EXCRETORY SYSTEM

The job of the excretory system is to remove various wastes produced by the body. The removal process is known as excretion.

The wastes produced by the body : - Carbon dioxide - Water - Nitrogenous wastes - Mineral Salts: (NaCl , KSO4)

Ammonia Urea Uric Acid

Functions of Excretion1. To Regulate the chemical

makeup of the blood and body fluids by removing wastes and excess materials.

2. To maintain a constant body temperature by removing excess heat.

3. To maintain the homeostasis (internal balance) together with the circulatory, nervous and endocrine system

Human Urinary System

The urinary system includes the

- Kidneys,

- Ureter,

- Urinary bladder,

- Urethra.

Functions of Kidneys•They remove the wastes of cellular metabolism from the blood.

•They control the concentrations of the various substances found in the body fluids.

The kidneys filter metabolic wastes and various other substances from the blood, producing urine.

Two tubes, the ureters, carry the urine to the urinary bladder, where it is stored temporarily.

Another tube, the urethra, carries the urine from the bladder to the outside of the body.

Structure of KidneyThe kidney is divided into three distinct regions.

•The outermost region is the cortex,

•the middle region is the medulla, and

•the inner region is the

pelvis.

The filtering of the blood occurs in the cortex; The medulla consists of collecting ducts that carry the urine; and The pelvis is a cavity connected to the ureter, into which the urine drains

Structure of Nephron

•The functional units of the kidneys are the nephrons.

•A cluster of Blood capillaries, the glomerulus,

•It is surrounded by Bowman's capsule.

Four functions of the kidney

- proximal proximal convoluted convoluted tubuletubule- loop of Henleloop of Henle - distal distal convoluted convoluted tubuletubule- collecting ductcollecting duct

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Blood enters the kidneys through the renal arteries. It leaves the kidneys through the renal veins.

MEIOSIS

QUIZ

1.What is the job of excretory system?

2.What are the functions of excretory system?

3. What are the metabolic wastes?

4. What are the excretory organs in human body?

5. List the parts of human urinary system?

6. List the three parts of kidneys

7.Which part of kidney is the functional unit

8. Describe the structure of a nephron

Cytokinesis

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