Limbic System and Higher Order Functions

what is another name for the autonomic nervous system?

Visceral motor system.

which brain regions regulate autonomic processes below the conscious level?

Hypothalamus and brainstem.

What does the autonomic nervous system transmit signals to?

Heart, smooth muscle, and glands.

What kind of inputs does the autonomic nervous system respond to?

Visceral sensory inputs, such as from blood vessels.

What is the primary function of the autonomic nervous system?

To maintain homeostasis.

Viscera (internal organs) =

core

structures in skin (sweat glands, blood vessels) =

periphery

sympathetic function is

flight or fight

parasympathetic function is

rest and digest

How many lower autonomic motor neurons does the ANS use to reach an effector?

A chain of two lower autonomic motor neurons.

Where is the cell body of the preganglionic neuron located?

Within the brainstem or spinal cord.

Where does the preganglionic neuron project its axon?

To an autonomic ganglion in the peripheral nervous system.

What neurotransmitter does the preganglionic neuron release?

Acetylcholine (ACh).

Where is the cell body of the postganglionic neuron located?

Within an autonomic ganglion.

Where does the postganglionic neuron project its axon?

To cardiac muscle, smooth muscle, or glands.

What neurotransmitters does the postganglionic neuron release?

Acetylcholine (ACh) or norepinephrine (NE).

What effect do neurotransmitters from the postganglionic neuron have on effectors?

They either excite or inhibit the effector, depending on the receptor types.

What are cells that release acetylcholine called?

Cholinergic neurons.

What are cells that release norepinephrine called?

Adrenergic neurons.

What are the advantages of the two-neuron chain in the ANS

It allows for neuronal convergence — multiple preganglionic neurons synapse on one postganglionic neuron.

It allows for neuronal divergence — one preganglionic neuron’s axon branches to synapse with numerous postganglionic neurons.

How does neuronal convergence and divergence benefit the ANS function?

It helps coordinate muscle and visceral responses efficiently.

What is another name for the parasympathetic division of the ANS?

Craniosacral division.

Where are the preganglionic neurons of the parasympathetic division located?

In the brainstem or S2–S4 spinal cord segments.

How do the lengths of preganglionic and postganglionic axons compare in the parasympathetic division?

Preganglionic axons are long; postganglionic axons are short.

Where are parasympathetic ganglia located?

Close to or within the effector organ.

What are the names of the ganglia in the parasympathetic division?

Terminal ganglia and intramural ganglia.

Which cranial nerve’s parasympathetic component arises from the Edinger-Westphal nucleus?

Cranial Nerve III (Oculomotor nerve).

What parasympathetic functions are controlled by CN III?

Intrinsic eye muscles — sphincter pupillae and ciliary muscle.

Which glands are innervated by the parasympathetic fibers of CN VII?

Submandibular, sublingual, and lacrimal glands.

Which gland is innervated by the parasympathetic fibers of CN IX?

Parotid gland.

What does CN X parasympathetically innervate?

Visceral organs (thoracic and abdominal viscera).

Where do the sacral components of the parasympathetic division originate?

Lateral gray horns of spinal cord segments S2–S4.

What organs do the sacral parasympathetic fibers innervate?

Distal end of the gastrointestinal tract and pelvic organs.

What is another name for the sympathetic division of the ANS?

Thoracolumbar division.

Where are the preganglionic neurons of the sympathetic division located?

In the lateral horns of spinal cord segments T1–L2.

How do the lengths of preganglionic and postganglionic axons compare in the sympathetic division?

Preganglionic axons are short; postganglionic axons are long.

Where are sympathetic ganglia located relative to the spinal cord?

Close to the spinal cord, lateral or anterior to it.

What are some targets of the superior cervical ganglion?

Sweat glands, blood vessels, and the dilator pupillae muscle of the eye.

What is dual innervation in the autonomic nervous system?

When an organ receives input from both the sympathetic and parasympathetic divisions.

What types of effects can dual innervation have on an organ?

Antagonistic or cooperative effects.

What is an example of antagonistic effects between the two ANS divisions?

Control of heart rate — parasympathetic activity slows it, sympathetic activity increases it.

What is an example of cooperative effects in dual innervation?

Sexual response, where parasympathetic and sympathetic stimulations have different effects that combine in an overall response.

pupil dilation in the eye is what response

SNS

pupil constriction in the eye is what response

PNS

decrease lacrinmal gland secretions is what response

SNS

increase lacrinmal gland secretions is what response

PNS

increase heart rate and contractile force is what response

SNS

decrease heart rate and contractile force is what response

PNS

bronchial dilation and decrease secretion in the lungs is what response

SNS

bronchial constriction and increase secretion in the lungs is what response

PNS

decrease peristalsis, decrease secretion in the gastrointestinal, and vasculature constriction is what response

SNS

increase peristalsis, increase secretion in the gastrointestinal, and vasculature dilation is what response

PNS

bladder filling is what response

SNS

bladder emptying is what response

PNS

erection of penis or clitoris is what response

PNS

ejaculation is what response

SNS

Output from the ANS is heavily influenced by the

hypothalamus

What are some key physiological processes regulated by the hypothalamus?

