Neurological System Flashcards
Neurological System is divided into 2 parts
Central Nervous System (CNS)
-Brain
-Spinal Cord
Sends efferent (away) (motor) messages from CNS to effectors (muscles, organs and glands) (brain to muscles)
Peripheral Nervous System (PNS):
-Cranial Nerves (12 pairs)
-Spinal Nerves (31 pairs) + branches
Sends sensory (afferent) messages to CNS from sensory Receptors (anything to brain (touches you so you go aaaaa)
Nervous System is responsible for: 5 RSVCR
- Regulating body activities
- speech, memory, emotions and thoughts
- Various senses
- Controlling body movements
- Regulating internal organs
Three Basic Functions of Nervous System
Sensory = detect stimuli Integrative = processes info and decides what to do Motor = Activation of muscles and glands
What is a neuron
3 parts of the neuron
Functional cell of the nervous system
- Dendrites = input portion of the neuron
- Cell body = Contains nucleus and cellular organelles
- Axon = Output portion of the neuron/ Propagates action potentials (nerve impulses) to another neuron, muscle or gland cell
What is a synapse
Site of communication between 2 neurons or between a neuron and an effector cell
CNS Protection: 3 parts
Bone: 2
Skull (cranium covers and protects the brain
Vertebrae (spine) encircle and protect the spinal cord
CNS Protection: 3 parts
what is Meninges and 3 layers pad
Envelope and protect the CNS (brain and spinal cord)
Inner to outer:
- pia mater (closest to brain)
- arachnoid mater
- dura mater (closer to skull)
CNS Protection: 3 parts
What is Cerebrospinal Fluid (CSF), where is it located and its functions (4)mtrc
Clear liquid that circulates around and through the brain and spinal cord
Located in subarachnoid space
Functions: -Mechanical protection -Transport of oxygen and nutrients -Removal of wastes Circulation of chemicals
CNS: Major Components
2
Brain (4 parts) C(CB)D(TH)CB
Spinal cord
Cerebrum
- cerebral cortex
- Basal ganglia
Diencephalon
- Thalamus
- Hypothalamus
Cerebellum
Brain Stem
Cerebrum
What is Cerebral Cortex, how is it divided and its functions (5) CMRSV
Outer layer of neurons
- known as gray matter because it lacks myelin
- divided down middle, 2 hemispheres, divided into four lobes
Functions:
- Controls thought
- memory
- reasoning
- sensation
- voluntary movement
Cerebrum
Cerebral Cortex: 4 Lobes
Frontal Lobe
- Personality, behaviour, emotions, judgement, intellectual functions
- Voluntary movement
- Contains Broca’s area (motors speech)
Parietal Lobe
-Primary sensation centre
Occipital Lobe
-Primary visual receptor centre
Temporal Lobe
- Primary auditory centre
- Contains Wernicke’s area (language Comprehension)
Cerebrum
What is the Basal Ganglia and function (2)IT/AM
- Additional bands of grey matter deep within the cerebral hemispheres
- Receive input from cerebral cortex = provide output to motor neurons
Functions:
•Helps regulate initiation and termination of movements
•Control automatic associated movements like arm swing while walking & true laughter
Diencephalon
What is the function of the Thalamus(R)
Function: Main relay station for the nervous system
Diencephalon
What is the function of the Hypothalamus(CC)
Control centre for vital functions
i.e. temp, heart rate, BP, blood glucose, sleep, hormones, emotional status, regulates pituitary gland, coordinates autonomic nervous system activity
Where is the Cerebellum, how does it operate and what are its functions 5CEMCB
Under occipital lobe
Operates subconsciously
Function: -Coordination of voluntary movements -equilibrium -maintains muscle tone -Coordinates & smooths complex movements Helps maintain balance
What are the 3 areas of the brain and their functions MPM
Midbrain:
- Contains many motor neurons and tracts
