High School Biology : Endocrine System

Study concepts, example questions & explanations for High School Biology

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Example Questions

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Example Question #1 : Endocrine System

Which of the following details is not true concerning hormones?

Possible Answers:

Hormones act on receptors all throughout the body

Hormones are released into the bloodstream

Hormones act very quickly in the body

Hormones attach to receptors in order to function

Correct answer:

Hormones act very quickly in the body

Explanation:

When thinking of hormones, it helps to remember that they are generally slow acting, affect all types of tissues at once, and can last for long periods of time in the body. As a result, hormones would not be described as fast-acting in the body.

In contrast, neurotransmitters are generally considered fast-acting, as they are released to a small, targeted area and elicit an immediate response.

Example Question #1 : Endocrine System

Which of the following hormones is NOT released by the pituitary gland?

Possible Answers:

Oxytocin

Thyroid-stimulating hormone

Calcitonin

Follicle-stimulating hormone

Correct answer:

Calcitonin

Explanation:

The pituitary gland is composed of an anterior and a posterior pituitary lobe, both of which are responsible for the secretion of various hormones.

The anterior pituitary secretes thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), prolactin, luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), and growth hormone (GH). It can help to remember these hormones with the pneumonic "FLAT PEG."

The posterior pituitary secretes oxytocin and antidiuretic hormone (ADH). Antidiuretic hormone is also known as vasopressin.

Calcitonin is secreted by the thyroid gland, not the pituitary.

Example Question #1 : Endocrine System

Which of the following is true about endocrine glands?

Possible Answers:

Sweat glands are examples of endocrine glands.

Some endocrine glands' products are secreted into the gastrointestinal tract to aid in breaking down food.

None of the other answers is true.

They may only secrete their products into the bloodstream.

They may secrete their products either into the blood or outside the body.

Correct answer:

They may only secrete their products into the bloodstream.

Explanation:

Endocrine glands only secrete their products into the blood. Sweat glands secrete sweat outside the body and never touch the blood. Similarly, anything inside the gastrointestinal tract is technically outside the body! For something (broken-down food molecules, water, salts etc.) to enter the body, it must be absorbed across the walls of the gastrointestinal tract. Remember, humans are like hollow cylinders in the sense that we have a tube from mouth to anus, which is considered outside the body. 

Example Question #1 : Understanding Glands

Which of the following is not an endocrine organ?

Possible Answers:

Uterus

Ovary

Parathyroid

Pineal body

Thyroid

Correct answer:

Uterus

Explanation:

Endocrine glands are glands of the endocrine system that secrete hormones (their products) directly into the blood rather than through a duct (exocrine organs use ducts). The major glands of the endocrine system include: adrenal glands, hypothalamus, parathyroid glands, thyroid gland, testes, ovaries, pancreas, pituitary gland, and pineal gland. The hypothalamus and pituitary gland are considered neuroendocrine organs. The pineal gland is located in the brain and secretes the hormone melatonin, which helps regulate the circadian (sleep-wake) cycle, especially before sleep.

Example Question #1 : Endocrine System

Which of the following is not a hormone released by the adrenal cortex?

Possible Answers:

Cortisol

Androgens

Vasopressin

Aldosterone

Testosterone

Correct answer:

Vasopressin

Explanation:

The adrenal cortex has three zones. The first zone releases aldosterone, the second releases cortisol, and the third releases androgens, which includes testosterone. Vasopressin (antidiuretic hormone) is synthesized by the hypothalamus and released by the posterior pituitary. 

Example Question #1 : Endocrine System

Catecholamines (epinephrine and norepinephrine) are secreted by the __________.

Possible Answers:

adrenal medulla

parathyroid gland

thymus

kidney

thyroid gland

Correct answer:

adrenal medulla

Explanation:

The adrenal medulla is very different from the adrenal cortex and has a different origin as well. It is made of chromaffin cells, which are neuroendocrine cells, and release catecholamines (epinephrine and norepinephrine), in response to sympathetic stimulation. 

Example Question #1 : Endocrine System

The adrenal gland has 3 layers, each layer secreting its own specific hormone. Which hormone from the anterior pituitary is responsible for stimulating the adrenal glands? 

Possible Answers:

Adrenocorticotropic hormone

Prolactin

Oxytocin 

Vasopressin

Correct answer:

Adrenocorticotropic hormone

Explanation:

Adrenocorticotropic hormone (ACTH) helps stimulate the release of cortisol from the adrenal glands. Vasopressin and oxytocin are produced by the hypothalamus and secreted by the posterior pituitary. Growth hormone and prolactin have no direct effect on the adrenal glands. 

Example Question #1 : Understanding Specific Hormones

How does antidiuretic hormone perform its function?

Possible Answers:

Constricts the ureter to keep fluids from flowing into the bladder

Expands the bladder so that more urine can be carried by the body

Reabsorbs salts so that water passively diffuses out of the filtrate

Constricts the kidneys to keep them from filtering blood

Makes the collecting duct permeable so that water can exit the filtrate

Correct answer:

Makes the collecting duct permeable so that water can exit the filtrate

Explanation:

Antidiuretic hormone (ADH) is a hormone released by the posterior pituitary when there is an imbalance of water in the body. Its function is the same as aldosterone, which also helps regulate water levels in the body. ADH causes channels to open in the collecting duct for water to exit the filtrate and enter the blood, increasing blood volume and retaining water.

In contrast, aldosterone causes channels to open for sodium to exit the filtrate and enter the blood. The blood becomes more concentrated, which draws water out of the filtrate to help dilute the increased sodium levels. This also leads to increased blood volume and water retention.

Example Question #41 : Organs And Organ Systems

Which of the following hormones has the opposite effect of parathyroid hormone?

Possible Answers:

Insulin

Glucagon

Antidiuretic hormone

Calcitonin

Correct answer:

Calcitonin

Explanation:

Parathyroid hormone is responsible for increasing blood calcium levels. Calcitonin has the opposite effect, and lowers blood calcium levels. These two hormones act in a negative feedback loop to keep calcium levels relatively constant. When calcium levels are high, calcitonin is released. When calcium levels are low, parathyroid hormone is released.

Insulin serves to low blood glucose levels, while glucagon acts to increase blood glucose. Antidiuretic hormone (ADH) helps conserve water in the body by increasing water reabsorption in the kidneys.

Example Question #751 : High School Biology

The primary function of insulin is __________.

Possible Answers:

to decrease blood sugar levels

to increase blood sugar levels

to stimulate uptake of glucose by cells

to stimulate the fight or flight response

Two of these answers are correct.

Correct answer:

Two of these answers are correct.

Explanation:

Insulin stimulates the reuptake of glucose from the blood into the cells. Thus, the glucose levels in the blood decrease, as the glucose is taken into cells. The cells may either store it as glycogen (in liver and skeletal muscle) or use it in glycolysis to make ATP.

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