Nervous System Basics Quiz

A neuron responsible for controlling voluntary movements of skeletal muscles. It sends signals directly to the muscle fibers, causing them to contract.

A nerve that belongs to the sympathetic nervous system. This system prepares the body for 'fight-or-flight' responses, increasing heart rate, breathing, and alertness.

A type of nerve fiber that originates in the central nervous system and synapses with a postganglionic neuron in a sympathetic ganglion.

A type of nerve fiber that originates in a sympathetic ganglion and innervates target organs like sweat glands, smooth muscle, and blood vessels.

A branch of a spinal nerve that carries preganglionic sympathetic fibers from the spinal cord to a sympathetic ganglion.

A small ganglion located near the eye, receiving parasympathetic fibers from the oculomotor nerve (CN III) and providing them to the ciliary muscle and iris sphincter.

A gland located above the outer corner of the eye responsible for producing tears.

A ganglion located near the submandibular gland, receiving parasympathetic fibers from the facial nerve (CN VII) and providing them to the submandibular and sublingual salivary glands.

A ganglion located near the parotid gland, receiving parasympathetic fibers from the glossopharyngeal nerve (CN IX) and providing them to the parotid salivary gland.

The tenth cranial nerve (CN X), responsible for parasympathetic innervation of many organs, including the heart, lungs, digestive system, and urinary bladder.

The division of the autonomic nervous system responsible for the 'fight-or-flight' response. It increases heart rate, blood pressure, and respiration, while reducing blood flow to the skin and digestive system.

The division of the autonomic nervous system responsible for the 'rest-and-digest' response. It slows heart rate, lowers blood pressure, and promotes digestion and waste elimination.

The normal background activity level of the autonomic nervous system, representing the balance between the sympathetic and parasympathetic divisions, adjusting according to the body's needs.

The continuous, low-level activity of the sympathetic nervous system, maintaining functions like partial vasoconstriction and blood pressure.

The continuous, low-level activity of the parasympathetic nervous system, maintaining functions like smooth muscle tone in the intestines and resting heart rate.

A cluster of nerve cell bodies where a preganglionic neuron from the CNS synapses with a postganglionic neuron in the autonomic nervous system.

The first neuron in the autonomic nervous system, originating in the brainstem or spinal cord and extending to an autonomic ganglion.

The second neuron in the autonomic nervous system, originating in an autonomic ganglion and extending to the target organ.

A single neuron pathway that transmits motor signals from the CNS directly to skeletal muscles.

The two-neuron pathways that transmit motor signals from the CNS to visceral effectors (cardiac muscle, smooth muscle, and glands) in the autonomic nervous system.

The tenth cranial nerve, responsible for parasympathetic innervation of various organs, including the heart, lungs, digestive system, and some glands.

A network of nerves located near the heart, responsible for regulating heart rate and force of contraction.

A network of nerves located near the lungs, responsible for regulating breathing and bronchodilation.

A network of nerves located near the esophagus, responsible for regulating swallowing and peristalsis.

A network of nerves located along the aorta, responsible for innervating various abdominal organs, including the intestines, kidneys, and adrenal glands.

A network of nerves located in the pelvic cavity, responsible for innervating the bladder, rectum, and reproductive organs.

Nerves originating from the sacral spinal cord, responsible for parasympathetic innervation of the pelvic organs.

The nervous system of the digestive tract, operating independently of the central nervous system.

A congenital condition characterized by the absence of enteric nervous system in a segment of the colon, leading to severe constipation.

Massive dilation of the colon due to blockage caused by Hirschsprung disease, resulting in severe constipation and abdominal distension.

The part of the nervous system that controls involuntary functions like heart rate, breathing, and digestion.

The sympathetic nervous system is also known as the thoracolumbar division because its preganglionic neurons originate from the thoracic (T1-T12) and lumbar (L1-L2) regions of the spinal cord.

The sympathetic division has relatively short preganglionic fibers and long postganglionic fibers. This means that the signal from the spinal cord to the ganglion is short, but the signal from the ganglion to the target organ is long.

The cell bodies of preganglionic neurons in the sympathetic nervous system are located in the lateral horns of the spinal cord gray matter.

Sympathetic fibers exit the spinal cord through spinal nerves T1 to L2 and lead to the nearby sympathetic chain ganglia.

