Anonymous
Jan 4
Types of neurotransmitter:- mechanism of transmission through synapse and neuromuscular junction, thermoregulation:- exothermic and endothermic regulation, osmoregulation in fishes and amphibians?
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Jan 4
Types of neurotransmitters:
1. Acetylcholine: It is involved in the transmission of nerve impulses in the central nervous system and the neuromuscular junction.
2. Dopamine: It plays a role in reward-motivated behavior and motor control.
3. Serotonin: It regulates mood, appetite, and sleep.
4. Gamma-aminobutyric acid (GABA): It is an inhibitory neurotransmitter that reduces neuronal excitability.
5. Glutamate: It is an excitatory neurotransmitter that enhances neuronal activity.
6. Norepinephrine: It is involved in the "fight or flight" response and regulates attention and arousal.
Mechanism of transmission through synapse:
When an action potential reaches the presynaptic terminal, it triggers the release of neurotransmitters into the synaptic cleft. These neurotransmitters bind to specific receptors on the postsynaptic membrane, causing ion channels to open or close. This leads to a change in the postsynaptic membrane potential, either depolarizing or hyperpolarizing it. If the change is significant enough, it can generate a new action potential in the postsynaptic neuron, continuing the transmission of the signal.
Mechanism of transmission through neuromuscular junction:
The neuromuscular junction is a specialized synapse between a motor neuron and a muscle fiber. When an action potential reaches the presynaptic terminal, it triggers the release of acetylcholine into the synaptic cleft. Acetylcholine binds to receptors on the muscle fiber, causing depolarization of the muscle membrane. This depolarization leads to the release of calcium ions from the sarcoplasmic reticulum, initiating muscle contraction.
Thermoregulation:
Exothermic regulation: Exothermic organisms, such as reptiles and insects, rely on external sources of heat to regulate their body temperature. They bask in the sun or seek shade to adjust their body temperature accordingly.
Endothermic regulation: Endothermic organisms, including mammals and birds, generate heat internally to maintain a constant body temperature. They have a high metabolic rate and can regulate their body temperature even in changing environmental conditions.
Osmoregulation in fishes and amphibians:
Fishes: Most fishes are osmoregulators, meaning they actively regulate the salt concentration in their bodies. They have specialized structures like gills and kidneys to remove excess salts and maintain water balance. Freshwater fishes excrete large amounts of dilute urine, while marine fishes excrete concentrated urine and actively transport salts out through their gills.
Amphibians: Amphibians have permeable skin that allows for both water and salt exchange. They are capable of osmoregulation in both freshwater and terrestrial environments. In freshwater, they actively take in water through their skin and excrete dilute urine. On land, they conserve water by producing concentrated urine and reabsorbing water from their bladder.
1. Acetylcholine: It is involved in the transmission of nerve impulses in the central nervous system and the neuromuscular junction.
2. Dopamine: It plays a role in reward-motivated behavior and motor control.
3. Serotonin: It regulates mood, appetite, and sleep.
4. Gamma-aminobutyric acid (GABA): It is an inhibitory neurotransmitter that reduces neuronal excitability.
5. Glutamate: It is an excitatory neurotransmitter that enhances neuronal activity.
6. Norepinephrine: It is involved in the "fight or flight" response and regulates attention and arousal.
Mechanism of transmission through synapse:
When an action potential reaches the presynaptic terminal, it triggers the release of neurotransmitters into the synaptic cleft. These neurotransmitters bind to specific receptors on the postsynaptic membrane, causing ion channels to open or close. This leads to a change in the postsynaptic membrane potential, either depolarizing or hyperpolarizing it. If the change is significant enough, it can generate a new action potential in the postsynaptic neuron, continuing the transmission of the signal.
Mechanism of transmission through neuromuscular junction:
The neuromuscular junction is a specialized synapse between a motor neuron and a muscle fiber. When an action potential reaches the presynaptic terminal, it triggers the release of acetylcholine into the synaptic cleft. Acetylcholine binds to receptors on the muscle fiber, causing depolarization of the muscle membrane. This depolarization leads to the release of calcium ions from the sarcoplasmic reticulum, initiating muscle contraction.
Thermoregulation:
Exothermic regulation: Exothermic organisms, such as reptiles and insects, rely on external sources of heat to regulate their body temperature. They bask in the sun or seek shade to adjust their body temperature accordingly.
Endothermic regulation: Endothermic organisms, including mammals and birds, generate heat internally to maintain a constant body temperature. They have a high metabolic rate and can regulate their body temperature even in changing environmental conditions.
Osmoregulation in fishes and amphibians:
Fishes: Most fishes are osmoregulators, meaning they actively regulate the salt concentration in their bodies. They have specialized structures like gills and kidneys to remove excess salts and maintain water balance. Freshwater fishes excrete large amounts of dilute urine, while marine fishes excrete concentrated urine and actively transport salts out through their gills.
Amphibians: Amphibians have permeable skin that allows for both water and salt exchange. They are capable of osmoregulation in both freshwater and terrestrial environments. In freshwater, they actively take in water through their skin and excrete dilute urine. On land, they conserve water by producing concentrated urine and reabsorbing water from their bladder.
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