S1_L1: Reflexes Flashcards
This is an involuntary motor output and nearly instantaneous movement in response to a stimulation.
Reflex
TRUE OR FALSE: Reflexes are symmetrical. It does not receive nor need conscious thought.
A. Both statements are true
B. Both statements are false
C. Only the 1st statement is true
D. Only the 2nd statement is true
A. Both statements are true
Reflex responses happen (1)_______ to prevent us from being (2)_______
- automatically
- harmed
NOTE: it is for self-preservation
Reflexes are (1)_______ and can be modified to perform (2)_______ tasks and maintain (3)_______
- adaptable
- motor
- balance
Source: Ganong (Chapter 12)
Determine the number of synapses of a reflex
- ankle reflex
- stretch reflex
- deep tendon reflexes
- withdrawal reflex
- triceps reflex
A. Monosynaptic reflex
B. Polysynaptic reflex
- A
- A
- A
- B
- A
This is the basic unit of integrated reflex activity
Reflex Arc
Source: Ganong (Chapter 12)
An activity in the reflex arc generates (1)_______ action potentials in the (2)_______ nerve
- all-or-none
- afferent
TRUE OR FALSE: Reflex activity is specific in that a particular stimulus elicits a particular response. Ascending inputs from higher brain regions play an important role in modulating and adapting spinal reflexes.
A. Both statements are true
B. Both statements are false
C. Only the 1st statement is true
D. Only the 2nd statement is true
Source: Ganong (Chapter 12)
C. Only the 1st statement is true
Note: It is descending inputs
Activity in the reflex arc starts in a (1)______ with a (2)______
- sensory receptor
- receptor potential
Source: Ganong (Chapter 12)
TRUE OR FALSE: The number of action potentials is proportional to the size of the receptor potential.
True
Somatic reflex - involve the (1) _______ muscles, while autonomic reflex - involve the (2)_______ muscles
- skeletal
- smooth
_______ is the integrative area for the cord reflexes
Cord gray matter
Source: Guyton (Chapter 55)
TRUE OR FALSE: When tendon reflex are tested, limbs on each side should be flexed to 90 degrees and strike for 5 times.
False
It must only be placed in identical positions and elicited in the same manner.
TRUE OR FALSE: Receptor potential’s magnitude is proportional to the strength of the stimulus
True
Tendon reflexes are elicited because of change in (1)_____ or (2)_____ tension in a muscle
- length
- tension
You tested a pt’s knee jerk with him sitting on the edge of a bed, with his feet dangling. With a reflex hammer, you tap his patellar tendon. As a result, his leg kicked out, then immediately came to a rest.
What grade will this response be given?
2+ (normoreflexia)
You tested a pt’s knee jerk with him sitting on the edge of a bed, with his feet dangling. With a reflex hammer, you tap his patellar tendon. As a result, his leg kept swinging out repetitively.
What grade will this response be given?
4+
NOTE: This is a very brisk, with clonus response (repetitive jerky movement noted after elicitation of reflex)
You tested a pt’s knee jerk with him sitting on the edge of a bed, with his feet dangling. With a reflex hammer, you tap his patellar tendon. However, tghe leg does not respond.
What grade will this response be given?
0 (areflexia)
TRUE OR FALSE: Tendon reflexes can excite either GTO or muscle spindle, or both at the same time
True
Match the following neurons/ cells to its corresponding description.
- located in the anterior horns of the spinal cord
- present in all areas of the cord gray matter
- small and highly excitable, often exhibiting spontaneous activity and capable of firing as rapidly as 1500 times per second
A. Anterior Motor Neurons
B. Interneurons
C. Renshaw Cells
D. A & B
E. A & C
- E
- B
- B
Match the following neurons/ cells to its corresponding description.
