory.
Quadriplegia
Paralysis of all four limbs
Compression of the ______ nerve results in carpal tunnel syndrome
Median nerve
Compression of the ______ nerve results in the ulnar claw sign
Ulnar
Sciatica results from compression of what nerve?
Sciatic
Amyotrophic Lateral Sclerosis (ALS)
- a.k.a Lou Gehrig’s disease
- A rare neuromuscular condition that involves progressive destruction of ventral horn motor neurons
- Causes paralysis, progressively loses the ability to speak, swallow, and eventually breathe
Complete (or total) Spinal Cord Injury
- If the spinal cord is completely severed at any level
- Total motor and sensory loss is experienced in body regions below the site of the damage, even if the spinal cord is intact below the level of injury
Paraplegia
Lower limb paralysis, may occur if the spinal cord is injured between T1 and L1
Carpal Tunnel
Where the median nerve and the flexor tendons of the hand travel through
Flexor Retinaculum
A fibrous connective tissue band that forms the anterior roof of the carpal tunnel
Carpal Tunnel Syndrome
- Compression of the median nerve in the carpal tunnel, causes decreased sensation in the first three digits and half of the fourth digit
- No treatment = decreased hand strength
Claw Hand
The inability to open the 4th and 5th fingers caused by flexion at the IP joints and hyperextension of the MCP joints in digits 4 and 5
Sciatica
Increased pressure on the sciatic nerve from the surrounding muscles, resulting in pain following the path of the sciatic nerve in the lower pelvis and posterior thigh