Nokea
What type of joint is found at the elbow?
- A. Ball and socket
- B. Hinge
- C. Pivot
- D. Saddle
Correct Answer: B
Rationale: The correct answer is B: Hinge. A hinge joint, such as the one found at the elbow, allows for movement primarily in one plane, enabling flexion and extension similar to the movement of a door hinge. This joint structure permits bending and straightening of the arm, controlling the range of motion in a specific direction. Choices A, C, and D are incorrect. A ball and socket joint allows for multi-axial movement like the hip joint, a pivot joint allows for rotation around an axis like the joint between the first and second cervical vertebrae, and a saddle joint allows for movement in two planes at right angles to each other like the joint at the base of the thumb.
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What is the main function of white blood cells?
- A. To carry oxygen
- B. To fight infections
- C. To carry nutrients
- D. To remove waste products
Correct Answer: B
Rationale: The main function of white blood cells, also known as leukocytes, is to fight infections and foreign invaders to protect the body from harm. They play a crucial role in the immune system by identifying and destroying pathogens like bacteria and viruses, essential for maintaining the body's health and overall immunity. Choices A, C, and D are incorrect as carrying oxygen is primarily done by red blood cells, carrying nutrients is a function of various body systems, and removing waste products is mainly the role of the kidneys and liver, not white blood cells.
What is the role of platelets in the blood?
- A. To transport oxygen
- B. To fight infections
- C. To clot blood
- D. To carry nutrients
Correct Answer: C
Rationale: Platelets, also known as thrombocytes, play a crucial role in blood clotting. When there is an injury, platelets adhere to the site and release substances that form a clot, preventing excessive bleeding. This function is vital for maintaining hemostasis and preventing blood loss. Choice A is incorrect because red blood cells, not platelets, are responsible for transporting oxygen. Choice B is incorrect as white blood cells are primarily responsible for fighting infections. Choice D is incorrect as nutrients are mainly transported by plasma and red blood cells, not platelets.
What is the primary function of platelets in the blood?
- A. To carry oxygen
- B. To fight infections
- C. To clot blood
- D. To transport nutrients
Correct Answer: C
Rationale: The correct answer is C: To clot blood. Platelets, also known as thrombocytes, have a primary function in blood clotting. They help in the process of coagulation, forming clots to prevent excessive bleeding when injuries occur. Platelets play a crucial role in maintaining the integrity of the circulatory system by sealing off damaged blood vessels and promoting wound healing. Choices A, B, and D are incorrect because platelets do not carry oxygen, fight infections, or transport nutrients in the blood.
What is the role of enzymes in the body?
- A. To produce energy
- B. To speed up chemical reactions
- C. To transport molecules
- D. To repair tissues
Correct Answer: B
Rationale: Enzymes are biological catalysts that facilitate and speed up chemical reactions in the body. They do not produce energy but enable various processes such as digestion and metabolism by lowering the activation energy required for reactions to occur. Choice A is incorrect because enzymes do not produce energy themselves but assist in energy production through reactions. Choice C is incorrect as enzymes do not primarily function in transporting molecules, although some may have a role in specific transport processes. Choice D is incorrect as the primary role of enzymes is not to repair tissues, but rather to catalyze biochemical reactions.
When an individual is under stress, hormones are released. Which of the following is not one of the locations where hormones are released when under stress?
- A. Parathyroid gland
- B. Adrenal cortex
- C. Posterior pituitary
- D. Hypothalamus
Correct Answer: A
Rationale: The parathyroid gland is not a location where hormones are typically released during stress. It primarily regulates calcium levels in the blood through the release of parathyroid hormone (PTH). On the other hand, the adrenal cortex releases hormones like cortisol in response to stress, the posterior pituitary releases oxytocin and antidiuretic hormone, and the hypothalamus plays a crucial role in coordinating stress responses through the release of corticotropin-releasing hormone (CRH). Therefore, the parathyroid gland is the correct answer as it is not directly involved in the stress response pathway.