Physiology With Every Option Explained

Explanation

(Option C) Protection against pathogens: The trachea is lined with a layer of mucus and cilia, which act as a defense mechanism against pathogens, such as bacteria and viruses, which may enter the respiratory system. The mucus traps foreign particles and microorganisms, while the cilia beat in coordinated motions to move the mucus upwards towards the throat, where it can be expelled through coughing or swallowing. This mechanism helps to prevent pathogens from reaching the lungs and causing infections.

(Option A) Gas exchange: Gas exchange primarily occurs in the alveoli of the lungs, not in the trachea. While the trachea serves as a pathway for air to travel to and from the lungs, the actual exchange of oxygen and carbon dioxide occurs in the alveoli.

(Option B) Humidification of air: Humidification of air occurs primarily in the upper respiratory tract, particularly in the nasal cavity and the paranasal sinuses. The trachea does not play a significant role in this process.

(Option D) Vocalization: While the trachea is involved in vocalization, its primary function is not vocalization itself but rather providing a passage for air to pass through the larynx, where sound is produced. The vibration of the vocal cords in the larynx produces sound, and the trachea then carries the sound waves to the outside environment.

(Option E) Filtration of air: Filtration of air primarily occurs in the upper respiratory tract, particularly in the nasal cavity, where tiny hairs called cilia and mucus trap particles and pathogens. The trachea does not have a significant role in the filtration of air.

Subject: Physiology

System/ Title: Respiratory (Transport of Gases)

Topic: Airway Structure and Function

Explanation

(Option D) Glutamate: Glutamate is an excitatory neurotransmitter that plays a key role in the transmission of signals in the nervous system, including pain signals. It is the primary neurotransmitter involved in the process of nociception, which is the sensing of harmful stimuli and the transmission of pain signals.

(Option A) Serotonin: Serotonin is a neurotransmitter that plays a role in mood regulation, sleep, and appetite. It is not directly associated with the transmission of pain signals in the nervous system.

(Option B) GABA (Gamma-aminobutyric acid): GABA is an inhibitory neurotransmitter that has a calming effect on the nervous system. It is not directly involved in the transmission of pain signals.

(Option C) Dopamine: Dopamine is a neurotransmitter associated with reward and pleasure. While it plays a role in various brain functions, it is not primarily involved in the transmission of pain signals.

(Option E) Acetylcholine: Acetylcholine is a neurotransmitter that is involved in muscle contraction, as well as functions related to memory and learning. While it has diverse functions, it is not the primary neurotransmitter associated with the transmission of pain signals.

Subject: Physiology

System/ Title: Nervous System (Receptors – Transmission of Pain)

Topic: Neurotransmitters and Pain Transmission

Explanation

(Option B) Regulation of blood sugar: The pancreas has both endocrine and exocrine functions. In the context of the endocrine system, the pancreas plays a crucial role in regulating blood sugar levels. It does so by secreting hormones, primarily insulin and glucagon, into the bloodstream. Insulin is responsible for lowering blood sugar levels by facilitating the uptake of glucose into cells, where it can be used for energy or stored. On the other hand, glucagon raises blood sugar levels by promoting the release of glucose from the liver into the bloodstream.

(Option A) Digestion: The pancreas also has an exocrine function related to digestion. It secretes digestive enzymes into the small intestine to help break down carbohydrates, proteins, and fats in the food we eat.

(Option C) Filtration of blood: Filtration of blood is not a primary function of the pancreas. The kidneys are the main organs responsible for blood filtration, as they filter waste and excess substances to form urine.

(Option D) Production of bile: Bile is produced by the liver, not the pancreas. However, the pancreas does release its pancreatic juices into the small intestine, which contains enzymes that aid in the digestion of fats.

(Option E) Storage of nutrients: The storage of nutrients is primarily handled by other organs like the liver and adipose (fat) tissues. While the pancreas is involved in regulating nutrient levels in the bloodstream, it is not a major organ for nutrient storage.

Subject: Physiology

System/ Title: Endocrine System (Pancreas) – Endocrine Glands

Topic: Pancreas and Regulation of Blood Sugar

Explanation

(Option D) Purkinje fibers: Purkinje fibers are specialized cardiac muscle fibers that rapidly conduct the electrical impulses through the ventricles, causing coordinated and synchronized contraction of the ventricles. They play a crucial role in the rapid spread of the cardiac impulse, ensuring efficient and synchronized ventricular contractions.

(Option A) Atrioventricular Node (AV Node): The AV node is responsible for delaying the electrical impulse that travels from the atria to the ventricles. It acts as a gatekeeper, allowing a brief delay to ensure proper coordination of atrial and ventricular contractions. It does not contribute to the rapid spread of the cardiac impulse through the ventricles.

(Option B) Bundle of His: The bundle of His is a continuation of the AV node and is responsible for transmitting the electrical impulses from the atrioventricular node to the ventricles. It helps in the rapid conduction of the impulse, but it is not primarily responsible for the rapid spread through the ventricles.

(Option C) Sinoatrial Node (SA Node): The SA node is often referred to as the natural pacemaker of the heart. It generates electrical impulses that initiate the heartbeat and cause the atria to contract. However, it is not involved in the rapid spread of the cardiac impulse through the ventricles.

(Option E) Bundle Branches: The bundle branches are part of the electrical conduction system of the heart and help transmit the impulses to specific regions of the ventricles. However, the rapid spread of the cardiac impulse through the ventricles is primarily facilitated by the Purkinje fibers.

Subject: Physiology

System/ Title: CVS (Conducting Tissues of Heart)

Topic: Purkinje Fibers and Ventricular Conduction in the Heart

Explanation

(Option B). Interphase: Interphase is the longest phase of the cell cycle. It's the period between cell divisions when the cell is actively growing, performing its normal functions, and preparing for division. Interphase is further divided into three subphases: G1 (cell growth and preparation), S (synthesis of DNA), and G2 (further growth and preparation for division).

(Option A) M Phase: The M (Mitosis) Phase is the phase of the cell cycle when the actual cell division takes place, including both mitosis (nuclear division) and cytokinesis (division of the cytoplasm). It is a relatively short phase compared to interphase.

(Option C) Leptotene: Leptotene is a specific subphase of prophase during mitosis. It's a very early stage when chromosomes start to condense and become visible under a microscope. This phase is not the longest in the cell cycle.

(Option D) S Phase: The S (Synthesis) Phase is part of interphase. It's the phase during which DNA replication occurs. New DNA strands are synthesized based on the existing template strands. While important, the S Phase is just one part of the overall interphase and is not the longest phase of the cell cycle.

(Option E) Telophase: Telophase is the final stage of mitosis when the separated chromosomes reach opposite poles of the cell. It is not the longest phase but marks the completion of nuclear division.

Subject: Physiology

System/ Title: General (Cell)

Topic: Cell Cycle