Physiology chapter 11

describe the physiological roles of the effernet (motor) nervous system

it transmits signals form the central nervous system (CNS) to the muscles and glands, enabling the body to respond to various stimuli, it has two parts somatic motor division and autonomic division

Somatic motor division

controls skeletal muscles and is often associated with voluntary movements.

autonomic division

regulates involuntary functions by controlling smooth and cardiac muscles, as well as glands, its further divided into sympathetic and parasympathetic 

sympathetic branch

part of the autonomic division, often associated with the fight or flight response, prepping the body for action 

parasympathetic branch

part of the autonomic division, promotes rest and digest activities, conserving energy and maintaining homeostasis. 

describe the structure and function of the adrenal medulla

specialized neuroendocrine tissue located at the core of the adrenal gland which sits atop the kidneys, its part of the sympathetic nervous system and is responsible for secreting catecholamines primarily epinephrine

describe the mechanism occurring at the neuromuscular junction 

critical site where a motor neuron communicates with a muscle fiber to initiate muscle contraction. 

action potential travels down the motor neuron to the axon terminal

voltage gates Ca channels open, allowing calcium ion to enter the axon terminal

influx of calcium triggers the release of ACh from synaptic vesicles into the synaptic cleft

ACh diffuses and binds to nicotinic acetylcholine receptors on the motor end plate of muscle fiber

this binding causes ion channels to open, leading to depolarization and the generation of muscle action potential

Acetylcholinesterase in the synaptic cleft breaks down the ACh terminating the signal. 

neuromuscular junction

where a motor neuron communicates with a muscle fiber to initiate contraction

cholinergic neuron

nicotinic or muscarinic receptor

adrenergic neuron

adrenergic receptor

What is the graded potential that occurs at the motor end plate of skeletal muscle?

end-plate potential

Test anxiety can produce the following symptoms: the need for frequent urination, dilated pupils, and a dry mouth. What branch of the autonomic nervous system would cause these symptoms?

sympathetic

Binding of acetylcholine to ________ receptors causes ________ by opening channels that primarily permit sodium to permeate the membrane.

nicotinic : depolarization

Parasympathetic neurons from which cranial nerve innervate most of the viscera in the thoracic and abdominal cavities?

X vagus

At rest, what is the relative contribution of the sympathetic and parasympathetic nervous systems to the regulation of homeostasis?

Both systems are active but the parasympathetic predominates

The neurotransmitters norepinephrine and epinephrine can also function as neurohormones when secreted by which structure?

adrenal medulla

Which neurotransmitter is released by sympathetic preganglionic axons at their synapses with ganglionic neurons?

ACh

Which of the following is one general function of the parasympathetic division of the ANS?

increased smooth muscle activity along the digestive tract

Which cholinergic receptors are found on the surfaces of all ganglionic neurons of both the parasympathetic and sympathetic divisions of the ANS

nicotinic

Under most conditions, which neurons secrete acetylcholine

preganglionic sympathetic neurons

somatic motor neurons

preganglionic parasympathetic neurons

postganglionic parasympathetic neurons