The hormone that stimulates the contraction of the uterus during childbirth is:
A. Estrogen
B. Oxytocin
C. Progesterone
D. Prolactin
Answer: Option B
Solution (By JKExamLibrary)
Oxytocin, released from the posterior pituitary, stimulates uterine smooth muscle contractions during parturition (childbirth) and milk ejection during lactation. Prolactin stimulates milk production. Estrogen and progesterone regulate reproductive cycle and maintain pregnancy. Oxytocin is also known as the 'love hormone' and functions through positive feedback during labor.
Explanation:
Pleiotropy is a phenomenon where a single gene influences multiple, seemingly unrelated phenotypic traits. Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by a mutation in a single gene (PAH) that codes for the enzyme phenylalanine hydroxylase. This single mutation leads to multiple effects: intellectual disability, reduced hair and skin pigmentation, and musty odor.
Explanation:
Pneumothorax is the accumulation of air in the pleural space, causing lung collapse. Pneumonia is lung infection, emphysema is alveolar damage, pleurisy is inflammation of pleura. It can be spontaneous or traumatic.
Explanation:
Red tides are harmful algal blooms caused primarily by the rapid multiplication of certain marine dinoflagellates, such as Gonyaulax. These blooms discolor the water red or brown and release potent toxins (like saxitoxin) that can kill marine life and cause paralytic shellfish poisoning in humans who consume contaminated seafood. Cyanobacteria can cause freshwater blooms, but not marine red tides.
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