The sympathetic chain ganglia are series of interconnected ganglia located along both sides of the vertebral column. They are also called paravertebral ganglia.

There are typically 3 cervical, 11 thoracic, 4 lumbar, 4 sacral, and 1 coccygeal ganglia in the sympathetic chain.

Sympathetic nerve fibers are distributed to every level of the body, providing widespread control over physiological functions.

The white communicating ramus is a myelinated nerve fiber that carries preganglionic sympathetic fibers from the spinal nerve to the sympathetic chain ganglion. It is myelinated, which allows for faster signal transmission.

The gray communicating ramus is an unmyelinated nerve fiber that carries postganglionic sympathetic fibers from the sympathetic chain ganglion back to the spinal nerve. It is unmyelinated, which allows for slower signal transmission.

The neurotransmitter acetylcholine (ACh) is released at the preganglionic synapse, while norepinephrine (NE) is released by postganglionic fibers.

The sympathetic nervous system uses adrenergic receptors (alpha 1, alpha 2, beta 1, and beta 2) on target organs. These receptors are activated by norepinephrine and epinephrine.

Postganglionic fibers leaving the sympathetic chain can take three different routes: 1) synapse directly in the ganglion they enter, 2) travel up or down the chain and synapse in a different ganglion, or 3) pass through the chain without synapsing and continue as splanchnic nerves.

Splanchnic nerves are sympathetic nerves that pass through the sympathetic chain without synapsing and continue to innervate organs in the abdomen.

The sympathetic nervous system is responsible for the "fight-or-flight" response, preparing the body for stressful situations. It increases heart rate, breathing, and blood flow to muscles, while decreasing digestive function.

The autonomic nervous system (ANS) relies on two primary neurotransmitters: acetylcholine (ACh) and norepinephrine (NE). ACh is secreted by preganglionic neurons in both sympathetic and parasympathetic divisions, as well as by postganglionic parasympathetic neurons. NE is secreted by almost all sympathetic postganglionic neurons.

Cholinergic fibers are axons that release acetylcholine (ACh) as their neurotransmitter.

Cholinergic receptors are any receptors that bind to acetylcholine (ACh).

There are two main types of cholinergic receptors: muscarinic and nicotinic. Muscarinic receptors are found on cardiac muscle, smooth muscle, and gland cells, while nicotinic receptors are located on postganglionic neurons of the ANS, adrenal medulla, and neuromuscular junctions of skeletal muscles.

Adrenergic fibers are axons that release norepinephrine (NE) as their neurotransmitter.

Adrenergic receptors are receptors that bind to norepinephrine (NE).

There are two main types of adrenergic receptors: alpha (α) and beta (β). Alpha receptors can be further divided into α1 and α2 subtypes, usually associated with excitatory effects. Beta receptors are subdivided into β1 and β2 subtypes, often linked to inhibitory effects.

The ANS influences glandular secretion indirectly by regulating blood flow to the glands. Vasodilation increases blood flow, leading to increased secretion, while vasoconstriction decreases blood flow, causing a reduction in secretion.

Sympathetic effects tend to persist longer than parasympathetic effects because NE released by sympathetic fibers is reabsorbed by nerves, diffuses to surrounding tissues, and enters the bloodstream. In contrast, ACh released by parasympathetic fibers is rapidly broken down at the synapse.

Dual innervation refers to the situation where most viscera receive nerve fibers from both the sympathetic and parasympathetic divisions of the ANS.

When the sympathetic and parasympathetic divisions of the ANS have opposing effects on the same effector cells, it is referred to as antagonistic effects. For example, the sympathetic division increases heart rate, while the parasympathetic division decreases it.

Cooperative effects occur when the sympathetic and parasympathetic divisions of the ANS work together on different effectors to achieve a unified effect. For instance, both divisions contribute to salivary secretion, with the parasympathetic stimulating serous cell secretion and the sympathetic stimulating mucous cell secretion.

Some organs, such as the adrenal medulla, arrector pili muscles, sweat glands, and many blood vessels, receive only sympathetic fibers. These organs are not under dual innervation.

Sympathetic vasomotor tone refers to a baseline firing frequency of sympathetic fibers that maintains blood vessels in a state of partial constriction. This tone acts as a baseline mechanism for regulating blood flow.