- spinal glycinergic inhibitory interneurons
- directly innervate the skeletal muscle fibers
- where almost all sensory signals from spinal nerves or signals from the brain are transmitted first
A. Anterior Motor Neurons
B. Interneurons
C. Renshaw Cells
D. A & B
E. A & C
- C
- A
- B
Source: Guyton (Chapter 55)
Interconnections among the (1)_____ and (2)______ are responsible for most of the integrative functions of the spinal cord
- interneurons
- anterior motor neurons
What are the 2 types of anterior motor neurons?
alpha motor neurons and gamma motor neurons
type A alpha (Aα) motor nerve fibers innervate (1)______ fibers, while type A gamma (Aγ) motor nerve fibers innervate (2)_______ fibers
- extrafusal
- intrafusal
Intrafusal fibers constitute the middle of the _______, which helps control basic muscle tone.
muscle spindle
This is when the stimulation of each motor neuron tends to inhibit adjacent motor neurons
Lateral inhibition
Which of these utilizes lateral inhibition?
A. Anterior Motor Neurons
B. Interneurons
C. Renshaw Cells
C. Renshaw Cells
These fibers run from one segment of the cord to another and provide pathways for the multi segmental reflexes
Propriospinal Fibers
What tract carry instantaneous information from both the muscle spindles and the Golgi tendon organs directly to the cerebellum?
Dorsal spinocerebellar tracts
TRUE OR FALSE: Both the GTO and muscle spindle are almost entirely for the purpose of extrinsic muscle control. These operate almost completely at a subconscious level.
A. Both statements are true
B. Both statements are false
C. Only the 1st statement is true
D. Only the 2nd statement is true
D. Only the 2nd statement is true
*intrinsic muscle control
Determine whether the description is for a muscle spindle or for GTO.
- excitatory in nature
- inhibitory in nature
- sensitive to stretch
- sensitive to tension or rate of change of tension
- distributed all throughout the muscle belly
A. Muscle Spindle
B. Golgi Tendon Organ
- A
- B
- A
- B
- A
The following statements are true about muscle spindles, EXCEPT:
A. Deeply ingrained with nerve endings
B. Spindle-like or fusiform-shaped muscle sensory receptor
C. Send information to the nervous system about muscle length or rate of change of length
D. Central portion functions as a sensory and motor receptor
E. None of the above
D. Central portion functions as a sensory and motor receptor
NOTE: Only as a sensory receptor
TRUE OR FALSE: Muscle spindles provide information on joint position.
True
NOTE: This is because changes in muscle length are associated with changes in joint angle
Source: Ganong (Chapter 12)
The central portion of the muscle spindle is _____
A. Contractile
B. Non-contractile
B. Non-contractile
What are the 2 types of sensory endings at the central receptor area of the muscle spindle?
- Primary afferent ending/Annulospiral ending
- Secondary afferent ending/FlowerSpray ending
Determine the type of sensory endings at the central receptor area of the muscle spindle.
- Type II fibers
- Encircles the central portion of intrafusal fibers
- Faster nerve conduction velocity
- Excited by both the nuclear bag intrafusal fibers and the nuclear chain fibers
- Only excited by the nuclear chain fibers
A. Annulo-spiral ending
B. Flower-Spray ending
- B
- A
- A
- A
- B
How fast is the nerve conduction velocity of the annulo-spiral endings?
70-120m/s
What kind of nerve fibers do the annulo-spiral endings ahve?
Type Ia fibers
TRUE OR FALSE: Both branches of the annulo-spiral endings innervate the nuclear bag and nuclear chain.
False.
NOTE: One branch innervates nuclear bag. The other branch innervates nuclear bag and nuclear chain.
Determine the muscle spindle intrafusal fiber.
- has 2 subtypes: dynamic and static
- one to three in each spindle
- three to nine in each spindle
- innervated by type Ia and II
- nuclei aligned in a chain throughout the receptor area
A. Nuclear bag muscle fibers
B. Nuclear chain fibers
- A
- A
- B
- B
- B
The polar ends of a muscle spindle is contractile because of the presence of (1)____ and (2)_____ filaments.
- actin
- myosin
Gamma efferent fibers are _____
A. Inhibitory
B. Excitatory
C. Both
B. Excitatory
Stretching the muscle spindles (1)______ the rate of firing, whereas shortening the spindle (2)_______ the rate of firing
- increases
- decreases
TRUE OR FALSE: Spindles can send to the spinal cord either positive signals to indicate stretch or negative signals to indicate that the muscle is unstretched
True