Tag: excretion and osmoregulation

In electron transport chain, there are 7 electron acceptors, which are as follows $Co-Q\rightarrow Cyt \,b\rightarrow Cyt \,{c} _{1} \rightarrow Cyt \,c\rightarrow Cyt a\rightarrow Cyt \,{a} _{3}\rightarrow{O} _{2}$. Oxygen is the ultimate electron acceptor. These electron acceptors are present in a specific sequence along inner mitochondrial membrane.

Urine is a liquid excretory product of the body excreted by the kidneys through a process called urination (or micturition) and excreted through the urethra. Urine contains urea and water. A urea is toxic it needs water to be excreted from the body.

The final passageway for urine out of the bladder is through the thin-walled urethra. This tube runs from the base of the urinary bladder to the outside of the body. In the female, it is relatively short, connecting the bladder to the external urethral sphincter. In males, it is longer. It passes through the prostate gland and travels the length of the penis before reaching the external sphincter. 

The blood is filtered by the kidney and the urine is formed. Urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. It is a hollow muscular, and distensible (or elastic) organ. Urine enters the bladder via the ureters and exits via the urethra. 

The urinary system is involved in the excretion of nitrogenous waste products such as urea, uric acid or ammonia. The excretion of nitrogenous waste from animals is important because if it is allowed to build up, it can prove toxic. The waste product is formed due to the breakdown of the amino acids.

The muscular part of the bladder wall is called the detrusor muscle. The internal and external sphincter muscles surround the bladder neck and the urethra. While the bladder is filling, the detrusor muscle is relaxed so the bladder wall can expand, and the sphincter muscles are contracted to keep the urethra closed. Sympathetic stimulation is predominant during bladder filling, and the parasympathetic causes emptying. Thus, option D is correct and other options are wrong.

The feeling of fullness sensation of urine is marked if the volume of urine increases up to 600 c.c.

Urine which is a waste product of the human system is 95% water. Remaining 5% contains urea, uric acid, creatinine, sodium chloride, hormones, carbohydrates, fatty acids, enzymes, mucins and pigments. While diets play a role in the excretory systems, the protein rich diet does not bring in any changes in the uric acid levels in urine.