Reflex Physiology Flashcards
Reflexes are rapid, predictable, involuntary motor responses to stimuli that function over pathways called ______.
reflex arcs
Reflexes can be categorized into two large groups:
1.
2.
-Somatic reflexes
-Autonomic (or visceral) reflexes
______ include all those reflexes that involve stimulation of skeletal muscles by the nervous system
Somatic reflex
(Ex: rapid withdrawal of a hand from a hot object)
_______ are mediated through the autonomic nervous system. These reflexes activate smooth muscles, cardiac muscles, and the glands of the body, and they regulate body functions such as digestion, elimination, blood pressure, salivation, and sweating.
Autonomic (or visceral) reflexes
Reflexes that are mediated through spinal nerves without involving the higher brain centers are…
spinal reflexes
Reflexes mediated by cranial nerves are termed…
cranial reflexes
All reflex arcs have 5 essential components…
1.
2.
3.
4.
5.
- Receptor
- Sensory Neuron
- Integration Center
- Motor Neuron
- Effector
______ is the site of stimulus action
receptor
The ____ transmits afferent impulses to the CNS.
sensory neuron
The ______ consists of one or more neurons in the CNS
integration center
The ______ conducts efferent impulses from the integration center to an effector organ.
Motor neuron
The ______, muscle fibers or glands, responds to the efferent impulses.
Effector
What is the clinical significance of reflex testing?
It is an important diagnostic tool for assessing the condition of the nervous system. Unusual or absent reflexes may indicate degeneration or pathology of portions of the nervous system. If the spinal cord is damaged, the reflex tests can help pinpoint the area (level) of spinal cord injury. Motor nerves above the injured area may be unaffected, whereas those at or below the lesion site may be unable to participate in normal reflex activity.
What are the primary structural/anatomical differences between a somatic versus a visceral reflex arc?
The muscle is the effector in somatic. Viscera is the effector in autonomic.
Some people suffer from a condition known as congenital insensitivity to pain, in which they cannot detect painful stimuli at all, yet all their motor skills are normal. Which portion of the somatic reflex arc might be defective in people with this condition?
The integration center or the sensory receptor.
(both are before motor neurons)
There is a related condition known as congenital indifference to pain, in which people can detect painful stimuli, but they do not react properly to the stimulus. Essentially, these people do not feel pain as very painful. People with this condition have normal motor function. Which portion of the somatic reflex arc might be defective in people with this condition?
The integration center
When your small intestine begins to fill with food, a signal is sent to the brainstem that initiates contraction of the smooth muscle in the abdominal wall and the movement of the food through the intestines. Is this an example of a somatic or visceral reflex arc?
Visceral reflex arc
_______ are somatic reflexes important in maintaining posture, balance, and locomotion.
Stretch reflexes
Stretch reflexes are initiated by tapping a _____, which stretches and stimulates the muscle spindles.
tendon
The inhibition of those interneurons and the antagonist muscles is called _______.
reciprocal inhibition
Stretch reflexes tend to be hypoactive or absent in cases or _______ or _______.
peripheral nerve damage or ventral horn disease
The _______ is a technique to enhance sluggish stretch reflexes.
Jendrassik Maneuver
(Clench teeth, interlock hands, look at ceiling, and when given a verbal cue, pull hands apart without letting go)
The patellar reflex (knee-jerk) assesses the _____ level of the spinal cord.
L3-L4
What muscles contract during the patellar reflex?
Quadriceps
Mental distraction and simultaneous muscle activity has what effect on the patellar reflex?
Makes the response more vigorous.
(prevents conscious inhibition by focusing on something else)
If your subjects muscle is fatigued, what effect will this have on the patellar reflex?
Less vigorous
The Achilles reflex (ankle-jerk) assesses the _____ level of the spinal cord.
S1 and S2
The biceps reflex assesses the _____ level of the spinal cord.
