Chapter 16: Autonomic Nervous System

Identify the divisions of the Autonomic Nervous System (ANS)

- Enteric Nervous System - Sympathetic - Parasympathetic

Which are parasympathetic effects on the reproductive system?

- Penile or clitoral engorgement - Stimulation of glandular secretion in the male reproductive tract

Name the locations of the nicotinic receptors

- Postganglionic neurons in the autonomic ganglia - Skeletal muscle cells

Which are sympathetic effects on the urinary system?

- Reduced urine output by the kidneys - Contraction of the internal urethral sphincter

Which are parasympathetic effects on the urinary system?

- Relaxation of the internal urethral sphincter - Contraction of the urinary bladder wall

The peripheral nervous system (PNS) is composed of what types of neurons?

- Sensory neurons - Motor neurons

Which are sympathetic effects on the reproductive system?

- Smooth muscle role in orgasm - Labor contractions of the uterus

Identify the nerves that transmit sympathetic information

- Spinal nerves T1 - T12 - Spinal nerves L1 - L2

Which are associated with the parasympathetic division of the autonomic nervous system?

- Urination - Digestion - Defecation

Describe a nerve plexus

A complex, interconnected neural network formed by neurons of the sympathetic and parasympathetic divisions

What is a preganglionic neuron?

A neuron that extends from the spinal cord or brainstem to a ganglion

Which nervous system division is usually under involuntary control?

Autonomic

What is the effect of parasympathetic stimulation on the heart?

Decreases heart rate

Name the effector site for the enteric nervous system (ENS)

Digestive tract

Identify the location of muscarinic receptors

Effector cells of postganglionic neurons

True or false: All neurotransmitters result in excitatory stimulation when they bind to target receptors

False: Depending on the cell type, the response is excitatory or inhibitory.

True or False: Parasympathetic nerve signals will pass via the spinal nerves to reach the neck.

False: Parasympathetic nerve signals to the neck travel with cranial nerves, not spinal nerves.

True or false: It is physiologically impossible for a target tissue to be stimulated by both the sympathetic and parasympathetic nervous systems

False: Tissues do respond differently to simulation from these systems. However, the results are not always opposite

What is the effect of parasympathetic stimulation of muscarinic receptors in the stomach?

Increases muscle contraction

Name the peripheral nervous system component responsible for the transmission of action potentials from the CNS to the periphery

Motor neurons

Which part of the nervous system carries information to and from the CNS and various regions of the body?

Peripheral nervous system

Name the division of the ANS containing preganglionic neurons synapses with many postganglionic neurons and which typically has greater stimulatory effects

Sympathetic

What convention is used to name autonomic nerve plexuses?

They are named for the associated organs.

Describe a postganglionic neuron.

They are unmyelinated and extend from the autonomic ganglion to the target cells

Agonists bind to specific receptors and _____ them, whereas antagonists bind to specific receptors and _____ them.

activate, inactivate

Drugs that bind to specific receptors and activate them are called ______, whereas drugs that prevent activation are called ______

agonists, antagonists

The combined effects of the parasympathetic and sympathetic divisions on a target

are not always opposite in their effects

Homeostasis is maintained primarily by the

autonomic nervous system

Autonomic nerve plexuses found supplying the heart would be called

cardiac plexuses

Name the location of the receptors for acetylcholine and norepinephrine

cell membrane

If a sympathetic nerve secretes acetylcholine, the neuron is called a(n) _____ neuron

cholinergic

The division of the autonomic nervous system that is only associated with the walls of the digestive tract is the

enteric nervous system

Adrenal medulla cells are divided into two groups, those that secrete ___________ and those that secrete __________

epinephrine, norepinephrine

The sympathetic division shunts blood and nutrients to structures that are active and away from non-essential organs. This is sometimes called the ______

fight-or-flight response

The adrenal medulla is the ______ portion of the adrenal gland

inner

The primary function of the ANS is to ______

maintain homeostasis

Action potentials are carried from the central nervous system (CNS) to the periphery by ______ neurons, while ______ neurons carry action potentials from the periphery to the CNS

motor, sensory

Effector cells that respond to acetycholine released from postganglionic neurons possess ______ receptors on their cell membranes.

muscarinic

Cholinergic receptors located in the membrane of all postganglionic neurons in the autonomic ganglia and in the membranes of skeletal muscle cells are

nicotinic

A sudden increase in blood pressure initiates a ______ reflex that ______ the cardiac muscle cells

parasympathetic, inhibits

The rate of smooth muscle contraction in the digestive organs is increased when the neurotransmitters of the ______ division of the autonomic nervous system bind to _____ receptors.

parasympathetic, muscarinic

Parasympathetic nerve signals will pass via the ______ to reach the large intestine

pelvic splanchnic nerves

A complex, interconnected neural network formed by neurons of the sympathetic and parasympathetic division is called a nerve

plexus

Receptors for acetylcholine and norepinephrine receptors are located in the

postsynaptic membrane

The autonomic nervous system uses _____ to help maintain homeostasis in the absence of CNS input

reflexes

The pelvic splanchnic nerves are formed by preganglionic parasympathetic fibers from the ______ region of the spinal cord

sacral

For the somatic motor nervous system, _________ motor neurons carry impulses from the CNS to effectors (skeletal muscles). In the autonomic nervous system, _____________ (number) autonomic neurons carry signals from central nervous system to the effectors

somatic, two

Depending on the body location, the parasympathetic division of autonomic nervous system is

stimulatory or inhibitory

A sudden decrease in blood pressure initiates a _____ reflex that ______ the heart.

sympathetic/excites

How many neurons form the autonomic nervous system pathways?

two