Nokea
Which feedback loop inhibits the stimulus or the deviation from homeostasis?
- A. Negative feedback loop
- B. Positive feedback loop
- C. Inhibitory feedback loop
- D. Stimulating feedback loop
Correct Answer: A
Rationale: The correct answer is A: Negative feedback loop. Negative feedback loops work to inhibit the stimulus or reduce the deviation from a set point, maintaining homeostasis by counteracting any changes from the norm. In this case, the negative feedback loop acts to minimize any deviation from the body's internal balance, ensuring stability and optimal functioning. Choice B, a positive feedback loop, amplifies the stimulus or deviation, moving systems away from homeostasis. Choice C, an inhibitory feedback loop, is not a commonly recognized term in the context of feedback mechanisms. Choice D, a stimulating feedback loop, is not a standard term and does not accurately describe a feedback loop's role in maintaining homeostasis.
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What happens during expiration?
- A. The diaphragm contracts and the thoracic cavity expands.
- B. The diaphragm relaxes and the thoracic cavity contracts.
- C. The thoracic cavity expands, increasing pressure.
- D. The diaphragm relaxes and moves upward.
Correct Answer: B
Rationale: The correct answer is B. During expiration, the diaphragm relaxes, causing the thoracic cavity to contract. As the thoracic cavity decreases in size, the pressure inside the lungs increases, leading to air flowing out of the lungs. This process helps to expel carbon dioxide-rich air from the body. Choices A, C, and D are incorrect. In choice A, the diaphragm contracting and the thoracic cavity expanding describes inspiration, not expiration. Choice C is incorrect because during expiration, the thoracic cavity actually decreases in size. Choice D is incorrect as the diaphragm moving upward is not a typical movement associated with expiration.
What are the primary processes involved in breathing?
- A. Inspiration and Expiration
- B. Inhalation and Exhalation
- C. Respiration and Circulation
- D. Inspiration and Respiration
Correct Answer: A
Rationale: The primary processes involved in breathing are inspiration (inhaling air) and expiration (exhaling air). Inspiration is the process of taking air into the lungs, while expiration is the process of expelling air from the lungs. These two phases are crucial for gas exchange, where oxygen is taken in during inspiration and carbon dioxide is expelled during expiration. Choices B, C, and D are incorrect as they either combine inspiration with respiration or include unrelated processes like respiration and circulation. Therefore, the correct pair of processes involved in breathing is A, inspiration and expiration.
What is a gene, and what is the relationship between genes, genotype, and phenotype?
- A. A gene is a sequence of amino acids; genes make up proteins; genotype determines phenotype
- B. A gene is a portion of DNA; genes determine traits; genotype is the genetic makeup; phenotype is the physical manifestation
- C. A gene is a protein; proteins determine traits; genotype is the set of all genes
- D. A gene is a lipid; lipids determine traits; phenotype is the physical manifestation
Correct Answer: B
Rationale: A gene is a portion of DNA that contains the instructions for a specific trait. Genotype refers to the genetic makeup of an organism, encompassing all its genes. Phenotype, on the other hand, is the observable physical manifestation resulting from the interaction between an organism's genotype and environmental factors. Choice A is incorrect because genes do not consist of amino acids directly; they are sequences of nucleotides. Choice C is incorrect as genes do not determine traits directly but provide the instructions for proteins that may influence traits. Choice D is incorrect as genes are not lipids, and lipids do not determine traits; they are a type of biomolecule with different functions.
Which types of glial cells are found in the CNS?
- A. Schwann cells, satellite cells
- B. Astrocytes, microglia, ependymal cells, oligodendrocytes
- C. Satellite cells, microglia, oligodendrocytes
- D. Astrocytes, Schwann cells, satellite cells
Correct Answer: B
Rationale: The correct answer is B. Glial cells in the CNS include astrocytes, microglia, ependymal cells, and oligodendrocytes. Schwann cells and satellite cells are found in the PNS. Astrocytes are the most abundant type of glial cells and are involved in nutrient support, repair, and maintenance of the extracellular environment. Microglia are the resident immune cells of the CNS, playing a role in immune defense. Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, contributing to the production and circulation of cerebrospinal fluid. Oligodendrocytes are responsible for producing myelin, which insulates axons in the CNS. Understanding the specific functions of each type of glial cell is essential in grasping the complexity of the central nervous system's support and protective mechanisms.
What are the structural and functional units responsible for creating and transporting urine, located in the cortex of the kidney?
- A. Glomerulus
- B. Nephrons
- C. Loops of Henle
- D. Distal tubules
Correct Answer: B
Rationale: The correct answer is 'Nephrons.' Nephrons are the structural and functional units of the kidneys responsible for creating and transporting urine. Each kidney contains thousands of nephrons located in the cortex and medulla. The nephron consists of the renal corpuscle, which includes the glomerulus, and the renal tubule, which consists of the proximal tubule, loops of Henle, and distal tubule. While the glomerulus, loops of Henle, and distal tubules are all parts of the nephron, the nephrons as a whole are specifically responsible for creating and transporting urine.