chapter 14 Flashcards
(23 cards)
controls visceral functions
ANS
dominates during times of stress, exertion, and/or emergencies
Sympathetic Division
dominates during resting conditions
Parasympathetic divison
network of neurons in the walls of the digestive tract that can work independently of the CNS
Enteric Division
Axons emerge from the thoracic and upper lumbar regions
Innervate ganglia close to the spinal cord
Sympathetic NS
Axons emerge from the brain stem and sacral region
Innervate ganglia close to or in target organs
Parasympathetic NS
100 million neurons (same number as in the spinal cord) + all neurotransmitters found in the brain
Controls visceral reflexes without CNS assistance
Enteric Nervous System
Prepares body for heightened somatic activity Increases: Mental awareness Metabolic rate Respiration rate/dilation of passageways Heart rate/blood pressure Sweat glands Energy reserves Decreases: Digestion and urinary functions
Sympathetic NS
Regulates visceral function and energy conservation Increases: Salivary secretions Blood flow to the digestive system Urination and defecation functions Decreases: Metabolic rate Heart rate/blood pressure
Parasympathetic NS
Primarily interactions between norepinephrine (NE) and epinephrine (E) and alpha and beta receptors in the plasma membrane
Stimulation of Sympathetic NS
Primarily interactions between acetylcholine (ACh) and nicotinic and muscarinic receptors
Stimulation of the Parasympathetic NS
whole system response to crisis
Sympathetic NS:
Sympathetic activation
system stimulation that leads to increased nutrient content in the blood
Parasympathetic NS:
Anabolic System
provides concise control over visceral functions through innervation of major organs and the Para- and Sympathetic NS
ANS control
continuous level of spontaneous activity in the absence of stimuli
Autonomic tone
organs that receive instructions from the Para- and Sympathetic NS
Dual innervation
provide autonomic motor responses
Can be modified, facilitated, and/or inhibited by higher centers (like the hypothalamus)
Polysynaptic
Reflex arc consists of a receptor, a sensory neuron, a processing center (interneurons), and one or two visceral motor neurons
2 types:
Short reflexes
Long reflexes
Visceral reflexes
Bypass the CNS
Sensory neurons + interneurons
Control very simple motor functions (e.g. enteric nervous system)
Short reflex
Deliver information to the CNS through the dorsal roots of the spinal nerves, sensory branches of cranial nerves, and autonomic nerves of visceral effectors
Coordinate responses from multiple organ systems
Long reflexes
collect visceral sensory information from tissues and organs
Include nociceptors, thermoreceptors, tactile receptors, baroreceptors, and chemoreceptors
Solitary nuclei – brain stem
Interoceptors
monitor change in pressure (stretch receptors)
Help regulate cardiac functions, blood flow to vital tissues, and lung expansion
Baroreceptors
monitor concentration changes of specific chemicals or compounds
Found in the medulla oblongata and other parts of the brain, carotid bodies, and aortic bodies
Regulate respiration and cardiovascular functions
Chemoreceptors
activity is controlled by centers in the brain stem
Simple reflexes controlled at the autonomic ganglia and spinal cord level
Complex reflexes controlled by the medulla oblongata (which is controlled by the hypothalamus)
Because of the interconnectedness of the brain, multiple responses can occur from a single ‘emotion’ or reaction
ANS levels of control
