CONTROL OF UPRIGHT POSTURE AND BALANCE Flashcards
skeleton can stand erect against gravity without the coordinated support of muscle activity
T/F
F
——-and——- of the skeleton are essential in maintaining posture and uprightness
Long bones
many jointed spine
Anti-gravity muscles are controlled by
——, and ——- mechanisms connected to neural networks of the——- and——-
Brain
reflex
brainstem
spinal cord
——and—— reflex are active in posture control
stretch
extensor
to maintain upright posture and balance, the body’s centre of gravity must be maintained ——-
over the body’s base
human beings are tall structures that balance on a relatively—— base, with center of gravity just above the——- which is quite——
small
pelvis
high
FOR STABILITY
- centre of gravity must be kept within the——— that the—— provide
- once the center of gravity has been moved beyond this point, the body would fall unless———
- people can operate under conditions of unstable equilibrium because———
base of support; legs
one leg is shifted to broaden the base of support
complex interacting postural reflexes maintain their balance
Postural Reflexes
- Afferent pathways
- ____
- _____
- receptors involved in____
- Efferent pathways
- ____neurons to____ muscles
- Integrating centers
- neural network in—— and——-
- centers in the brain that form an ———of the body’s——, it’s support conditions and its orientation with respect to vertical
eyes
vestibular apparatus
proprioception
alpha motor
skeletal
brainstem
spinal cord
internal representation
geometry
INTERNAL REPRESENTATION
- 2 purposes
- provides a———-and for ———
- contributes to——- through the—— controls involved in maintaining upright posture
reference frame for the perception of the body’s proprioception; planning actions
stability; motor
CROSSED EXTENSOR REFLEX :
-important component in the—— mechanism of locomotion
stepping
afferent input is necessary for optimal postural adjustments and interfering with any one of them causes the individual to topple over
T/F
F
blind people maintain their balance quite well with only a slight loss of precision
T/F
T
people whose vestibular mechanisms have been destroyed have alotttt of disability in everyday life even if their visual and somatic receptors are functioning
T/F
F
-people whose vestibular mechanisms have been destroyed can (with rehabilitation), have very little disability in everyday life as long as their visual and somatic receptors are functioning
postural control mechanisms are
flexible or rigid
Ineffective or effective
highly adaptable or only adaptable to a little extent
Flexible
Effective
highly adaptable
WALKING
-requires the coordination of about 20 of muscles, each activated to a precise degree at a specific time
T/F
F
Over 100
Walking is brought about by linear movements and alternating in nature
T/F
F. Cyclical movements
Walking movements are brought about by networks of interneurones in the——- at the —-level
-the interneurones network coordinate the—- of the various neuron pools that controls the appropriate muscles of the arms, shoulders, trunk, hips , legs and feet
spinal cord
local
output
INSTABILITY
In the absence of command inputs from descending fibers,the complex spinal cord can produce the rhythmic movements of limbs
T/F
T
under normal conditions, neural activation of walking occurs in the——-,———,——-, and——-
cerebral cortex
cerebellum
brainstem
spinal cord
MIDDLE AND HIGHER LEVELS OF MOTOR CONTROL HIERARCHY ARE NECESSARY FOR postural control
T/F
T
———- are required for voluntary override commands(like breaking strides to jump a puddle)
MIDDLE AND HIGHER LEVELS OF MOTOR CONTROL
MIDDLE AND HIGHER LEVELS OF MOTOR CONTROL are not necessary in adaptations to the environment (like walking across a stream or unevenly spaced stones
T/F
F
damage to even small areas of the middle and higher motor controls can cause marked disturbances in gait
T/F
T
sensorimotor areas are the ——— and ———- cortex
primary motor cortex and somatosensory cortex
List the Postural and locomotion reflexes
(1) ——— reflex
(2) ———reflexes
Positive supportive reaction
Cord righting
Postural and locomotion reflexes
Positive supportive reaction
- pressure on the footpad of a——- animal causes——-
- reflex is used to ———position
decerebrate
extension of the limb against the pressure
support animal in a rigid
Cord righting reflexes
- when a—— cat is laid on its side:
- it willl make——— that indicates that it’s trying to ———position showing that complicated reflexes are associated with posture
spinal
incoordinate movements
raise itself to standing
———-is the first postural reflex to develop and is present by——— of age.
Positive supportive reaction reflex
3 to 4 months
Spinal animal
- spinal cord is transected at the—— so that ——-still remains intact
- spinal toad, cut the—— behind the——- or a——- to destroy the——
- this results in symptoms of——
neck; most of the cord
head; tympanic membrane; single pith; brain
spinal shock
When a specimen becomes spinal ,there is X loss of reflex activity for—— in cats,—— in humans
X is complete or partial??????
Complete
days
months
During recovery from spinal shock in a newly spinal animal, when the reflexes return, they are no longer———- and ———normal patterns. Eg a light touch on the foot can cause———-
-excitability of motor neurons ultimately becomes—— than normal , causing particular groups of muscles to——- continuously
under the influence of the brainstem
Do not follow
activation of all flexor muscles of the body
more greater
contract
Decerebrate animal
- brain is transected above the——— and results in———(aka ——-)
- in frogs, cut the—— behind the——
- by doing this,—— inputs from cortex and—— to——— are removed
- alpha and gamma antigravity motor neurons are subjected to intense——-
- firing of gamma motor neurons activates the—— causing——- discharge of the group—- afferent fibers
pontine medullary reticular formation
Decerebrate rigidity; spasticity
head; eyes
inhibitory; cerebellum; reticular formation
excitation
gamma loop; increased ;1a
DECORTICORTICATE/____ PREPARATION
- due to removal of——-
- ____is intact and can:
- regulate body temp(intact____)
THALAMIC
Cerebral hemispheres
thalamus
hypothalamus
In a DECORTICORTICATE animal, movement doesn’t occur
T/F
F
Occurs but poorly.
In a DECORTICORTICATE animal movement is initiated by the—— pathways
*sensations are_____, especially—- and——
extrapyramidal
crudely appreciated; pain; temperature
decorticate rigidity is a——- rigidity due to———- areas
moderate
loss of frontal inhibitor
destruction of cortical association areas enhances—— emotions which are usually——by this areas.
primitive
suppressed
exhibit sham rage is seen in DECORTICORTICATE specimens
T/F
T
Which usually has a worse prognosis
Decerebrate or decorticate
Decerebrate
decorticate causes flexion in____ and extension in _____
Decerebrate causes flexion in____ and extension in _____
Arms
Legs
Extension in all 4
