Biology

Human Physiology and Anatomy

2,235 Questions

Human physiology and anatomy explore the structural organization and biological functions of the human body and its systems. Questions focus on the primary roles of organs, hormones, cellular components, and developmental processes. These fundamentals are integral to medical entrance tests and general science sections.

Organ functionsHormone functionsImmune system rolesDigestive systemCellular functions

Human Physiology and Anatomy Questions

Multiple choice evs science of kitchen balanced diet and malnutrition assimilation of food components and importance of food skeletal system and muscles assimilation of food and egestion busy at work - our internal organs

An uncontrolled reflex is 

  1. Vomiting

  2. Nausea

  3. Constipation

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Vomiting is a process of forcefully expelling the contents of the stomach out of the mouth. It is an involuntary process which means it is an uncontrolled reflex controlled by autonomic nervous system of brain.
So, the correct answer is 'Vomiting'.
Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

When the output of a pathway inhibits inputs to the pathway. This condition is known as

  1. Positive feedback

  2. Negative feedback

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An increased amount of thyroxine in the blood exerts an inhibitory effect on the hypothalamus. in such a way that less of thyroid releasing hormone (TRH) and thyroid stimulating hormone (TSH) is produced respectively. This eventually results in a decrease in thyroxine. This is called negative feedback control. 

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Positive feedback inhibition is concerned about

  1. Increase in input

  2. Increase in output

  3. Bringing back output to the normal level

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • A feedback mechanism for multistep reactions is a biological occurrence wherein the output of a system amplifies the system (positive feedback) or inhibits the system (negative feedback).
  • For example, Release of estrogen(input) from the ovaries stimulates the secretion of GnRH from Hypothalamus which in turn stimulates the secretion of LH(product) from the anterior pituitary. This LH further causes the release of more estrogen(input) from the ovaries. Hence increase in input . Thus positive feedback.
  • Hence  Positive feedback inhibition is concerned about Increase in the input.
  • So, the correct answer is 'Increase in input'.
Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Choose the correct answer from the alternatives givens.
In a negative feedback mechanism:

  1. the output cancels the input

  2. there is a fluctuation above and below the average

  3. there is self-regulation

  4. a regulatory center communicates with other body parts
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Negative feedback, a self-regulated process occurs when some function of the output of a system process, or mechanism is fed back in a manner that tends to reduce the fluctuation in the output whether caused by the changes in the input or by other disturbance.

So, the correct answer is 'there is self-regulation'

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of the following is an example of a negative feedback?

  1. Sucking reflex

  2. Uterine contractions during labour

  3. Secretion of CRH in response to ACTH

  4. Hair erection due to low body temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

One distinctive feature of hormones whose secretion is regulated through the hypothalamus and pituitary is that they regulate their own secretion through negative feedback inhibition. CRH (corticotropin releasing hormone) and ACTH (adrenocorticotropic hormone). Less tropic hormone secretion leads to less stimulation of cortisol secretion by cells of the zona fasciculata of the adrenal cortex. The usefulness of negative feedback inhibition is that it works to keep hormone levels within a particular appropriate physiological range.  The reduced negative feedback inhibition means that more CRH and ACTH will be secreted. More ACTH will stimulate the remaining adrenal tissue to grow and to secrete more cortisol. This will have the effect of bringing cortisol back up towards its normal daily level of secretion.

So the correct option is ' secretion of CRH in response to ACTH'

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which one is a positive feedback mechanism?

