Parathyroid Gland Questions in English

(C) In humans,there are $4$ parathyroid glands present on the back side of the thyroid gland.
These glands are arranged as one pair in each of the two lobes of the thyroid gland.

(A) The Parathyroid Hormone $(PTH)$ is a peptide hormone secreted by the parathyroid glands.
$(i)$ $PTH$ acts on bones and stimulates the process of bone resorption (dissolution/demineralization),which releases calcium into the blood.
$(ii)$ $PTH$ acts on the kidneys to stimulate the reabsorption of calcium from the renal tubules and suppresses the reabsorption of phosphate.
$(iii)$ $PTH$ increases the absorption of calcium from the digested food in the intestine.
$(iv)$ $PTH$ also influences muscle and nerve activity by maintaining calcium homeostasis,which is essential for proper neuromuscular function.
Therefore,$PTH$ influences the Kidney $(I)$,Bone $(II)$,Muscle $(III)$,and Intestine $(IV)$. The Brain $(V)$ is not directly regulated by $PTH$ in the same manner as the other organs listed.
Thus,the correct option is $A$.

(A) The flow chart shows that hormone $X$ is released in response to low blood calcium levels and acts to increase calcium levels in the blood.
$TCT$ (Thyrocalcitonin) is a hormone secreted by the thyroid gland that lowers blood calcium levels.
$PTH$ (Parathyroid Hormone) is secreted by the parathyroid glands in response to low blood calcium levels. It acts to increase blood calcium levels by stimulating bone resorption (dissolution),increasing calcium reabsorption by the renal tubules,and increasing calcium absorption from the digested food in the intestine.
Therefore,the hormone $X$ is $PTH$.

(C) Ram has a high level of calcium in his blood (hypercalcemia).
This condition is primarily caused by an excess of $Parathormone$ $(PTH)$,which is secreted by the parathyroid glands.
$PTH$ increases blood calcium levels by stimulating osteoclast activity (bone resorption),increasing calcium reabsorption in the renal tubules,and promoting calcium absorption from the digestive tract.
$Thyrocalcitonin$ $(TCT)$ has an antagonistic effect to $PTH$,meaning it lowers blood calcium levels.
Growth hormone and insulin do not primarily regulate blood calcium levels in this manner.

(D) The excitability of nerves and muscles is regulated by the concentration of ions,particularly $Ca^{2+}$.
Parathyroid hormone $(PTH)$ is a hypercalcemic hormone,meaning it increases blood $Ca^{2+}$ levels by stimulating bone resorption (osteoclast activity).
$A$ decrease in $PTH$ activity (hypoactivity) leads to hypocalcemia,which is a low level of $Ca^{2+}$ in the blood.
Low levels of $Ca^{2+}$ lower the threshold for nerve impulse generation,thereby increasing the excitability of nerves and muscles.
This increased excitability results in sustained contractions or spasms of the muscles of the larynx,face,hands,and feet,a condition known as tetany.

(A) Parathyroid hormone $(PTH)$ is a peptide hormone secreted by the parathyroid gland that plays a crucial role in calcium homeostasis.
$1$. It stimulates the process of bone resorption (demineralization),which releases calcium into the blood. Thus,statement $(a)$ is an effect of $PTH$.
$2$. It increases $Ca^{2+}$ levels in the blood (hypercalcemic hormone). Thus,statement $(b)$ is $NOT$ an effect of $PTH$.
$3$. It stimulates the reabsorption of $Ca^{2+}$ by the renal tubules. Thus,statement $(c)$ is an effect of $PTH$.
$4$. It increases the absorption of $Ca^{2+}$ from digested food by stimulating the synthesis of active Vitamin $D$. Thus,statement $(d)$ is $NOT$ an effect of $PTH$.
$5$. $PTH$ does not directly increase the metabolism of carbohydrates. Thus,statement $(e)$ is $NOT$ an effect of $PTH$.
Therefore,the statements that are $NOT$ the effects of $PTH$ are $(b), (d)$,and $(e)$.

(A) Tetany is a condition characterized by involuntary muscle contractions or spasms.
It is primarily caused by hypocalcemia,which is a low level of calcium in the blood.
$PTH$ (Parathyroid Hormone) is responsible for increasing blood calcium levels by stimulating bone resorption and calcium reabsorption in the kidneys.
$A$ deficiency or decreased level of $PTH$ leads to low blood calcium levels $(hypocalcemia)$,which causes increased neuromuscular excitability,resulting in tetany.

(A) The hormone $PTH$ (Parathyroid Hormone) is known as a hypercalcemic hormone.
It increases the levels of calcium ions $(Ca^{2+})$ in the blood.
It acts on bones and stimulates the process of bone resorption (dissolution/demineralization).
It also stimulates the reabsorption of $Ca^{2+}$ by the renal tubules and increases $Ca^{2+}$ absorption from the digested food in the intestine.

(C) The human body contains one pituitary gland,one hypothalamus,and one thymus gland.
However,there are four parathyroid glands located on the back side of the thyroid gland (two pairs).
Therefore,in terms of number,the parathyroid glands are the most numerous among the options provided.

(C) The figure shows the thyroid gland with four small glands embedded on its posterior surface,labeled as '$P$'. These are the parathyroid glands.
Parathyroid glands secrete a peptide hormone called Parathyroid Hormone $(PTH)$.
The main function of $PTH$ is to increase the $Ca^{2+}$ levels in the blood by acting on bones (stimulating bone resorption),kidneys (increasing reabsorption of calcium),and the intestine (increasing absorption of calcium from digested food).
Therefore,the correct function is to increase the calcium level in the blood.

(B) $PTH$ (Parathyroid Hormone) is a peptide hormone secreted by the parathyroid glands. Its primary function is to increase the level of calcium ions $(Ca^{2+})$ in the blood. It acts on bones to stimulate the process of bone resorption (dissolution/demineralization) and also stimulates the reabsorption of $Ca^{2+}$ by the renal tubules and increases $Ca^{2+}$ absorption from the digested food. Therefore,if the secretion of $PTH$ decreases (hypoparathyroidism),the blood calcium levels will drop,leading to hypocalcemia.

(C) Hypoparathyroidism is a condition characterized by low levels of parathyroid hormone $(PTH)$.
$PTH$ is responsible for increasing blood calcium levels by stimulating bone resorption and increasing calcium reabsorption in the kidneys.
When $PTH$ levels are low,blood calcium levels drop significantly (hypocalcemia).
This reduction in blood calcium leads to increased neuromuscular excitability,resulting in involuntary muscle spasms or contractions known as tetany.

(C) The condition described is $Osteoporosis$,which is characterized by a decrease in bone mass and increased fragility of bones.
It is common in post-menopausal women due to a decrease in estrogen levels,which leads to increased bone resorption.
Parathormone $(PTH)$ is a hormone that increases blood calcium levels by stimulating bone resorption (demineralization).
Therefore,excessive secretion $(hypersecretion)$ of parathormone leads to excessive removal of calcium from the bones,causing them to become soft and brittle.

(C) The hormone $PTH$ (Parathyroid Hormone) is known as a hypercalcemic hormone.
It increases the blood calcium levels $(Ca^{2+})$ in the body.
$PTH$ acts on bones and stimulates the process of bone resorption (dissolution/demineralization).
It also stimulates the reabsorption of $Ca^{2+}$ by the renal tubules and increases $Ca^{2+}$ absorption from the digested food in the intestine.
Conversely,$TCT$ (Thyrocalcitonin) is a hypocalcemic hormone that lowers blood calcium levels.