Histology Mid Year 1

Melatonin is a hormone produced by the pineal gland in the brain that regulates sleep-wake cycles. It is not involved in the regulation of calcium metabolism. Vitamin D, calcitonin, and parathyroid hormone, on the other hand, all play important roles in maintaining calcium homeostasis in the body. Vitamin D helps in the absorption of calcium from the intestines, calcitonin helps to decrease blood calcium levels, and parathyroid hormone helps to increase blood calcium levels.

The question asks for an accessory gland, which means a gland that aids in the function of another organ. The prostate, bulbourethral gland, and seminal vesicles are all accessory glands that produce fluids that are necessary for the functioning of the reproductive system. However, the penis is not a gland, but rather an external reproductive organ. It does not produce any fluids and therefore is not considered an accessory gland.

Oxytocin is not secreted by chromophils. Chromophils are cells in the anterior pituitary gland that secrete hormones such as ACTH, TSH, FSH, and LH. Oxytocin is produced by the hypothalamus and released by the posterior pituitary gland. It plays a role in childbirth, lactation, and social bonding, but it is not secreted by chromophils.

Zona glomerulosa cells are known for their role in secreting mineralocorticoids, which are a type of steroid hormone. These hormones, such as aldosterone, play a crucial role in regulating electrolyte and fluid balance in the body. The presence of smooth endoplasmic reticulum (SER) in these cells is indicative of their high synthetic activity, as SER is involved in the production of lipids and steroids. Therefore, the fact that Zona glomerulosa cells with E/M are rich in SER suggests that they secrete steroid hormones rather than proteins, enzymes, or glycoproteins.

The zona reticularis is a region in the adrenal cortex responsible for secreting androgens, such as testosterone. Androgens play a crucial role in the development and maintenance of male characteristics, as well as contributing to female sexual function. They are also involved in various physiological processes, including the regulation of muscle mass, bone density, and red blood cell production. Therefore, it is accurate to say that the zona reticularis secretes androgens.

Sertoli cells are responsible for producing Inhibin and Androgen binding protein. Inhibin is a hormone that regulates the production of follicle-stimulating hormone (FSH) in the pituitary gland, while Androgen binding protein helps in the transport and concentration of testosterone in the seminiferous tubules. Therefore, both options a and b are correct as they represent the products of Sertoli cells.

The vas deferens is a tube that carries sperm from the testicles to the urethra. It is composed of three layers of smooth muscle. The inner layer is circular, the middle layer is longitudinal, and the outer layer is also circular. These layers of smooth muscle work together to help propel sperm through the vas deferens during ejaculation.

The bulbourethral glands are a pair of small glands located below the prostate gland in males. These glands secrete a clear, slippery fluid that helps to lubricate the urethra and neutralize any traces of acidic urine that may remain in the urethra. The ducts of the bulbourethral glands open into the penile urethra, which is the final part of the urethra that runs through the penis. This allows the fluid from the bulbourethral glands to mix with semen during ejaculation and provide lubrication for the passage of sperm through the urethra.

The distal convoluted tubules are under the control of all of the above hormones. Aldosterone hormone regulates sodium reabsorption and potassium secretion in the distal convoluted tubules. Atrial natriuretic factor promotes sodium and water excretion in the distal convoluted tubules. Anti-diuretic hormone regulates water reabsorption in the distal convoluted tubules. Therefore, all three hormones have an effect on the distal convoluted tubules, making the correct answer "all of the above."

The renal corpuscle is a structure in the kidney that is responsible for the initial filtration of blood. It consists of two main components: the glomerulus and the Bowman's capsule. The glomerulus is a network of capillaries that allows for the filtration of blood, while the Bowman's capsule surrounds the glomerulus and collects the filtrate. Mesangial cells are found in the renal corpuscle and help to support the structure and regulate blood flow. Filtration slits are also present in the renal corpuscle and allow for the passage of filtrate into the Bowman's capsule. However, the macula densa is not found in the renal corpuscle. It is a specialized region of the distal convoluted tubule that plays a role in regulating blood pressure and filtration rate.

The correct answer is renal columns of Bertini. The renal columns of Bertini are collections of cortical tissue found between the medullary pyramids in the kidney. These columns extend into the medulla and separate the renal pyramids. They contain blood vessels, urinary tubules, and interstitial cells. The medullary ray refers to the structures found in the medulla of the kidney, while the interlobular cortex refers to the region of the cortex between the renal lobes. Therefore, neither of these options accurately describes the collections of cortical tissue found between the medullary pyramids.

The correct answer is extracellular in the follicular lumen. The iodination of thyroglobulin occurs outside of the follicular cell, specifically in the follicular lumen. This is where the thyroid hormone synthesis takes place. Thyroglobulin, a protein produced by the follicular cells, is transported into the follicular lumen where it is iodinated by the enzyme thyroid peroxidase. This iodination process is essential for the production of thyroid hormones, such as thyroxine (T4) and triiodothyronine (T3).

The seminal vesicles are considered part of the male reproductive system, specifically the male genital duct system. They are responsible for producing and storing a significant portion of the semen. The rete testis, tubuli recti, and ductus deferens are all components of the male genital duct system as well, involved in the transportation and storage of sperm. Therefore, the correct answer is the seminal vesicles.

Basophils are a type of white blood cells that are larger in size compared to acidophils. They are also known to stain strongly with periodic acid-Schiff (PAS) stain. Therefore, option A&C is the correct answer as it states both these characteristics of basophils.

The juxta_glomerular cells are modified smooth muscles that are found in the wall of the afferent arterioles, not the distal convoluted tubules. They are innervated by adrenergic nerve fibers and contain a well-developed RER and golgi complex.

Corpora amylacea are spherical structures that are seen in some prostatic alveoli. They are composed of concentric layers of glycoproteins and polysaccharides. These structures are commonly found in the prostate gland and are believed to be a result of aging and degeneration. They are typically benign and do not cause any significant health issues. Psammoma bodies, corpora arenacea, and Hassall's corpuscles are different structures found in other parts of the body and are not related to the prostate gland.

The correct answer is "they are fenestrated with diaphragm." This means that endothelial cells of the glomerular capillaries do not have fenestrations or small pores with diaphragms. Fenestrations are present in other types of endothelial cells, but not in the glomerular capillaries. The other statements are true, as the endothelial cells are in close proximity to the secondary processes of podocytes, rest on a basal lamina formed by themselves and podocytes, and play a role in the renal blood barrier.

The zona fasciculata is a layer of the adrenal cortex that produces glucocorticoid hormones. It is known for containing abundant SER (smooth endoplasmic reticulum) which is responsible for the synthesis of lipids, including cholesterol, which is a precursor for steroid hormones. It also contains mitochondria with lobular cristae, which are involved in energy production. Additionally, the zona fasciculata stores lipids in the form of lipid droplets. However, it does not contain glycogen granules, as glycogen storage is not a characteristic of this layer.

The statement "efferent artery belongs to the juxta_glomerular apparatus" is incorrect. The efferent artery does not belong to the juxta_glomerular apparatus. The juxta_glomerular apparatus is composed of specialized cells located near the glomerulus, including the macula densa and the juxtaglomerular cells. The efferent artery is the blood vessel that carries blood away from the glomerulus.

Leyding cells resemble adreno-cortical cells. The question is asking about the type of cells that Leyding cells resemble, and the correct answer is adreno-cortical cells.

The urinary bladder is lined with transitional epithelium, not simple columnar epithelium. It has three layers of muscle, not two. And it is covered by serosa, not adventitia. Therefore, none of the above options are correct.