Nervous System Flashcards
What are the two nervous system branches?
Central - brain and spinal cord
Peripheral - cranial and spinal nerves
What are the branches of the Peripheral NS?
Enteric - smooth muscle of gut
Somatic - skeletal muscle
Autonomic - smooth muscle of heart and glands
What type of neurons are found in the somatic NS?
somatic motor (efferent) and somatic sensory (afferent)
somatic motor (efferent) vs. somatic sensory (afferent)
somatic motor (efferent) - from brain to skeletal muscle somatic sensory (afferent) - from skeletal muscle to brain
What are the branches of the autonomic ns?
sympathetic and parasympathetic ns
Goal of sympathetic ns
FIGHT OR FLIGHT
increase alertness, energy, and stress management
What happens when SNS is activated?
- increase HR and BP
- decrease urine and digestion
- increase sweating
- dilate pupils
- breakdown fuels for energy
What are the target organs of the SNS?
all organs chest down
Goal of parasympathetic ns
REST AND DIGEST
promote digestion and absorption
What happens when PNS is activated?
- decrease HR and BP
- increase urine and digestion
- increase hormone secretion
- constriction of pupils
what are the target organs of the PNS?
organs in the head/neck and sacral area
What are the main cranial nerves affecting the parasympathetic ns?
Oculomotor (III), facial (VII), glossopharyngeal (IX), and vagus (X)
List the function of the following cranial nerves…
Oculomotor (III), facial (VII), glossopharyngeal (IX), and vagus (X)
Oculomotor (III) - eye movement
facial (VII) - salivation
glossopharyngeal (IX) - salivation and swallowing
vagus (X) - 80% of all parasympathetic activity
What nuclei make up the vagus (X) nerve?
Dorsal motor nucleus, nucleus tractus solitarius, and nucleus ambiguus
What nerve fiber emerges from the dorsal motor nuclei, what does it innervate, and what is the function?
Visceral motor (efferent) neural fiber - visceral abdomen and thorax - DIGESTION
What nerve fiber emerges from the nucleus tractus solitarius, what does it innervate, and what is the function?
Visceral sensory (afferent) neural fiber - visceral abdomen and thorax - Fight and flight
What nerve fiber emerges from the nucleus ambiguus, what does it innervate, and what is the function?
Branchial (face) efferent motor neural fiber - pharynx, larynx, esophagus, and heart - SOCIAL ENGAGEMENT
What are the two types of neurons in the autonomic NS?
autonomic motor (efferent) and autonomic sensory (afferent)
Autonomic motor (efferent) vs. autonomic sensory (afferent) neurons
autonomic motor (efferent) - brain to non-skeletal (smooth cardiac) muscle autonomic sensory (afferent) - non-skeletal (smooth cardiac) muscle to brain
What type of neurons make up the autonomic motor (efferent) neurons?
sympathetic and parasympathetic motor neurons
Explain the 2 types of sympathetic motor neurons
- Preganglionic myelinated –> ACh released at autonomic ganglion –> postganglionic unmyelinated –> NE released at adrenergic receptors on cardiac smooth muscle
- preganglionic myelinated –> ACh released at adrenal medulla –> NE and E released at adrenergic receptors on blood vessels
When is NE a transmitter?
when it is released into tissue
When is NE and E a hormone?
when they are released into the blood stream
What are the two types of adrenergic receptors innervated by sympathetic motor (efferent) neurons?
alpha and beta adrenergic receptors
Alpha vs. beta adrenergic receptors
alpha - found in smooth muscle of arterioles and bladder –> constriction
beta - found in cardiac bronchioles and liver –> increased metabolism
Explain the type of parasympathetic motor (efferent) neurons
- preganglionic myelinated –> ACh released by autonomic ganglion –> postganglionic unmyelinated –> ACh released at cholinergic receptors on cardiac smooth muscle
What type of cholinergic receptors are innervated by parasympathetic motor (efferent) neurons?
muscarinic cholinergic receptors
