Month: August 2025

Co-transmission occurs when neurons release multiple neurotransmitters to regulate complex physiological responses. Definition of Co-transmission: It is the simultaneous release of more than one neurotransmitter from a single neuron, usually from the same synaptic vesicle or nearby vesicles. Key Features: Neurotransmitters can be classical (e.g., acetylcholine) and peptides (e.g., substance P) or amines (e.g., dopamine). … Read more

Parasympathomimetic Drugs (Cholinergic Agonists) are agents that mimic acetylcholine, stimulating parasympathetic activity to control functions like smooth muscle contraction, gland secretion, and reduced heart rate. Definition of Parasympathomimetic Drugs: Parasympathomimetics are drugs that mimic the action of the parasympathetic nervous system. They enhance the effects of acetylcholine (ACh) at muscarinic or nicotinic Classification with MOA: … Read more

Neurotransmitters are classified as excitatory, inhibitory, or modulatory, based on their role in nerve signaling. Excitatory Neurotransmitters These promote depolarization of the postsynaptic membrane, increasing the likelihood of an action potential. Glutamate: Main excitatory neurotransmitter in the CNS Aspartate: Excitatory amino acid in the CNS Acetylcholine: Excitatory at the neuromuscular junction (nicotinic receptors) Norepinephrine (Noradrenaline): … Read more

Neurohumoral transmission is the process where nerve impulses release chemical messengers to transmit signals. Definition: Neurohumoral transmission refers to the process by which a nerve impulse leads to the release of a chemical substance (neurotransmitter), which then acts on a target cell (neuron, muscle, or gland) to produce a specific physiological response. Steps of Neurohumoral … Read more

The autonomic nervous system regulates vital functions like heart rate, digestion, respiration, and glandular activity. Sympathetic Nervous System (Fight or Flight) Prepares the body for emergency or stressful situations. Physiological effects: Heart: ↑ heart rate and force of contraction (β1) Blood vessels: Vasoconstriction (α1) in skin and viscera; vasodilation (β2) in skeletal muscle Lungs: Bronchodilation … Read more

Organization of the autonomic nervous system (ANS) includes sympathetic and parasympathetic divisions controlling involuntary functions. What is the Autonomic Nervous System (ANS)? The Autonomic Nervous System (ANS) is a part of the Peripheral Nervous System (PNS) that controls involuntary body functions—those that happen without conscious thought. It regulates: Heart rate, Breathing rate, Digestion, Pupillary response, … Read more

Peripheral Nervous System (PNS) is the part of the nervous system outside the brain and spinal cord, consisting of cranial nerves, spinal nerves, and peripheral ganglia. It connects the central nervous system (CNS) to limbs and organs, enabling sensory input and motor responses. The PNS includes all nerves outside the brain and spinal cord. It … Read more