- Connects diencephalon to the pons below
Pons:
- Bridge that connects parts of the brain with one another
- Contains motor and sensory tracts
Medulla:
- Connects the brain and spinal cord
- Contains vital autonomic centres (resp, cardiac, Gi function)
- Location of decussation of pyramids (90% of motor fibres cross to the opposite side)
What does the Spinal Cord contain
What is it composed of
Where does it extend from
And the functions
Contains sensory (ascending) and motor (descending) tracts
Composed of gray matter and white matter
Extends from medulla to L2
Functions:
- Primary pathway for messages traveling between the periphery of the body and the brain
- Mediates reflexes
CNS Pathways
What are the sensory receptors
What do they do
And how do they travel
How are they represented
Detect sensations in various tissues of the body
Monitor conscious sensations, organ functions, body positions, reflexes
Sensations travels in afferent (sensory) fibres of the peripheral nerve -to spinal cords - to the brain
Crossed representation - Left side of brain talks to right side (vice versa)
Sensory pathways
Spinothalamic Tract
- What is a tract
- what does it do
- what path is the impulse transmitted
Tract = Bundles of axons in the CNS
Transmits impulses for pain, temp, crude and light touch
Impulse transmitted from spinal cord - to thalamus - to cortex
CNS Pathways
Sensory Pathways
Posterior (dorsal) Columns
- What impulses does it transmit (3) pvs
- What path is the impulse transmitted
Transmits the impulses for position (proprioception), vibration, and finely localized touch (stereognosis)
- Proprioception: position, or the sense of body movements and position of body in space
- Stereognosis: the ability to identify familiar objects by touch without looking
-Impulse transmitted from the dorsal root - to spinal cord - to thalamus (then on to cortex)
CNS Pathways
Motor Fibres
- where does it originate and go
- what are the two motor neuron and where are they located
Originate in the cerebral cortex and travel down the spinal cord
Upper motor neuron - Located in CNS (corticospinal & extrapyramidal neurons)
Lower motor neuron - located mostly in the PNS [Cell body in spinal cord but rest extends into periphery]
(Cranial nerves & spinal nerve)
-Ludericks Disease, Polio, Spinal Cord lesions
CNS Pathways
Motor Pathways
-what are the two tracts and the system (What does it do, where does it originates)
Corticospinal or Pyramidal Tract
- Produces voluntary, highly skilled and purposeful movements
- originates in the cerebral cortex and travels down spinal cord
- Pyramidal decussation = majority of fibres cross over to opposite side in brain stem before travelling down spinal cord
Extrapyramidal Tracts
- Maintain muscle tone and control body movements
- Includes all motor nerve fibres originating in the CNS that are OUTSIDE the pyramidal tract
Cerebellar System
-Complex motor system that coordinates movement, maintains equilibrium and posture. Occurs on a subconscious level
Peripheral Nervous System - ‘Postman’
- Where does it deliver messages
- Where doe it carry messages
- What nervous tissue consist of
- what is it divided into and what are the functions
Delivers messages TO the CNS via sensory afferent fibers (PNS to CNS)
Carries messages FROM the CNS via motor efferent fibers (CNS to PNS)
PNS consists of all the nervous tissue OUTSIDE the CNS (Nerves are bundles of axons in the PNS)
Nerves can be divided into 2 functions: Somatic and Autonomic
- Somatic Fibers (innervate voluntary muscles: skeletal muscles)
- Autonomic fibers innervate involuntary muscles and organs: smooth muscle, cardiac muscle and glands)
PNS
What are the two major components
- where does it enter and exit
- Components?
