MCAT Biology : Epithelial Tissue and Integumentary System

Study concepts, example questions & explanations for MCAT Biology

varsity tutors app store varsity tutors android store

Example Questions

← Previous 1

Example Question #1 : Connective Tissue And Epithelium

Which of the following is not a function of simple squamous epithelium?

Possible Answers:

Diffusion

Filtration

Absorption

Osmosis

Correct answer:

Absorption

Explanation:

Simple squamous epithelium is a single layer of flat cells that is found in areas where passive transfer takes place. This includes the blood vessels (capillaries), the alveoli, and the glomerulus. The capillaries and alveoli are specialized for diffusion and osmosis, while the glomerulus is specialized for filtration.

Absorption is typically associated with simple columnar epithelium (found in the small intestine) and simple cuboidal epithelium (found in the nephrons).

Example Question #2 : Connective Tissue And Epithelium

Which area of the body would not be expected to have stratified squamous epithelium?

Possible Answers:

Skin

Esophagus

Tongue

Small intestine

Correct answer:

Small intestine

Explanation:

Stratified squamous epithelium is primarily associated with protection of the body, and is found in areas that commonly encounter stress. These areas include the skin, the tongue, and the esophagus. The small intestine is associated with absorption, and is lined with simple columnar epithelium.

Example Question #3 : Connective Tissue And Epithelium

The ability to regulate body temperature within a particular range of values, even in varying environmental conditions, is known as __________.

Possible Answers:

thermodynamics

adaptation

thermoregulation

temperature sensitivity

thermal feedback

Correct answer:

thermoregulation

Explanation:

Thermoregulation is a homeostatic mechanism for regulating body temperature in varying conditions. This is accomplished by physiological, structural, and behavioral mechanisms. For example, many mammals will shiver as a result of small muscle contractions to generate heat. Many of the other possible answers sound similar, but are incorrect. Thermoregulation is a type of environmental adaptation, but "adaptation" is too broad of an answer in this case.

Example Question #4 : Connective Tissue And Epithelium

Which of the following mechanisms is involved in temperature regulation?

Possible Answers:

Sweating

Constriction of blood vessels

Dilation of blood vessels

Shivering

All of these answers

Correct answer:

All of these answers

Explanation:

All of these mechanisms are used to either increase or decrease body temperature, allowing for proper temperature regulation. When your body becomes cold, shivering (the result of involuntary muscle contractions) helps increase body temperature. Constriction of blood vessels diverts warm blood to the most critical organs and away from extremities. In hot temperatures, blood vessels dilate to allow more blood to the surface of the skin where heat exchange can occur. Sweating allows excess heat to be released through the evaporation of water. Without all of these mechanisms, humans would have difficulty surviving in all the environments we currently inhabit around the world.

Example Question #1 : Epithelial Tissue And Integumentary System

In order to maintain homeostasis of body temperature, humans must utilize regulatory mechanisms to respond to an increase in temperature. Which of the following would NOT represent such a mechanism?

Possible Answers:

Activation of sweat gland excretion

Pilorection of hairs on the skin

Dilation of arteriole sphincters leading to skin capillary beds

Decrease in skeletal muscle activity

Behavioral preference for a cooler environment

Correct answer:

Pilorection of hairs on the skin

Explanation:

This question is asking for a thermoregulatory mechanism that is NOT active in response to an increase in temperature. Preference for a cooler environment would be an apt response to increased temperature. Activation of sweat gland excretion would secrete liquid onto the skin's surface—the evaporation of this liquid carries heat away from the skin. Dilation of arteriole sphincters would increase overall blood flow, which carries heat, to the skin; this heat can dissipate to the environment. Decrease in skeletal muscle activity would lead to less metabolic activity and subsequent heat production.

The pilorection of hairs on the skin surface would not be an appropriate response to a temperature increase. This is because when erect, hairs would reduce the flow of air over the skin and retain body heat. Goosebumps are formed in pilorection, and this is typically seen in a response to cold temperatures.

Example Question #2 : Epithelial Tissue And Integumentary System

Other than acting as a barrier for the body from the environment, the integumentary system is also responsible for thermoregulation. Which of the following occurs when body temperature drops below a certain threshold?

Possible Answers:

The skin secretes sodium, and water passively follows through the process of osmosis

Erector muscles contract and causes hair to lay flat against the skin

Mechanoreceptors in the skin are primed for easier activation of action potentials

The skin opens vital pores, which allow more water exchange

Erector muscles contract and causes hair to stand up

Correct answer:

Erector muscles contract and causes hair to stand up

Explanation:

Beneath the surface of the skin, erector muscles are attached to hairs. When it is cold these muscles contract, causing hair to stand up. When hair stands it creates a collective mass of air that maintains temperature by lowering drafts. The erect hairs essentially dull the effects of convection heat transfer by trapping warm air against the skin.

