Wk5 Simple Reflexes Flashcards
What is a reflex?
Neural reflexes are stereotyped, involuntary reactions of the CNS to specific sensory input
What are the types of reflexes?
Stereotyped - characteristic = same every time
Involuntary - conscious thought not required
Rapid
How to test reflexes?
Pupillary - pupil with light
Deep tendon flexes - knees etc
What are general functions fo reflexes?
Protective e.g limb withdrawal (somatic & skeletal)
Postural control e.g. walking (somatic & skeletal)
Homeostasis e.g. blood pressure —> smooth muscle
What is a reflex arc?
Sensory receptor —> afférent —> integration —> efferent —> effector
What does integration do?
Contains interneurones Not relay neurones CNS - spinal cord, brain stem nuclei Enteric nervous system Interneurones communicate with efferent neurones
What are muscle spindles?
Specialised set of muscle fibres that are so perfectly organised if a change occurs it is detected
What are the neural components?
Sensory receptors
Afferents - sensory neurones
Integration - interneurones & modulation
What are the neural components 2.0?
Efferent neurones
“Motor neurone”
- innervate effectors
Effectors
- glands, muscle
- appropriate response
What are myotatic simple stretch reflexes?
- posture
- adjust degree of muscle contraction
- sensory receptors
Myotatic - simple stretch reflexes
- adjust degree of skeletal muscle contraction
- posture
—>
Sensory receptors = propireceptors - look at state of body
Monosynaptic
Only one synapse between neurones
How does a muscle spindle work?
Weight applied to increase stretch
Excitatory neurotransmitter released (ACh) causes muscle contraction
Knee jerk reflex
Moves tendon, stretching spindle and passing information along
2 pathways allowing for opposite movements of antagonistic pairs
Innervates skeletal muscle
Golgi tendon organ
Increased contraction = increased GTO activation
Function of golgi
Prevents damage due to overwork
Free control of muscle tension
