Autonomic Nervous System - Section 13

What are examples of vegetative functions?

- Temperature - Digestion - heart rate - Respiration - Metabolism - maintenance of internal organs homeostasis - blood pressure - Influences muscle tone

The sympathetic response occurs during situations of stress and involves the following

- accelerated heart rate - increase blood pressure - shift of blood flow from the skin and gastrointestinal (GI) tracked to the skeletal muscles and brain - Suppression of immune response - Sleep disturbances - More pain and longer to heal - Mental health depression and anxiety - increase blood flow - dilation of the bronchioles and pupils - constriction of the stomach, intestines, and internal sphincter of the urethra

The ANS does the following:

- innervates the internal organs, blood vessels, and glands - regulates cardiac and smooth muscle (muscle of glands and organs) - regulates secretion from glands - controls vegetative functions (functions that allow the body to continue functioning despite its severe brain damage)

symptoms of Horner's syndrome are ipsilateral and include the following

- ipsilateral miosis (constriction of the pupil) - Partial ptosis ( drooping of the ipsilateral I) - Flushed dry skin on the ipsilateral face - Cannot sweat - ipsilateral sunken eyeball

Signs and symptoms vary depending on which structures of the ANS are involved but may include the following:

- orthostatic hypotension (low blood pressure due to changing the position) - urinary and bowel incontinence - gastrointestinal disorders - inability to regulate temp decreased pupillary response

What is autonomic neuropathy?

Autonomic neuropathy is an ANS disorder that affects involuntary body functions such as heart rate, blood pressure and sweating.

The spinal cord contains important ANS reflexes that are modulated by higher ______ centers

CNS

What can autonomic neuropathy be related to?

Causes can be related to a large number of diseases affecting ANS including autoimmune diseases, nerve injury, diabetes and some infectious diseases.

Chronic fatigue syndrome and fibromyalgia have been linked to what?

Chronic fatigue syndrome and fibromyalgia have been linked to decreased stage 4 sleep

Disorders of the RAS can result in what?

Disorders of the RAS can result and disrupted sleep wake cycles and attentional problems (severe and ability to focus and concentrate, impulsivity)

T/F The parasympathetic nervous system activates the flight/fight response

False - the sympathetic nervous system

When there is lost communication between spinal cord reflexes and higher CNS centers, as in spinal cord injury, search reflexes function in an unmodified manner

For example, uncontrolled sweating, vasomotor instability and reflux bowel and bladder functions occur with regulation of ANS spinal cord level reflexes are lost

The limbic lobe has a role in the relationship between our emotions and the ANS

Heightened emotional states can cause the sympathetic nervous system to become activated and dampen are sympathetic nervous system activity

Significant lesions RAS can result in stuporous states of consciousness (near uncosuness). When the RAS is lost, the reticular inhibitory system may become dominant and produce heightened somnolence. What does this mean?

It means the RIS will take over, making someone extremely tired.

What happens if there is an injury to the brain stem?

Severe injury to the brain stem often results in death or poor prognosis

What is the autonomic nervous system?

The autonomic nervous system (ANS) is a subdivision of the peripheral nervous system that independently regulates critical life body functions without the need for cortical input.

The central portion of the ANS consists of parts of the ...

The central portion of the ANS consists of parts of the cerebral cortex, hypothalamus, thalamus, limbic system, cerebellum and spinal cord.

The reticular formation sends and receives projections to and from where?

The diencephalon, cortex and spinal cord.

It filters all incoming sensory information and alerts the cortex to attend to import in sensory input

This results in a sharpening of action to important sensory information from the environment

The reticular formation also receives sensory fibers from the somatic and visceral systems (including vision and olfaction).

This sensory information is then relayed to the thalamus and cortex for CNS regulation.

T/F Autonomic nerve damage disrupts messages sent between the brain and ANS

True

T/F the brain stem (aka reticular formation) influences muscle tone

True

T/F When individuals are in great pain, nausea may occur as a result of the connections between the ANS, the vagus nerve and the limbic lobe.

True Similarly, blushing, heart palpitations, clammy hands, and dry mouth are emotional responses that are mediated by limbic structures and the ANS.

T/F The reticular inhibitory system (RIS) is involved in producing calming states and sleep.

