Nervous System Organization

The autonomic nervous system controls involuntary bodily functions like heart rate, digestion, and breathing without conscious control.

Maintains a stable internal environment for the body, despite external changes.

The 'fight or flight' response prepares the body for stressful situations by increasing heart rate, dilating pupils, and diverting blood to muscles.

The 'rest and digest' response promotes calm and relaxation by decreasing heart rate, constricting pupils, and directing blood to the digestive system.

A collection of nerves embedded in the lining of the digestive tract controlling its activity.

The first neuron in a two-neuron chain that relays signals from the central nervous system to the target organs.

The second neuron in a two-neuron chain that relays signals from the central nervous system to the target organs.

A neurotransmitter released by most postganglionic sympathetic neurons, responsible for stimulating the 'fight or flight' response.

Nerves in the gut wall that control digestion independently of the brain.

The two major nerve networks within the ENS, located in the muscle layer and submucosa.

Specialized nerve cells in the ENS that detect stretching in the gut wall.

Specialized nerve cells in the ENS that monitor the chemical composition of the gut contents.

Nerves within the ENS that control muscle movement in the gut, promoting peristaltic waves.

Nerves within the ENS that stimulate the release of mucus into the gut lumen.

Nerves within the ENS that connect sensory and motor neurons, facilitating communication.

The main sensory hub in the brainstem that receives visceral sensory information from organs.

Specialized neurons in the intermediolateral horn (IML) of the spinal cord that send axons to synapse with postganglionic neurons in the sympathetic chain or prevertebral ganglia.

A chain of ganglia located along the vertebral column that receives preganglionic axons from the spinal cord.

Nerves that carry preganglionic sympathetic axons from the spinal cord to prevertebral ganglia located in the abdomen.

A network of neurons located in the submucosa layer of the gut that regulates secretion and blood flow.

A network of neurons located between the layers of smooth muscle in the gut that controls gut movements.

A type of acetylcholine receptor that is found in the sympathetic nervous system and is responsible for transmitting signals from preganglionic to postganglionic neurons.

A type of acetylcholine receptor that is found in the parasympathetic nervous system and is responsible for transmitting signals from postganglionic neurons to target organs.

A type of adrenergic receptor that is found in the sympathetic nervous system and is responsible for mediating the effects of adrenaline and noradrenaline.

The myenteric plexus, located between the muscle layers of the gut, is responsible for detecting stretch in the smooth muscles. This helps regulate gut motility and peristalsis.

The submucosal plexus, found in the submucosa layer of the gut, monitors the chemical composition of the lumen. This helps regulate secretion and absorption.

Excitatory and inhibitory visceromotor neurons work together to control peristalsis. Excitatory neurons stimulate muscle contractions, while inhibitory neurons relax the muscles, allowing food to move down the gut.

Secretomotor neurons stimulate the release of mucus into the lumen. Mucus is essential for lubricating food and protecting the gut lining.

Interneurons connect sensory and motor neurons in the ENS. They act like relay stations, transmitting signals between different parts of the network.

The ENS functions largely independently of the brain, but it receives input from the parasympathetic and sympathetic nervous systems. This allows for coordinated control of digestion.

Sensory feedback from the target organs plays a crucial role in regulating autonomic nervous system activity. This allows for fine-tuning of responses based on the physiological state of the organs.

Visceral sensory neurons innervate the target tissues of the ANS, transmitting information about organ function to the central nervous system. This is essential for coordinating appropriate responses and maintaining homeostasis.

The sympathetic chain ganglia, found along the spinal cord, receive lightly myelinated axons from preganglionic neurons, which travel through the ventral root and white ramus communicans.

Prevertebral ganglia receive preganglionic axons via splanchnic nerves, bypassing the chain ganglia. These ganglia are associated with controlling organs in the abdomen and pelvis.

The axons from preganglionic neurons in the sympathetic nervous system that travel through the white ramus communicans and enter the sympathetic chain ganglia. These axons are lightly myelinated.

The axons from postganglionic neurons in the sympathetic nervous system that leave the sympathetic chain ganglia and travel via the gray ramus communicans to innervate target organs.

Sensory neurons carrying information from internal organs to the central nervous system, traveling through the dorsal root ganglion.