Question

25. Lower than normal NaCl concentration in the ascending limb of the nephron loop will cause the afferent arterioles to what? a. Vasoconstrict b. Vasodilate c. neither 26. Which of the following substances is not found in normal renal filtrate? a. Water and small solutes b. Nitrogenous wastes, such as urea c. Blood cells and large proteins ! d. Ions, such as sodium and potassium 27. The is a passageway for discharging urine from the body. a, ureter b. fallopian tubes c. cystic duct d. urethra 28. The muscle contracts to push urine into the urethra. a. detrusor b. intercostals c. diaphragm d. gluteus muscle and hence is 29. The internal urethral sphincter is made of under control a. smooth, voluntary b. smooth, involuntary c. cardiac, involuntary d. skeletal, voluntary 30. The voluntarily controls the opening and closing of the urethra. a. internal urethral sphincter b. external urethral sphincter c. perineal muscle d. rectus urinus 31. If a substance is secreted, it is most likely going to be a. returned to the blood b. excreted c. remain in the kidneys

Answer 1

25. b) vasodilate.

Decreased NaCL in the asscending limb is sensed by the macula densa cells as decrease in GFR, in response to this the afferent arteriole is vasodilated to increase the GFR, this known as tubulo glomerular mechanism

26.c) blood cells and large proteins.

The size of the filtration slits restricts the passage of large molecules (such as albumin) and cells (such as red blood cells and platelets) that are the non-filterable components of blood.

27.d) urethra.

28. a) detrusor muscle

The detrusor muscle remains relaxed to allow the bladder to store urine, and contracts during urination to release urine

29.b) smooth and involuntary.

30. a) internal urethral sphincter

The internal sphincter is a continuation of the detrusor muscle and is made of smooth muscle, therefore it is under involuntary or autonomic control.

31. b) excreted