REFLEX ACTIVITYCHAPTER 13 PART 4

Anatomy &Physiology

Reflexes

much of what body must do every day is programmed as reflexesa rapid, predictable, & involuntary

responseoccur over neural pathways called

reflex arches

Reflexes

1. Inborn or Intrinsic unlearned, unpremeditated , involuntary designed to keep you in homeostasis w/out having to

think may or may not be aware of it

2. Learned or Acquired result of practice or repetition

2 Types Reflexes

1. Autonomic reflexes: regulate activity of smooth muscles, heart, glands examples: salivating when smell Thanksgiving dinner cooking pupils dilating/constricting with change in amount

light2. Somatic reflexes:

stimulate skeletal muscles examples: pull hand away from hot stove

5 Parts to a Reflex Arc

1. Receptor: site of stimulus 2. Sensory neuron

afferent impulses to the CNS3. Integration center

Monosynaptic: 1 synapse sensory motor neuron Polysynaptic: multiple synapses with interneurons

4. Motor neuron efferent impulses to effector organ

5. Effector muscle fiber or gland that responds to efferent

impulse

5 parts of Reflex Arches

Spinal Reflexes

somatic reflexes mediated by spinal cord (no involvement of brain)

mostly, remain intact even if brain not functioning as long as spinal cord is intact

most of these do send signals to brainclinically important to asses condition of the

nervous system exaggerated, distorted of absent reflexes indicate

degeneration or pathology

Spinal Reflexes

What the Nervous System Needs to Know About Skeletal Muscle so there is Coordination1. length of muscle

muscle spindles2. amount of tension on the muscle

tendon organs

Both called proprioceptors important role in spinal reflexes provide essential feedback to cerebral cortex &

cerebellumhttps://www.youtube.com/watch?v=obM1uHucAbM

Anatomy of Muscle Spindle

The Stretch Reflex

makes sure muscle stays at length set by motor cortex

important for maintaining muscle tone adjusts it reflexively sustains upright posture in large muscles of back

https://www.youtube.com/watch?v=nuzx5WJc-mE

Stretch Reflexes

Autonomic Reflexes

https://www.youtube.com/watch?v=krhTPjle7S8

Autonomic Reflexes

Pupillary Reflexes