Christopher Reeve as Superman

Christopher Reeve as a super man

In a horseback riding accident.. Christopher Reeve severely damaged his ascending and descending spinal tracts at C3. He was not able to breathe on his own He was not able to move his arms or legs He was not able to feel his arms or legs

But he could… See, hear, taste Feel and move his face and neck Beat his heart Digest food Process waste Have an erection How?

What we have studied so far? The somatic part of the nervous system has neurons that connect only to SKELETAL muscles But skeletal muscles do not run the heart or digestion.

We place neurons into groups based on their function. Some receive information and pass it to the brain. Others send information from the brain to glands and muscles. Figure 11.2 Central nervous system (CNS) Brain and spinal cord Integrative and control centers Peripheral nervous system (PNS) Cranial nerves and spinal nerves Communication lines between the CNS and the rest of the body Parasympathetic division Conserves energy Promotes house- keeping functions during rest Motor (efferent) division Motor nerve fibers Conducts impulses from the CNS to effectors (muscles and glands) Sensory (afferent) division Somatic and visceral sensory nerve fibers Conducts impulses from receptors to the CNS Somatic nervous system Somatic motor (voluntary) Conducts impulses from the CNS to skeletal muscles Sympathetic division Mobilizes body systems during activity Autonomic nervous system (ANS) Visceral motor (involuntary) cardiac muscles, smooth muscles, and glands Structure Function Sensory (afferent) division of PNS Motor (efferent) Somatic sensory fiber Visceral sensory fiber Motor fiber of somatic nervous system Skin Stomach Skeletal muscle Heart Bladder Parasympathetic motor fiber of ANS Sympathetic motor fiber of ANS

Different neurons go to organs and glands These neurons are part of the ANS Or AUTONOMIC part of the Nervous System

Functions of ANS These nerves act on glands, cardiac muscle, and smooth muscle They do NOT act on skeletal muscles These nerves control : HR, BP, temp, digestion, waste elimination

Autonomic nervous system Nerves called SYMPATHETIC nerves Adjust body function for excitation Increase heart rate Turn off digestion Nerves called Parasympathetic nerves Adjust body function for resting and digesting Decrease heart rate Turn on digestion

Anatomy of the ANS The sensory pathway of the ANS uses the spinal nerves to enter the spinal cord and the sensory cranial nerves to enter the brainstem.

Anatomy of the ANS The MOTOR pathway to the glands, heart, and smooth muscle. This pathway needs TWO neurons to get there (instead of ONE like the PNS) The motor neuron leaving the spinal cord synapses with another neuron in a GANGLIA. This neuron that sends an axon to the glands, heart or smooth muscle.

Somatic vs autonomic Notice that the somatic nervous system has only one motor neuron going to an effector. Notice that the autonomic nervous system (sympathetic and parasympathetic) needs 2 motor neurons to reach an effector.

ANS: Sympathetic part Prepares the body for physical activity (exercise, excitement, embarrassment, emergency) Increased heart beat To provide more oxygen and glucose to cells of body releases blood glucose from storage To provide more sugar to cells of the body Increases air flow to lungs To allow more oxygen to be used for ATP production Increases blood flow to heart and skeletal muscles To allow more ATP production

ANS: Parasympathetic part Has a calming effect on body functions that allow normal metabolic process to occur (digestion, defecation, diuresis) Starts salivation to break down food Increases stomach intestinal movements Starts urination and defecation To eliminate wast Stores food that has been eaten For use when needed later Slows heart rate Less oxygen and nutrients needed by body while resting

Sympathetic &Parasympathetic ANATOMY Compare the places they leave the CNS! Sympathetic? Through spinal cord to ganglia, then to effectors. Parasympathetic? Mainly avoids spinal cord by using cranial nerves, and goes to effectors.

Sympathetic and Parasympathetic ANATOMY Compare the organs that the nerves extend towards. (p571 and 575) Which are the same? Different?

Dual innervation Antagonistic effects examples: Parasympathetic: slows heart down Sympathetic: speeds heart up Parasympathetic: increases digestive motility Sympathetic: decreases digestive motility

Single innervation Sympathetic nerves Sweating Arector pili muscles (hair standing on end) Constricts blood vessels, , blood pressure Adrenalin release Decreased urine output

In a horseback riding accident.. Christopher Reeve severely damaged his ascending and descending spinal tracts at C3. He was not able to breathe on his own He was not able to move his arms or legs He was not able to feel his arms or legs

But he could… See, hear, taste Feel and move his face and neck Beat his heart Digest food Process waste Have an erection How?

Through visceral reflexes! Much of running the organs is reflex activity digesting food beating heart raising and lowering blood pressure Some visceral reflexes occur through cranial nerves Some visceral reflexes occur through the spinal nerves