Digestive glands Questions in English

(C) The $Liver$ is the primary organ responsible for detoxification in the human body.
It processes blood coming from the digestive tract and neutralizes harmful substances, drugs, and toxins, converting them into less harmful compounds that can be excreted from the body.

(C) Bile is synthesized by the liver and stored in the gall bladder. It does not contain any digestive enzymes; instead,it contains bile salts (like sodium glycocholate and sodium taurocholate) and bile pigments (bilirubin and biliverdin). Bile salts are responsible for the emulsification of fats,which increases the surface area for lipase action. Therefore,option $C$ is the correct statement.

(D) The amount of saliva secreted daily in humans ranges from approximately $1000 \ ml$ to $1500 \ ml$ $(1-1.5 \ \text{liters})$.
Saliva is produced by the salivary glands and plays a crucial role in the initial digestion of food and lubrication of the oral cavity.

(D) The pancreas is a vital digestive gland that secretes pancreatic juice into the small intestine.
Pancreatic juice contains various enzymes such as trypsin and chymotrypsin for protein digestion,pancreatic amylase for carbohydrate digestion,and pancreatic lipase for fat digestion.
It also contains nucleases that act on nucleic acids.
If the pancreas is removed,these essential enzymes are no longer secreted into the digestive tract.
Consequently,the digestion of carbohydrates,fats,and proteins is severely impaired or ceases entirely.
Therefore,all of these compounds remain undigested.

(C) Pancreatic juice contains inactive enzymes such as $Trypsinogen$, $Chymotrypsinogen$, and $Procarboxypeptidases$, along with active enzymes like $Lipases$, $Amylases$, and $Nucleases$.
$Trypsinogen$ is an inactive precursor of $Trypsin$.
$Chymotrypsinogen$ is an inactive precursor of $Chymotrypsin$.
$Lipase$ is an active enzyme present in pancreatic juice.
"Parasitic" is not a biological enzyme or component of pancreatic juice, making it the correct answer.

(D) Salivary amylase,also known as ptyalin,is an enzyme that breaks down starch into maltose.
Its enzymatic activity is dependent on the presence of chloride ions $(Cl^-)$,which act as an essential activator or cofactor for the enzyme.
Without $Cl^-$,the catalytic efficiency of salivary amylase is significantly reduced.

(A) Most proteases are secreted in inactive forms known as proenzymes or zymogens.
Propepsin (also known as pepsinogen) is the inactive precursor of the enzyme pepsin.
Similarly,trypsinogen is the inactive precursor of the enzyme trypsin.
Therefore,both propepsin and trypsinogen are inactive forms of proteolytic enzymes.

(B) The correct answer is $B$.
$Cellulase$ is not secreted by the human alimentary canal.
In herbivores,$cellulase$ is produced by symbiotic microorganisms (bacteria and ciliates) present in the gut to digest plant cellulose.
$Sucrase$,$lipase$,and $invertase$ are enzymes secreted by the intestinal mucosa or other parts of the alimentary canal to aid in digestion.

(C) Gastric glands contain three main types of secretory cells: zymogen (also known as chief or peptic) cells,parietal (oxyntic) cells,and mucous cells.
Zymogen or chief cells are responsible for secreting inactive digestive proenzymes,specifically pepsinogen and prorennin.
$HCl$ (Hydrochloric acid),secreted by parietal cells,converts these inactive proenzymes into their active forms,pepsin and rennin,respectively.

(B) Pepsin is a digestive enzyme that breaks down proteins into smaller peptides.
It is secreted by the chief cells (or peptic cells) located in the gastric glands of the stomach.
These cells release an inactive precursor called pepsinogen,which is activated into pepsin in the presence of hydrochloric acid $(HCl)$ secreted by the parietal cells of the stomach.

(B) Enterokinase (also known as enteropeptidase) is an enzyme produced by the cells of the duodenum in the small intestine.
It is a key component of the intestinal juice (succus entericus).
The primary function of enterokinase is to activate trypsinogen into its active form,trypsin,which is essential for protein digestion.
Therefore,it is found in the intestinal juice.

(A) $Rennin$ is a proteolytic enzyme secreted by the gastric glands (chief cells) of the stomach in infants. It is secreted in an inactive form called $Prorennin$. In the presence of $HCl$,$Prorennin$ is converted into its active form,$Rennin$,which helps in the digestion of milk proteins $(Casein)$.