True - Certain types of sensory input, such as slow rocking or deep pressure, can activate RIS to calm the body.

T/F If the brainstem remains intact but the cortex is no longer active, patients can still survive

True - but they are considered to be in a persistent vegetative state (because the brainstem controls vegetative functions).

When humans are agitated or nervous, they may experience loss of appetite because the sympathetic nervous system is geared up and has shut down the digestive system (regulated by the parasympathetic nervous system)

When humans and animals are frightened, loss of bladder control can occur; Fear Can interfere with ANS regulation.

Lesions to the RIS can result in constant wakefulness and vigilance. What does this mean?

When the RIS is damaged, the RAS may become dominant and cause heightened arousal. (can't fall asleep)

The reticular formation consists of interconnected neurons that are diffusely located throughout the midbrain, pons and medulla.

aka the brain stem

The reticular activating system (RAS) is the portion of the reticular formation that is responsible for what?

arousal, alertness and wakefulness.

- These ganglionic fibers are located in the periphery - Their cell bodies are located in the _______ ganglia within the ANS organs (groups organ and tissues)

automatic

Preganglionic fibers have their cell bodies in the _______ _________ (cranial nerves 3, 7, 9, 10, 11) and _______ ________ ( in the inter medial lateral horn thoracic sections and first two lumbar section)

brain stem spinal cord

The parasympathetic nervous systems preganglionic fibers emerge from the ___________ and sacral spinal cord

brainstem sacral spinal cord

Continued overactivation of the sympathetic nervous system has been linked to what?

cardiovascular disease, immune suppression, depression, anxiety, inflammatory responses, sleep disturbances and pain.

The parasympathetic NS is responsible for what?

cellular repair tissue restoration parasympathetic nervous system activity promote homeostasis and facilitates cellular repair and tissue restoration

Stress promote sympathetic nervous system activity and ___________ cellular repair

decreased

Studies have shown that individuals with chronic stress are more prone to what?

disease, illness and physical and mental health disorders.

The parasympathetic nervous system is responsible for what?

energy conservation, storage and replenishment

The sympathetic nervous systems preganglionic neurons have their cell bodies located where?

in the intermediate lateral horn of the thoracic and first two lumbar sections of the spinal cord

Chronic activation of the sympathetic nervous system can cause blood vessel constriction, ____________ heart rate, heightened _____________ and _____________ .

increased cholesterol hypetension

The RAS is diffusely located throughout the brainstem but is believed to be primarily located in the __________ , with connections to the thalamus and hypothalamus.

midbrain

The ANS influences _______ _________ through the vestibulospinal, rubrospinal, reticulospinal tract

muscle tone

Stress activates the sympathetic nervous system, causing increased release of what?

norepinephrine, epinephrine (adrenaline) and corticosteroids (stress hormones).

Horner syndrome is an ANS disorder that results from a transection of the

ocular sympathetic pathway (CN 3)

the anterior hypothalamus projects pathways ______________ nervous system

parasympathetic

This brain center is an evolutionarily old part of the nervous system and is involved in the control of what?

posture, visceral motor function, sleep and arousal / wakefulness.

The peripheral components of the ANS consists of ____ and _________ ganglionic fibers that innervate the viscera.

pre and post ganglionic fibers

The reticular formations motor fibers synapse with (a) motor neurons of the ___________ and _________ systems and (b) motor neurons that synapse with ______________ autonomic motor neurons

pyramidal and extrapyramidal preganglionic

The hypothalamus is a major control center of the ANS which controls what?

regulates temperature, thirst, feeding behaviors and endocrine functions (secretion of glands)

The reticulospinal tracts (descending extrapyramidal tracts of the spinal cord that inhibit and facilitate anti-gravity muscles and thereby influence muscle tone) originate in the ____________ ___________

reticular formation.

The parasympathetic NS is heightened during restorative or

stage 4 sleep

the posterior hypothalamus produce pathways to the __________ nervous system

sympathetic

There are respiratory and cardiovascular centers in the reticular formation that control vital functions and reflexes such as

the gag, cough, sneeze, swallow and vomit reflexes

The hypothalamus exerts autonomic regulation over various brain stem centers that control __________ functions (i.e. life-sustaining functions such as cardiovascular and respiratory functions).

vegetative