Blood pressure, body temperature, feeding, metabolic rate.

What feeding-related behaviors can the hypothalamus regulate?

Hyperphagia (excessive eating) and anorexia (reduced eating).

How does the hypothalamus regulate metabolic rate?

By regulating the thyroid gland.

What emotional and behavioral processes does the hypothalamus influence?

Emotional and affective processes, sexual behavior, drinking behavior, defensive behavior.

With which major systems does the hypothalamus have connections?

The autonomic nervous system (ANS) and the limbic system.

How does the hypothalamus contribute to the stress response?

By stimulating the secretion of adrenal stress hormones.

What hormone does the hypothalamus release to initiate the HPA axis response to stress?

Corticotropin-Releasing Hormone (CRH).

What gland does CRH act on and what hormone does that gland release?

CRH acts on the anterior pituitary gland, which releases Adrenocorticotropic Hormone (ACTH).

After ACTH is released into the bloodstream, which organ does it target?

The adrenal cortex.

What hormone does the adrenal cortex release in response to ACTH

Cortisol.

What are the main functions of cortisol in the stress response?

Increasing blood sugar, suppressing the immune system, and aiding metabolism.

How is the HPA axis regulated to prevent excessive cortisol release?

Cortisol provides negative feedback to the hypothalamus and pituitary to reduce CRH and ACTH secretion.

What happens to the HPA axis during chronic stress?

It can become dysregulated, leading to prolonged high cortisol levels.

What are some health problems associated with chronic HPA axis activation?

Immune suppression, metabolic disorders (e.g., diabetes), cardiovascular problems, and mood disorders like anxiety and depression.

How does chronic stress affect the immune system?

Prolonged cortisol exposure suppresses immune function, increasing susceptibility to infections.

What impact does chronic stress have on metabolism?

It can cause insulin resistance, weight gain, and other metabolic disturbances.

How can chronic stress influence mental health?

It increases the risk of anxiety, depression, and cognitive impairments.

Which gland releases norepinephrine and epinephrine during the acute stress response?

The adrenal medulla.

What hormones are released by the adrenal medulla in response to acute stress?

Norepinephrine and epinephrine (adrenaline).

What are some physiological effects of norepinephrine and epinephrine during acute stress?

Increased heart rate, increased blood pressure, increased respiratory rate, and increased blood flow to muscles.

How fast does the release of norepinephrine and epinephrine occur during acute stress?

very quickly, within seconds to minutes.

How does the timing of the HPA axis response compare to the sympathetic response during stress?

The HPA axis response occurs later, over minutes to hours, to sustain and regulate energy.

what are the two main roles of the limbic system

formation of memories

modulation of hypothalamus and brainstem autonomic nervous system functions

How does the limbic system interact with the hypothalamus and cerebral cortex?

It helps create emotions and determine the expression of emotions.

What is the primary role of the hippocampus?

Learning and memory.

What functions is the amygdala involved in?

Emotion and drives.

What is the septal nuclei associated with?

Reward mechanisms

What is the fornix and its main role?

the most prominent output pathway from the hippocampus, projecting to the hypothalamus.

What is special about the dentate gyrus in the brain?

It is one of the only areas (along with the olfactory bulb) where neurogenesis (new neuron formation) occurs

What type of memory loss is associated with Korsakoff’s syndrome?

Anterograde memory loss — inability to form new memories.

What are two common causes of Korsakoff’s syndrome?

Chronic alcoholism and vitamin B (thiamine) deficiency.

Which brain structure is important for encoding procedural (motor learning) memories?

the cerebellum.

What is the process of converting short-term memory into more stable long-term memory called?

Memory consolidation.

Which brain structure is critical for creating declarative memories?

hippocampus

what are the 2 types of long-term working memories

declarative and nondeclarative

what are the types of memories in declarative

episodic (events) and semantic (facts)

Remembering your first day of school or a recent vacation

episodic memory

Knowing that Paris is the capital of France.

semantic

what kind of memory involves the hippocampus and associated cortical areas

declarative

what kind of memory involves the cerebellum, basal ganglia, amygdala

nondeclarative

what are the nondeclarative memories

skills, habits, emotional memory, and conditioned reflexes

knowing how to tie you shoelaces is an examples of

procedural memory

anything with words or numbers; knowing a phone number is an example of

working memory