NEET Biology Excretory Products and their Elimination
Excretory Products and Their Elimination PDF Notes, Important Questions and Synopsis
- Excretion is the process by which living organisms get rid of waste substances either totally or partially accumulated during metabolic activities.
- Modes of Excretion in Animals
- Organs of Excretion in Animals
- Contractile vacuole
- Body surface
- Body surface
- Protonephridia or flame cells
- Tube feet and dermal branchiae
- Urine Formation
Counter Current Mechanism
- In the two limbs of the loop of Henle, urine flows in the opposite direction which forms a
- counter current.
- Similarly, the flow of blood in the two limbs of the vasa recta are also in the counter current pattern.
- This system of a liquid flowing in the two limbs in two opposite directions is termed the counter
- current mechanism.
- It helps to maintain the concentration gradient in the renal medulla and hence helps in concentrating urine in the loop of Henle.
- Regulation of Kidney Function
Neural Control Hormonal Control
When the systemic blood pressure increases, the afferent arteriole narrows down which decreases GFR.
- Nerve fibres of the sympathetic nervous system innervate the blood vessels of the kidneys which decreases GFR.
- Anti-diuretic hormone (ADH)
- Atrial natriuretic factor (ANF)
The process of release of urine is called micturition.
Role of Other Excretory Organs
- Excrete sweat
- Remove carbon dioxide and water vapour
Eliminates cholesterol, inactivated products of steroid hormones, vitamins and drugs
- Removes salts such as calcium phosphate
- A man has taken Large amount of proteins in his diet, will have in urine ? Options: 1. More salts and water 2. More urea 3. Little fat 4. Little glucose and excess urea
- In this picture in NCERT, in the PCT region, they have shown K+ ion as being reabsorped. But infact, it is secreted INTO the PCT right? So isn't this given in NCERT, a mistake?
- ⭕ Explain the answer of this question..⭕ Thanks☺️
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