Cranial Nerves (12 pairs)
- Cranial nerves enter and exit the BRAIN not the spinal cord
- 12 pairs (labeled I - XII)
- CN’s have either a sensor component, o motor component or both
Spinal Nerves (31 pairs) -Spinal nerves arise from the spinal cord
Spinal Nerves
- where do they connect
- why are they considered mixed
- Spinal nerves connect the CNS to sensory receptors, muscles and glands
- Are considered mixed nerves because they contain both sensory and motor fibres
Spinal nerve =What Vertebrae Level
8 cervical (c1-c8) 12 thoracic (T1-T12) 5 Lumbar (L1-L5) 5 Sacral (S1 -S5) 1 coccygeal
c1 - c7 T1 - T12 L1 - L5 S1 - S5 Coccyx
Spinal Nerve - what does is it Innervation
C1 - C3
Movement in an and above the neck (including Larynx)
c3 is also breathing
Spinal Nerve - Innervation
C4 - C6
Neck and shoulder and diaphragm and diaphragm (C3 - C5) for independent breathing
C6, C7, C8: Thumb, middle, fifth finger
Spinal Nerve - Innervation
C7 - T1
Arms and fingers and hand grasp
C6, C7, C8: Thumb, middle, fifth finger
Spinal Nerve - Innervation
T1 - T6
Provide trunk stability (sitting) and innervate intercostal breathing muscles
T1: Axilla, T4: nipple
Spinal Nerve - Innervation
T6 - T12
Intercostal and abdominal muscles - respirations/transfer strength
T10: Umbilicus
Spinal Nerve - Innervation
T12 - L4
Abdominal and upper leg muscles
L1: Groin
Spinal Nerve - Innervation
L4 - S4
Hip adductors and extensors; muscles of the knee, ankles, feet and perineum - leg strength, bladder control
L4: Knee
PNS
Dermatomes
Dermal Segmentation
Cutaneous distribution of spinal nerves
PNS
Dermatome
- What is it
- what is its mechanisms
- what is the importance of it
Area of skin supplied mainly from 1 spinal cord segment
They overlap, which is a protective mechanism if one is damaged
By knowing which spinal cord segments supply each dermatome it is possible to locate damaged regions of the spinal cord
PNS
Reflex
- what is it
- 4 parts of how it functions bqih
A fast, involuntary, unplanned sequence of actions in response to a stimulus
- Basic defense mechanism of the nervous system
- quick reaction to potentially dmging event
- involuntary and subconscious
- help maintain balance and muscle tone
PNS
Reflex Arc
- What is it
- What are the main components (5) ssime
Pathway followed by nerve impulses
Main components:
- Sensory receptor
- Sensory neuron
- integrating center
- motor neuron
- effector
For a reflex to occur all components involved must be intact1
PNS
What are the four type of reflexes
-name an example of each dsvp
Deep tendon (stretch) -patellar ( knee jerk)
Superficial (cutaneous)
-abdominal ( belly button shifts when you run something against stomach)
Visceral (autonomic)
-Pupillary ( eyes dilating)
Pathological = abnormal
-Babinski ( babys toes fan out if you draw a J on their foot, toes fan out, goes away after a certain age)
PNS
Deep tendon reflexes (DTRs) AKA stretch reflexes
- How do you get a good response
- What does testing reveal
- compared how
- Graded on?
- For a good response the muscle needs to be partially stretched with the limb relaxed
- testing of DTRs reveals intactness of the reflex arc at specific spinal levels and at higher cortical levels
- Responses compared bilaterally
- Graded on 5 point scale
PNS
Superficial Cutaneous Reflexes
- where are the receptors
- what is the response
- absent with
- sensory receptors in the skin (cutaneous layer)
- Response is a localized muscle contraction
- Absent with orders of pyramidal tract
Developmental Considerations:
Infants
-5 points and the reflexes (COME BACK AND REVIEW REFLEXES)
- Neurological system not fully developed at birth
- Major portion of brain growth occurs in the first year of life
- Neurons not yet fully myelinated
- Movements are directed primarily by PRIMARY REFLEXES (which disappear at predictable times as infants age)
- Sensory and motor development follow a cephalocaudal and proximal-to-distal order (head, neck, trunk, then extremities)
Developmental Considerations:
Older adults 8
Steady atrophy and loss of neurons in the brain and spinal cord result in:
- Changes in cognition
- Changes is motor responses
- Decreased muscle strength and impaired fine coordination
- Slowed reaction time
- Dizziness and loss of balance
- Diminished senses (pain, taste, touch, & smell)
- Diminished efficiency of the autonomic nervous system in regulating temperature and blood pressure.
