Question

Human Physiology

1. Describe the pathway of filtrate flow through the urinary system, beginning at the renal corpuscle and ending with elimination from the body. Include in your description the locations where the three major processes occur, and the names and locations of the associated capillaries.
2. Describe the events that lead to micturition (urination), including the effect of the nervous system on the muscles involved.
3. Explain the concept of transport maximum. Under what scenario would glucose appear in the urine?
4. Explain in detail the process that establishes and maintains the medullary osmotic gradient in the kidneys. Then describe the effect this osmotic gradient has on the water in the renal tubules.
5. Explain what conditions stimulate the release of ADH by the posterior pituitary. Then describe in detail the effect of ADH on cells lining the collecting duct.
6. Describe the effect aldosterone and ANP have on sodium levels in the blood.
7. Describe the process by which ingested proteins and carbohydrates are digested, absorbed, and transported into the bloodstream. Then contrast this with the process pertaining to the digestion and absorption of dietary fats (lipids). Include an explanation as to why lipids are processed differently from hydrophilic molecules.
8. Explain the functions of the stomach and describe the features that make it uniquely adapted to its function, including the function of cells located in the gastric pits.
9. Describe the 28-day ovarian cycle (follicle phase & luteal phase), beginning with the development of primary follicles and ending with degeneration of the corpus luteum. Include in your description the role of granulosa cells, theca cells, and the zona pellucida.
10. Describe the pathway that sperm travel during ejaculation, beginning in the testes and ending at the penis. Then name and describe the function of the accessory glands involved in the process.
11. Explain the function of Leydig cells and Sertoli cells in the development of sperm inside the testes.
12. Describe in detail the steps that lead to inflammation, beginning with the introduction of pathogens into a wound, and ending with the formation of a clot. Include in your description the types of cytokines released and the various leukocytes involved. (10 pts.
13. Explain what happens during lymphocyte maturation to ensure B and T lymphocytes do not attack healthy body cells. Include the site of maturation for B cells and for T cells.

Answer 1

1) URINE FORMATION - The urine formation occurs by filtration of blood from the nephrons which are the smallest unit of kidney .

The urine formation involves three processes -

A) GLOMERULAR FILTRATION /ULTRAFILTRATION -

The blood firstly flows from affrent arteriole into the glomerulus from where it enters the bowman's capsule and the filtrate which is formed at this stage is called as glomerular filterate.

physiology - The diameter of afferent arteriole is more than that of efferent arteriole hence the blood pressure in glomerulus increases which causes filteration of blood. At this stage except plasma and blood corpuscles all the blood components are present.

The kidney filters 180 L fluid per day but why do we not excrete out this much of liquid , the answer lies in tubular reabsorption .

B) TUBULAR REABSORPTION - The glomerular filterate reaches to proximal tubules of the nephron here essential nutrients are reabsorbed such as ions like sodium , potassium , calcium and substance like glucose , amino acids and water.

At the end where filterate reaches near collecting duct the anti-diuretic hormone reabsorbs all the excess water and urine concentrates.

C) TUBULAR SECRETION - at this stage the filtrate reaches distal convulated tubule where uric acid is secreted into the filtrate. At the distal most part urea , potassium ions and hydrogen are added to urine.

This way whole urine is formed.

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