Question

Which of the following best describes the neuroendocrine-to-endocrine pathway of hormone action?

	a.	A neuron secretes a chemical messenger that travels to a distant gland that subsequently produces a second chemical messenger that travels to a different destination in the body.
	b.	A neuron that produces hormones releases its hormones directly into another gland that it regulates.
	c.	A gland releases hormones directly into a neural structure, thus regulating neural functions.
	d.	A gland exhibits negative feedback on the nervous system by releasing hormones into neural tissue both directly and indirectly through the circulation.

Suppose you discover a new animal that is shaped exactly like a cube. You call this animal Cubus walkerii. Which of the following statements is incorrect regarding Cubus walkerii?

	a.	As the size of Cubus walkerii gets larger, its surface area increases.
	b.	As the size of Cubus walkerii gets larger, its volume increases.
	c.	As the size of Cubus walkerii gets larger, its surface to volume ratio increases
	d.	As the size of Cubus walkerii gets larger, its total metabolic rate (O2 consumed/hr) will increase
	e.	None of the statements above are incorrect.

Which of the following is a correct pair telling WHERE and HOW sodium ions are reabsorbed in the loop of Henle?

	a.	Descending limb, active transport
	b.	Descending limb, passive transport
	c.	Thin ascending limb, active transport
	d.	Thick ascending limb, active transport

The marathon is a 26.2-mile-long, endurance running race. Successful marathon runners will benefit from having leg muscles with __________.

i. fibers with a high concentration of myoglobin

ii. fibers depending on glycolysis for generation of ATP

iii. fibers with relatively low mitochondria content

	a.	None of the above are correct
	b.	Exactly ONE of the above is correct
	c.	Exactly TWO of the above are correct
	d.	All of the above are correct.

Hormone X activates the cAMP second messenger system in its target cells. The greatest response by a cell would come from _____.

	a.	applying a molecule of hormone X to the extracellular fluid surrounding the cell
	b.	injecting a molecule of hormone X into the cytoplasm of the cell
	c.	applying a molecule of cAMP to the extracellular fluid surrounding the cell
	d.	injecting a molecule of cAMP into the cytoplasm of the cell

Odorant molecules activate sensory neurons by

	a.	deflecting the cilia of hair cells, leading to the release of neurtotransmitters.
	b.	binding to rhodopsin, leading to cell depolarization
	c.	passing through ion channels and altering membrane potentials
	d.	binding to membrande-bound receptor proteins of sensory neurons
	e.	altering basilar membrane stiffness to shift response by receptor cells

All of the following statements about a true hormone are correct except:

	a.	They can be modified amino acids, peptides or steroid molecules
	b.	They are used to communicate between different organisms.
	c.	They are carried by the circulatory system
	d.	They elicit specific biological responses from target cells.
	e.	All of the above are correct statements about hormones.

Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber?

1. Tropomyosin shifts and unblocks the cross-bridge binding sites.

2. Calcium is released and binds to the troponin complex.

3. The sarcoplasmic reticulum is depolarized when a wave of depolarization moves from the neuromuscular junction into the cell's interior by way of the transverse tubules.

4. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP.

5. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane at the neuromuscular junction.

	a.	1 → 2 → 3 → 4 → 5
	b.	2 → 1 → 3 → 5 → 4
	c.	3 → 4 → 2 → 1 → 5
	d.	5 → 3 → 1 → 2 → 4
	e.	5 → 3 → 2 → 1 → 4

If a molecule of carbon dioxide enters the blood in your left toe and is exhaled from your nose, it must pass through all of the following EXCEPT ________.

	a.	an alveolus
	b.	the right ventricle
	c.	the pulmonary vein
	d.	the trachea
	e.	the right atrium

A vaccine to the Covid-19 virus ___________________________ .

	a.	will primarily be used to help cure patients that currently have the virus
	b.	will be successfully developed in the future, as all virus infections eventually can be treated with vaccines
	c.	will be able to recognize and neurtalize the Covid-19 virus, before it becomes harmful to an individual
	d.	is an example of how the body's innate immunity to fight disease can be harnessed by scientists in order to fight of invading pathogens.

Answer 1

1. Answer: A neuron secretes a chemical messenger that travels to a distant gland that subsequently produces a second chemical messenger that travels to a different destination in the body

example:

• Hypothalamic–pituitary–thyroid axis( Here hypothalamus releases TRH/thyrotropin releasing hormone and pituitary releases Thyroid Stimulating hormone/TSH and thyroid releases T#3 & T4 in response to it.)

2. answer: Incorrect statement is

As the size of Cubus walkerii gets larger, its surface to volume ratio increases. Because with increase in thw size the surface areas to volume ratio will decrease 6L*L/ L*L*L= 6/L . with increase in L the ratio will decrease.

3. Answer:  

d.Thick ascending limb, active transport Here sodium ions are reabsorbed in the loop of henle via active transport using ATP and heps in maintaining the balance of sodium ion in the blood.

4. answer

b.	Exactly ONE of the above is correct

The correct one is: fibers with a high concentration of myoglobin

moreover in marathon runners it is the slow twitch muscle fibers conataining abundant myogolbin and mitochondria for sustained aerobic respiration.

All the best mate. Cheers!!!!