(A) The pancreas secretes digestive enzymes in an inactive form,known as proenzymes or zymogens (e.g.,trypsinogen).
These inactive enzymes are stored within the pancreatic acinar cells.
They are only activated in the lumen of the small intestine (duodenum) by specific enzymes like enterokinase.
This mechanism prevents the self-digestion of the pancreatic tissue,which would otherwise occur if the enzymes were active within the cells.

(C) The $pancreas$ is a heterocrine gland that secretes pancreatic juice into the duodenum.
Pancreatic juice contains various digestive enzymes, including nucleases such as $deoxyribonuclease$ and $ribonuclease$, which are responsible for the digestion of nucleic acids ($DNA$ and $RNA$) into nucleotides.

(D) Carboxypeptidase is a proteolytic enzyme (exopeptidase) that is secreted by the pancreas in an inactive form called procarboxypeptidase.
It is released into the small intestine as part of the pancreatic juice.
Once in the small intestine,it is activated by trypsin to form active carboxypeptidase,which then acts on the carboxyl end of peptide chains to release individual amino acids.

(C) The correct answer is $C$. The mucosa of the mammalian stomach is highly folded. The single-layered mucous membrane of these infoldings forms tubular and often branched gastric glands in the lamina propria. Each gastric gland contains three main types of secretory cells:
$1$. Neck cells (mucus-secreting cells).
$2$. Oxyntic cells (also known as parietal cells,which secrete $HCl$ and Castle's intrinsic factor).
$3$. Zymogen cells (also known as chief cells or peptic cells,which secrete pepsinogen).

(B) The correct answer is $B$.
Bile is a complex,greenish,and alkaline fluid produced by the liver.
It contains bile salts and bile pigments.
In rabbits,the bile juice appears green primarily due to the presence and accumulation of the pigment biliverdin.
Bilirubin is also present,but the characteristic green colour in many herbivores like rabbits is attributed to biliverdin.

(A) Emulsification is the process of breaking down large fat globules into smaller droplets to increase the surface area for the action of enzymes.
Bile,produced by the liver and stored in the gallbladder,contains bile salts (sodium glycocholate and sodium taurocholate).
These bile salts act as emulsifying agents,which break down large fat globules into smaller ones,facilitating the digestion of fats by the enzyme lipase.
Therefore,bile is responsible for the emulsification of fats.

(A) The liver in humans is divided into two principal lobes,the right lobe and the left lobe.
The right lobe is significantly larger than the left lobe.
These two lobes are separated by the falciform ligament.

(C) The right and left hepatic ducts join to form a common hepatic duct. This common hepatic duct then joins with the cystic duct (the duct from the gall bladder) to form the common bile duct,which is scientifically termed as the $Ductus \ choledocus$.

(A) The gastric glands,specifically the fundic glands,contain three primary types of secretory cells: mucous neck cells,zymogenic (chief) cells,and oxyntic (parietal) cells.
Zymogenic cells,also known as chief cells,are the most numerous cells in the fundic glands.
These cells are primarily located in the basal region of the gastric glands and are responsible for secreting proenzymes like pepsinogen and prorennin.

(B) The blood-forming factor of Castle,also known as the Intrinsic Factor,is secreted by the parietal cells of the stomach.
It is a glycoprotein found in the gastric juice that binds to vitamin $B_{12}$ (extrinsic factor) to facilitate its absorption in the ileum of the small intestine.
Therefore,the correct option is $B$.

(C) Mumps is an acute viral infection caused by the $Mumps \ virus$ (a member of the $Paramyxoviridae$ family).
It primarily affects the $parotid$ salivary glands,which are the largest salivary glands located just in front of and below each ear.
The infection leads to painful swelling and inflammation of these glands.

(B) The liver,including the hepatocytes (liver cells),originates from the embryonic endoderm. During embryonic development,the liver bud arises from the foregut endoderm.

(A) The normal brown colour of faeces is primarily due to the presence of bile pigments,specifically stercobilin,which is derived from the breakdown of bilirubin and biliverdin produced by the liver.
If the liver malfunctions or if there is an obstruction in the bile duct,bile pigments do not reach the intestine.
Without these pigments,the stool loses its characteristic brown colour and appears pale,whitish,or clay-coloured.
Therefore,the correct answer is the liver.