C5 and C6
The biceps reflex causes…
flexion of the arm
The ____ is a deep reflex causing extension of the arm in normal individuals.
triceps reflex
The triceps reflex assesses the _____ level of the spinal cord.
C7 and C8
The crossed-extensor reflex assesses the _____ level of the spinal cord.
multiple levels
The crossed-extensor reflex innervates flexors and extensors to….
maintain balance as you withdrawal from painful stimuli.
The _____ results from pain and temperature changes.
Superficial cord reflexes
Superficial cord reflexes depend on both…
-upper motor pathways
-cord-level reflex arcs
The _____ is elicited by stimulating the cutaneous receptors in the sole of the foot.
plantar reflex
Damage to the _______ (upper motor neurons) produces ______.
pyramidial tract; Babinksi’s sign
An abnormal response in which the toes flare and the great toe moves in an upward direction.
Babinksi’s sign
The plantar reflex assesses the _____ level of the spinal cord.
S1 and S2
What muscles contract during the Achilles reflex?
Gastrocnemius and Soleus
What muscles contract during the Biceps reflex?
Biceps brachii
What muscles contract during the triceps reflex?
Triceps brachii
What muscles contract during the plantar reflex?
Tibialis anterior
What are examples of pupillary reflexes?
-The pupillary light reflex
-The consensual reflex
When the light is directed into one eye, the response in that eye is the _______
direct response
Connections through the brain result in the constriction of the pupil in the other eye. This is called a _______.
consensual respnse
Is the sympathetic or parasympathetic division of the ANS active during the testing of the pupillary reflex?
Parasympathetic
The ______ is another example of reflex activity in which pupillary responses can be observed. This response occurs naturally during emotional responses
Ciliospinal or pupillodilator reflex
If the eye dilates, this is likely a response of the sympathetic division because…
It dilates to take in more visual information
Pupillary dilation is an _____ response.
ipsilateral
Define reflex
rapid, automatic responses to stimuli
Give 3 examples of somatic reflexes.
-Patellar reflex
-Plantar reflex
-Bicep reflex
Give 2 examples of autonomic reflexes.
-Visceral reflex
-Pupillary reflex
(Involves cardiac or smooth muscle or gland)
What is the protective nature of the pupillary light reflex?
Protects the photoreceptors from bright lights to prevent retinal damage
What is the protective nature of the pupillary light reflex?
What is the protective nature of the pupillary light reflex?
What is the protective nature of the crossed-extensor reflex?
Protects and withdrawals the region in pain by shifting to the other side. Maintains balance
Reaction time is the _____ between when a stimulus is presented and when you do something about it.
delay
The beginning of a race is a classical ________, where runners hear a stimulus and react to it, the response.
stimulus-response situation
Some reflexes are basic, or _____
inborn
Some reflexes are learned, or ____
acquired
What was the effect of adding a stimulus word to your subject’s reaction times?
Decreased reaction time
(effect of learning/having a cue)
Random stimuli segments
computer generates a click randomly
Fixed-interval stimuli segments
computer generates a click consistently
What overall patterns do you see in reaction time in your dominant vs. non-dominant hand
Reaction time decreased towards end of test.
What might account for these differences?
learning
The _____ is formed by the paired coxal bones and the sacrum.
Pelvic girdle
Joint in which your body weight is transferred from your spine to the pelvis
Sacroiliac joint
The space enclosed by the bones
Pelvic cavity
An oval ridge/ring running from the pubic crests posteriorly through sacral promontory, separates the true from the false pelvis
Pelvic brim
The pelvic brim also defines the ____
pelvic inlet
The inferior margin of the true pelvis is the ______
pelvic outlet
Each coxal bone is formed from the fusion of 3 bones
-Ilium
-Ischium
-Pubis
The ability to locate L4 is essential for performing a _____, a procedure in which the clinician inserts a needle into the vertebral canal of the spinal column directly superior or inferior to L4 and withdraws cerebrospinal fluid.
