Which anatomical structure houses the malleus, incus, and stapes?

 

This is a process in which compact and spongy bone develops directly from sheets of mesenchymal (undifferentiated) connective tissue.

Choice A is wrong because vertebrae are formed by endochondral ossification, which is a process in which bone develops from a pre-existing cartilage model.

Choice B is wrong because long bones of arms and legs are also formed by endochondral ossification.

Choice C is wrong because bones of the pelvic girdle are also formed by endochondral ossification.

Lysosomes are organelles that contain enzymes that can break down foreign particles and bacteria.

Phagocytes are a type of white blood cell that use phagocytosis to engulf bacteria, foreign particles, and dying cells to protect the body. They bind to pathogens and internalise them in a phagosome, which acidifies and fuses with lysosomes in order to destroy the contents.

Choice B is wrong because Golgi apparatus is an organelle that modifies, sorts, and packages proteins and other molecules for transport within or outside the cell.

It does not contribute to phagocytosis.

Choice C is wrong because vacuoles are organelles that store water, nutrients, waste products, or other substances.

They do not contribute to phagocytosis.

Choice D is wrong because endoplasmic reticulum is an organelle that synthesizes proteins and lipids, and transports them within the cell.

It does not contribute to phagocytosis.

When the sympathetic nervous system is stimulated, it prepares the body for a fight-or-flight response by increasing the heart rate and blood pressure, which results in increased cardiac output.

Cardiac output is the amount of blood pumped by the heart per minute.

Choice B is wrong because increased pancreatic activity is not a result of sympathetic stimulation. The sympathetic nervous system inhibits digestion and reduces blood flow to the gastrointestinal tract.

Choice C is wrong because increased uterine activity is not a result of sympathetic stimulation. The sympathetic nervous system relaxes the smooth muscles of the uterus and other reproductive organs.

Choice D is wrong because increased gastrointestinal activity is not a result of sympathetic stimulation. The sympathetic nervous system inhibits digestion and reduces blood flow to the gastrointestinal tract.

The correct answer is choice B. Ear wax.

Ceruminous glands are specialized sweat glands that are located in the external auditory canal.

They secrete a waxy substance called cerumen or ear wax by mixing their secretion with sebum and dead epidermal cells. Cerumen helps to protect the ear from physical damage and infection.

Choice A is wrong because sebum is secreted by sebaceous glands, not ceruminous glands. Sebum is an oily substance that lubricates and protects the hair and skin.

Choice C is wrong because mucus is secreted by mucous glands, not ceruminous glands. Mucus is a slippery substance that moistens and protects the inner lining of various organs.

Choice D is wrong because keratin is not a secretion, but a protein that forms the structure of hair, nails and skin.