(B) 'Mumps' is an acute viral infection caused by the mumps virus (a paramyxovirus).
The primary clinical manifestation of this disease is the painful swelling and inflammation of the $Parotid$ glands,which are the largest salivary glands located just in front of and below each ear.
Therefore,the correct option is $B$.

(A) The stomach lining contains gastric glands.
$1$. Chief cells (also known as peptic or zymogenic cells) secrete the proenzyme pepsinogen.
$2$. Oxyntic cells (also known as parietal cells) secrete hydrochloric acid $(HCl)$ and intrinsic factor.
$3$. Mast cells are involved in immune responses and are not part of the gastric glands.
Therefore,pepsinogen is secreted by the chief cells.

(D) Brunner's glands (also known as duodenal glands) are located in the submucosa of the duodenum.
These glands secrete an alkaline,mucus-rich fluid containing bicarbonate ions.
This secretion helps to neutralize the acidic chyme coming from the stomach and protects the duodenal mucosa from acid damage.
None of the hormones listed in options $A$,$B$,or $C$ are secreted by Brunner's glands.
Therefore,the correct answer is $D$.

(B) The Crypts of Lieberkühn are tubular glands located between the villi of the small intestine.
These glands secrete the intestinal juice,which is also known as $Succus \ entericus$.
$Succus \ entericus$ contains various enzymes like disaccharidases,dipeptidases,lipases,and nucleosidases that help in the final digestion of food components.
Glucagon and insulin are hormones secreted by the pancreas,not by the intestinal glands.

(A) The pancreas secretes digestive enzymes such as trypsinogen,chymotrypsinogen,and procarboxypeptidase in an inactive form,known as zymogens. These inactive precursors prevent the self-digestion of the pancreatic tissue. Trypsinogen is activated into trypsin by the enzyme enterokinase,which is secreted by the intestinal mucosa. This mechanism ensures that the powerful proteolytic enzymes only become active within the lumen of the small intestine,thereby protecting the pancreas from autodigestion.

(A) Glisson's capsule is a thin connective tissue sheath that covers the lobules of the liver.
Each hepatic lobule is covered by a thin connective tissue sheath called the Glisson's capsule.
Therefore,the correct answer is $A$ (Liver).

(A) Pepsinogen is an inactive proenzyme secreted by the chief cells (also known as zymogenic or peptic cells) located in the gastric glands of the stomach lining.
Once secreted,pepsinogen is converted into its active form,pepsin,in the presence of hydrochloric acid $(HCl)$.
$A$. Zymogenic cells (Chief cells) secrete pepsinogen.
$B$. Sertoli cells are found in the testes and support spermatogenesis.
$C$. Islets of Langerhans are found in the pancreas and secrete hormones like insulin and glucagon.
$D$. Hepatocytes are the primary functional cells of the liver.

(C) The liver is the largest gland of the body.
It is composed of structural and functional units called hepatic lobules.
These lobules contain hepatic cells (hepatocytes) arranged in the form of cords.
Therefore,the specific type of cells found in the liver are hepatic cells.

(C) Saliva is produced by the salivary glands and contains water,electrolytes (like $Na^+$,$K^+$,$Cl^-$,and $HCO_3^-$),enzymes (salivary amylase and lingual lipase),mucus,and antimicrobial agents like lysozyme and immunoglobulin $A$ $(IgA)$.
Glucose is not a normal component of saliva in healthy individuals. Therefore,$C$ is the correct answer.

(C) Saliva contains an enzyme called $Lysozyme$.
$Lysozyme$ acts as an antibacterial agent by breaking down the cell walls of certain bacteria,thereby protecting the oral cavity from infections.
$Cerumen$ is earwax,$Chyme$ is the semi-digested food in the stomach,and $Secretin$ is a hormone involved in digestive regulation.

(D) Hepatic cells (hepatocytes) are the primary functional cells of the liver.
These cells are responsible for the production and secretion of bile.
Bile is a digestive juice that helps in the emulsification of fats in the small intestine.
Amylopsin is a pancreatic amylase,trypsin is a pancreatic protease,and lipase is secreted by both the pancreas and the stomach/small intestine.

(B) The enzyme that digests carbohydrates (such as amylase) is secreted by the digestive glands. Specifically,the zymogenic cells (or chief cells) in the gastric glands and the acinar cells of the pancreas secrete various digestive enzymes. Among the given options,the zymogenic cells of the digestive glands are responsible for the secretion of enzymes that aid in the digestion of carbohydrates and other macromolecules.

