dandruff is caused by

ATI TEAS 7

TEAS 7 science practice

1. What causes dandruff?

A. Excessive sebum production (This can contribute to oily dandruff)
B. Bacterial infection (This can cause scalp folliculitis, not dandruff)
C. Overgrowth of a specific type of fungus on the scalp
D. Lack of proper skin hydration

Correct answer: C

Rationale: Dandruff is primarily caused by an overgrowth of a specific type of fungus called Malassezia on the scalp. This fungus feeds on the natural oils produced by the hair follicles, leading to irritation and flaking of the scalp skin. Choice A is incorrect because excessive sebum production can contribute to oily dandruff, but it is not the primary cause of dandruff. Choice B is incorrect as bacterial infection primarily causes scalp folliculitis, not dandruff. Choice D is incorrect as dandruff is not primarily caused by a lack of proper skin hydration.

2. Which plane divides the body into superior (top) and inferior (bottom) halves?

A. Sagittal/Median Plane
B. Frontal/Coronal Plane
C. Transverse/Cross-Section Plane
D. Horizontal Plane

Correct answer: C

Rationale: The Transverse or Cross-Section Plane is the correct answer as it divides the body into superior (top) and inferior (bottom) halves. This plane runs horizontally across the body, perpendicular to the long axis, separating the body into upper and lower sections. Choice A, the Sagittal/Median Plane, divides the body into left and right halves, not superior and inferior halves. Choice B, the Frontal/Coronal Plane, divides the body into anterior (front) and posterior (back) halves. Choice D, the Horizontal Plane, is not a standard anatomical plane used to divide the body into specific sections.

3. The innate immune system provides a non-specific first line of defense. What are some physical barriers that contribute to the innate immune system?

A. Antibodies
B. Phagocytes
C. Skin and mucous membranes
D. Memory B cells

Correct answer: C

Rationale: Physical barriers such as the skin and mucous membranes are crucial components of the innate immune system's first line of defense. These barriers act as physical obstacles that prevent pathogens from entering the body. Antibodies (option A) are produced by the adaptive immune system in response to specific pathogens and do not serve as physical barriers. Phagocytes (option B) are cells that engulf and digest pathogens, playing a role in the innate immune response but not as physical barriers. Memory B cells (option D) are part of the adaptive immune system and aid in mounting a faster and more effective immune response upon subsequent exposure to a specific pathogen, but they are not physical barriers against initial pathogen entry.

4. What does the concept of punctuated equilibrium suggest?

A. Evolution occurs gradually through the continuous accumulation of small changes over long periods.
B. Evolution is characterized by long periods of relative stasis punctuated by rapid bursts of evolutionary change.
C. The fossil record is a complete and accurate representation of all past life forms.
D. Natural selection primarily favors extreme phenotypes within a population.

Correct answer: B

Rationale: Punctuated equilibrium suggests that evolution is characterized by long periods of relative stasis punctuated by rapid bursts of evolutionary change. This concept, proposed by Stephen Jay Gould and Niles Eldredge, implies that species remain relatively unchanged for extended periods, followed by sudden bursts of rapid evolution. Option A describes the gradualism model, which is different from punctuated equilibrium. Option C is inaccurate as the fossil record is incomplete and biased. Option D is unrelated to the concept of punctuated equilibrium.

5. Using anatomical terms, what is the relationship of the sternum to the deltoid?

A. Medial
B. Lateral
C. Superficial
D. Posterior

Correct answer: A

Rationale: The sternum is located at the midline of the body, closer to the center, making it medial to the deltoid. The deltoid muscle is positioned on the lateral side of the upper arm, away from the midline. Therefore, the correct relationship of the sternum to the deltoid is medial. 'Lateral' is incorrect as it refers to a position farther away from the midline, 'Superficial' is incorrect as it relates to a structure being closer to the surface, and 'Posterior' is incorrect as it indicates a position behind or toward the back.