Autonomic Nervous System and Homeostasis - Chapter 14

Vocabulary flashcards covering the major terms and concepts from Chapter 14 on the Autonomic Nervous System and its role in homeostasis.

Autonomic Nervous System (ANS)

A division of the peripheral nervous system that controls involuntary effectors—cardiac and smooth muscle, and glands—to maintain internal homeostasis.

Visceral Reflex Arc

A neural pathway with sensory and autonomic motor components that regulates unconscious, automatic responses in visceral organs.

Somatic Nervous System

The branch of the nervous system that controls voluntary movements by innervating skeletal muscles.

Sympathetic Nervous System

The fight-or-flight branch of the ANS that mobilizes energy, increases heart rate, dilates bronchioles, and generally prepares the body for stress or activity.

Parasympathetic Nervous System

The rest-and-digest branch of the ANS that conserves energy, slows the heart, stimulates digestion, and promotes routine maintenance functions.

Preganglionic Neuron

The first neuron in an autonomic motor pathway; its cell body lies in the CNS and it synapses in an autonomic ganglion.

Postganglionic Neuron

The second neuron in an autonomic motor pathway; it carries impulses from the ganglion to the target effector.

Adrenal Medulla

An endocrine organ acting as a modified sympathetic ganglion; releases epinephrine and norepinephrine into the bloodstream during sympathetic activation.

Sympathetic Tone

The baseline level of sympathetic activity that continuously maintains partial constriction of blood vessels and influences overall vascular resistance.

Parasympathetic Tone

The ongoing, low-level parasympathetic activity that keeps heart rate low and supports normal digestive and urinary functions at rest.

Homeostasis

The physiological balance of internal conditions (such as temperature, pH, and blood pressure) maintained by coordinated nervous and endocrine regulation.

Autonomic Nervous System (ANS)

A division of the peripheral nervous system that controls involuntary effectors—cardiac and smooth muscle, and glands—to maintain internal homeostasis.

Visceral Reflex Arc

A neural pathway with sensory and autonomic motor components that regulates unconscious, automatic responses in visceral organs.

Somatic Nervous System

The branch of the nervous system that controls voluntary movements by innervating skeletal muscles.

Sympathetic Nervous System

The fight-or-flight branch of the ANS that mobilizes energy, increases heart rate, dilates bronchioles, and generally prepares the body for stress or activity.

Parasympathetic Nervous System

The rest-and-digest branch of the ANS that conserves energy, slows the heart, stimulates digestion, and promotes routine maintenance functions.

Preganglionic Neuron

The first neuron in an autonomic motor pathway; its cell body lies in the CNS and it synapses in an autonomic ganglion.

Postganglionic Neuron

The second neuron in an autonomic motor pathway; it carries impulses from the ganglion to the target effector.

Adrenal Medulla

An endocrine organ acting as a modified sympathetic ganglion; releases epinephrine and norepinephrine into the bloodstream during sympathetic activation.

Sympathetic Tone

The baseline level of sympathetic activity that continuously maintains partial constriction of blood vessels and influences overall vascular resistance.

Parasympathetic Tone

The ongoing, low-level parasympathetic activity that keeps heart rate low and supports normal digestive and urinary functions at rest.

Homeostasis

The physiological balance of internal conditions (such as temperature, pH, and blood pressure) maintained by coordinated nervous and endocrine regulation.

What does the Autonomic Nervous System (ANS) regulate?

Heart rate, blood pressure, digestion, and urinary processes, all under unconscious control.

What are the two main divisions of the motor nervous system?

Somatic and autonomic nervous systems.

What is the primary neurotransmitter released by preganglionic neurons in both sympathetic and parasympathetic divisions?

Acetylcholine (ACh).

What neurotransmitters are released by postganglionic neurons in the Autonomic Nervous System?

In the parasympathetic division, Acetylcholine (ACh); in the sympathetic division, Norepinephrine (NE) or Acetylcholine (ACh) for sweat glands.

Where do sympathetic nerves originate in the spinal cord?

The thoracic and lumbar regions.

Where do parasympathetic nerves originate?

From the brainstem and sacral spinal cord.

What is the sympathetic chain ganglia?

A series of interconnected ganglia located along the vertebral column, part of the sympathetic nervous system.

Explain dual innervation in the context of the ANS.

It is when organs receive regulatory input from both the sympathetic and parasympathetic divisions of the Autonomic Nervous System.

What is the parasympathetic effect on heart rate?

Decreases heart rate.

What is the sympathetic effect on the bronchioles?

Dilates (widens) the bronchioles.

What are the five major special senses?

Smell (olfaction), taste (gustation), vision, hearing (audition), and equilibrium (balance).

List some cranial nerves associated with special senses.

Cranial Nerve I (Olfactory), Cranial Nerve II (Optic), Cranial Nerve VII (Facial), Cranial Nerve IX (Glossopharyngeal), and Cranial Nerve VIII (Vestibulocochlear).

In olfaction, what structures are responsible for detecting odorants?

Olfactory neurons located within the olfactory epithelium.

What type of receptors are olfactory receptors?

Chemoreceptors, which respond to chemical stimuli.

Which cranial nerve transmits signals for the sense of smell?

Cranial Nerve I (CN I), also known as the Olfactory nerve.

What structures are responsible for detecting taste sensations?

Taste buds, primarily located on the papillae of the tongue.

What are the five recognized basic taste sensations?

Sweet, sour, salty, bitter, and umami.

Which cranial nerves primarily carry taste signals to the brain?

Cranial Nerve VII (Facial), Cranial Nerve IX (Glossopharyngeal), and Cranial Nerve X (Vagus).

Name the three main layers of the eye.

The fibrous layer (sclera and cornea), the vascular layer (choroid, ciliary body, and iris), and the neural layer (retina).

What is the primary function of the cornea in the eye?

To refract (bend) light as it enters the eye, directing it towards the retina.

Define accommodation in the context of vision.

The process by which the lens of the eye changes shape to precisely focus light from objects at varying distances onto the retina.

Differentiate between the functions of rods and cones in the retina.

Rods are photoreceptors responsible for vision in dim light and peripheral vision, while cones are responsible for color vision and high-acuity (detailed) vision in bright light.

What specific part of the inner ear is responsible for detecting sound?

The cochlea, containing the spiral organ (Organ of Corti).

What fluid fills the cochlear duct within the inner ear?

Endolymph.

Which cranial nerve transmits auditory (hearing) signals from the inner ear to the brain?

Cranial Nerve VIII (CN VIII), the Vestibulocochlear nerve.

How are hair cells stimulated within the cochlea, leading to sound perception?

Hair cells are stimulated by the movement of the basilar membrane, which vibrates in response to sound waves.

Which structures in the inner ear are responsible for detecting linear acceleration and head tilt?

The utricle and saccule, located in the vestibule.

Which structures in the inner ear detect rotational movements of the head (angular acceleration)?

The semicircular ducts.

What aspects of equilibrium are regulated by the vestibule of the inner ear?

Static equilibrium and the sensing of head position relative to gravity.