13.2.1 The human kidney

The Excretory System1.   The excretory system plays an important role in homeostasis.2.   The primary organs of the excretory system are kidneys. The human kidney1.   The kidneys filter blood and form urinewhich exits the body through the ureters, urinary bladder and urethra.2.Urine is fluid which consists of water, urea and other dissolved wastes.3.The human kidney shows three … Read more

13.1 Homeostasis in Humans

13.1 Homeostasis in Humans 1.   The internal environment consists of interstitial fluid and blood plasma that constantly bathe the cells.2.   Homeostasis is the process of regulating the physical and chemical factors in the internal environment, so that these factors can be maintained in a dynamic equilibrium and optimum condition.  (a) The physical factors include … Read more

Summative Practice 12 – Question 7 & 8 (Form 4 Biology Textbook Exercise and Answer)

Question 7:Explain the effects of stimulant drugs and sedative drugs on the transmission of impulse through the synapse. Answer:• Stimulants such as cocaine prevent the removal of the neurotransmitters that stimulate excitement.• This will produce an intense euphoric feeling followed by depression.• Stimulants also increase impulse transmissions that cause increases in the heartbeat and respiration … Read more

Summative Practice 12 – Question 5 & 6 (Form 4 Biology Textbook Exercise and Answer)

Question 5:Figure 1 shows the cross section of a part of the nervous system.(a) (i) Name structure X.(ii) State the function of structure X.(b) Why is part Y swollen?(c) Complete Figure 1 with neurones involved in a reflex action. Mark the direction of impulse on the neurone.(d) If the spinal nerve is cut at Z, … Read more

Summative Practice 12 – Question 1 – 4 (Form 4 Biology Textbook Exercise and Answer)

Question 1:Compare the functions of the cerebellum and the medulla oblongata. Answer:The cerebellum controls and coordinates body movement as well maintains body balance. The medulla oblongata controls involuntary responses such as peristalsis. Question 2:Define reflex action and state its importance. Answer:Reflex action is defined as a rapid and automatic response without thinking. The ability to … Read more