Nervous System Flashcards
Neuromuscular system
Connection of the muscles to the brain and spinal cord
Kinesthetic sense
Kinesthesia is the awareness of the position and movement of the parts of the body using sensory organs, located in joints and muscles. Kinesthesia is a key component in muscle memory and hand-eye coordination.
Central nervous system (CNS)
Central nervous system consists of brain & spinal cord
Spinal Nerve
Large conduction tube made of thousands of nerve fibres. Starts in spinal cord in vertebrae of spine and branches out to rest of body through the PNS
Peripheral Nervous System (PNS)
Peripheral Nervous System consists of nerves that extend out from spinal cord transporting nerve impulses to/from CNS (power lines) and is divided into sensory and motor nervous systems
Sensory Nervous System
Sensory organs (eyes/ears/skin) receive info from outside peripheral world and send via sensory nerves back to CNS
Motor Nervous System
transmits info via nerve impulses away from CNS to move muscles & organs
Sympathetic Nervous System
Part of motor nervous system that prepares body for fight or flight / warm up stimulates this system
Parasympathetic nervous system
Part of motor nervous system that calms the body down (stretch exercise involving deep breathing stimulates this system)
Soma
The region of the neuron containing the nucleus is known as the cell body or soma. Located in spinal cord where axon comes out from body and connects to muscle /nerve fibres
Ganglia
Ganglia (nerve bulbs) located in spinal cord
Dendrites
Extension branches on soma, they RECEIVE impulses from other neurons within the spinal cord
Axon
Transmits signal from head to tail Trunk of neuron that conducts impulses from Soma away from spine towards muscle
Node of Ranvier
A notch on the Axon that allows impulse to jump quickly from one node of Ranvier to another on the axon
Saltatory Conduction
When impulses jump quickly from one node of Ranvier to another on the axon
Myelin sheath
Individual paddings of fat that cover the axon and allows quicker transmission of signal
Myelinated neurons
Myelin sheath is fat & protein covering axons
Nerve Fibres
Branch out from axon trunk and TRANSPORT impulses to muscle fibres
Neuromuscular Junction (NMJ)
The NMJ is the site where a motor neuron contacts muscle fibre
How does a muscle contract
- Neutral impulse sent from CNS to muscle fibre via motor neuron
- Impulse reaches NMJ and releases the neurotransmitter acetylcholine
- acetylcholine crosses synaptic cleft to muscle fibre which causes muscle to contract
Synaptic Cleft
Gap between nerve & muscle / pre and post synaptic membrane
Synaptic vesicle
Storage compartment for neutral transmitter acetylcholine
acetylcholine
Neutral transmitter that couriers the impulse from nerve to muscle
Cholinesterase
Enzyme that breaks down acetylcholine after it has transmitted the impulse
Reflex Arc (3 phases)
Reaction to danger/ pain
1. Pain stimulus (peripheral sensory perceives stimulus /pain & sends message to CNS)
2. CNS process info (processes pain as threat)
3. CNS Stella muscle to contract (pull away from threat)
Proprioceptors
Specialized sensory organs (eyes/ears) that receive & transmit info to CNS. These Proprioceptors are called muscle spindles and golgi tendon organs (GTO)
Muscle spindles
Muscle spindles are stretch receptors that signal the length and changes in length of muscles. They lie parallel to the main muscle and stretch when muscle lengthens but shorten when the muscle contracts.
-causes muscular contraction if stretch is to far (myotatic stretch reflex)
Golgi Tendon Organs (GTO)
-lives in the tendon
-senses tension
-causes relaxation
-inverse stretch reflex (hold stretch)
Sensory device imbedded in the tendon of a muscle (muscle belly) that perceives amount of tension (pull) in tendon (inverse stretch reflex)
Myotatic Stretch Reflex
Tension of Muscle stretched to limit before stretching too far
3-step muscle CONTRACTION process that causes muscle to contract when quickly stretched. The myotatic reflex is the “knee-jerk” reflex in which a muscle contracts in direct response to its stretch. It is typically elicited by tapping on the tendon
Inverse Stretch Reflex
Muscle relaxation reflex, protects muscles, tendons and joints from overloading.
2 threats to a tendon
- Too much tension (pull) due to violent contraction of muscle
- Long term tension (holding stretch too long)
GTO informs CNS and it responds by turning off muscle or when stretching, GTO is stimulated gradually to cause relaxation (autogenic inhibition)
Autogenetic inhibition
Autogenic inhibition refers to a reduction in excitability of a contracting or stretched muscle
Mobility
A joints ability to move freely through full range of motion (rom)
Flexibility
Ability of muscle to lengthen passively through range of motion.
