Autonomic Nervous System BMF Year 1

The part of the nervous system that controls involuntary bodily functions, maintaining homeostasis.

The ANS has two main parts: sympathetic and parasympathetic, which often have opposing effects.

The division of the ANS that prepares the body for "fight or flight" responses.

The division of the ANS that promotes "rest and digest" functions.

Most internal organs receive input from both sympathetic and parasympathetic systems.

Partial activation of the ANS, with both divisions working in a balanced way.

A muscle or gland innervated by autonomic nerves.

The CNS (brain and spinal cord) controls the output of the ANS, regulating functions.

Increased activity in one branch of the autonomic nervous system often leads to decreased activity in the other.

Both sympathetic and parasympathetic systems are involved in activities such as urination and defecation, but controlled via both systems.

A physiological response triggered in emergency situations, resulting in increased heart rate, and other actions focused on dealing with a threat.

A physiological response that promotes bodily maintenance and restoration, usually in calming situations.

Some degree of constant activity is present in both sympathetic and parasympathetic systems, even if an organ is not faced with an emergency.

The sympathetic nervous system prepares the body for "fight or flight" situations, triggering responses like increased heart rate and dilated pupils.

The parasympathetic nervous system promotes "rest and digest" functions, slowing heart rate, constricting pupils, and aiding in digestion.

Both sympathetic and parasympathetic pathways involve two neurons: a preganglionic neuron from the CNS and a postganglionic neuron from the ganglion to the effector organ.

In the sympathetic nervous system, preganglionic fibers are short and myelinated, while postganglionic fibers are long and unmyelinated.

In the parasympathetic nervous system, preganglionic fibers are long and myelinated, while postganglionic fibers are short and unmyelinated.

The inner part of the adrenal gland, it is considered a modified sympathetic ganglion controlled by the sympathetic nervous system.

Cells in the adrenal medulla release adrenaline (epinephrine) and noradrenaline (norepinephrine) directly into the blood, amplifying sympathetic responses.

Parasympathetic preganglionic neurons originate from the cranial nerves (III, VII, IX, and X) and sacral spinal nerves (S2-S4).

The process by which a nerve terminal releases neurotransmitters into the synaptic cleft.

The binding of a neurotransmitter to its specific receptor on the postsynaptic membrane.

The breakdown or removal of neurotransmitters from the synaptic cleft, ending their activity.

A drug that blocks the action of acetylcholine at muscarinic receptors.

A drug that mimics the action of norepinephrine or epinephrine at adrenergic receptors.

A drug that blocks the action of norepinephrine or epinephrine at adrenergic receptors.

A condition where blood pressure drops significantly when standing up.

A general term for disorders of the Autonomic Nervous System.

The specific effect a neurotransmitter has on a target tissue is determined by the type of receptor present, not the neurotransmitter itself.

Ligand-gated ion channels that directly allow ions to pass through the membrane in response to a neurotransmitter binding.

Receptors that indirectly influence ion channels through a series of steps involving G proteins and second messengers.

A type of cholinergic receptor found on postganglionic ANS cell bodies, activated by acetylcholine and nicotine.

A subtype of acetylcholine receptor, found on effector cells, activated by the mushroom toxin muscarine.

Nicotinic receptors are ionotropic, leading to fast responses. Muscarinic receptors are metabotropic, leading to slower, more complex responses.

Nicotinic receptors are found on postganglionic ANS cell bodies.

Muscarinic receptors are found on effector cell membranes.

Metabotropic receptors activated by acetylcholine (ACh). Responsible for parasympathetic nervous system effects, mediating responses like heart rate reduction and digestive stimulation.

A type of muscarinic receptor that inhibits heart contraction. Found on cardiac tissue, it increases potassium conductance and reduces calcium influx.

A subtype of muscarinic receptor that stimulates digestive processes. Found in the digestive system, it couples to calcium signaling, promoting digestive actions.

Ionotropic receptors activated by acetylcholine (ACh). Found at neuromuscular junctions and in autonomic ganglia, they mediate fast, depolarizing responses.

A site where preganglionic parasympathetic fibers synapse with postganglionic neurons. Nicotinic ACh receptors are present here.

A nerve fiber that carries a signal from a ganglion to an effector organ. In the parasympathetic system, it releases ACh to activate muscarinic receptors.

The target organ or cell that responds to signals from the autonomic nervous system. Parasympathetic stimulation often results in 'rest and digest' functions.

Activation of the parasympathetic nervous system, leading to a 'rest and digest' response. It uses ACh at both synapses, acting on nicotinic and muscarinic receptors.