Chapter 4 - The Peripheral Nervous System: Sensory, Auntonomic, Somatic

Question 0

Sensory afferent

Answer 0

• pathway coming into the central nervous system that carries information that reaches the level of consciousness

Question 1

Visceral afferent

Answer 1

• a pathway coming into the central nervous system that carries subconscious information derived from the internal viscera

Question 2

Autonomic nervous system

Answer 2

• the portion of the efferent division of the PNS that innervates smooth and cardiac muscles, and exocrine glands; composed of two subdivisions: the sympathetic nervous system and the parasympathetic system

Question 3

Somatic nervous system

Answer 3

• the portion of the efferent division of the peripheral nervous system that innervates skeletal muscles; consists of the axonal fibres of the alpha motor neurons

Question 4

Preganglionic fibre

Answer 4

• the first neuron in the two neuron autonomic nerve pathway; originates in the central nervous system and terminates on an autonomic ganglion

Question 5

Postganglionic neuron

Answer 5

• the second neuron in the toe neuron autonomic nerve pathway; originates in an autonomic ganglion and terminates on an effector organ

Question 6

Parasympathetic nervous system

Answer 6

• the subdivision of the autonomic nervous system that dominates in quiet, relaxed situations and promotes body maintenance activities such as digestion and emptying of the bladder

Question 7

Sympathetic nervous system

Answer 7

• the subdivision of the autonomic nervous system that dominates in an emergency or stressful situations and prepares the body for strenuous physical activity

Question 8

Sympathetic ganglion chain

Answer 8

• a chain of ganglion situated ventral and lateral to the spinal cord, and extends from the upper neck down to the coccyx

Question 9

Collateral ganglia

Answer 9

• end point for preganglionic sympathetic autonomic fibres that don’t synapse in the sympathetic chain ganglia - located about halfway between the CNS and the effector organ

Question 10

Terminal ganglia

Answer 10

• Lie in or near the effector organs - end point for preganglionic fibres of the parasympathetic system

Question 11

Acetylcholine

Answer 11

• the neurotransmitter released from all autonomic preganglionic fibres and from all parasympathetic postganglionic fibres

Question 12

Cholinergic fibres

Answer 12

• nerve fibres that release acetylcholine as their neurotransmitter

Question 13

Adrenergic fibres

Answer 13

• nerve fibres that release norepinephrine as their neurotransmitter

Question 14

Varicosities

Answer 14

• sweepings on the terminal branches of autonomic fibres that simultaneously release neurotransmitter over a large area of the organ rather the on single cells

Question 15

Tonic activity

Answer 15

• some neurons are typically constantly active, as opposed to physically active - slowly adapting or tonic receptors respond to steady rate of firing - most often respond to increased activity by increasing their firing frequency

Question 16

Fight or flight

Answer 16

• the changes in activity of the various organs innervates by the autonomic nervous system in response to sympathetic stimulation - collectively prepare the body for strenuous activity in the face of an emergency or stressful situation, such as a physical threat from the outside environment

Question 17

Rest and digest

Answer 17

• promoted by he parasympathetic system - activates certain types of bodily functions while slowing down those activities that are enhanced by the sympathetic system - there is no need, for example, to have the heart beating rapidly and forcefully when the person is in a tranquil setting

Question 18

Adrenal medulla

Answer 18

• the inner portion of the adrenal gland - an endocrine gland that is modified sympathetic ganglion that secretes hormones epinephrine and norepinephrine into the blood in response to sympathetic stimulation

Question 19

Epinephrine

Answer 19

• the primary hormone secreted by the adrenal medulla - important in preparing he body for flight or fight responses and in regulating arterial blood pressure - adrenaline

Question 20

Nicotinic receptors

Answer 20

• type of Cholinergic found at all autonomic ganglia and the motor end plate of skeletal muscles

Question 21

Muscarinic receptors

Answer 21

• type of Cholinergic receptor found at the effector organs of all parasympathetic postganglionic fibres

Question 22

Agonists

Answer 22

• bind to the same receptor as the neurotransmitter and elicit an effect that mimics that of the transmitter

Question 23

Antagonist

Answer 23

• binds with the receptor and block the neurotransmitter’s response

Question 24

Motor neurons

Answer 24

• the neurons that Innervate skeletal muscle and whose axons constitute the somatic nervous system

Question 25

Final common pathway

Answer 25

• The only way any other parts of the nervous system can influence skeletal muscle activity is by acting on motor neurons

Question 26

Neuromuscular junction

Answer 26

• the juncture between a motor neuron and a skeletal muscle fibre

Question 27

Terminal button

Answer 27

• a motor neurons enlarged knob-like ending that terminates near a skeletal muscle fibre and releases acetylcholine in response to an action potential in the neuron

Question 28

Motor end plate

Answer 28

• the specialized portion of a skeletal muscle fibre that lies immediately underneath the terminal button of the motor neuron and possesses receptor sites for finding acetylcholine released from the terminal button

Question 29

End plate potential

Answer 29

• the graded receptor potential that occurs at the motor end plate of a skeletal muscle fibres in response to binding with acetylcholine

Question 30

Acetylcholinesterase

Answer 30

• an enzyme present in the motor end plate membrane of a skeletal muscle fibre that inactivated acetylcholine