Limiting factors to joint mobility (13)
1.Structure/shape of articulating joints
2. Strength & tautness of joint ligaments
3. Connective tissue elasticity
4. Tightness of muscles
5. Hormones (relax during pregnancy)
6. Disuse
7. Activity type
8. Aging (loss of flexibility as we age)
9. Disease (arthritis)
10. Gender
11. Temperature
12. Injury
13. Genetics
Static Stretching
-Involves slow, held, gradual and controlled stretch (active or passive)
-no joint movement
-best used AFTER exercise
-Stimulates GTO and inverse stretch reflex to relax muscle
-May prevent DOMS (delayed onset muscle soreness)
Dynamic Stretching
Joint movement that is slow or moderate while stretching
Used BEFORE exercise (warm up)
Passive Stretching
Muscle relaxed while being stretched
No contraction
(Neck muscles when you fall asleep)
Active Stretching
Muscle contracts to cause stretch
Ballistic Stretching
Dynamic stretching without control
Rapid, uncontrolled bouncing/bobbing motion/ high force and short duration
Stimulates myotatic reflex causing muscle contraction
Unsafe /two opposing force’s occur
Proprioceptive Neuromuscular Facilitation (PNF)
Form of static active stretching that involves stretching and contracting a muscle (against resistance/trainer)
Autogenic inhibition, muscle is stretched further with repetition
Autogenic inhibition
Form of static active stretching that involves stretching and contracting a muscle (against resistance/trainer)
Autogenic inhibition, muscle is stretched further with repetition
Reciprocal inhibition
Process of contracting the opposite muscle to the stretched muscle and having the stretched muscle relax further (stretch chest and contract mid back during handcuff stretch)
Elasticity & Stretching
Ability of tissue to return to normal position after being stretched
Plasticity & Stretching
Tissue remains elongated when being stretched GRADUALLY (cellophane/ plastic deformation) pairs with passive stretching
Why not bounce during stretch
Stretching is about relaxing the muscles/ bouncing causes muscle contraction. When there are two opposing forces (stretch & contraction) occurring in muscle at same time…SNAP!
Benefits of flexibility training (7)
- Improves ROM (range of motion)
- Improves performance of daily activity)
- May reduce risk of injury
- Relaxes tense muscles
- Improves posture
- Relieves stress
- Promotes circulation
ACSM
American College of Sports Medicine (ACSM)
Flexibility Conditioning & Exercise (10)
1.do not stretch to pain/ push past ROM
2. Elongation of connected tissue primary target
3. Low intensity/long duration stretches for better flexibility
4. Warmer tissue temps help range of motion
5. Flexibility is joint specific /focus on all restricted joints when stretching
6. Proper alignment needed for max effectiveness
7. Use deep breathing while stretching to activate parasympathetic system (calming body down)
8. Hold stretch 20-60 secs to release muscle (30s - ACSM guidelines)
9. Repeat stretch 4 times (ACSM guidelines)
10. Intensity of static stretch should not evoke motor unit recruitment or muscle contraction)
FITT
Frequency/Intensity/Time/Type
ACSM FITT for Flexibility
-Frequency: 2-3 times/week
-Intensity: stretch to tightness/ use light to moderate contraction (20-70%)
-Time: adults (10-30s) seniors (30-60s)
Hold/relax 5–10s of contraction at 20-75% intensity followed by 10-30s static passive stretch with 2-4reps
-Type: static passive (more time) static active (pnf) less time, dynamic (warm up) ballistic (well trained athletes)
Passive Active Stretching
Elongates muscle
What is the sensory organ involved in myotatic stretch reflex
Muscle Spindle
What is the sensory organ involved in inverse stretch reflex
Golgi Tendon Organ (GTO)
Ability of tissue to return to normal position after being stretched
Elasticity
Stretching technique that manipulates GTO to cause relaxation of muscle
Static passive
Dynamic Active Stretch
Joint moves/ muscles contract due to movement / arm swings or lunges
Dynamic passive stretches
Joint is moving because of external force (trainer assisted)
Static active stretch
Muscles contract to stretch muscle with no joint movement (raised arms/ squeezing shoulder blades)
Static passive stretch
Joint is stretched but not moving and muscles relaxed (trainee assisted or sitting cross legged)
Afferent fibres
Sensory neurons that carry information to the CNS
Sensory input
Carries info from outside world toward CNS/ brain and spinal cord
Motor output
Carries info away from CNS/brain and spinal cord OUT to organs
Motor Fibres
Sensory fibres also know as afferent fibres and carry information away from CNS
How does the Neuromuscular Junction Function
When an electrical signal reaches the axon end, Synaptic Vesicles open up and release Acetylcholine, a chemical neuron transmitter, that carries electrical signal into the Synaptic Cleft to bind on to the muscle. Once acetylcholine binds to muscle, a contraction occurs. Cholinestersae cleans acetylcholine after muscle contraction “janitor”
Synapse
Nerve fibre / the synapse secrets acetylcholine (the neurotransmitter) inside synamptical vesicle and discreet acetylcholine on to muscle fibre to contract a muscle
Proprioceptors
Kinesthetic sense is possible through sensory organs called muscle spindles and golgi tendon organs (GTO)