Example Question #4 : Epithelial Tissue And Integumentary System

The skin is able to contribute to thermoregulation in which of the following ways?

Possible Answers:

Release of chemicals helps to warm the environment

Constriction of blood flow helps lower body temperature

Sweat and its evaporation lower body temperature

Increase in blood flow to skin helps raise body temperature

Constriction of blood vessels keeps body temperature warmer

Correct answer:

Sweat and its evaporation lower body temperature

Explanation:

The skin is part of the integumentary system, and is also partly responsible for thermoregulation.

In warm climates, the skin helps lower body temperature by sweating and promoting vasodilation. It is able to open up pores to secrete sodium, which is followed by chloride and water. When water evaporates on the skin, it lowers the temperature of the skin because the water requires an input of thermal energy to transition to the gaseous state. Vasodilation in hot climates allows blood to exchange heat with the environment by flowing close to the skin.

In cold climates, the skin helps raise body temperature by promoting vasoconstriction and goose bumps (cutis anserina). Vasoconstriction helps prevent heat loss to the environment by reducing blood flow to regions of high surface area. Goose bumps raise the hairs in the skin to prevent convection from transferring heat away from the skin.

Example Question #8 : Epithelial Tissue And Integumentary System

Which of the following is found in sweat?

Possible Answers:

Sodium ions

Sodium and chloride ions

Chloride and potassium  ions

Sodium and potassium ions

Chloride ions

Correct answer:

Sodium and chloride ions

Explanation:

Sweat is produced in response to increased body temperature, which triggers a response from the hypothalamus that increases sweat secretion. Sweat is composed of water, sodium, and chloride ions. The evaporation of the water requires an input of energy (it is an endothermic process). This energy comes from the heat of the body, and is dissipated when the water transitions to the gaseous state. The byproduct is sodium chloride salt.

Example Question #7 : Connective Tissue And Epithelium

One component of the immune system is the neutrophil, a professional phagocyte that consumes invading cells. The neutrophil is ferried to the site of infection via the blood as pre-neutrophils, or monocytes, ready to differentiate as needed to defend their host.

In order to leave the blood and migrate to the tissues, where infection is active, the monocyte undergoes a process called diapedesis. Diapedesis is a process of extravasation, where the monocyte leaves the circulation by moving in between endothelial cells, enters the tissue, and matures into a neutrophil.

Diapedesis is mediated by a class of proteins called selectins, present on the monocyte membrane and the endothelium. These selectins interact, attract the monocyte to the endothelium, and allow the monocytes to roll along the endothelium until they are able to complete diapedesis by leaving the vasculature and entering the tissues.

The image below shows monocytes moving in the blood vessel, "rolling" along the vessel wall, and eventually leaving the vessel to migrate to the site of infection.

 

Untitled

Which of the following is most likely true of the endothelial cells depicted in the passage?

Possible Answers:

Endothelial cells are specialized with surface proteins to promote clotting, preventing uncontrolled bleeding

Endothelial cells are biologically inert, and serve mainly as a barrier to the extravascular space

Endothelial cells are specialized to prevent clotting

Endothelial cells have extensive smooth muscle to allow capillaries to change size

Endothelial cells always have fenestrations to permit gas and nutrient exchange with tissues

Correct answer:

Endothelial cells are specialized to prevent clotting

Explanation:

Endothelial cells are specialized to prevent clotting in their intact form. When disrupted, the endothelium retracts to expose the basement membrane. Proteins in this region will activate the clotting cascade.

Arterioles are the main type of vessel that regulates vessel size and pressure, and exchange over endothlieum can occur with or without fenestrations.

Example Question #10 : Epithelial Tissue And Integumentary System

What is the function of the arrector pili muscles?

Possible Answers:

Constricts the sweat glands

Creates the "shivering" motion

Increases circulation to the skin

Open pores to release toxins

Raises hairs and causes goosebumps

Correct answer:

Raises hairs and causes goosebumps

Explanation:

The arrector pili muscles are responsible for raising the hair shafts, producing "goose bumps" around the follicle. Arrector pili muscles are mostly vestigial, used for thermoregulation in mammals with more fur. In humans, the hair raise function is associated with fear and sexual arousal.

← Previous 1
Learning Tools by Varsity Tutors

Incompatible Browser

Please upgrade or download one of the following browsers to use Instant Tutoring: