Lab Quiz

Know which nerve triggers the dive reflex

trigeminal nerve

The brainstem then sends efferent (motor neurons) signals via the
vagus nerve (& other pathways) to target organs

Know the different responses of the dive reflex

• Parasympathetic nerves reduce heart rate and gastric mobility.

  • -  The vagus nerve: bradycardia (heart rate <60BPM)

  • -  Slower HR conserves oxygen

• -  Sympathetic nerves will cause splenic contractions and peripheral vasoconstriction.

How does an increase in motor units increase contraction force? Is there a limit to this (i.e., is there a point at which all possible motor units can be recruited?)

Maximal Stimulus: Activates all motor units to produce maximum contraction force. A muscle under maximal contraction stimulus can only contract for a short time

complete vs unfused tetanus

• Incomplete Tetanus: Multiple action potentials leading to complete tetanus.

• -  Complete Tetanus: Multiple and rapid action potentials causing muscle tissue to fully

  contract and seize up.

Different parts of a muscle twitch (latency, contraction, relaxation), where are they on the muscle twitch

• Latency phase starts from the action potential and ends when the muscle begins to contract.

• -  Contraction phase is the time it takes for the muscle to contract. This is the shortest phase.

• -  Relaxation phase is the time it takes for the muscle to relax. This is the lonest phase.

What ion is released from t-tubules that triggers sliding of myosin and actin?

calcium

reflex arc

intrinsic vs learned

In= inborn, ex dive reflex

Learn= acquired

somatic vs autonomic

som= skeletal muscle, patellar reflex

auto= smooth muscle, glands ; pupillary reflex

cranial vs spinal

cran= requires brain input, blushing

spin = no input, plantar reflex

monosynaptic vs polysynaptic

mono= A/E neuron synapse is integration center, patellar reflex

poly= 1+ interneurons as integration center, flexor reflex