(A) Pancreatic juice is secreted by the pancreas and contains various digestive enzymes like trypsinogen,chymotrypsinogen,pancreatic amylase,and lipases.
It is alkaline in nature because it contains bicarbonate ions $(HCO_3^-)$,which help neutralize the acidic chyme coming from the stomach into the duodenum.
The alkaline $pH$ (approximately $7.5$ to $8.8$) is essential for the optimal activity of pancreatic enzymes.

(B) The human body has three pairs of salivary glands: the parotid,submandibular,and sublingual glands.
$1$. The parotid glands are the largest salivary glands and are located just below and in front of each ear.
$2$. The submandibular glands are located below the lower jaw.
$3$. The sublingual glands are located below the tongue.
Therefore,the correct location for the parotid glands is below the ear.

(B) Saliva contains an enzyme called salivary amylase,which is also known as $Ptyalin$.
This enzyme is responsible for the chemical digestion of carbohydrates in the mouth.
It breaks down starch into simpler sugars like maltose and dextrin.
Therefore,the correct option is $B$.

(B) Bile is a digestive juice produced by the liver cells (hepatocytes).
After production,it is stored and concentrated in the gall bladder before being released into the small intestine to aid in the emulsification of fats.

(C) The $Liver$ is the largest gland in the human body. It is an accessory organ of the digestive system that performs various essential functions, including the production of bile, detoxification of chemicals, and metabolism of nutrients. It weighs approximately $1.2$ to $1.5 \, kg$ in an adult human.

(A) Ptyalin,also known as salivary amylase,is an enzyme found in saliva.
It is secreted by the salivary glands in the mouth.
Its primary function is to initiate the chemical digestion of starch into simpler sugars like maltose and dextrin in the oral cavity.

(B) Trypsinogen is an inactive proenzyme (zymogen) secreted by the exocrine cells of the $Pancreas$.
It is released into the duodenum as part of the pancreatic juice.
Once in the small intestine, it is activated into its active form, $Trypsin$, by the enzyme $Enterokinase$ (also known as $Enteropeptidase$), which is secreted by the intestinal mucosa.
Therefore, the correct source of secretion for trypsinogen is the pancreas.

(C) The stomach mucosa contains gastric glands. These glands consist of three major types of cells:
$1$. Mucus neck cells which secrete mucus.
$2$. Peptic or chief cells which secrete the proenzyme pepsinogen.
$3$. Parietal or oxyntic cells which secrete $HCl$ (hydrochloric acid) and intrinsic factor (essential for absorption of vitamin $B_{12}$).
Therefore,parietal cells are responsible for the secretion of hydrochloric acid.

(D) Vitamin $B_{12}$ (cyanocobalamin) is essential for the synthesis of $DNA$ and the maturation of red blood cells $(R.B.C.s)$.
$A$ deficiency of vitamin $B_{12}$ leads to pernicious anemia,a condition characterized by the inability of the body to produce mature,healthy $R.B.C.s$.

(C) Bilirubin and biliverdin are bile pigments.
These pigments are formed by the breakdown of hemoglobin from old red blood cells in the liver.
They are excreted into the duodenum along with bile juice,which is produced by the liver and stored in the gallbladder.
Therefore,they are characteristic components of bile juice.

(A) The liver produces bile,which is then stored and concentrated in the gallbladder. Therefore,the statement that bile is secreted by the gallbladder is incorrect,as the gallbladder only stores and releases it,while the liver is the site of secretion.

(A) The stomach lining contains gastric glands.
$1$. Zymogenic cells (also known as chief cells or peptic cells) secrete the proenzyme pepsinogen.
$2$. Oxyntic cells (or parietal cells) secrete $HCl$ and Castle's intrinsic factor.
$3$. Goblet cells secrete mucus,which protects the stomach lining from the corrosive action of $HCl$.
$4$. Insulin is secreted by the beta cells of the Islets of Langerhans in the pancreas,not by salivary glands.
Therefore,the only correct pair is Pepsinogen $\to$ Zymogenic cells.

(C) The $Liver$ is the primary organ responsible for detoxification in the human body.
It processes blood coming from the digestive tract and filters out toxins, drugs, and metabolic waste products.
Through various enzymatic reactions, such as oxidation, reduction, and conjugation, the $Liver$ converts harmful substances into less toxic or water-soluble forms that can be easily excreted by the kidneys.