Midterm 2

Question 1

Define exteroception, proprioception and interoception.

Which has the most and the least influence on performance?

Answer 1

Exteroception: Information obtained from the external environment. Most influence on performance.
Proprioception: Information coming from within the body.
Interoception: Involves functions within the body. Least influence on performance.

Question 2

What source of sensory information helps detect spatial and temporal aspects of our own movements in our environment?

Answer 2

Exteroceptive information; Vision & Audition

**Also allows for anticipation

Question 3

Which source of sensory information is important for posture and balance?

Answer 3

Proprioception & Kinesthesia

Important internal receptors provide neuromuscular system with information.

Question 4

What is the function of the vestibular apparatus? What about the semi-circular canals?

Answer 4

Vestibular apparatus: detects movements of the head. Sensitive to it’s orientation with respect to gravity.
Semicircular canals: Each oriented in a different plane, with fluid that moves as the head moves.

Question 5

Where are muscle spindles located? What is their function?

Answer 5

Muscle spindles are located within the muscle, parallel to muscle fibers.
They provide information regarding joint position (especially at end of ROM), and muscle length/ stretch.

Question 6

What are intrafusal fibers? What does excitation of these fibers cause?

Answer 6

Intrafusal fibers are skeletal muscle fibers that detect the amount/ rate of change in length of a muscle. They constitute the muscle spindle, and are innervated by both sensory (afferent) and motor (efferent) fibers.
Excitation of intrafusal fibers elicits a protective myotatic reflex to prevent overstretching.

Question 7

What are GTOs?

Golgi Tendon Organs

Answer 7

GTOs are located between the muscle and tendon. They are inhibitory in nature, signaling the level of force in parts of the muscle, and ensuring the tendons do not rip off the bone.

Question 8

Do muscles exert force on to bone?

Answer 8

No. Muscles act through tendons.

Question 9

Define the function of joint receptors and cutaneous receptors.

Answer 9

Joint receptors provide information on joint position, located in joint capsules.
Cutaneous receptors provide haptic information, detecting pressure, temperature, and pain.

Question 10

Define passive and active movements.

Answer 10

Passive movements: Being guided through the movement, not actively producing the movement.
Active movements: Actively producing the movement.

Question 11

Are orthopedic braces primarily harmful or beneficial? Why?

Answer 11

They block important sensory information and change perception of movement. Can be harmful.

Question 12

Define closed loop control. What type of movements is it mainly used for?

Answer 12

Utilizing feedback/ knowledge of current state in order to inform future decisions.
Error detection and correction in order to maintain desired state.
Used for control of slow and deliberate movements.

Question 13

Define what comparator, effective, executive, and feedback do in closed loop control.

Answer 13

Comparator: Senses differences between actual and desired sensations.
Executive: Command/ control center. Makes decisions.
Effector: Carries out the movement.
Feedback: Informs decisions. Do desired and actual sensations differ? Should we stay the same or change?
**Error is detected when actual and desired states differ.

Question 14

What is the process of closed loop control?

Answer 14

Input, Executive (+ Desired state), Effector, Output, Feedback, Actual state, Comparator, Error…

Question 15

What steps can executive and effector be broken down into?

Answer 15

Executive: Stimulus id, response selection, response programming.
Effector: Motor program, spinal cord, muscles.
**Neuromuscular system as well as musculoskeletal.

Question 16

Where does feedback come from?

Answer 16

Effector provides proprioceptive feedback (muscle length/ force, body/ joint position).
Output provides exteroceptive feedback (vision, audition).

Question 17

Are the stages of closed loop control sequential?

Answer 17

Yes. Sequential and non-overlapping.

Question 18

Which two sources of information are required for error detection?

Answer 18

Representation of the sensory qualities of the intended action and of the actual action. (Feedforward and feedback)
**Feedforward is using previous results to inform performance.

Question 19

Define sensation and perception.

Answer 19

Sensation: neural activity triggered by a stimulus activating a sensory receptor.
Perception: Process in the CNS. Meaning is attached to sensory output. Involves integration, selection, organization and interpretation of information.

Question 20

What are afferent senses?

Answer 20

Sensory pathways leading away from the skin.

Question 21

Define the cornea, iris, lens, and retina.

Answer 21

Cornea: Clear outer layer of the eye.
Iris: Controls amount of light that enters the eye.
Lens: Controls focus of light.
Retina: Converts light into neural impulses.

Question 22

Define the pupil, optic nerve, and visual cortex.

Answer 22

Pupil: Controls intensity of light hitting the lens.
Optic nerve (CN II): Carries neural impulses to the brain.
Visual cortex: Receives and processes visual information.

Question 23

What is the snellen scale?

Answer 23

Measure of visual acuity (test distance/ letter size).

ex. 20/20, 6/6… etc.

Question 24

Define focal and ambient vision.

Answer 24

Focal vision: What is being focused on consciously.

Ambient vision: All visual information being acquired.

Question 25

Define optical flow, cerebral akinetopsia, and the ventral and dorsal pathways.

Answer 25

Optical flow: Visual perception of motion, timing, perception, direction.
CA: Motion blindness.
Ventral pathways: Front. Perception of objects. Determining what they are.
Dorsal pathways: Back. Determining where the object is. Movement.