lumbar puncture (spinal tap)
The ____ is the most easily dislocated when it is flexed and medially rotated
hip
Trauma or arthritic destruction of the interior hip joint may reduce mobility or cause pain. Treatment is
hip replacement
The distal element of a joint is deviated laterally
Valgus deformity
(Knock-kneed)
The distal element of a joint is deviated medially
Varus deformity
(Bow-legged)
Abducts, extends, and laterally rotates thigh
Gluteus maximus
(Used in running, climbing, and rising from seated position - not walking)
Abducts and medially rotates thigh/femur; assists in free leg swing when walking
Gluteus medius
The gluteal region is a major site for administering
intramuscular injections
Injections are most often applied to the
gluteus medias
Infants and toddlers receive intramuscular shots in the
vastus lateralis
Steadis pelvis on femur head. Hip abduction and medial rotation of thigh
Tensor fascia lata
Adduct and medially rotate thigh
Adductor longus, brevis, and magnus
Flexes, abducts, and laterally rotates thigh
Sartorius
Adducts and medial rotates hip and flexion at knee
Gracilis
A 3-sided depression that lies on the anterosuperior surface of the thigh
femroal triangle
The _____ descends through the femoral triangle
femoral artery
As a group, powerful extensors of lower leg at knee, used in running, climbing, and jumping
-Quadriceps femoris:
-rectus femoris
-vastus intermedialis
-vastus lateralis
-vastus medialis
The quadriceps femoris muscle can be used. to test the _____ in cases of suspected nerve damage
femoral nerve
These 3 muscles located in the posterior of the thigh cross both the hip and knee joints and are the prime movers of thigh extension and knee flexion
Hamstrings:
-Biceps femoris
-Semimembranosus
-Semitendinosus
common sport injuries especially when running hard
pulled hamstrings
The diamond-shaped hollow region that contains the popliteal artery
popliteal fossa
The diamond-shaped hollow region that contains the popliteal artery
popliteal fossa
Superficial muscle of pair. Plantar flexes foot when leg is extended; weakly flexes knee when foot is dorsiflexed
Gastrocnemius
Deep to gastrocnemius. Plantar flexes foot
Soleus
Largest tendon in body; attachment for gastrocnemius and soleus
Calcaneal (Achilles) tendon
Superficial muscle of anterior leg; parallels tibia; prime mover of dorsiflexion of foot. Also inverts foot
Tibialis anterior
Superficial lateral muscle of leg over fibula. Plantar flexes and everts foot
Fibularis (Peroneus) longus
Hairline fractures resulting from repeated shocks or impacts to a bone
Stress fracture
Overstretched ligaments resulting in tearing of the collagen fibers
Sprain
Pain in the anterior compartment of the leg (tibia) caused by irritation and swelling of the tibialis anterior muscle, typically following unusual or extreme exercise
Shin splints
painful muscle spasms resulting from strain or contusions (tearing of the muscle with bleeding and pain). Common injury to quadriceps muscles in football players.
Charlie Horse
Overstretching and or tearing of the fibrous band connecting the heel to the toes and supporting the arch of the foot. Common cause of pain in heel
Plantar Fascitis
Commonly called a pulled muscle. Excessive stretching and tearing of the muscle due to overuse or improper use
Strain
Damage to the deep fibular nerve, a branch of the sciatic nerve, paralysed the muscles of the anterior compartment of the lower leg resulting in the inability to dorsiflex the ankle, causing
foot drop
What is the name of the articulation between the two pubic bones?
pubic symphysis
The head of the femur articulates with the
Acetabulum of the pelvis
What are the names of the two blunt projections near the proximal end of the femur?
Greater and lesser trochanter
The lateral condyle of the femur articulates with the articular surface of the lateral condyle of the
tibia
The shin bone is also known as the
tibia
The lateral bone of the lower leg
fibula