  1. Sexual stimulation

  2. Allosteric inhibition

  3. Blood pressure

  4. Perspiration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Allosteric inhibition is the regulation of an enzyme by an effector molecule that binds to a site other than the active site, which is called allosteric site. Since it is not blocking the active site it is called 'positive feedback' option $(B)$

Multiple choice biology chemical coordination and integration mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

An example of negative feed back loop in humans is 

  1. Salivation of mouth at the sight of delicious food.

  2. Constriction of skin blood vessels and contraction of skeletal muscles in cold.

  3. Secretion of tears on dust particles falling in eyes.

  4. Secretion of sweat glands and constriction of skin blood vessels when it is too hot.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Negative feedback is a reaction that causes a decrease in function. It occurs in response to some kind of stimulus. Often it causes the output of a system to be lessened; so, the feedback tends to stabilize the system. This can be referred to as homeostasis. For example, constriction of skin blood vessels and contraction of skeletal muscles in cold.
  • So, the correct answer is 'Constriction of skin blood vessels and contraction of skeletal muscles in cold'.
Multiple choice physics human eye and colourful world human eye and its working what is inside our eyes? human eye and defects of vision

A series of fast moving still pictures can create an illusion of movement because :

  1. The eye can focus on very rapidly changing pictures

  2. Eye is quicker than the brain

  3. Eye can separate two images only when the interval of separation between them is one-tenth of a second

  4. The optical cortex can see through the rapidly moving images.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Human brain needs some time to process the images. It has the ability to see two distinct images only if the separation between them is one-tenth of a second, otherwise an illusion of continuity is created.

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

During blood clotting, fibrin is produced by

  1. Thrombokinase

  2. Prothrombin

  3. Liver

  4. Proteolysis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
During the process of blood clotting, platelets release thromboplastin which converts prothrombin into thrombin. This thrombin in the presence of calcium ions is responsible for conversion of fibrinogen into insoluble fibrin, thus forming a clot
So, the correct answer is 'Prothrombin'
Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

During blood clotting, which of the following is used?

  1. Co
  2. $Ca^{++}$
  3. $Na^+$
  4. $Cl^-$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Blood clotting (coagulation) is the process by which blood vessels repair ruptures after injury. Calcium works together with vitamin K and a protein, called as fibrinogen in the clotting cascade, which forms fibrin. The fibrin hardens very quickly to form a scab over the wound. 

Hence, correct answer is option B.

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

In human, the prothrombin required for blood clotting is produced in

  1. Liver

  2. Stomach

  3. Pancreas

  4. Spleen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Prothrombin is a plasma glycoprotein produced in the liver. It gets converted into thrombin by a clotting factor prothrombinase which further transforms fibrinogen into fibrin which combines with platelets to form clot. 

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Thrombin occurs in vertebrates in 

  1. The blood and gives it red colour

  2. The blood and is important for clotting

  3. The liver and is important for bile secretion

  4. The stomach and digests proteins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Thrombin is a substance formed in one of the steps of clotting process from prothrombin. Thrombin, in turn, converts fibrinogen into fibrin which ultimately forms a clot. 
Thus, the correct answer is option B. 
Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Which enzyme induces lysis of fibrinogen to fibrin during fibrinolysis?

  1. Plasmin

  2. Thrombin

  3. Fibrin

  4. Trypsin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Blood-clotting proteins circulate in the blood plasma in an inactive form, poised to participate in blood coagulation upon tissue injury. Blood-clotting proteins generate thrombin, an enzyme that converts fibrinogen to fibrin, and a reaction that leads to the formation of a fibrin clot.

Therefore, the correct answer is option B.

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Enzyme causing lysis of fibrin during fibrinolysis is

  1. Fibrinogen

  2. Plasmin

  3. Thrombin

  4. VIII Platelet factor
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Fibrinolysis is a process that prevents blood clots from growing and becoming problematic. This process has two types: primary fibrinolysis and secondary fibrinolysis. The primary type is a normal body process, whereas secondary fibrinolysis is the breakdown of clots due to a medicine, a medical disorder, or some other causes. In fibrinolysis, a fibrin clot, the product of coagulation, is broken down. Its main enzyme plasmin cuts the fibrin mesh at various places, leading to the production of circulating fragments that are cleared by other proteases or by the kidney and liver. Hence Enzyme causing lysis of fibrin during fibrinolysis is plasmin.

So, the correct answer is 'Plasmin'.