module 5 - 13.8 reflexes Flashcards
what are the features of a reflex/reflex action?
- has a specific stimulus
- is involuntary
- has nearly instantaneous response
- done to prevent damage to body
- involves neural pathway called reflex arc (doesn’t involve brain)
what are the human reflexes needed to know?
- knee-jerk/patellar reflex
- blinking reflex
what does a receptor cell transduce during a reflex?
mechanical energy
where does the nervous impulse travel during a reflex?
- along the sensory neurone that enters and spinal cord via the dorsal root ganglion
- then relay neurone forms synapses with relay neurone, which leaves spinal cord via ventral root
what is the spinal cord?
long, thin tubular structure made up of nervous tissue
what does the spinal cord do to the medulla oblongata?
extends medulla oblongata in brainstem to lumbar region of vertebral column
what does the vertebral column do?
it encloses the central canal of the spinal cord which contains cerebrospinal fluid
what are the functions of the spinal cord?
- transmission of nervous impulses from the motor cortex to the effectors
- transmission of nervous impulses form the motor cortex to the effectors
- coordinating reflexes
- controlling motor instructions for rhythmic movement e.g. walking
what type of reflex is the knee-jerk reflex?
spinal reflex that tests the functioning of the spinal cord
what is the knee jerk/patellar reflex?
striking below the patellar or knee cap, with a reflex hammer stretches the tendon of the quadriceps
what is the blinking reflex?
- cranial reflex involving PONS in the lower brain stem
- occurs in response to external stimulus (e.g. contact with cornea/loud sounds)
- fast reflex
- reflex is consensual because both eyelids blink
how do reflexes increase an organisms chance or survival?
- being involuntary
- being innate
- fast
- controlling actions that are common place
