Physiology Ch.7

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The sympathetic nervous system is part of the __________ nervous system.

autonomic

Cardiac muscle, smooth muscle, most exocrine glands, some endocrine glands, and adipose tissue are innervated by the ____.

autonomic nervous system

What chemical agent causes an explosive release of ACh?

black widow spider venom

Most visceral organs are innervated by _______________ nerve fibers.

both parasympathetic and sympathetic

Propagation of an action potential to the axon terminal triggers the opening of what kind of voltage-gated channels?

calcium

agonist

causes same response as neurotransmitter

__________ blocks the action of acetylcholine at the acetylcholine receptor on the motor end-plate.

curare

The __________ contains acetylcholinesterase, acetylcholine receptors and cation channel proteins.

motor end-plate

The specialized portion of the muscle cell membrane immediately under the terminal button is known as the_________.

motor end-plate

ALS (Lou Gehrig's disease) is characterized by degeneration and eventual death of____________ .

motor neurons

Skeletal muscle cells are innervated by _______________.

motor neurons

A single muscle cell is called a(n) _________.

muscle fiber

One disease known as ____________is characterized by extreme muscular weakness.

myasthenia

As the axon approaches a muscle, it divides into many terminal branches and loses its myelin sheath. Each of these axon terminals forms a special junction called _______ ____________.

neuromuscular junction

As the axon approaches a muscle, it divides into many terminal branches and loses its myelin sheath. Each of these axon terminals forms a special junction called _____________.

neuromuscular junction

The ________ is the junction between a motor neuron and a skeletal muscle fiber.

neuromuscular junction

cotransmitters

secreted along with neurotransmitter

In the ___________ nervous system, there is a single neuron from the origin in the CNS to the effector organ.

somatic

Stimulation of the _________ division of the autonomic nervous system causes an increased heart rate.

sympathetic

The __________ nervous system promotes responses that prepare the body for strenuous physical activity.

sympathetic

Smooth muscle cells are innervated by ___________.

sympathetic nerve fibers

The axon terminal is enlarged into a knoblike structure called a(n) _______.

terminal button

What kind of receptor responds to acetylcholine released by all autonomic preganglionic fibers?

​nicotinic cholinergic receptors

What neurotransmitter is released from the parasympathetic postganglionic fiber?

​norepinephrine

Acetylcholinesterase is located ____.

​on the motor end-plate membrane

What do chemoreceptors monitor?

​protein or fat content of ingested food

What is the most harmful result of prolonged depolarization at cholinergic sites?

​respiratory failure

What kind of muscles are respiratory muscles?

​skeletal

How is most of the motor activity in the somatic nervous system coordinated?

​subconsciously

Each autonomic nerve pathway (from the CNS to an innervated organ) consists of how many nerves?

​two

Where are the cell bodies of almost all motor neurons situated within the spinal cord?

​ventral horn

What are some examples of autonomic cotransmitters?

ATP, dopamine, and neuropeptide Y

Efferent neurons carry instructions from the CNS to the effector organs.

True

Most visceral (internal) organs are innervated by both sympathetic and parasympathetic nerve fibers.

True

Motor neurons innervate skeletal muscle and trigger voluntary movement.

True

Organophosphates (example: sarin gas) irreversibly block acetylcholinesterase (AChE), resulting in respiratory failure.

True

The neurotransmitter released at the neuromuscular junction is acetylcholine (ACh).

True

________ released from the motor neuron diffuses across the cleft and binds with specific receptor sites.

Acetylcholine

What response is triggered when the sympathetic system is dominant?

​fight or flight response

What is the shape of a muscle cell or fiber?

​long and cylindrical

What are the two types of cholinergic receptors?

​nicotinic and muscarinic

Afferent neurons terminate at interneurons.

True

What cranial nerve directly impacts heart rate by decreasing it?

. ​X (vagus)

__________ exerts its lethal blow by blocking the release of ACh from the terminal button in response to an action potential in the motor neuron.

Botulinum toxin

A neuromuscular junction is a link between two motor neurons.

False

Acetylcholinesterase (AChE) is an enzyme that keeps the muscle cell's electrical response turned on.

False

Adrenergic fibers release acetylcholine.

False

Botulinum toxin acts by triggering explosive release of ACh from storage vesicles at all cholinergic sites.

False

Preganglionic fibers release neurotransmitter onto effector organs in the autonomic nervous system pathway.

False

The autonomic nervous system is subject to voluntary control.

False

The somatic nervous system can both stimulate and inhibit effector organs.

False

The somatic nervous system originates in the lateral horn of the thoracic spinal cord.

False

_____________ receptors are found on the cell membrane of cardiac muscle, smooth muscle and glands.

Muscarinic

_______________ receptors respond to acetylcholine released from both sympathetic and parasympathetic preganglionic fibers.

Nicotinic

____________ postganglionic fibers are short, terminating on the effector organs.

Parasympathetic

dominance is concerned with general "housekeeping" activities.

Parasympathetic

__________ dominance promotes the "fight or flight" response.

Sympathetic

__________nerve fibers originate in the thoracic and lumbar regions of the spinal cord.

Sympathetic

Where do the sympathetic nerve fibers originate?

The lateral horn of the thoracic and lumbar regions of the spinal cord

Acetylcholine can bind to nicotinic receptors in the autonomic nervous system.

True

The chemical neurotransmitter at the neuromuscular junction is__________.

acetylcholine

The venom of black widow spiders exerts its deadly effect by causing an explosive release of ___________ from the storage vesicles.

acetylcholine

___________ is an enzyme in the motor end plate membrane that inactivates acetylcholine.

acetylcholinesterase

A(n) _________ binds with the receptor and causes the same response as the neurotransmitter would.

agonist

A(n) ________ binds with the receptor and prevents the neurotransmitter from causing a response.

antagonist

The parasympathetic and sympathetic nerve fibers innervate most visceral organs, a phenomenon called __________ .

dual innervation

motor neuron

efferent somatic fiber

Acetylcholinesterase is classified as a(n) ____.

enzyme

Acetylcholinesterase

inactivates acetylcholine

Each muscle cell connects to how many neuromuscular junctions?

one

__________ are a group of chemicals that modify neuromuscular junction activity.

organophosphates

The __________ division of the autonomic nervous system stimulates contraction of the bladder wall.

parasympathetic

The ____________ nervous system dominates in quiet, relaxed situations.

parasympathetic

________ system promotes "rest and digest" bodily functions.

parasympathetic

norepinephrine, epinephrine fight or flight acetylcholine muscarinic receptor rest and digest

parasympathetic sympathetic both parasympathetic parasympathetic

antagonist

prevents neurotransmitter from acting

What response is triggered when the parasympathetic system is dominant?

rest and digest response

autonomic

two-neuron chain

The somatic system is considered to be under ___________ control.

voluntary

What type of control exists in the somatic nervous system?

voluntary

Botulinum toxin exerts its lethal blow by blocking the release of what chemical compound?

​ACh

What chemical compound do motor-neuron axon terminals release?

​acetylcholine

What neurotransmitter is released from the sympathetic preganglionic fiber?

​acetylcholine

What is a compound called that mimics a neurotransmitter's response?

​agonist

Curare blocks the action of ACh at receptor-channels. Therefore, it is considered a(n) ____.

​antagonist

The poliovirus selectively destroys what part of the somatic nervous system?

​cell bodies of motor neurons

Parasympathetic preganglionic fibers arise from the ____.

​cranial and sacral areas of the CNS

Innervation of a single organ by both branches of the autonomic nervous system is known as ____.

​dual innervation


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